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                            Air Pollution Aspects of Emission Sources



                                 SULFURIC ACID MANUFACTURING



                                  A Bibliography with Abstracts

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                                  U. S. ENVIRONMENTAL PROTECTION AGENCY
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       AIR POLLUTION ASPECTS

          OF EMISSION SOURCES:

 SULFURIC ACID MANUFACTURING-

 A  BIBLIOGRAPHY  WITH ABSTRACTS
       Office of Technical Information and Publications
         Air Pollution Technical Information Center
                            U.S. EPA-NE1C LIBRARY
                            Denver Federal Center
                            Building 25, Ent. E-3
                            P.O. Box 25227
                            Denver, CO 80225-0227
        ENVIRONMENTAL PROTECTION AGENCY
                Office of Air Programs
         Research Triangle Park,  North Carolina
                    May 1971
For sale by the. Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price Co cents
                    Stock Number 5503-0007

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The AP series of reports is issued by the Office of Air Programs,  Environmental Protec-
tion Agency, to report the results  of scientific and engineering studies, and information of
general interest in the field of air  pollution.  Information  reported in this series includes
coverage of Air Program intramural  activities and of cooperative studies conducted in con-
junction with  state and local agencies,  research institutes, and industrial organizations.
Copies  of AP  reports are available free  of charge to Federal employees, current contrac-
tors and grantees,  and nonprofit  organizations - as  supplies  permit - from the Office of
Technical Information and Publications,  Office of Air Programs, Environmental Protection
Agency, P.O. Box 12055, Research Triangle Park, North Carolina 27709.  Other requestors
may purchase copies from  the Superintendent of Documents, Washington, D. C.  20402.
                      Office of Air Programs Publication No. AP-95
                                            11

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                              BIBLIOGRAPHIES IN  THIS SERIES
r\
                  AP-92,  Air Pollution Aspects of Emission Sources:

                          Municipal Incineration — A Bibliography with Abstracts

                  AP-93,  Air Pollution Aspects of Emission Sources:

                          Nitric Acid Manufacturing —A Bibliography with Abstracts

                  AP-94,  Air Pollution Aspects of Emission Sources:

                          Sulfuric Acid Manufacturing — A Bibliography with Abstracts

                  AP-95,  Air Pollution Aspects of Emission Sources:

                          Cement Manufacturing — A Bibliography with Abstracts

                  AP-96,  Air Pollution Aspects of Emission Sources:

                          Electric Power Production —A Bibliography with Abstracts
                                           L 1 B ift A R  Y
                                       Environm^^i  ;'nt^;n n-

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                                    CONTENTS

INTRODUCTION	vii
BIBLIOGRAPHY
      A.  Emission Sources	    I
      B.  Control Methods	    5
      C.  Measurement Methods	  26
      D.  Air Quality Measurements	  32
      E.  Atmospheric Interaction	33
      F.  Basic Science and Technology	„	34
      G.  Effects - Human Health	39
      H.  Effects - Plants and Livestock (None)
       I.  Effects - Materials	41
      J.  Effects - Economic	42
      K.  Standards and Criteria	44
      L.  Legal and Administrative	45
      M.  Social Aspects (None)
      N.  General	47
AUTHOR  INDEX	49
SUBJECT INDEX	51

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                   AIR  POLLUTION ASPECTS
                     OF EMISSION  SOURCES:
          SULFURIC ACID MANUFACTURING-
         A  BIBLIOGRAPHY  WITH  ABSTRACTS

                             INTRODUCTION
     Sulfuric acid manufacturing contributes significantly to the overall air pollution level
in the United States. To aid efforts to improve air quality, the Air Pollution Technical
Information Center (APTIC) of the Office of Technical Information and Publications,  Office
of Air Programs has compiled this bibliography relevant to the problem and its solution.

     Approximately 200 abstracts have been selectively screened from the  contents of
APTIC's information storage and  retrieval system to cover the 14 categories  set forth in
the table of contents.  The compilation is intended to be representative of available litera-
ture, and no claim is made to all-inclusiveness.

     Subject and author indexes refer to the abstracts by category letter and APTIC acces-
sion number.  Generally, higher accession numbers, representing the latest acquisitions,
cover the most recent material.

     All documents  abstracted herein are  currently on file at the Air Pollution Technical
Information Center, Office of Air Programs, Environmental Protection Agency, P. O. Box
12055, Research Triangle Park, North Carolina 27709. Readers outside the Environmental
Protection Agency may seek duplicates of documents directly from libraries,  publishers,
or authors.

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                                A.  EMISSION  SOURCES
02235
SULFURIC ACID MANUFACTURE, REPORT NO. 2. J. Air
Pollution Control Assoc. 13, (10) 499-502, Oct. 1963.
This report, published as Informative Rpt. No. 2 of the Air
Pollution Control Association's TI-2 Chemical Committee, rr-
presents the 'best thinking of the Association' on the subject
of Sulfuric Acid Manufacture. Of all the chemicals made in
the U.S.,  sulfuric acid is probably produced in the greatest
quantity. In 1961 the U.S. Department of Commerce reported
production of  17,847,812 short tons.  Inasmuch as one ton of
sulfur produces nearly three tons of sulfuric acid,  the  large
proportion coming from  sulfur  is apparent. The  following
processes are reviewed in regard to operations and  air pollu-
tion aspects:  Contact  Process,  Chamber   Process,   Acid
Recovery  Processes.

04946
A. F. Snowball
DEVELOPMENT OF AN AIR POLLUTION CONTROL PRO-
GRAM AT COMINCO'S  KIMBERLEY  OPERATION. J. Air
Pollution Control Assoc. 16, (2) 59-62, Feb. 1966.
During  the  concentration  of  lead and zinc  sulfides  from
Cominco's Sullivan Mine  at  Kimberley,  British  Columbia,
there is   also  produced an  iron  sulfide  concentrate   as a
byproduct. A portion of these iron concentrates is roasted and
the resulting calcine is treated  in electric furnaces to produce
300 tons  of pig iron per day. The sulfur dioxide produced in
the roasting process is  used to make sulfuric acid which is em-
ployed in  the manufacture of ammonium phosphate fertilizers.
Problems  in the control of air pollution resulting from the iron
sintering,  iron  smelting, and fertilizer operations at Kimberley
are discussed, including those arising as a result of almost con-
tinuous expansion of these facilities since their establishment
12 years ago. (Author abstract)

10749
Gobson, F. W.
NEW BUICK  LEAD  SMELTER INCORPORATES FORTY
YEARS  OF TECHNICAL ADVANCES.  Eng. and Mining J.,
169(7):62-67, July 1968.
Four significant innovations in the design and operation of
lead smelters will be combined for the first time when the new
Buick complex goes on stream this year near  Bixby, Mo. The
plant, designed to produce 100,000 tpy  of 99.99% lead, will
feature: updraft sintering, air pollution control through produc-
tion of sulfuric acid, continuous  tapping of molten lead, and
vacuum dezincing. While none of these processes is new, this
will be the first plant to utilize all  four.

12633
F. E. Ireland
POLLUTION BY OXIDES  OF SULPHUR.  Chem. Eng., No.
221, CE261 -262, Sept.  1968.
The sources of sulfur oxide pollution include the combustion
of sulfur-bearing fuels  such as coal, coke, and fuel oil, the
manufacture of sulfuric  acid,  miscellaneous  uses of sulfur
dioxide, and the combustion of  sulfur  compounds in waste
gases from manufacturing processes. This is a brief report of
these pollution sources made to the Working Party on Air Pol-
lution of the European Federation of Chemical Engineering.

12751
McKee, Arthur G. and Co., San Francisco, Calif., Western
Knapp Engineering Div.
SYSTEMS STUDY FOR CONTROL OF EMISSIONS. PRIMA-
RY  NONFERROUS  SMELTING INDUSTRY.   (FINAL RE-
PORT). VOLUME H: APPENDICES  A AND B. Contract PH
86-65-85,  Rept. 993, 88p., June 1969. 72  refs. CFSTI: PB 184
885
A systems study of the primary copper,  lead, and zinc  smelt-
ing industries is  presented to make clear  the technological and
economi factors that bear on the problem of control of sulfur
oxide emissions. Sulfur oxide emissions  for various types  of
smelting  operations are tabulated, including gas flows and
compositions and an analysis of sulfur oxides generation and
recovery. Smelter flow diagrams are presented for the control
methods of contact sulfuric acid, absorption, reduction to ele-
mental sulfur,  lime  wet   scrubbing,  and limestone wet
scrubbing. Sulfur  oxide  recovery processes  that  were in-
vestigated and rejected  as  not being suitable  for economic
analysis  are  listed.  Cost   estimates   for various control
processes are given.

12823
McKee, Arthur G. and Co., San Francisco, Calif., Western
Knapp Engineering Div.
SYSTEMS STUDY FOR CONTROL OF EMISSIONS. PRIMA-
RY  NONFERROUS  SMELTING INDUSTRY.   (FINAL RE-
PORT). VOL I.  Contract PH 86-65-85 Rept. 993, 188p., June
1969. CFSTI: PB 184 884
A systems study of the primary copper,  zinc, and lead  smelt-
ing industries is  presented to make clear  the technological and
economic factors that bear on the problem of control of sulfur
oxide emissions. The nature of smelting  practice is described,
and  potential air  pollution  problems in  smelter areas are
revealed.  Five processes for the control of sulfur oxides are
presented, including contact  sulfuric acid,  absorption,  reduc-
tion to elemental sulfur, lime  wet scrubbing,  and limestone wet
scrubbing. Current sulfur oxide emissions from U. S. smelters
are given, and forseeabl emission trends are discussed. Mar-
kets  for sulfur byproducts are mentioned, the costs of control
by available  methods are   tabulated,  and control method
evaluation with  plant models is considered. A  research and
development program for   control  methods  and smelting
process technology is recommended.

13403
Ganz, S. N., I. Y. Kuznetsov, V. A. Shlifer,  and L. I. Leykin
REMOVAL OF NITROGEN OXIDES,  SULFUR DIOXIDE,
AND SULFURIC ACID MIST AND SPRAY FROM INDUSTRI-
AL EXHAUST GASES USING ALKALINE PEAT SORBENTS.

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                                    SULFURIC ACID MANUFACTURING
(Ochistka vykhlopnykh gazov  ot okislov azota,  semistogo
gaza, tumana i bryzg sernoy kisloty torfoshchelochynymi sor-
betami v zavodskikh usloviyakh.) Text in Russian. Zh. Prikl.
Khim., 41(4):720-725, 1968. 1 ref.
Studies on the purification of exhaust gases from the Mills-
Packard process under industrial conditions  revealed that the
most effective additive to the peat sorbents was ammonia, the
sorption of gases producing a useful organomineral fertilizer.
Addition of the ammonia directly to the  boiling layer of sor-
bent was the most efficient method, and three  sorbent layers
were used.  Successive layer thicknesses  were 200-300,  300-
400, and 400-450 mm with moisture content  35-40,  40-45, and
45-55 percent, respectively.  Raw  material  requirements for
sanitary purification of 60,000 cu m/hr are  (in tons per hr):
0.294 ammonia, 1.5 dry peat,  and  3  peat  with 50 percent
moisture. The ton-per-hour trapping rate was:  0.318 nitrogen
oxides, 0.405 sulfur dioxide, and 0.012  sulfuric  acid. Data are
given for the effectiveness  of  the resultant fertilizer  deter-
mined from agricultural study.

13596
Cunningham, George H. and Allen C. Jephson
ELECTROLYTIC  ZINC  AT CORPUS  CHRIST!,  TEXAS.
Trans AIMEE (Am. Inst. Mining Metallurgical and Petroleum
Engrs.), Vol. 159, p. 194-209, 1944.
The design of the plant includes  the use  of Trail suspension
roasting  equipment,  contact  acid  equipment,  and  batch
leaching in mechanically agitated tanks. Pressure filtering and
washing of leach pulp  and batch purification are followed by
clarification in filter presses  and  cooling of purified solution
by evaporation. Electrolysis is carried out in cells using Tain-
ton alloy  anodes and aluminum cathodes. Cell temperatures
are  held  within  desired  limits  by  circulating cell  solution
through cooling towers. Steam-driven generators are used to
provide direct current for electrolysis. The  cathode  zinc is
melted and cast into slabs for shipment. Plant roasting capaci-
ty is 140 to 240 tpd. Steam is generated in three boilers, each
with a capacity of 6000 to 12,000 Ib of steam per hr at 150 psi,
and amounts to about 0.7 Ib per Ib of  concentrate roasted.
Boiler gas at 8500 to 10,500 cu ft per min and 320 C is  fed to
separate cyclone units.  The gas is passed from the cyclones to
two cottrell precipitators, each with a capacity of 18,500 cu ft
per min at 250 C, and on to the acid plant. The H2S04 section
consists of a standard Leonard Monsanto contact unit using
vanadium mass converters to produce  125 tons of  100%  acid
daily.

13841
Lewis, W. K. and E. D. Ries
INFLUENCE OF REACTION RATE ON OPERATING CON-
DITIONS IN CONTACT SULFURIC ACID MANUFACTURE.
n. Ind. Eng. Chem., 19(7):830- 837, 1927. 7 refs.
Using the data of Knietsch, the authors had  previously calcu-
lated correct operating conditions for the catalytic oxidation of
sulfur dioxide to sulfur trioxide in the presence of platinum.
Further reaction rate data were obtained under strictly isother-
mal conditions simulating plant practice.  From these data, a
new equation  was developed. While it does not explain the
mechanism of the  reaction, it accurately predicts conversion
under any  given set of circumstances. It applies  equally to
SO2 and O2 runs. Optimum operating temperatures calculated
by means of the equation are found to correspond closely with
good plant  practice. A comparison is made  between existing
equations and the new one, and  the shortcomings, both practi-
cal and theoretical, of the earlier forms are discussed in detail.
13850
Thompson, A. Paul
PLATINUM VS. VANADIUM PENTOXIDE  AS CATALYSTS
FOR  SULFURIC ACID  MANUFACTURE. Trans. Am. Inst.
Chem. Engrs., vol. 27:264-309, Dec. 1931.
Platinum  catalysts, including platinized asbestos, platinized
magnesium  sulfate, and platinized  silica gel, are compared
economically and technically with vanadium catalysts on the
basis  of  data  derived  from  sulfuric  plant operations.  The
catalysts are evaluated by such factors as initial costs, cost of
catalyst per daily  ton of 100% acid per year, ultimate cost,
ability to handle gas with a low oxygen to sulfur dioxide ratio,
converter space required, relationship of gas loading or space
velocity to conversion, and life expectancy. Platinized contact
masses are shown to  be cheaper from every standpoint than
vanadium masses.  The 1931 cost of an ounce of platinum is
only 8.57 cents per ton of acid produced. The costs for vanadi-
um masses  are 2.8 to 5.1 times  higher, with one vanadium
catalyst costing nearly 46 cents per ton of acid produced. With
regard to relative  effectiveness,  platinized  catalysts  have  a
lower  kindling temperature,  a greater activity  over a much
wider  temperature range, and they  excel in handling gases
whose sulfur dioxide  content varies from time to time. Their
greater activity with gases of varying sulfur dioxide  content
over broad temperature ranges simplifies  converter design and
operation. Like vanadium catalysts,  platinized silica gel is not
poisoned by arsenic present in the gas  being treated. Addi-
tional  cost  and purification  data on contact  sulfuric acid
catalysts are given in a discussion appended to the article.

15517
Public Health Service, Washington, D. C., National Air
Pollution Control Administration
CONTROL TECHNIQUES FOR SULFUR OXIDE Affi POL-
LUTANTS. NAPCA Publ. AP-52, 122p., Jan. 1969.  274 refs.
About 75% of  sulfur oxide emissions in 1966 resulted from the
combustion of  sulfur-bearing fuels, with coal combustion ac-
counting for the largest  part. The  economic and  technical
aspects of various techniques for controlling these emissions
are examined in detail; they are categorized as (1)  change-over
to fuels with lower sulfur content or to another energy source,
such as hydroelectric  or nuclear power; (2) desulfurization of
coal or residual fuel oil; (3) removal of sulfur oxides from flue
gas by various processes, including limestone-dolomite injec-
tion and alkalized alumina sorption; and (4)  increase in com-
bustion efficiency. Of  the industrial sources of SO2 emissions,
nonferrous primary smelting of sulfide-containing metallic ores
such as copper, zinc, and lead is the largest emitter.  About
half of the primary smelters in the U. S. now use sulfuric acid
recovery to reduce emissions  and  at the  same  time offset
smelter operating  costs.  Smelters,  oil refineries, pulp  and
paper mills, steel plants, sulfuric acid plants, waste  disposal
processes, and a number of other industrial  sources are con-
sidered in terms of present technology for reducing emissions.
The costs of  dispersion of sulfur oxides by tall stacks are
briefly discussed as an approach toward reducing the frequen-
cy of  high concentrations at ground level in some areas, and
an extensive bibliography on gas dispersion is included. An ap-
pendix on chemical coal processing describes the current state
of development of such methods as gasification and liquefac-
tion for reducing the sulfur content of high-sulfur coal.

18305
Lindau, L.
AIR POLLUTION AND THE MANUFACTURE  OF INOR-
GANIC CHEMICALS. (Luftfororening  vid  framstallning  av

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                                            A. EMISSION SOURCES
 oorganiska baskemikalier.) Text in Swedish.  Statens Natur-
 vardsverk, Stockholm, Publikationer No. 4, 66p., 10 refs.
 The investigation deals with air pollution problems in connec-
 tion with the manufacture of basic inorganic chemicals such as
 sulphuric  acid, hydrochloric acid, phosphoric acid,  ammonia,
 nitric acid,  chlorine and  sodium hydroxide. The  report con-
 tains a survey of present conditions, an analysis of various
 technical methods to reduce the emissions, and a discussion of
 the economic consequences of these methods. The purpose of
 the survey is to supply information to the Swedish authorities
 dealing with  air pollution control. The rates of emission from
 the chemical plants are described as kg/ton product. The costs
 of  air pollution  abatement vary. In certain  cases,  e.g.,  the
 recovery of sulphur in connection with the production of am-
 monia, the necessary investments can be written off. In other
 cases, e.g., introduction of the double-contact process for  the
 manufacture of sulphuric acid, the increasing yield can only
 partially motivate the investments  required. There  are also
 cases when the costs  entirely belong to the air pollution  ac-
 count. A comparison between Swedish and foreign plants  in-
 dicates that  emissions are of the same  magnitude. Essential
 improvements  are possible to obtain in new  plants and  the
 latest Swedish production units have applied this to a great  ex-
 tent.

 21221
 Pels, M. and H. L. Crawford
 FEASIBILITY STUDY OF CENTRALIZED AIR-POLLUTION
 ABATEMENT.  (FINAL  REPORT). Battelle Memorial  List.,
 Columbus, Ohio, Columbus Labs. NAPCA Contract PH-86-68-
 84, TAsk 12, 51p., Nov. 17, 1969. 35 refs. CFSTI: PB 190486
 The technical and economic aspects of a centralized air-pollu-
 tion control  plant  located a distance  from seven industrial
 plants were investigated.  The plants  chosen were as follows:
 lime, 200 tons/day; cement, 4500 barrels/day; sulfuric acid, 400
 ton/day; power,  25  Mw; fertilizer, 570  tons/day; gray iron,
 1440  tons/day; and electric arc, 2600 tons/day. Gaseous and
 particulate-emission levels were taken from literature sources,
 and as far as possible, average values were used  for each in-
 dustry. The total amount of gases from the plants  was 627,000
 cfm at 320 F and after mixing.  While the centralized control
 facility is less  expensive to build and operate  than individual
 control devices,  transportation costs are so high  as to make
 the centralized concept  unattractive. The  economics  would
 favor centralized abatement only if each of the seven  plants
 were located at about 1/2 mile from the central facility. This
 distance  is  considered to be unrealistically  close  from  the
 standpoint of an individual plant's land requirements. In addi-
 tion to transportation costs, the centralized plant would render
 emissions  from lime,  cement, and sulfuric acid plants  value-
 less, and any equipment malfunction would release large quan-
 tities of pollutants over a relatively small  area. Finally, vegeta-
 tion growth over buried  pipes would be inhibited, leading to
 potential esthetic problems. (Author summary modified)

 23044
 Ireland, F. E.
 POLLUTION BY OXIDES OF SULPHUR. Chem. Engr. (Lon-
 don), 46(7): CE261-CE262, Sept. 1968.
 Sulfur oxides  arise  from the  combustion of sulfur-containing
 fuels such as coal, coke, and fuel oil; from sulfuric acid  plants
and miscellaneous uses of sulfur dioxide; and  from the com-
bustion of sulfur compounds in waste gases from manufactur-
ing  processes. Many investigations have  been  carried out  on
the  removal of sulfur from fuel and on the removal of  sulfur
oxides from waste gases,  but no generally practical methods
have  been developed. Thus, recourse is made to dispersion
from  suitably tall chimneys to reduce ground-level concentra-
tions  to acceptable limits.  By controlling burner conditions to
limit excess air in the gases, large users of fuel oil and electric
power plants can reduce sulfur trioxide  in waste gases from
40-50 ppm to about 5-10 ppm. In most countries, sulfuric acid
is  produced by contact processes that give a  final acid emis-
sion to not more than two percent of the sulfur burned. Pro-
vided contact plants are equipped with adequate facilities for
preheating,  there  should  be  no adverse local  conditions
produced  by emissions. However, there is  scope for research
into acid mist formation and methods for its prevention at the
source. Emissions from some chemical  processes are  often
more concentrated than those from the combustion of fuel. It
is  common practice to remove the sulfur dioxide in these emis-
sions by scrubbing with alkali solutions.

23972
Weissenberger, G. and L. Piatti
RECOVERY OF SULFUR DIOXIDE FROM WASTE GASES
BY MEANS OF  CYCLICAL KETONES I.  (Ueber die Gewin-
nung  von Schwefeldioxyd aus Abgasen  mil Hilfe cyclischer
Ketone. L). Text  in German. Chemiker  Z., 53(25):245-247,
March 27, 1929. Part H. Ibid., 53(26):266-267, April 10, 1929.
Sulfur dioxide present in waste gas from a sulfuric acid plant
(contact process) in a quantity of 6-7 g per cu m was absorbed
in laboratory experiments by clear technical cyclohexanone
(boiling begin 150/152 Q and  by clear  technical methyl-
cyclohexanone at 15 to 20  C in wash bottles and the absorbed
SO2 was subsequently recovered  by heating the solvents to 80
C.  The absorbed SO2  was determined by titration with an
iodine solution. The quantity of SO2 absorbed by the two sol-
vents varied with temperature, at a practical operating tem-
perature of 15-20 C approximately 0.25% by weight S02 was
absorbed.  The addition of metallic mercury  to the solvents had
a  marked positive or negative effect on the  SO2 absorption
capacity of both solvents depending on temperature. The per-
centage of SO2 in the waste gas affected positively the absorp-
tion capacity of the two solvents from 0 to 5%  SO2.

25178
Teworte, W. M.
SPECDJ1C Am POLLUTION CONTROL ARRANGEMENTS
AT NON-FERROUS METAL WORKS. Preprint, International
Union of Air Pollution Prevention Associations, 41p., 1970. 20
refs. (Presented at the Internationa Clean Air Congress,  2nd,
Washington, D. C., Dec. 6-11, Paper EN-28B.)
Information on the cost problem and on  the necessity for air
pollution control technology in the field of  non-ferrous metals
production is presented.  Their price, high in comparison with
that of steel, is  an incentive to developing any means of in-
creasing the yield and, thus, to recovering the metals from flue
dusts.  Therefore, the center of  air pollution control arrange-
ments shifts to the side  of extracting accompanying elements
in the ores, auxiliary materials, and highly volatile compounds.
The negative biological  effects of a large number of metals
require particularly effective arrangements for waste gas pu-
rification.  More recent specific methods  of air pollution con-
trol are illustrated by  several examples. Fluorine emissions
from  the flux are fought in aluminum works by means of ef-
fective wet purification processes; dry absorption methods are
also being tried.  Fluorine levels of 0.5-1.5  ppb were detected
even in industrial areas where there was no aluminum produc-
tion at all.  Waste gas  purification at  aluminum re-melting
works presents a particularly difficult problem with regard to

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                                    SULFURIC ACID MANUFACTURING
the extraction of very fine salt fumes. The utilization of the
sulfur content in the non-ferrous metal ores is discussed in
detail. Here, the solution to the economic problem of market-
ing a sulfuric acid, aptly called 'acide fatal' by Belgian smelt-
ing works, is as  important as the solution  to  the process
technical problem. The latter was dealt with very successfully
by means of the development of a double-contact process with
intermediate absorption for roasting gases poor in sulfur diox-
ide. The final gases contain less than 0.5% of the SO2 charge.
More  and more processes favorable to air hygiene are being
used by zinc metallurgy. Methods of recovery that cannot be
controlled by waste gas technology, will be discarded. General
and particular information is given on  the cost problem of air
pollution control. Frequently, the wrong conclusions are drawn
from the fact that only 0.2% of the value of industrial produc-
tion are required for direct steps, with secondary injurious ef-
fects, amounting to  1-2%, being prevented in this manner.
Production at some works is hard hit by specific costs of 1-5%
of the proceeds from sales. (Author abstract)

25605
Fulton, Charles H.
METALLURGICAL SMOKE. Bull. Bureau Mines, no. 84:7-94,
1915. 44 refs.
The problem of metallurgical  smoke  (defined as gases and
vapors, an the fine dust entrained by  them) that issues from
stacks  of smeltin and ore roasting plants is considered. Sulfur
dioxide and trioxide are two of the major gases in this case.
They  can combine with atmospheric  water to form sulfuric
and sulfurous acid. The dust that is carried by the gases con-
sists of small particles of the  different ores, fluxes, or fuel.
These emissions can, when combined with certain meteorolog-
ical conditions, cause extensive plant damage, as well as inju-
ry to animals and  humans. The physica and chemical proper-
ties governing the actions of  stack emissions ar discussed. The
effect of the effluent flow speed on the compositio of the flue
dust is considered, and design practices for dust chambers and
stacks  are related. Methods  for the  control of dust emissions
include  settling  chambers,  bag-houses,  and  electrostatic
precipitation. Several operating examples of these controls are
presented.  Several  processes for the  removal of SO2 from
stack gases and its conversion to H2SO4 are given,  including
absorption  and  alkaline   additives. Some  legal aspects  of
smelter emissions  problems  are discussed in terms  of actual
litigation.

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                                B.  CONTROL  METHODS
00587
J.A. Brink, Jr., W.F. Burggrabe, L.E. Greenwell
MIST REMOVAL FROM COMPRESSED GASES. Chem. Eng.
Progr., 62(4):60-66, April 1966.
Fiber mist eliminators have been successfully used to purify
gases and solve  difficult air  pollution  problems involving:
methanol  synthesis gas, sulfonation and chlorination  process
gases, nitric acid process gases, chlorine, and compressed air.
Extensive  research and  development work resulted in the
development of fiber mist eliminators for the collection of sub-
micron mist particles. The first plant-scale  installations were
made for  the  control  of  air  pollution  from  sulfuric  and
phosphoric acid plants. After full-scale units had been proven
highly efficient on stack gases containing submicron particles,
further research was undertaken to develop fiber mist elimina-
tors which would be most economical for the collection of par-
ticles which are predominantly 1 to 20 microns in diameter.
The installation  of  fiber  mist eliminators  within  various
processes to purify gases was started after several difficult air
pollution problems had been solved. The widespread applica-
tion of fiber units to chlorine plants was reported in detail, but
the applications to many other processes has not been  re-
ported previously. It should be noted that mists are present in
many chemical processes at pressures ranging up to  5,500
Ib./sq. in. gauge. The temperatures at whcih mists are present
are usually moderate since many mists vaporize at higher tem-
peratures.

00800
E.P. Stastny
ELECTROSTATIC PRECIPITATION. Chem. bSeng. Prog, 62,
(4) 47-50, Apr. 1966.
The electrostatic precipitator has proven to be the answer to
an important consideration in the production of oleum in the
sulfuric acid industry. Through  its utilization, in addition to its
air pollution abatement role, important production gains have
been made possible. Look not only  at what it can do for your
present  operation conditions, but establish its design  criteria
for ultimate plant capacity so as to insure  full satisfaction at
maximum outputs under future air pollution codes.

01125
D. Zanon and D. Sordelli
PRACTICAL SOLUTIONS OF AIR POLLUTION PROBLEMS
FROM CHEMICAL PROCESSES . (Realizzazioni nel  Campo
delia Prevenzione dell' inquinamento Atmosferico di  Origine
Industriale.) Translated from  Italian.  Chim.  Ind.  (Milan),
48(2):251-261, March 1966.
A strict control of pollutant to be dispersed in the atmosphere
offers technical and economic  problems,  both in the design
and the  operation of chemical  processing units. Three exam-
ples  of  processes  for  which  pollution  control  has  been
established are described: SO2 derived from contact sulfuric
acid and from hydroxylamine sulfate plants, nitrous gas from
low and high-pressure  nitric acid plants, and fluorine-contain-
ing effluents from hydrogen fluoride production. The  general
approach,  kind of abatement process adopted, materials and
construction costs are discussed.

02355
S.T. Cuffe CM. Dean
ATMOSPHERIC   EMISSIONS  FROM  SULFURIC  ACID
MANUFACTURING PROCESS;  A COMPREHENSIVE  AB-
STRACT. Preprint. (Presented at the 58th Annual Meeting, Air
Pollution Control Association, Toronto, Ontario, Canada, June
1965.)
This paper includes basic  descriptions of both  the  chamber
and contact processes.  Variations  in process conditions  that
may appreciably  change the magnitude of emissions, e.g., the
manufacture of oleum or the  use  of different sulfur bearing
feed materials, are noted. Concentrations of both nitrogen ox-
ides and sulfur dioxide emissions from chamber plants were
found to range from about 0.1 to 0.2 volume percent. The  con-
centration  of  combined acid mist and spray from  chamber
plants varied from about5 to 30 milligrams per cubic foot. For
contact  plants, the range of sulfur dioxide concentrations in
the absorber exit stack ranged from 0.13-0.54 volume percent;
while acid  mist  concentrations varied  from 1.1  to 4.8 milli-
grams per  cubic foot. The test data show that it is  possible to
recover  99 percent of all of the acid mist and spray emissions
by adding commercially available mist elimination. (Author ab-
stract)

02985
K. Stopperka
ELECTROPREdPITATION  OF  SULFURIC ACID  MISTS
FROM THE WASTE GAS OF A SULFURIC ACID PRODUC-
TION PLANT. Staub (English Transl.) 25, (11) 70-4, NOV.
1965. CFSTI TT66-51040/11
Optimum conditions for electroprecipitation of  sulfuric  acid
mist from waste gas in sulphuric acid production have been in-
vestigated  in a pilot plant. The specific effect of the  shape of
the discharge  electrode  has been tested in addition to the in-
fluence  of collecting  electrode   dimensions and  different
moisture contents on separation efficiency. The tests which
have been carried out with a 'Korobon' filter pipe (electrode
graphite) indicate that the corrosion problem has been solved
permanently. (Author summary)

03129
Avy., A. P.
METHODS  OF  REDUCING  POLLUTION CAUSED  BY
SPECIFIC INDUSTRIES. (CHAPTER VI. CHEMICAL INDUS-
TRY). European  Conf.  of  Air Pollution, Strasburg,  1964. p
337-356.
The pollutants discharged  by  the  chemical industry  may be
subdivided into several  classes. The first and most important
class is that of harmful products emitted in large quantities by
the 'heavy' chemical industry  and,  in particular,  organic
chemical works:  Sulphur  dioxide, sulphuric acid,  chlorine,
whether manufactured or in the form of impurities  in the basic

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                                    SULFURIC ACID MANUFACTURING
material: fluorine in the case of fertilizers and fluorine again in
aluminum electroechemistry. The chemical industry has a wide
range of special problems which is in a  constant state of flux
owing to the wide and ever-increasing variety of new synthetic
products (intermediate and finished) in  the  organic chemical
industry. From the technical point of view, the prevention of
pollution by such products depends on their presentation and
manner of application.  A problem  directly  connected with
chemical manufacture is  that of smell: mercaptans, hydrogen
phosphide, methylamines, etc., although, of course, it does not
arise in the chemical industry alone. Technical methods used
to reduce pollution  are highly devellped for  dusts and smoke
and there is a wide choice of apparatus. The chemical indus-
try, like all others, is subject to laws and regulations governing
industrial air pollution.  A  fairly  sharp  distinction, however,
should be  drawn between laws,  which lay  down in  general
terms the objects to be attained and the obligations to be ful-
filled, and the regulations which embody detailes of the limits
imposed and the degree of reduction demanded. In this last re-
port, caution is necessary and impossible or unnecessary stan-
dards should not be set. It is clear that international liaison or
even  international  collaboration  is  not only desirable,  but
necessary.

03945
F. T. Meinhold
THREE-WAY PAYOUT FOR H2SO4 GAS CLEANER. Chem.
Progress 29, (3) 63-4, Mar. 1966.
A compact and efficient  acid gas cleaner was  installed in the
top of each absorber and was adapted to the  acid absorbers.
Another potential air pollution source was  quenched in the
plant which involved the acid drying towers. Elimination of
the course mist not only prevents corrosion in the connecting
duct, but also reduces the over-all vol. of mist leaving the ab-
sorbers.  Each of the 900-tpd. acid plants was completed on a
turn-key basis in 8 months. The exhaust  stacks cleared in only
50  min.  and now,  after regular scheduled  shut-downs,  the
stacks are usually cleared in 5 to 30 minutes,  depending on the
length of shut-down.

04067
E. O. Kossovskii
SANITIZATION OF IRON PYRITES GRINDING  AT THE
M.B. FRUNZE SULFURIC ACID PLANT. Gigiena i Sanit. 28,
(1) 77-9, Jan. 1963. Russ. (Tr.) (Translated by B. S. Levine in
U.S.S.R. Literature on Air Pollution and Related Occupational
Diseases, Vol. 12.)
The iron pyrite grinding  department at the M. F.  Frunze  sul-
furic acid plant  was an intense source  of fine air-suspended
dust which was coming  from the transportation,  unloading,
grinding, and loading of the groundbore onto the small transfer
cars. The entire pyrite grinding process  was accomplished in
an inclosed brick building. Fine dust was intensely liberated
into the  surrounding air  at each step of the procedure. The
density of the air-suspended pyrite dust was inversely propor-
tional to  the moisture content of raw ore, but the temperature
of the air generally  reduced the  initial  moisture  of the raw
pyrite by 65-70%, and under the prevailing ore grinding condi-
tions it was not possible  to raise the moisture content of the
material artificially.  Attempts  to sanitize the working condi-
tions had to be limited to encasing points of dust generation
and to establish a suitable system  of leak-proof ventilation.
Before the sanitary improvements  in  the  process  of iron
pyrites grinding were instituted the density of the generated
and air suspended pyrite dust was great and constituted a seri-
ous sanitary problem. The density of the iron pyrite dust in the
air surrounding the process was to a degree inversely propor-
tional to the moisture content in the raw ore. The sanitary im-
provements  consisted basically  in  leak-proof  encasing  of
strategic dust generating production points and in instituting an
arterial ventilation system.

05079
N. Morash, M. Krouse, and W. P. Vosseller
REMOVING SOLID  AND MIST  PARTICLES. Chem.  Eng.
Progr. 63, (3) 70-4, Mar.  1967.
The  laboratory  and  pilot plant  development work for  a
technique which successfully removes submicron size dust and
acid mist particles from  exhaust gases is described. The result
obtained when an irrigated, thin,  felted  fiber filter is used to
remove a mixture of fine titanium dioxide and sulfuric acid
mist particles  from the exhaust gases of pigment calciners is
discussed.

05514
R. L. Gotham
ELECTROSTATIC PRECIPITATION OF SULPHURIC ACID
MISTS. Proc. Clean Air Conf., Univ. New South Wales, 1962,
Paper 20, Vol. 2, 16 p.
The  most important feature  of  electrostatic precipitators is
their ability  to remove very small concentrations of finely di-
vided particulate matter, at high efficiency,  from extremely
large gas flows,  in a plant of moderate  size  with a low pres-
sure drop across the equipment. Although little is known in re-
gard to the  phenomena  encountered, the process of electro-
static precipitation has gained world-wide acceptance as one of
the most  efficient collection  systems known, and for many
years has  been successfully applied to the problem of sulphu-
ric acid mist removal. In this  application, single-stage Cottrell
precipitators with a wire and tube electrode arrangement are
usual. Industrial  precipitators are normally operated with their
discharge electrodes at as high a negative potential as possible
without sparking in order to obtain maximum particle migra-
tion  velocities. For the treatment of gaseous  effluent from
contact sulphuric acid plants, efficiency tests  have indicated
average migration velocities in the range of 0.40 to  0.60 ft/sec
with attendant fficiencies in the order of 99.7%. The Deutsch
Equation,  relating  efficiency  with  migration  velocity  and
specific collecting  area,  is a satisfactory basis for  equipment
design  and comparisons  provided that the value of migration
velocity used in  the equation is an empirical  or average value
determined from plant wxperience or pilot plant studies  on a
similar application. (Author abstract)

05567
L. Silverman
HIGH  TEMPERATURE  GAS AND AEROSOL REMOVAL
WITH  FD3ROUS FILTERS. Proc. Air Water Pollution Abate-
ment Conf.,  1957. pp. 10-23m.
The use of a slag wool fiber filter as an inexpensive cleaner of
high temperature gases  and fumes produced in open hearth
steel furnaces was described and evaluated.  These fibers are
small (4 microns mean diameter) and are refractory, thus able
to withstand  temperatures of  1100 F.  ;or  high  efficiency
separation of fine aerosols, fine targets in large number are
necessary which  packed  slag  fiber   layers  can provide.
Theoretical,  laboratory and field studies show that slag wool
filters show efficiencies ranging  from 90 to  99%,  depending
upon fiber layer compositions, density, and thickness. The
chief separating mechanisms appear to be diffusion and impac-
tion. Results are presented of the air flow resistance charac-

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                                            B. CONTROL METHODS
 teristics of a  rotary  screw agglomerator,  used  to  provide
 dynamic gas treatment to increase particle size of the efficien-
 cy of the  screw as an inertial collector for iron oxide fume.
 The collection efficiency and resistance characteristics of slag
 wool fiber  filters was extended  to other aerosols and  gases
 such as fly ash, sulfur dioxide, hydrofluoric acid and sulfuric
 acid mist. The filter (one inch thickness, five pounds per cubic
 foot density) at velocities used for collecting iron fume (50 to
 150 feet per minute) showed efficiencies for SO2 of approxi-
 mately 30% when moist and zero when dry.  For hydrogen
 fluoride (dry and wet), efficiencies range from 70 to 90%. For
 fly  ash resuspended from Cottrell ash,  efficiencies ranged
 from 60 to 90%,  whereas when  feeshly formed fly ash was
 created by burning powdered fuel, efficiencies ranged from 93
 to 99%. A revised pilot model slag wool filter was constructed
 for 750 to  1000 cfm gas flow based on results of the first field
 unit.

 06247
 SULFURIC ACID MIST IS CLEANED FROM AIR BY FOG
 FILTER SYSTEM. ((Air Eng.)) 9(3):24-25, Mar. 1967.
 In the making of TNT, contaminants such as sulfuric acid mist
 are emitted to the air. A relatively new method of cleaning  air,
 the  fog  filtration system is essentially  a   high  pressure
 scrubbing operation in which vaporized water cleans  the pol-
 luted air is silo- shaped chambers  spaced about 50 ft. apart.
 The air-cleaning system is  actually a three-stage operation. Its
 functioning is  described: (1) Polluted air is drawn through one
 of  seven Cottrell electrostatic  precipitators, where entrained
 moisture  receives electric charges from electrodes,  (2) The
 now partially clean air is drawn into  one of the three fog fil-
 ters, where it is washed under high pressure, pulled downward
 in a swirling pattern, is then drawn up through  a pipe and ex-
 pelled, with virtually all impurities removed, and (3) The ef-
 fluent (dirty) water flows  from the bottom of  the filter to a
 collecting basin several hundred feet away, where it is treated
 and discharged.  These three powerful fans  draw  the con-
 taminated air from the electrostatic precipitators are big units:
 21 ft. high,  20 ft. wide,  and 10 ft.  deep. Once the acid-polluted
 air is  drawn  into them,  the  suspended  matter in  the  air
 acquires a  charge and  is precipitated at the ground  surface.
 Droplets so precipitated unite to form a liquid which drains
 down  the sides of the  tubes and  is collected below. The next
 step is the  suction of  the  still acidic polluted fumes  through
 the fog filters. Then the air is given a thorough scrubbing with
 fog particles. The wetting nature of the high pressure  fog per-
 mits fine particles to be 'centrifuged' out of the air by a  simu-
 lated cyclone  action in the wetted gases. Fog  particles from
 high pressure  nozzles  provide an excellent  induced  draft air
 pump,  because all air  entrained  must necessarily move with
 substantially the same  velocity as that of the fog particle. The
 system is virtually maintenance-free, even though the filters
 are operating on a 24 hour a days basis to keep the air clean.
 Beyond a  routine schedule of cleaning  the filter chambers,
 there is no requirement for maintenance manpower.

 06282
 A. S. Arkhipov, A. N. Boytsov
 TOXIC AIR POLLUTION FROM  SULFURIC ACID PRODUC-
 TION. Gigiena  i Sanit., Vol. 31,  p. 12-17, Sept. 1962. 5 refs.
 Engl. transl. by JPRS-R-8824-D, p. 1-7, Nov. 11, 1967.
 In order to analyze working conditions in  the  production  of
 sulfuric acid against  a  background  of technical  progress and
 modernization  of the progress, data on air pollution were col-
lected in furnace sections of sulfuric acid shops at 12 chemical
plants. Technical progress, the introduction  of  new calcining
methods for pyrite, the mechanization of many manual opera-
tions, the introduction of automation features, better ventila-
tion and other means have improved  working conditions in
kiln shops of sulfuric acid plants. The  concentrations of S02
in a number of plants producing sulfuric acid have dropped to
permissible levels.  The reduction in SO2 concentration to per-
missible levels and the marked reduction in clinker dust have
been achieved  even  during  increased  technical  progress,
greater charges of raw materials and gas per cubic meter of
furnace and cubic meter of building volume  and the greater
production of sulfuric acid plants.

07535
W. Leithe
CLEAN AIR MAINTENANCE - AN IMPORTANT TASK FOR
CHEMISTRY  AND ECONOMY.  (Reinhaltung der Luft   ein
dringendes Anliegen fur Chemie und Wirtschaft.)  Text in Ger-
man. Allgem. Prakt.  Chem. (Vienna), 18(8):239-241,  Sept.  10-
17, 1967. 4 refs.
This article is a summary of two lectures given at meetings of
chemical societies.  The problem of air pollution and some con-
trol methods are outlined. Typical examples of well-known air
pollution problems are mentioned: London's smog chiefly
caused by domestic heating, the smog of Los Angeles due to
automobiles, the sun, and temperature inversions, and the in-
dustrial air pollution of the Ruhr Valley. Some characteristic
data for all three examples are quoted. The techniques for the
control  of dust emissions  are  farthest advanced.  This  is
verified by the fact that in Germany, emission of cement dusts
decreased to one third while the production of cement tripled
in the last 17 years. Far less satisfactory is  the control of SO2
emissions. About twice as much sulfur is  blown into the air
than is used for the production of sulfuric acid. Some wet and
dry processes for the elimination of SO2 from smoke are men-
tioned, but no method is known today which is both effective
and economical. The chemical industry tackled  its  problems
mostly by reducing the emission of air polluting substances by
increasing the  efficiencies of the  relevant chemical processes.
Examples are  the production  of sulfuric acid  and nitric acid.
Organic compounds can be recovered by either absorption on
activated charcoal or oxidation by catalytic afterburners.

07552
Billings, Charles  E., Charles Kurker, Jr., and Leslie Silverman
SIMULTANEOUS REMOVAL OF ACID GASES, MISTS, AND
FUMES WITH MINERAL WOOL FILTERS. J. Air  Pollution
Control Assoc., 8(3): 195-202, Nov. 1958. 20 refs. (Presented at
the  51st  Annual  Meeting, Air  Pollution Control Assoc.,
Philadelphia, Pa., May 26-29, 1958.)
Investigations have indicated that two in. thick filters at four
Ib/cu. ft. packing density will remove up to 80%  of  acid mist
and up  to 99% of  acid gases and fumes. Total filter life  de-
pends upon concentration of contaminant in the entering air. A
summary of filter  performance is given. Estimated  operating
life based upon one use of the filter material can be obtained
from the data given. With particulates such as iron oxide and
fly ash, it has been found possible to  wash and reuse filters
about ten times. When iron oxide was collected simultaneously
with SO2, filters were reused about eight times. Acid gas col-
lection is significantly improved by the presence of moisture
on slag wool filters. Mineral wool filters have  several features
such as,  low cost  (about 1 cents/lg.), small fiber diameter (4
micron and ability to withstand high temperatures (1000  deg
F.). Slag wool will  simultaneously remove sub-micron particu-
late  materials  with 90 to 99% efficiency.  Resistance to flow
through two in.  slag  wool filters (with an HF efficiency of

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8
SULFURIC ACID MANUFACTURING
95%) is on the order of one or two in. of water, or if continu-
ously moistened, at most 6 in. of water.

07925
Beighton, J.
THE SPECIAL INDUSTRIAL PROCESSES. Roy. Soc. Health
J. (London). 87(4):215-218, July-Aug. 1967. 2 refs. (London)
The  air pollution problems of  a group of industries  which
produce: sulfuric acid, nitric acid, petroleum  and petrochemi-
cals, iron and steel, copper, aluminum, gas, ceramics and elec-
tric power  are reviewed. The basic  technical approach is to
avoid the formation of the emission by design of the process,
then to require the treatment of any unavoidable emission, and
finally to require adequate dispersal of any  residual amount
which has to be discharged. The legislation is designed to com-
promise between safeguarding of public health and amenities
and providing  for a realistic acceptance with adequate control
of special processes. Although the loss of gases in the  manu-
facture of sulfuric acid is limited to 2% of the sulfur burned,
the loss from a contact acid  plant  with a  500-ton-per-day
capacity may be considerable so that chimney heights as high
as 450 ft may be required. Acid mist from contact plants burn-
ing sulfur is a special problem as it is difficult to control and
its  occurrence is unpredictable. There  are  two  nitric acid
plants  in Britain equipped with catalytic tail-gas  reduction
units which should solve the problem of brown nitrous fume
emission to the air. The use of special  flares is  required to
control H2S and mercaptans emitted by oil refineries.  In the
steel  industry the  development of  the  Fuel-Oxygen-Scrap
process is regarded as an alternative to the  electric arc fur-
nace. It is claimed that melting and refining can be  carried out
without exceeding a fume level of 0.05 grains per cu ft.

08181
Varlamov, M.  L., G. A. Manakin, and Y. I. Starosel'skii
PURIFICATION OF EXHAUST GASES OF A  SULFURIC
ACID TOWER PLANT BY A FLOWMETER PIPE TYPE OF
APPARATUS.  Zh. Prikl.  Khim., 31(2): 178-186, 1958. 19 refs.
Translated from Russian by Bture on Air Pollution and Related

4, p. 68-77,  Aug. 1960. CFSTI: TT 60-21913
A  venturi apparatus for the recovery of spray, sulfuric acid
aerosol, and nitrogen oxides from the exhaust gases of a sul-
furic acid tower plant is described. The  experimental arrange-
ment consisted of two units: a small assembly, producing up
to  50 cu in/hour, and a  larger  one  producing up to 500 cu
m/hour. In one apparatus, the fluid entered the main channel
at  an angle; in a second  apparatus, the fluid entered tangen-
tially and became distributed evenly over the perimeter of the
diffuser. A third apparatus had a radial fluid feed in relation to
its main axis.  The separator walls of the small unit were ar-
ranged concentrically which forced the passing gas  to impinge
upon the surface of  the  liquid  twice in succession. Another
type of tube was tested in connection with the large unit. This
tube had two radial fluid  feeds set at 90 deg, and a separator
of the type  of abbreviated cyclone TsKTI. The power con-
sumed in the  operation of the flowmeter tube type of ap-
paratus in the purification  of exhaust gases emitted by the
tower nitrose  system ranged between 5 6 kilowatt-hours per
ton of H2SO4, or 10 to 12% of the total power used  in the
production of one ton of sulfuric acid by the nitrose method.
                         09126
                         Moeller, W. and K. Winkler
                         THE DOUBLE CONTACT PROCESS FOR SULFURIC ACID
                         PRODUCTION. J. Air Pollution Control Assoc., 18(5):324-325,
                         May 1968. 1 ref. (Presented at the 60th Annual Meeting, Air
                         Pollution Control Assoc., Cleveland, Ohio, June 11-16, 1967,
                         Paper No. 67-115.)
                         In the Bayer double contact process the reaction is interrupted
                         after approx. 90% SO2 has been converted to SOS. The SOS is
                         removed in a first  absorption stage the so-called intermediate
                         absorption and  the remaining SO2-air mixture is once more
                         reacted at the contacts. By removing the SOS during the inter-
                         mediate absorption, the distance of the remaining gas mixture
                         from the state  of  equilibrium is increased and this permits
                         further reaction, which means higher degrees  of conversion.
                         Theoretically, the double contact process allows the conver-
                         sion degree to be increased from approx. 98%  for the normal
                         contact process to approx. 99.8%, and thus a reduction of S02
                         emitted by a factor of ten. After the intermediate absorption,
                         the  temperature at which the catalyst begins to respond is
                         about 50 degrees C lower than usual. This greatly helps to con-
                         trol air pollution, since the more favourable state of equilibri-
                         um  further cuts down the quantity of emitted SO2 by at least
                         50% at a temperature which  is 50 degrees C lower. The SO2
                         concentration emitted by  the  double contact plant,  based on
                         elemental sulfur, does not exceed 240 ppm at 20% overload
                         and is as low as 100 120 ppm SO2 at normal load. Plants which
                         have now been  operating for 3 years on the basis of pyrites
                         still give the same degree of conversion of 99.7%.

                         09559
                         Hensinger, C. E., R. E. Wakefield, and K. E. Glaus
                         TURNING POLLUTION GASES INTO PROFITS. Eng. Mining
                         J., 169(2): 131-135, Feb. 1968.
                         Fluid Column zinc roasters have been developed to process
                         pelletized zinc concentrates with the resulting sulphur dioxide
                         in the roaster gas used to produce sulphuric acid in a contact
                         plant. These  installations  reflect the modem trend  toward
                         more efficient roasting processes and sulphuric acid plants of
                         larger tonnage. In  Fluid  Column roasting several contiguous
                         fluidized  beds  of  pelletized  zinc  concentrates  of varying
                       OoJagmtienai BttrtnJeaceVate superimposed one  on top of the
                         other without intervening mechanical grates. Air is the primary
                         fluidizing agent, however, provision is made for the introduc-
                         tion of other gases to produce different  conditions in  each
                         bed, e.g. the lowest may be oxidizing while the  upper bed may
                         be reducing.  The roasting process and the sulfuric acid plant
                         are described in some detail.

                         09913
                         Guyot, G. L. and J. P. Zwilling
                         SNPA'S PROCESS  FOR H2SO4 PRODUCTION DEVELOPED
                         WITH EYE ON ADX POLLUTION. Oil Gas J.,  64(47):198-200,
                         Nov. 21, 1966.
                         A new process  provides  for  reducing the sulfur content of
                         residual gases to a  very low level and converting the removed
                         sulfur into high concentration (92 to 94%) H2SO4. The new
                         process purifies exhaust gases containing up to  30 vol % steam
                         and 0.8 to 3.0 vol % sulfur derivatives. The gases, after trans-
                         formation of sulfur compounds  into SO2 go through a mul-
                         tibed catalytic converter to transform SO2 into  SOS. The con-
                         version rate varies  from  90 to 95%, depending on initial SO2
                         concentration. The  SOS is condensed, in  the form of sulfuric
                         acid of  92  to 94%  concentration. The  SOS-rich  gases are
                         cooled to a temperature  slightly higher than their dew point.

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                                           B.  CONTROL  METHODS
 Then they are sent to an absorption tower for countercurrent
 washing and cooling by the acid already produced. No filters
 or electrostatic precipitators are  needed. An acid of 92 to 94
 wt% concentration can be made from a gas with less than 1%
 SO2 and up to 30% water.

 11058
 W. Teske
 IMPROVEMENTS IN THE  PROCESSES AND OPERATION
 OF PLANTS IN THE CHEMICAL INDUSTRY LEADING TO
 REDUCED  EMISSION. Staub (English translation),  28(3):25-
 33, March 1968. CFSTI: TT 68-50448/3
 The emissions from chemical plants can be reduced, in special
 cases, by changing the  production process  or, in general, by
 using a gas cleaning method. Change in the production process
 may be achieved by a basic alteration of the process itself, by
 changing the mode of operation, by modifying the equipment
 and by using a different raw material.  For this purpose, the
 doublecontact method for sulphuric acid production, the pres-
 sure method for nitric acid recovery and the introduction of a
 covered carbide furnace are mentioned as examples.  The su-
 perphosphate process,   viscose  process,  production  of
 betanaphthol, production of thermal  phosphoric  acid and
 production  of calcium  chloride  are given as  examples for
 waste gas cleaning. (Author's summary)

 11146
 Anon.
 SULPHUR.  A HIDDEN  ASSET IN SMELTER GASES. PART
 4. Eng. Mining 169(8):59-66, Aug. 1968.
 Smelter and converter gases and their contained  sulfur are a
 specialized  problem which may  be  turned into an asset for
 profit.  The  worldwide  application  of  technology  to this
 problem is reviewed Process description and applications are
 discussed.

 11235
 J. A. Brink, Jr., W. F. Burggrabe, and L. E. Greenwell
 FIBER   MIST   ELIMINATORS  FOR  SULFURIC  ACID
 PLANTS. Preprint, Monsanto Co.,  St.  Louis,  Mo.,  ((31))p.,
 1968.  10 refs. (Presented at the Symposium on Sulfur,  Sulfuric
 Acid and the Future, Part n, 61st Annual Meeting, American
 Institute of Chemical Engineers, Los Angeles, Calif., Dec. 1-5,
 1968, Paper 6-F.)
 Fiber mist eliminators not only utilize the mechanisms of im-
 paction and  interception on the large  and intermediate size
 particles, respectively, but also are the only type of equipment
 which can be designed to utilize the Brownian movement of
 particles to effect extremely high collection efficiencies in the
 low and sub-micron ranges. Collection efficiences on particles
 greater than 3 microns are essentially 100% while efficiencies
 as high as 99.98% on all  remaining particles 3 microns and less
 in size can be achieved depending on design and economics.
 High efficiency fiber mist eliminator elements for sulfuric acid
 plants plants consist of fibers packed between two concentric
 screens. Mist particles collected on the  surface of the fibers,
 become a part of the liquid  film which wets the fibers. The
 liquid  film is moved horizontally  through the fiber bed by the
drag  of the gases  and is  moved  downward by  gravity. The
Liquid  drains down  the inner screen to the bottom  of  the ele-
ment and then to a liquid seal pot. The liquid overflows the
seal pot continuously back to the process.
11238
R. R. Dukes, and M. D. Farkas
SULFUR SHORTAGE VS PLANT DESIGN. Preprint, Leonard
Construction Co., Chicago, LI., 25p.,  1968. 5 refs. (Presented
at the  61st Annual Meeting, American Institute  of Chemical
Engineers,  Symposium on Sulfur,  Sulfuric Acid  and the  Fu-
ture, Part I, Los Angeles, Calif., Dec. 1-5, 1968, Paper 5-C.)
Sulfuric acid plants can be built using  SO2 bearing gases from
various sources. The  most important  characteristic from  the
viewpoint of  economics is the SO2 concentrations. Catalyst
poisons such as fluorides should be avoided, and  the SO3  and
paniculate  contents should be as low  as possible. If the S02
content is low, the operating costs  will be  high because of in-
creased utility requirements as fuel to keep the plant in ther-
mal balance,  and a power to supply  refrigerated water. The
amortization costs will be high because of the increased capital
requirements. (Authors' summary)

11250
C. F. Scheidel
SULPHUR  DIOXIDE  REMOVAL FROM TAIL GAS BY THE
SULFACID   PROCESS.   Preprint,   Lurgi   Apparatebau
Gesellschaft  mbh,   Frankfurt  (Germany),  ((25))p.,   1968.
(Presented  ath the 61st Annual Meeting, Symposium  on Sul-
fur, Sulfuric Acid and the Future, Part n, Los Angeles, Calif.,
Dec. 1-5, 1968, Paper  6 E.)
A sulfur dioxide removal process is described. Gases contain-
ing SO2  are passed through  an activated carbon reactor and
optimum removal of  SO2 is reached  if the gas  is saturated
with water at a temperature  of approximately 160 degree F.
The bed of activated carbon is sprayed with water. The fol-
lowing process steps are required for wet catalytic conversion
to sulfuric acid: 1) adsorption of SO2 milecules 2)  oxidation of
SO2 3) removal of SO3 by flushing with water 4) increase of
solubility of S02 with lower sulfuric acid  concentration in
liquid film 5) the rate of H2SO4  adsorption increases with
H2SO4 concentration which slows  down SO2 diffusion in  ad-
sorbent.  A description of the chemical plant and equipment
used in this process is given along with operating costs.

11629
Zwilling, J. P. and G. Guyot
RECOVERY OF THE WASTE GASES FROM CLAUS UNITS
FOR THE PRODUCTION OF SULFURIC ACD3. Erdoel Kohle
(Hamburg), 21(5):290-292, May 1968.  (Presented  at  the 19th
Annual Meeting of the German Society for  Petrology and Coal
Chemistry, Hamburg, Oct. 6, 1967.) Translated from German.
8p.
At a  natural gas purification plant,  separated  acid  gas is
processed to sulfur in a Claus unit. Since  five percent of  the
sulfur was removed as sulfur dioxide with the waste gases, a
continuous  catalytic oxidation process was developed to con-
vert sulfur  compounds to sulfur trioxide and to recover con-
centrated sulfuric acid. The oxidation of the sulfur compounds
is preceded by the combustion of  residual gases  at 540 C to
oxidize hydrogen  sulfide to  sulfur dioxide  and  by  the sub-
sequent cooling  of the combustion  gases at 410 C. The sulfur-
containing gases are then contacted with a vanadium catalyst
in an  adiabatic  converter;  oxidation takes  place with  the
release of heat.  Gases leaving the converter are cooled to  275
C and  then passed to a concentration tower where they  are
contacted  with  90-94% sulfuric   acid   in  a  counterflow
precedure. Gases from the concentration tower flow- to an ab-
sorption  tower where the sulfuric acid  vapors are scrubbed
with  80-85% sulfuric  acid. The gases impart their heat to  the

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 10
SULFURIC ACID MANUFACTURING
acid; since the absorption by the sulfuric acid also generates
heat, the circulation absorption-sulfuric acid is cooled in gra-
phite exchangers. Any acid remaining in the gases is removed
by a Teflon filter; no electrostatic filters are required. Produc-
tion of sulfuric acid is 65,000 to 140,000 ton/yr. The concentra-
tion of the acid is 91-94%.

11906
Hilder, Wolfgang
A NEW  SULPHURIC  ACID  INSTALLATION  REDUCES
SULPHER DIOXIDE EMISSION. ((Neue  Schwefelsaureanlage
verringert Schwefeldioxidemission.)) Text  in German.  Stad-
tehygiene, 19(6):125-127, June 1968.
An increased (24%) consumption of sulfuric acid (H2SO4)
(used in the manufacture of fertilizers, vitamin pigments, ar-
tificial fibers, etc.) in the German Federated Republic over the
last 5 years, a 78% H2S04  made in the Chamber and Tower
Process which did not fulfill  all purity requirements,  and a
shortage of elemental sulfur caused interest in the Pyrite-roast-
ing Process of H2SO4 production. Copper, zinc,  and a purple
ore which is a valuable raw material in the iron  industry, are
also  by-products of this process. With a daily production of
650 tons,  the new pyrite-buming, H2SO4  installation of the
Hoechst Dye Works is one of the largest  plants of its  kind.
This non-urban, modern factory, which utilizes a closed com-
bustion and exhaust system and a highly effective noise-isola-
tion system, performs 4 operations: heat utilization, gas clean-
ing, contact,  and  absorption. The dust-containing mixture of
SO2 and  air is freed  of floating particles and moisture in
hot,roasting ovens used also in the manufacture of steam and
electricity. The dust from the ovens and from the gas cleaning
is collected for further utilization. The cleaned gases, emitting
only 1/5 the amount of SO2  as the earlier process, escape after
final absorption through a stack 135 m in height. The improved
contact operation, which oxidizes SO2 to SO3, produces most
of the H2SO4 in the Federal Republic (90%) and U.S.A. (95%).
Since only 2%  of  the  SO2 emissions are  contributed by all
H2SO4 manufacturers in West Germany, it is a fallacy to be-
lieve that the new  installation will reduce atmospheric  SO2
pollution substantially. The overwhelming portion of SO2 pol-
lution is emitted from heat  or electricity-producing fossil fuel
installations.

13206
Bulicka, Milan, Jaroslav Podmolik, and Josef Hajek
ECONOMY  OF  ABSORPTION  UNIT   INSERTED   FOR
LOWERING OF EXHALATIONS FROM SULPHURIC ACID
PRODUCTION PLANT. (Ekonomie vyroby kyseliny sirove s
vlozenou absorpci).  Text in Czech. Chem. Prumysl (Prague),
19(3):140-142, 1969. 5 refs.
When the daily production of sulfuric acid ranged to 100 t/day,
with 95 to 97% conversion and with an average absorption of
99%, even with relatively low chimney heights, the immediate
vicinity of factory was free  from emissions. When production
exceeded  300 t/day,  higher chimneys  did  not  sufficiently
reduce the local  concentrations. In  most  plants using the
heterogeneous  oxidation manufacturing method, SO2 emis-
sions are 0.2  to 0.4%,  SO3 emissions are  0.02 to 0.1%, and
H2SO4 emissions are 0.075%. For the work in Prerov, which
produces 100,000 t/year, a  two  stage exothermic process of
catalytic oxidation of SO2 was adopted. Output is higher than
103,000 t/year, and  10 kg of  sulfur are recovered for 1 t of the
manufactured sulfuric acid.  The  process uses a closed circuit
of cooling water which requires 20% more water than with
traditional methods, and 3.5 kWh/t  more  sulfuric acid,  and
which produces 10 kg less of  steam per ton of sulfuric  acid.
                         The cost of the absorption equipment is offset by the value of
                         the sulfur recovered. The greatest advantage of the unit is its
                         reduction of harmful emissions.

                         13337
                         Emicke, Klaus
                         A METHOD  OF  REMOVING SULPHUR  DIOXIDE FROM
                         GAS CONTAINING SULPHUR DIOXIDE. (Nor Deutsche  Af-
                         finerie,  Hamburg, Germany), British  Pat.  1,107,626.  5p.,
                         March 27, 1968. (Appl. June 11, 1965, 12 claims).
                         A method of removing SO2 from exhaust gases is described.
                         The gas is brought into contact with an aqueous solution of
                         selenious acid in reaction vessels through which the solution is
                         passed  in countercurrent to the gas which contains SO2. The
                         removal of the SO2 is performed in two stages. The selenium
                         which is formed in the first stage is removed from the circulat-
                         ing liquor, and the SO2 is completely removed from the gas in
                         the  second stage. It  is  possible to  perform this  method
                         economically and to remove the SO2 completely because  the
                         selenium formed is precipitated in solid form and does not dis-
                         solve in the H2SO4 which is formed simultaneously.

                         13667
                         Lehle, W. W.
                         PROCESSING OF WASTE GASES FROM  SULFURIC ACID
                         PLANTS. In: The  Manufacture of  Sulfuric  Acid,  Werner  W.
                         Duecker and James R. West (eds.),  Am. Chem.  Soc. Mono-
                         graph Series,  New York,  Reinhold  Publishing Corp.,  1959,
                         Chapt. 20, p. 346-358. 25 refs.
                         Tail gases from contact sulfuric acid plants consist mainly of
                         nitrogen, oxygen, carbon dioxide, and a small amount of sul-
                         fur dioxide. Though present normally in small concentrations,
                         sulfur dioxide, sulfur trioxide, and sulfuric acid  can exceed
                         permissible limits during start-ups and plant upset conditions.
                         Sulfur trioxide and sulfuric acid vapor both  form sulfuric acid
                         mists which produce  visible plumes  from  acid plant stacks.
                         Processes for treating tail gases of sulfuric acid plants include
                         scrubbing sulfur dioxide from waste with water, soda ash solu-
                         tions, lime slurries, salt solutions, and ammonia solutions;  the
                         exorption process  developed by the Consolidated  Mining and
                         Smelting  Company; and the  Katasulf  modified autoclave
                         process. As illustrated by the Cominco sulfur dioxide recovery
                         system, an  automated two-stage scrubber method using am-
                         monia solutions  has a number of advantages. It  will reduce
                         sulfur dioxide concentrations in tail gases to 0.03, handle  gas
                         concentrations as  high as 0.9% sulfur  dioxide,  produce a
                         scrubber liquid which has commercial value, and, by eliminat-
                         ing pollution, allow a plant to operate at an overload capacity
                         on the  order of 20%.  Pease-Anthony Venturi scrubbers and
                         Calder-Fox scrubbers are not efficient for sulfuric acid mists
                         less than 10 microns.  Of  the equipment available for mist
                         removal, wire-mesh eliminators and ceramic filters are more
                         effective than cyclone separators, baffles, Vane-type separa-
                         tors,  and  packed-bed  separators.  The costs of  wire-mesh
                         removals is  modest, though the possibilities  of corrosion must
                         be considered in selecting the mesh-wire material. The ceramic
                         filter tube requires considerably more filtering area.

                         13672
                         KENNECOTT STARTS  UP HUGE  H2SO4 PLANT.  Chem
                         Eng. News., 45(13):59-61, 1967.
                         Kennecott Copper's sulfuric acid plant near Salt Lake City is
                         autothermal and designed to run on smelter gas containing 2-
                         6% SO2. Gas from copper converters first goes through a glass
                         cleaning section comprising a Cottrell  precipitator,  a large

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                                           B.  CONTROL METHODS
                                                     11
 Peabody scrubber, and Cottrell mist eliminators. The cleaned
 gas passes through a drying tower, two 2000 hp blowers, and
 into a series of five gas-to-gas heat exchangers before entering
 a three-pass converter where SO2 is converted to SO3. From
 the converter, the gas goes to  the absorbing tower where the
 SO3 is  absorbed  by 98% sulfuric acid. The efficiency of the
 absorption towers is considered to be doubled by the use of 3
 in. interlocked saddles,  which allow a higher throughput of
 gas, and by an increased number of distribution ports for the
 acid that contacts the gas. The mist eliminator installed at the
 top of the absorption tower is a two-stage device with a Teflon
 mesh.

 13728
 Guyot, G.
 PRODUCTION  OF  CONCENTRATED  SULFURIC  ACID
 FROM   SULPHUROUS   GASES  WITH  HIGH   WATER
 VAPOUR CONTENT. (Fabrication d'acide sulfurique concen-
 tre a partir de gaz sulfureux a forte teneur en vapeur d'eau).
 Text in  French. Chim. Ind. (Paris), 101(6):813-816, March 1969.
 Although the contact process is applicable to both dry and wet
 gases, the sulfuric acid produced from wet  gases by this
 method has a relatively low concentration (80%). A process is
 described for producing commercial concentrations (94%) of
 the acid from sulfurous gases with a high content of water
 vapor, even when the sulfur dioxide content is lower than 1%.
 The unit  operating at Lacq is given  as  an example of the
 economics and applications of the process. (Author abstract
 modified)

 13806
 SULFURIC ACID PROCESS REDUCES POLLUTION. Chem.
 Eng. News, 42(40):42-43, Dec. 21, 1964.
 The Bayer process for H2SO4 production is based on a double
 pass of SO2-bearing gases through the converter.  The first
 contact is  accomplished in three stages of varying depths of
 vanadium pentoxide. The  second contact is accomplished in
 the fourth  stage.  The gases increase in temperature from 450
 to 600 C in the first stage and  must be cooled before entering
 the second stage. Cooling is accomplished  by adding a side
 stream of  cold SO2-containing gas to  the reactor just below
 the first stage. A  series of heat exchangers remove the heat of
 reaction in the remaining  three  stages. The SOS-rich gas is
 removed from the  converter  and the S03  is absorbed in
 H2SO4 after the first three stages. The unreacted SO2 is recy-
 cled back through heat exchangers to the fourth stage. Up to
 99.7% of the original SO2  has  been removed after the fourth
 stage. The gas has an analysis of about 0.7% SO3, 0.03%  S02,
 5% O3,  and the remainder nitrogen. The SOS is absorbed in a
 packed tower. Sulfur dioxide sent to the stack is one-seventh
 to  one-tenth   the  concentration  found  in conventional
 processes.

 13880
 Siedlewski, J.
 THE MECHANISM OF  CATALYTIC  OXIDATION ON AC-
 TIVATED CARBON. THE  ROLE OF FREE CARBON RADI-
 CALS IN THE OXIDATION OF SO2 TO SO3. Intern. Chem.
 Eng.,  5(4):608-612, Oct. 1965. 14 refs. (Also: Roczniki Chem.,
39(2):263-271, 1965.)
Free carbon radicals have been  shown to have no influence on
the maximum  quantity  of physically adsorbed SO2;  rather,
they constitute the active centers of the carbon surface in the
chemisorption of  SO2. The quantity of chemisorbed  SO2 in-
creases with a rise in concentration of free radicals on the car-
bon  surface.  If SO2 and O2 are introduced on the catalyst
simultaneously, the increase  in the  mass of the catalyst as  a
result of the  adsorption and  oxidation processes which occur
is found to be proportional to the size of the catalyst surface.
However, the quantity of SOB formed does not depend on the
total amount of adsorbed reactants,  but on the  number of
chemisorbed  molecules. Samples of carbon characterized by
the strongest  signal in resonance spectrum have been found to
have the maximum catalytic activity.

14030
Guyot, G.
S.N.P.A. PROCESS FOR THE TREATMENT OF RESIDUAL
GASES WITH  LOW CONCENTRATION IN SO2.  (Precede
developpe par la  Societe  Nationale des Petroles d'Aquitaine
pour trailer des gaz residuaires charges  de  faibles teneurs de
SO2). Text in French. Chim. Ind.  (Paris),  101(l):31-34, Jan.
1969.
The  sulfuric acid  plant of the Societe Nationale des Petroles
d'Aquitaine at Lacq is able to produce a sulfuric acid with a
concentration of  94% from  gases  containing only  1.5% by
volume of SO2 and  H2S,  and 30% water vapor. The process
involves the oxidation of H2S to SO2, followed by the oxida-
tion  of SO2 to SOS  on a  vanadium catalyst in an adiabatic
reactor, gas-liquid contact in a bed of  Raschig rings, and,
finally,  the absorption of  SO3 by diluted acid circulated and
cooled  in graphite exhangers. After  leaving the  absorption
unit, the gas  is passed through  a Teflon filter which retains
any drops of acid  that are carried along with the gas. To avoid
the condensation  of  acid in the chimney, gases  are lightly
heated  before being  exhausted  into the atmosphere. Gases
emitted from the plant contain 75 mg/cu m SO3 at the most.

14386
Smyslov, N. I.
MEANS  OF  ELIMINATING HARMFUL  WASTES  FROM
SULFURIC  ACID  TOWERS.  (Puti   likvidatsii   vrednykh
vybrosov bashennykh semokislotnykh sistem). Text in Rus-
sian. Ochistka Ispol'z. Stochn. Vod Prom. Vybrosov, Kiev,
Sb., 1964:88-93.
Various causes of instability in tower operation, and hence in-
creases in the amount of harmful wastes above permissible
levels together with a decrease in productivity, are discussed
in general  terms. Measures  adopted in 1954 to normalize
operating conditions and limit each  plant to operation with a
single raw material type were only partially implemented but
did yield positive results; by 1962, the average consumption of
nitrogen oxides per  ton of products for all plants  had been
reduced from 28  kg (1954) to 20 kg; leading plants reduced
HNO3 consumption  to as low as 10 kg. The so-called cross-
reflux  scheme  has  recently been  proven effective and is
recommended for adoption. Conversion to a combined con-
tact-tower system at the Odessa plant has been completed; it
can be applied to plants operating with pure sulfur or pyrite. It
is concluded that sufficient means are available for improving
sulfuric acid systems and  for eliminating harmful wastes;  ac-
celerated implementation is urged.

14533
A METHOD FOR  THE RECOVERY OF NITROGEN OXIDES.
(Werkwijze voor  het winnen van  stikstofoxyden). Text in
Dutch. (Universal Oil Products Co., Des Plaines,  m.) Dutch
Pat. 6,607,036. 13p., Nov.  25, 1966. (Appl. May 23,  1966, 8
claims).

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 12
SULFURIC ACID MANUFACTURING
The system is particularly suited to handling tail gases from a
nitric acid factory and from the lead chamber process of a sul-
furic acid factory. This method also gives a distinct improve-
ment in  the output of  a nitric acid plant. The waste gas is
passed over a bed of adsorbing coal particles followed by a
hot fluid desorption medium to remove the adsorbed nitrogen
oxides from the particles. The desorption medium consists of
steam at about 10 atm at a temperature greater than 157 C and
preferably more than 177 C. The nitrogen oxide-containing
steam is cooled and the mixture obtained is returned to the ad-
sorption zone of the nitric acid plant. The desorption  medium
can  also be  hot air. The depth of the bed should not exceed
0.3m to prevent a large pressure  drop.  The stream waste gas
through the  adsorption bed is  diverted  upon saturation  with
nitrogen oxides to another bed of adsorbing coal. The coal in
the first bed is then desorbed until the second bed is saturated
and  the cycle is repeated. Waste gas from sulfuric acid plants
is treated the same way. The advantages  of this method are
better removal of nitrogen oxides with cost reduction, since no
extra fuel is required. Due  to integration  of the units  for
preparation  of acid and  for recovery,  higher output is  ob-
tained; output of a nitric acid plant can be increased by 5% by
more complete use of NO2.

14568
SafiuUin, N. Sh. and M. I. Olevinskiy
RENDERING HARMLESS THE WASTE GASES FROM SUL-
FURIC  ACID TOWER SYSTEMS. (Obezvrezhivaniye  otk-
hodyashchikh gazov bashennykh sernokislotnykh sistem). Text
in Russian. Khim. Prom. (Moscow), no. 3:132-136, 1955.
It is reported that a complex  consisting of a precipitation sec-
tion irrigated with strong acid and a moist electrofilter will as-
sure reliable purification of waste gases from tower systems.
Such a system reduces the aerosol and vapor sulfuric  acid
content to 0.04-0.10 g/cu m, a 20-fold reduction. Complete ab-
sorption of an equimolar mixture  of nitrogen oxides results in
a reduction in specific consumption rate of nitric acid by 6-8
kg/ton. Absorption of nitrogen oxides and reduction of nitric
acid discharge rate may be increased significantly by supplying
the equipment with nitrogen oxides with a degree of oxidation
of 45-50%. In order to assure normal operation of the equip-
ment, the amount of original sulfuric acid circulating in it must
be not less  than 88%.  Joint  operation  of both the irrigating
system and the electrofilter is imperative for proper purifica-
tion  of waste gases.

14660
Herzog, G.
DESULFURIZATION OF FLUE GASES - PROBLEMS AND
SOLUTIONS.  (Die  Entschwefelung  von  Rauchgasen
Probleme und Losungswege). Text in German. Energietechnik,
17(12):539-542, Dec. 1967. 9 refs.
The  state of the art of desulfurization  methods in East Ger-
many is reviewed. The main emission sources for S02 in East
Germany are the power production plants and the sulfuric acid
industry.  In 1965,  the power plants emitted a total of 685,000
tons of S02. The sulfuric acid plants emitted about 17,500 tons
of SO2 in 1966. No economic desulfurization method yet ex-
ists to cope with these enormous emission quantities. The wet
processes based on absorption of  SO2 by aqueous or  alkaline
suspensions  or  solutions  have three specific  disadvantages.
The gases must be cooled prior to the desulfurization process,
which leads to corrosion problems in the heat exchanger; there
is  a  waste water problem; and the cold, wet gases have no
thermal buoyancy. Due to such problems, industry has turned
to dry methods in recent years. The Reinluft process for ox-
                        idation  of SO2 to sulfuric acid  over an  activated  carbon
                        catalyst has been of prime interest, although it is not economi-
                        cal. A brief outline of the essential principles of this method is
                        given. Oxidation of SO2 to SO3 and subsequent removal of
                        the latter by condensation with water to form H2SO4 or by
                        adsorption on  activated  coal is  mentioned.  Studies  are
                        presently underway in East Germany on the binding of SO2 to
                        alkaline substances such as ash.

                        15739
                        Popovici, N., P. Potop, L. Brindue, and P. Anghel
                        PROPOSED EQUIPMENT FOR RETAINING SO2-CONTAIN-
                        ING RESIDUAL GASES DERIVED FROM THE MANUFAC-
                        TURE OF SULFURIC ACID, IN THE CONTEXT OF A FER-
                        TILIZER  MANUFACTURING  PLANT   AND   UNDER
                        FAVORABLE ECONOMIC CONDITIONS.  (Proiectarea unei
                        instalatii de  retinere  a gazelor  reziduale cu  SO2 de la
                        fabricarea  acidului  sulfuric  in cadrul  unei uzine  de in-
                        grasaminte complexe, in conditii economice avantajoase). Text
                        in Romanian. Rev Chim. (Bucharest), 18(l):40-44,  1967. 17
                        refs.
                        Economic development of  Rumania calls for increasing the
                        production  of  chemical  fertilizers,  including  ammonium
                        phosphate, to 340,000 tons in 1965 and 1,300,000 tons in 1970.
                        The  need for industrial sulfuric acid is also increasing. Am-
                        monia can be used to  remove  SO2 from exhaust gases  and
                        phosphoric acid to decompose the ammonium  sulfite-bisulfite
                        solution. Optimum values, when working with an  SO2 concen-
                        tration of 0.2-0.3%, are a liquid-gas  relationship  of about 3.5
                        per thousand; a SO2/NH3 ratio of 0.7; a maximum and 50 C
                        maximum concentration of ammonium sulfite bisulfite in solu-
                        tion of 700 grams per liter; absorption temperature. Phosphoric
                        acid is used  as decomposing  agent  of the bisulfite  solution,
                        preferably with a gas flow of 75 meters per second. Optimum
                        values to be achieved include: a 50% P205 concentration in the
                        phosphoric acid; an  H3P04/NH3  ratio of  2.2 minimum; an
                        operating temperature of 95  C; and a liquid-gas ratio of .0043.
                        Under these conditions a 90% recovery of SO2 is possible. A
                        device designed to achieve these conditions can process about
                        44,000 Nm3  per hour  of residual gases containing 0.2-0.3%
                        SO2 at a minimum operating cost. This cost (for water, steam,
                        and electrical energy) is offset by the amount of extra sulfuric
                        acid obtained: about 3,500 tons per year.

                        15846
                        Koto, K.
                        REMOVAL OF SULFUR DIOXIDE  FROM EXHAUST GAS.
                        (Haigasu chu no aryusan gasu shori-ho). Text in Japanese.
                        (Toa  Gosei  Chemical  Industry  Co.,  Japan)  Japanese  Pat.
                        174,880.  2p.,  June  6, 1948.  (Appl. Dec. 28, 1943, claims not
                        given).
                        The coal dust and inorganic  compounds (SiO2, Fe2O3,  A1203,
                        CaO) resulting from  coal gas production are used to remove
                        sulfur dioxide  gas from factories  engaged in sulfuric acid
                        manufacture.  This coal  dust is activated by the high tempera-
                        ture, oxygen, and steam, and shows a tremendous adsorptive
                        power for SO2. In addition,  the inorganic compounds included
                        in large amounts with the coal dust (40.23 to 57.96%), neutral-
                        ize the SO2 present in  the water. Thus, 600 1 of coal dust is
                        homogenized  with  1.7  1 of water and  is scattered inside  a
                        cylinder in which SO2 (0.7% of the total exhaust gas) passes at
                        the rate  of 135 cu m/min. The washed exhaust  gas includes
                        only 0.04% of SO2 at a  temperature of 12 C. The coal dust can
                        be used in this procedure for 48 hrs.

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                                           B. CONTROL METHODS
                                                     13
 15879
 IMPROVEMENTS IN OR RELATING TO A PROCESS FOR
 RECOVERING SULPHUR DIOXIDE  FROM A  GAS MIX-
 TURE CONTAINING THE SAME.  (American Smelting and
 Refining Co.,  New York) British Pat.  564, 734. 5p., Oct. 11,
 1944. (Appl. June 29, 1942, 16 claims).
 In a cyclic process for recovering sulfur dioxide from smelter
 smoke, flue gases, etc., sulfur dioxide-containing gas is first
 absorbed in an aromatic  amine reagent  of the aniline class and
 its homologues and derivatives preferably dirnethylaniline. The
 exit gases are then scrubbed with sodium carbonate and sul-
 furic acid solutions to remove the reagent, following which the
 resulting solutions' are  combined and heated by  steam to
 release the  sulfur  dioxide and the regenerated amine esters.
 The released reagent is returned to absorb additional sulfur
 dioxide. While various types of scrubbers may be employed in
 the  process, best  results are  obtained with  bubble  towers.
 Compared to other processes, the operation greatly reduces re-
 agent losses and regenerative costs.

 15991
 Fleming, Edward P. and  T. Cleon Fitt
 RECOVERY OF  SULPHUR  DIOXIDE FROM  GAS MIX-
 TURES. (American Smelting and Refining Co., New York) U.
 S. Pat. 2,295,587. 3p., Sept. 15, 1942. (Appl. Nov. 25, 1939,  7
 claims).
 A cyclic process  for recovering sulfur dioxide from  smelter
 smoke, flue gases, and the like uses  an aromatic amine as the
 reagent absorbant. Compared to other methods,  the process,
 which  preferably  takes  place in  a  bubble  tower,  greatly
 reduces reagent losses and regenerative costs. Sulfur dioxide-
 bearing gases, after cleaning to remove nongaseous contami-
 nants,  are  passed  to the bottom of an absorber  where they
 flow upward in countercurrent to the absorbent,  preferably
 dimethylaniline. Within  the  absorber,  the  sulfur  dioxide is
 transferred from the gas mixture to  the dimethylaniline, with
 the efficiency  of the transfer enhanced by controlled cooling
 of the  absorber. The sulfur dioxide-depleted gases are passed
 through sodium carbonate and sulfuric  acid solutions and
 steam  is added to  free the gases from the regeant. The aro-
 matic  amine and sulfur  dioxide mixture is passed through  a
 heat exchanger on  its way to the stripping tower. The excess
 steam  and  reagent vapors are  brought into contact with the
 aromatic amine and sulfur dioxide mixture to expel the latter
 and  yield a warm stripped reagent. The  stripped  reagent is
 further cooled  and separated into  two components, mainly
 water  and  reagent. The anhydrous  reagent is returned for
 treating additional volumes of sulfur dioxide-bearing gases.

 16289
 Yeselev, I. M., I. P. Mukhlenov, and D. G. Traber
 CERTAIN QUESTIONS ABOUT THE OPERATING REGIME
 OF A  COMBINED CONTACT-TOWER SYSTEM.  (Nekoto-
 ryye voprosy  rezhima  raboty kombinirovannoy  kontaktno-
 bashennoy  sistemy).  Text in Russian.  Zh.  Prikl. Khim., vol.
 37:1204-1210, May-Aug.,  1964.13 refs.
 Analysis  of data from  the literatures  showed that optimum
 temperatures in the  preliminary catalytic oxidizing arrange-
 ment with a fluidized catalyst bed are subject to the same de-
pendences as in arrangements with  a stationary bed. Formu-
lated calculations  indicate that a system producing 315,000
tons of sulfuric acid per year is economically feasible with  a
preliminary oxidation arrangement using an iron oxide catalyst
with a particle size  ranging from 0.80 to 1.30 mm.
16290
Yeseleve, I. M., I. P. Mukhlenov, and D. G. Traber
USE  OF  DION CATALYST IN  THE  CONTACT-TOWER
PROCESS. H. (K voprosu ispol'zovaniya zheleznogo kataliza-
tora v kontaktno-bashennom protsesse). Text in Russian. Zh.
Prikl. Khim., vol. 37:972-979, May-Aug., 1964. 14 refs.
The rate  of  sulfur dioxide oxidation in a reactor  with a
fluidized iron oxide catalyst bed is reduced as compared with
a reactor with a stationary layer. The  degree of reduction in
rate is characterized by the ratio of contact  time required  to
achieve a given degree of conversion  in a fluidized catalyst
bed to the analogous contact time for a stationary layer, all
other conditions being equal. Empirical formulas derived for
determining this ratio  are shown to describe the kinetics  of
SO2 oxidation in an arrangement with  a fluidized catalyst bed
with sufficient accuracy. Verification on a pilot installation has
demonstrated complete suitability of these equations for desig-
ning industrial reactors.

16291
Lastochkin, Yu. V., I. P. Mukhlenov, I. G. Lesokhin, Ye. S.
Rumyantseva, and T. P. Bondarchuk
OXIDATION OF SULFUR DIOXIDE IN AN ARRANGEMENT
WITH A  PSEUDO FLUIDIZED  BED  OF HtON OXIDE
CATALYST UNDER CONDITIONS OF CONTACT-TOWER
PRODUCTION OF  SULFURIC ACID.  (Okisleniye semistogo
gaza v apparate  s  psevdoozhizhennym sloyem okisnozhelez-
nogo katalizatora  v usloviyakh  kontaktno-bashennogo  proiz-
vodstva  semoy  kisloty).  Text in Russian.  Khim.  Prom.
(Moscow), 42(6):45-48, 1966. 4 refs.
Optimum conditions for sulfuric acid production in a pseudo
fluidized bed of an iron oxide catalyst  were studied on both a
laboratory and industrial scale. Data indicated that, with a sul-
fur dioxide content of 12% at an optimum temperature of 680-
700 C, there is a sharp rise in catalyst productivity with an in-
crease in volumetric gas flow rate. With a constant linear gas
flow rate, there is a resultant decrease  in hydraulic resistance
of the system and an increase in the volumetric flow rate,  at
the same time, a minimum required degree of preliminary ox-
idation is assured.  Increasing the  volumetric flow rate also
reduces catalyst  consumption to five times below existing
systems using vanadium catalysts.

16447
Tamm, O. M.  and E. M. Vasil'eva
MEASURES FOR REDUCING ATMOSPHERIC  POLLUTION
IN CTITES OF THE ESTONIAN SSR. (Meropriyatiya po sniz-
heniyu zagryazneniya atsmofernogo  vosdukha v  gorodakh
Estonskoy  SSR). Text in Russian. In: Sanitation  Measures
Against Air and Water Pollution in the  Planning of Cities. (Oz-
dorovleniye  vozdushnogo  i vodnogo  basseynov  gorodov).
Government Committee  on Civil Building and Architecture
(ed.), Lecture series no.2, Kiev, Budivel 'nik,  1968, p.39-40.
Air pollution problems in Estonia center around the cities of
Tallinn and Kohtla-Jarve. A  paper and pulp  plant, a sulfuric
acid plant,  a mineral-enriching installation, and  a   shale
processing combine are cited as major air pollution sources  in
the Kohtla-Jarve area and some of the measures  taken to con-
trol these sources are mentioned. Control measures widely in-
stituted in the country include:  conversion to gas and liquid
fuels, the use  of central heating plants, removal from the cities
of large pollution sources such as asphalt-concrete plants, and
the closing of installations which do not lend  themselves to air
pollution control (e.g., the stone crushing facility at the Tallinn
concrete plant, and the asphalt-concrete plant  at Toyl).

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14
SULFURIC ACID MANUFACTURING
16480
Boreskov, G. K., L. G. Rimmer, and E. I. Volkova
IGNITION TEMPERATURE  OF  VANADIUM  SULFURIC
ACID CATALYSTS.  (Temperature zazhiganiya  vanadievykh
sernokislotnykh katalizatorov)  Text  in  Russian.  Zh. Prikl.
Khim., 13(3):250-260,  1949. 7 refs.
A thermographic method of determining the ignition tempera-
ture of the catalytic mass was developed and verified. The ig-
nition temperature of sulfuric acid-vanadium catalysts was ex-
perimentally determined for gas mixtures containing from 7-
95%  sulfur dioxide and 5-75% oxygen at initial degrees of
catalysis of 0 to 50%. It was shown that a change in the igni-
tion temperature of vanadium catalysts in relation to the com-
position of the gas was dependent on the shift of the tempera-
ture  of  the  phase  transformation  of the catalytically active
polyvanadates  into  vanadyl sulfates and with a change in the
reaction rate.  Equations  are  proposed and a diagram con-
structed for determining  of the ignition temperature of  gas
mixtures of varying composition. At a constant concentration
of oxygen, the ignition temperature was practically indepen-
dent  of the sulfur dioxide concentration. With an increase in
oxygen concentration, the ignition temperature decreased.  For
gas obtained by roasting pyrites and containing 7% sulfur diox-
ide and 11% oxygen, the ignition temperature was 423 C. For a
stoichiometric  mixture (66.7% sulfur dioxide, 33.3% oxygen),
the ignition  temperature equalled 394  C. An increase in the
degree of  catalysis to 50% increased the ignition temperature
20-30 deg. A decrease in the activity of the vanadium catalysts
as a result  of terminal treatment  or  lengthy processing in-
creased  the  ignition temperature which was directly  propor-
tional to the logarithm of the ratio of thyinitial and final values
of the reaction rate constant. The  temperature of extinction
was determined for gas mixtures containing 7% sulfur dioxide;
11%  oxygen and 50% sulfur dioxide; and 50% oxygen. At a
hypothetical linear gas flow rate equal to 0.15 m/sec, the tem-
perature of extinction in the first case was 7  deg  and in the
second,  85 deg below  the temperature of ignition. The  dif-
ference  in the temperatures of ignition and  extinction cor-
responded well with the difference in surface  temperature of
the grains in the first layer of catalyst and gas, calculated ac-
cording to the rate of heat loss. This  indicates that catalytic
oxidation of sulfur dioxide is carried out entirely at the surface
of the catalyst.

16718
Remirez, Raul
DOUBLE-ABSORPTION  GETS U.S.  FOOTHOLD.  Chem.
Eng., 76(2):80-82, Jan. 27, 1969.
The first sulfuric acid plant in the Western Hemisphere to use
a double-absorption process will soon be constructed. The
process has been popular in Europe not only for its antipollu-
tion properties but also because the higher conversion  (99.5%)
results in attractive  raw-material savings. However, installation
and operating costs still appear to be substantially higher than
for single absorption units. When sulfur emission control laws
are enacted it is probable that single absorption plants now in
existence will find it desirable to either convert to the double
absorption process or improve the efficiency of the present in-
stallation.  Some of  the possible avenues open to improve the
single absorption units are discussed.

17053
Connor, John M.
NEW METHOD REDUCE AIR POLLUTION IN OLDER SUL-
FURIC ACID PLANTS. Water Sewage Works, 117(1):IW/16-
IW/19, Jan.-Feb. 1970.
                         There are a large number of plants in operation and in good
                         shape,  producing large quantities of acid,  which were  not
                         designed according to current conversion standards and which
                         cannot, without modification, meet the proposed new air pol-
                         lution standards. Many of the smaller plants will probably be
                         shut  down, but  the larger plants in good condition can be
                         modified. Two schemes are offered for removing the sulfur
                         dioxide from sulfuric acid plant stacks. Flow charts are given.
                         A modified version of the first scheme could be designed to
                         suit roaster gas plants  in some cases, but the problem in con-
                         nection with these plants  is much more  complex and each
                         plant would have to be  considered individually. The second
                         scheme is simpler to install in an existing plant, and can poten-
                         tially increase the total output of the plant by 10 to 20% and
                         improve conversion at the same time. By taking advantage of
                         the fact that the double absorption process is usually operated
                         with  10% SO2 in the converter feed, compared to 8% in the
                         standard plant, scheme 2 could be used to increase production
                         by as much as 35%.

                         17810
                         Srbek, Josef, Rostislav Klimecek,  and Lubomir Jager
                         PROCESS OF RECOVERING SULFUR DIOXIDE FROM EX.
                         HAUST GASES.  (Zpusob  zachycovani kyslicniku siriciteho z
                         odpadnich plynu). Text in Czech. (Assignee not given.) Czech.
                         Pat.  108093.  3p., Aug. 15, 1963. (Appl.  Nov.  15,  1958, 2
                         claims).
                         A process of recovering sulfur dioxide during the last stages of
                         sulfuric acid manufacture  is presented. The exhaust gas is
                         channelled to the absorption device, where a solid compound
                         of zinc is in water suspension. The process is characterized by
                         using only that amount of the water suspension  of zinc oxide
                         or hydroxide  which corresponds  to the  amount of the  ab-
                         sorbed SO2 from the exhaust gases. To prevent solidifying the
                         suspension,  a  very diluted suspension below 3% of the total
                         amount of zinc should be used.

                         17887
                         Garbato, Carlo
                         PROCEDURE  FOR CATALYTIC  OXIDATION OF  SUL-
                         FUROUS  GASES, NO MATTER  HOW PRODUCED, AS A
                         MEANS OF MANUFACTURING SULFURIC ACID AND OLE-
                         UM, USING CATALYSTS DISPERSED AS A FINE DUST IN
                         THE  REAGENT GAS  AND  CmCULATTNG   WITH   IT:
                         MEANS AND DEVICES FOR ITS APPLICATION.  (Procedi-
                         mento per 1'ossidazione catalitica  di gas solforosi, comunque
                         prodotti, per la fabbricazione  di acido solforico ed oleum a
                         mezzo di catalizzatori dispersi in povere fine nella massa gas-
                         sosa reagente, e con essa fluenti mezzi e  apparecchiatura  per
                         realizzarlo). Text in Italian. (Assignee not  given.) Italian Pat.
                         435,452. 3p., May 18, 1948. (Appl.  April 11, 1946, 6 claims). In
                         the process of making  sulfuric acid from sulfurous gases,  the
                         principle of  a  'flowing'  rather  than a  'static'  catalyst is
                         preferred, wherein the catalyst is pulverized to a suitable parti-
                         cle size and is circulated directly with the gas itself throughout
                         the apparatus. This avoids the problem, encountered with the
                         stationary catalyst, of the accumulation of heat in the catalyst,
                         which if not dissipated in some way or other causes  the reac-
                         tion temperature to rise, disturbing the relationship of SOS to
                         SO2,  thereby reducing the  yield of sulfuric acid. The preferred
                         catalyst is an iron oxide produced by roasting powdered iron
                         pyrite. The pyrite roasting and the SO2 oxidation take place in
                         the same apparatus,  the iron oxide produced being  used  im-
                         mediately as catalyst for the oxidation of SO2. Catalysis takes
                         place in a special apparatus consisting of a metal chamber,
                         which is cooled by the  circulation  of some type of fluid which

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B.  CONTROL METHODS
                                                                                                                  15
 absorbs excess heat produced by the reaction. The apparatus
 is constructed  so as  to resist  pressures above  atmospheric
 pressure. A partial catalysis may also be performed with a cir-
 culating catalyst  wherein the process  is  completed  with the
 conventional 'static' process.

 17889
 Roesner, Gerhard
 UTILIZATION OF INDUSTRIAL AND RESIDUAL GASES BY
 THE METHODS  OF THE LURGI ENTERPRISES. (L'Utilisa-
 tion de Gaz Industrials et  Residuels  par  les Precedes des
 Societes Lurgi). Text in French. Metallges. Periodic Rev., no.
 13:22-31, 1938. 8 refs.
 The modern  trend in  the  chemical   industry is  to  utilize
 processes in which the chemical reactions  take place in the gas
 phase. This raises the problems  of cleaning gases prior to their
 reaction, as well as of  processing the residual gases of that
 reaction. The Lurgi enterprises address themselves to the task
 of providing engineering solutions to these kinds of problems,
 including processes of purification  of reacting gases of sub-
 stances which  'poison  the catalyst' used to accelerate or  to
 make possible the desired reaction  and processes of remove!
 of dust and  other participate solids, of condensable vapors,
 and  of gaseous constituents  from the residual gases, with the
 objective of their recovery or of prevention of their discharge
 into the atmosphere. Various devices and existing  industrial in-
 stallations  are reviewed, such as 'Multiklon'  centrifugal dust
 separators, electrostatic  filters for removal not only dry dusts
 but also condensable mists, scrubbing towers for  selective ab-
 sorption of  gases  or  mists by liquid absorbents  and the
 'Benzobon' process of absorption by solid charcoal of benzene
 from city gas or coking-plant gas. A large  section  of the paper
 is devoted to the removal of sulfur  dioxide  and hydrogen sul-
 fide from waste  gases,  the  production of ammonium  sulfate
 and particularly the production of sulfuric  acid.

 19033
 Roll, Kempton H.
 CONTROLLING CORROSIVE AIR POLLUTANTS. J. Air Pol-
 lution Control Assoc., 1(6):6-10,  May 1952.
 Control of  an aerosol, such as sulfuric acid mist,  is a problem
 of collection, but an entirely different  technique must be util-
 ized in the case of a gas such as sulfur dioxide. Conversion  of
 SO2 to  H2SO4 is a possibility,  as is absorption of the gas  in
 chemicals  from which  it can  be  recovered  as pure SO2.
 Hydrogen sulfide is now being treated in a number of oil
 refineries by burning it  in air to convert  it to sulfur dioxide
 and  water  vapor  or by  burning it in  the presence of sulfur
 dioxide  to convert it to elemental sulfur and water vapor. It is
 common practice to add  an electrostatic precipitator at the end
 of the processing circuit through which all gases  bearing sul-
 furic acid  mist must  pass.  As  the gases pass  through the
 precipitator, they  receive electrical charges which cause them
 to coalesce, whereas the  sonic collector operates on the princi-
 ple  that high intensity sound will cause particulate  matter  to
 agglomerate and descend to  the bottom for removal. One of
 the newest and most successful methods of converting sulfur
 dioxide  to  liquid  involves dissolving the  impure  gas  in  cool
 dimethylaniline  and extracting it as  pure  SO2 by heating the
pregnant dimethylaniline  solution.

 19228
Drechsel, Herbert, Karl-Heinz Doerr, and Hugo Grimm
METHOD  FOR THE CATALYTIC OXIDATION OF SO2 TO
SO3  IN  SO2  LADEN GASES AND  PRODUCTION  OF SUL-
                 FURIC  ACID.  (Verfahren zur katalytischen Oxydation  von
                 SO2 in  SO2-haltigen Gasen  zu SOS und Herstellung  von
                 Schwefelsaeure). Text in German.  (Metallgesellschaft A. G.,
                 Frankfurt (W. Germany))  Swiss  Pat. 478,712. 4p.,  Sept. 30,
                 1969. (Appl. Oct. 25,1963, 5 claims).
                 A method for the catalytic oxidation of sulfur dioxide in SO2-
                 laden gases to  SOS with the  aid of oxygen containing gases
                 and  production of sulfuric acid by absorption of the formed
                 SOS is  described.  The SO2-laden  gases are heated by heat
                 exchange with the formed SO3 containing gases. The SO2 con-
                 tent  in the gases is increased prior to catalytic  oxidation by
                 mixing with gases from the combustion of sulfur. The inven-
                 tion  pertains to the use of primary gases with an SO2 content
                 at 9% or less by volume. The hot gases from the combustion
                 of sulfur are mixed at least with part of the heated flow of pri-
                 mary gas after it has left the  heat exchanger and prior to the
                 entrance into the catalytic oxidation chamber. The sulfur and
                 oxygen quantities must be selected so that the sum of the heat
                 developing at the combustion of sulfur to S02 plus the heat
                 developing at the oxidation of  SO2 to SOS suffices to compen-
                 sate  for  the heat loss suffered at the intermediate absorption
                 of SOS. The sulfur dioxide content  of the mixture of primary
                 gas/sulfur combustion gas may not  exceed 9% by volume. A
                 branch of non-heated SO2 containing primary gas is added to
                 this  gas mixture to obtain a temperature of 440 C (maximum).
                 If the  primary gas  contains less than 9% SO2, 3  to  4  kg,
                 preferably 3.5 kg, sulfur per 1000 cu m primary gas are burned
                 for each  missing percentage and added to the gas.

                 19370
                 Ganz, S. N., I. E. Kuznetsov, V. A.  Shlifer, and L. I. Leikin
                 REMOVAL OF NITROGEN  OXIDES, SULFUR DIOXIDE,
                 MIST, AND SULFURIC ACID SPRAY FROM EXHAUST GAS
                 BY PEAT-ALKALI SORBENTS UNDER PRODUCTION CON-
                 DITIONS.  J. Appl. Chem.  USSR  (English translation from
                 Russian of: Zh. Prikl. Khim.), 41(4):700-704, April  1968. 1 ref.
                 Optimal  conditions  were determined for the  absorption of
                 nitrogen  oxides, sulfur dioxide, mist, and sulfuric acid  spray
                 from sulfuric acid tower systems by means of peat-alkali ab-
                 sorbents. Shredded peat with  a moisture content up to 50%
                 was  used for absorption; solid ash,  apatite concentrate,  aque-
                 ous  ammonia, and ammonia gas were used as additives to the
                 peat. The moisture content of the peat in the  absorber must
                 not be below 25-30%, as at lower moisture contents the peat
                 begins  to form dust  and  the  absorption process deteriorates
                 considerably. Ammonia  introduced  directly to  the  fluidized
                 beds was the most effective  additive, removing 90% of  the
                 acidic components of the waste gas  in 90 min. For 80% purifi-
                 cation of the gas in one hr, it  is sufficient to have one or two
                 beds with a total sorbent height of  about 500 mm. A sulfuric
                 acid  plant  with a gas output of up to 60,000 cu m/hr will
                 require 0.294 tons ammonia, 1.5 tons of dry peat, and 3 tons of
                 peat  (with a moisture content of 50%) per hr for gas decon-
                 tamination. Sorption of the gases by the peat-ammonia sorbent
                 yields an effective organomineral fertilizer.

                 19383
                 SO2  ABSORBER:  TWO  SCRUBS BETTER  THAN  ONE.
                 Chem. Eng., 62(2):132-134, Feb. 1965.
                 Sulfur dioxide in concentrations as high as 0.9% is effectively
                 removed  from sulfuric acid plant fumes in a double scrubbing
                 tower that comprises two separate  scrubbers built one above
                 the other. The  scrubbing system utilizes  ammonium sulfite-
                 bisulfite solutions. Inlet gases  pass  countercurrent to the first
                 scrubbing solution in the  lower scrubber,  where most of the
                 sulfur dioxide is recovered. Gas then moves through a chim-
                       ^  .,
     LIBRARY

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 16
SULFURIC ACID MANUFACTURING
ney to the upper section, where a weaker solution removes the
remaining sulfur dioxide. Tail gases discharged  to  the at-
mosphere contain less than 0.3% sulfur dioxide. Ammonium
sulfate is recovered as a  by-product by passing the solution
from  the lower scruober to a stripping tower and reacting  it
with sulfuric acid from the acid unit. The ammonium sulfate  is
pumped to an adjacent fertilizer plant.

19469
Woollam, J. P. V. and A. Jackson
THE  REMOVAL  OF  OXIDES OF SULPHUR FROM EXIT
GASES.  Trans. Inst. Chem.  Engrs. (London), vol. 23:43-51,
1945.  33 refs.  (Presented  at  the Institution of Chemical En-
gineers North Western Branch Meeting, Manchester, England,
March 17, 1945.)
A process is described for removing sulfur dioxide and triox-
ide from the exit gases of contact acid plants, boiler installa-
tions, and smelting processes. It consists  of scrubbing the
gases with a  solution of ammonium  sulfite, bisulfite, and
sulfate  mixture,  keeping  the pH value at a predetermined
figure by the addition of  aqueous ammonia, and bleeding off
the make of solution to an autoclave where it is heated with
steam to form ammonium sulfate solution and sulfur. On the
basis  of encouraging preliminary tests, a large-scale process
facility  was built at a contact acid plant. Testing  and results
are given in detail, and permit definition of the limits for op-
timum conditions. The SO2 and SOS present in the exit gases
can be reduced to less than 5% of their original value, and the
price  of the ammonia feed can be reduced to 60% of that for
the pure 25% ammonia by the use of 18-20% concentrated gas
works liquor.  Two applications  of the process  are briefly
discussed: acid plant exit  gas treatment, and 'devil gas' treat-
ment  with reference to a 15% hydrogen sulfide  gas mixture.

19486
Hara, Maruichi
RESEARCHES ON CONTACT REACTION RATE FOR SO2-
OXTOATION. Ann. Genie  Chim., 1967:187-196, 1967. 6 refs.
The velocities  of contact reaction rates for sulfur dioxide ox-
idation over vanadium pentoxide-industrial catalyst were mea-
sured for both forward and  reverse reactions using a dif-
ferential reactor. For gas phase reactions, an approximate rate
formula of catalytic reaction was derived theoretically in case
of the reactions being in  stationary state and  having no side
and no  consecutive reactions. Results of applying the derived
formula to the experimental  data and to many  reactor designs
for sulfuric acid factories  in Japan were satisfactory. (Author
abstract modified)

19592
Takeuchi, Tsugio and Tamotsu Tanaka
DRY  REMOVAL  PROCESS  OF SULFUR COMPOUNDS IN
EXHAUST STACKS. Translated from Japanese. Franklin Inst.
Research Labs., Philadelphia, Pa., Science Info. Services, 3p.,
Oct. 29,  1969.
The  ability of activated  charcoal to remove sulfur dioxide
from  exhaust gas  in the form of  sulfuric acid was tested by
passing  the treated gas through a hydrogen  peroxide solution
and titrating by alkali the H2SO4 that was produced in the
solution. The amount of sulfur dioxide entrained by the char-
coal varied greatly with the linear velocity of the gas and with
space velocity. In addition, activated charcoal wetted with am-
monium  sulfate captured  about three times as  much sulfur
dioxide as the original activated charcoal. Presumably, the sul-
furic  acid produced on the  charcoal reacts with  ammonium
                        sulfate to yield ammonium hydrosuifate and to free sulfuric
                        acid not produced on the charcoal. The experiments demon-
                        strate that ammonium sulfate can be used to regenerate the ac-
                        tivated carbon and that crystallized ammonium sulfate can be
                        easily recovered as a by-product.

                        19593
                        Chemical Construction Corp., New York, N. Y., Consulting
                        Div.
                        A BD3LIOGRAPHY OF REMOVAL OF NITROGEN OXIDES
                        FROM  WASTE  GASES, EXCEPT METHODS BASED  ON
                        REDUCTION AT HIGH TEMPERATURE AND CATALYTIC
                        DE-COMPOSITION,  1907-1968,  WITH ABSTRACTS.  (PART
                        4). In: Engineering Analysis of Emissions Control Technology
                        for Sulfuric Acid Manufacturing Processes. Volume 2. Litera-
                        ture Search. Contract CPA 22-69-81,  52p., March  1970.  158
                        refs. CFSTI: PB190471
                        References and abstract from U. S. and foreign sources, in-
                        cluding patents, are arranged and indexed by a variety of in-
                        dividual  adsorption and absorption control methods, within
                        one  of  two major  subdivisions. Part One  pertains  to  the
                        removal of nitrogen oxides from chamber and Mills-Packard
                        sulfuric acid plant tail gases, while Part Two is concerned with
                        the removal of low concentrations of nitrogen oxides from
                        waste gases.

                        19594
                        Chemical Construction Corp.,  New York, N. Y., Consulting
                        Div.
                        A BD3LIOGRAPHY OF SULFUR TRIOXTOE AND SULFURIC
                        ACID MIST EMISSIONS AND THEm CONTROL, 1907-1968,
                        WITH ABSTRACTS.  (PART  3). In: Engineering Analysis  of
                        Emissions Control Technology for Sulfuric Acid Manufactur-
                        ing Processes. Volume 2. Literature Search. Contract CPA 22-
                        69-81, 32p., March 1970. 105 refs. CFSTI: PB 190471
                        References and abstracts from U. S. and foreign sources, in-
                        cluding  patents,  are  arranged and  indexed by subject into
                        seven major categories. These are: sulfuric acid mist forma-
                        tion; physical  behavior of H2SO4 mists;  sulfuric  acid mist
                        emissions and  their control; mist removal in general; sulfuric
                        acid mist removal;  sulfur trioxide removal;  and  analytical
                        methods.

                        19595
                        Chemical Construction Corp.,  New York, N. Y., Consulting
                        Div.
                        A BIBLIOGRAPHY OF SULFUR DIOXIDE REMOVAL AND
                        RECOVERY FROM  WASTE  GASES AND SULFURIC ACID
                        PLANT TAIL GASES, EXCLUDING THE LIMESTONE AND
                        DOLOMITE INJECTION PROCESSES, 1953-1968, WITH AB-
                        STRACTS. (PART H). In: Engineering Analysis of Emissions
                        Control   Technology  for   Sulfuric   Acid   Manufacturing
                        Processes. Volume 2. Literature Search. Contract CPA 22-69-
                        81. 58p., March 1970. 223 refs. CFSTI: PB 190471
                        References and abstracts from U. S. and foreign sources, in-
                        cluding patents, are arranged and indexed by subject within 13
                        major categories. These are:  data on SO2 emissions; toxicity
                        and tolerance of SO2 in the atmosphere; absorption of SO2 in
                        water; absorption of SO2 in inorganic  aqueous salt  solutions;
                        aqueous  slurries; sorption  by solid materials; molten salts;
                        aqueous solutions of organic compounds; oxidation of  SO2 to
                        SO3; removal of SO2 by reduction; chromatographic  separa-
                        tion; general reviews and  economic aspects;  and  bibliogra-
                        phies. Several tables of data on SO2 air pollution are also in-
                        cluded.

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                                            B. CONTROL METHODS
                                                      17
 19606
 Burgess, Wilfred Duncan
 TREATMENT OF FLUE GASES. (Consolidated Mining and
 Smelting Co. of Canada, Ltd., Montreal (Quebec))  U. S. Pat.
 2,862,789. 8p., Dec.  2,  1958. 8 refs. (Appl. May 17, 1954,  4
 claims).
 A method of economically recovering sulfur from  flue gases
 which  contain  very small  amounts  of  sulfur  oxides  is
 presented. The process  employs ammonium sulfate as an ab-
 sorbing agent, and involves a series of cooling and concentrat-
 ing steps and treatment with sulfuric acid. Previously, in ap-
 plying  this absorption process to the treatment of gases from
 combustion  furnaces, a number of difficulties were  encoun-
 tered,  such  as: high  cost of cooling gases to the desired tem-
 perature, problems with fly ash acting as condensation nuclei,
 and evaporation  of large quantities of water in order to avoid a
 very dilute concentration of ammonium sulfate. These difficul-
 ties are successfully overcome by the process described.

 19644
 Tsudo, Kozaburo
 OPERATION  OF  SO2  GAS ABSORBING PLANT.  Nippon
 Kokan Giho  (Tokyo),   19(1): 1-6,   1966.  Translated  from
 Japanese Belov and Associates, Denver, Colo., 19p., April 21,
 1970.
 A method for controlling sulfur emissions from a sulfuric acid
 plant is described. This method is a limestone-gypsum injec-
 tion where  the  sulfurous acid  gas and sulfur  dioxide  are
 neutralized, and the gypsum  is  recovered.  Lime  milk  is
 sprayed into an elimination tower where the SO2 and acid are
 absorbed. The solution containing SO2 is sent  to a pH tower
 where  it is regulated to a suitable  pH by an acidification reac-
 tion. Calcium sulfite, formed in the elimination tower, is sent
 to an acid tower. Here it is acidified to calcium  sulfate to form
 gypsum by minute mist. The gypsum is transported to a gyp-
 sum thickener where it is separated, washed, and deliquidated.
 The operation and production data of this system are also in-
 cluded.

 19682
 Amelin, A. G.
 CONDENSATION OF SULPHURIC ACID. Ann. Genie Chim.,
 1967:52-61, 1967. 12  refs.
 The process of  sulfuric acid condensation is  complicated by
 several concurrent  processes  which are  specific  for  the
 production  of sulfuric  acid. Therefore,  proper corrections
 should  be  introduced  into average calculation  formulae.
 Moreover, sulfuric acid  vapor is easily condensed in  volume,
 forming a stable  mist which causes great difficulties  in produc-
 tion processes.  When a vapor-gas mixture  contacts a colder
 surface, two independent processes occur simultaneously cool-
 ing of  the gas and condensation  of the vapor. The rates of
 these processes  are in  such a relation that at  the  beginning,
 vapor  oversaturation increases, reaches the maximum value,
 and then goes down. When oversaturation reaches the critical
 value,  the vapor condenses in  volume forming nuclei which
 later increase because of condensation growth. While consider-
 ing the process  of vapor condensation on  the surface,  it is
 necessary to differentiate strictly between conditions before
 and after mist formation. In the first case, the process of con-
 densation can be calculated according to well-known formulae,
in the  second case a stage-by-stage method of calculation is
 used. The results of investigations  show that  the  necessary
data are  available for establishing such condensations under
which  the formation of mist can be eliminated.  However, this
is usually  connected  with the  decrease  of condensation
process rate. Therefore it often appears very profitable to con-
duct the process at high rates with the formation of larger
drops of mist and then to remove that mist in filters. Minimum
material expenses for the realization of the process are deter-
mined by vapor condensation on the surface and by the condi-
tions of mist evolution in filters. (Author abstract modified)

19856
Postnikov, V. F. and T. I. Kunin
ON THE RECOVERY OF SO2 FROM WASTE GASES FROM
CONTACT  SULFURIC-ACID  PLANTS.  (K  voprosu  Iz-
vlecheniya  SO2  iz otkhodyashchikh gazov kontaktnykh Ser-
nokislotnykh  zavodov).  Text  in Russian.  In: Tr.  Ivanovsk.
Khim. Tekhnol. Inst., no. 2, p. 56-70, 1939.
The use of a quinoline-water  mixture as a sulfur dioxide ab-
sorber was studied experimentally,  and a 1:1 ratio was found
to be optimum.  Absorption was significant, but neither the
degree of SO2 accumulation,  nor the frequency  of regenera-
tion, were determined. Studies were made at 20-100 C with gas
mixtures containing 0.7% SO2 and 0.2-0.3% SO3, and with gas
flow rates ranging 0.09-0.24 m/sec.

19886
Bacon, Raymond F. and  Isaac Bencowitz
RECOVERY OF SULPHUR.  (Raymond F.  Bacon) U.  S. Pat.
1,917,234. 5p., July 11, 1933. (Appl. July 29, 1930,  11  claims).
In various processes suggested for recovering elemental sulfur
from roaster gases, the sulfur dioxide gases are usually  treated
at some point removed from their source. This results  in loss
of the sensible heat of the gases, and the necessity of supply-
ing supplemental heat to replace the lost heat. A process is
described for recovering elemental  sulfur from SO2 gases in
which the high sensible heat of the gases is retained, and addi-
tional heat is derived from the  furnace itself. The hot gases are
first sent to a collector to remove any fine dust entrained in
the SO2.  The  cleaned  gases  are  passed  into the reaction
chamber where they are contacted  with a reducing  gas, such
as natural gas, water gas, or producer gas. The temperature of
the reducing gas is raised when it is mixed with  the hot SO2
gases, and by absorption  of heat from the burner. The reaction
between the S02 and the reducing gas is rapid and  exothermic.
As the gases leave the  chamber they are  cooled in a waste
heat boiler, and treated with an electrostatic precipitator or by
absorption to remove  the sulfur. The residual gases may be
catalytically oxidized to  remove hydrogen sulfide and recover
additional sulfur.

19943
Grodzovskiy, M. K.
MECHANISM OF CATALYTIC  OXTOATION OF SO2 IN A
SOLUTION OF MANGANESE SALTS. H.  THE EFFECT OF
OZONE ON MANGANESE SALT SOLUTIONS.  (Mekhanizm
kataliticheskogo okisleniya SO2 v rastvore solei margantsa. II.
Deystviye ozona na rastvor zaMsnoy soli marganitsa). Text in
Russian. Zh. Fiz. Khim.,  vol. 6:496-510, 1935.
Studies of sulfur dioxide  oxidation in manganese salt solutions
have led to the following conclusions: SO2 concentrations of
0.3-0.4% do not provide sufficient conversion of Mn-2 to Mn-3
when  used  as the catalyst in  amounts of about  5%; low O2
partial pressure  (5-10%)  in the flue gases  also hampers  this
conversion, or  renders  it nonexistent with poor absorption
equipment; as acidity increases, alpha 02 decreases to  30-40%
sulfuric acid,  and the rate of induced oxidation diminishes to
zero due to inhibition of  complex formation, oxidation, and to
a drop in regenerative capability of  the catalyst resulting from

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18
SULFURIC ACID MANUFACTURING
formation of stable Mn2(SO4)3; increasing catalyst concentra-
tion above 0.025% has no further effect, especially when the
oxygen partial pressure is low; increasing the solution volume
in itself yields no improvement; negative catalysts poison the
manganese; the action of ozone is necessary to counteract the
above factors so as to maintain manganese activity; gradually
increasing  the ozone concentration maintains oxidation and
regeneration up to a practical H2SO4 level  of 50% (60-65%
maximum) even with low  SO2 and O2 concentrations; ozone
should lead both  to accelerated oxidation of MNSO2 and to
direct oxidation of Mn-2; these  and other effects of ozone
form a basis for evaluating the use of ozone to produce con-
centrated sulfuric acid  from flue  gases;  since SO2 oxidation
proceeds by means of Mn oxidation, perhaps more economical
means are possible, such as electro-oxidation.

20024
Yeselev, I. M., I. P. Mukhlenov, and D. G. Traber
USE  OF IRON  CATALYST  IN  THE  CONTACT-TOWER
PROCESS. (K voprosu ispol'zovaniya zheleznogo katalizatora
v kontaktno-bashennom  protsesse). Text in Russian. Zh.  Prikl.
Khim., vol. 37:722-727, Jan.-April 1964. 22 refs.
Equations were verified  for calculating the contact time of gas
on an iron catalyst that were sufficient to yield a given degree
of  conversion. Sulfur dioxide was oxidized over  a  stationary
iron catalyst layer with a grain size of 0.75 mm. The gas flow
rate was 0.975 m/sec and rate constants were determined over
the range 610-730 C. Estimations  of the energy of  activation
were about 126 kJ/mole for temperatures above 640 C, and 280
kJ/mole below 640 C. The discountinuity at 640 C  is explained
by the conversion of active ferric oxide to the inert sulfate.
The literature is reviewed with respect to the reaction kinetics
for SO2 absorption on  an iron catalyst  with both  stationary
and fluidized beds.

20248
Public Health Service, Cincinnati, Ohio, National Air Pollution
Control Administration
A STATUS REPORT: PROCESS CONTROL  ENGINEERING;
R & D FOR AIR POLLUTION CONTROL. 37p., Nov. 1969.
The various phases of the work of the Process  Control En-
gineering Division of the National Air Pollution  Control Ad-
ministration are described as of late 1969. These include sulfur
oxides control (dry and wet limestone processes, coal clean-
ing, and  new processes such as those employing molten  alkali
carbonates), industrial process control (nonferrous smelting,
iron and steel,  sulfuric  acid, papermaking, graphic  arts, iron
foundries,  aluminum smelting, etc.),  combustion  emissions
control (e.g.,  fluidized-bed combustion,  nitrogen  oxides), ap-
plied equipment research (wet scrubbers, fabric filters, electro-
static precipitators, incinerator control),  supporting measure-
ments (detection,  spectroscopy, dust and gas-sampling analy-
sis, holographic determinations,  continuous  monitors,  etc.),
and advisory and  supporting services. A special report is also
given on the alkalized alumina process for control of SO2. A
list of 110  specific research projects and 11 services is given.
More than  eleven  million dollars was budgeted for the Process
Control Engineering programs in 1969. The 1970 budget is ex-
pected to  be  more  limited, necessitating  an emphasis on
sustaining rather than new programs.

20416
(Inventor not given.)
PROCEDURE  FOR  PRODUCTION OF  SULFURIC ACID.
(Precede de production  d'acide sulfurique).  Text in French.
                         (Mitsubishi shipbuilding and  Engineering Co., Ltd., Japan)
                         French Pat. 1,348,923. 7p., Dec. 2, 1963. (Appl. Feb. 28, 1963,
                         5 claims.)
                         Two procedures are presented for producing sulfuric acid from
                         a gas  containing sulfur oxides and from a suspension. In the
                         first case, the gas is brought into contact  with  an  aqueous
                         suspension of a manganese oxide, of a concentration  at which
                         it remains fluid, to form MnSO4.  If the latter reacts with HC1,
                         H2SO4 and a crystalline precipitate of MnC12 are formed. In
                         the presence of O2 and H2O vapor at an elevated temperature,
                         MnC12 decomposes into HC1  gas and a Mn oxide, which are
                         returned to the operations of H2SO4 formation and MnC12
                         precipitation and of preparation of an aqueous suspension of a
                         Mn oxide. In the second case, from an aqueous suspension of
                         crystalline MnSO4, a gas  containing hydrochloric acid is in-
                         troduced into the aqueous suspension at a temperature not ex-
                         ceeding 50 C  and,  preferably,  at  ambient temperature  to
                         produce H2SO4  and  crystalline  MnC12. After separating the
                         latter  from H2SO4, it is reacted with a gas containing O2 and
                         H2O vapor at a temperature  between 350  and 600 C  in order
                         to oxidize  it to HC1 and a Mn oxide. The resulting gas contain-
                         ing hydrochloric acid  is re-used for production of MnC12 from
                         MnSO4. In addition,  a hot gas  containing hydrochloric acid
                         produced in the oxidation of MnC12 is used to eliminate HC1
                         remaining  in H2SO4 after its separation from MnC12.  This gas
                         is cooled in an indirect heat exchanger by transferring its heat
                         to H2SO4, yet to undergo the HC1 elimination treatment.  Air
                         is brought into contact with the HCl-bearing H2O condensate
                         of that heat exchanger to obtain air containing HC1 and H2O
                         vapor to be used for MnC12 oxidation.

                         20670
                         Furkert, Herbert
                         METHOD  OF   RECOVERY   OF   SULPHURIC   ACID.
                         (Chemiebau Dr. A. Zieren  G.m.b.H. and Co. K. G., Cologne-
                         Braunsfeld (West Germany)) U. S. Pat.  3,490,868. 5p., Jan. 20,
                         1970. 4 refs. (Appl. March 4, 1968, 6 claims).
                         Sulfuric acid is produced from sulfur dioxide-containing gases
                         by a multi-stage catalytic oxidation process and  a two-stage
                         sulfur trioxide absorption. The  first absorption  stage  is ar-
                         ranged before the last oxidation stage and the second absorp-
                         tion stage is arranged after  the  last  oxidation stage. Sulfur
                         trioxide-free  exhaust  gas leaving  the first  absorption stage is
                         reheated to  the  starting temperature for the last oxidation
                         stage with superheated steam. The steam is obtained  from an
                         exothermic step of the overall sulfuric acid  recovery process
                         starting with a sulfur containing raw material.  (Author  ab-
                         stract)

                         20777
                         Tamura, Zensuke and Yukio Hishinuma
                         A  PROCESS AND APPARATUS  FOR  THE DESULFURIZA-
                         TION  OF INDUSTRIAL  WASTE GASES.  (Hitachi,  Ltd.,
                         Tokyo (Japan)) U. S.  Pat. 3,486,852. 6p., Dec. 30, 1969. 4 refs.
                         (Appl. Sept. 21, 1967,  20 claims).
                         A process and  apparatus for desulfurizing industrial waste gas
                         and recovering sulfuric acid as a byproduct are described. A
                         portion of the  waste  gases are introduced into an adsorption
                         tank to remove the sulfur oxides  by contacting them  with ac-
                         tive carbon, while the remaining portion is  sent to a region for
                         drying the active carbon which has been wet in a proceeding
                         rinse-desorption step.  From the drying  tank the gases are led
                         to  the adsorption tank. Waste gases free of  sulfur oxides are
                         released to the atmosphere from  the adsorption stage. Sulfur
                         oxides are removed from  the active carbon by rinsing with

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                                            B. CONTROL METHODS
                                                      19
 water, and the washings are removed and sent to a concentra-
 tion tank where they are heated and sulfuric acid is recovered.
 The functions of the respective regions is the  adsorption-
 desorption apparatus are shifted one after another at a certain
 time interval, so  that a cycle of operation  consisting of adsorp-
 tion, rinsing-desportion and drying, is carried out concurrently
 repeatedly.

 21309
 Argenbright, L. P. and Bennett Preble
 SO2 FROM  SMELTERS:  THREE  PROCESSES  FORM AN
 OVERVIEW OF RECOVERY COSTS. Environ.  Sci. Technol.,
 4(7):554-561, July 1970.
 About 2.2 million long tons per year of sulfur is contained in
 the sulfur oxide gases generated in the operation of copper,
 zinc,  and lead smelters in  the western United  States.  Nearly
 23% of this is recovered, mostly as sulfuric acid. A study was
 made to identify and evaluate the technological  and economic
 problems  associated with controlling  the sulfur oxide emis-
 sions of these smelting operations. Three processes for control
 and by-product recovery were considered: the contact sulfuric
 acid process, the Cominco absorption process, and the ASAR-
 CO reduction process. All three are adversely affected by the
 low percentage of sulfur in the exhaust gases. Similarly, all are
 limited in optimum size, since the capital investment for larger
 operations off-sets  the  reduction in  operating  cost.  Of the
 three processes considered, the contact sulfuric acid process is
 the least  costly,  both in terms of initial cost  and operating
 cost.

 21203
 Romovacek, Jiri  and Jaroslav Fohl
 APPARATUS FOR THE PREPARATION  OF GASEOUS MIX-
 TURES WITH LOW SO2 CONCENTRATION. (Apparatur zur
 Herstellung  von  Gasgemischen mil  kleiner SO2-Konzentra-
 tion). Text in German. Erdoel Kohle (Hamburg),  23(5):294-296,
 May 1970. 13 refs.
 A gaseous mixture with sulfur dioxide  concentrations of 0 to 1
 mg/cu m is obtained by continuously adding dichlorsulfitomer-
 curate-(II) to sulfuric acid  and by diluting the  liberated SO2
 with a regulated flow of carrier gas. The solution of dichlorsul-
 fitomercurate-(II) is pumped peristaltically into a spiral-shaped
 glass  column  simultaneously  with  the  H2SO4.  The  spiral
 column has an inner  diameter of 8 mm  and a  length of 800
 mm. The carrier gas nitrogen is taken from a pressurized gas
 bomb, and is cleaned with solid NaOH. The speed of the carri-
 er gas is controlled  by a manometer. A constant SO2 concen-
 tration was produced in long-term experiments.

 21824
 Chemical Construction Corp., New York, N. Y.,  Consulting
 Div.
 ENGINEERING   ANALYSIS   OF  EMISSIONS  CONTROL
 TECHNOLOGY  FOR SULFURIC ACID  MANUFACTURING
 PROCESSES. Contract CPA 22-69-81, 276p., March 1970. CF-
 STI: PB 19093
The capabilities  and  state  of  development of  the  available
processes  and devices to effect control for both existing and
new plants were  evaluated to determine the cost of control by
various methods, and to outline programs  for further develop-
ment  of  systems which appear to have  the greatest  overall
potential for reducing undesirable emissions from sulfuric acid
plants in the United States  at the lowest cost. Existing plants
can  reduce  their  emissions  somewhat  by  modifying  their
operating  conditions with  little capital expenditure,  but this
control is limited to about 2000 ppm of sulfur dioxide. Present
technology can achieve a control effectiveness of 500 ppm of
SO2 via the dual absorption route, and excellent acid mist con-
trol in the order of 0.1 mg/SCF. No fully developed acid plant
control systems are commercially operated in the U.  S. which
achieve an effectiveness of  100 ppm of  S02, but there are
promising ones in various stages of development. It is doubtful
that there is any contact plant in the U. S. to which some type
of control system could  not be applied to  reduce emissions to
less than 500 ppm SO2, but  to do so economically may be a
different story. Cost of emission control varies widely with
plant capacity, type of control system and other factors. Cost
of less than 500 ppm SO2 control for a 250 T/D contact plant
varies from about $.75 to over $3 per ton of acid. Mist control
costs vary from  $.02 to $.35/tons  of  acid. These costs are
predicated  on an asssumption that promising processes will
work as expected.  Control  cost is lower for  large plants.
Recommended areas for study include development  of resin
and molecular sieve adsorbents, oxidation inhibitor  develop-
ment for tail gas recovery processes, study of stack dispersion
and  factors affecting it, plus development work on several
processes, both for treatment of tail gas and improved in-plant
conversion.

22055
Snowball, A. F.
A CYCLIC PROCESS  OF SULPHURIC  ACID MANUFAC-
TURE AT  TRAIL,  B. C. Can. Chem.  Process, vol.  31:1110-
1114, Dec. 1947. 2 refs. (Presented at the  C.I.C. Meeting,
Banff, Ontario, June 8-11, 1947.)
In a  cyclic process of sulfuric acid production, pure sulfur
dioxide and oxygen are fed to a circulating gas stream that is
moved by  centrifugal blowers  through  heat exchangers  to
cylindrical  steel converters packed  with  vanadium  catalyst.
The converted gas containing sulfur trioxide at high tempera-
ture  is first cooled in the heat exchangers, then in air-cooled
pipes before entering absorber towers where  the sulfur triox-
ide is removed in contact with 98.4% sulfuric acid. The cycle
is complete when the gas passes through  spray  catchers and
coke  filters back  to the blowers. Measured quantities of ox-
ygen  and 100% sulfur dioxide gas are added during and after
absorption, replacing sulfur trioxide and bringing the  gas con-
centration back to the ideal operating percentages of 25% sul-
fur dioxide,  30% oxygen,  and 54%  nitrogen.  Control  of
catalyst temperature in  the converter is reviewed,  as are the
steps taken to prevent metal corrosion. Efficiency of the plant,
which is operated by one  attendant through  centralized con-
trol, is 99.5%.

22182
(Inventor Not Given.)
METHOD  OF   REGENERATING  ADSORBING  COKES
CHARGED WITH SULFURIC ACID. (Precede de regeneration
de cokes adsorbants charges d'acide  sulfurique).  Text  in
French. (Bergwerksverband G.m.b.H.,  Essen, W. Germany)
Belg.  Pat. 707,739. 9p.,  June 10,  1968. (Appl. Dec. 8, 1967. 4
claims).
A method is described for the regeneration of adsorbing cokes
charged with sulfuric acid after having served  to fix sulfur
dioxide obtained from gas containing SO2 in  the presence of
oxygen  and water vapor.  The adsorbing  coke charged with
H2SO4 is first washed in the known manner by means of hot
water or of aqueous solutions. Between  1  and 5% (by weight)
sodium or potassium hydroxide is added to the wet coke and
the coke is heated in an inert atmosphere at a  nominal 600-
1000 C (400 C minimum) for 1/2 4 hours. The thermal  treat-
ment includes simultaneous rinsing by means of an inert gas.

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 20
SULFURIC ACID MANUFACTURING
22943
Hammond, Roll
ELIMINATING DUST  IN CHEMICAL PLANT. Chem. Age,
(New York), vol. 77:431-433, March 9, 1957.
Among new equipment for eliminating dust from chemical
plant flue gases is a multi-wash collector that removes  sub-
micron particles with maximum efficiency. The collector com-
prises  a cylindrical stainless steel tower with six and one-half
vaned  impingement stages. An entrainment separator  placed
above  the units forms a seventh tier. Air enters the tower just
below  its conical base,  which acts as a wet cyclone to  collect
the heavier particles upon entry. A water curtain descending
from the top of the tower combines with spray  and impinge-
ment to envelop the particles rising with the air, carrying them
down into the cone and out of the collector. When most of the
dust is above  the  submicron range,  collectors with  fewer
stages  are employed. These collectors are equally effective on
both soluble and insoluble dusts and on soluble gases. For the
removal  of gaseous  contaminants such  as hydrogen sulfide,
sulfur  dioxide,  hydrochloric or hydrofluoric acid vapors, al-
kaline  solutions are added to the recirculated liquid. For the 0.1
to 5 micron particles found in pharmaceutical and bacteriologi-
cal work,  an esparto grass-based paper filter with asbestos
fibers  has an efficiency of 99.95%. This filter can be accom-
modated in a very  small place. A reverse-jet type filter has
proved very efficient for  vaporized silica of  0.6 micron and
less. Electrostatic precipitators are used to remove dust and
fumes  from pyrite  roasters,  sulfuric  acid  mist  from  wet
catalyst sulfuric acid plants, and sulfuric acid mist from  coal
roaster gases. Static rectifiers for the precipitators  are  availa-
ble that dispense with  the high-tension connections formerly
required. Alternating current is rectified and used without
high-frequency  effect on  the wave-form, as  in the case of
mechanical rectifiers.

23048
TIME  TO  RETHINK SULFURIC  SOURCES. Chem.  Week,
102(19):55-56, May 11, 1968.
Slightly more than  a year ago, engineers agreed  that while
chemical process technology is readily available  to make sul-
furic acid  from pyrite  concentrate or gypsum,  the methods
could not compete economically with sulfuric from elemental
sulfur. However,  the handicaps associated with pyrites  and
gypsum are beginning to disappear, now that the price  of sul-
fur is $42 per long ton. Total plant investment costs are com-
pared  on the basis of 400,000 short  tons of acid per year
produced  from brimstone,  pyrite,  and  gypsum.  For each
method, the total plant investment is equal to  125% of the bat-
tery-limit costs. Total indirect costs are  16.6% of the entire
plant investment. The economics of the gypsum process are
expected to become more attractive with the development of a
fluid-bed process for recovering sulfur from calcium sulfate in
the form of waste gypsum. There are two steps to the process:
first, dry gypsum is preheated in a fluid bed and the two mols
of combined water are driven off at a temperature high enough
to support combustion of residual hydrocarbons; secondly, the
calcium sulfate is reduced in a second chamber to calcium sul-
fide  at approximately 1560 F. The latter is recovered as  a
suspension  in water, where it is carbonated with  carbon diox-
ide gas to yield  calcium carbonate and  also sulfur in the form
of hydrogen sulfide gas. The gas is burned with air to form the
sulfur dioxide gas feeding the sulfuric acid plant.
                         23070
                         Averbukh, T. D., I. A. Apakhov, O. V. Maydurova, N. P.
                         Bakina, N. P. Blinova, A. A. Burba, and I. V. Avdeyeva
                         REMOVAL  OF SULFUR FROM  COPPER-SULFUR PLANT
                         WASTE  GASES   BY  THE   AFTERBURNING  METHOD.
                         (Ochistka otkhodyashchykh gazov mednosernyk zavodov ot
                         sery metodom dozhiganiya). Text in Russian. Khim.  Prom.
                         (Moscow), no. 4:51-58, 1962. 7 refs.
                         Catalytic afterburning of waste gases containing about 3 vol.
                         % carbon disulfide, carbon sulfide, hydrogen sulfide, and sul-
                         fur  dioxide (50 g/cu m of sulfur) to produce sulfuric acid was
                         studied experimentally at temperatures of 200-600 C using 16
                         different catalysts. Data are given for the following catalysts:
                         various types of bauxite, barium-aluminum-vanadium (BAV),
                         and chamotte treated with nickel and aluminum nitrates. Pilot
                         studies made at flow  rates of 800-1200  cu m/h using bauxite
                         and BAV catalysts are reported, and a proposed production in-
                         stallation is described.

                         23264
                         Adachi, Noriyoshi, Makoto Kimura, and Seiko Hashimoto
                         ELECTRIC  FILTRATION OF SO2. Taiki Osen Kenkyu (J.
                         Japan Soc. Air Pollution),  2(1):98-100,  1967. Translated from
                         Japanese. 8p.
                         To develop equipment for the removal of sulfur dioxide in flue
                         gas,  a wet-type electric precipitator was constructed  and  a
                         basic study of electric  filtration of  SO2 was performed. Liquid
                         was dropped along the inside wall of a glass cylinder of 35 mm
                         inner diameter. The corona electrode was placed  at the center
                         of the cylinder and voltage was applied between the corona
                         electrode and the liquid surface. A  known concentration of
                         SO2 gas  was introduced from the bottom of the cylinder,
                         passed through the corona discharge, and was taken out from
                         the  top of the  cylinder.  Sampling  of SO2 was in accordance
                         with Japan Industrial Standard JIS-KO103-1963;  titration was
                         employed for the  analysis of SO2. As SO2 is an electronega-
                         tive gas on which electrons are easily attached,  its collection
                         efficiency was increased at a corona starting voltage  of 5 kV
                         and the efficiency was constant with voltages larger than  a
                         certain value. The  collection efficiency was always higher with
                         a negative corona electrode voltage than with a positive one.
                         With positive voltage above a certain level, collection was not
                         achieved steadily.  A flow rate of about 100 ml/min. was most
                         adequate. Gas collection efficiency was greater than 95% with
                         an applied voltage of 9 kV  and SO2 concentration  below
                         0.45%. In the preceding results, water was employed as the
                         collection medium. Further experiments were conducted using
                         a 5% aqueous solution of Na2CO3 and a 10% aqueous solution
                         of sulfuric acid. The collection efficiency  was reduced with
                         the  increase  of  SO2  concentration; this  tendency was  more
                         pronounced with the sulfuric acid solution. With a voltage of 7
                         kV,  the efficiency with the  Na2CO3  solution  was  almost
                         100%, whereas with the sulfuric acid solution it was only 35%.

                         23556
                         Clauss, N. W.
                         THE REDUCTION OF ATMOSPHERIC POLLUTION FROM
                         SULFURIC  ACID RECOVERY PROCESSES.  Manufacturing
                         Chemists Association,  Washington, D. C. Air Pollution Abate-
                         ment  Committee  and Manufacturing Chemists  Association,
                         Washington,  D. C., Water Pollution Abatement Committee
                         Proc. Mfg. Chem. Ass. 1952-53 Pollution Abatement Conf., 9p.
                         Effluent gases from air-blown sulfuric acid concentrators con-
                         tain sulfuric  acid  mist and sulfur  dioxide resulting from the
                         decomposition  of   sulfuric acid by  carbonaceous materials

-------
                                            B.  CONTROL METHODS
                                                      21
 present in the spent acid. A pflot plant was designed to study
 the removal of the mist by low-pressure water sprays, high-
 pressure water sprays, bag filters, and decomposition by heat
 When the data obtained suggested that the high-pressure water
 spray  system was most effective,  a plant-scale acid mist
 removal unit was  put into  service. The sulfuric acid mist
 removal of  the plant-scale unit appears to be higher than the
 efficiency obtained in the pilot spray unit, probably due to the
 elimination  of wall effects. It is concluded that when the full
 capacity of  the system is made available, the system can be
 operated, at a net operating cost (1953) of $5000 year, at max-
 imum production rates with no pollution of the atmosphere by
 sulfuric acid mist.

 23939
 Nagibin, V.  D.
 SMELTING   CONCENTRATES  IN  CONVERTERS  AND
 PRODUCTION OF SULFUR DIOXIDE FOR SULFURIC ACID
 MANUFACTURE.  Soviet J.  Non-Ferrous  Metals  (English
 translation from Russian of: Tsvetn. Metal.), vol. 9(10):39-42,
 Oct. 1968.
 Industrial tests were performed on the converter smelting of
 copper  matte in an air blast enriched with up to 24-27% ox-
 ygen. The  output  capacity of converters  increased  propor-
 tionally to the percentage of oxygen in a blast. The tempera-
 ture of  the molten charge in converters increased sharply as a
 result of the heat of exothermic reactions; this permitted the
 processing of cold  additions in the form of ore, concentrate,
 and other copper containing materials.  Concentrations  of sul-
 fur dioxide  in the waste gases  of the converter increased by
 1.5-2.5% (in absolute value),  varying during  the second blow-
 ing period by 5-10%. The operating  regime of the converters
 decreased markedly when enriched blasts were used during the
 first and second blowing stages. On the basis of these findings,
 programs were developed for the smelting of pelletized copper
 concentrates and  for the production of sulfuric acid from con-
 verter waste gases alone. The latter process is based on a
 starting concentration  of about 4%  SO2 in converter waste
 gases fed to a contact-reaction vessel and on  special condi-
 tions for matte   blowing. At least two converters are con-
 tinually  on  blast,  the blast consumption  of  each  varying
 between 30,000 to 45,000  cu m/hr. Before being passed to the
 sulfuric acid production plant, the exhaust gases are pressure
 fed by a blower  to electrostatic dust separators. An automatic
 switching system  for changing the direction of the gases from
 the sulfuric  acid  units to stack exhaust makes it possible to
 stabilize the content of sulfur  dioxide being shipped  to the
 former.

 24103
 Browder, Timothy J., Jr.
 METHOD OF SULFURIC ACID MANUFACTURE. (Parsons
 (Ralph M.) Co., Los Angeles, Calif.)  U. S. Pat. 3,525,587. 4p.,
 Aug. 25, 1970. 3 refs. (Appl. July 19, 1968, 12 claims).
 A process is described for the production of sulfuric acid by
 the catalytic oxidation of sulfur  dioxide containing gas and the
 multiple stage absorption of sulfur trioxide produced by such
 catalytic oxidation.  Sulfur dioxide  containing gas  can  be
produced by a variety of reactions, such as by the oxidation of
hydrogen sulfide or hydrocarbon mercaptans, or by metallurgi-
cal smelting. Conventional multiple oxidation stage processes
which utilize intermediate absorption between stages are defi-
cient in that they fail to allow the desired flexibility of initia-
tion of optimum inlet or exit temperatures for each of the ox-
idation stages. The present method utilizes a portion of the ex-
othermic reaction heat  of gas exiting from the first of at least
three successive oxidation stages, having an intermediate ab-
sorption  stage between the second  and third stages for pre-
heating gas passing into the  third oxidation  stage. Exit gas
from the first oxidation stage is preferably  split into two
streams;  one stream is fed to a heat exchanger for pre-heating
gas  to be  fed into the first  oxidation stage,  and the other
stream is utilized to pre-heat gas passing from the intermediate
absorption  stage to the third oxidation stage.

24110
Berly, Edward M., Melvin W.  First, and Leslie Silverman
RECOVERY OF  SOLUBLE GAS AND AEROSOLS  FROM
AIR STREAMS. Ind. Eng. Chem., 46(9):1769-1777, Sept. 1954.
18 refs.
High efficiency absorption of soluble or reactive gases was ob-
tained with wetted fiber beds. Wetted fibers were five to  10
times more efficient than Raschig rings or  Berl saddles, com-
pared on the basis of equal volumes. When compared  on the
basis of  weight of packing, 1 pound of  78-micron-diameter
saran fibers was 75 times more effective for the absorption  of
hydrogen fluoride gas than  1 pound of 1/2 inch Berl saddles.
In addition to hydrogen fluoride gas,  cleaning efficiency for
sulfuric  acid  and ammonium bifluoride  mists,  ammonium
bifluoride and aluminum chloride  fumes, and silica, tale, and
atmospheric dusts was investigated. High efficiency collection
(greather than 99.9%)  generally  required  the  addition of a
droplet eliminator  composed of  a 1 to 2-inch  depth  of dry
fibers less than 5 microns in diameter.  Although absorption  of
the  gas  was  complete,  a  significant  quantity of fluorides
passed the scrubber in  the form of fine (less than 10 micron)
mist droplets formed from condensation of hydrogen fluoride
gas  in the humid  atmosphere  of the  scrubber  or from fine
droplets  formed by the sprays. When  gas  streams containing
inert particles were treated, the absorbing stages were pro-
tected from fouling and plugging by the use of an impingment
device such as a Neva-Clog screen as  a prefilter. Over-all re-
sistance of the scrubber was proportional to the flow rate. For
gas flows of 200 cu ft/min, sq ft  of scrubber face area, high
efficiency scrubbing of gas and submicron paniculate  matter
was obtained with resistances not exceeding 6 inches of water
gauge  For  atmospheric pollution control of stack gas, emis-
sions resistances less than half this may be adequate. (Author
summary)

24246
Farrar, G. L.
LACQ LEADS IN SULFUR-RECOVERY OPERATIONS. Oil
Gas J., 68(42):72- 75, Oct. 19, 1970. 2 refs.
Already the largest single producer of  chemically derived sul-
fur in the world, and with one of the  largest gas throughputs
anywhere, the Lacq gas processing plant in southern France is
now the  leading pioneer  in recovering sulfur from plant ex-
haust  gases.  The  air-pollution-prevention attack is  three
pronged.  The sulfur plants are automated to insure that  sulfur-
content of  effluent gases from Claus sulfur units is at  an ab-
solute minimum. A sulfuric acid plant, operating on a part  of
the sulfur-plant off gas, makes  a  salable product and reduces
the sulfur content in  the effluent gas to the hundreds of ppm
range. A new sulfur recovery process, operating on another
part of Claus off gas, utilizes a special catalyst, which is active
at reactive conditions  and  low  operating temperatures  to
drastically cut the concentration of sulfurous gases in  the ef-
fluent. In the new (Sulfreen)  process, the feed gas  is first
cleaned by contacting it with liquid sulfur, then passed to a
battery of six reactors where Claus reactions are carried out at
temperatures lower than those utilized in the sulfur plant.

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22
SULFURIC ACID MANUFACTURING
These  temperatures insure that product  sulfur deposits are
deposited on the catalyst as  a liquid. A stream of nitrogen
sweeps the  catalyst clean while the liquid  sulfur product  is
drained off to liquid storage. The feasibility of installing other
Sulfreen units is being studied.

24256
Yashke, Ye. V., A. G. Amelin, V. A. Petrovskiy, and V. A.
Osmul'kevich
GLASS-FIBER FILTERS  FOR TRAPPING SULFURIC ACID
MIST.  (Steklovoloknistyye fil'ty dlya ulavlivaniya tumana ser-
noy  kisloty). Text in Russian.  Khim. Prom.  (Moscow), no.
3:196-200, March 1965. 16 refs.
The  use of alkali glass fibers as filter material for the collec-
tion  of sulfuric acid mist was studied experimentally for sul-
furic acid concentrations of 75-98%, with mist droplets 0.2-0.5
micron in diameter.  Procedures  for estimating degree of
deposition as a function of droplet size, mist density, gas flow
rate, gas viscosity, fiber  diameter, and  filter packing density
are discussed. Data on the operation of such a  filter in an in-
dustrial installation in combination with  an electrofilter are
presented. This filter handles  10,000-15,000 cu  m of mist per
hour, effecting 99.7% removal.

24451
Petersson, Stig
CONCENTRATING SULFUR-CONTAINING GASES  FROM
SMELTING PLANTS. (Koncentrering av svaveldioxidhaltiga
smaeltverksgaser).  Text in Swedish. Kem. Tidsskr., 82(1):34-
38, Jan. 1970.
Copper, lead, and zinc are usually present in nature in sulfide
ores. When these ores are processed by industrial operations,
gases containing sulfur dioxide are liberated. The SO2 concen-
tration varies depending upon the  process. A primary control
method for S02 involves  absorption of the gas by water or an
organic solution, followed by healing and condensing to liquid
SO2  for  sulfuric  acid manufacturing.  A Swedish plant  is
described which produces liquid SO2 from smelter plant gases.
The  plant capacity is 50,000 cu m/hr at 4.5% SO2. The liquid
SO2  is partly sold and partly used to raise the gaseous SO2
content at a sulfuric acid plant.  The  absorption tower  is
designed for an efficiency of 98% calculated at maximum load
and at  a water temperature of 11 C. The plant raises  the use of
SO2  in the gases from the smelting plant from 75% to 95%.
The  plant was motivated by both production efficiency and en-
vironmental concern.

24594
Rosendahl, Fritz
RECENT  PROCESSES FOR THE REMOVAL OF SULFUR
COMPOUNDS  FROM  GASES,  AS  SEEN  IN  GERMAN
PATENTS FOR THE YEAR 1964. (Neuere Verfahren zur Ent-
fernung von  Schwefelverbindungen aus Gasen-dargestellt an
Hand deutscher Patent von 1964).  Text in German.  Gas Was-
serfach (Munich), 106(31):857-859, Aug. 6,  1965.  19 refs.
German patent  literature is reviewed, summarizing achieve-
ments in the field of dry gas removal, wet ammonia processes
and  other wet processes, reactions between hydrogen sulfide
and  sulfur dioxide, and the removal of organic  sulfur com-
pounds. An iron oxide is obtained from the roasting of pyrite,
the fine granular form of  which can absorb 93.3% S. One am-
monia process, making use of waste water from a coke plant,
gives a 70-80% sulfuric acid yield. Wet processes use not only
water but also various organic solvents such as methanol, pyr-
rolidone, or piperidone. The advantage  of the  two last-men-
                         tioned solvents is their relatively high boiling point. Acetone,
                         methanol, or ethanol can also be added to the water used in
                         scrubbers (5-20 vol.  %), reducing the viscosity and making
                         possible a lower operating temperature. Hydrogen sulfide and
                         carbon monoxide can  be  removed from waste gases under
                         pressure  by using various esters  and ester mixtures.  The
                         removal of organic sulfur compounds can be achieved with an
                         efficiency of at least 90%. The removal of hydrogen sulfide
                         from gases by the use of activated charcoal requires a pore
                         diameter of more than 60 A, while the removal of organic sul-
                         fur compounds requires a diameter on the order of 20-40 A.

                         24628
                         Drechsel, Herbert, Karl-Heinz Doerr, and Hugo Grim
                         PRODUCTION  OF  SULFUR  TRIOXTOE AND  SULFURIC
                         ACID. (Metallgesellschaft A. G., Frankfurt (W. Germany)) U.
                         S. Pat. 3,525,586. 7p., Aug. 25, 1970. (Appl. Oct. 12, 1966, 4
                         claims).
                         A catalytic oxidation  process is described which utilizes sulfur
                         dioxide-containing gases to produce sulfur trioxide and sulfuric
                         acid. The SO2 content of the gas must be at least 9% in order
                         for this process to work. The process involves  a series of heat
                         exchange  and  oxidation steps  and a hot  single  stage inter-
                         mediate  absorption step. It is self-sufficient as to sensible heat
                         requirements, actually producing recoverable excess heat to be
                         utilized  for  other purposes.  The advantages of this process
                         over previous ones are that the initial concentration of S02 in
                         the starting gas can vary over a specified range, and that this
                         process  produces excess heat  while other processes require
                         heat inputs to function properly. This process results in a high
                         degree of conversion, making it economically desirable.

                         24673
                         Asano, Toyoshi
                         DISPOSAL OF  WASTE GAS CONTAINING  DELUTE SUL-
                         FUR OXIDE. (Kihaku sanka iou ganyu gasu no kaishu). Text
                         in Japanese. Kogyo  Kagaku Zasshi (J.  Chem.  Soc.  Japan),
                         73(7):1731-1732, July 5,  1970. 3 refs.
                         Disposal  of  sulfur  dioxide in pyrites  roasting, petrochemical
                         industry, or  power plant waste gas is discussed. In a conven-
                         tional wet disposal method, SO2 is merely neutralized by an
                         agent like lime or ammonia, but a very large  quantity of  the
                         neutralization agent is  needed. Another  disadvantage of  the
                         conventional method is that its sulfur oxide absorption effi-
                         ciency  drops with  substances  formed  as a  result  of   the
                         neutralization process. When SO2 gas was made to flow coun-
                         tercurrent to manganese ore suspension in a tower, SO2  was
                         reduced  to sulfuric acid of a densit about the same as that  ob-
                         tained in a lead chamber method, and practically no SO2  was
                         contained hi the gas  discharged from the tower. A 10% man-
                         ganese-ore suspension was used in an experimental device in
                         which the suspension was  heated to the desired temperatures
                         and,  when vaporized by the heating,  automatically reduced
                         from  gas  to   liquid.   Ore  composed   of  Mn(27.96%),
                         SiO2(37.32%), Fe(8.16%) and P(0.03%) was pulverized to  80-
                         mesh grains and mixed with water at a 10:90 ratio to make the
                         suspension used  as the absorbing agent.  From the results of
                         this test, it was determined that the higher temperature of the
                         suspension,  the  higher its SO2  absorption  efficiency;   the
                         amount  of SO2 absorbed  decreased with  increasing sulfuric
                         acid density in the suspension; at 50 C, the quantity of sulfuric
                         acid contained in the suspension reached 74.3 g/100 ml.  The
                         contact time of SO2  gas with the suspension was 5.7 sec and
                         the gas injection speed 8 cm/min. The device maintained about
                         100% SO2 absorption efficiency for 20 hrs, indicating that the
                         manganese oxide  suspension can  be  effectively used as an
                         SO2 absorbing agent.

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                                            B. CONTROL METHODS
                                                      23
 24695
 Fairs, G. Lowrie
 HIGH-EFFICIENCY FIBRE  FILTERS  FOR  THE  TREAT-
 MENT OF FINE MISTS. Trans. Inst. Chem. Engrs. (London),
 vol. 36:476-485, 1958. 3 refs.
 The treatment of contact process  sulfuric acid plant tail gases
 to remove completely a sulfuric acid mist with particles of less
 than two micron was studied. If a filter of fine glass-wool is
 treated with a silicone to provide a water repellent surface, the
 acidity of the gases leaving the filter is reduced to 0.2% of the
 inlet acidity as  compared with 2.5% for untreated wool under
 similar operating conditions. This  twelve-fold improvement of
 scrubbing efficiency is important, since the gases scrubbed
 with the silicone-treated  fiber were invisible when vented to
 the atmosphere, while a visible plume persisted after scrubbing
 with the untreated fiber. A scrubbing efficiency of  99.6% was
 obtained with a garnetted Terylene polyester fiber, which is in
 itself  water repellent. Comparative performance data for the
 two filters are summarized. (Author abstract modified)

 24833
 York, Otto H. and E. W. Poppele
 TWO-STAGE MIST ELIMINATORS  FOR SULFURIC  ACID
 PLANTS. Chem. Eng. Progr.,  66(ll):67-72, Nov. 1970. 5 refs.
 Sulfuric acid plants, and plants producing oleum in  addition to
 sulfuric acid, are a major  source of concern to air pollution
 authorities because of the dense and highly corrosive acid mist
 discharged  with the absorption tower tail gas. Modern air pol-
 lution codes require that mist emissions from existing plants
 be  reduced  to  below 2 mg/std cu ft. Compliance  with these
 regulations is achieved at minimum cost by means of a two-
 stage  scrubber,  one stage designed  for the removal of the
 coarse fraction  of the mist and the other for removal of very
 fine mist particles.  Fluorocarbon fibers are used for  the con-
 tact stages as they combine complete corrosion resistance with
 high separation  efficiency at moderate pressure drop. Efficien-
 cy  of the scrubbers, unlike that of two-stage wire  mesh mist
 eliminators,  is  essentially 100% for particles down to  about
 one micron. Reduction of particles down to 0.3 micron is  also
 substantial.

 25133
 Donovan, J. R. and P. J. Stuber
 AIR POLLUTION SLASHED AT SULFURIC-ACID  PLANT.
 Chem. Eng., 77(25): 47-49, Nov. 30, 1970.
 Among processss for controlling emissions from  sulfuric acid
 production, attention is now being given to interabsorption, or
 double-catalysis. This system markedly lowers sulfur dioxide
 emissions  and gives higher conversion to acid  at generally
 modest  cost  penalties. While in a conventional contact-acid
 plant, SO2  is converted into  sulfur trioxide in one  operation,
 interabsorption instead  interrupts the reaction to remove some
 of the SO2  product. This  has a favorable  effect on both the
 kinetics  and  the equilibriu  of further  conversion. Equipment
required for an  interabsorption plant is similar to that of con-
 ventional facilities with the  addition of heat exchangers and an
interpass absorption tower.  Conversion  of 99.5%  can  be
guaranteed by the process as  compared to  98% for a conven-
tional  plant.  Capital and operating  costs, together with indirect
charges, are itemized  for  the first  facility in the  Western
Hemisphere  to use this  German-based process
25275
Nilsson, Folke and Bengt Rudling
AIR POLLUTION CONTROL AT THE BOLIDEN COPPER
AND LEAD SMELTING PLANT, ROENNSKAERSVERKEN,
SWEDEN.  Preprint, International Union  of  Air Pollution
Prevention Associations, 36p., 1970. (Presented  at the Interna-
tional Clean Air Congress, 2nd, Washington, D. C., Dec. 6-11,
1970, Paper SU-24D.)
Factors considered  when the Boliden Company's copper and
lead smelter was erected in Sweden in 1928-1930 are reviewed.
Built for smelting copper-arsenopyrite ore from  the Boliden
mine, the smelter was placed on a peninsula at the Bothnian
Gulf. To utilize excess sulfur in the ore as pyrite  and thereby
reduce the  sulfur  dioxide emission by about 50%,  the ore was
concentrated. After World War n a sulfuric acid plant took
care of the roaster gases  and ten years later the production
was increased three-fold by further SO2-utilization.  Hereafter
no effect can be seen on forest, crop, or garden. The concen-
tration of SO2 in ambient air around the the  smelter is  far
beneath the official  limit. The production of liquid SO2 for the
paper and  pulp industry will now make it possible to  utilize
over 90% of the SO2. The SO2-recovery is made by absorp-
tion in water. This process is economical when  a good supply
of cold water for cooling and inexpensive surplus steam is
available.  Along  with diversified and increased  production,
dust cleaning has been extended and modernized. The results
of these activities have been followed up by medical  studies of
the population. (Author abstract modified)

25370
Quitter, Volker
ELECTROSTATIC SEPARATION OF SO3 MISTS. Staub (En-
glish translation from German of: Staub,  Reinhaltung  Luft),
30(4):8-10, April 1970. 2 refs.
Electrostatic  precipitators  with special electrodes have been
used successfully  for  precipitating  sulfur trioxide  mists.
Production of sulfuric acid and oleum on an anhydrite base en-
tails the generation of waste gases with high sulfur dioxide and
SO3 contents which cause heavy damage  to agriculture  and
forestry.  Tail gas precipitators were  manufactured and  in-
vestigated under a variety of operational conditions.  Lead and
'korobon' plates were used as collecting electrodes,  while the
discharge electrodes consisted of barbed lead wire. SO2  and
S03 contents, temperature, and gas humidity were  measured
upstream and downstream of the precipitator. While  rising
SO3 content causes the current consumption to  fall,  collection
efficiency on the other hand will rise. The flashover limit is as-
sociated with the gas velocity and with the  composition  of the
tail gas.

25468
Glowiak, Bohdan and Adam Gostomczyk
SULFUR DIOXIDE SORPTION ON ANION EXCHANGERS.
Preprint,  International Union of Air Pollution Prevention As-
sociations,  19p., 1970. 10 refs. (Presented at the International
Clean Air Congress, 2nd, Washington, D. C., Dec. 6-11, 1970,
Paper EN-23E.)
The  experiment of using anion-renewable exchangers in sulfur
dioxid sorption  from gases was conducted in three stages.  An
artificially  created  mixture  of  sulfur dioxide and air  was
passed through  a column 50 mm in diameter in  the first stage.
The  column was filled with an anion layer 300 mm high. Next,
a laboratory device was use for obtaining SO2 from the  ex-
haust gases which were  emitted by a boiler-house. The gases
had  to be  dedusted and cooled before  passing  through  the

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 24
SULFURIC ACID MANUFACTURING
 column with anion. At the third stage, a pilot apparatus was
 installed in a sulfuric acid works, and the characteristic fea-
 tures of an installation working at this stage are described. The
 method which was utilized consisted  of  forcing gases with
 countercurrents through a  layer  of anion exchanger  resin
 which was sprayed with hydroxide solution. This method can
 be used for purification of gases  which have a temperature
 lower than 60 C and which do not contain dust. Efficiency in-
 creases slightly, simultaneous with the increasing  concentra-
 tion of spraying solution and with that of  SO2 in the purified
 gas. (Author abstract modified)

 25491
 Franz, Milan and Rostislav Klimecek
 PROCESSING OF SULFUR DIOXIDE  FROM COMBUSTION
 GASES. (Zpusob zpracovani kyslicniku siriciteho  ze  spalin).
 Text in Czech. (Czechoslovak Republic) Czech.  Pat. 110,995.
 3p., Dec. 15, 1963. (Appl. July 22, 1961, 1 claim).
 Sulfur dioxide from combustion gases  (from the manufacture
 of contact gas in the production of sulfuric acid) is absorbed
 by a solution of sodium hydroxide with the formation of sodi-
 um hydrogen sulfite. A surplus of sulfuric acid is then added
 to the absorption solution to obtain a pH  of approximately 1,
 yielding concentrated SO2 which escapes  and sodium sulfate
 which remains in solution. The sodium hydroxide needed for
 the absorption and the sulfuric acid needed for the decomposi-
 tion are recovered from the sodium sulfate solution  electrolyti-
 cally. Electrolysis generates oxygen in a quantity equivalent to
 the quantity of the sodium hydroxide recovered and thus also
 equal  to the quantity of absorbed SO2; the oxygen oxidizes
 SO2 to SO3. Sulfur trioxide from the combustion gases causes
 a  disequilibrium between sodium and sulfate ions in the solu-
 tion with a resulting accumulation of free sulfuric acid. This
 excess must be neutralized before  electrolysis and part of the
 solution of sodium sulfate equivalent to the SO3 content hi the
 combustion gas is  removed and the sulfate is recovered by
 crystallization. The method works at normal temperatures.

 25643
 Sykes, W. and F. Broomhead
 PROBLEMS    OF    ELECTRICAL    PRECIPITATION
 REVIEWED. Gas  World,  134(3494):98-104, Aug. 4, 1951. 5
 refs.
 Aspects of the design, construction, and operation of the elec-
 trical precipitator are discussed. The great advantage of this
 device is its ability to remove with high efficiency dust of par-
 ticle size much smaller than that removable by mechanical or
 cyclone  separators. Back  pressure,  and power   needs to
 produce the  corona discharge,  a very small; however initial
 costs are much higher. Problems considered at length include
 removal efficiency and its  relation to time contact of the gases
 in the field, design of the precipitation  chamber, insulator
 breakdown, gas distribution across the precipitator, removal of
 deposits from  electrodes,  and  electrical  equipment require-
 ments. Five  essential design factors are given:  correct time
 contact, good gas distribution throughout the fields,  design and
 arrangement  of the electrodes, maintenance of clean  elec-
 trodes, and maintenance of correct voltage. Examples of  the
 following typical application  are described and  the principal
 design features are indicated in each case to point up the great
 variety of  constructions required by  specific  and differing
 operating conditions: detailing of producer gas from coal and
 coke, chamber and contact process sulfuric acid manufacture,
 aluminum and cement production,  boiler flyash precipitation,
gypsum dust removal,  sodium  sulfate  recovery  in the Kraft
pulp industry, cleaning of blast furnace gas, air  conditioning,
and spray painting.
                         25717
                         Brink, Joseph A., Jr.
                         LIQUID  MIST  COLLECTION.  (Monsanto  Enviro-Chem
                         Systems, Inc., Chicago, LI.) U. S. Pat. 3,540,190. 7p., Nov. 17,
                         1970. 5 refs. (Appl. May 16, 1963, 5 claims).
                         A finely divided mist is separated and collected from a gas in
                         which the mist is disposed by passing the gas through a bed of
                         inorganic fibers (preferably glass fibers), composed almost en-
                         tirely from fibers having diameters within the range of about 5
                         to 30 micron and  compressed  to  a density of about  5-20
                         pounds  per cubic foot.  The mist is collected upon the surfaces
                         of the fibers, then drained from  the fiber bed by gravity flow
                         in a continuous liquid phase. The apparatus is  particularly use-
                         ful with respect to the removal and recovery of acid mists,
                         such as  sulfuric or phosphoric acids.

                         25742
                         Nakazono, T.
                         REMOVAL OF SO2 GAS. (Aryusan gasu kaishu hoho). Text in
                         Japanese.  (Koga Mine Industrial Co.  (Japan)) Japan.  Pat.
                         172,814. 6p.,  May 31,  1946.  (Appl. Oct. 28,  1940, claims not
                         given).
                         Sodium formate and/or calcium formate were used as the ab-
                         sorbents for the removal of sulfur dioxide gas of low concen-
                         tration under low temperature. The amount of SO2 gas ab-
                         sorbed  was remarkably increased with  an increase in the
                         amount  of absorbents.  With an increased amount of SO2 gas,
                         using the same concentration of  formate, the  amount  of  S02
                         absorbed increased until SO2 concentration reached 4%; it in-
                         creased  the least amount thereafter. The SO2  gas obtained by
                         heating  (55 to 100 degree) the formate solution which had ab-
                         sorbed SO2 gas was  utilized for producing sulfuric acid in in-
                         dustry. The formic acid, produced by the sulfuric acid which
                         was   an intermediate  product  during  this  procedure  was
                         neutralized with alkaline salt(s) to regenerate the  sodium or
                         calcium formate.  This  method is economical and can  be  util-
                         ized for the long-term removal of SO2 gas.

                         25768
                         Skrivanek, Jaroslav and Vladimir Cada
                         ABSORPTION OF SULFUR DIOXIDE IN A VENTURI TUBE.
                         (Absorpce kyslicniku siriciteho ve Venturiho trubici). Text in
                         Czech. Chem. Prumysl  (Prague), 7(32):340-343, 1957. 6 refs.
                         Gas containing 0.2%  SO2 emanating from the manufacture of
                         H2SO4 was absorbed in a venturi tube by a soda ash solution
                         dispersed by the gas stream in  the  constricted  neck of the
                         tube. The degree of absorption and loss of pressure were stu-
                         died  with the view of  testing the industrial feasibility of this
                         method  of  recovery  of sulfur. The venturi tube  can be used
                         only  where the pipeline gas pressure exceeds 50 cm H2O and
                         for comparatively low  concentrations of  gas to be absorbed.
                         The theoretical  relationship between gas absorption, gas flow
                         volume and velocity was analyzed, an equation for the depen-
                         dence of the absorption constant on  gas flow volume, on
                         liquid flow volume and on the intitial soda ash concentration
                         derived. The experimental  arrangement  and  the method of
                         determining the residual concentration of S02 in the gas fol-
                         lowing absorption is described.  The absorption  constant in-
                         creases  with increasing gas flow velocity  and  decreases with
                         increasing absorption liquid volume. The absorption constant
                         rise with rising gas flow velocity is greater than linear.  The ef-
                         fectiveness of the venturi tube increases with increasing gas
                         flow velocity, even though the contact between the phases is
                         shortened, because of  the positive effect of flow velocity on
                         the absorption constant.

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                                            B.  CONTROL METHODS
                                                       25
26095
Brink, J. A., Jr., W. F. Burggrabe, and J. A. Rauscher
FIBER  MIST ELIMINATORS  FOR HIGHER VELOCITIES.
Chem. Eng, Progr., 60(ll):68-73, Nov. 1964. 8 refs.
Fiber mist eliminators are now installed in various chemical
processes for air pollution control  and gas purification. The
design superficial velocity of the gas through the fibers  in
most  of the eliminators has been 5 to 30 ft/min.  Now, as a
result of extensive testing, eliminators are available with su-
perficial velocities of 30 to 90 ft/min,  or even higher. These
new  units are  smaller  and  less  expensive  than  previous
designs. Performance data is presented for high-velocity units
on sulfuric acid and phosphoric acid mist. At a large-scale sul-
furic acid plant, collection efficiencies as high as 96% are ob-
tained for  particles three microns and smaller, and pressure
drop is constant at 7.5 to 8.0 in. of water. The efficiency of the
unit does decrease on smal submicron particles when oleum is
produced.

26254
Perrine, Richard L. and Limin Hsueh
MISCELLANEOUS  INDUSTRIAL  EMISSIONS.  In:  Project
Clean Air.  California, Univ., Berkeley, Task Force 5, Vol.  1,
Section 14, 5p., Sept. 1, 1970. 3 refs.
Five broad categories of industrial polluters  are briefly con-
sidered,  as  weU as  their kinds  of  emissions and  control
problems. The inorganic chemical industry has problems with
hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid,
calcium oxide,  chlorine, soaps and detergents.  Steel produc-
tion is a  major industry,  but the open  hearth furnaces are
gradually  being  replaced  by  the  basic  oxygen furnace.
Although this also produces fumes, the new plants can be con-
structed with proper control equipment. Foundries may change
the work they do from day to day so that control problems are
at their worst,  but methods  to trap particles and  fumes are
available.  The handling of  large volumes of minerals normally
involves problems with dust, while the special biological ef-
fects of asbestos must be noted. Glass fibers can also be a
problem, as well as fluoride-containing ores. Copper lead, and
zinc mining and milling operations involve  dust  problems,
while sulfur oxides may be released during smelting. Hydrogen
sulfide, mercaptans, sulfide and polysulfides which have very
bad odors, and other  noxious gases are emitted during wood
pulp processing. Typical gaseous emissions from Kraft pulping
are presented  tabularly. Coffee  roasting plants,  slaughter-
houses, and pickel plants emit strong odors. An areas of con-
cern is new processes to break down waste and return it to a
state useful in natural processes without problems of storage.
A particularly important point which needs to be considered is
site location.

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26
                         C.  MEASUREMENT  METHODS
00040
ATMOSPHERIC  EMISSIONS  FROM  SULFURIC  ACID
MANUFACTURING PROCESSES. Public Health Service, Cin-
cinnati, Ohio, Division of Air pollution and Manufacturing
Chemists' Association,  Washington,  D.C.  (999-AP-13.) 1965.
127 pp.
Emissions to the atmosphere from the manufacture of sulfuric
acid were investigated jointly by the Manufacturing Chemists'
Association, Inc.  and the  U. S. Public Health Service; the
study was the first in a cooperative program for evaluation of
emissions from  selected chemical manufacturing processes.
The report describes the growth and potential of the sulfuric
acid industry, types of raw materials used, design of plants,
process variables, emissions from plants under normal operat-
ing conditions, and the methods and devices used to limit and
control emissions. The sampling and  analytical techniques by
which  emissions  were  assessed  are   presented in  detail.
(Authors' abstract)

00381
W. L. Crider
HYDROGEN  FLAME EMISSION SPECTROPHOTOMETRY
IN MONITORING  AD* FOR  SO2  AND  SULFURIC  ACID
AEROSOL. Anal. Chem. 37, 1770-3, Dec. 1965.
The principle of hydrogen  flame emission  spectrophotometry
is demonstrated to be of practical use in  monitoring the at-
mosphere of animal exposure chambers for SO2 in concentra-
tions from 0.1 ppm (v./v.) to 100 ppm  and for airborne droplets
of H2SO4 in  the concentration range from 0.17 to 5.2 mg per
cu meter. Some parameters influencing emission intensity are
explored. (Author)

00482
F. P. Scaringelli, R. E. Boone, and G.  A. Jutze
DYNAMIC  CALIBRATION  OF  AN  ACID   AEROSOL
ANALYZER.  J. Air  Pollution Control  Assoc. 16(6):310-313,
June 1966.
A method  is  described for  dynamic calibration  of an acid
aerosol analyzer based  on  a commercial modification of the
Thomas Autometer. This automated instrument removes acid
aerosol from an air stream by sonic impaction, and the sulfuric
acid collected is determined  conductometrically. An all-glass
aerosol generator based on the reaction of water vapor with
sulfur trioxide vapor released from fuming sulfuric acid  was
built for the calibration. Air  samples were withdrawn for in-
strument calibration before  and after  the concentration of the
acid aerosol was determined by titration. The apparent particle
size as determined by an Andersen sampler ranged from 2.0
microns to less  than 0.68 micron and exhibited a sharp peak
with mass median diameter at 1.3 microns in the distribution
curve. The size of the aerosol, within certain limits, could be
controlled by  humidity.  Data indicated a linear response with
an  aerosol collection efficiency of  80%  in  the important
respirable size range. (Author abstract)
01387
J.V. Kerrigan K. Snajberk
STUDIES ON SULFURIC ACID MIST DOWNWIND FROM A
SULFURIC ACID MANUFACTURING PLANT.  J. Air Pollu-
tion Control Assoc., 15(7):316-39, July 1965.
Air pollution downstream from a sulfuric acid manufacturing
plant is comprised of two aspects, the amount of acid mist fal-
lout and the concentratuon in the atmosphere. This investiga-
tion shows that it is desirable to determine each of these by an
independent method of collection. Pans of distilled water were
used to collect and determine the sulfuric acid  mist concentra-
tion in the atmosphere. The use of Stokes' Law to convert the
results obtained by one method to those obtained by the other
requires a knowledge of the particle size  of the sulfuric acid
mist droplets. Data presented show that the use of an average
particle size can yield a picture of pollution which is in error
by many orders of magnitude. The study shows that areas ad-
jacent to a plant may be  subjected to fallout of rather large
particle size when there  are not adequate methods for removal
from the emission or byproduct gases. (Author  abstract)

01819
R.E. Boone R.M. Brice
CONTINUOUS MEASUREMENT  OF ACID  AEROSOL  IN
THE ATMOSPHERE. Preprint.  (Presented at the 58th Annual
Meeting, Air Pollution Control Association, Toronto, Canada,
June 20-24, 19659)
Experience in operating  a combination acid aerosol and sulfur
dioxide automatic analyzer in ambient air at an urban site is
reported.  Data for a 1-month period showed an  average con-
centration of 9.2  micrograms/cu m of acid aerosol as sulfuric
acid and 550 micrograms/cu m  of sulfur dioxide. Limitations
of the instrumentation have been  determined and indicate ap-
preciable  variation in  acid  aerosol due  to losses from  in-
complete  impaction and from  measurement of nonacid elec-
trolytes as  acid  aerosol in the  conductivity cell. The overall
factors for converting instrument reading to actual acid aerosol
concentration averaged from 0.52 to 0.70 when determined by
3 methods. The appreciable variations in instrument response
to total acid aerosol in the air sampled, the range of variations
in impaction efficiencies for acid aerosol, and significant varia-
tions in instrument response to nonacid  electrolytes suggest
that much more study is necessary before  the practicability of
the present instrumentation for monitoring acid aerosol can be
determined. (Author abstract)

03035
M. Hayashi, S. Koshi, and H. Sakabe
DETERMINATION OF  MIST  SIZE  BY  METAL  COATED
GLASS SLIDE.  Bull. Nat.  Inst.  Indust.  Health (Kawasaki
Japan) 6, 35-42, 1961
A new method for the determination of mist size and numbers
of mist particles is described, which is useful  in air pollution
research as well  as in industrial  hygiene. A  glass  slide was
coated with a very thin  layer of metal film; iron was the best

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                                        C. MEASUREMENT METHODS
                                                      27
 of three metals tried. The slides were placed in an Owens type
 dust counter or a cascade impactor for the collection of mist
 particles. Both acid and alkaline mists were tested. As the cor-
 rosive particles hit the slide, metal was  dissolved  and the
 transparent holes which were formed could be detected under
 an  optical  microscope.  Methods for calculating true  particle
 size from the holes in the metal-coated slide are given.

 03852
 E. S. Kohen
 INDICATOR  TUBE FOR THE INSTANTANEOUS  DETER-
 MINATION OF THE SO2 CONTENT OF THE AIR. Indikator-
 rohrchen zur  Soforthestimmung des  So2 - Gehaltes  der Luft
 Chem. Tech. (Berlin) 18, (11) 688, Nov.  1966. Text in Ger.
 The tube was  developed to facilitate the rapid determination of
 SO2 required  for worker protection in the rapidly expanding
 sulfuric acid  and sulfide ore industry. The operation of the
 tube is based on  standard reaction tests for S2 and SO32-
 using sodium  nitroprusside in an alkaline medium. The adsor-
 bent is Fajan's powder. The preparation of the adsorbent and
 the complete indicator powder is described in detail. A calibra-
 tion table (ranging from a length of coloring of 2mm for an
 S02 concentration of 0.01 mg per liter to  60 mm for 0.64 mg
 per liter) is given. The sensitivity of the tube is about 0.01 mg
 per liter. Tubes tested in sulfuric acid  plants gave accurately
 reproducible results. H2S does not  affect the results unless
 present in very high concentrations.  The tubes are found to be
 superior to those of the firm 'drager' (adsorbent, silical gel; re-
 agent,  potassium iodide  and  starch)  with respect to cost, ease
 of manufacture, accuracy, and sensitivity. The tubes last about
 10 months.

 09033
 Scaringelli, F.  P. and K. A. Rehme
 DETERMINATION OF ATMOSPHERIC CONCENTRATIONS
 OF SULFURIC ACID AEROSOL. Preprint, Public Health Ser-
 vice, Cincinnati, Ohio, National Center for Air Pollution  Con-
 trol, ((10))p.,  1968.  32  refs. (Presented at the Division  of
 Water,  Air,  and  Waste  Chemistry,  American   Chemical
 Society, San Francisco, Calif., April 3, 1968.)
 A  new  sensitive,  relatively  specific  method has  been
 developed for sulfuric acid aerosol.  It is based on the collec-
 tion of the  aerosol by sonic impaction on a copper disc, or by
 filtration on glass fiber filters. The free  sulfuric acid or the
 prepared metal salt is thermally decomposed under a stream of
 nitrogen to sulfur trioxide. The sulfur trioxide is converted to
 sulfur dioxide  by a  catalytic bed of hot copper. The resulting
 sulfur dioxide  is determined spectrophotometrically or by titra-
 tion in a microcoulometer. Most salts of sulfuric acid do not
 interfere. Ammonium  sulfate responds quantitatively, but this
 fact is not considered objectionable. This salt, in all likelihood,
 results from the reaction of sulfuric acid and ammonia in the
 atmosphere. The method is reproducible and is suitable for the
 determination of sulfuric acid in the parts per billion range.

 09295
 N. N. Basargin, N. K. Oleinikova
DETERMINATION  OF SULFURIC ACID MIST  IN THE
GASES  FROM SULFURIC ACID CONTACT  PLANTS. Ind.
Lab. (USSRXEnglish  Transl.), 32(8): 1118-1119, Aug. 1966.  4
refs.
In order to meet the need for a method for the rapid and
precise determination of H2SO4 mist in gases containing acid
components and arsenic,  a  direct  volumetric method  was
developed for titrating sulfate ion  with a  barium salt in the
presence   of  a   new   indicator  for   barium,   namely
nitrochromazo.  Special   features   in   the  structure   of
nitrochromazo enable it to react with barium in an acid medi-
um.  The  titration  can be  carried  out  at pH 2.0,  which
completely eliminates the effect of arsenates. The basis of the
method was the direct titration of absorbed sulfuric acid, in a
50 percent aqueous acetone or aqueous alcohol medium, with
a   solution  of  barium   chloride  in  the  presence   of
nitrochromazo. The equivalent point was shown by a  sharp
change in the color of the indicator from violet to blue (com-
plex with barium). The gas was drawn through the system by a
vacuum pump. The sampling rate was 1 liter/min. The H2SO4
mist content  of the sample should be 20 to 40 mg.  The filter
with absorbed sulfuric acid was washed through  with distilled
water by means of a water pump. The wash water was col-
lected  in a 100 ml graduated  flask. The  sampling  tube was
washed out into the same flask, and the volume was made up
to the mark with water. An aliquot portion (10 to 20 ml) of this
solution was transferred to a 100 ml conical flask, the pH was
adjusted to 2.0 as judged by universal indicator paper, and the
liquid was  acidified with a few drops of N HCL.  An  equal
volume of acetone or alcohol was added, and the solution was
treated with 1 to 2 drops of 0.2 percent nitrochromazo solution
in water and titrated, with shaking, with 0.02 N BaC12 solution
until the color changed. The  strength of  the BaC12 solution
was  determined by  titration of 0.02 N H2SO4 solution under
the same conditions, in  the  presence  of nitrochromazo.  A
blank titration was carried out to check the purity of the water
and acetone or alcohol.  The titration with nitrochromazo as in-
dicator was checked with  pure acid solutions. The proposed
method was tested under laboratory conditions and at two sul-
furic acid plants. Results for the determination of H2SO4 mist
in production gases by the alkalimetric  and nitrochromazo
titration methods are compared; the former method gave high
results in most cases.

09369
Wilson, H. N. and G. M. Duff
INDUSTRIAL GAS ANALYSIS: A LITERATURE REVIEW.
Analyst, 92(1101):723-758, Dec. 1967. 712 refs.
Analytical methods are  reviewed for: permanent and inorganic
gases;  analysis of liquefied or pure gases;  fuel gases;  flue
gases; motor  exhaust gases; analysis of micro samples; and at-
mospheric pollutants. The years from 1958 to about mid-1966
were covered. In  no branch of analysis is the swing towards
physical  methods more marked than in gas analysis.  There
have  been no  important developments of  the  conventional
methods during the last ten years; the chief advances have
been the application of galvanic methods to 'trace' of certain
gases, and  gas chromatography. The rapid spread of the elec-
trogalvanic methods for  the  'on-stream'  determination of
traces is also most significant. The other most noticeable fea-
ture  is  the vast and increasing  attention  being  paid  to  at-
mospheric pollutants of all kinds,  particularly sulphur dioxide,
sulphuric acid and hydrocarbons.

09633
Green, W. D.
SENSITIZED FILMS FOR THE DETECTION AND ANALY-
SIS  OF CHEMICAL  AEROSOLS.  Preprint,  Meteorology
Research, Inc., Altadena, Calif., 12p., 1968. 4 refs. (Presented
at the 9th Conference on Methods in Air Pollution and  Indus-
trial Hygiene  Studies, Pasadena, Calif., Feb. 7-9, 1968.)
The chemical species to be detected in the aerosol undergoes a
specific reaction with the indicator in the film following impac-
tin and absorption of the particle. At the present time, films

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 28
SULFURIC ACID MANUFACTURING
for the detection of sulfate, halide,  iodine,  iodide, oxidants,
nonspecific  acids and  bases,  and sulfuric  acid  have been
developed. Semi quantitative analysis of the ion concentration
in single particles particles is possible by precalibration of the
films with droplets aerosolized from  solutions of known con-
centration. These films have been used on various air pollution
oriented programs to trace sulfates, halides, and acid aerosols
in the Los Angeles Basin and near  San Juan, Puerto Rico, and
to detect  halides and  acid  aerosols in automobile exhaust.
(Author's abstract, modified)

09983
Ubl, Z.
UNIFIED  METHODS  FOR THE ANALYSIS  OF  POLLU-
TANTS IN THE FREE ATMOS- PHERE. Acta Hygienica, No.
1, Suppl, 1966. 84p. 24 refs.
Methods for the analysis of pollutants in the air are presented
with precise and complete notes dealing with procedure, ap-
paratus, reagents, and possible problems. Procedures are given
for determining the following compounds in the air: SO2, CO,
NO2, NOx,  sulfuric acid  aerosols, C12,  H2S, Pb compounds,
CS2, phenol, As, F2, NH3,  soot,  Mn compounds, SiO2, and
formaldehyde. Also discussed  are methods  of  air sampling,
calibration methods, calculations, sensitivity and error in the
determinations interferences from  other compounds,  and the
principle involved in the method.

11089
Scaringelli, F. P. and K. A. Rehme
DETERMINATION OF  ATMOSPHERIC CONCENTRATIONS
OF    SULFURIC   ACH)    AEROSOL    BY    SPEC-
TROPHOTOMETRY,   COULOMETRY,    AND   FLAME
PHOTOMETRY. Preprint, Public Health Service, Cincinnati,
Ohio,  National  Air Pollution  Control  Administrstion, 27p.,
1968.  34  refs.  (Presented before the American Chemical
Society, Div. of Water, Air and Waste  Chemistry, San Fran-
cisco, Calif., April 3, 1968.)
A sensitive, relatively specific method for sulfuric acid aerosol
has been developed. The method is based on the collection of
the aerosol by sonic impaction on  a copper disc, or by filtra-
tion  on glass fiber  filters.  The  free  sulfuric acid or  the
prepared metal salt is thermally decomposed under a stream of
nitrogen to sulfur trioxide. The sulfur trioxide is converted to
sulfur dioxide by a catalytic bed of hot copper. The resulting
sulfur dioxide is determined spectrophotometrically or by titra-
tion  in a microcoulometer. Most salts of sulfuric acid do not
interfere. Ammonium sulfate responds quantitatively,  but this
fact  is not considered objectionable. This salt, in all likelihood,
results from the reaction of sulfuric acid and ammonia in the
atmosphere.  The method is reproducible  and is suitable for the
determination of sulfuric  acid  in the parts per billion range.
(Authors' abstract, modified)

11140
Cares, Janet Walkley
THE DETERMINATION OF OXIDES OF SULFUR BY X-RAY
EMISSION  SPECTROMETRY. Am.  Ind.  Hyg.  Assoc. J.,
29(4):386-389, July -Aug. 1968.
Determination  of sulfur dioxide, sulfur trioxide,  or  sulfuric
acid  mist becomes difficult in the presence of other acid gases
or where  collected samples  are highly  colored or turbid. A
method is  described by  which all oxides  of sulfur are oxidized
arid  precipitated  as  barium  sulfate.   The  barium  in  the
precipitate is determined by measuring the intensity of the L-
alpha emission produced by x-ray excitation. The method is
                        useful for about 0.05 to 10 micromoles of oxides of sulfur in
                        the aliquot analyzed. (Author's abstract)

                        12596
                        O'Keeffe, Andrew E.
                        Affi POLLUTION INSTRUMENTATION.  STATE OF  THE
                        ART. Preprint, National Air Pollution Control Administration,
                        Washington, D. C., Methods Development Section, 23p., 1968
                        (?).  (Presented  at the American Council of Independent
                        Laboratories, Inc., Annual Meeting, Washington, D.  C., Oct.
                        20, 1968.)
                        Brief descriptions of a number of new air pollution monitoring
                        instruments being developed are presented. A key feature of
                        these devices is  their ability to  sense and measure pollutants
                        without use of reagents in solution. A flame photometric sulfur
                        detector is being modified to read sulfur dioxide by gas chro-
                        matography.  Fuel cells  can  be  made for burning  carbon
                        monoxide,  methane,  SO2, or other compounds of  interest.
                        Semiconductors, such as zinc oxide change resistance when
                        exposed to certain compounds.  Microwave plasma detectors,
                        in conjunction with spectrophotometers, can analyze certain
                        gases.  A chemiluminescent ozone monitor can  measur ozone
                        due to a release of light energy in direct proportion to the par-
                        tial pressure of ozone.  The permeation tube primary standard
                        emits  a constant supply of  a desired gas, a  feature which
                        makes it desirable as a  standard. Variations of gas chromatog-
                        raphy  and mass spectrometry are discussed. A system for the
                        analysis of sulfur trioxide (sulfuric acid mist) is described. Not
                        all of these methods will necessarily be commercial successes,
                        but a number of  them will certainly prove to be of great value
                        in the detection of air pollutants.

                        14486
                        Uhi, K.
                        THE DETERMINATION OF ACIDIC GASES IN WORKING
                        ENVIRONMENTS BY ALKALI FILTER PAPER. (Alkali roshi
                        ho  ni yoru sagyo kankyo chu sansei gas no sokutei). Text in
                        Japanese. Nippon Eiseigaku Zasshi (Japan J. Hyg.), 24(1):49,
                        April 1969.
                        The alkali filter  paper  method for determining acid gases in
                        working environments  entails soaking  filter paper in a  30%
                        potassium carbonate  solution, drying the paper in air, and
                        putting it in a vinyl holder having an exposure area of 64 sq
                        cm. Absorbed gases  are extracted with distilled water and
                        determined qualitatively and quantitatively. The required expo-
                        sure time is determined by the type of acid being measured,
                        the production process, and the sensitivity of  the determina-
                        tion method.  Generally, 1  to 8 hrs are appropriate for acidic
                        gases like S02, HC1, and NO2, and 8 to 24 hrs for acid mists
                        of sulfuric, phosphoric, and chromic acids.  One hour is usually
                        required for  SO2  measurements by the para-rosaniline for-
                        maline method; the CL-Ba method requires 8 to 24 hrs. When
                        the relationship between the amount of SO2 adsorbed on the
                        filter paper and the average gas  concentration  in the  working
                        environment is plotted,  a curve is obtained. Thus, on a per day
                        basis, the coefficient of conversion depends on the amount ad-
                        sorbed. However, the  graph for an hour of exposure time is
                        linear, suggesting that shorter exposure times  would be con-
                        venient for the calculation.

                        14735
                        Steinke, Irmhild
                        CONTRD3UTION TO THE DETERMINATION  OF SO2  AND
                        SOS IN WASTE  GASES. (Beitrag  zur  potentiometrischen
                        Bestimmung von SO2 und SOS in Abgasen). Text in German
                        Z. Anal. Chem., 244(4):253-254, 1969. 3 refs.

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                                       C.  MEASUREMENT METHODS
                                                     29
 In  the  determination  of sulfur  trioxide  and sulfuric acid
 aerosols in the presence of sulfur dioxide, the latter substance
 is oxidized  to SO3 and  both  oxides are determined jointly.
 After additional  determination of the S02 content, the SO3
 content is obtained from the difference. In experiments to test
 this method, both oxides were absorbed in NaOH/H2O2 solu-
 tion. Woulf's absorbing flask was used for this purpose. Gas
 components which are not immediately absorbed will be ab-
 sorbed after shaking. In this alkaline solution, the SOS (com-
 posed of  SOS and the oxidized SO2)  is  present in form of
 sulfate ions, which are best determined by the method of Bau-
 disch, Beilstein,  and Neuenhausen to an accuracy of plus or
 minus 0.16 mg. The SO2 concentration was separately deter-
 mined by  absorption in Na2(HgC14) solution (West and Gaeke
 method). By this approach, the SO2 and SOS concentrations in
 waste gases from sulfuric acid plants can be determined to a
 minimum concentration of 1 g/cu m plus or minus 0.07 g/cu m.

 15745
 Dubois, L., R. S. Thomas, T. Teichman, and J. L. Monkman
 A GENERAL METHOD OF ANALYSIS FOR HIGH VOLUME
 AIR  SAMPLES.  I.  SULFATE  AND  SULFURIC ACID.
 Microchim. Acta, vol. 6:1268-1275, Nov. 1969. 11 refs.
 A method for analyzing high volume samples, particularly with
 respect  to sulfates  and  sulfuric acid,  was described which
 makes use of microdiffusion at 200 C to separate the volatile
 sulfate fraction from an aliquot portion of an air sample on a
 glass fiber. This  separation ensures  that only fixed sulfate is
 left in the aliquot disc after heating, and that the sulfuric acid,
 if originally  present, will be removed. At the same time, any
 sulfuric  acid evolved is trapped in a sodium hydroxide absor-
 bent, which can  be analyzed for fixed soluble sulfate using a
 method  specifically for  sulfates. The measurement of the
 separated  volatile  sulfate  may  then be  carried out  by
 microtitration or by  square  wave polarography. The polaro-
 graphic  method is more rapid and agrees with values found by
 microtitration; it is readily adapted to large scale analyses, and
 analytical  speed  can be  improved. The proposed method is
 free  from  inaccuracies   and   ambiquities  associated  with
 procedures  which  depend upon  pH measurement or  non-
 specific  acid-base titration.

 19384
 Taylor, H. D.
 THE CONDENSATION OF SULPHURIC ACID ON COOLED
 SURFACES  EXPOSED  TO  HOT  GASES  CONTAINING
 SULPHUR TRIOXIDE.  Trans.  Faraday Soc.,  vol. 47:1114-
 1120, 1951. 8 refs.
 Laboratory apparatus and techniques are  described for  sam-
 pling and analyzing the sulfuric acid condensing from a hot gas
 mixture  of known water vapor and sulfur trioxide contents.
 The essential feature of the technique is the vaporization of
 sulfuric  acid into an air stream of known composition and its
 condensation upon a  surface held at a known temperature in
 such a  manner that  the condensate could be sampled and
 analyzed. Over the range of gas composition studied (from 60
 to 600 ppm of SO3), the concentration of the condensate is not
affected by  the proportion of  sulfur  trioxide present. It is a
function only of the surface temperature and the water vapor
content of the gases and, independent of the latter,  there is a
peak in  the rate of condensation at a surface temperature ap-
proximately  45-50 C  below the dewpoint. The magnitude  of
this peak increases with increasing dewpoint. (Author abstract
modified)
20595
Wyszynska, Halina, Konrad Kosinksi, Stefan Maziarka, Z.
Misiakiewicz, and Artur Strusinsky
METHODS FOR THE SANITARY INVESTIGATION OF AT-
MOSPHERIC  AIR  DEVELOPED BY  THE SECTION  OF
SANITATION LABORATORIES FOR THE PROTECTION OF
ATMOSPHERIC Ant. (Metody sam'tarnego badania powietrza
atmosferycznego  opracowanie  zespolu  Pracowni  Sanitamej
Ochrony   Powietrza   Atmosferycznego).    Wydawnictwa
Metodyczne Panstwowego  Zakladu  Higieny  (Methodologic
Study Govt. Dept. Hyg.), no. 4(26); issue no. 10, 149p., 1968.
78 refs.  Translated from Polish. Franklin Inst. Research Labs.,
Philadelphia, Pa., Science Info. Services, Oct. 14, 1969.
Methods are presented for determing atmospheric pollutants,
with the exception of carbon monoxide and gasoline, the con-
centrations of  which are defined by Polish law.  In addition,
methods are given for the determination of pollutants present
in the atmosphere in quantities sufficient to  create sanitation
problems or to cause plant damage and corrosion to buildings.
Some of the methods have been checked and  tested extensive-
ly in the laboratory and in the field. Others have not yet been
widely tested but are included  for their potential usefulness in
laboratory studies. The methods include the  measurement  of
dust collected by  the deposition method with respect to tars,
sulfates, free silica, heavy metals, calcium, and fluorine.  The
other methods are the aspiration and contact  methods for sul-
fur  dioxide;  the  method  employing thorium  nitrate  and
eriochromecyanin R for sulfur trioxide-sulfuric acid; the para-
aminodimethylaniline method for hydrogen sulfide; methylene
blue and diethylamine and copper methods  for carbon disul-
fide; the Saltzman method for nitrogen oxides; titration with
thorium   nitrate   and   colorimetric   determination  with
eriochromecyanin and zirconium oxychloride  for fluorine;  o-
tolidine  for chlorine; titration for hydrogen chloride; buffered
potassium  iodide and  the  Heigal method  for  ozone;  the
Schryver method for formaldehyde; para-aminodimethylaniline
and diazo-p-nitroaniline for phenol; nitration  for benzene and
chlorobenzene; and the indophenol method for aniline.

21056
Takahashi, Akira
ELECTROCONDUCTrvTry ANALYZER. (Taikichu no SO2
sokuteiho. 3.  Yoeki dodenritsuho). Text in  Japanese. Netsu
Kami (Tokyo) (Heat Eng.), 22(2):60-64, Feb. 28, 1970. 1 ref.
An electroconductivity analyzer was adopted to monitor sulfur
oxides in a specified area in conformity with the requirements
of the air pollution prevention  law. The conductivity of an ab-
sorbent  reaction solution is increased by sulfuric acid, which is
formed by a reaction of hydrogen peroxide with the sample at-
mosphere. The density of the sulfur oxides is  measured as an
increase in conductivity. Measurement can be intermittent, au-
tomatic, or continuous. In one  procedure the reagent used is a
solution of 0.006% H202 and .00005  N sulfuric acid. The re-
agent will last for 20 days if 20 liters  are used. A recorder can
simultaneously measure  the oxidized sulfur substance  and
floating  gas. Sampling should be made to extract a representa-
tive sample of atmosphere at a specified district.

21415
Larrat, P. and J. Louise
CONTINUOUS DETERMINATION OF  TRACE AMOUNTS
OF SO2 IN THE ATMOSPHERE AND IN OTHER GAS MIX-
TURES.  (Dosage continu de traces de SO2 dans 1'atmosphere
et autres  melanges gazeux).  Text in French.  Chim. Anal.
(Paris), 52(4):397-399, April 1970. 3 refs.

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 30
SULFURIC ACID MANUFACTURING
A method is proposed for making a wide range of sulfur diox-
ide content determinations: from concentrations on the  order
of 10 to the minus 6th power to those on the order of 10 to the
minus 2 power. It offers the advantage that it does not require
reference gas mixtures but only titred sulfuric acid solutions.
The sulfur dioxide is first oxidized with hydrogen peroxide,
after which  the resulting sulfuric acid is determined by the
conductimetric method. The method was tested with a gas rate
of flow of 20 1/hr using 100 cu cm/hr of the liquid reagent. Ab-
sorption  of SO2 was  complete, and the relative accuracy of
measurement was plus or minus 3 %.

22645
Barton, Sydney C. and Henry G. McAdie
PREPARATION OF  GLASS FIBER  FILTERS FOR  SUL-
FURIC   ACID   AEROSOL  COLLECTION.  Environ.   Sci.
Technol., 4(9):769-770, Sept. 1970. 5 refs.
When using  glass fiber filters for sampling air containing
microgram quantities of sulfuric acid, close attention must be
given to  blank effects since the residual  alkali content of the
filters can result in H2SO4 losses of 0.4 to 7.8 micrograms per
sq cm of filter. In a new procedure,  the sulfur  contaminants
responsible for the  irreversible absorption of H2SO4 on the
filter are deactivated by soaking the filter in  20% H2SO4 for
two to  three days,  then  rinsing  it in distilled  water, 80%
isopropanal, and acetone. No  H2SO4 losses have been ob-
served in filters treated in this manner.

23771
Patton, W. F. and J. A. Brink, Jr.
NEW EQUIPMENT  AND TECHNIQUES  FOR  SAMPLING
CHEMICAL PROCESS  GASES. J. Air Pollution Control As-
soc., 13(4):162-166,  April 1963.  7 refs (Presented at the Air
Pollution Control Association, 55th Annual Meeting, Chicago,
May 20-24, 1962.)
When the  need  for  improved  sampling  equipment  and
techniques was recognized at Monsanto a number of  years
ago, a cascade  impactor suitable for  adiabatic measurements
on process gases was developed. Simpler equipment, suitable
for routine control of air pollution, can determine accurately
the weight or chemical  composition of the particles in  a gas
stream, as well as separately determine the loading of particles
greater than three micron in diameter from particles  smaller
than this. The dust or mist sampling device is contained in a
small case with a carrying handle and removable sides similar
to an Orsat analyzer. Gases first enter the  cyclone where the
larger particles  are collected, while the  smaller particles are
carried over and collected by the filter. Sampling preparations
are discussed for large particles, fine  particles, and isokinetic
sampling. The procedures for sampling are outlined, as well as
an  example  for sulfuric acid mist. Calculations of loadings
from sampling data are also indicated. Eight  sets of the sam-
pling equipment have been utilized for sulfuric, phosphoric,
and  nitric acid  mists, mercury mist,  various phosphate salt
dust, ammonium chloride fume,  ammonium nitrate fume, and
several organic mists.

24970
Heilingoetter, R.
ANALYTICAL METHODS USED TO DETERMINE DAMAGE
BY ACIDS IN THE  ATMOSPHERE.  (Die chemische Unter-
suchungsmethoden des Luftsaeureschaedenexperten). Text in
German.  Chemiker-Zeitung, 51(45):429-433, June 8, 1927.
The  three methods  available for the assessment of damage
caused by atmospheric acids are the so called leaf and needle
                         ash analysis which directly measures damage caused to plants,
                         atmospheric  acid analysis by which the harmful content of
                         acids can be measured on the spot and the qualitative deter-
                         mination of small quantities  of acid in the atmosphere. The
                         first method is based on the accumulation  of acid in the ex-
                         posed plants. In the ash of such exposed plant material (nee-
                         dles  of  conifers for example) water  soluble sulfuric acid,
                         chlorine, fluorine, and nitrogen are determined and the excess
                         over  normal levels  is calculated. The second method, analyz-
                         ing air acidity directly, uses a series of absorption bottles filled
                         with different absorbent liquids designed to retain carbon diox-
                         ide, sulfur dioxide,  sulfur trioxide, nitrogen oxides, ammonia,
                         chlorides and hydrochloric acid which  are  then measured by
                         appropriate analytical methods and the respective acidity is
                         calculated. Toxicity limits are for SO2  3 mg/cu m, for N204
                         50 mg/cu m, for NH3 30 mg/cu m, for  HC1 110 mg/cu m, for
                         C12 64 mg/cu m and for  HF 0.00033 vol %. The  qualitative
                         method uses cotton cloth  dipped in a barium hydroxide solu-
                         tion and in lime water to determine the presence in the at-
                         mosphere of SO2 and of F respectively.

                         25445
                         Barton, S. C. and H. G. McAdie
                         A  SPECIFIC METHOD  FOR  THE  AUTOMATIC DETER-
                         MINATION OF AMBIENT H2SO4 AEROSOL. Preprint, Inter-
                         national Union of Air Pollution Prevention Associations, 19p.,
                         1970. 25 refs. (Presented at the International Clean Air Con-
                         gress, 2nd, Washington, D. C., Dec. 6-11 1970, Paper CP-7D.)
                         Although the importance of sulfuric acid (H2SO4) aerosol as a
                         toxic air pollutant is well established,  the aerosol has received
                         limited attention due to the lack of a satisfactory method for
                         its determination. An instrument that employs new and im-
                         proved versions  of the established techniques of collection by
                         filtration and colorimetric analysis  provides a  convenient
                         method for the  automatic determination of ambient H2SO4
                         aerosols  under  field conditions.  The  aerosol  is  collected,
                         together with other particulates, on  a Nuclepore polycarbonate
                         membrane  filter, then selectively  eluted with 1-propanol  for
                         colorimetric analysis by the barium chloranilate method. Air is
                         sampled at the rate  of 20 1 reciprocal min, and one-hour sam-
                         pling  intervals provide a full-scale sensitivity of 1 ppb, with a
                         detection limit of approximately .05  ppb. The availability of
                         this convenient and specific  method  should make  it feasible
                         for air quality authorities to undertake  meaningful surveys to
                         establish H2S04 levels which at present are unknown or in
                         serious doubt because of the limitations  of existing methods.

                         25851
                         Nash, T.
                         LOW-VELOCITY GAS-LIQUTO EMPEVGER FOR THE CON-
                         TINUOUS  ESTIMATION  OF SULPHUR   DIOXIDE  AND
                         OTHER  ATMOSPHERIC  POLLUTANTS.  J.  Sci. Instr.  vol.
                         38:480-483, Dec.  1961. 3 refs.
                         An impinger is described, based on the observation that a low-
                         velocity jet of air containing sulfur dioxide can transfer it very
                         efficiently to the surface of dilute hydrogen  peroxide, then by
                         rapid micro-circulation to the underlying solution. Air is drawn
                         into the cell compartment through a filter and glass jet, blow-
                         ing vertically down onto 0.1  volume peroxide in the  cell in
                         which SO2 is scrubbed from the air and converted to sulfuric
                         acid.  The electrical  conductivity of the  solution in  the cell is
                         measured through electrodes connected  to a simple oscillator,
                         amplifier, and recorder. The vapor reaction, electrical circuit^
                         stock  solution,  jet  characteristics,  and time  constant  are
                         discussed.  Calibration and performance are  also  described.
                         The instrument records SO2 in the range 0.01 to 10 ppm where

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                                       C. MEASUREMENT METHODS                                    31

rapid changes in concentration can be expected but the accura-     and no peroxide, it is possible to record carbon dioxide con-
ey required is not more than 1 in 20. Its advantage is that gas     centration  in  the range normally encountered in air. One
absorption and measurement of  conductivity  are done in the     modification of the instrument  measures  light  absorption  in-
same  small cell, with the  consequent  gain in simplicity  and     stead  of conductivity,  permitting the use of colonmetnc  re-
speed of response. By using 0.1 mM alkali in the reservoir,     agents.

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32
                    D.  AIR  QUALITY  MEASUREMENTS
05152
J. V. Kerrigan, and K. Snajberk
STUDIES ON SULFUR OXIDE POLLUTANTS IN THE AT-
MOSPHERE. California Univ., Berkeley, Sanitary Engineering
Research Lab. May 10, 1960. 82 pp.
The location of the laboratory in an area zoned for heavy in-
dustry and having a  local air pollution problem, together with
the availability of an industrial sampling chamber as a source
of sulfur oxide gases,  made  experimental  work particularly
feasible. The investigation was therefore designed to deter-
mine: (1) the comparative reliability of  various  instruments
used to sample and detect sulfur oxide particles and gases; (2)
the accuracy of various chemical  methods of sulfate analysis
at low sulfate ion concentrations; and (3)  the concentration of
certain sulfur  oxide gases  in the  local atmosphere at  the
Richmond Field Station. Pans of distilled water were set up in
the path  of prevailing  winds in such fashion that the winds
would pass over an adjacent sulfuric acid manufacturing plant
before entering the Field Station area. The pans were used to
measure the fallout  of  sulfuric acid mist droplets, while an
electro-static precipitator set adjacent to one of the pans mea-
sured the concentration of sulfuric  acid mist in the air. The
validity of the electro-static precipitator results was confirmed
by comparison with a  Greenburg-Smith impinger and with a
sintered glass filter  by  sampling a gas  chamber containing a
mixture of sulfur dioxide and sulfuric acid mist under steady-
state conditions. To approximate the concentrations of sulfuric
acid  mist under field conditions,  samples fed to  the instru-
ments were diluted 10 to 50-fold with air. Both a Kruger  au-
tometer  and a Thomas autometer were used to collect and
analyze  for sulfur  dioxide.  The  turbidimetric,  the  Fritz
titrimetric,  the  pH  titration,  and  the acidimetric titration
methods of chemical analysis for sulfate were compared in the
course of the investigation.
11492
Polyak, V. E.
ATMOSPHERIC POLLUTION BY NITROGEN  OXIDES IN
THE  MANUFACTURE OF  SULFURIC  ACID  BY  THE
TOWER  PROCESS.  ((Zagryaznenie atmosfernogo vozdukha
okislami  azota pri bashennom proizvodstve sernoi kisloty.))
Hyg. Sanit. (English  translation of: Gigiena i bSsanit), 33(4-
6):266-267, April-June 1968. CFSTL TT 68-50449/2
An investigation of atmospheric pollution by nitrogen oxides
(tail gases from the plant for the manufacture of  sulfuric acid
by the tower process) at various distances from the pollution
source was  made. The gases are discharged into the  at-
mosphere by a chimney 40 m tall. The daily discharge into the
atmosphere amounts to 4 tons of nitrogen oxides (expressed as
nitric acid), with a gaseous volume of 817 cu m. There are no
other discharges of nitrogen oxides on the factory premises or
elsewhere in the district. Air was sampled at a level of 1-1.5 m
from the  ground, in the direct vicinity of the chimney, and at
distances of 500, 1,000,  3,000 and 6,000 m, the total number of
samples being 413. Measurements were made of the tempera-
ture, relative humidity  and velocity  of the air  and of the
barometric pressure, wind direction, cloudiness, and the color
and movement of the visible  'tail'  of the gas  discharge.
Nitrogen  oxides were  detected and determined at the laborato-
ry in most samples (79-89.3%). In a considerable number of
samples the concentration of nitrogen  oxides exceeded the
maximum permissible concentration, including  some samples
taken  at  large distances from  the discharge site (3,000 and
6,000 m). All minimum  concentrations were either equal to or
lower than the  maximum permissible concentration, but the
maximum concentrations exceeded this level. The mean con-
centrations of nitrogen oxides likewise exceeded the maximum
permissible concentration, being 2.45 mg/cu m at  the distance
of 6,000 m, i.e., eight times the maximum permissible concen-
tration.

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                                                                                                              33
                     E.  ATMOSPHERIC  INTERACTION
10751
Hoegstroem, Ulf
A  STATISTICAL APPROACH TO THE AIR POLLUTION
PROBLEM  OF  CHIMNEY  EMISSION. Atmos. Environ
2(3):251-271, May 1968.
A method is described that not only gives one single concen-
tration value but the expected concentration  frequency dis-
tribution  at an arbitrary point in the vicinity of the  emitting
chimney.  The  concentration  frequency distribution obtained
comprises the  full  range  of meteorological conditions  at a
given  place.  In making the principal mathematical formulation
of  the method no assumptions  whatsoever are needed about
the mechanism of dispersion. In the practical application on
the other hand, full use is made of the detailed knowledge of
the dispersion process. First a 'basic case' is treated, the chief
characteristics of which are: isolated  stack, situated on a flat
surface of uniform roughness; sampling  time about an hour.
The following  information is found necessary for solving a
concrete problem of this kind. (1) plant data, viz. rate  of emis-
sion, gas volume and temperature, chimney  height and exit
diameter; (2) geographical site data, viz. roughness length; (3)
meteorological  data,  viz.  wind  direction frequencies  and
statistics  of 'dispersion categories'  (stability and wind speed).
Applicable formulae are discussed  and also how statistics of
'dispersion  categories' can  be  obtained by  evaluating  data
from  radiosonde stations.  Certain  deviations  from the basic
case are also treated in some detail; limited mixing height, the
effect of  large  heat content on the  dispersion parameters, the
effects of buildings and topography, ground level release and
sampling  times other  than an hour. A thorough test of the
described method is presented. Nine months statistics of 2-hr
SO2 concentration (2602 values) measured at a point situated
750 m from a sulphuric acid plant are compared with theoreti-
cally obtained  statistics.  The results strongly  supports the
method presented.

21791
Katz, Morris
PHOTOCHEMICAL REACTIONS OF ATMOSPHERIC POL-
LUTANTS.  Can. J. Chem. Eng., vol. 48:3-11, Feb.  1970.  44
refs. (Presented at the Canadian Chemical  Engineering  Con-
ference, 19th Edmonton, Alberta, Oct. 19-22, 1969.)
Photochemical   reactions  of  atmospheric pollutants   are
described. The  most important primary photochemical process
is the dissociation of  nitrogen dioxide into  nitric and atomic
oxygen. Activation energy for most atmospheric reactions may
be supplied by absorption of ultraviolet and visible light by
molecules and atoms that act as absorbers.  The  formation of
free radicals from the photodissociation  of aldehydes and
other compounds which absorb  solar radiation represents an
important step in the series  of reactions  that lead to the
production of eye irritation, plant damage, and photochemical
smog. The meteorological and chemical circumstances which
lead to photochemical smog are explained. Quantum yields
from the  photooxidation of sulfur dioxide are discussed, and
an experimental method is described. The effect of humidity,
nitrogen dioxide, light  intensity, and unsaturated hydrocarbons
are  included. The  roles of sulfuric  acid aerosols,  singlet ox-
ygen, and ozone are analyzed.

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34
              F.  BASIC  SCIENCE  AND  TECHNOLOGY
00530
W. O. Negherbon
SULFUR DIOXIDE,  SULFUR TRIOXIDE, SULFURIC ACID
AND FLY ASH: THEIR NATURE AND THEIR ROLE IN AHt
POLLUTION. Hazleton Labs., Inc., Falls Church, Va. June
1966. 1218 pp.
This monograph discusses the following: (1) Historical  con-
siderations; (2) Guidelines for the study of  air pollution; (3)
Physical and chemical properties of SO2, SOS, and H2SO4; (4)
Meteorological considerations; (5) Anatomical and physiologi-
cal considerations; (6) Deposition and retention of aerosol par-
ticles  in  the respiratory  tract;  (7)  The effects of SO2 and
H2SO4 on plants; (8) The effects of  SO2,  SOS, and H2SO4
mist on man and animals; (9) Fly ash origin, nature, and possi-
ble  effects; and (10) Removal of pollutants  from flue gases.
The bibliography includes 2264 references.

04626
D. R. Coughanowr and F. E. Krause
THE REACTION OF S02 AND 02 EM AQUEOUS SOLUTIONS
OF  MNS04. Ind. Eng. Chem. Fundamentals  4, (1) 61-6, Feb.
1965.
An experimental investigation was made to determine  the rate
of reaction  of sulfur dioxide and oxygen in  aqueous  solution
containing manganous sulfate as a catalyst. The catalyst was
varied from 0 to 15 p.p.m. of MnSO4 in a batch method, and
from 100 to  10,000 p.p.m. in a flow method. The temperature
was 25 C. The reaction is zero order with respect to both sul-
fur  dioxide  and  oxygen. The  concentration  of manganous
sulfate has a large  effect on the rate of reaction; from  0 to 100
p.p.m. of manganous sulfate, the reaction rate constant, k, is
proportional to the square of the catalyst concentration, but
above 100 p.p.m., k increases less rapidly  up to about 500
p.p.m., after which k increases very slowly with catalyst con-
centration.  The reaction is  easily inhibited by very  small
amounts of contaminant.

10907T
Lunge, G. and E. Berl
NITROGEN OXIDES AND THE LEAD CHAMBER PROCESS.
H. BEHAVIOR OF A MIXTURE OF GASES, PRESUMABLY
NO  +  NO2, IN CONCENTRATED SULFURIC  ACID  AND
SODIUM  HYDROXIDE  1/5  N.  ((Untersuchungen  ueber
Stickstoffoxyde und ueber den Bleikammerprozess. II.  Verbal-
ten  eines Gasgemisches von der ungefaehren Zusammenset-
zung NO  +  NO2 gegen konz. Schwefelsaeure  und  1/5-n.
Natronlauge.)) Translated from  German. Z. Angew. Chem.
(Weinheim), 19(19):857-869, May 1906.
The behavior of a gas mixture containing NO and NO2 in sul-
furic acid and sodium hydroxide  was investigated with the
result that for analytical purposes sulfuric acid is the only ab-
sorption liquid for this gas mixture. Also  the behavior of
nitrogen oxide in the presence of oxygen and water was stu-
died together with the kinetics of nitrogen oxide oxidation with
oxygen or air. The kinetic curves indicated  that the reaction
2NO+O2=N2O4 takes place at a constant rate which indicates
that the oxidation takes  place directly without formation of
N2O3 as an intermediate.

13652
Ovchinnikova, Ye. N. and O. K. Davmyan
OXIDATION OF SULFUR DIOXIDE ON ACTIVATED CAR-
BON BY THE LIQUID-  CONTACT METHOD. (Ob okislenii
sernistoge angidrida  na aktivirovannoni ugle  zhidkostno-kon-
taktnym  metodom).  Text  in  Russian.  Zh.  Fiz.  Khim.,
30(8): 1735-1738, 1956. 1 ref.
The oxidation of SO2 on the surface  of activated carbon at
room temperature with formation of a definite quantity of ox-
idation product which can be removed  with water in the form
of sulfuric acid was  demonstrated. Above 220 C, the surface-
oxidized product reverts to SO2. As  the quantity of water
sorbed by the carbon increases, the yield approaches a limit of
0.25 g  H2SO4  per gram  carbon. The rate of acid formation
decreases as the acid concentration increases and is  directly
proportional to the square root of the  product of the oxygen
and sulfur dioxide partial pressures.

13802
Lewis, W. K. and E. D. Ries
INFLUENCE OF REACTION RATE ON OPERATING CON-
DITIONS IN CONTACT  SULFURIC ACID MANUFACTURE.
Ind. Eng. Chem., vol. 17:593-598, June 1925. 6  refs.
The data of Knietsch on the conversion of  SO2  to S03 by
platinum  at commercial operating temperatures demonstrates
that the catalytic activity of platinum rises rapidly with the
temperature to about 500 C, then goes  through a maximum at
about 525 C, beyond which it greatly  decreases. The reason
for this maximum is not clear and no experimental data are
available  to confirm it. Operating variables under the control
of an engineer are the composition of the gas entering a con-
verter, operating temperature, and the amount, character, and
distribution of platinum used for a given amount of gas. Equa-
tions based on these conditions were derived to determine the
capacity and efficiency of a converter and the optimum tem-
perature at each stage of converter operation.  They  suggest
that a decided increase in converter efficiency can be obtained
by controlling the temperature of the gases. To achieve this,
converters must  be  modified to absorb the heat of reaction
and the sensible heat of the gases.  Two types  of converters
employing this principle  are suggested. In both, gases reach
the bottom of the converter at about 400 C. The correct tem-
perature gradient for one converter is  maintained by  by-pass
valves. Gases are cooled by coils and contact masses. Gases
passing through the  second converter  are cooled and diluted
by auxiliary air valves. Adiabatic  converters control the tem-
perature. The temperature in the first converter after reaction
can rise to 530 C without losing efficiency; the temperature in
the second to 550 C.

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                                F. BASIC  SCIENCE AND TECHNOLOGY
                                                      35
13875
Pechkovskiy, V. V.
THERMOCHEMICAL  DISSOCIATION  OF  MAGNESIUM
SULFATE. (0 tennokhimicheskom razlozhenii sul 'fata mag-
niya). Text in Russian. Zh. Prikl. Khim., 29(8):1137-1142, 1956.
5 refs.
The rate of thermochemical dissociation of magnesium sulfate
as affected by termperature, time, oxygen content of the gas
passing over the sulfate, and the presence of various metal ox-
ides was studied experimentally to determine the usefulness of
this material as a source for producing acid. Practical dissocia-
tion occurred  at 950-1100 C. Of the additives tested (SiO2,
Fe203, CuO), ferric oxide and cupric oxide  were found to
have a very significant accelerating influence on the dissocia-
tion reaction, this  influence being  always  greatest in the
absence of oxygen (under nitrogen). The data presented will be
helpful in determining additives to be selected for use with this
process.

13940
Davtyan, 0. K. and E. N. Ovchinnikova
INVESTIGATION OF THE MECHANISM OF OXIDATION,
HYDROGENATION   AND  ELECTROCHEMICAL   COM-
BUSTION ON SOLID  CATALYSTS. I. OXIDATION OF SUL-
FUR DIOXIDE ON ACTIVATED CARBON AT 20 C IN THE
PRESENCE OF WATER VAPOR. (Issledovaniye mekhanizma
okisleniya, gidrirovaniya i elektrokhimicheskogo goreniya na
tverdykh katalizatorakh. i. Okisleniye sernistogo angidrida na
poverkhnosti  aktivirovannogo uglya  pir  20  C  v prisutstvii
vodyanykh parov). Text in Russian. Zh. Fiz. Khim., 35(4): 713-
718,1961. 2 refs.
The low-temperature oxidation of sulfur dioxide on the surface
of activated carbon  at 20 C was studied, and a method was
developed  for determining  the  absorption and  oxidation of
S02 when the oxidation product remains adsorbed on the sur-
face. It was found that in the presence of water vapor, the ox-
idation product is held on the surface in the form of sulfuric
acid. As the amount of adsorbed water vapor increases, the
quantity of sulfuric acid absorbed on the carbon reaches some
maximum determined by the partial pressure of oxygen in the
gaseous  phase. Removal  of  the H2SO4 from  the carbon
completely restores its  activity.

14249
Calderbank, P. H.
CONTACT-PROCESS  CONVERTER DESIGN.  Chem.  Eng.
Progr., 49(11): 585-590, Nov. 1953. 9 refs.
An equation was derived to express the rate of SO2 oxidation
with a vanadium oxide catalyst in a flow-type isothermal reac-
tor. The expression is applicable up to 100% conversion for a
variety of commercial vanadium  catalysts and up to 59% con-
version under near-isothermal conditions and can be used to
calculate the weight of a catalyst required to produce a given
amount of conversion.  The units used for the  expression can
be converted into tons  H2SO4 produced/tons catalyst/day, the
loading in tons multiplied by fractional conversion giving the
reaction rate in tons H2SO4 produced at the relevant tempera-
ture and mean partial pressure of SO2, O2, and SO3. Reaction
rate data from other  sources are in broad  agreement with the
proposed equation, which was  applied to an evaluation of
adiabatic converters and converters with integral heat exchan-
gers. Reaction rates, optimum temperature distribution,  and
the required amount of catalyst were determined. An adiabatic
reactor producing 50 tons H2S04 per day requires 14.7 tons of
catalyst for 96% conversion of a feed. A reactor with a heat
 exchanger producing the same amount of H2SO4 requires 0.93
 tons  catalyst  for  96% conversion. The  calculated  optimum
 temperature distribution does not differ greatly from that ob-
 tained in the converter with a heat exchanger.

 14506
 Hull, William Q., Frank Schon, and Hans Zirngibl
 SULFURIC   ACID   FROM  ANHYDRITE.  Mod.  Chem.
 Processes, vol.  5:  123-133, 1958.  12 refs.  (Also: Ind  Eng
 Chem., Aug. 1957.)
 The chemistry of sulfate decomposition and  differences in ce-
 ment clinker production are discussed. The  effect of decom-
 position speed, dependence on temperature and additives,  par-
 ticle  size, and granular size  with gypsum residues from the
 sulfate decomposition were investigated.  In  the industrial an-
 hydrite sulfuric acid process, coke is used as a reducing agent
 and enough aluminum-containing materials are added so  that
 Portland cement is produced  per ton of acid. Dissociation of
 the calcium sulfate consists of three  stages; CaSO4 plus  2 C
 yields CaS  plus 2CO2; CaS  plus 3CaSO4 yields 4CaO plus
 4SO2 (the overall  reduction process is 2CaSO4 plus C yields
 2CaO plus  CO2 plus 2SO2); and 3CaS  plus CaSO4 yields
 3CaO plus 2S2. The CaS and CaSO4 have,  at each tempera-
 ture, a definite decomposition pressure. Additives  of clay or
 similar materials raise the decomposition pressure and the tem-
 perature in  order  to maintain the  same  decomposition rate.
 Too much CaS and CaSO4 also lowers the decomposition rate.
 As far as sulfur dioxide is concerned, this is the end of  the
 process. The  rest involves making  the  cement clinker. A
 further rise in temperature up to  1400 C completes the reaction
 between the components and lime, formed during decomposi-
 tion,  to produce a good clinker. Besides an  exact adjustment
 of the proportions  of the reduction coke to the anhydrite,  the
 proportions  of the added materials to the CaO  and to each
 other must be carefully adjusted within determined limits so
 that a good  clinker results.  Even more important, kiln opera-
 tion must be carried out under  steady conditions.  Heat con-
 sumption for clinker in the  anhydrite  sulfuric acid process as
 compared with that of normal portland cement clinker must
 also be considered. A typical plant and its  contact process  are
 described. Production is inexpensive, and cement  is sold at
 market value.  There was no difficulty in marketing surplus
 acid.

 14526
 Postnikov, V. F., T. I. Kunin, and A. A. Astasheva
 THE  CONTACT CAPABILITY  OF CHROMIC OXIDE FOR
 THE  OXTOATION OF SO2 TO SO3. (O  kontaktiruyushchey
 sposobnosti okisi khroma dlya okislaniya S02 v SO3). Text in
 Russian. Zh. Prikl. Khim., 9(8):1373-1377, 1936. 10 refs.
 The catalytic activity of chromic oxide in the oxidation of sul-
 fur dioxide depends on the  starting materials and the method
 of preparation. Greatest activity was given  by a chromic oxide
 gel precipitated with ammonia on heating;  chromic  oxide gels
 precipitated with sodium or potassium hydroxides had a much
 lower contact property. Water vapor increases the activity of
 pure  chromic  oxide,  shifting the  curve  of contact in  the
 direction of higher  temperatures  in comparison with operation
 in dry gas. Activation of the chromic oxide gel, precipitated by
 ammonia, by the acetates  of calcium, zinc, aluminum,  and
 nickel does not improve the contact properties of chromic  ox-
ide. The activity of chromic oxide precipitated with sodium
hydroxide increases in the presence of activators but does  not
attain the level of activity of pure chromic oxide precipitated
with ammonia.

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 36
SULFURIC ACID MANUFACTURING
 14538
 Boreskov, G. K. and V. P. Pligunov
 KINETICS  OF THE CONTACT  OXIDATION  OF  SO2.
 (Kinetika kontaktnogo okisleniya SO2). Text in Russian. Zh.
 Prikl. Khim., 6(5):785- 796, 1933. 14 refs.
 An isothermal method was developed for the oxidation of SO2
 in a flowing system. The effects of contact time, gas composi-
 tion, and temperature on the oxidation rate of SO2 over the
 vanadium catalyst  'BOV  were studied. The applicability of
 the Taylor  Lenher formula was shown. The apparent  heat of
 activation was determined as 20,000 cal for high temperatures
 and 55,000 cal for low temperatures. The point of inflection
 was at 440 deg. The results were compared with those known
 for a platinum catalyst. It was shown  that for temperatures
 higher than the point of inflection, the course of the reaction
 on platinum and vanadium catalysts occurs almost identically.
 Upon temperature decrease to the point of inflection, the rate
 of oxidation on a vanadium catalyst falls rapidly in proportion
 to the sharp increase in apparent heat of activation to 50,000
 cal. In this temperature interval, the total rate of the process
 determines  the rate of freeing the catalyst  surface from the
 SO3 being formed. On the basis of these conclusions, the
 practical use of vanadium catalysts  is  considered. Formulas
 and diagrams are given, establishing the optimal curve  of tem-
 perature change along the layer of contact mass. This curve
 provides for the maximum rate of the process, shows the time
 of  contact  necessary for carrying out any part of  the oxida-
 tion, and also provides for finding the optimal composition of
 the gas mixture giving maximum productivity under these con-
 ditions.

 14539
 Adadurov, I. E., M. V. Apanasenko, L. M. Orlova, and A. I.
 Ryabchenko
 EFFECT OF THE COMPOSITION  AND DISPOSITION OF
 THE CONTACT MASS ON THE CATALYTIC ACTIVITY OF
 CHROMIUM  CATALYSTS. (Vliyaniye  sostava i raspoloz-
 heniya  kontaktnoy  massy  na  kataliticheskuyu  aktivnost'
 khromovykh katalizatorov). Text in Russian. Zh. Prikl.  Khim.,
 7(8):1356-1362, 1934. 3 refs.
 In spite of  their high quality, chromium-tin catalysts have the
 disadvantage  that the  activating mixture requires unavailable
 amounts of tin. Attempts to decrease the requirement of  cata-
 lytic material by applying  it to a carrier have not  yet led to
 favorable results. Efforts to replace  tin with other activators
 have not produced any promising patents for industrial use.
 Only aluminum oxide at temperatures beginning at 530 deg has
 given a conversion close to the theoretical yield of approxi-
 mately 90%. The maximum increase in the amount of sulfur
 dioxide converted into sulfur trioxide per unit volume of con-
 tact mass using a  chromium-tin catalyst  can be attained  by
 coordinating the reaction with its kinetics and by arranging the
 contact material according to particle size in the contact ap-
paratus.  Arranging the  catalyst particles according  to  the
movement of the gas with the largest particles at the top of the
apparatus increases contact by 4-5%. The  same  kinetic princi-
ples applied to a two-stage contact process  (loading the first
converter with a chromium mass activated with aluminum ox-
ide, operating at 550 deg, the second converter with a chromi-
um-tin catalyst, operating at 450 deg) resulted in a productivity
increased by 250%.  Thus, it appears possible to operate a con-
tact process on a combination chromium catalyst.
                         14625
                         Davtyan, O. K., B. A. Manakin, and E. G. Misyuk
                         TEMPERATURE DEPENDENCE OF  SULFURIC ACID FOR-
                         MATION RATE DURING  CATALYTIC OXIDATION OF
                         SULFUR DIOXIDE ON ACTIVATED CARBON BY THE WET
                         CONTACT METHOD. (Temperaturnaya zavisimost' skorosti
                         obrazovaniya  sernoy  kisloty  pri kataliticheskom  okislenii
                         sernistogo angidrida na aktivirovannom ugle zhidkostno- kon-
                         taktnym metodom).  Text in Russian.  Nauchn.  Ezhegodnik
                         Odessk. Gos. Univ., Khim. Fak., no. 2:113-115, 1961. 2 refs.
                         The formation of sulfuric acid was studied experimentally in a
                         laboratory percolating device in which an incoming SO2-02
                         mixture serves to lift the solvent so  that it trickles over the
                         catalyst before returning  to the solvent reservoir. The partial
                         pressures of the gas mixture were 200 and 400 mm Hg in two
                         series of experiments over 10 deg temperature intervals rang-
                         ing from 0 to 60 C. The temperature coefficient  in all cases
                         varied from 1.2 to 1.3, i.e., within the range typical for a diffu-
                         sion process.

                         14626
                         Chzhi-tsayn, Syao, V. I. Smirnov, and I. T. Sryvalin
                         THERMODYNAMICS OF SULFATE ROASTING OF  CON-
                         VERTER SLAGS IN  A BOILING LAYER. (Termodinamika
                         protsessov   sul'fatiziruyushchego  obzhiga   konverternykh
                         shlakov v kipyashchem sloye). Text in Russian. Tr.  Ural'sk.
                         Politekhn. Inst., no. 98:67-71, 1960. 9 refs.
                         Data from the literature are used to make thermodynamic cal-
                         culations for reactions of  elemental  metals  (nickel, cobalt,
                         copper, iron),  metal sulfides, metal oxides, and metal oxide-
                         silicon dioxide complexes with sulfuric acid and sulfur dioxide
                         at 573-973 K. Isobaric potential is plotted for a number of
                         reactions. Reaction  of metals with sulfuric acid is in  the
                         sequence: cobalt, nickel, copper. Isobaric potentials for reac-
                         tions between metal sulfides and sulfuric acid are  comparable
                         for iron, cobalt, and nickel but considerably higher for copper.
                         The reaction sequence for  the sulfating of metal oxides is
                         found to be: cobalt, nickel,  copper, iron. Sulfating of silicates
                         is characterized by  much more negative isobaric potentials,
                         being nearly the same for iron, cobalt, and nickel. It may be
                         concluded that under  similar conditions, oxides, metals,  and
                         sulfides will sulfate more readily than will silicates,  ferrites,
                         and  aluminates. It is noted that the drop in isobaric potential
                         decreases with increasing temperature in the  case of sulfur
                         dioxide but increases with sulfuric acid, the isobaric potential
                         plots intersecting  at 450-500 C. Hence, sulfation with sulfuric
                         acid will predominate at practicable  roasting temperatures
                         (600-700 C).

                         14641
                         Kapustinksy, A. F.
                         THERMODYNAMICAL THEORY OF  SULPHURIC ACID
                         PROCESSES. Compt. Rend.  Acad.  Sci. URSS, 53(8):719-722,
                         1946. 16 refs.
                         The manufacture of sulfuric acid, regardless of the production
                         method and catalyst  employed, is  based on the  equilibrium
                         reaction SO2 plus 1/2O2  yields  SOS.  With the aid of known
                         specific heats  of  gaseous reagents, equations  for calculating
                         the free energy and heat of the reaction were derived from
                         previously determined equilibrium constants for the formation
                         of  sulfur trioxide from  sulfur  dioxide  and  oxygen  on  a
                         platinum catalyst. Standard  values of  these thermodynamic
                         functions are shown and compared with those contained in the
                         literature. The absolute entropy of liquid sulfuric acid and its
                         heat of formation under standard conditions are given, as well

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                                 F.  BASIC SCIENCE AND TECHNOLOGY
                                                     37
 as  the absolute  entropy of  gaseous sulfur trioxide.  The
 proposed  thennodynamic theory of the sulfuric acid process
 makes it possible to represent as a single system, data  con-
 stituting the basis of all sulfuric acid production methods for
 the oxidation of sulfur dioxide by oxygen.

 14653
 Kapustinskiy, A. F.
 ON  THE  PHYSICOCHEMICAL THEORY OF OBTAINING
 SULFURIC ACID BY THE CONTACT METHOD. (K fiziko-
 khimicheskoy teorii kontaktnogo sposoba polucheniya semoy
 kisloty). Text in Russian. Issled. Po Prikl. Khim., Akad. Nauk.
 SSSR, Old. Khim. Nauk, Sb., 1955:22-38. 38 refs.
 This study examines the formation of  SO3 from SO2 and ox-
 ygen,  the  thermodynamics  of  SO3  synthesis,  and   the
 mechanisms of catalysis in this synthesis. The study of the dis-
 sociation  equilibrium  of SO3   at  high  temperatures  over
 platinum using modern measuring techniques  is described. A
 rigorous thennodynamic analysis of available results, based on
 classical thermodynamics, was made without any assumptions
 or approximations and was found  to be  in  agreement  with
 spectroscopic and  calorimetric  data. A structural-model ap-
 proach is  given  to explain the catalytic  action of platinum,
 proceeding from a proposed deformation of the molecules dur-
 ing adsorption, drawing on data from crystal chemistry and
 new information regarding molecular structure.

 14845
 Streicher,  J. S.
 THE CATALYSIS  OF  SO2 TO  SO3.  Chem.  Met. Eng.,
 37(6):501-502, Aug. 1930.
 The  use of vanadium as a catalyzer in the sulfuric-acid process
 is discussed  as a substitute for platinum. At low  flow rates
 vanadium  achieves the same conversions as platinum at given
 temperatures. The problem with vanadium is reaching the high
 rate  at which the gases can be combined independently of the
 percentage yield. The joint action of the two  factors, highest
 flow rates and highest conversions, is the decisive point of
 every contact plant. The  elimination of platinum and the  sub-
 stitution of  vanadium  compounds and other  catalytic com-
 pounds has  an important  economic aspect. In 1930,  1 kg of
 platinum cost $1286 and 1 kg of vanadium cost $7. The amount
 invested in platinum can be overlooked, considering that the
 additional  cost of patented apparatus,  machinery, license fee,
 and  depreciation  always  offsets the  investment.  The  high
 return  value  of platinum is often in calculations.  Moreover,
 platinum does not cost  'two  thousand  times, as much as
 vanadium', the true  proportion of  the cost of vanadium to
 platinum in July 1930 was 1:184.

 14871
 Graf ton, Raymond William
 PROCESS FOR THE TREATMENT OF GLAUBER'S SALT.
 (Courtaulds  Ltd.,  London) Brit. Pat. 801,527. 9p., Sept. 17,
 1958. (Appl. Jan. 24, 1957, 6 claims).
 A process is claimed relating to the treatment of Glauber's
 salt,  large  quantities of which are obtained as  a by-product in
 the viscose rayon industry, in order to permit  the recovery of
 useful chemicals from the salt. To date, this salt has had  little
 market value. The process comprises dissolving  the salt in
 water,  treating the solution with  an ion-exchange resin to form
sulfuric acid and a  sodium  resin salt, and regenerating the
sodium resin  salt by  treatment with nitric acid. The reactions
involved in  this  process  are RH + Na2SO4 yields NaR  +
1/2H2SO4, and NaR  + HN03 yields RH  + NaNO3, R being
the cation exchange resin. The process is preferably effected
in a cyclic manner. The recovered solutions are sulfuric acid,
which can be used directly in the viscose rayon factory, and
sodium nitrate, which can be used as a fertilizer. In one cyclic
process  of this invention, the ion-exchange resin is contained
in a number of reactors  which are arranged on a turntable,
which moves the reactors  in a cyclic manner so that each reac-
tor moves in turn through four fixed zones. In another cyclic
process, the reactors, instead of being arranged on a turntable,
are fixed, and a single rotary  valve is provided which connects
the various  reactors  to the  correct   liquor feeding  and
withdrawal  points at the appropriate stages in the cyclic
process. The number of reactors in the various zones is deter-
mined by  the  particular  reaction to be  carried  out and  the
degree of conversion required, but in general from two to five
reactors in each  zone  seems to be sufficient for economic
operation. In addition, the speed of rotation of the turntable or
rotary valve and the rate  of feed of the solutions supplied to
the reactors must  be suitably correlated to allow for adequate
reaction times. Technical  details of the process, a sample  ex-
perimental apparatus, and  pertinent diagrams are included.

15325
Suchkov, A. B., B. A. Borok, and Z. I. Morozova
THERMAL DECOMPOSITION OF A MIXTURE OF MnSO4
+ FeSO4 IN A FLOW OF STEAM. (O termicheskom razloz-
henii smesi MnS04 + FeSO4 v toke vodyanogo para). Text in
Russian. Zh. Prikl. Khim., vol.  32: 1618-1620, May-Aug. 1959.
8 refs.
It was established experimentally that the decomposition  of
ferric sulfate in a flow  of steam of 500 C  yields high-quality
ferric oxide and regenerates  a  significant quantity of sulfuric
acid of 96% concentration. Decomposition of a mixture of fer-
ric sulfate and manganese sulfate in a flow of steam at 600 C
followed by washing of the solid product with water yields fer-
ric oxide free of manganese impurities.

15416
Suchkov, A. B., B. A. Borok, and Z. I. Morozova
THERMAL DECOMPOSITION OF CERTAIN SULFATES IN
A FLOW OF STEAM.  (O termicheskom razlozhenii nekoto-
rykh sul'fatov  v toke vodyanogo para). Text in Russian. Zh.
Prikl. Khim., vol. 32: 1616-1618, May-Aug. 1959. 2 refs.
Thermal decomposition at 200-1000 C in steam  was studied
using sulfates of lithium,  sodium, potassium, copper, berylli-
um, magnesium,  calcium,  aluminum, titanium,  chromium,
manganese, iron,  cobalt,  and  tin. It  was  demonstrated that
decomposition of  certain sulfates under these conditions is  an
effective process for obtaining sulfuric acid and corresponding
oxides and  that it proceeds at  much lower temperatures than
ordinary thermal decomposition. A bond-theory explanation is
given  for differences in  decomposition  temperatures among
these sulfates.

16292
Kozhevnikova, N. V. and  D. G. Tracer
PETROGRAPfflC AND X-RAY EXAMINATION OF HtON
OXIDE CATALYST FOR  THE PRODUCTION OF SULFURIC
ACID.   (Petrograficheskoye   i  rentgenograficheskoye   iss-
ledovaniye  okisno-zheleznogo  katalizatora  dlya  proizvodstva
sernoy kisloty). Text in Russian.  Zh. Prikl. Khim., 39(6):1272-
1275, 1966. 6 refs.
Iron oxide catalysts  undergo  partial sulfatization by the action
of sulfur dioxide and sulfur trioxide at 675-750 C. Roasting the
catalyst at 1000 C  leads to the formation of nonactive minerals

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 38
SULFURIC ACID MANUFACTURING
of the iron orthoclase type (aegirite) and solid solutions of iron
oxide with  quartz. Long-term (100 hrs)  treatment  of the
catalyst at high temperatures with insufficient oxygen causes
gradual accumulation of solid solutions of iron oxides with sil-
ica, which subsequently leads to a reduction in catalytic activi-
ty. X-ray data for catalysts prior to and after high-temperature
treatment and after roasting are tabulated.

16377
Rzayev, P. B., V. A. Royter, and G. P. Korneychuk
KINETICS OF SULFURIC ACID CATALYSIS ON BARIUM-
ALUMINUM-VANApIUM  CATALYSTS.  (O   kinetike  ser-
nokislotnogo   kataliza  na  bariyevo-  alyumovanadiyevykh
katalizatorakh). Text in Russian. Ukr. Khim.  Zh., 26(2):161-
167, 1960.  5 refs.
The kinetics of sulfur  dioxide oxidation on barium-aluminum-
vanadium  catalysts were studied and found to conform to  an
equation derived elsewhere by G. K. Boreskov. The heat of
activation  was  23 kcal/mole  and pertained to an internal-
kinetic regime  which  was not distorted by  the effect  of
macrofactors.  Even with  small catalyst grains (1.5-2.0 mm
diameter), conversion  factors below 70%, and temperatures
above 500 C, an internal diffusion retardation occurred which
reduced the  measured heat of  activation. The  activity of the
catalyst remained  practically constant with significant dif-
ferences in the degree of reduction of vanadium oxides in the
catalyst. Possible causes for overestimation of  the heat of ac-
tivation by the diaphragm method were discussed.

20274
Collins, Conrad G., Jr.
A REVIEW  OF SULPHUR FLAME TECHNOLOGY. (PART
2).  Sulphur Inst. J., 6(l):18-22,  Spring 1970. 52 refs. Part I.
Ibid, Winter 1969-70.
The encounter and reaction of sulfur dioxide with an oxygen
atom appears to be  the  predominant mechanism for sulfur
trioxide  formation according to most studies  of  stack gases
and the hydrogen sulfide flame. The mechanism can be impor-
tant only in  flames with high temperature (1200 C) zones for
the formation of atomic oxygen, as at lower temperatures, the
slow homogeneous reaction between S02 and  molecular ox-
ygen appears to be a two body collision reaction. Catalytic ac-
tion of nitric  oxide for oxidizing SO2 to 803 is questioned in
lower temperature regions where SO2 would react only with
molecular  oxygen, but if high temperatures prevail, such that
the oxygen atom concentration is appreciable, the catalytic ef-
fect of  NO  may  be   established.  Experimental  work  with
hydrogen  chloride added  to the flame (nucleophilic  partner)
yielded 38% SO3, and HC1 was viewed as a stabilizing medium
for SO3. Different sulfur  oxide species have  been detected
spectroscopically at a variety of conditions, from low tempera-
ture to the high temperature of shock waves.

21068
Lasiewicz, Krystyna, Aleksandra Pudliszak-Dziewanowska,
and Juliusz Wesolowski
POROUS STRUCTURE OF VANADIUM CATALYSTS FOR
SO2  OXIDATION.    (Struktura   porowata   katalizatorow
wanadowych  do utleniania SO2). Text in  Polish. Przemysl
Chem., 43(3):140-143, 1969. 2 refs.
Vanadium  catalysts used to oxidize sulfur dioxide in the manu-
facture of sulfuric acid were  studied in terms of their  pore
                         structure. The preferred catalyst had pores with a radius larger
                         than 5,000 A. When 90% of the pores exceeded 1,000 A, the
                         activity of the catalyst was fairly high,  while lowest activity
                         was assigned to those with a majority of pores below 1,000 A.
                         For pores ranging in their radius from 75 to  75,000  A, the
                         specific volume was 0.12-0.65 sq cm/g. The range of specific
                         surface was 2.4-6.3 sq m/g.

                         22098
                         Honti, Georges
                         OPTTMALIZATION  OF A SULFURIC ACID PLANT WITH
                         THE AID OF A COMPUTER.  (OptimaKzation  d'une usine
                         d'acid suBurique a 1'aide d'un ordinateur ekctronique). Text in
                         French. Ann. Genie Chun., 1967:206-214, 1967. 28 refs.
                         A computer program to optimalize industrial plant capabilities
                         is presented. The program is of a general  nature and can be
                         adapted to every process and every actual factory. The in-
                         dividual  blocks are  also universally applicable and  can be
                         adapted to actual conditions and data. In the case of calcula-
                         tions relating to a sulfuric  acid factory, the only problem is
                         that of the catalytic converter,  and  the  corresponding op-
                         timalization program is drawn up. A simplified version, used
                         for checking purposes without optimalization, enables the ac-
                         tivity of  the catalyst to be checked  as a function of the  data
                         relating to  temperature,  concentration, and  linear velocity
                         measured in the converter. Working with industrial and labora-
                         tory measurements, this program  can be used to check the
                         validity of a large number of kinetic equations.  The results of
                         some  of  these calculations  are described. (Author abstract
                         modified)

                         22154
                         Stopperka, K. and V. Neumann
                         INFRARED SPECTROSCOPIC INVESTIGATIONS OF THE
                         LIQUID  SYSTEMS SO3-H2O AND  SO3-D20. 5.  THE TEM-
                         PERATURE-DEPENDENT EQUILIBRIA IN  THE  LIQUID
                         SYSTEM   H2SO4-SO3.  (Infrarotspecktroskopische  Unter-
                         suchung an den fluessigen Systemen SO3-H2O und SO3-D2O.
                         5. Ueber die temperaturabhaengigen Gleichgewichte im flues-
                         sigen System H2SO4-SO3). Text in German. Z. Anorg. Allgem.
                         Chem., 374(2):113- 124, May  1970. 11 refs.
                         During investigations of the stability  of sulfuric-acid mists, the
                         necessity arose to obtain accurate data on the temperature-de-
                         penden equilibria  of  the  liquid  system sulfuric  acid-sulfur
                         trioxide. An infrared absorption spectrographic study was car-
                         ried out of H2SO4-SO3 solutions with O to 100% SOS in incre-
                         ments  of  10% (except for one step  with 5% SOS). Tempera-
                         tures increased from 20 C by 10 deg increments up to and in-
                         cluding the respective boiling points. To withstand the chemi-
                         cal attack of the  solutions at the test temperatures, a special
                         cuvette was designed in which the solution to be analyzed was
                         placed in an annular container surrounded by a heating mantle
                         with a thermostatic temperature control. This, in turn is  sur-
                         rounded by and communicates with a hollow, 2.5 micron thick
                         (at 20 C), 25 mm diameter space bounded by two 1 mm thick,
                         25 mm diameter discs of pure silicon and assembled by a very
                         ingenious method.  Sets  of infrared  absorption  spectra of
                         H2SO4-SO3 solutions with 0.5, 40, 50, 80, and  100% SOS are
                         presented graphically. Their correction with the aid of data ob-
                         tained by a compensation cuvette, as well as their interpreta-
                         tion, are discussed at some length. The information provided
                         by the spectra  is  presented tabularly, confirming and supple-
                         menting previous findings.

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                                                                                                                 39
                          G.  EFFECTS-HUMAN  HEALTH
 11379
 Bustueva, K. A.
 TOXICITY   OF  SULFUR   OXIDES   INHALATION   IN
 CHRONIC CONTINOUS EXPERIMENT. In: Biological Effect
 and Hygienic Significance  of  Atmospheric Pollutants, Book
 1/9, V. A. Ryazanov and  M. S. Gol'dberg (eds.), Translated
 from Russian by B.  S. Levine, U.  S. S. R. Literature on Air
 Pollution and Related Occupational Diseases, Vol. 16, pp. 82-
 98, 1968. ((15)) refs. CFSTI: PB 179141
 Prolonged uninterrupted inhalation of air containing a mixture
 of  SO2 and  sulfuric  acid aerosol affected the  organism in a
 synergistic (additive) manner.  In this connection sanitary
 evaluation of the simultaneous presence of SO2 and of sulfuric
 acid aerosol  in atmospheric air of inhabited  areas  should be
 quided by a general formula which is based on the principle of
 simple addition. A formula is proposed as a guide in evaluating
 the sanitary condition of atmospheric air of populated air of
 populated areas which contained SO2 gas and sulfuric acid
 aerosol simultaneously.

 16774
 Amdur, Mary O.
 TOXICOLOGIC APPRAISAL OF PARTICULATE MATTER,
 OXIDES OF SULFUR, AND SULFURIC ACID. J. Air Pollution
 Control Assoc., 19(9):638-646, Sept. 1969. 62 refs.
 An examination of  the available lexicological  literature in-
 dicates  that sulfur dioxide itself would be properly classified
 as a mild respiratory  irritant, the main portion of which is ab-
 sorbed in the upper respiratory tract. The literature further in-
 dicates  that sulfuric  acid and  irritant sulfates,  to the  extent
 that the latter have been  examined, are more potent irritants
 than SO2. The irritant potency  of these substances is affected
 by  particle size  and  by relative humidity, which factors are
 probably interrelated. There is  evidence, based  on animal ex-
 periments of  one investigator,  indicating that the presence of
 particulate matter capable of oxidizing S02 to H2SO4 caused
 a three to fourfold potentiation of the  irritant response. The
 aerosols causing this  potentiation were soluble salts of ferrous
 iron, manganese, and vanadium all of  which would become
 droplets upon inhalation.  Insoluble aerosols such as carbon,
 iron oxide fume, triphenylphosphate, or fly ash  did  not cause
 a potentiation of the irritant of  sulfur  dioxide even when used
 at higher concentrations. The concentrations  of SO2 used in
 these various experiments were in some cases as low as 0.16
 ppm. The catalytic aerosols  were used at concentrations of 0.7
 to 1 mg/m3 which is above any reported levels of these metals
 in urban air.  If the S02 present as an air pollutant remained
 unaltered  until removed  by dilution,  there  would  be no
 evidence in the lexicological literature suggesting thai it would
 be likely to have any effects on man al prevailing levels. Slu-
 dies of almospheric chemislry have shown  thai  SO2 does nol
 remain   unaltered in  the  atmosphere,  but is  converted  to
 H2SO4. Such a conversion  increases  ils irritanl potency. On
this basis, ihe lexicological literature combined with the litera-
 ture  of atmospheric  chemistry  suggest thai sulfur dioxide
levels be conlrolled in terms of Ihe potential formation of irri-
tant particles. Therefore control measures should be, as  far as
feasible,  aimed at bolh SO2 and particulate material and not
against either alone. This article is followed by a discussion by
J. Wesley Clayton, Jr. (Author's Abslracl Modified)

17623
Bushlueva, K. A.
EXPERIMENTAL STUDIES ON THE EFFECT OF LOW OX-
DDES OF SULFUR CONCENTRATIONS ON THE ANIMAL
ORGANISM. In: Limils of Allowable Concenlralions of Al-
mospheric Pollulants. V. A. Ryazanov (ed.),  Book 5, Washing-
ton, D. C., U. S. Public Heallh Service, March 1962, p. 92-103.
7 refs. (Translated by B. S. Levine.)
Sevenly-eighl guinea  pigs approximately  one monlh  old and
weighing belween 150 and 250 g were divided  into groups of
four and exposed  for 120 continuous hours  to low concenlra-
lions of sulfuric acid aerosol and sulfur dioxide, individually
and in combination. A continuous 120 hr exposure to 3 mg/cu
m of SO2 and 1 mg/cu m of sulfuric acid  aerosol produced
pathomorphological changes in the lungs and upper respiralory
passages and brought aboul Ihe appearance of sclerosis two to
three months after exposure discontinuation. Similar  changes
were observed in the lungs and upper  respiratory  tracts in
animals exposed to the combined effects  of sulfur dioxide and
sulfuric   acid  aerosol   in  concentrations   reduced   cor-
respondingly to 1.0 mg/cu  m and 0.5 mg/cu m. Changes in lung
histamine contenl were  observed and suggesl the possible role
of  this  subslance in Ihe palhogenesis and  clinical  sympto-
matology frequently witnessed during London smogs.  Dala ob-
tained in the investigation, support the contention of  other in-
vestigators thai SO2 is  the leading agent in  the London smog
formation.

22594
Bushtueva, K. A.
NEW STUDffiS ON  THE EFFECT  OF  SULFUR DIOXIDE
AND OF SULFURIC ACID AEROSOL ON REFLEX ACTIVI-
TY OF MAN.  In:  Limils  of Allowable Concentrations of At-
mospheric Pollutanls.  Book 5, V. A. Ryazanov  (ed.),  p. 86-92.
Translated from Russian. B. S. Levine, March 1962. 2 refs.
Data on the threshold reflex activity of simultaneously present
sulfur dioxide  and sulfuric  acid aerosol were  gathered by a
direcl continuous recording  of Ihe effecl of  inhalation of Ihe
gases on  Ihe  cerebral cortex.  Onsel of electrical  activity
desynchronizalion, or alpha-rhylhm suppression, was laken as
Ihe index of positive response. Sulfur dioxide broughl aboul a
well-defined desynchronizalion al 0.9 mg/cu  m concenlration.
When combined  wilh  lighl,  sulfur dioxide stimulated  the
developmenl  of conditioned reflexes.   In  such inslances,
desynchronizalion effecl  were  even more  pronounced. The
maximum sulfur dioxide  concenlration  eliciting conditioned
reflexes  was 0.6 mg/cu  m. In olher experimenls, lesl  subjecls
inhaled sulfur dioxide  in  sublhreshold  concentrations,  with
light Ihe  conditioned  stimulator. After 19 associated  applica-
tions, ihe reflex manifested ilself even in Ihe  absence of sulfur
dioxide, indicating  that sulfur dioxide continues to  stimulate
reflex activity despite  the extinction of Ihe primary visible

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40
SULFURIC ACID MANUFACTURING
reaction.  Incidental  application  of  sulfuric  aerosol  in
subthreshold concentrations elicited no electrical cerebral ac-
tivity changes in the form of desynchronization. Where 0.63
mg/cu  m,   or   threshold  concentrations,   were   used,
desynchronization lasting only  1-2  seconds  was  observed.
However, when a 0.4 mg/cu m subthreshold concentration was
used  as a conditioned stimulator,  with light the conditioned
reflex reinforcing agent, a fully conditioned reflex eventually
developed. This  suggests  that subthreshold  odor perception
concentrations of sulfuric  acid  aerosol can  be  used  in
establishing changes in cortical activity as recorded on an elec-
troencephalogram.

23930
Clayton, J. Wesley, Jr.
BIOLOGICAL EFFECTS OF SULFUR DIOXIDE AND  FLY
ASH. Edison Elec. Inst. Bull., 38(7):222-225, July-Aug. 1970.
(Presented at the Edison Electric Institute, 38th Annual Con-
vention, Boston,  Mass., June 2, 1970.)
Experiments were undertaken to determine the  biological ef-
fects on monkeys and guinea pigs of several concentrations of
sulfur dioxide, sulfuric acid mist, and fly ash, as well as mix-
                         tures of these materials. In all of the measurements employed
                         to assess lung performance, no adverse effects were discerned
                         when guinea pigs inhaled  0.1,  1.0, or 5.0 ppm of SO2 in fil-
                         tered  air. In fact, as shown by carbon monoxide uptake, the
                         guinea pigs breathing 5.0 ppm SO2 showed a greater ability to
                         effect the diffusion of oxygen and carbon dioxide across lung
                         membranes than all the animals including the controls. When
                         the investigation was terminated  after one year,  the guinea
                         pigs  exposed  to 5.0  ppm  evidenced  a reduction   in  the
                         prevalence and severity of the lung changes which are  the nor-
                         mal accompaniment of  age in these animals. A slight increase
                         in the size  of the liver cells was  observed, as well as an in-
                         crease in liver cell vacuoles. Sulfur dioxide concentrations of
                         0.1, 0.5, and 1.0 ppm imposed no detriment on monkeys as in-
                         dicated  by  body  weight,  lung  function,  blood   studies,
                         biochemical measurements, or microscopic examination of tis-
                         sues.  However,  an  accidental overexposure of 200  to  1000
                         ppm SO2 for about 60 minutes was responsible for a deteriora-
                         tion of lung function and an apparently lowered oxygen-carry-
                         ing ability of the blood.  Studies on  fly ash participates  in
                         which monkeys were exposed to 0.1 or 0.5 mg/cu m indicated
                         no adverse effects of the 18-month exposure.

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                                                                                                              41
                               I.  EFFECTS-MATERIALS
20820
COMMUNITY AIR QUALITY  GUIDES:  SULFUR  COM-
POUNDS. Am. Ind. Hyg. Assoc. J., 31(2):253-260, March-April
1970. 26 refs.
The major sulfur compounds detected in the atmosphere are
sulfur dioxide, sulfur  trioxide,  sulfuric acid,  sulfates, and
hydrogen sulfide.  The  chief  effects  of  SO2  are eye and
respiratory tract irritation, and increased pulmonary resistance.
At concentrations of 87 mg/cu m for 2.75 hours, SO3 proved
fatal to guinea pigs. Hydrogen  sulfide is a respiratory and eye
irritant at low concentrations,  and at high concentrations can
cause respiratory  paralysis.  It is believed  that sulfur com-
pounds produce a more severe effect when they are adsorbed
on a particle small enough to penetrate the lung. Sulfur oxides
and hydrogen sulfide can also damage vegetation. Materials
such as metals, paper, leather, textiles, paint, and ceramics are
also  damaged by sulfur compounds.  It is suggested that the
sulfur oxide concentration in the air kept as low as  possible to
prevent damage to  vegetation, deterioration  of materials, and
to avoid the  presumed  adverse  health effects. Methods for
sampling sulfur compounds  and  their physical  and chemical
properties are also included.

24160
Maeda, Seiichiro, Hiromi Hasegawa, and Hiroya Watanabe
A NEW METHOD  OF TREATMENT OF SULFUR DIOXIDE
ABSORBING  SOLUTION. (Aryusangasu kyushueki no shori
hoho). Text in Japanese. (Steel  Manufacturing Chemical Indus-
tries (Japan)),  Japan. Pat.  Sho 37-9451  3p., July 27,  1962.
(Appl. Sept 3, 1960, claims not given).
The dilute sulfur dioxide discharged from sulfuric acid plants
or ore refineries  is removed by  absorption  in  ammonium
sulfite  solution. The concentrated solution of sulfur dioxide
thus formed is  added to sulfuric acid and regenerated. In this
process of recovering sulfur dioxide, ammonium sulfate is also
recovered.  Normally,   minute   amounts  of   ammonium
thiosulfate and ammonium  polythionite are contained in the
solution,  causing corrosion  of the container. The  present in-
vention is concerned  with  abating  the  corrosion. After
establishing that corrosion was primarily caused by the two
ammonium salts, it was found that the rate of decomposition
of the salts was a function of acid concentration, temperature,
and time. The decomposition is a one-molecular reaction that
decreases  corrosion  when these  three factors are satisfied.
Container corrosion was almost completely negligible when an
ammonium sulfite-SO2 solution was heated with excess sul-
furic acid, so  the potassium dichromate consumption  was
below 0.002 mol/1. In a sulfuric acid manufacturing factory,
the sulfur dioxide absorbing solution contained 7-9% ammonia
and 25-33% free  sulfuric acid. The result of a corrosion test
showed 10-15 g/sq m/nr. When the solution was kept  at 90 C
for 3 hours and at an acid concentration of 10 N,  ammonium
thiosulfate and ammonium  polythionite were reduced below
0.0004  mol/1 in terms of potassium dichromate consumption.
As a result, corrosion was reduced to 1.2-1.5 g/sq m/nr, which
was negligible.

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42
                                J.  EFFECTS-ECONOMIC
11791
A STUDY OF PROCESS  COSTS  AND ECONOMICS OF
PYRTTE-COAL UTILIZATION. Little (Arthur D.) Inc., Cam-
bridge, Mass, and Dorr- Oliver, Inc., Stamford, Conn., Con-
tract PH 86-27-258, 251p., March 1968. CFSTI: PB 182303
The  economics  of utilizing  iron pyrite (FeS2) from coal
beneficiation were investigated; the prices that might be paid
coal operators for low-sulfur coal and an acceptable grade of
pyrite feed material for use in sulfuric acid manufacture were
determined. The net financial benefits to operators are esti-
mated at $1.16 to $1.57 per ton of coal processed. A premium
of $1.10-$1.20 per  ton of coal should be paid by  nonutility
users and by utilities  subject  to stringent air pollution  abate-
ment restrictions.   Of  this  amount,  approximately  $0.30
represents  the net  value of the coal to a user; the balance
represents the premium connected with achieving lower sulfur
content  in  the stack gas and reduced sulfur dioxide pollution
of the atmosphere. It is emphasized that considerable tonnages
of pyrite-bearing coal must be processed to support a 1500-
ton-per-day sulfuric acid plant. Assuming a  feed stream con-
taining 85% pyrite, a requirement of 1550 pounds of feed per
ton of 98% acid produced,  an original sulfur content of 4%,
and a coal yield of 90%, 5.1 million tons/yr of coal will have to
be beneficiated to  yield 1%  sulfur-content  coal. Investment
and operating costs have been calculated for every combina-
tion  of the three major variables associated with sulfuric acid
production: plant capacity, feed composition, and plant type.
The results show manufacturing costs to be $5.51 to $25.40 per
ton of acid and plant investment, $3.7 to $35.5 million.

17203
Dels, Heinriche
AIR POLLUTION  PROBLEMS IN  WEST GERMANY AND
THE  ROLE OF INDUSTRY.  (Luftforurensningsproblemer i
Vest-Tyskland industriens innsats).  Text in  Norwegian. Tek.
Ukeblad (Oslo), 116(45): 1245-1247, Dec. 1969.
West Germany has been occupied  in the last decade with
reducing emissions  of dust and smoke. Effectiveness of dust
filters has increased threefold, and filtration is more economi-
cal. The dust content can now be reduced to 150 mg/cu m for
an emission rate of  100,000  cu m/hr. In 1950, the dust output
from  the  West German  cement industry was 3.5%  of the
clinker produced; in 1967, it was 0.15%. Dust output from the
manufacture of calcium carbide was  reduced to 3 mg/cu m of
exhaust  gases. Attention now centers on reducing sulfur diox-
ide emissions. An electric power plant in Essen absorbs it with
a new type of activated carbon, recovering the SO2 for the
manufacture of H2SO4, the cost per 1000 kWh being about 1
DM (25  cents), and this can be further reduced. Government
standards now limit the sulfur content  of fuel oils to 1.8%.
About 20% of the total SO2  emission in West Germany comes
from sulfuric acid plants. A new 'double  contact' process can
reduce S02 emissions  of such a plant from 17 to 3 kg per ton
of H2SO4 produced. Nitrogen oxides emitted from nitric acid
plants have been reduced  by 50%  with special absorption
equipment.  New legislation sets a  maximum  average of  2
mg/cu m for fluorine  emissions, or 5 mg for short  intervals.
Readings as high as 2.7 mg have been recorded above the
Ruhr from January 1, 1966, to December 31, 1968. During that
period,   industry   in   North   Rhine-Westphalia   invested
4,000,000,000 DM on air pollution problems related to existent
operations and about 275,000,000 DM on those related to new
ones.  Exhaust  purification  for  the  2-year  period  cost
3,000,000,000 DM, plus  an additional 30,000,000 for  research
this  in  comparison  with   a  gross  national  product  of
300,000,000,000 DM per year. The total amount spent by in-
dustry  is  small  compared with  the  damage  caused, which
amounts to 50 DM per  capita per year, or 3,000,000,000 for
the entire republic, not including losses due  to  sickness  or
sanitation problems.

21206
Schwartz, Irvin
ENVIRONMENTAL CONTROL. Chem. Week, 106(24):79-86,
June 17, 1970.
Methods and costs of air pollution control  are reviewed with
emphasis on the efforts  of the chemical processing industry.
The magnitude of the task is shown by Public  Health Service
estimates of  the  amount of pollutants poured  into  the at-
mosphere each year: particulates,  15  million tons; sulfur ox-
ides, 30 million tons; hydrocarbons, 24 million tons; carbon
monoxide, 87  million tons; nitrous oxides, 17 million  tons.
Within the chemical processing industry,  the percentage  of
capital  outlay for air pollution control equipment is expected
to remain constant, but the kind of equipment is expected to
change. Expenditures for particulate controls account for more
than one-third of  industry  expenditures.   Gaseous emission
controls, currently  less than 2% of sales, is expected to jump
to 40% following development of Federal gaseous emission
criteria. The Health, Education, and Welfare Dept. guidelines
for air quality criteria issued to date are listed. The cost  of
compliance with the HEW 'suggestions' are estimated. For the
sulfuric acid industry, this estimate is $26-39 million capital ex-
penditure and $1.5-2.8  million/year operating  cost.  For the
phosphate fertilizer industry, the estimates are $3.1-6.7 million
and $1.3-2.7  million. The four basic means of collecting par-
ticulates, fabric filter, electrostatic precipitator, cyclones, and
scrubber are described,  along with their capabilities and  cost.
The  three  basic  systems  for  gaseous   emission  control,
scrubbing, adsorption, and incineration  are similarly treated.
By-product recovery is evaluated as a means of reducing the
effective cost of air pollution control. In contradiction to the
National Research Council-National Academy of Engineering's
statement 'commercially  proven technology for control of sul-
fur oxides from combustion processes does not exist', half-a-
dozen  sulfur  oxide-sulfuric  acid  conversion  processes are
listed.

21308
Ferguson, F. A., K. T. Semrau, and D. R. Monti
SO2  FROM  SMELTERS:   BY-PRODUCT  MARKETS  A
POWERFUL LURE. Environ. Sci. Technol., 4(7):562-568  July
1970.

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                                             J.  EFFECTS-ECONOMIC
                                                       43
The non-ferrous smelting industries currently recover less than
one quarter of the sulfur in the ores treated by the 26 smelters
west of the Mississippi. The rest, almost 1.6 million  long tons
of sulfur a year,  is being emitted as sulfur oxides.  Pollution
control could be advanced significantly if smelters could make
and market any of the following by-products: elemental sulfur,
sulfuric acid, liquid sulfur dioxide, and ammonium sulfate (or
bisulfite). The results of an analysis of the potential market are
reported. The total market for liquid sulfur dioxide in the
western United States  is so small that no market or producc-
tion data was developed. The  1970 cost of producin  elemental
sulfur at the smelter (45-100 dollars per ton) provides little op-
portunity to complete with Frasch mine produced products at
10-30 dollars. Sulfuric acid with its smelter-produced  cost of 4-
25 dollars per ton can complete as long as transportation costs
are held to a minimum. This requires that the market  be within
a few hundred miles of the smelter. Even with this stipulation,
the total market including potential growth through 1975 could
absorb only 40% of the potentially producible sulfuric acid.
Emission  reductions of 60-65% could be obtained. Together
with the current and potential market for ammonium sulfate,
an emission reduction of 65-70% is possible.

22397
SULFUR  THAT  GETS AWAY.  Chem.  Week,  98(21):26-28,
May 21, 1966.
Several processes under  development for recovering sulfur
now emitted in stack gases are noted; this potential resource is
related to a present shortage of sulfur for industrial use in the
U. S. and other areas. A major cause of the shortage is the in-
creasing demand due to new foreign and domestic capacity for
sulfuric acid and fertilizer. Sulfuric acid producers are hardest
hit by the shortage.  U. S. governments efforts to discourage
rising sulfur prices are outlined. Drilling of offshore sulfur
deposits  is receiving increasing attention, and  a worldwide
search for more sulfur from a variety of sources is underway.

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44
                       K.  STANDARDS  AND  CRITERIA
06349
AMBIENT Am QUALITY OBJECTIVES - PART 500 (STATU-
TORY  AUTHORITY: PUBLIC HEALTH LAW.  1271, 1276).
New York State Air Pollution Control Board, Albany, Dec. 11,
1964, 11 pp.
Ambient air quality objectives are tabulated for various pollu-
tants. The objectives vary according to subregions  which are
determined by land use. Included is a list of references for the
sampling and analytical methods employed in the measurement
of particulates,  sulfur dioxide, hydrogen disulfide,  fluorides,
beryllium, oxidants, carbon monoxide, and sulfuric acid mist.

19750
Pennsylvania State Dept. of Health, Harrisburg, Air Pollution
Commission
PENNSYLVANIA  AMBIENT  AIR QUALITY STANDARDS.
6p., Oct. 20, 1969. 10 refs.
Annual, 30-day, 24-hr and/or  1-hr air quality standards are
given for  12  pollutants (suspended and settled  particulates,
lead beryllium, sulfates as H2SO4, sulfuric acid mist, fluorides
as HF,  sulfur dioxide, nitrogen  dioxide,  oxidants, hydrogen
sulfide, and carbon monoxide) in  accordance with the require-
ments of the Pennsylvania Air Pollution Control  Act of 1960.
These standards, which will be reviewed at least  once a year,
are for  single-point measurements; they represent  minimum,
and not necessarily desirable quality. The 24-hr  standard for
SO2 is  0.10  ppm; for suspended  particulates, 195  micro-
grams/cu m. An antidegradation policy is stated to  the effect
that where present air quality is  significantly higher than the
established standards, the difference will be conserved, based
on a long range forecast of probable land and air uses in areas
of high air quality. Sampling and analytical procedures  to be
employed for  measuring ambient levels are specified for each
of the 12 pollutants.

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                                                                                                                 45
                     L.  LEGAL   AND  ADMINISTRATIVE
05407
T. Toyama
AIR POLLUTION AND  HEALTH IMPEDIMENT. Japan J.
Ind. Health (Tokyo) 8, (3) 45-8, Mar. 1966. Jap. (Presented at
the  39th Annual  Meeting,  Japan  Society  of  Industrial
Medicine, Ube, Japan, Apr. 7-9,  1966.)
The 39th  Annual Meeting of the Japan Society of Industrial
Medicine was held on April 7-9, 1966 in Ube, Yamaguchi-ken,
Japan. The theme of one of the symposia was planning pro-
grams for air pollution control in  which air  pollution  and
health impairment and the engineering and practice of air pol-
lution control  were discussed. The main  health impairments
covered  deal  with effects of  pollution  on the  respiratory
system and acute diseases resulting therefrom. Prior to World
War II there were no legal problems in pollution control but
by 1963, it was necessary to establish laws covering soot and
dust control. City planning and building restriction ordinances
have come into effect. Dust and soot fall have decreased by
one-sixth  in the past  sixteen  years. Millions of dollars have
been paid by factories and industries for the establishment of
dust collectors and SO2 counter-measures. Waste gas disposal
in nitric and sulfuric acid plants has been brought under con-
trol since 1964. Re-use of the waste gases has  played an im-
portant role in  the economic feasibility of air cleaning.

10998
Putnam, B. and M. Manderson
IRON PURITES FROM HIGH SULFUR COALS. Chem. Eng.
Progr. 64(9):60-65, Sept. 1968.
The major sources of SO2 emission are coal fired  power
generation facilities, followed by other industrial facilities and
space heating.  It  also appears that power plants will become
increasingly important potential contributors of SO2 emissions.
Therefore, reduction  of  emissions  from  coal  fired  power
generation facilities  is of principal  concern.  The National
Center for Air Pollution  Control authorized  two  commercial
firms to  investigate  the  economics of utilizing  iron  pyrite
(FeS2) obtained  from coal beneficiation,  such  as  in sulfuric
acid manufacture. The evaluation includes technical, market-
ing, and economic considerations and emphasizes  the three
major coal producing regions in the U. S. believed to have sig-
nificant quantities of pyrite associated with the coal: central
Pennsylvania, southern Illinois, and northeast Ohio.

11242
M. C. Manderson
SULFUR  OUTLOOK  INTO  THE EARLY  1970'S. Preprint,
Arthur D. Little, Inc.,  Cambridge, Mass.,  ((28))p., 1968.
(Presented at the  61st Annual Meeting, American Institute of
Chemical Engineers, Symposium on Sulfur, Sulfuric Acid and
the Future, Part I, Los Angeles, Calif., Dec.  1-5, 1968, Paper
5-A.)
In 1967, the  United States consumed 9.3 million long tons of
sulfur equivalent.  Ninety percent of the total amount of sulfur
consumed was in  the form sulfuric  acid. The major end uses
of  sulfuric acid  were used  in  producing  nitrogenous  and
phosphatic fertilizers. The Free World increase in sulfur con-
sumption has been higher than that of the United States since
1950, 51% per year compared with 3.6% per year. Over  the
next seven years Free World consumption is expected to grow
at 5% per year, from the 1967 level to 36 million long tons to
39 million long tons. About 5.5 million long tons of new sulfur
capacity will emerge outside the  United Sates over the next 2
1/2 years. Sulfur production in U. S. will grow from the 1967
level of 9.3 million long tons to 14.1 million long tons by 1970
and to 15.8 million long  tons by 1975. The amounts of sulfur
from lower cost sources  will be  adequate to  meet U.S. needs
by 1970,  including net exports of one million tons per year. It
is believed that sulfur prices will seek lower levels which  are
more in line with mimimum return requirements.

24033
Damon, W. A.
THE  CONTROL  OF   NOXIOUS   GASES  AND  FUMES
DISCHARGED   FROM   INDUSTRIAL   UNDERTAKINGS.
World Health Organization,  Copenhagen (Denmark), Regional
Office for Europe, Proc.  Conf. Public Health Aspects Air Pol-
lution Europe, Milan, Italy,  1957, p. 103-130.  26 refs. (Nov. 6-
14.)
The greatest contribution to  air pollution arises from the  com-
bustion of fuel for domestic and  industrial purposes and  from
motor traffic. Its damaging effects  include injury to plants,
deterioration of property, and possible or  proven hazards to
the health of humans and animals. British air pollution legisla-
tion is embodied mainly in three Acts of Parliament: the Alkali
etc. Works  Regulation Acts, first enacted in 1863; the Public
Health Acts, 1936; and the Clean Air Act,  1956. Evolution of
the chemical  industry has  caused a variety  of  changed and
new pollutants. Fluorine compounds  can be washed in alkaline
solutions, followed by electrical  precipitation. The escape of
SO2 from the exits of sulfuric acid plants depend on the effi-
ciency with which the the process is conducted.  In four  stage
contact plants burning brimstone, recourse to scrubbing the
exit gas with either soda or ammonia may be necessary. Power
stations remove SO2 from waste fuel gases by scrubbing with
slightly alkaline water. Sulfur dioxide arising from the roasting
of copper as in the production of iron oxides is normally ab-
sorbed by  passage  through towers  packed  with limestone.
Hydrogen chloride may be recovered  at a useful strength by
arranging a counter current series of absorbers. Hydrogen sul-
fide may  be scrubbed with caustic soda to produce sodium sul-
fide; it may be  absorbed by passage through hydrated iron
oxide which can be regenerated  to produce spent oxide con-
taining up to 50% sulfur;  or it can be stripped out by means of
a solvent and regenerated in concentrated form for treatment
in a Claus Kiln. Gases containing chlorine may be scrubbed
with an  alkaline solution or by contact with milk  of  lime;
passage through a tower  packed  with scrap iron is also effec-
tive. Nitrogen peroxide may be recovered in the form of  nitric
acid by  water  washing; but for every three  molecules of
nitrogen  peroxide thus   absorbed there is  evolution  of one
molecule  of nitric oxide which must be reoxidized to nitrogen
peroxide.

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46
SULFURIC ACID MANUFACTURING
25520
Wright, G. A.
ENVIRONMENTAL  POLLUTION.  J.  New  Zealand  Inst.
Chem., 34(5): 171-179, Oct. 1970.
A condensed account of four speeches which were presented
at a symposium on Environmental Pollution in Auckland, May
12,  1970 are given,  together with a brief  summary of the
discussion.  The concern today with total  quality  of  our sur-
roundings is not merely with pollution  of water  by  sewage,
toxicants, nutrients and other unwanted materials, nor with air
pollution by industrial  and other gaseous or smoky garbage
escaping  into the  atmosphere; the world  is becoming con-
cerned also about noise and heat  pollution and  the general
man-made changes in our surroundings which frequently bring
deterioration in living. Air pollution legislation in New Zealand
                         requires scheduled chemical  processes to employ the 'best
                         practicable means' to control  the discharge of pollution to the
                         atmosphere, but there  have been criticisms of the effective-
                         ness  of such  legislation  when compared with,  for example,
                         legislation that specifies emission standards. In New Zealand,
                         animal  dropping from nearly  sixty-million sheep, from eight-
                         and-a-half million cattle, and from over half a million pigs will
                         be spread on the ground for a long time to come and much of
                         this will be washed by rain into the waters. There must be a
                         tripartite compromise between the natural desire of the public
                         to enjoy an unpolluted atmosphere; the legitimate aspirations
                         of industry to avoid unremunerative expense;  and national
                         health and global rights,  requirements and interests. To take
                         one particular  example  to illustrate improvements in technolo-
                         gy, mention is made of a contact sulfuric acid plant with  the
                         Chatelier principle having been applied to it.

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                                                                                                               47
                                           N.  GENERAL
04845
H. C. Wohlers
SULFUR OXIDES AS AIR POLLUTANTS. Preprint. 1965.
Air pollution by sulfur oxides, SO2 in particular, is reviewed
in its various aspects. Health effects of SO2 include respirato-
ry ailments which can occur to a greater or lesser degree, de-
pending upon concentration of the gas  in the air  and the
susceptibilities of those effected. Air concentrations of less
than 0.3 ppm are considered harmless to  vegetation; the ef-
fects of higher concentrations result from the interaction of
such factors as time and environment with concentration. The
corrosive effects  of SO2 and H2SO4 aerosols in urban areas
are particularly noticeable in materials deterioration. H2SO4
aerosols play a part in visibility reduction in urban air. Based
upon  an estimate  of  390,000,000  tons of sulfur per  year
deposited as sulfate in rain, 30% of the sulfur emissions are
considered to be man-made. Precipitation is the most efficient
process  by  which sulfur is removed from the air. Guidelines
for better control of this problem are suggested.

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                                        AUTHOR  INDEX
                                                                                                               49
 ADACHI N  »B-23264
 ADADUROV I E  'F-14539
 AMDUR M 0 *G-16774
 AMELIN A G 'B-19682, B-24256
 ANGHEL P  B-15739
 ANON  'B-11146
 APAKHOV I A   B-23070
 APANASENKO M V   F-14539
 ARGENBRIGHT L P  *B-21309
 ARKHIPOV,  A S  'B-06282
 ASANO T  *B-24673
 ASTASHEVA A A   F-14526
 AVDEYEVA  I V  B-23070
 AVERBUKH T D 'B-23070
 AVY, A P  'B-03129


                  B

 BACON R  F  *B-19886
 BAKINA N P  B-23070
 BARTON S C 'C-22645, 'C-25445
 BASARGIN, N N 'C-09295
 BEIGHTON,  J  'B-07925
 BENCOWITZ I   B-19886
 BERL, E  F-10907
 BERLY E M  *B-24110
 BILLINGS, C E  *B-07552
 BLINOVA  N  P   B-23070
 BONDARCHUK T P  B-16291
 BOONE, R E  C-00482, *C-01819
 BORESKOV G K  'B-16480, 'F-14538
 BOROK B  A   F-15325, F-15416
 BOYTSOV, A N   B-06282
 BRICE, R M  C-01819
 BRINDUE  L   B-15739
 BRINK J A JR  *B-25717, *B-26095,
      C-23771
 BRINK, J A JR   'B-00587, 'B-11235
 BROOMHEAD F  B-25643
 BROWDER T J JR  *B-24103
 BULICKA  M *B-13206
 BURBA A  A  B-23070
 BURGESS  W D   'B-19606
 BURGGRABE W F   B-26095
 BURGGRABE, WF  B-00587, B-11235
 BUSHTUEVA K A  *G-17623, *G-22594
 BUSHTUEVA, K A  *G-11379
CADA V   B-25768
CALDERBANK P H  *F-14249
CARES, JW  »C-11140
CHZHI TSAYN S  'F-14626
CLAUS, K E   B-09559
CLAUSS N W  'B-23556
CLAYTON J W JR  'G-23930
COLLINS C G JR  'F-20274
CONNOR  J M  *B-17053
COTHAM, R L  'B-05514
COUGHANOWR, D R  'F-04626
CRAWFORD H L  A-21221
CRIDER, W L  'C-00381
CUFFE, S T  *B-02355
CUNNINGHAM G H  'A-13596


                 D

DAMON W A 'L-24033
DAVMYAN 0 K  F-13652
DAVTYAN O K  *F-13940, 'F-14625
DEAN, C M  B-02355
DOERR K H   B-19228, B-24628
DONOVAN J R  *B-25133
DRECHSEL H  *B-19228, *B-24628
DUBOIS L  *C-15745
DUFF, G M  C-09369
DUKES, R R  *B-11238
 EMICKE K  *B-13337
 FAIRS G L  *B-24695
 FARKAS, M D   B-11238
 FARRAR G L  *B-24246
 PELS M  'A-21221
 FERGUSON F A  'J-21308
 FIRST M W  B-24110
 FITT T C  B-15991
 FLEMING E P  *B-15991
 FOHL J  B-21703
 FRANZ M 'B-25491
 FULTON C H  'A-25605
 FURKERT H  'B-20670
GANZ S N  'A-13403, 'B-19370
GARBATO C  'B-17887
GIBSON, F W  'A-10749
GLOWIAK B  *B-25468
GOSTOMCZYK A  B-25468
GRAFTON R W  'F-14871
GREEN, W D 'C-09633
GREENWELL, L E  B-00587, B-11235
GRIM H   B-24628
GRIMM H   B-19228
GRODZOVSKIY M K  'B-19943
GUYOT G   B-11629, 'B-13728, 'B-14030
GUYOT, G L  *B-09913


                 H

HAJEK J  B-13206
HAMMOND R  'B-22943
HARA H  *B-19486
HASEGAWA H  1-24160
HASHIMOTO S  B-23264
HAYASHI, M  'C-03035
HEILINGOETTER R 'C-24970
HENSINGER, C E  'B-09559
HERZOG G  *B-14660
HISHINUMA Y  B-20777
HOEGSTROEM, U  'E-10751
HONTI G  'F-22098
HSUEH L   B-26254
HULL W Q 'F-14506
IRELAND F E
IRELAND, F E
'A-23044
•A-12633
                 J
JACKSON A   B-19469
JAGER L  B-17810
JEPHSON A C  A-13596
JUTZE, G A   C-00482


                 K

KANGUN I  'C-17700
KAPUSTINKSY A F  'F-14641
KAPUSTINSKTY A F  *F-14653
KATZ M  'E-21791
KERRIGAN, J V 'C-01387, *D-05152
KIMURA M   B-23264
KLIMECEK R   B-17810, B-25491
KOHEN, E S   'C-03852
KORNEYCHUK G P  F-16377
KOSHI, S  C-03035
KOSINKSI K   C-20595
KOSSOVSKII, E O  'B-04067
KOTO K  *B-15846
KOZHEVNIKOVA N V 'F-16292
KRAUSE, F E   F-04626
KROUSE, M   B-05079
KUNIN T I  B-19856, F-14526
KURKER, C JR  B-07552
KUZNETSOV I E   B-19370
KUZNETSOV I Y   A-13403
LARRAT P  *C-21415
LASIEWICZ K  'F-21068
LASTOCHKIN Y V 'B-16291
LEHLE W W  'B-13667
LEIKIN L I   B-19370
LEITHE, W  'B-07535
LESOKHIN I G  B-16291
LEWIS W K  'A-13841,'F-13802
LEYKIN L I   A-13403
LINDAU L  'A-18305
LOUISE J  C-21415
LUNGE, G  *F-10907


                M

MAEDA S  '1-24160
MANAKIN B A  F-14625
MANAKIN, G A   B-08181
MANDERSON, M  L-10998
MANDERSON, M C  'L-11242
MAYDUROVA O V  B-23070

-------
50
SULFURIC ACID MANUFACTURING
MAZIARKA S   C-20595
MCADIE H G   C-22645, C-25445
MEINHOLD, T F  *B-03945
MISIAKIEWICZ Z  C-20595
MISYUK E G   F-14625
MOELLER, W  *B-09126
MONKMAN J L   C-15745
MONTI D R  J-21308
MORASH, N  *B-05079
MOROZOVA Z I  F-15325, F-15416
MUKHLENOV I P  B-16289, B-16290,
     B-16291, B-20024


                 N

NAGIBIN V D   *B-23939
NAKAZONO T  'B-25742
NASH T  "C-25851
NEGHERBON, W O  'F-00530
NEUMANN V   F-22154
NILSSON F 'B-25275


                 O

O KEEFFE A E  *C-12596
DELS H  *J-17203
OLEINIKOVA, N K   C-09295
OLEVINSKIY M I  B-14568
ORLOVA L M   F-14539
OSMUL KEVICH V A  B-24256
OVCHINNIKOVA  E N   F-13940
OVCHINNIKOVA  Y N  'F-13652
PATTON W F  "C-23771
PECHKOVSKIY V V  *F-13875
PERRINE R L  'B-26254
PETERSSON S  *B-24451
PETROVSKIY V A   B-24256
PIATTIL  A-23972
PLIGUNOV V P  F-14538
PODMOLIK J  B-13206
POL YAK, V E  *D-11492
POPOVICI N  *B-15739
POPPELE E W  B-24833
POSTINIKOV V F *B-19856
POSTNIKOV V F  *F-14526
POTOP P  B-15739
PREBLE B  B-21309
PUDLISZAK DZIEWANOWSKA A
     F-21068
PUTNAM, B *L-10998
    QUITTER V  *B-25370


                     R

    RAUSCHER J A  B-26095
    REHME, K A  C-09033, C-11089
    REMIREZR  'B-16718
    RIES E D  A-13841, F-13802
    RMMER L G  B-16480
    ROESNER G  *B-17889
    ROLLKH *B-19033
    ROMOVACEKJ  'B-21703
    ROSENDAHL F  *B-24594
    ROYTER V A  F-16377
    RUDLING B  B-25275
    RUMYANTSEVA Y S   B-16291
    RYABCHENKO A I  F-14539
    RZAYEV P B  *F-16377
                     S

    SAFIULLIN N S  *B-14568
    SAKABE, H  C-03035
    SCARINGELLI, F P  *C-00482, *C-09033,
         *C-11089
    SCHEIDEL, C F  *B-11250
    SCHON F  F-14506
    SCHWARTZ I  "J-21206
    SEMRAU K T  J-21308
    SHLIFER V A   A-13403, B-19370
    SIEDLEWSKIJ   *B-13880
    SILVERMAN L   B-24110
    SILVERMAN, L  *B-05567, B-07552
    SKRIVANEK J  *B-25768
    SMIRNOV V I   F-14626
    SMYSLOV N I *B-14386
    SNAJBERK, K  C-01387, D-05152
    SNOWBALL A F  *B-22055
    SNOWBALL, A F *A-04946
    SORDELLI, D  *B-01125
    SRBEK J  *B-17810
    SRYVALIN I T   F-14626
    STAROSEL SKII, Y I   B-08181
    STASTNY, E P  *B-00800
    STEINKE I *C-14735
    STOPPERKA K  *F-22154
    STOPPERKA, K  'B-02985
    STREICHER J S  *F-14845
    STRUSINSKY A  C-20595
    STUBER P J  B-25133
    SUCHKOV A B   'F-15325, *F-15416
    SYKES W  'B-25643
TAKAHASHI A  *C-21056
TAKEUCfflT *B-19592
TAMM O M  *B-16447
TAMURA Z  *B-20777
TANAKA T  B-19592
TAYLOR HD *C-19384
TEICHMAN T  C-15745
TESKE,  W  *B-11058
TEWORTE W M  *A-25178
THOMAS R S  C-15745
THOMPSON A P  'A-13850
TOYAMA, T  *L-05407
TRABER D G  B-16289, B-16290, B-20024,
     F-16292
TSUDO K  *B-19644
UBL, Z  "C-09983
UHI K  *C-14486
                 u
                 V
VARLAMOV, M L  *B-08181
VASIL EVA E M  B-16447
VOLKOVA E I   B-16480
VOSSELLER, W P  B-05079


                 W

WAKEFIELD, R E  B-09559
WATANABE H   1-24160
WEISSENBERGER G  *A-23972
WESOLOWSKIJ   F-21068
WILSON, H N *C-09369
WINKLER, K  B-09126
WOHLERS, H C  *N-04845
WOLFGANG, H  *B-11906
WOOLLAM J P V *B-19469
WRIGHT G A  'L-25520
WYSZYNSKAH  *C-20595
YASHKE YE V *B-24256
YESELEV I M  *B-16289, *B-16290,
     *B-20024
YORK 0 H  *B-24833
                                          ZANON, D  B-01125
                                          ZIRNGIBL H  F-14506
                                          ZWILLINGJP  *B-11629

-------
                                           SUBJECT  INDEX
                                                                                                                         51
ABATEMENT  A-21221, B-11906, L-25520
ABSORPTION  A-02235, A-13403, A-18305,
     A-25178, B-00587, B-01125, B-03945,
     B-07535, B-07J52, B-08181, B-09126,
     B-09913, B-11235, B-13667, B-14568,
     B-16718, B-17889, B-19370, B-19383,
     B-19593, B-22055, B-24110, B-24833,
     B-25133, C-09633, E-21791, F-00530,
     F-10907, F-13940, J-17203, L-24033
ABSORPTION  (GENERAL)  A-12751,
     A-12823, A-23972, A-25605, B-07535,
     B-09913, B-11250, B-11629, B-11906,
     B-13206, B-13672, B-14030, B-15739,
     B-15879, B-15991, B-17053, B-17810,
     B-17889, B-19228, B-19469, B-19592,
     B-19606, B-19644, B-19856, B-19886,
     B-20670, B-21824, B-24103, B-24451,
     B-24594, B-24628, B-24673, B-24695,
     B-25275, B-25468, B-25742, B-25768,
     F-13652,  1-24160, J-17203, L-24033
ACETONE  C-22645
ACETYLENES  B-03129, B-07925
ACID SMUTS  A-23044, B-21824,  B-24833,
     C-24970
ACIDS   A-02235, A-04946, A-10749,
     A-12633, A-12751, A-12823, A-13403,
     A-13596, A-13841, A-13850, A-15517,
     A-18305, A-21221, A-23044, A-25178,
     A-25605, B-00587, B-00800, B-01125,
     B-02355,  B-02985, B-03129, B-03945,
     B-04067,  B-05079, B-05514, B-05567,
     B-06247,  B-06282, B-07535, B-07552,
     B-07925,  B-08181, B-09126, B-09559,
     B-09913,  B-11058, B-11146, B-11235,
     B-11238,  B-11250, B-11629, B-11906,
     B-13206,  B-13337, B-13667, B-13672,
     B-13728,  B-13806, B-13880, B-14030,
     B-14386,  B-14533, B-14568, B-15739,
     B-15846,  B-15879, B-15991, B-16289,
     B-16290,  B-16291, B-16447, B-16480,
     B-16718,  B-17053, B-17810, B-17887,
     B-17889,  B-19033, B-19228, B-19370,
     B-19383,  B-19486, B-19592, B-19593,
     B-19594,  B-19595, B-19606, B-19644,
     B-19682,  B-19856, B-19943, B-20024,
     B-20248,  B-20416, B-20670, B-20777,
     B-21309,  B-21703, B-21824, B-22055,
     B-22182,  B-22943, B-23048, B-23070,
     B-23264,  B-23556, B-23939, B-24103,
     B-24110,  B-24246, B-24256, B-24451,
     B-24594,  B-24628, B-24673, B-24695,
     B-24833,  B-25133, B-25275, B-25370,
     B-25468,  B-25491, B-25643, B-25717,
     B-25742,  B-25768, B-26095, B-26254,
     C-00040, C-00381, C-00482, C-01387,
     C-01819,  C-03035, C-03852, C-09033,
     C-09295,  C-09369, C-09633, C-09983,
     C-11089,  C-11140, C-12596, C-14486,
     C-14735, C-15745, C-19384, C-20595,
     C-21056,  C-21415, C-22645, C-23771,
     C-24970,  C-25445, C-25851, D-05152,
     D-11492,  E-I0751, E-21791. F-00530,
     F-04626, F-10907, F-13652, F-13802,
     F-13875, F-13940, F-14249, F-14506,
      F-14625, F-14626, F-14641, F-14653,
      F-14845, F-14871, F-15325, F-15416,
      F-16292, F-16377, F-20274, F-21068,
      F-22098, F-22154, G-11379, G-16774,
      G-17623, G-22594, G-23930, 1-20820,
      1-24160, J-11791, J-17203, J-21206,
      J-21308, J-22397, K-06349, K-19750,
      L-05407, L-10998, L-11242, L-24033,
      L-25520, N-04845
ACROLEIN  C-09369
ACUTE  1-20820
ADMINISTRATION  A-04946, B-03129,
      B-20248, C-01819, L-05407
ADSORPTION  A-13403, B-01125, B-13880,
      B-14533, B-15846, B-19593, B-22182,
      C-03852, F-13940, J-21206
ADSORPTION (GENERAL) B-14660,
      B-20777, B-21824, B-22182, F-13652
AEROSOL GENERATORS  C-00482
AEROSOLS  B-05079, B-05567, B-06282,
      B-14568, B-24110, C-00040, C-00381,
      C-00482, C-01819, C-09033, C-09633,
      C-09983, C-11089, C-22645, C-25445,
      E-21791, F-00530, G-11379, G-16774,
      G-17623, G-22594, N-04845
AFRICA  F-00530, L-11242
AFTERBURNERS  B-07535, B-07925,
      B-23070, J-21206
AIR POLLUTION EPISODES  F-00530,
      G-16774
AIR QUALITY CRITERIA  G-16774
AIR QUALITY MEASUREMENT
      PROGRAMS C-01819
AIR QUALITY MEASUREMENTS
      A-04946, C-00040, C-01819, C-20595,
      D-05152, D-11492, F-00530, G-16774,
      L-05407, N-04845
AIR QUALITY STANDARDS  B-03129,
      D-11492, G-11379, K-06349, K-19750
ALCOHOLS  B-24594, C-09369, C-09983,
      C-22645
ALDEHYDES C-09369, C-09983, E-21791
ALIPHATIC HYDROCARBONS  B-03129,
      B-07925, C-09369, C-12596
ALKALINE ADDITIVES  A-12751,
      A-12823, A-13403, A-23044, A-25605,
      B-14660, B-20248, B-24594, B-25491,
      F-00530, L-24033
ALKALIZED ALUMINA (ADSORPTION)
      F-00530
ALLERGIES F-00530
ALTITUDE  E-10751, E-21791, N-04845
ALUMINUM B-03129, B-07925, B-20248,
      B-25643
ALUMINUM COMPOUNDS  A-25178,
      B-07925, B-20248, B-23070, B-24110,
      F-16377
ALUMINUM OXIDES B-20248, B-23070,
      F-14539
ALVEOLI  F-00530
AMIDES  B-24594
AMINES  B-01125, B-15879, B-15991
AMMONIA  A-18305, B-13667, B-15739,
      B-19370, B-24594, C-09369, C-09983,
      C-24970
AMMONIUM CHLORIDE  C-23771
AMMONIUM COMPOUNDS  A-04946,
      A-18305, B-07552, B-13667, B-15739,
      B-17889, B-19370, B-19383, B-19592,
      B-19606, B-24110, B-24594, C-09033,
      C-09369, C-09983, C-23771, C-24970,
      1-24160, J-21308
ANALYTICAL METHODS B-02355,
      B-19594, B-19595, B-20248, C-00040,
      C-00381, C-00482, C-03852, C-09033,
      C-09295, C-09369, C-09633, C-09983,
      C-11089, C-11140, C-12596, C-14486,
      C-14735, C-15745, C-17700, C-19384,
      C-20595, C-21415, C-24970, C-25445,
      C-25851, D-05152, F-00530, F-16292,
      G-11379, 1-20820, K-06349
ANIMALS  C-00381, F-00530, G-11379,
      G-16774, G-17623, G-23930, 1-20820
ANNUAL  K-19750
AROMATIC HYDROCARBONS  B-07925,
      B-11058, B-15879, B-15991, C-09983,
      C-20595
ARSENIC COMPOUNDS  B-11238, C-09983
ASBESTOS  B-26254
ASHES   B-07535, B-07925
ASIA B-15846, B-19486, B-19592, B-19644,
      B-20416, B-20777, B-23264, B-24673,
      B-25742, C-03035, C-14486, C-21056,
      F-00530, 1-24160, L-05407, L-11242
ASTHMA F-00530
ATMOSPHERIC MOVEMENTS  A-04946,
      C-01387, D-11492, E-10751
AUTOMATIC METHODS  C-01819,
      C-25445
AUTOMOBILES  B-07535
AUTOMOTIVE EMISSIONS  B-07535,
      C-00381, C-09369, C-09633, F-00530
AZO DYE  C-09295
                  B
BAG FILTERS  A-10749, A-25605, B-07925,
     B-23556
BARIUM COMPOUNDS  B-23070, C-11140,
     F-16377
BASIC  OXYGEN FURNACES  B-07925,
     B-26254
BENZENES  B-07925, C-20595
BERYLLIOSIS  B-00587, B-00800, B-02355,
     C-00381, C-00482,  C-01387, C-01819,
     C-03035, C-03852
BERYLLIUM  K-06349
BERYLLIUM COMPOUNDS  K-06349,
     K-19750
BIOCLIMATOLOGY  F-00530
BIOMEDICAL  TECHNIQUES AND
     MEASUREMENT   B-04067, F-00530,
     G-11379
BLAST FURNACES  A-10749, B-23939,
     B-25643
BLOOD CELLS  G-11379
BODY  CONSTITUENTS AND PARTS
     F-00530,  G-11379,  L-05407
BODY  FLUIDS  G-11379
BODY  PROCESSES AND FUNCTIONS
     F-00530, G-11379

-------
52
SULRJRIC ACID MANUFACTURING
BOILERS  B-07535, B-07925, B-19469,
      B-19886, B-20777, B-25468, B-25643,
      F-20274
BORON COMPOUNDS  C-09369
BREATHING  G-11379
BRONCHITIS  F-00530, G-11379
BRONCHOCONSTRICTION  G-16774
BUBBLE TOWERS  B-07925, B-15991
BUDGETS  B-20248
BUILDINGS  E-10751
BUTANES  C-09369
BY-PRODUCT RECOVERY  A-12751,
      A-12823, A-13850, A-18305, A-23972,
      A-25178, B-09559, B-09913, B-11146,
      B-11238, B-11250, B-11629, B-11906,
      B-13337, B-13672, B-13728, B-14030,
      B-14533, B-15739, B-17053, B-17810,
      B-17887, B-19370, B-19383, B-19469,
      B-19592, B-19595, B-19886, B-20416,
      B-20670, B-20777, B-21309, B-22055,
      B-23048, B-23939, B-24103, B-24246,
      B-24451, B-24594, B-24628, B-24673,
      B-25133, B-25275, B-25491, F-14871,
      1-24160, J-11791, J-17203, J-21206,
      J-21308, J-22397, L-10998, L-11242,
      L-24033
CADMIUM COMPOUNDS  A-13596
CALCIUM COMPOUNDS  B-11058,
     B-19644, B-23048, B-25742, C-24970,
     F-14506
CALCIUM SULFATES  B-19644, B-23048,
     F-14506
CALIBRATION METHODS  C-00381,
     C-00482, C-03852, C-25851
CALIFORNIA   B-07535, C-0%33, D-05152
CANADA  A-04946, B-19606, B-22055,
     C-00381, C-00482, C-01819, C-03035,
     C-15745, C-22645, C-25445, E-21791,
     F-00530, F-14249, L-11242
CARBIDES  B-11058
CARBON DIOXIDE B-11235, C-09369,
     C-24970, C-25851
CARBON DISULFIDE  B-07925, B-23070,
     C-09983, C-20595
CARBON MONOXIDE  B-24594, C-09369,
     C-09983, C-12596, J-21206,  K-06349,
     K-19750
CARBONATES B-15879, B-20248,  B-25768
CARBONYLS  C-09369
CARCINOGENS B-01125,  C-00381,
     C-01387, C-01819, C-03852, F-00530
CASCADE SAMPLERS  C-03035, C-09633,
     C-23771
CATALYSIS  A-13850, A-23972,  B-01125,
     B-09126, B-16289, B-16290, B-16291,
     B-16480, B-16718, B-17887, B-19486,
     B-20024, B-22055, B-23070, C-11089,
     F-04626, F-13802, F-14249,  F-14526,
     F-14539, F-14845, F-16292,  F-16377,
     F-21068
CATALYSTS  A-13850, A-23972, B-09126,
     B-16289, B-16290, B-16291, B-17887,
     B-20024, B-23070, F-04626, F-14249,
     F-14845, F-21068
CATALYTIC ACTIVITY B-16480,  B-19486,
     B-20024, C-11089, F-04626, F-13802,
     F-14526, F-14539, F-16292,  F-16377,
     F-21068
CATALYTIC AFTERBURNERS  B-07535,
     B-07925, B-23070
CATALYTIC OXIDATION  A-13841,
     B-01125, B-09913, B-11629, B-13206,
          B-13672, B-13806, B-13880, B-14030,
          B-16289, B-16290, B-16291, B-16480,
          B-17887, B-19228, B-19486, B-19886,
          B-19943, B-20024, B-20670, B-24103,
          B-24628, C-09033, F-13652, F-13802,
          F-13940, F-14249, F-14526, F-14538,
          F-14539, F-14625, F-14641, F-14653,
          F-16292, F-16377, F-20274, F-21068,
          J-21206
    CELLS  F-00530, G-11379, G-23930
    CEMENTS  A-21221, B-07535, B-25643,
          F-14506, J-17203
    CENTRIFUGAL SEPARATORS  A-13596,
          B-04067, B-17889, C-23771, J-21206
    CERAMICS B-07925
    CHAMBER PROCESSING  A-02235,
          B-07925, B-11906, B-14533, B-14568,
          B-25643, C-00040, C-17700
    CHARCOAL B-11250, B-13880, B-14533,
          B-15846, B-19592, F-00530, F-13652,
          F-13940
    CHEMICAL COMPOSITION  A-04946,
          C-00040, C-20595
    CHEMICAL METHODS  C-00040,  C-09033,
          C-09633, C-09983, C-12596, C-14735,
          C-15745, C-17700, C-20595, C-21415,
          C-24970, D-05152, G-11379
    CHEMICAL PROCESSING  A-02235,
          A-04946, A-10749, A-12633, A-13403,
          A-13841, A-13850, A-15517, A-18305,
          A-21221, A-23044, A-23972, B-00587,
          B-00800, B-01125, B-02355, B-02985,
          B-03129, B-03945, B-04067, B-05079,
          B-06247, B-06282, B-07535, B-07925,
          B-08181, B-09126, B-11058, B-11235,
          B-11238, B-11250, B-11906, B-13206,
          B-13667, B-13672, B-13728, B-13806,
          B-14030, B-14386, B-14533, B-14568,
          B-14660, B-15846, B-16289, B-16290,
          B-16291, B-16447, B-16718, B-17053,
          B-17810, B-19033, B-19370, B-19383,
          B-19469, B-19486, B-19593, B-19595,
          B-19644, B-19682, B-19856, B-19886,
          B-20248, B-20416, B-20670, B-21824,
          B-22055, B-22943, B-23556, B-23939,
          B-24246, B-24673, B-24695, B-24833,
          B-25133, B-25370, B-25468, B-25643,
          B-26254, C-00040, C-01387, C-03852,
          C-09295, C-17700, C-23771, D-05152,
          D-11492, E-10751, F-13802, F-14249,
          F-14506, F-14526, F-14538, F-14539,
          F-14641, F-14653, F-22098, 1-20820,
          1-24160, J-11791, J-17203, J-21206,
          L-05407, L-10998, L-11242, L-24033,
          L-25520
    CHEMICAL REACTIONS  A-02235,
          A-10749, A-12751, A-12823, B-01125,
          B-09126, B-11906, B-15739, B-19886,
          B-23556, B-24673, C-09033, C-0%33,
          E-21791, F-04626, F-10907, F-13875,
          F-14506, F-15325, F-15416
    CHLORIDES  B-11238, C-09369, L-24033
    CHLORINE A-18305, B-01125, B-03129,
          C-09369, C-09983, C-24970, L-24033
    CHLORINE COMPOUNDS  B-00587,
          B-11238, B-21703, C-09369, C-20595,
          L-24033
    CHROMATOGRAPHY  B-19595, C-12596
    CHROMIUM COMPOUNDS  F-14539
    CHROMIUM OXIDES F-14526
    CHRONIC  F-00530, G-11379, 1-20820,
          N-04845
    CILIA  F-00530
    CINDERS  B-06282
    CIRCULATORY SYSTEM  G-11379
    CLEAN AIR ACT  B-07925, F-00530
COAL A-12633, A-23044, B-07535,
      B-07925, B-11250, F-00530, 1-20820,
      J-11791, L-10998
COAL PREPARATION  A-15517, B-15846,
      B-20248, J-11791, L-10998
COBALT COMPOUNDS  F-14626
COFFEE-MAKING  B-26254
COKE A-23044, B-07925, B-22055,
      B-22182, F-00530
COLLECTORS  A-13596, A-25605, B-00587,
      B-00800, B-04067, B-17889, B-19886,
      B-20777, B-22943, C-09033, C-23771,
      J-21206, L-05407
COLORIMETRY  C-00040, C-00381,
      C-03852, C-09033, C-09295, C-09983,
      C-11089, C-14735, C-20595, C-25445,
      C-25851, D-05152, 1-20820
COMBUSTION  A-23044, B-09126
COMBUSTION AIR A-10749, B-23939
COMBUSTION GASES  A-04946, A-12751,
      A-12823, A-15517, A-23044, A-23972,
      A-25605, B-00800, B-01125, B-03945,
      B-05567, B-07925, B-11058, B-11250,
      B-11629, B-11906, B-13337, B-13672,
      B-14568, B-14660, B-15739, B-15879,
      B-15991, B-16718, B-17053, B-19033,
      B-19228, B-19370, B-19469, B-19592,
      B-19606, B-19644, B-19856, B-19886,
      B-19943, B-20777, B-21309, B-21824,
      B-22943, B-23070, B-23264, B-23939,
      B-24103, B-24110, B-24246, B-24451,
      B-24594, B-24628, B-24673, B-24833,
      B-25133, B-25275, B-25491, B-25742,
      B-25768, C-11140, C-14735, C-17700,
      E-10751, F-20274, 1-20820, J-21206,
      J-22397, L-10998, L-24033, N-04845
COMBUSTION PRODUCTS A-04946,
      A-12751, A-12823, A-15517, A-23044,
      A-23972, A-25605, B-00800, B-01125,
      B-03945, B-05567, B-06282, B-07535,
      B-07925, B-11058, B-11250, B-11629,
      B-11906, B-13337, B-13672, B-14568,
      B-14660, B-15739, B-15879, B-15991,
      B-16718, B-17053, B-19033, B-19228,
      B-19370, B-19469, B-19592, B-19606,
      B-19644, B-19856, B-19886, B-19943,
      B-20777, B-21309, B-21824, B-22943,
      B-23070, B-23264, B-23939, B-24103,
      B-24110, B-24246, B-24451, B-24594,
      B-24628, B-24673, B-24833, B-25133,
      B-25275, B-25491, B-25742, B-25768,
      C-11140, C-14735, C-17700, E-10751,
      F-20274, 1-20820, J-21206, J-22397,
      L-10998, L-24033, N-04845
COMMERCIAL AREAS K-06349
COMMERCIAL EQUIPMENT  B-01125
COMMERCIAL FIRMS  L-24033
COMPRESSED GASES  B-00587
COMPUTER PROGRAMS   F-22098
CONDENSATION  B-19606, B-19682,
      B-24110, C-19384
CONDENSATION (ATMOSPHERIC)
      D-05152
CONSTRUCTION MATERIALS A-21221,
      B-07535, B-25643, F-14506, J-17203
CONTACT PROCESSING   A-02235,
      A-10749, A-12633, A-13841, A-18305,
      A-23972, B-07925, B-09126, B-11058,
      B-11906, B-13667, B-13728, B-13806,
      B-14386, B-14660, B-16289, B-16290,
      B-16291, B-16718, B-19469, B-19486,
      B-19682, B-19856, B-19886, B-21824,
      B-22055, B-24695, B-25133, B-25643,
      C-00040, C-09295, F-14249, F-14526,
      F-14538, F-14539, F-14653, L-24033
CONTINUOUS AIR MONITORING
      PROGRAM (CAMP)   C-01819

-------
                                                   SUBJECT INDEX
                                                                               53
CONTINUOUS MONITORING  B-07925,
      B-20248, C-01819, C-125%, C-21056,
      C-21415, C-25851, D-05152, G-11379
CONTROL EQUIPMENT  A-02235,
      A-04946, A-10749, A-12751, A-12823,
      A-I3403, A-13596, A-23044, A-25605,
      B-00587, B-00800, B-01125, B-02355,
      B-02985, B-03129, B-03945, B-04067,
      B-05079, B-05514, B-05567, B-06247,
      B-07535, B-07552, B-07925, B-08181,
      B-09559, B-11058, B-11235, B-11238,
      B-11629, B-13337, B-13667, B-14568,
      B-15879, B-15991, B-17889, B-19033,
      B-19383, B-19469, B-19644, B-1%82,
      B-19886, B-20248, B-20777, B-22055,
      B-22943, B-23070, B-23264, B-23556,
      B-23939, B-24110, B-24256, B-24594,
      B-24673, B-24695, B-24833, B-25370,
      B-25643, B-25717, B-25768, B-26095,
      B-26254, C-00040, C-01387, C-09033,
      C-11089, C-22645, C-23771, C-25851,
      D-05152, F-00530, J-17203, J-21206,
      L-05407, L-24033
CONTROL METHODS  A-02235, A-04946,
      A-10749, A-12751, A-12823, A-13403,
      A-13841, A-13850, A-15517, A-18305,
      A-23044, A-23972, A-25178, A-25605,
      B-00587, B-00800, B-01125, B-02355,
      B-02985, B-03129, B-03945, B-04067,
      B-06282, B-07535, B-07552, B-07925,
      B-08181, B-09126, B-09559, B-09913,
      B-11058, B-11146, B-11235, B-11238,
      B-11250, B-11629, B-11906, B-13206,
      B-13337, B-13667, B-13672, B-13728,
      B-13806, B-13880, B-14030, B-14386,
      B-14533, B-14568, B-14660, B-15739,
      B-15846, B-15879, B-15991, B-16289,
      B-16290, B-16291, B-16447, B-16480,
      B-16718, B-17053, B-17810, B-17887,
      B-17889, B-19033, B-19228, B-19370,
      B-19383, B-19469, B-19486, B-19592,
      B-19593, B-19595, B-19606, B-19644,
      B-19856, B-19886, B-19943, B-20024,
      B-20248, B-20416, B-20670, B-20777,
      B-21309, B-21703, B-21824, B-22055,
      B-22182, B-22943, B-23048, B-23070,
      B-23264, B-23939, B-24103, B-24110,
      B-24246, B-24451, B-24594, B-24628,
      B-24673, B-24695, B-24833, B-25133,
      B-25275, B-25468, B-25491, B-25643,
      B-25717, B-25742, B-25768, B-26254,
      C-03852, C-09033, C-09633, E-21791,
      F-00530, F-10907, F-13652, F-13802,
      F-13940, F-14249, F-14526, F-14538,
      F-14539, F-14625, F-14641, F-14653,
      F-14871, F-16292, F-16377, F-20274,
      F-21068, 1-24160, J-11791, J-17203,
      J-21206, J-21308, J-22397, L-05407,
      L-10998, L-11242, L-24033
CONTROL PROGRAMS  A-04946,  B-03129,
      B-20248, L-05407
CONTROLLED ATMOSPHERES  C-00381
COOLING  B-19606, B-22055
COPPER  B-07925, B-11146, B-11906,
      B-21309, B-23939, B-25275, C-09033,
      C-11089
COPPER COMPOUNDS  A-12751, A-12823,
      B-07925, C-09033, C-11089, F-14626
CORONA   B-05514, B-23264
CORROSION   B-00800, B-02985, B-03945,
      B-22055, C-03035, 1-20820, I-24I60,
      N-04845
COSTS  A-12751, A-12823, A-13850,
      A-15517, A-18305, A-2122I, A-25178,
      B-01125, B-05079, B-05514, B-07552,
      B-11238, B-11250, B-16718, B-17053,
      B-21309, B-21824, B-23048, B-23556,
      B-25133, F-14845, J-11791, J-17203,
      J-21206, J-21308, L-10998
CRACKING  1-20820
CRITERIA  A-12823, G-16774
CRYSTAL STRUCTURE  F-14653
CUPOLAS  B-07925
CYANIDES   C-09369
CZECHOSLOVAKIA  B-13206, B-17810,
      B-21703, B-25491, B-25768, C-00381,
      C-00482, C-01387, C-03852, C-09983,
      F-00530


                   D

DATA ANALYSIS  C-01387
DATA HANDLING SYSTEMS C-01387,
      F-22098
DECOMPOSITION   B-15739, B-23556,
      C-09033, F-14506, F-15325, F-15416
DELAWARE  B-02985
DENSITY  B-24256, B-24673, C-21056
DESIGN CRITERIA  A-10749, A-25605,
      B-00800, B-07925, B-11146, B-11238,
      B-13337, B-17053, B-17887, B-19606,
      B-19644, B-20777, B-21703, B-21824,
      B-24695, B-25370, B-25643, B-25717,
      B-26095, C-25851, F-14249
DESULFURIZATION OF FUELS A-15517,
      A-23044, B-15846, B-20248, B-21703,
      F-00530, J-11791, L-10998
DIFFUSION  C-15745, E-10751
DIFFUSION MODELS  E-10751
DIGESTIVE SYSTEM G-11379, G-23930
DIOLEFINS  B-07925
DISCOLORATION  1-20820
DISPERSION  A-15517, B-01125, C-15745,
      D-11492, E-10751, F-00530
DISSOCIATION  E-21791, F-13875, F-14506
DIURNAL  G-11379, K-19750
DOMESTIC HEATING  B-07535, F-00530
DONORA  F-00530
DROPLETS   B-24110, C-00381, C-09633
DRYING  B-25491
DUST FALL  A-04946, F-00530, L-05407
DUSTS  B-04067, B-05079, B-06282,
      B-07535, B-07925, B-11058, B-11906,
      B-17889, B-20777, B-22943, B-24110,
      B-25643, B-26254, C-09983, C-20595,
      C-23771, J-17203, L-05407
ECONOMIC LOSSES  J-11791, J-17203,
      J-22397
ELECTRIC CHARGE  B-05514, B-25468
ELECTRIC FURNACES  B-07925
ELECTRIC POWER PRODUCTION
      A-15517, A-21221, A-23044, B-07925,
      B-11238, B-11250, B-11906, B-14660,
      B-24673, E-10751, J-17203, L-10998,
      L-11242, L-24033
ELECTRICAL MEASUREMENT DEVICES
      C-00381, G-22594
ELECTRICAL PROPERTIES  B-05514,
      B-23264, B-25468, B-25643
ELECTROCHEMICAL METHODS
      C-09983, C-12596, C-14735, C-15745,
      C-21415, G-11379
ELECTROCONDUCnvrTY ANALYZERS
      C-01819, C-125%, C-21056, C-25851,
      D-05152
ELECTROLYSIS  B-25491
ELECTROSTATIC PRECIPITATORS
      A-10749, A-13596, A-25605, B-00587,
      B-00800, B-02985, B-05514, B-07535,
      B-07925, B-09559, B-11235, B-11238,
      B-17889, B-19033, B-19886, B-20248,
      B-22943, B-23264, B-23939, B-24256,
      B-25370, B-25643, C-00040, C-01387,
      D-05152, J-21206, L-24033
EMISSION STANDARDS  B-03129,
      B-16718, L-25520
EMISSIVTTY  F-00530
EMPHYSEMA  G-11379
ENGINE EXHAUSTS  B-07535, C-00381,
      C-09369, C-09633, F-00530
ENZYMES  F-00530, G-11379
EPIDEMIOLOGY  F-00530
ESTERS   B-05079, B-25742
ETHYLENE  B-07925
EUROPE  A-02235, A-13403, A-18305,
      A-23972, A-25178, B-00587, B-00800,
      B-02985, B-03129, B-03945, B-04067,
      B-07535, B-07925, B-08181, B-09126,
      B-09913, B-11058, B-11629, B-11906,
      B-13206, B-13337, B-13728, B-13880,
      B-14030, B-14386, B-14568, B-14660,
      B-15739, B-16289, B-16290, B-16291,
      B-16447, B-16480, B-17810, B-17887,
      B-17889, B-19228, B-19469, B-1%82,
      B-19856, B-19943, B-20024, B-20670,
      B-21703, B-22182, B-23070, B-23939,
      B-24256, B-24451, B-24594, B-24628,
      B-24695, B-25275, B-25370, B-25468,
      B-25491, B-25643, B-25768, C-00381,
      C-00482, C-01387, C-03852, C-09295,
      C-09983, C-14735, C-17700, C-19384,
      C-20595, C-21415, C-24970, C-25851,
      E-10751, F-00530, F-04626, F-10907,
      F-13652, F-13875, F-13940, F-14526,
      F-14538, F-14539, F-14625, F-14626,
      F-14641, F-14653, F-14871, F-15325,
      F-15416, F-16292, F-16377, F-21068,
      F-22098, F-22154, G-11379, G-17623,
      G-22594, J-17203, L-11242, L-24033
EXHAUST SYSTEMS  A-135%, B-04067,
      B-22055
EXPERIMENTAL EQUIPMENT  B-05079
EXPERIMENTAL METHODS  C-01387,
      C-09983
EXPOSURE CHAMBERS C-00381,
      G-16774
EYE IRRITATION  E-21791, 1-20820
EYES  1-20820
FALLOUT  C-01387
FANS (BLOWERS) A-13596, B-04067,
     B-22055
FARMS  F-00530, K-06349
FEASIBILITY STUDIES  A-21221, L-10998
FEDERAL GOVERNMENTS  B-07925
FERTILIZER MANUFACTURING
     A-21221, B-15739, F-14871, J-21206
FERTILIZING  A-04946,  B-03129, B-11058,
     L-11242
FIELD TESTS  C-03852
FILTER FABRICS  B-05567, B-20248,
     B-24110, B-24256, B-24695, B-25717,
     B-26095, B-26254, C-09033, C-11089,
     C-22645
FILTERS  A-10749, A-13403, A-25605,
     B-05079, B-05567, B-06247, B-07552,
     B-07925, B-13667, B-14568, B-19682,
     B-20248, B-22943, B-23556, B-24110,
     B-24256, B-24695, B-25717, B-26095,
     B-26254, C-09033, C-11089, C-22645,
     C-23771, D-05152, J-17203, J-21206
FIRING METHODS  A-10749, B-07925,
     B-23939

-------
 54
SULFURIC ACID MANUFACTURING
FLAME AFTERBURNERS  B-07925
FLAME IONIZATION DETECTOR
      C-12596
FLARES  B-07925
FLOW RATES  A-12751, A-25605, B-00587,
      B-05079, B-05514, B-08181, B-23070,
      B-23264, B-24110, B-24256, B-25768,
      C-00381, C-00482
FLUID FLOW  A-12751,  A-25605, B-00587,
      B-05079, B-05514, B-08181, B-23070,
      B-23264, B-24110, B-24256, B-25768,
      C-00381, C-00482
FLUORESCENCE C-11140, C-12596
FLUORIDES  B-01125, B-07552, B-11058,
      B-11238, B-26254, K-06349
FLUORINE  A-18305, B-03129, C-09369,
      C-09983, C-24970, K-06349, L-24033
FLUORINE COMPOUNDS  A-25178,
      B-01125, B-07552, B-07925, B-11058,
      B-11238, B-26254, C-09369, C-20595,
      K-06349
FLY ASH  B-05567, B-07552, B-07925,
      B-19606, B-25643, F-00530, G-23930
FOG  D-05152
FOOD AND FEED OPERATIONS B-26254
FORESTS  F-00530
FORMALDEHYDES  C-09369, C-09983
FORMIC ACID  B-25742
FRANCE   B-09913, B-11629, B-13728,
      B-14030, C-21415
FREE RADICALS E-21791
FUEL GASES  B-07925, B-11629, B-19886
FUEL OILS  A-12633, A-23044,  B-07925,
      B-11250, F-00530
FUELS  A-12633, A-15517, A-23044,
      B-07535, B-07925, B-11250, B-11629,
      B-19886, B-22055, B-22182, F-00530,
      1-20820, J-11791, L-10998
FUMES  A-25605, B-01125, B-03129,
      B-07552, B-07925, B-19383, B-21824
FUMIGATION  F-00530
FURNACES  A-10749, A-23044,  B-05567,
      B-06282, B-07535, B-07925, B-19606,
      B-19886, B-23939, B-25643, B-26254
                   G
GAS CHROMATOGRAPHY  C-12596
GAS SAMPLING  B-20248, C-24970
GASES  A-04946, B-00587, B-00800,
      B-03945, B-05514, B-09913, B-11238,
      B-15879, B-15991, B-19682, B-22182,
      B-24110, B-25768, C-09633
GASIFICATION (SYNTHESIS)  B-15846
GASOLINES  F-00530
GERMANY  A-23972, A-25178, B-02985,
      B-07535, B-09126, B-11058, B-11906,
      B-13337, B-14660, B-17889, B-19228,
      B-20670, B-22182, B-24594, B-24628,
      B-25370, C-03852, C-14735, C-24970,
      F-00530, F-10907, F-22154, J-17203
GLASS FABRICS  B-24110, B-24256,
      B-25717, B-26095, B-26254, C-09033,
      C-11089, C-22645
GOVERNMENTS  B-07925, K-06349,
      K-19750, L-24033
GRAVITY SETTLING  B-25717
GREAT BRITAIN  B-07535, B-07925,
      B-13337, B-19469, B-24695, B-25643,
      C-19384, C-25851, E-10751, F-14871,
      L-24033
GROUND LEVEL  E-10751
GUINEA PIGS  G-17623, G-23930, 1-20820
                       H

    HALOGEN GASES A-18305, B-01125,
          B-03129, C-09369, C-09633, C-09983,
          C-24970, K-06349, L-24033
    HEALTH IMPAIRMENT  B-04067, F-00530,
          L-05407, N-04845
    HEALTH STATISTICS F-00530
    HEART  G-11379
    HEAT CAPACITY  F-00530
    HEAT TRANSFER  B-19606, B-22055,
          B-24103, B-24628, C-09033
    HEMATOLOGY  F-00530
    HI-VOL SAMPLERS  C-01819, C-09033,
          C-11089, C-15745
    HOURLY  K-19750
    HUMANS  F-00530, G-16774, G-22594,
          1-20820
    HUMIDITY  C-00482, C-09633, D-05152,
          D-11492, E-21791, G-16774
    HYDROCARBONS  B-00587, B-03129,
          B-07925, B-11058, B-11235, B-15879,
          B-15991, C-09369, C-09983, C-12596,
          C-20595, E-21791, J-21206
    HYDROCHLORIC ACID  A-18305, B-07552,
          B-11058, B-22943, B-26254, C-03035,
          C-14486, C-24970, F-20274, L-24033
    HYDROFLUORIC ACID  B-01125, B-05567,
          B-07552, B-11058, B-22943, B-24110,
          B-26254, C-24970, K-19750, L-24033
    HYDROGEN  C-00381, C-21415, C-25851
    HYDROGEN SULFIDE  B-00800, B-07925,
          B-11058, B-11629, B-14030, B-17889,
          B-19033, B-19886, B-22943, B-23048,
          B-23070, B-24594, B-26254, C-00040,
          C-03852, C-09369, C-09983, C-20595,
          1-20820, K-06349, K-19750, L-24033,
          N-04845
    HYDROXIDES  B-22182, B-25468, B-25491,
          C-24970
                        I
    IMPINGERS  B-22943, C-09033, C-25851,
          D-05152
    INCINERATION  B-09913, B-20248
    INDUSTRIAL AREAS  A-18305, C-01387,
          D-05152, D-11492, K-06349
    INDUSTRIAL EMISSION SOURCES
          A-02235, A-04946, A-10749, A-12633,
          A-12751, A-12823, A-13403, A-13596,
          A-13841, A-13850, A-15517, A-18305,
          A-21221, A-23044, A-23972, A-25178,
          A-25605, B-00587, B-00800, B-01125,
          B-02355, B-02985, B-03129, B-03945,
          B-04067, B-05079, B-05567, B-06247,
          B-06282, B-07535, B-07925, B-08181,
          B-09126, B-09559, B-09913, B-11058,
          B-11146, B-11235, B-11238, B-11250,
          B-11906, B-13206, B-13667, B-13672,
          B-13728, B-13806, B-14030, B-14386,
          B-14533, B-14568, B-14660, B-15739,
          B-15846, B-16289, B-16290, B-16291,
          B-16447, B-16718, B-17053, B-17810,
          B-19033, B-19370, B-19383, B-19469,
          B-19486, B-19593, B-19595, B-19644,
          B-19682, B-19856, B-19886, B-20248,
          B-20416, B-20670, B-21309, B-21824,
          B-22055, B-22943, B-23556, B-23939,
          B-24246, B-24451, B-24673, B-24695,
          B-24833, B-25133, B-25275, B-25370,
          B-25468, B-25643, B-26254, C-00040,
          C-01387, C-03852, C-09295, C-17700,
          C-23771, D-05152, D-11492, E-10751,
          F-00530, F-13802, F-14249, F-14506,
      F-14526, F-14538, F-14539, F-14641,
      F-14653, F-14871, F-22098, 1-20820,
      1-24160, J-11791, J-17203, J-21206,
      J-21308, L-05407, L-10998, L-11242,
      L-24033, L-25520, N-04845
INFRARED SPECTROMETRY  F-22154
INORGANIC ACIDS  A-02235, A-04946,
      A-10749, A-12633, A-12751, A-12823,
      A-13403, A-13596, A-13841, A-13850,
      A-15517, A-18305, A-21221, A-23044,
      A-25178, A-25605, B-00587, B-00800,
      B-01125, B-02355, B-02985, B-03129,
      B-03945, B-04067, B-05079, B-05514,
      B-05567, B-06247, B-06282, B-07535,
      B-07552, B-07925, B-08181, B-09126,
      B-09559, B-09913, B-11058, B-11146,
      B-11235, B-11238, B-11250, B-11629,
      B-11906, B-13206, B-13337, B-13667,
      B-13672, B-13728, B-13806, B-13880,
      B-14030, B-14386, B-14533, B-14568,
      B-15739, B-15846, B-15879, B-15991,
      B-16289, B-16290, B-16291, B-16447,
      B-16480, B-16718, B-17053, B-17810,
      B-17887, B-17889, B-19033, B-19228,
      B-19370, B-19383, B-19486, B-19592,
      B-19593, B-19594, B-19595, B-19606,
      B-19644, B-19682, B-19856, B-19943,
      B-20024, B-20248, B-20416, B-20670,
      B-20777, B-21309, B-21703, B-21824,
      B-22055, B-22182, B-22943, B-23048,
      B-23070, B-23264, B-23556, B-23939,
      B-24103, B-24110, B-24246, B-24256,
      B-24451, B-24594, B-24628, B-24673,
      B-24695, B-24833, B-25133, B-25275,
      B-25370, B-25468, B-25491, B-25643,
      B-25717, B-25742, B-25768, B-26095,
      B-26254, C-00040, C-00381, C-00482,
      C-01387, C-01819, C-03035, C-03852,
      C-09033, C-09295, C-09369, C-09633,
      C-09983, C-11089, C-11140, C-12596,
      C-14486, C-14735, C-15745, C-19384,
      C-20595, C-21056, C-21415, C-22645,
      C-23771, C-24970, C-25445, C-25851,
      D-05152, D-11492, E-10751, E-21791,
      F-00530, F-04626, F-10907, F-13652,
      F-13802, F-13875, F-13940, F-14249,
      F-14506, F-14625, F-14626, F-14641,
      F-14653, F-14845, F-14871, F-15325,
      F-15416, F-16292, F-16377, F-20274,
      F-21068, F-22098, F-22154, G-11379,
      G-16774, G-17623, G-22594, G-23930,
      1-20820, 1-24160, J-11791, J-17203,
      J-21206, J-21308, J-22397,  K-06349,
      K-19750, L-05407, L-10998, L-11242,
      L-24033, L-25520, N-04845
INSTRUMENTATION C-00381, C-00482,
      C-01819, C-09633, C-25851, D-05152,
      F-00530
INTERNAL COMBUSTION ENGINES
      B-07535
INTERNATIONAL F-00530
INVERSION  A-04946, B-07535, E-21791,
      F-00530
IODIDES  C-03852, C-09633
IODIMETRIC METHODS   C-00040,
      C-17700, C-20595
IODINE COMPOUNDS  C-03852, C-09633
IONIZATION  B-05514
IONS  C-09633
IRON  A-04946, B-05567,  B-07925, B-20248,
      C-03035
IRON COMPOUNDS  A-04946, B-04067,
      B-07925, B-20024, B-24594, F-14626
      F-15325, G-16774, J-11791, L-10998
IRON OXIDES  B-07552,  B-07925, B-16289
      B-16290, B-16291, B-20024, F-13875
      F-15325, F-16292

-------
                                                   SUBJECT INDEX
                                                                               55
 ITALY  B-17887
 JAPAN  B-15846, B-19486, B-19592,
      B-19644, B-20416, B-20777, B-23264,
      B-24673, B-25742, C-03035, C-14486,
      C-21056, F-00530, 1-24160, L-05407


                   K

 KEROSENE  F-00530
 KETONES  A-23972, C-09369, C-22645
 KILNS  B-06282, B-07535, B-07925
 KRAFT PULPING A-15517, B-03129,
      B-20248, B-25643, B-26254
 LABORATORY ANIMALS  C-00381,
      F-00530, G-11379, G-16774, G-17623,
      G-23930, 1-20820
 LABORATORY FACILITIES  C-09983
 LARYNX  F-00530
 LEAD  A-04946, A-10749, B-02985,
      B-11238, B-21309, B-25275, C-09983
 LEAD COMPOUNDS  A-04946, A-10749,
      A-12751, A-12823, B-11238, B-25370,
      C-09983, K-19750
 LEAVES  F-00530
 LEGAL ASPECTS  A-21221, A-25605,
      B-03129, B-07925, B-24833, F-00530,
      K-06349, K-19750, L-05407, L-24033,
      L-25520
 LEGISLATION  B-03129, B-07925, F-00530,
      K-06349, L-05407, L-24033, L-25520
 LEUKOCYTES  G-11379
 LIGHT RADIATION  B-07535, E-21791
 LIMESTONE  A-21221, B-19644
 LIQUIDS   B-05079, B-07552, B-11235,
      B-19856, B-20777, B-23264, B-23556,
      B-25717, C-01387, C-09633, D-05152,
      F-10907, F-13652, F-22154
 LITIGATION  A-25605
 LIVER  G-11379, G-23930
 LONDON  B-07535
 LOS ANGELES  B-07535, C-09633
 LOWER ATMOSPHERE  E-21791
 LUNGS  F-00530, G-11379, G-17623
 LYMPHOCYTES  G-11379


                  M

 MAGNESIUM COMPOUNDS  F-13875
 MAINTENANCE  B-25643
 MANGANESE COMPOUNDS  B-19943,
      B-24673, C-09983, F-04626, F-15325,
      G-16774
 MANGANESE DIOXIDE (JAPANESE)
      B-20416
 MANGANESE SULFATES  B-19943,
      F-04626
 MASS SPECTROMETRY  C-125%
 MATERIALS DETERIORATION  B-00800,
      B-02985, B-03945, B-22055, C-03035,
      1-20820, 1-24160,  N-04845
MATHEMATICAL ANALYSES A-13841,
      B-055I4, B-25768, E-10751, F-00530,
      F-14249
MATHEMATICAL MODELING  B-25768,
      E-10751
MAXIMUM ALLOWABLE
      CONCENTRATION  B-03129,
      D-11492, G-11379, K-06349, K-19750
MEASUREMENT METHODS  B-07925,
      B-20248, C-00381, C-01387, C-01819,
      C-03035, C-03852, C-09033, C-09633,
      C-09983, C-11140, C-12596, C-21056,
      C-21415, C-25445, C-25851, D-05152,
      F-00530, G-11379
MEETINGS   L-05407
MEMBRANE FILTERS  C-25445
MERCAPTANS  B-07925, B-26254
MERCURY  B-11238
MERCURY COMPOUNDS A-23972,
      B-11238, B-21703, C-09369, C-23771
METABOLISM  G-11379
METAL COMPOUNDS A-04946, A-10749,
      A-12751, A-12823, A-13596, A-18305,
      A-23972, A-25178, B-04067, B-05079,
      B-07925, B-09126, B-09559, B-11058,
      B-11238, B-15879, B-15991, B-16480,
      B-17810, B-19486, B-19644, B-19943,
      B-20024, B-20248, B-21703, B-22182,
      B-23048, B-23070, B-23264, B-24110,
      B-24594, B-24673, B-25370, B-25491,
      B-25742, C-03035, C-03852, C-09033,
      C-09369, C-09983, C-11089, C-11140,
      C-23771, C-24970, F-04626, F-10907,
      F-13875, F-14506, F-14538, F-14539,
      F-14626, F-14871, F-15325, F-16377,
      F-21068, G-16774, J-11791, K-06349,
      K-19750, L-10998
METAL FABRICATING AND FINISHING
      A-15517, B-07925, B-20248, B-25643,
      B-26254
METALS  A-04946, A-10749, A-13841,
      A-13850, B-02985, B-03129, B-05567,
      B-07925, B-09559, B-11146, B-11238,
      B-11906, B-20248, B-21309, B-23939,
      B-25275, B-25643, C-03035, C-09033,
      C-09983, C-11089, F-13802, F-14538,
      F-14845, K-06349
METEOROLOGY A-04946, B-07535,
      C-00482, C-01387, C-09369, C-09633,
      D-05152, D-11492, E-10751, E-21791,
      F-00530, G-16774, N-04845
METHANES  C-12596
MICE  1-20820
MICROSCOPY  C-03035, C-09633
MIDDLE ATMOSPHERE  N-04845
MINERAL PROCESSING  A-04946,
      A-13596, A-21221, B-04067, B-07925,
      B-16447, B-25643, B-26254, C-03852,
      F-00530, J-17203
MINERAL PRODUCTS A-21221, B-07552,
      B-19644, B-23048, B-26254
MINING A-04946, B-26254
MISSOURI   B-00587, C-00482, F-00530
MISTS  A-13403, B-00587, B-00800,
      B-02355, B-02985, B-03945, B-05079,
      B-05514, B-05567, B-06247, B-07552,
      B-07925, B-11058, B-11235, B-11238,
      B-13667, B-17889, B-19370, B-19594,
      B-19682, B-23556, B-24110, B-24256,
      B-24695, B-24833, B-25370, B-25717,
      B-26095, C-00040, C-01387, C-03035,
      C-09295, C-11089, C-11140, C-12596,
      C-14486, C-23771, D-05152, F-00530,
      F-22154, G-23930
MONITORING  B-07925, B-20248, C-00381,
      C-01387, C-01819, C-12596, C-21056,
      C-21415, C-25851, D-05152, G-11379
MONTHLY  K-19750
MORBIDITY  F-00530
MORTALITY  F-00530, 1-20820


                  N

NAPHTHALENES  B-11058
NASHVILLE  F-00530
NATURAL GAS B-11629, B-19886
NERVOUS SYSTEM  G-11379, G-22594
NEW YORK STATE  K-06349
NICKEL  B-11146
NICKEL COMPOUNDS  C-09369, F-14626
NITRATES  B-23070, C-09369, C-23771,
      E-21791, F-14871
NITRIC ACID  A-18305, B-00587, B-01125,
      B-03129, B-07535, B-07552, B-07925,
      B-11058, B-14533, B-14568, B-26254,
      C-23771, J-17203, L-05407,  L-11242
NITRIC OXIDE (NO)  B-01125, B-07535,
      B-11058, C-00040, C-00381, C-09369,
      E-21791, F-10907, F-20274
NITROGEN  B-21703, C-11089
NITROGEN DIOXIDE (NO2)  B-00800,
      B-01125, B-07552, B-11058, C-00040,
      C-00381, C-09369, C-09983, C-14486,
      C-24970, E-21791, F-10907,  K-19750
NITROGEN OXIDES  A-13403, B-00800,
      B-01125, B-02355, B-07535,  B-07552,
      B-07925, B-08181, B-11058,  B-14533,
      B-19370, B-19593, C-00040,  C-00381,
      C-09369, C-09983, C-14486,  C-17700,
      C-24970, D-11492, E-21791,  F-10907,
      F-20274, J-17203, J-21206, K-19750,
      L-24033
NITROUS ACID C-24970
NON-INDUSTRIAL EMISSION SOURCES
      A-04946, A-15517, B-00800,  B-03129,
      B-07535, B-11058, B-11238,  B-26254,
      F-00530, L-11242, L-25520,  N-04845
NON-URBAN AREAS  B-11906, F-00530,
      K-06349
                  o
OCCUPATIONAL HEALTH  B-04067
ODOR COUNTERACTION  B-07535
ODORS  B-03129, B-26254, G-22594,
     K-06349
OIL BURNERS  A-23044
OLEFINS  B-03129, B-07925
OPEN HEARTH FURNACES  B-05567,
     B-26254
OPERATING CRITERIA  A-12823
OPERATING VARIABLES  A-12823,
     B-19644, B-20416, B-21309,  B-21824,
     B-24103, B-24256, B-25643,  F-22098
ORGANIC ACIDS  B-25742
ORGANIC NITROGEN COMPOUNDS
     B-01125, B-15879, B-15991,  B-19856,
     B-24594
ORGANIC SULFUR COMPOUNDS
     B-07925, B-24594, B-26254
ORLON  B-05079
OWENS JET DUST COUNTERS  C-03035
OXJDANTS  C-09633, E-21791, K-06349,
     K-19750
OXIDATION  A-10749, B-09126, B-11906,
     E-21791, F-04626, F-10907
OXIDES  A-02235, A-04946, A-10749,
     A-12633, A-12823, A-13403, A-13596,
     A-13841, A-13850, A-18305, A-23972,
     A-25605, B-00800, B-01125,  B-02355,
     B-05079, B-05567, B-06282,  B-07535,
     B-07552, B-07925, B-08181,  B-09126,
     B-09559, B-09913, B-11058,  B-11235,
     B-11238, B-11250, B-11906,  B-13206,
     B-13337, B-13667, B-13880,  B-14533,
     B-15846, B-16289, B-16290,  B-16291,
     B-16480, B-16718, B-17887,  B-19370,
     B-19383, B-19486, B-19593,  B-19594,
     B-19595, B-20024, B-20248,  B-21703,
     B-22055, B-23070, B-24594,  B-24628,

-------
56
SULFURIC ACID MANUFACTURING
     B-24673, B-25370, B-25491, B-26254,
     C-00040, C-00381, C-00482, C-01819,
     C-03852, C-09033, C-09295, C-09369,
     C-09983, C-11089, C-11140, C-12596,
     C-14486, C-14735, C-17700, C-19384,
     C-20595, C-21056, C-21415, C-24970,
     C-25851, D-05152, D-11492, E-21791,
     F-00530, F-04626, F-10907, F-13802,
     F-13875, F-13940, F-14249, F-14526,
     F-14538, F-14539, F-14625, F-14626,
     F-14641, F-14653, F-14845, F-15325,
     F-16292, F-16377, F-20274, F-21068,
     F-22154, G-11379, G-16774, G-17623,
     G-22594, G-23930, 1-20820, J-17203,
     J-21206, J-21308, K-06349, K-19750,
     L-05407, L-24033, N-04845
OXYGEN  A-13596, B-09126, B-13880,
     B-22055, E-21791, F-04626, F-10907,
     F-13875
OXYGEN LANCING  B-07535
OZONE B-00800, B-19943, C-09369,
     C-12596, C-20595, E-21791
PACKED TOWERS  B-08181, B-15879,
      B-22055, B-24110, L-24033
PAPER MANUFACTURING  A-15517,
      B-03129, B-16447
PARTICLE COUNTERS  C-03035
PARTICLE GROWTH  D-05152
PARTICLE SHAPE  G-16774
PARTICLE SIZE  B-00587, B-00800,
      B-05514, B-07552, B-22943, B-24110,
      B-24256, B-24695, B-24833, B-25643,
      B-26095, C-00482, C-01387, C-03035,
      C-09033, C-09633, C-23771, D-05152,
      G-16774
PARTICULATE CLASSIFIERS  B-00587,
      B-00800, B-05514, B-07552, B-22943,
      B-24110, B-24256, B-24695, B-24833,
      B-25643, B-26095, C-00482, C-01387,
      C-03035, C-09033, C-09633, C-23771,
      D-05152, F-00530, G-16774
PARTICULATE SAMPLING   B-20248,
      C-00482, C-09033, C-23771, C-25445
PARTICULATES  A-04946, A-13403,
      A-25605, B-00587, B-00800, B-01125,
      B-02355, B-02985, B-03129, B-03945,
      B-04067, B-05079, B-05514, B-05567,
      B-06247, B-06282, B-07535, B-07552,
      B-07925, B-11058, B-11235, B-11238,
      B-11906, B-13667, B-14568, B-15879,
      B-15991, B-17889, B-19370, B-19383,
      B-19594, B-19606, B-19682, B-20777,
      B-21824, B-22943, B-23556, B-24110,
      B-24256, B-24695, B-24833, B-25370,
      B-25643, B-25717, B-26095, B-26254,
      C-00040, C-00381, C-00482, C-01387,
      C-01819, C-03035, C-09033, C-09295,
      C-09633, C-09983, C-11089, C-11140,
      C-12596, C-14486, C-20595, C-22645,
      C-23771, C-25445, D-05152, E-21791,
      F-00530, F-22154, G-11379, G-16774,
      G-17623, G-22594, G-23930, 1-20820,
      J-17203, J-21206, K-06349, K-19750,
      L-05407, L-24033, N-04845
PATHOLOGICAL TECHNIQUES  G-11379,
      G-23930
PENELEC (CONTACT PROCESS)  A-18305
PENNSYLVANIA  F-00530, K-19750
PEROXIDES  C-09369, C-21056, C-21415,
      C-25851
PEROXYACETYL  NITRATE   E-21791
PEROXYACYL NITRATES E-21791
PESTICIDES  F-00530
    PETER SPENCE PROCESS (CLAUS)
          B-09913, B-24246, L-24033
    PETROLEUM PRODUCTION  B-00800,
          B-07925
    PETROLEUM REFINING  A-15517,
          B-07925, B-19033, B-24673, 1-20820,
          L-10998, L-11242
    PH  B-19469, B-19644, B-25491, C-09033,
          C-09633, D-05152
    PHENOLS  C-09983
    PHOSPHATES  A-04946, B-03129, C-23771,
          L-11242
    PHOSPHINE  C-09369
    PHOSPHORIC ACID  A-18305, B-00587,
          B-07552, B-09559, B-11058, B-25717,
          B-26095, C-14486, C-23771
    PHOSPHORUS COMPOUNDS  A-04946,
          B-03129, B-11058, C-09369, C-23771,
          L-11242
    PHOTOCHEMICAL REACTIONS  E-21791
    PHOTOMETRIC METHODS C-12596,
          C-25851
    PHOTOSYNTHESIS  F-00530
    PHYSICAL STATES  A-04946, B-00587,
          B-00800, B-03945, B-05079, B-05514,
          B-07552, B-09913, B-11235, B-11238,
          B-13728, B-14533, B-14568, B-15879,
          B-15991, B-19682, B-19856, B-20777,
          B-22182, B-23264, B-23556, B-24110,
          B-25717, B-25768, C-01387, C-09633,
          D-05152, F-10907, F-13652, F-15325,
          F-15416, F-22154, G-11379
    PHYTOTOXICANTS  F-00530, N-04845
    PILOT PLANTS  B-23070, B-23556, B-25468
    PLANNING AND ZONING  A-21221,
          L-05407
    PLANS AND PROGRAMS  A-04946,
          B-03129, B-20248, C-01819, L-05407
    PLANT DAMAGE  A-25605, C-24970,
          E-21791, F-00530, 1-20820, L-24033,
          N-04845
    PLANT GROWTH  F-00530
    PLANTS (BOTANY)  C-24970, F-00530,
          N-04845
    PLASTICS  B-03129
    PLATINUM A-13841, A-13850, F-13802,
          F-14538, F-14845
    PLUME BEHAVIOR  D-11492, E-10751,
          F-00530
    PNEUMOCONIOSIS  B-04067
    PNEUMONIA  G-11379
    POINT SOURCES   E-10751
    POLAROGRAPHIC METHODS  C-09983,
          C-15745
    POLYNUCLEAR COMPOUNDS  B-11058
    PORTABLE C-23771
    POTASSIUM COMPOUNDS B-22182
    POTENTIOMETRIC METHODS  C-12596,
          C-14735
    POWER SOURCES  B-07535
    PRECIPITATION  C-09369, N-04845
    PRESSURE  B-00587, B-08181, B-11058,
          B-23556, B-24110, B-25768, D-11492
    PRIMARY METALLURGICAL
          PROCESSING  A-04946, A-10749,
          A-12751, A-12823, A-15517, A-21221,
          A-25178, A-25605, B-05567, B-07925,
          B-09559, B-11146, B-13672, B-19469,
          B-20248, B-21309, B-23939, B-24451,
          B-24673, B-25275, B-26254, 1-20820,
          1-24160, J-21308, L-10998, L-11242,
          L-24033
    PRIMATES  G-23930
    PROCESS MODIFICATION  A-10749,
          B-06282, B-07925, B-09126, B-11058,
          B-11906, B-13728, B-16718, B-21824,
          B-23939, B-25491
    PROTEINS  G-11379
PULMONARY FUNCTION  F-00530,
      G-16774, G-23930, 1-20820
PULMONARY RESISTANCE  G-16774,
      1-20820
QUINOLINES B-19856


                  R

RABBITS  1-20820
RADIOACTIVE RADIATION  C-01387,
     C-11140, K-06349
RADIOGRAPHY  F-16292
RADON  C-09369
RATS  G-11379
REACTION KINETICS  A-13841, B-16290,
     B-16480, B-19486, B-19943, B-20024,
     B-25133, E-21791, F-04626, F-10907,
     F-13652, F-14538, F-16377
REACTION MECHANISMS  B-13880,
     E-21791, F-04626, F-20274
RECREATION AREAS  K-06349
REDUCTION  A-10749, A-12751, A-12823,
     B-01125, B-19886, B-24673, F-14506
REGULATIONS  B-03129, B-24833,
     K-19750
REINLUFT PROCESS (ADSORPTION)
     B-14660
RESEARCH METHODOLOGIES  F-00530
RESIDENTIAL AREAS  K-06349
RESPIRATORY DISEASES  B-04067,
     F-00530, G-11379, G-16774, L-05407,
     N-04845
RESPIRATORY FUNCTIONS  F-00530,
     G-11379, G-16774, G-23930, 1-20820
RESPIRATORY SYSTEM  F-00530,
     G-11379, G-17623, 1-20820, L-05407
SAMPLERS  B-00800, B-22943, C-00040,
     C-00482, C-01819, C-03035, C-09033,
     C-09633, C-09983, C-11089, C-15745,
     C-23771, C-25445, C-25851, D-05152
SAMPLING METHODS  B-00800, B-02355,
     B-20248, B-22943, C-00040, C-00482,
     C-01819, C-03035, C-09033, C-09633,
     C-09983, C-11089, C-15745, C-19384,
     C-22645, C-23771, C-24970, C-25445,
     C-25851, D-05152
SAMPLING PROBES  C-00040
SCREEN FILTERS  B-24110
SCRUBBERS  A-04946, A-12751, A-12823,
     A-23044, B-00587, B-00800, B-01125,
     B-05079, B-07535, B-07925, B-08181,
     B-11058, B-11629, B-13337, B-13667,
     B-14568, B-15879, B-15991, B-17889,
     B-19383, B-19469, B-19644, B-20248,
     B-22055, B-22943, B-23556, B-24110,
     B-24594, B-24673, B-24695, B-24833,
     B-25768, C-25851, F-00530, J-21206,
     L-24033
SEASONAL B-11250
SEDIMENTATION  B-25717, F-00530
SETTLING CHAMBERS  A-25605
SETTLING PARTICLES  A-13403, B-04067,
     B-05079, B-06282, B-07535, B-07925,
     B-11058, B-11906, B-17889, B-20777,
     B-22943, B-24110, B-25643, B-26254,
     C-00040, C-09983, C-20595, C-23771,
     J-17203, K-06349, K-19750, L-05407
SEWAGE B-11238
SILICON COMPOUNDS  B-07552, B-24695
     C-09983

-------
                                                     SUBJECT INDEX
                                                                                 57
 SILICON DIOXIDE  C-09983, F-13875,
      F-14626
 SILICOSIS  B-04067
 SINTERING  A-04946, A-10749
 SKIN  F-00530
 SLAUGHTERHOUSES  B-26254
 SLUDGE  B-11238
 SMOG  B-07535, E-21791, F-00530,
      G-17623, 1-20820
 SMOKES  A-25605, B-07535, B-07925,
      B-15879, B-15991, J-17203, K-06349
 SMOKING  F-00530
 SOCIAL ATTITUDES  F-00530
 SOCIO-ECONOMIC FACTORS A-25178,
      L-25520
 SODIUM CARBONATE  B-15991, B-23264
 SODIUM COMPOUNDS  A-18305, B-15879,
      B-15991, B-22182, B-23264,  B-25491,
      B-25742, C-03035, C-03852,  F-10907,
      F-14871
 SODIUM HYDROXIDE  A-18305, B-22182,
      B-25491, C-03035, F-10907
 SOILING  1-20820
 SOILING INDEX  F-00530
 SOLAR RADIATION  B-07535, E-21791
 SOLID  WASTE DISPOSAL  A-15517,
      B-26254
 SOOT  C-09983, L-05407
 SOOT FALL  L-05407
 SOURCE SAMPLING  B-02355, C-00040
 S02 REMOVAL (COMBUSTION
      PRODUCTS)  A-12751, A-12823,
      A-13403, A-15517, A-18305, A-23044,
      A-23972, A-25605, B-07535, B-09913,
      B-11058, B-11250, B-11629,  B-11906,
      B-13206, B-13337, B-13672,  B-13806,
      B-14030, B-14660, B-15739,  B-15879,
      B-15991, B-17053, B-17810,  B-17889,
      B-19033, B-19228, B-19469,  B-19592,
      B-19595, B-19606, B-19644,  B-19856,
      B-19886, B-19943, B-20248,  B-20416,
      B-20670, B-20777, B-21309,  B-21824,
      B-22182, B-22943, B-23070,  B-23264,
      B-23939, B-24103, B-24246,  B-24451,
      B-24594, B-24628, B-24673,  B-24695,
      B-25133, B-25275, B-25468,  B-25491,
      B-25742, B-25768, F-00530,  F-13652,
      1-24160,  J-17203, J-21206, L-24033
 SPECTROMETRY B-20248, C-l 1140,
      C-12596, F-20274, F-22154
 SPECTROPHOTOMETRY   C-00381,
      C-09033, C-09295, C-11089,  C-125%,
      C-20595
 SPOT TESTS  C-14486
 SPRAY  TOWERS  B-14568, B-22055
 SPRAYS  A-13403, C-00040
 ST LOUIS   B-00587, C-00482, F-00530
 STABILITY (ATMOSPHERIC)  A-04946,
      B-07535, E-10751, E-21791,  F-00530
 STACK  GASES  A-04946, A-12751,
      A-12823, A-15517, A-23044,  A-25605,
      B-00800, B-OI125, B-03945,  B-07925,
      B-11250, B-11629, B-11906,  B-14568,
      B-14660, B-15739, B-16718,  B-17053,
      B-19370, B-19469,  B-19592,  B-19606,
      B-19644, B-19856,  B-19886, B-22943,
      B-23070, B-23264,  B-24110, B-24246,
      B-24451, B-24628,  B-24673, B-24833,
      B-25133, B-25275,  C-14735, C-17700,
      E-10751, F-20274,  J-21206, J-22397,
      N-04845
STACK  SAMPLING  B-02355, C-00040
STACKS  A-04946, A-23044, A-25605,
      B-00800, B-02355,  B-03945, B-07925,
      B-17053, B-21824,  C-00040, D-05152,
      E-10751, F-20274
STANDARDS  B-03129, B-16718,  D-l 1492,
      G-I1379, K-06349, K-19750,  L-25520
STATE GOVERNMENTS  K-06349,
      K-19750
STATISTICAL ANALYSES  E-10751
STEAM  B-09913, B-14533, B-15879,
      B-15991, F-15325, F-15416
STEAM PLANTS  B-07925, B-11238,
      B-14660, E-10751
STEEL  A-04946, B-05567, B-07925,
      B-20248
SULFATES  B-00800, B-01125, B-17889,
      B-19592, B-19606, B-25491, C-09033,
      C-09369, C-0%33, C-11140, C-15745,
      D-05152, F-04626, F-15325, F-15416,
      G-16774, 1-20820, 1-24160, K-19750,
      N-04845
SULFIDES  A-04946, A-10749, B-00800,
      B-04067, B-07925, B-09559, B-11058,
      B-11629, B-14030, B-17889, B-19033,
      B-19886, B-22943, B-23048, B-23070,
      B-24594, B-26254, C-00040, C-03852,
      C-09369, C-09983, C-20595, F-14626,
      1-20820, J-11791, K-06349, K-19750,
      L-24033, N-04845
SULFITES  B-19383, B-19644, B-25491
SULFUR COMPOUNDS  A-04946, A-10749,
      A-25178, B-00800, B-01125, B-04067,
      B-07925, B-09126, B-09559, B-09913,
      B-11058, B-11146, B-11235, B-11238,
      B-11629, B-11906, B-14030, B-17887,
      B-17889, B-19033, B-19383, B-19592,
      B-19606, B-19644, B-19886, B-22943,
      B-23048, B-23070, B-24246, B-24594,
      B-25491, B-26254, C-00040, C-03852,
      C-09033, C-09369, C-09633, C-09983,
      C-11140, C-15745, C-20595, D-05152,
      F-04626, F-10907, F-14626,  F-15325,
      F-15416, G-16774, 1-20820, 1-24160,
      J-11791, J-21308, J-22397, K-06349,
      K-19750, L-10998, L-11242, L-24033,
      N-04845
SULFUR DIOXIDE  A-02235, A-04946,
      A-10749, A-12823, A-13403, A-13596,
      A-13841, A-23972, B-00800, B-01125,
      B-02355, B-05567, B-06282, B-07535,
      B-07552, B-07925, B-09126, B-09559,
      B-09913, B-11058, B-11238, B-11250,
      B-11906, B-13206, B-13337, B-13667,
      B-13880, B-15846, B-16289, B-16290,
      B-16291, B-16480, B-16718, B-17887,
      B-19383, B-19486, B-20024, B-21703,
      B-22055, B-25370, C-00040, C-00381,
      C-00482, C-01819, C-03852, C-09033,
      C-09369, C-09983, C-11089, C-11140,
      C-125%, C-14486, C-14735, C-17700,
      C-20595, C-21056, C-21415, C-24970,
      C-25851, D-05152, E-21791, F-00530,
      F-04626, F-13802,  F-13940, F-14249,
      F-14526, F-14538,  F-14539, F-14625,
      F-14626, F-14641,  F-14653, F-14845,
      F-16292, F-16377,  F-21068, G-16774,
      G-17623, G-22594, G-23930, 1-20820,
      J-21308, K-06349, K-19750, L-05407,
      N-04845
SULFUR OXIDES A-02235, A-04946,
      A-10749, A-12633, A-12823, A-13403,
      A-13596, A-13841, A-18305, A-23972,
      A-25605, B-00800, B-01125, B-02355,
      B-05567, B-06282, B-07535, B-07552,
      B-07925, B-09126, B-09559, B-09913,
      B-11058, B-11235, B-11238, B-11250,
      B-11906, B-13206, B-13337, B-13667,
      B-13880, B-14533, B-15846, B-16289,
      B-16290, B-16291, B-16480, B-16718,
      B-17887, B-19370, B-19383, B-19486,
      B-19594, B-19595, B-20024, B-21703,
      B-22055, B-24628, B-25370, B-25491,
      B-26254, C-00040,  C-00381, C-00482,
      C-01819, C-03852, C-09033, C-09295,
      C-09369, C-09983, C-11089, C-11140,
      C-125%, C-14486, C-14735, C-17700,
      C-19384, C-20595, C-21056, C-21415,
      C-24970, C-25851, D-05152, E-21791,
      F-00530, F-04626, F-13802, F-13940,
      F-14249, F-14526, F-14538, F-14539,
      F-14625, F-14626, F-14641, F-14653,
      F-14845, F-16292, F-16377, F-20274,
      F-21068, F-22154, G-11379, G-16774,
      G-17623, G-22594, G-23930, 1-20820,
      J-21206, J-21308, K-06349, K-19750,
      L-05407, L-24033, N-04845
SULFUR OXIDES CONTROL  A-02235,
      A-04946, A-12751, A-12823, A-13403,
      A-15517, A-18305, A-23044, A-23972,
      A-25178, A-25605, B-00800, B-02355,
      B-02985, B-07535, B-09559, B-09913,
      B-11058, B-11250, B-11629, B-11906,
      B-13206, B-13337, B-13672, B-13806,
      B-14030, B-14386, B-14660, B-15739,
      B-15846, B-15879, B-15991, B-17053,
      B-17810, B-17887, B-17889, B-19033,
      B-19228, B-19469, B-19592, B-19595,
      B-19606, B-19644, B-19856, B-19886,
      B-19943, B-20248, B-20416, B-20670,
      B-20777, B-21309, B-21703, B-21824,
      B-22182, B-22943, B-23070, B-23264,
      B-23939, B-24103, B-24246, B-24451,
      B-24594, B-24628, B-24673, B-24695,
      B-25133, B-25275, B-25468, B-25491,
      B-25742, B-25768, F-00530, F-13652,
      1-24160, J-11791, J-17203, J-21206,
      L-10998, L-24033
SULFUR TRIOXJDE  A-02235, A-13841,
      A-25605, B-00800, B-01125, B-06282,
      B-07535, B-07552, B-09126, B-09913,
      B-11058, B-11235, B-11238, B-11250,
      B-11906, B-13667, B-16718, B-17887,
      B-19594, B-19595, B-22055, B-24628,
      B-25370, B-25491, C-00040, C-00482,
      C-09033, C-09295, C-09369, C-11089,
      C-11140, C-125%, C-14735, C-19384,
      C-20595, C-24970, F-00530, F-04626,
      F-13802, F-14526, F-14538, F-14539,
      F-14653, F-14845, F-16292, F-21068,
      F-22154, G-16774, 1-20820
SULFURIC ACID  A-02235, A-04946,
      A-10749, A-12633, A-12751, A-12823,
      A-13403, A-135%, A-13841, A-13850,
      A-15517, A-18305, A-21221, A-23044,
      A-25178, A-25605, B-00587, B-00800,
      B-01125, B-02355, B-02985, B-03129,
      B-03945, B-04067, B-05079, B-05514,
      B-05567, B-06247, B-06282, B-07535,
      B-07552, B-07925, B-08181, B-09126,
      B-09559, B-09913, B-11058, B-11146,
      B-11235, B-11238, B-11250, B-11629,
      B-11906, B-13206, B-13337, B-13667,
      B-13672, B-13728, B-13806, B-13880,
      B-14030, B-14386, B-14533, B-14568,
      B-15739, B-15846, B-15879, B-15991,
      B-16289, B-16290, B-16291, B-16447,
      B-16480, B-16718, B-17053, B-17810,
      B-17887, B-17889, B-19033, B-19228,
      B-19370, B-19383, B-19486, B-19592,
      B-19593, B-19594, B-19595, B-19606,
      B-19644, B-19682, B-19856, B-19943,
      B-20024, B-20248, B-20416, B-20670,
      B-20777, B-21309, B-21703, B-21824,
      B-22055, B-22182, B-22943, B-23048,
      B-23070, B-23264, B-23556, B-23939,
      B-24103, B-24110, B-24246, B-24256,
      B-24451, B-24594, B-24628, B-24673,
      B-24695, B-24833, B-25133, B-25275,
      B-25370, B-25468, B-25491, B-25643,

-------
58
SULFURIC ACID MANUFACTURING
     B-25717, B-25742, B-25768, B-26095,
     B-26254, C-00040, C-00381, C-00482,
     C-01387, C-01819, C-03035, C-03852,
     C-09033, C-09295, C-09369, C-09633,
     C-09983, C-11089, C-11140, C-12596,
     C-14486, C-14735, C-15745, C-19384,
     C-20595, C-21056, C-21415, C-22645,
     C-23771, C-24970, C-25445, C-25851,
     D-05152, D-11492, E-10751, E-21791,
     F-00530, F-04626, F-10907, F-13652,
     F-13802, F-13875, F-13940, F-14249,
     F-14506, F-14625, F-14626, F-14641,
     F-14653, F-14845, F-14871, F-15325,
     F-15416, F-16292, F-16377, F-20274,
     F-21068, F-22098, F-22154, G-11379,
     G-16774, G-17623, G-22594, G-23930,
     1-20820, 1-24160,  J-11791, J-17203,
     J-21206, J-21308,  J-22397, K-06349,
     K-19750, L-05407, L-10998, L-11242,
     L-25520, N-04845
SUPERSATURATION  B-19682
SURFACE COATINGS   C-03035
SURFACE PROPERTIES  F-21068
SUSPENDED PARTICULATES  A-13403,
     A-25605, B-00587, B-00800, B-01125,
     B-02355, B-02985, B-03129, B-03945,
     B-05079, B-05514, B-05567, B-06247,
     B-07535, B-07552, B-07925, B-11058,
     B-11235, B-11238, B-11906, B-13667,
     B-15879, B-15991, B-17889, B-19370,
     B-19383, B-19594, B-19606, B-19682,
     B-21824, B-23556, B-24110, B-24256,
     B-24695, B-24833, B-25370, B-25643,
     B-25717, B-26095, C-00040, C-00381,
     C-01387, C-03035, C-09295, C-09633,
     C-11089, C-11140, C-12596, C-14486,
     C-23771, D-05152, E-21791, F-00530,
     F-22154, G-17623, G-23930, 1-20820,
     J-17203, K-06349, K-19750
SWEDEN  A-02235, A-18305, B-00587,
     B-00800, B-03945, B-24451, B-25275,
     C-00381, C-00482, E-10751, F-00530,
     F-04626
SYNERGISM  G-11379, G-16774
SYNTHETIC FIBERS  B-03129, B-05079,
     B-24695
TECHNICAL SOCIETIES  L-05407
TEMPERATURE B-07552, B-09126,
          B-11058, B-11238, B-19886, B-22055,
          B-22182, B-23070, B-25468, B-25742,
          C-00482, C-09033, F-13802, F-13875,
          F-16292, F-20274, F-22154
    TEMPERATURE (ATMOSPHERIC)
          D-11492
    TENNESSEE  F-00530
    TESTING FACILITIES  C-00381, C-09983,
          F-00530, G-16774
    TEXTILE MANUFACTURING  B-11058,
          F-14871, L-24033
    TEXTILES  B-03129, B-05079, B-05567,
          B-07552, B-24695
    THERMODYNAMICS  B-16480, B-20024,
          F-13802, F-13875, F-14626, F-14641,
          F-14653
    THRESHOLDS  G-22594, 1-20820
    TIN COMPOUNDS  F-14539
    TISSUES  F-00530
    TITANIUM COMPOUNDS  B-05079
    TOLUENES  B-07925
    TOPOGRAPHIC INTERACTIONS  E-10751
    TOXIC TOLERANCES  C-24970, F-00530
    TOXICITY   G-11379, G-16774, 1-20820
    TRACHEA   F-00530, G-11379
    TRANSPORTATION  A-21221, B-07535,
          F-00530, L-24033
    TREATED FABRICS B-24695
    TREATMENT AND AIDS   F-16292
    TREES  C-24970, F-00530
    TURBIDIMETRY  D-05152
    TURBULENCE (ATMOSPHERIC)  F-00530


                       U

    ULTRAVIOLET RADIATION  E-21791
    UNITED STATES B-09126, F-00530
    URBAN AREAS  A-18305,  B-16447,
          C-01387, C-01819, C-09633, D-05152,
          D-11492, K-06349
    URINALYSIS  F-00530, G-11379
    USSR  A-13403, B-04067, B-08181, B-14386,
          B-14568, B-16289, B-16290, B-16291,
          B-16447, B-16480, B-19682, B-19856,
          B-19943, B-20024, B-23070, B-23939,
          B-24256, C-09295, C-17700, F-13652,
          F-13875, F-13940,  F-14526, F-14538,
          F-14539, F-14625,  F-14626, F-14641,
          F-14653, F-15325,  F-15416, F-16292,
          F-16377, G-11379, G-17623, G-22594
VALLEYS  F-00530
VANADIUM  F-14845
VANADIUM COMPOUNDS  B-09126,
      B-16480, B-19486, B-23070, F-14538,
      F-16377, F-21068
VAPORS  B-09913, B-11235, B-13728,
      B-14533, B-14568, B-15879, B-15991,
      B-19682, F-15325, F-15416, G-11379
VEHICLES  B-07535, L-24033
VENTILATION  B-04067, B-06282
VENTURI SCRUBBERS  B-01125, B-08181,
      B-25768
VISIBILITY  F-00530, N-04845
VISIBLE RADIATION  E-21791
VOLTAGE  B-23264


                  w

WASHOUT  N-04845
WATER  B-05079, B-07552, B-11235,
      B-19856, B-20777, B-23264, B-23556,
      C-01387, D-05152, F-10907, F-13652
WATER POLLUTION  L-25520
WEST AND GAEKE METHOD  C-00381,
      C-14735, 1-20820
WET CYCLONES  B-22943
WETTING  B-05079
WINDS  A-04946, C-01387, D-11492,
      E-10751
WOOLS  B-05567, B-07552
                  X
X-RAYS  C-11140
XYLENES  B-07925
YOKOHAMA  F-00530
ZINC A-04946, B-09559, B-11906, B-21309
ZINC COMPOUNDS  A-04946, A-12751,
     A-12823, A-13596, A-25178,

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