> • I IB I Air Pollution Aspects of Emission Sources SULFURIC ACID MANUFACTURING A Bibliography with Abstracts i ••••! I •••••• I U. S. ENVIRONMENTAL PROTECTION AGENCY • •••••••i • •••••••i • •••••••i ------- 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 ------- 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 ------- 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- ------- 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 ------- 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. ------- 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. ------- 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 ------- 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 ------- 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. ------- 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 ------- 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- ------- 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 ------- 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. ------- 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 ------- 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 ------- 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). ------- 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. ------- 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). ------- 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 ------- 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 ------- 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. ------- 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 ------- 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 ------- 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. ------- 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. ------- 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. ------- 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 ------- 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. ------- 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. ------- 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 ------- 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 ------- 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. ------- 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. ------- 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 ------- 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. ------- 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. ------- 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. ------- 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. ------- 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. ------- 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 ------- 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 ------- 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. ------- 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 ------- 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. ------- 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. ------- 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. ------- 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. ------- 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. ------- 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. ------- 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. ------- 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. ------- 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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