EPA-$70/2-73-053-f
August 1973
Environmental Protection Technology Series
RECOMMENDED METHODS OF
REDUCTION, NEUTRALIZATION, RECOVERY OR
DISPOSAL OF HAZARDOUS WASTE
Volume VI Mercury, Arsenic, Cr, Cadmium
Office of Research and Development
U.S. Environmental Protect ion Agency
Washington, D.C. 20460
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EPA-670/2-73-053-f
August 1973
RECOMMENDED METHODS OF
REDUCTION, NEUTRALIZATION, RECOVERY
OR DISPOSAL OF HAZARDOUS WASTE
Volume VI. National Disposal Site Candidate
Waste Stream Constituent Profile Reports -
Mercury, Arsenic, Chromium, and Cadmium Compounds
By
R. S. Ottinger, J. L. Blumenthal, D. F. Dal Porto,
6. I. Gruber, M. J. Santy, and C. C. Shin
TRW Systems Group
One Space Park
Redondo Beach, California 90278
Contract No. 68-03-0089
Program Element No. 1D2311
Project Officers
Norbert B. Schomaker
Henry Johnson
Solid and Hazardous Waste Research Laboratory
National Environmental Research Center
Cincinnati, Ohio 45268
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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REVIEW NOTICE
The Solid Waste Research Laboratory of the National Environmental
Research Center - Cincinnati,,, U.S. Environmental Protection Agency has
reviewed this report and approved its publication. Approval does not
sigrvtfy, that: the contents necessarily reflect the views and policies of
this Laboratory or of the U.S. Environmental Protection Agency,, nor does
mention of trade names of commercial products constitute endorsement or
recommendation for use.
The text of this report is reproduced by the National Environmental
Research Center - Cincinnati in the form received from the Grantee; new
preliminary pages and new pa.ge numbers have been supplied*.
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FOREWORD
Man and his environment must be protected from the adverse
effects of pesticides, radiation, noise and other forms of pollu-
tion, and the unwise management of solid waste. Efforts to protect
the environment require a focus that recognizes the interplay between
the components of our physical environment—air, water, and land.
The National Environmental Research Centers provide this multidisci-
plinary focus through programs engaged in:
• studies on the effects of environmental
contaminants on man and the biosphere, and
• a search for ways to prevent contamination
and to recycle valuable resources.
Under Section 212 of Public Law 91-512, the Resource Recovery
Act of 1970, the U.S. Environmental Protection Agency is charged
with preparing a comprehensive report and plan for the creation of
a system of National Disposal Sites for the storage and disposal of
hazardous wastes. The overall program is being directed jointly by
the Solid and Hazardous Waste Research Laboratory, Office of Research
and Development, National Environmental Research Center, Cincinnati,
and the Office of Solid Waste Management Programs, Office of Hazard-
ous Materials Control. Section 212 mandates, in part, that recom-
mended methods of reduction, neutralization, recovery, or disposal
of the materials be determined. This determination effort has been
completed and prepared into this 16-volume study. The 16 volumes
consist of profile reports summarizing the definition of adequate
waste management and evaluation of waste management practices for
over 500 hazardous materials. In addition to summarizing the defini-
tion and evaluation efforts, these reports also serve to designate a
material as a candidate for a National Disposal Site, if the material
meets criteria based on quantity, degree of hazard, and difficulty of
disposal. Those materials which are hazardous but not designated as
candidates for National Disposal Sites, are then designated as candi-
dates for the industrial or municipal disposal sites.
A. W. Breidenbach, Ph.D., Director
National Environmental Research Center
Cincinnati, Ohio
m
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TABLE OF CONTENTS
VOLUME VI
NATIONAL DISPOSAL SITE CANDIDATE
WASTE STREAM CONSTITUENT PROFILE REPORTS
Mercury, Arsenic, Chromium and
Cadmium Compounds
Page
Mercury and Mercury Compounds
Mercuric Chloride (253), Mercuric Diammonium Chloride (503),
Mercuric Nitrate (255), Mercuric Sulfate (256), Mercury (257) . . 1
Mercuric Cyanide (254) 49
Organic Mercury (258) 55
Arsenic Compounds
Arsenic Trioxide (51) 67
Cacodylic Acid (80), Sodium Cacodylate (382) 79
Calcium Arsenate (87), Copper Arsenate (119), Lead Arsenate (235),
Manganese Arsenate (500), Sodium Arsenate (376), Zinc
Arsenate (453) 91
Calcium Arsenite (88), Copper Acetoarsenite (490), Lead
Arsenite (236), Potassium Arsenite (341), Sodium Arsenite (377),
Zinc Arsenite (454) 115
Magnesium Arsenite (245) 137
Hexavalent Chromium Compounds
Ammonium Chromate (21), Ammonium Dichromate (22), Potassium
Chromate (343), Potassium Dichromate (345), Sodium
Bichromate (379, 388), Sodium Chromate (386) 143
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TABLE OF CONTENTS (CONTINUED)
Page
mie Acid ('114). ..... ., , , ................ 171
Cadmium- and Cadmium Compounds
Cadmium (8-lj),., Cadmium Chloride (83), Cadmium Nitrate (479), Cadmium
Oxide (85-|,. Cadmium Phosphate- (86) , Cadmium Potassium Cyanide ('480),
Cadmium, Pondered (8?), Cadmium Sul fate (481) ...... *.,.,. 181
V-T
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PROFILE REPORT ON
MERCURY AND INORGANIC MERCURY COMPOUNDS
Mercury (257), Mercuric Chloride (253),
Mercuric Nitrate (255), Mercuric Sulfate (256),
Mercuric Pi ammonium Chloride (503)
1. GENERAL
Introduction
Mercury, commonly called quicksilver, was one of the first metals known
to man and has been mined at Almaden, Spain for 27 centuries. In earlier
times, mercury has been mainly used as a decorative (in the form of
cinnabar), as a medical ointment for skin diseases, and as an amalgam for
tin and copper. Introduction of mercury into scientific research occurred
in 1643, with the invention of the barometer by Torricelli. This was
followed in later years by the invention of the mercury thermometer, the
discovery of the use of mercury as a seal for water-soluble gases in gas
analysis, and the preparation of mercury fulminate as a detonator for
explosives. Because of the relatively small scale use of mercury in the
past, mercury and mercury compounds were never considered a real threat to •
the quality of the environment, although the toxic nature of mercury and
its compounds have been known for centuries. Mercury today, however, is
used on a substantial scale in chemical industries, in the manufacture of
paints and paper, in pesticides for agriculture, and in the electrical
industry. With the development of these applications, and the failure to
recognize the hazards associated with seemingly harmless levels of mercury
and inorganic mercury compounds, came serious problems.
First in 1960, it was reported that 111 persons had died or suffered
serious neurological damage near Minamata, Japan, as a result of eating
fish and shellfish which had been contaminated by methyl mercury and
mercuric chloride discharged into Minamata Bay by a plastics manufacturing
plant. In 1965, another poisoning incident was reported in Niigata, Japan,
-------
and in 1966, Swedish studies showed that many species of birds were being
poisoned by mercury. Finally, in the spring of 1970, high levels of mercury
were discovered in fish in Lake St. Clair, on the Canada-United States
border. Canada banned the sale of fish from the lake, and 10 days later
Michigan followed suit. In succeeding months, there followed a series of
bans on fish and seafood containing excessive mercury, legislations against
discharge of mercury into navigable waters, and the cancellations of Federal
registrations of numerous mercury compounds for industrial and agricultural
uses.
It was these several spectacular reported incidents of mercury poisoning
in recent years, and the positive demonstration that inorganic mercury could
be biologically methylated in the natural aquatic environment and subsequently
concentrated up to 3,000 times in fish and other marine organisms, that
finally led to the full realization of the extent of the mercury pollution
problem.
The quantity of mercury used each year in the world increased at a rate
of about 1,800 flasks* per year for the ten-year period previous to 1968.
Most of the increase was due to the U.S. demand, which grew at a rate of
1,600 flasks per year over the same period until in 1968 it represented
about 30 percent of the world primary production of 257,000 flasks. Also
in 1968, the U.S. supply of mercury came from four sources: 18 percent from
recycled material; 36 percent from U.S. mining; 22 percent from net imports;
and 24 percent from Government stockpile releases. Individual statistics
for the production and consumption of inorganic mercury compounds are not
available, but could be estimated from the consumption figures of mercury
by uses (Table 1).
Manufacture
Mercury. The most common metallurgical process for recovering mercury
is that of roasting cinnabar (mercuric sulfide) in either mechanical
*A flask contains 76 Ib mercury and is the standard commercial unit
of trade.
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furnaces or retorts to volatilize the mercury followed by condensation of
the vapor. Furnacing is a continuous operation where the mercury bearing
materials are directly heated by the gases of combustion, and has the
disadvantage of involving large volumes of furnace gas. Retorting, on the
other'hand, is a batch operation where the material is heated indirectly
and consequently the volume of retort gas is small. Hydrometallurgical
processes for extracting mercury include leaching with either sodium
hypochlorite or sodium sulfide, but to date both methods have not been
nercui
.0637
commercially employed for the recovery of mercury. The major U.S.
producers of mercury include the following:
Decoursey Mountain Mining Company; Anchorage, Alaska
Harold Braggini; Atascadero, California
COG Minerals Corp.; Denver, Colorado
New Idria Mining and Chemical Co.; Guerneville, California
. Holly Minerals Corp.; Albuquerque, New Mexico
Rare Metals Corp. of America; Salt Lake City, Utah
Cordero Mining Co.; Palo Alto, California
Arentz-Cornstock Mining Venture; Salt Lake City, Utah
Bonanza Oil and Mining Corp.; Sutherlin, Oregon
Mercuric Chloride. Mercuric chloride is produced commercially by the
direct chlorination of mercury. Older processes, based on the reaction
between mercurous sulfate and sodium chloride, are no longer extensively
1433
practiced in the United States.
Mercuric Nitrate. Mercuric nitrate is made by dissolving mercury in
an excess of hot concentrated nitric acid, followed by cooling to
crystallize the hydrate. Seeding with a small quantity of pure crystals
is usually recommended, as there is a strong tendency to form supersaturated
IA^T
solutions. J
Mercuric Sulfate. Mercuric sulfate is prepared by reacting a paste
of freshly precipitated and washed yellow mercuric oxide with the calculated
amount of sulfuric acid, followed by filtration of the white crystalline
1433
sulfate on a nutsch and subsequent drying. It may also be prepared
by heating mercury with an excess of sulfuric acid; the formation is favored
at high temperatures.
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Mercuric Piammonium Chloride. Mercuric chloride diammine is made by
dissolving mercuric chloride in a strong aqueous solution of ammonium
chloride-,-, and adding ammonia solution. It may also be prepared by treating
finely powdered dry mercuric chloride' with anhydrous ammonia vapor.
The major UvS. producers of inorganic mercury chemicals include the
following0637
Allied Chemical Corp,'; Specialty Chemicals Division; Morristown,
New Jersey
City Chemical Corp.; Jersey City, New Jersey
MaTlnnekrodt Chemical Works, Industrial Chemical Division;
Jersey City, New Jersey
Merck & Co., Inc., Merck Chemical Division, Rahway, New Jersey
Troy Chemical Corp.; Newark, New Jersey
Ventron Corp., Alfa Products; Beverly, Massachusetts-
Ventron Corp., Chemicals Division; Beverly, Massachusetts
Uses
The U.S. demand for mercury can be broken down into recyclable and
dissipative uses, which account for 74 and 26 percent of the total
respectively. Recyclable uses are defined as those for which it is
technically feasible to recycle, whereas for dissipative uses it is not.
The major use of mercury is as a cathode in the electrolytic
preparation of chlorine and caustic soda. Actual consumption in this
manufacturing process is small for each unit, although up until recently
large quantities Were required for new installations (10 percent of 1968
demand). Because of the many plants now in operation, however, the require-
ment to replace losses has become a major use (23 percent of 1971 demand).
Large quantities of mercury are also used in electrical apparatus, in in-
dustrial and control instruments, and in general laboratory applications.
These potentially recyclable uses of mercury are for fluorescent and high-
pressure mercury lamps, arc rectifiers, mercury battery cells, switches,
thermometers, barometers, diffusion pump, vacuum gage, and as a vibration
1433,2105
damper.
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The largest dissipative use of mercury is for mildewproofing paints.
(Mercury is no longer used in antifoul ing paints). Mercury compounds are
also widely used in agriculture as a result of their broad antifungal
capabilities, for catalytic purposes, and formulated into many of the over-
the-counter cosmetics (such as creams and lotions, hair preparations, and
facial make-up) and patent medicines (antacids, astringents, eye drops,
laxatives, nasal sprays, skin antiseptics, contraceptives). Mercury is
used in dental amalgams, and to a decreasing extent, for the control of
slime in the paper and pulp mills. '
Individual figures of mercury consumption by use from 1967 to 1971
have been compiled by the Bureau of Mines (Table 1), and indicate that
declining levels of consumption were noted for mercury uses in agriculture,
catalysts, electrolytic preparation of chlorine and caustic soda, instal-
lation and expansion of chlor-alkali plants, and paper and pulp manufacture
(Table 2).
An estimate of the current and future use pattern of mercury over the
next few years has also been presented (Table 3). Of the eleven major
categories represented, decreasing demands are forecasted in five including
agriculture, electrolytic preparation of chlorine and soda, installation
and expansion of chlor-alkali plants, paints, and paper and pulp manufacture.
The other six major uses of mercury are expected to continue at about the
same level. These predicted trends in mercury consumption also point toward
the direction where future efforts of mercury recovery and pollution control
should be aimed.
Of the four inorganic mercury compounds included in this Profile Report,
mercuric diammonium chloride is of no commercial significance; whereas
mercuric chloride is one of the most industrially important mercury compounds,
Mercuric chloride is used for the production of various mercuric compounds,
as a catalyst in vinyl chloride manufacture and other organic reactions, and
as a preservative for wood. In agriculture, it is used either as a dust
or spray for the control of certain fungus diseases on seeds. Solutions
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TABLE 1
MERCURY CONSUMED IN THE UNITED STATES BY USES
Consumption ,
Use
Agriculture (includes fungicides and bactericides
for industrial purposes)
Amalgamation
Catalysts
Dental preparations
Electrical apparatus
Electrolytic preparation of chlorine & caustic soda
General laboratory uses
Industrial & control instruments
Paint:
Anti foul ing
Mildew proofing
Paper & pulp manufacture
Pharmaceuticals
Redistilled t
Other +
Total known uses
Total uses unknown
Grand total
1967
3,732
219
2,689
1,359
14,610
14,306
1,133
3,865
152
7,026
446
283
7,129
12,568
69,517
--
69,517
1968
3,430
267
1,914
2 ,089
17,484
17,458
1,246
3,935
392
10,174
417
424
8,247
7,945
75,422
--
75,422
1969
2,689
195
2,958
3,083
18,650
20,720
2,041
6,981
244
9,486
588
724
9,689
78,048
1,056
79,104
flasks
1970
1,812
216
2,041
1 ,799
15,789
14,977
1,513
4,035
193
8,771
316
571
6,521
58,554
2,936
61 ,490
1971
1,477
*
1,141
2,387
16,938
12,262
1,809
4,871
414
8,191
*
682
2,300
52,472
3
52,475
* Withheld to avoid disclosing individual company confi
t "Redistilled" used in industrial instruments, dental
denti al
data; incl
preparations, and
uded with
electrical
"Other".
apparatus.
Figures for the Redistilled category are not available after 1969, but have probably been
broken down and added to the figures of the individual use categories.
"Other" includes mercury used for installation and expansion of chlor-alkali plants.
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TABLE 2
TRENDS IN USES OF MERCURY OVER THE PERIOD 1967 to 1971
1971 Consumption
Use FlasksPercent of Total
Decreasing Level of Consumption
Agriculture 1,477 2.8
Catalysts 1,141 2.2
Electrolytic Preparation of Chlorine
and Soda 12,262 23.4
Other Uses* 2,300 4.4
Subtotal 17,180 32.8
No Significant Changes in Consumption
Dental Preparations 2,387 4.5
Electrical Apparatus 16,938 32.3
General Laboratory Uses 1,809 3.4
Industrial and Control Instruments 4,871 9.3
Paints 8,605 16.4
Pharmaceuticals 682 1.3
Subtotal 35,292 67.2
Grand total 52,472 100.0
*0ther uses include mercury used for installation and expansion of
chlor-alkali plants, amalgamation, and in paper and pulp manufacture.
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TABLE 3
ESTIMATED TRENDS IN CONSUMPTION OF MERCURY
Estimated Mercury
Consumption, flasks
Use 19711974-1975
Agriculture 19477 0
Catalysts 1,141 1,141
Dental Applications 2,387 2,387
Electrical Apparatus 16,938 16,938
Electrolytic Preparation of Chlorine and
Soda 12,262 672*
General Laboratory Use 1,809 1,809
Industrial & Control Instruments 4,871 4,871
Paints 8,605 0
Paper and Pulp 10+ 0
Pharmaceuticals 682 682
Others* 2,290 300
Totals 52,472 28j800
*Based on total mercury loss of 0.02 Ib/ton chlorine produced and a
chlorine production capacity of 7,000 tons per day.
+Estimated
^"Others" include mercury used for installation and expansion of chlor-
al kali plants and amalgamation.
8
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of mercuric chloride are used medicinally as an antiseptic, and in
1433
photography to intensify negatives.
Mercuric nitrate is used in the preparation of other mercury compounds,
and in particular, mercury fulminate. It is also used in the manufacture
of felt, and for the destruction of phylloxera.
Mercuric sulfate is mainly used as an electrolyte for primary
batteries. Aside from its occasional use as a catalyst, mercuric
sulfate has been employed in conjunction with sodium chloride to extract
1433
gold and silver from roasted pyrites.
Sources and Types of Waste
The wide variety of uses of mercury and mercury compounds by man has
resulted in significant mercury pollution of the environment in many parts
of the world. By far the single largest source of commercial discharges
of mercury during 1968 was derived from inventory losses suffered by the
chlor-alkali plants. Approximately 25 percent of the U.S. supply of
chlorine comes from mercury cells, which produce a higher grade caustic
soda that is highly concentrated and essentially free of chloride impurities,
and thus the trend in new construction until recently, has greatly favored
the mercury cell. The total chlorine capacity of mercury cells in the
United States is about 7,000 tons per day from about 29 installations
around the country, with plant capacities ranging from 6 to about 700 tons
per day. In the mercury cell process, a circulating sodium chloride solution
is electrolyzed in the cell in which mercury serves as the cathode; the anode
is usually graphite. Sodium ion reacts with mercury to form an amalgam, and
chlorine gas is produced at the anode. The mercury flows through the cell,
picking up sodium on the way, and is pumped to a regeneration cell, where
the amalgam is mixed with water and forms one-half of a self-shorted electro-
lytic cell, with iron serving as the other electrode. The regeneration cell
removes sodium from the amalgam and produces caustic soda (approximately
50 percent solution) and hydrogen gas. The regenerated mercury is then
returned to the mercury cell, and the process is repeated. The brine
solution leaves the mercury cell and is vacuum de-chlorinated and then
9
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purged with air to remove the last of the chlorine. The solution is then
saturated with salt, and this is followed by a purification step, in which
various impurities from the newly added salt are precipitated. The brine ,,.
is thep passed through a filter and back to the mercury cell.
The primary sources of mercury loss in mercury-cell chlor-alkali plants
are the hydrogen gas stream, the sludge from the brine purification process,
the caustic soda, stream, cell room ventilation air, and various waste wash
water (Table 4).0533' 2042j 2°e2' 2105 The reported values of mercury loss
from Swedish and U.S. plants are 55 to 190 gm/ton and 202 to 538 gm/ton of
chlprine produced respectively 1n 1968, As early as 1970, however, it was
technically feasible to reduce the total mercury loss from a chlor-alkali
plant to only 0.63 to 2.11 gm/ton of chlorine produced.
Based upon 1968 U.S. data, 17,458 flasks of mercury were used in the
manufacture of chlorine, which represents an industry average of about
0.5 Ib of mercury loss per ton of chlorine produced. However, this
loss can apparently be decreased by one to two orders of magnitude by
proper plant management. During the summer of 1970, lawsuit threats and
tentative water standards caused many of the chlor-alkali manufacturers
to reduce their mercury discharge significantly. As monitored by the
Department of Interior, the overall level of mercury emission to receiving
waters was found to be dropped 86 percent from 287 Ib per day in July to
40 Ib per day in September 1970.2105
The major mercury problem associated with the chlor-alkali plants at
present is the safe disposal of the mercury containing brine sludges. For
resaturation of the partly depleted brine from electrolysis, solid salt is
required by the mercury cell process. If only brine is available, this
must be evaporated first to produce solid salt. Typical sources of salt
include shaft mined rock salt vacuum pan salt, solar pond salt, and salt
recovered from the cell liquor evaporator in an adjacent diaphragm cell
plant. The ideal raw material for the mercury cell process is, of course,
highly purified recrystallized salt with a purity of 99.99 + percent Nad.
If the salt feed is of extremely high purity, the brine need only be
filtered before returning it to the cells. If salt recovered from the
10
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TABLE 4
SOURCES OF MERCURY LOSSES
FROM CHLOR-ALKALI PROCESS(0533, 2042, 2062, 2105)*
Source
H2 gas
NaOH
Brine sludge
Ventilation
Wash waters
Others
Total
Sweden
(1967)
27-85
0.4-20
2-50
15-25
10
-
55-190
United States
(1968)
180-230
2-3
5-125
5-45
5-70
5-65
202-538
Technically
feasible
(1970)
0.01-
0.01-0.
0.1-1.0
0.5
0.01-0.
-
0.63-2.
5
1
11
*Grams of mercury lost per ton of chlorine produced.
11
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diaphragm cell caustic evaporators is used, brine purification normally
involves the addition of caustic soda followed by filtration, the sludge
obtained is mainly graphite, along with some CaC03, Mg(OH)2> and iron.
When either high purity recrystallized salt or recovered salt from the
diaphragm cell caustic evaporator is used, smaller quantities of mercury
containing brine sludges are generated. These can often be treated and
disposed of safely on the property.
If rock salt or solar salt is used, the full brine stream is treated
for the removal of Mg, Fe, CaCl« and CaSCh equivalent to the pickup from
the salt dissolved. Brine purification includes the addition of barium
carbonate to remove sulfates, the addition of sodium carbonate or carbon
dioxide to precipitate calcium, the addition of caustic soda to remove
magnesium and heavy metals, and the addition of flocculents to cause
settling of the precipitates. Depending on the impurities initially
present in the salt, the constituents of the brine sludge include barium
sulfate, calcium carbonate, calcium sulfate, magnesium oxide, magnesium
hydroxide, graphite, some iron, aluminum, mud, rocks, and typically 100 ppm
aercury in the form of HgCl/". Mercury losses through the brine sludges
from the mercury cell chlor-alkali plants range from 0.001 to 0.04 Ib per
ton of chlorine produced. The mercury containing brine sludges are cur-
rently being pumped into settling basins awaiting the development and
installation of adequate treatment processes. The total mercury loss is
estimated to be 16,500 Ib per year through 57,000 tons of brine sludges.*
Of the mercury used in 1968 for other potentially recyclable uses,
such as electrical equipment, measurement and control apparatus, and
general laboratory uses, 520 tons were recycled and 660 tons had an unknown
disposition, (in batteries, fluorescent tubes, switches, etc.) and probably
ended up mostly in landfills, dumps, and incinerators.
The dissipative uses of mercury include paints, agriculture, dental
fillings, catalysts, paper and pulp manufacture, and Pharmaceuticals; a
*This is discussed in more detail in the volume on Waste Forms and
Quantities.
12
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total of 26 percent (745 tons) of the mercury demand in 1968. Mercury from
these various uses enter the environment in a variety of ways and at
different rates. For example, although mercury-formulated paints constitute
a considerable source, their release into the environment is rather slow
and probably has a minimal effect. Dental amalgams also apparently have no
measurable effect on the user. On the other hand, mercury catalysts employed
for acetaldehyde and vinyl chloride manufacture and mercury formulations
used as seed dressings have promoted serious consequences, even though such
usage represents a small percentage of the total consumption. However, in
March 1970, the U.S. Department of Agriculture suspended 42 alkylmercury
compounds from interstate commerce. Furthermore, the use of mercury compounds
as slimicides in the paper and pulp industry has decreased drastically since
the early 1960's so that it now amounts to well less than one percent of the
total demand.2105
Other man-made sources of environmental mercury include mine tailings
and vapor released by the mining and smelting of mercury, and a stack loss
cf three percent during the refining process would mean that 31 tons were
emitted into the atmosphere from smelting during 1968. In addition, ore
deposits of heavy metals are generally surrounded by aureoles in which a
notable enrichment in mercury has occurred, and considerable mercury
generally escapes from stacks during the smelting of tin, zinc, copper, and
gold. As an example, zinc concentrates from Tennessee contain an average
of 5 to 10 ppm mercury, thus a single smelter handling 500 tons per day
might emit as much as 10 Ib mercury vapor daily.
Another major source of airborne mercury is the combustion of paper
products and fossil fuel. The actual amounts of mercury in fossil fuels
are quite variable, but preliminary values for U.S. coals average from
0.5 to 3.3 ppm mercury. Since about 550 million tons of coal are
burned in the United States every year, a conservative estimate of 1 ppm
mercury in coal would correspond to an annual release of 550 tons of mercury
to the environment. However, although the general consensus was that fly
ash from coal-burning plants contained negligible amounts of mercury so
that the mercury present in the coal must be released to the atmosphere
during the combustion process, a recent U.S. Bureau of Mines study revealed
13
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that more than 70 percent of the mercury could be trapped by the fly ash
(which ca:h be separated out of the stack gases) and thus be more readily
2172
amenable to recovery. No information is available on the mercury
released during petroleum processing and oil burning, although it is
believed tha't the enormous amounts of these substances consumed and burned
in the United States each yeatr probably contribute a substantial amount to
mercury pollution. Samples from California crudes have yielded mercury
values in the range Of 1.0 to 2T ppm; and related tars which have lost much
of their volatile hydrocarbons are known to contain as much as 500 ppfn
2117
mercury.
Lastly, because mercury has a tendency to vaporize and is widely
distributed, mercury also enters into the environment through natural
sources. The air over mercury ore deposits and precious metal or copper
ore deposits generally contain elevated levels of mercury. Relatively high
concentrations of mdrcury are also likely to occur in underground waters
because of the longer and intimaite contact with mineral grains. Oil field
brines, hot springs, and geothermal stream fields have been as'sociated with
high mercury levels, and hot vapors which stream up through fine-grained
muds produce mud volcanoes and deposit considerable quantities of mercury
2117
during condensation.
Physical and Chemical Properties
The physical and chemical properties of mercury and the four inorganic
mercury compounds are summarized in the attached worksheets.
2. TOXICOLOGY
Inorganic mercury may enter into the body by adsorption through
inhalation of elemental mercury vapor or aerosols of mercuric salts and
by oral ingestion. Penetration through the skin, on the other hand, is
rather slow.
Inhalation of mercury in concentrations of 1,200 to 8,500 micrograms
per cubic meter in air results in acute intoxication, affecting primarily
the digestive system and kidneys * and is characterized by a metallic taste,
14
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nausea, abdominal pain, vomiting, diarrhea, headache, and sometimes
albuminuria. After a few days, the salivary glands swell, stomatitis and
and gingivitis develop, and a dark line of mercuric sulfide forms on the
inflamed gums. Furthermore, teeth may loosen and ulcers may appear on the
lips and cheeks. Severe exposure to mercury vapor produces tightness and
pain in the chest, difficulty in breathing, and coughing. Severe cases of
acute poisoning are characterized in later stages by hemolysis, sleeplessness,
headache, facial tics, digital tremors, delirium and hallucinations. Death
as a result of extreme exhaustion frequently occurs with poisoning of this
degree of severity. In milder cases of acute mercury poisoning, some
patients recover within 10 to 14 days, but others may develop the chronic
symptoms, such as muscular tremors or erethism.
Chronic poisoning of mercury is more common than the acute form. In
the case of chronic poisoning of inorganic mercury, symptoms and signs
involving the central nervous system are most commonly seen, the principal
features being tremors and psychological disturbances. Symptoms related
to the mouth, such as gingivitis, stomatitis, and excessive salivation,
may occur along with a number of nonspecific symptoms such as loss of
appetite, weight loss, anemia, and muscular weakness. Intoxication from
mercury vapor or from absorption of mercuric salts may be due, in both
cases, to the action of the mercuric ion. Metallic mercury is able to
diffuse much more extensively into the blood cells and various tissues
than inorganic mercury, but once distributed, most of it is oxidized to
the mercuric form. Numerous cases of industrial exposure to mercurials
with resultant toxic symptoms have been reported, mostly involving incidents
in the mining of hat-felt industries (which utilizes mercuric nitrate).
In most cases, however, symptoms of mercury poisoning were observed only
among workers who had been exposed to mercury levels above 100 micrograms
per cubic meter in air.
It has been reported that a 1 gm oral dose of mercuric chloride could
2117
cause death in adults whereas a 0.1 gm dose would lead to chronic illness.
The acute oral LD50 of mercuric chloride to rat is 37 mg/kg body weight,
1312
and that of mercuric nitrate to mouse is 4 mg/kg body weight.
15
-------
The American Conference of Governmental Industrial Hygienists (ACGIH)
has recommended as Threshold Limit Values (TLV) for 1971 a time-weighed
average concentration of 50 micrograms per cubic meter in air for metallic
f)99C
mercury vapor and inorganic mercury compounds. The new ACGIH TLV for
inorganic mercury is probably based on the report of the 1968 International
Symposium at the Karolinski Institute, Sweden, which recommended 8-hour
Maximum Allowable Concentrations (MAC) of 50 micrograms per cubic meter in
air for mercury vapor and 100 micrograms per cubic meter in air for inorganic
mercury salts.
The lethal concentrations of mercury compounds for various aquatic
2117
organisms have been summarized in a 1970 U.S. Geological Survey Report.
For mercuric chloride, the lethal concentrations in ppb for aquatic organisms
are: Escherichia coli (bacteria), 200; Schenedismus (phytoplankton), 30;
Microregma (protozoa), 150; Daphnia magna (zooplankton), 6; Marinogammarus
marinus (amphipod), 100; Polycelis nigra (flatworm), 270; Bivalve larve
(mollusca), 27; Australorbis glabratus (mollusca), 1,000; Stickleback (fish),
4 to 20; Guppy (fish), 20; Eel (fish) 27; Rainbow trout (fish), 9,200. For
mercuric nitrate, the lethal concentrations in ppb for aquatic organisms
are: Mesospheroma oregonensis (isopod), 15; Mercierella enigmatica
(polychaete), 1,000; Stickleback (fish), 20; Guppy (fish), 20. No aquatic
toxicity data are available for mercury, mercuric sulfate, or mercuric
diammonium chloride, as mercuric sulfate decomposes in cold water into a
yellow insoluble basic sulfate and free sulfuric acid, and both mercury and
mercuric diammonium chloride are insoluble in cold water. It must be
remembered, however, that mercury and all inorganic mercury compounds
discharged into the aquatic environment could eventually be biologically
converted into the more toxic methyl mercury by anaerobic microorganisms,
' which can then be concentrated through food chains to fish living
in both fresh water and marine environments, thus leading to the present
dimensions of the mercury pollution problem.
3. OTHER HAZARDS
All inorganic mercury compounds, with the notable exception of the
halides, decompose to give toxic fumes of mercury on heating.
16
-------
In addition to its toxic properties, mercuric nitrate also possesses
some of the properties of nitrates. Acetylene forms a sensitive acetylide
when passed into an aqueous solution of mercuric nitrate. Alcohols should
not be mixed with mercuric nitrate, as explosive mercury fulminate may be
formed. Reactions of mercuric nitrate and phosphine give a yellow
precipitate, which explodes when heated or subjected to shock. Mercuric
nitrate also reacts with unsaturates and aromatics with violence if given
time to generate enough heat, and could lead to explosions in its use for
determining sulfur in Ball's reaction.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage, Transportation
Because of the extreme toxicity of mercury and mercury compounds, care
must be exercised in their handling to minimize contact with the skin or the
inhalation of airborne dust, as well as ingestion. Safety precautions should
include adequate ventilation of all work and storage areas, enforcing strict
standards of housekeeping and personal cleanliness, and the use of protective
equipment. Workers should be examined periodically by competent physicians,
and referred to medical treatment after any mishap that might give rise to
an abnormally high intake of mercury.
The volatility of mercury and the dangers of airborne inorganic mercury
salt dusts have necessitated the storage of mercury and inorganic compounds
in tight containers. Mercury, mercuric chloride, and mercuric sulfate are
classified as Poison B by the Department of Transportation (DOT), and the
rules governing its transportation are given in the Code of Federal
Regulations (CFR) Title 49—Transportation, Parts 100 to 199.°278 Although
mercuric nitrate and mercuric diammonium chloride are not on the DOT list
of hazardous materials, the same regulations for Class B Poisons should
also be applied in the transportation of these compounds because of their
toxic nature.
Spilled mercury and inorganic mercury compounds on floors can normally
by handled by several of the removal methods available. Sweeping with
17
-------
special vacuum cleaners can effectively remove large droplets of mercury
and the greater portion of inorganic mercury salt in powder or dust form,
and this can be followed by flooding with water, collection of the water
with suction pumps, and subsequent removal of the mercury from the
contaminated water by chemical precipitation, chemical reduction, ion
exchange, or solvent extraction methods. For the chemical removal of
mercury, a substance is generally applied to react readily with mercury at
ambient temperatures forming nearly nonvolatile mercury compounds, which
can then be swept up. The chemical agents commonly used are inorganic
0533
polysulfides or powdered sulfur.
Methods suggested for treating water spills of mercury and inorganic
mercury compounds include adsorption with activated carbon and ion-exchanger
masses such as the Q-13 resin. Results of experiments conducted at the
Cornell Aeronautical Laboratory (CAL) has shown that an activated'carbon
dose of 500 ppm could effect greater than 99 percent removal of mercury
from water with an initial mercury concentration (as mercuric chloride) of
100 ppm, and it has been suggested the activated carbon could best be
introduced into the stream in water-pe>"meable bags which would allow the
pollutant-laden water to pass through the bag material and interact with
1419
the contained carbon. Ion-exchanger masses that could be employed in
treating water spills of mercury will be discussed later along with other
methods for removing mercury and inorganic mercury compounds from liquids.
Disposal/Reuse
The greater portion of mercury and inorganic mercury compounds present
in air and water waste streams can be removed and the mercury recovered for
its value. However, although zero mercury discharge is the eventual goal
of all concerns, this is not achievable with current technology, especially
when economical factors are also considered. For these reasons, the safe
disposal of mercury and inorganic mercury compounds must still be defined
in terms of recommended provisional limits in the atmosphere and potable
water source and/or marine habitat. The provisional limits are as follows:
18
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Contaminant
in Air
Provisional Limits
Basis for
Recommendation
Mercury
Mercuric Chloride
Mercuric Nitrate
Mercuric Sulfate
Mercuric Diammonium
Chloride
0.0005 mg/MJ
0.0005 mg/M3 as Hg
0.0005 mg/M3 as Hg
0.0005 mg/M3 as Hg
0.0005 mg/M3 as Hg
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
Contaminant in
Water and Soil
Mercury
Mercuric Chloride
Mercuric Nitrate
Mercuric Sulfate
Mercuric Diammonium
Chloride
Provisional Limits
0.005 ppm (mg/1)
0.005 ppm (mg/1) as Hg
0.005 ppm (mg/1) as Hg
0.005 ppm (mg/1) as Hg
0.005 ppm (mg/1) as Hg
Basis for
Recommendation
U. S. Drinking
Water Standard
U. S. Drinking
Water Standard
U. S. Drinking
Water Standard
U. S. Drinking
Water Standard
U. S. Drinking
Water Standard
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
Removal from Gases
Removal of mercury from gases usually concerns one of two types of
operation. The first is removal of mercury vapor from the hydrogen produced
in the mercury-cell chlor-alkali process. The second involves the more
general problem of the removal of mercury vapor from gases such as air,
incineration effluents, and natural gas.
Hydrogen produced by the electrolysis of brine at a mercury cathode
contains substantial quantities of mercury vapor, at times more than 20,000
micrograms of mercury per cubic meter, and is usually saturated with water
vapor. It is desirable to substantially lower the mercury concentrations
in hydrogen, not only from the environmental standpoint, but also because
19
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the presence of mercury at concentrations higher than 10 micrograms per
cubic meter interfere with the use of hydrogen in catalylic reductions of
organic compounds. The common current practice is to remove the greater
portion of the mercury present by initially cooling the hot hydrogen gas
stream (80-120 C) to 5 C before it is sent through other gas treatment
systems. The equilibrium concentration of mercury in the gas phase
changes dramatically with temperature. A reduction in temperature to 5 C
from 80 C will bring the equilibrium concentration in the hydrogen gas
?0fi?
stream down to 3.7 mg per cubic meter from 565 mg per cubic meter.
The removal of mercury vapor from air and other gases is obviously
desirable for health reasons. Health hazards exist if the concentration of
mercury vapor in air rises above the recommended MAC in chemical laboratories
where mercury is used or in plants, such as those utilizing mercury boilers
and leakage of mercury vapor may possibly occur accidentally. Dangerous
concentration may also readily exist in enclosed places due to exposed or
spilled liquid mercury as air saturated with mercury vapor at ordinary
temperatures may contain around 0.015 gm of mercury per cubic meter, far-
exceeding the safe level.
The several methods available for the removal of mercury from gas
streams are discussed below.
Option No. 1^ - Removal with Mist Eliminators. The Brink mist
eliminators developed by the Monsanto Enviro-Chem Systems are being used by
many U.S. chlorine plants, and have been tested over a period of several
months by Georgia-Pacific at its Billingham, Washington plant as part of
that company's overall program to cut mercury emissions, with highly
successful results. ' The hydrogen gas stream containing an
equilibrium mercury concentration of 3.7 mg per cubic meter is sent through
the Brink mist eliminators, which are fiber beds packed between two flat
parallel screens or between concentric cylindrical screens, and 90 to 95
percent of the particulate mercury are removed in a readily recoverable
form. A similar type of filter separators consisting of coalescing filter
elements preceding a mist eliminator has also been recently installed in
well clusters to extract the major portion of the mercury produced with
-------
Dutch natural gas by NAM, the Netherlands producing company and operator of
2049
the giant Groningen gas field. The mercury content of the Groningen
gas at the wellhead is 180 micrograms per cubic meter, and the gas is first
cooled by air and then further cooled to -12 C by Joule-Kelvin expansion.
Much of the mercury in the gas condenses with the water and hydrocarbons
and is drawn off with the condensate, and in the process the mercury content
of the gas discharged from the coolers is reduced to about 40 micrograms
per cubic meter. The tiny droplets of mercury carried in the gas are then
removed efficiently by passing the cooled gas through the coalescing filter
separators, so it is insured that the gas entering the transportation network
contains no more than 12 micrograms per cubic meter of mercury. Although
both the Brink mist eliminator and the NAM coalescing filter separator do
not reduce the mercury concentration in the gas stream to the recommended
MAC level, a second stage unit could be added to remove the last remaining
traces of mercury. For example, Farbenfabriken Bayer has a catalytic
approach capable of reducing the mercury level to less than 1 microgram per
cubic meter and would be ideally suited for this purpose.
Option No. 2 - Adsorption with Molecular Sieves. Although the use of
molecular sieves for the removal of mercury vapor from hydrogen has been
investigated by Logan as early as 1966, it was found that the Union Carbide
Type 13X molecular sieve employed in the study had a very low capacity for
mercury. However, a process called PuraSiv Hg that utilizes a new type
of proprietary molecular sieves has recently been developed and marketed by
Union Carbide's Molecular Sieve Department, and a commercial unit (outside
of Union Carbide) is presently being put on-stream at Sobin Chlor-Alkali's
2in4
Orrington, Maine chlorine plant. The PuraSiv Hg Process can be applied
to any mercury containing gas stream, and consists of three separate skids
mounted in tandem: (1) a blower skid; (2) a chiller/demister skid; and
(3) an adsorption skid. In a typical PuraSiv Hg unit (Figure 1), the
hydrogen gas stream at atmospheric pressure (evolving from the chlorine
plant decomposer system) and containing 10 ppmv mercury first enters the
PuraSiv Hg blower skid, where its pressure is increased by 4 to 5 psi.
The compressed gas next passes through the knock-out pot into the chiller/
demister skid, which consists of a packed chiller unit, a chilled water
heat exchanger, and a Petersen separator. As the hydrogen cools, water and
21
-------
CHILLER/DEMISTER SKID
ADSORPTION SKID
PRODUCT GAS
THE PURASIV-Hfl PROCESS
FROM
DECOMPOSER
BATTERY LIMITS
EXISTING
Figure 1. The Union Carbide PuraSiv Hg Process
-------
elemental mercury mists are formed, and these mists are removed in the
Petersen separator and recycled to the chlorine plant as a liquid stream.
The separator itself consists of stacks (or candles) of ring elements
specially contoured to act as converging-diverging nozzles, and the mist
particles collect on the diverging side of the rings and are washed away
with spray water. The low mist content hydrogen leaves the separator and
enters the adsorption skid, which consists of two adsorber vessels and
auxiliary equipment. Gas enters the "on-line" vessel (while the other bed
is being regenerated) and flows upward through the bed of PuraSiv Hg
adsorbents so that the remaining mercury is trapped. During the first 20
hours of operation, essentially no mercury breaks through the adsorbent bed.
In the remaining 4 hours of the run, however, the effluent concentration
increases gradually to 50 ppbv. Commercial PuraSiv Hg Systems are designed
to be regenerated every 24 hours by heating a portion of the effluent gas
in an electric furnace and.passing it downward through the vessel, thus
stripping out the mercury. The relatively concentrated mercury stream is
then recycled through a water cooled heat exchanger, a knock-out pot, and
into the suction of the blower, with final recovery of the stripped-out
mercury occuring in the demister. PuraSiv Hg Systems are guaranteed to
provide effluent mercury levels averaging less than 60 ppbv for 3 years,
so that the total mercury emitted with the effluent hydrogen from a 300
ton per day chlorine plant will be less than 0.1 Ib per day and below the
proposed Federal Standards for total mercury emission.* This guaranteed
mercury level of 60 ppbv (540 micrograms per cubic meter), however, is
considerably above the level of any acceptable environmental standard for
mercury in air or the permissible level of mercury in hydrogen for industrial
uses. To render the Union Carbide PuraSiv Hg System useful for a wider
range of applications, it is suggested that either the bed volume of the
adsorption vessels be increased or a shorter on-line time for the adsorption
vessels be instituted (this can be accomplished by installing more adsorption
vessels if a regeneration time of 24 hours is required), so that the level
of mercury in the effluent from the adsorbent bed will remain extremely
low (below 1 ppbv) at all times.
*Proposed Federal Standards for Chlorine plants allow 1,000 gm (2.2 Ib)
per day of mercury in the by-product hydrogen and seal air streams (combined)
total).
23
-------
Option No. 3 - Adsorption with Activated Carbon. Although activated
carbon by itself is a relatively inefficient adsorbent for mercury, its
adsorption capacity for mercury can be greatly enhanced by impregnation
with silver, potassium iodide, or any other substance that will react with
mercury.2065' 2066> 2058 However, as only in some instances (such as
adsorption on silver) can the substrate be regenerated by heating to
around 400 C, adsorption with mercury reactant impregnated activated carbon
has not received wide acceptance in the industry. In addition to the
difficulty of adsorbent regeneration, the process is also too expensive and
its efficiency may be drastically reduced by the presence of water.
Option No. 4 - Scrubbing with Oxidizing Solutions. A fourth approach
in removing mercury from gases consists of adsorption with a strongly
oxidizing aqueous solution so as to bring the mercury into solution in the
mercuric state; the mercuric ions can then be removed from solution by
methods such as chemical precipitation, chemical reduction, ion exchange,
?062
or solvent extraction. Although an acid permanganate solution can be
used for this purpose in the same fashion as is done for the analytical
determination of mercury, the introduction of a completely foreign stream
into the system and subsequent recovery of the metal from the loaded
solution will require an additional processing system. A more attractive
alternative, therefore, is to use sodium hypochlorite as the oxidizing
agent. Sodium hypochlorite had been used already for a few processes where
hydrogen had to be purified for use in the preparation of hydrogenated fats
or foodstuffs, or in catalytic reactions where the catalyst was subject to
mercury poisoning. ' The hypochlorite system has been installed
recently by at least one chlor-alkali plant for mercury removal and found
to be highly effective.2062
Other processes for the removal of mercury from gas streams that have
been investigated include adsorption with chromic acid on silica gel,
2085 ^
adsorption with mercury-wettable materials on extended surfaces,
adsorption with fused alumina oxide containing silver, and absorption
with a suspension of manganese dioxide. Chromic acid on silica gel
has a reasonably high capacity for mercury, but this could be significantly
reduced by the presence of water vapor, presumably due to the strong
24
-------
physical adsorption of water molecules on the gel preventing access to
mercury. In the case of adsorption with mercury-wettable materials on
extended surfaces (such as fused alumina oxide), the preferred deposited
adsorbent metal based on affinity for mercury is silver, which has the
disadvantage of being easily poisoned by hydrogen sulfide or chlorine in
the atmosphere. Application of the method on the commercial scale also
remains to be demonstrated. Bench-scale tests have shown that mercury
could be removed from gas streams by adsorption in a suspension of manganese
dioxide, but again the process proved unsuitable for scale-up to the size
2049
of commercial units. These processes are therefore considered as
inadequate methods for the removal of mercury from gas streams.
Removal from Liquids
Various liquid streams in the mercury-cell chlorine plant contain high
concentrations of mercury which must be removed before they could be
discharged to public waters. Depleted brine and the brine sludge formed on
the subsequent treatment with soda and barium chloride are rich in mercuric
2
ions, mostly in the form of the tetrachloro complex (HgCTL ), and mercury
can enter the aquatic environment when either a small portion of the depleted
brine is bled off to prevent continual build-up of sulfate (originally
present in the sodium chloride) concentration in the salt solution or through
dewatering of the brine sludges. The cell room and caustic wash water and
other aqueous solutions that are a part of mercury cell operations also
contain soluble or colloidal mercury, primarily in the elemental form.
Other liquid streams containing inorganic mercury requiring treatment
include: (1) wastewaters from manufacturers of mercury chemicals, chemcial
plants using mercury catalysts, and paper and pulp mills using sodium
hydroxide with a trace of mercury, (2) scrubbing solutions for removing
mercury from gases; (3) leaching solutions for extracting mercury from ores,
sludges and fly ash from combustion of fossil fuels; and possibly (4) sewage
treatment plant effluents as a result of breakage of mercury seals used in
trickling filters, switches, flow meters, and other instrumentation.
Several methods available for the removal of inorganic mercury from
liquids are discussed below.
25
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Option No. 1 - Chemical Precipitation. Inorganic mercury can generally
be removed from liquid solution by direct precipitation as an insoluble
metal salt either with or without further processing. Raising the pH to
the range of 10 to 12 with sodium hydroxide or sodium hypochlorite will
render mercuric oxide, which can then be removed by filtration. Mercury
and mercuric ions could also be precipitated as mercuric sulfide by the
addition of a soluble sulfide or hydrogen sulfide gas to the liquid
solution.2042' 2069' 2070> 2072 Sodium sulfide is generally used, and the
colloidal mercuric sulfide formed could be separated from the liquid stream
through flocculation with ferric chloride. Both these methods, however,
suffer from the fact that precipitation is seldom complete (effluent often
contains 1 ppm mercury) and the fine precipitate formed is difficult to
remove.
Option No. 2- Chemical Reduction. Mercuric ion can be chemically
reduced from various liquid solutions with a variety of agents: alkali
metals, zinc, antimony, iron, aldehydes, hydrazine hydrate, and sodium
borohydride among many others. Direct reduction of mercuric ions by passing
the waste stream and an alkali metal amalgam through either an active bed
of amalgamated steel turnings and pieces or an inert bed whereby additional
amalgam is obtained along with metallic mercury appears to be a unique and
clean way of recovering mercury, but tests so far have indicated that a
2072
relatively high level of mercuric ions remain in the treated effluent. '
One set of results showed that the mercury content was reduced from
15.4 ppm to 3.3 ppm in the "active-bed" treatment and from 10 ppm to 7.2 ppm
in the "inert-bed" treatment. Town described a method of precipitating
elemental mercury from an aqueous sodium sulfide-sodium hydroxide solution
2080
containing mercury by the addition of elemental antimony, but an excess
of antimony is usually required and the amount of mercury left in solution
has not been analyzed. Niepert and Bon suggested the addition of an
aldehyde to waste streams containing mercury compounds and the recovery of
the reduced metallic mercury by settling. The method again proves to
be unsatisfactory because of the high mercury concentration (approximately
1 ppm) remaining in the waste stream after treatment. However, two other
chemical reduction schemes, the Ventron sodium borohydride process and the
use of zinc dusts, appear to be able to improve wastewaters to low ppb
mercury limits.
26
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The Ventron Process. ' ' Sodium borohydride is a powerful
reducing agent capable of reducing both mercuric and mercurous ions to the
metal almost instantaneously. The reaction also has the advantages of
taking place at low temperatures and is not critically pH dependent. In
the Ventron flow scheme (Figure 2) wastewater containing inorganic mercury
compounds is fed with a 12 percent solution of sodium borohydride (in 40
percent caustic soda) into a static mixer. The pH is held between 9 and 11.
The hydride reduces the mercury compounds, yielding metallic mercury
precipitate and hydrogen gas. Following separation of the gas, which is
scrubbed with a dilute nitric acid solution to eliminate any mercury vapor,
the slurry is passed to a cyclone. There 80 to 90 percent of the mercury
comes out as a sludge. The clarified effluent is then sent to polishing
filters where just about all of the remaining mercury is removed; the
recovered metal is purified by vacuum'distillation. A Ventron sodium
borohydride unit has been onstream since January 1971 at its Woodridge,
New Jersey mercury chemicals manufacturing facility. The waste treatment
system presently handles 15,000 gallons per day of an effluent averaging
100 ppm soluble mercury. Experience with actual operation has indicated
that effluent discharge from the Ventron system, after final polishing with
activated carbon followed by chelating resins, contains less than 5 ppb
mercury.
Zinc Reduction. ' Removal of mercury compounds from an aqueous
solution having a pH between 7 and 11 and containing 1 to 500 ppm of dissolved
mercury by contacting a bed of reductor metal (zinc or iron) has been
previously described by Gilbert and Rallis. Mercury is recovered as the
metal and the typical removal efficiency is 90 percent. More recently,
the New Jersey Zinc Company (NJZ) has issued a report discussing the use
of zinc to remove mercury from wastewater, including a summary of the
results obtained by NJZ researchers. As described by NJZ, the simplest
mercury removal method is to add an excess of fine zinc dusts and to keep
the dusts suspended in the solution by constant stirring. The tanks and
stirring blades should be baffled to avoid the formation of an air vortex,
which would result in oxidation and loss of the metallic zinc. The excess
zinc will quickly settle to the bottom of the bank when the agitation
27
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WASTEWATER
SODIUM BOROHYDRIDE
SOLUTION
METERING
TANK
HYDROGEN
DILUTE NITRIC
ACID
SCRJBBER
BASIN
STATIC MIXER
GAS SEPARATOR
EFFLUENT
POLISHING
FILTER
CYCLONE
CLARIFIER
MERCURY
Figure 2. The Ventron Sodium Borohydnde Process
28
-------
stopped. The tank effluent usually still contains a few ppm of zinc, but
zinc is much less toxic to aquatic life and may even act as a desirable
ecological nutrient. The metallic mercury obtained by zinc reduction could
be removed by filtration. A method more applicable to the treatment of
industrial wastewater, however, is to pass the streams containing mercuric
ions through a bed of coarser commercial zinc powders. The metallic mercury
forms an alloy with zinc in the bed, which could be recovered later by
heating the crude alloy, distilling off the mercury, then condensing the
vapors. In the NJZ laboratory investigations, solutions containing 10,000
ppb of mercury (prepared from either mercuric chloride or phenylmercury
acetate) were purified to 20 ppb in 13 seconds, and to 5 ppb in 110 seconds,
by passing them through a 4.7 in. deep bed of granular zinc with average
particle diameters of 2 mm. A slightly deeper bed lowered the mercury
concentration from 10,000 ppb to 2 ppb in 60 seconds. The treatment is
generally effective for streams within a pH range of 5 to 10.
Option No. 3 - Ion Exchange. Ion exchange is another effective method
for removing mercury from liquids. Through the process of adsorbing mercury
on a resin and then eluting it during regeneration, a harmful substance is
removed from a waste stream and transferred to another more concentrated
solution where it can be easily precipitated by conventional techniques. A
few cation exchangers have been reported to be quite successful in extracting
ionic mercury, including the Dowex 500W X-8, the Dowex Al, and the
Oficp ?f)'51
Amberlite IRC-50. Chuveleva et al made studies with the carboxylic
acid resin SG-1 on mercuric nitrate solution, taking advantage of the
stability of the acetate - Hg(II) complex. Cation-exchange resins, however,
have no application in brines where, because of the high chloride
2-
concentration, mercury exists as the HgCl^ anion. Most successful ion
exchange processes for the removal of mercury from liquid, therefore, employ
either anion-exchange or chelating resins. A number of patents exist
describing the use of quaternary ammonium cross-linked resins. Calkins et
al discussed the selective removal of mercuric ions from brines containing
halide ions and metal ions, with an insoluble homopolymer or copolymer
prepared from at least one monomer of the group consisting of vinyphenyl
aliphatic primary and secondary aminomonocarboxylic acids and mixtures
containing a predominant amount by weight of at least one such
-------
aminomonocarboxylic acid and a minor portion of divinyl benzene. As an
example, the effluent brine initially containing 15 ppm of mercuric ions,
after passage through a bed of a copolymer of vinylphenyl glycine and
N,N-pis (vinylbenzyl) glycine was found to contain 0.3 ppm of mercuric ions,
and mercury was recovered from the resin bed by elution with sodium chloride
solution at pH7. Both the Schotten and Prielipp patent and the Grain
2079
and Justice patent discussed the use of a strongly basic anion-exchange
resin of insoluble quaternary ammonium composition to remove mercuric ions
from liquid solution, with typical effluent mercury concentration less
than 0.01 ppm, and regeneration of the ion-exchange resins with aqueous
sulfide solution. Of the commercially developed ion-exchange resins, the
Amberlite IRA-400 has been shown to adsorb significant quantities of
1795
mercury regardless of pH as long as it is present as an am'on. Two
other proven processes in commercial operation, however, are applicable
to most mercury-bearing streams found in the industry. Both the Osaka
Soda Process and the Aktiebolaget Billingsfors-Langed Process also have
the ability to reduce the mercury content in wastewater to less than 5 ppb,
and are discussed in greater detail below.
The Osaka Soda Process.1145' 2045> 2061 In the Osaka Soda Process
(Figure 3), wastewater is first collected in a storage tank, where any
metallic mercury present is allowed to. settle out. It is then chemically
' treated for adjustment of pH and free-chlorine concentration (if necessary),
followed by filtering to remove any floating insolubles. The filtered water
is passed through a tower packed with Osaka Soda's proprietary ion-exchange
resin (IE), and the mercury content of the wastewater is reduced to a
range of 100 to 150 ppb. Next, the waste stream passes through a tower
packed with another Osaka Soda's proprietary resin, designated "MR".
Mercury content is reduced to an undetectable level in the MR tower when
a fresh charge is provided, although the effluent concentration gradually
builds up to 5 ppb and is typically 2 ppb. Mercury values are recovered
from the ion exchanges by periodic stripping. A sodium amalgam or other
agent is then added to the pregnant stripping liquid to reduce the mercury
to metallic form. Generally, IE resin beds are regenerated approximately
once a week, whereas the MR resin is simply discarded several times a year
after recovery of the mercury. Five Japanese chlor-alkali plants, ranging in
30
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WASTEWATER
COLLECTING TANK
STRIPPING CONCENTRATED
LIQUID LIQUID
1
MAKEUP
STRIPPING
LIQUID
STORAGE
TANK
0.2% SODIUM
AMALGAM FROM CELL
REDUCTION
TOWER
0.01% SODIUM
AMALGAM TO CELL
MERCURY
EFFLUENT
Figure 3. The Osaka Soda Mercury Removal Process
31
-------
capacity from 70 to 200 tons per day, have been using the Osaka Soda process
for six years, treating 18,000 to 32,000 gal per day of wastewater.;
It should be noted, however, that caustic-soda-bearing streams cannot be
treated by this process because of the poisonous effects of the caustic on
the IE resin. Also, the IE resin cannot handle sulfides, but since
naturally occurring hydrogen sulfide reacts with mercury and precipitates
prior to introduction to the treatment plant, this limitation is not
expected to be a problem. The process is licensed in the United States
by Crawford and Russel.
1144
The Aktiebolaget Billingsfors-Langed Process. In this Swedish
developed process (Figure 4), which has been in operation for two years,
wastewater is first passed to a vessel where the pH is adjusted to between
5 and 7 and metallic mercury in colloidal form is oxidized by chlorination.
Since the resins subsequently used are sensitive to oxidizers* excess
chlorine is removed in a dechlorinator via acitvated-carbon filtration. The
water is then piped to a series of ion-exchange towers filled with a special,
stable resin, dubbed Q-13. Mercury level is cut to around 100 ppb. No
chloride ions are needed for good performance. The mercury level is reduced
to a few parts per billion in an absorption tower containing another resin,
called Q-Sorb. The Q-13 resin is regenerable, and yields an eluate rich in
mercury. This can be passed to an electrolytic circuit for recovery of the
metal. The Q-Sorb, however, is not regenerable by stripping. Although the
composition of the Q-13 resin is proprietary, it is probable that this is
the same ion-exchange resin described by Fuxelius and prepared from the
reaction of sulfate pulp black liquor and epichlorohydrin.
Option No. 4 - Solvent Extraction. Chapman and Cabah of the University
of Wisconsin have recently developed a solvent extraction process for
removing mercury from liquid or solid mercury-containing wastes, as well as
2062
crushed mercury ore. Mercury content in the feed is first converted
to mercuric chloride, and the pH of the solution is adjusted to less than
3.0 by the addition of excess hydrochloric acid. The liquid waste stream is
then brought into contact with a xylene phase that contains tri-iso-octylamine
(TIOA), so that the mercuric chloride reacts with the amine, thus entering
the xylene phase. The solubilities of both TIOA and TIOA salts in water
32
-------
DECHLORINATOR
Q-13 ION-EXCHANGERS
WASTEWATER
•SULFURIC ACID
•CHLORINE
NEUTRALIZING
TANK
EFFLUENT
(lowppb Hg)
Q-SORB ABSORBER
ELUATE(TO ELECTROLYSIS CIRCUIT FOR RECOVERY OF METALLIC Hg)
Figure 4. The Aktiebolaget Billingsfors-Langed Mercury Removal Process
33
-------
are negligible, and a multistage cduhtercurrent contacting system could be
designed to remove almost all the mercury from the aqueous waste stream.
For example, the mercury level in a depleted brine,originally containing
mercuric chloride in concentrations of about 10 ppm Hg,can be reduced to
10 ppb by extraction with 0.1M TIOA in xylene after only six theoretical
equilibrium stages. With an organic aqueous volume ratio of 0.01, an
organic phase concentration of 1000 micrograms per multiliter mercury is
obtained. In turn, the organic phase can be stripped of nearly all its
mercury cdnteht with a small volume of brine at an equilibrium pH from
9 to 13. Again, this could be accomplished by the addition of endugh
sodium hydroxide to neutralize the hydrochloric acid in amine and bring the
equilibrium pH to the desired villie. By using a high organic to' aqueous
phase volume ratio* a resulting aqueous phase up to 10,000 times more
concentrated in mercury can thus be obtained. Such concentrated solutions
can undergo further processing more easily, both from a technical and
economic viewpoint.
Option No. 5 - Filtration. Diatomite filtration is used to reiriove the
insoluble mercury particulate matter that do not normally settle out by
conventional treatment methods, and has reduced the mercury content of
certain industrial wastes from a high of 5 ppm to less than 0.5 ppm. If
the mercury is solublei the waste stream is first chemically treated to
convert the mercury to an insoluble form, such as elemental mercury^
2048
mercuric oxide, or mercuric sulfide. A more direct approach, however,
is the Ecotech process currently under development that employs a filter
medium of inorganic mineral containing magnesium. Mercury in any ionic
form is directly reduced to elemental mercury in the filter medium by a
replacement reaction, so that removal of soluble inorganic mercury from
wastewater could be accomplished in a single step. Preliminary work at
Ecotech has shown that: (1) for influent mercury concentration of 5 ppm or
less, the removal efficiency in a single pass is typically 85 to 90-percent;
(2) typical filtration rates are 2 to 4 gal per sq ft per min; and (3) a
minimum bed depth of 36 in. is normally required for single-pass treatment.
According to Ecotech, the process is best suited for removing trace
elements of mercury from large volumes of wastewater, such as the paper and
Kraft mill effluents.
34
-------
Option No. 6 - Chemical Absorption. The application of chemical
absorbents for removing mercury from wastewater has been studied by
1145
Environmental Engineering. Laboratory and pilot plant data with a
proprietary absorbent have demonstrated that concentrations of mercury
contaminants can be reduced in minutes from 2,000 ppm to 50 ppb, and even
lower levels may be possible.
Option No. 7 - Adsorption with Activated Carbon. The use of activated
carbon for removing mercury from wastewater has been investigated by Ziegler
and Lafornara, and their experimental results showed that a carbon dose
of 500 ppm could effectively reduce the mercury concentration in water from
100 ppm (as mercuric chloride) to less than 1 ppm. MacMillan proposed a
mercury removal system comprising of a bed of activated carbon sandwiched
between nickel* and mesh pads, and reported that the mercury content of a
mercury cell caustic soda liquor was reduced from 0.8 ppm at the beginning
2082
to 0.1 ppm after passing through the carbon-nickel bed. In both cases,
however, the mercury concentration in the treated effluent is still
considerab1y above the recommended level.
Removal from Solids
For the extraction of mercury from solids or semi-solids such as brine
sludges and mercury catalysts, the general proposed procedure is to use
sodium hypochlorite as the leaching solution. Adequate systems based on
hypochlorite leaching or any other method to treat brine sludges containing
traces of mercury, however, have apparently not been designed and placed
into operation. For example, the brine sludges produced at Georgia-
Pacific's Bellingham, Washington plant are currently being pumped into a
small settling basin awaiting the development and installation of adequate
treatment processes. In addition to hypochlorite leaching, another process
has been recently proposed for the recovery of mercury from brine sludges
or other solids. Yamori et al suggested dissolving the sludge in aqueous
acid and then adsorbing the mercury content of the resultant solution on
*Nickel is wettable by mercury and resistant to attack by caustic soda.
35
-------
an anion exchange resin, from which the mercury can be eluted, preferably
2083
with hydrochloric acid, and recovered from the resultant elute. No
quantitative data, however, was presented to allow evaluation of the process.
To summarize, the adequate methods for removing mercury from gases
are: (1) the Brink mist eliminator or the NAM coalescing filter separator,
with a second-stage unit such as the Farbenfabriken Bayer catalytic system
to remove the last remaining traces; (2) the Union Carbide PuraSiv Hg System;
and (3) scrubbing with sodium hypochlorite solution.
The adequate methods for removing mercury from liquids are: (1) the
Ventron sodium borohydride process; (2) chemical reduction with a granular
zinc bed; (3) the Osaka Soda ion-exchange process; and (4) the Aktiebolaget
Bellingsfors-Langed ion-exchange process. In addition, the Chapman-Caban
solvent extraction process also shows considerable promise as a near future
method for treating mercury containing liquid wastes.
6, APPLICABILITY TO NATIONAL DISPOSAL SITES
Most of the mercury containing wastes generated by the industry, such
as wastewaters from mercury-cell chlor-alkali plants, could best be handled
and treated at the site of generation. There are, however, other types of
mercury wastes where no simple adequate disposal/recovery methods exist,
and these are prime candidate waste streams for National Disposal: brine
sludges, poisoned mercury catalysts, mercury battery cells, mercury
pesticide wastes, mercury paints, and possibly fly ash from coal and other
fossil fuel burning power plants. Methods for the treatment of the mercury
containing wastes at National Disposal Sites will include incineration and
liquid extraction facilities, followed subsequently by recovery/removal of
the mercury from the gas and liquid streams. For the recovery/removal of
mercury from gases, the recommended processes are:
-------
Process Order of Preference Remarks
Union Carbide First choice Demonstrated technology;
PuraSiv Hg system simplicity in operation;
no second-stage unit required
for additional treatment of
effluent.
Demonstrated technology;
insufficient pilot plant
and full scale operating
data for optimal design
of scrubbing system.
For the recovery/removal of mercury from liquids, the recommended processes
are:
Sodium hypochlorite
scrubbing
Second choice
Process
Aktiebolaget
Billingsfors-
Langed ion
exchange process
Ventron sodium
borohydride process
Order of Preference
First choice
Second choice
Remarks
In full scale operation for
two years; ability to treat
wastewaters containing
mercury in any form; ion
exchange resins not poisoned
by caustic or sulfides.
Demonstrated technology; not
critically pH dependent;
requires final polishing
of effluent with activated
carbon or chelating resin;
process applicable to
wastewaters containing
mercury ions rather than
elemental mercury.
37
-------
7. REFERENCES
0096. Fire protection guide on hazardous materials. 4th ed. Boston,
National Fire Association International, 1972. 950 p.
0225. American Conference of Governmental Industrial Hygienists.
Threshold limit values for 1971. Occupational Hazards,
p. 35-40, Aug. 1971.
0278. Code of Federal Regulations. Title 49—transportation, parts 100
to 199. (Revised as of January 1, 1972). Washington, U.S.
Government Printing Office, 1972. 891 p.
0533. Jones, H. R. Mercury pollution control. Rahway, New Jersey,
Noyes Data Corporation, 1972. 250 p.
0637. Stahl, Q. R. comp. Air Pollution aspects of mercury and its
compounds. Report prepared for the National Air Pollution
Control Administration by Litton Systems, Inc., Bethesda,
Maryland under Contract No. PH-22-68-25. Washington, U.S.
Government Printing Office, 1969. 108 p.
0658. Wood, J. M. Environmental pollution by mercury. ^Advances in
environmental science and technology, v.2. Ed. by J. N. Pitts, Jr.
and R. L... Metcalf. New York, Wiley-Interscience, 1971. p. 39-56.
1144. Winning heavy metals from waste streams- Chemical Engineering, 78(9):
62-64, Apr. 19, 1971.
1145. Rosenzweig, M. D. Paring mercury pollution. Chemical Engineering,
78(5): 70-71, Feb. 22, 1971.
1312. Christensen, H. E. ed. Toxic substances annual list 1971. Washington,
U.S. Government Printing Office, 1971. 512 p.
1419. Ziegler, R. C., and J. P. Lafornara. In situ treatment methods for
hazardous materials spills. lr\_ Proceedings; 1972 National Conference
on Control of Hazardous Material Spills, Houston, Mar. 21-23, 1972.
p. 157-171.
1433. Kirk-Othmer encyclopedia of chemical technology. 2d. ed. v. 13.
New York, Interscience Publishers, 1969. p. 218-249.
1570. Weast, R. C. ed. Handbook of chemistry and physics. 51st ed.
Cleveland, the Chemical Rubber Company, 1970.
1673. Perry, R. H., C. H. Chilton, and S. D. Kirkpatrick ed. Perry's
Chemical engineers' handbook. 4th ed. New York, McGray-Hill
Book Company, 1963.
1796. Removal of mercury by ion exchange. Philadelphia, Rohm and Haas
Company, 1972. 3 p.
38
-------
REFERENCES (CONTINUED)
2036. Report of an International Committee: maximum allowable concentrations
of mercury compounds. Archive of Environmental Health. 19 (6):
891-905, Dec. 1969. !
2039. Sneed, M. C., and R. C. Brasted. Comprehensive inorganic chemistry.
v. 4. Princeton, D. Van Nostrahd Company, Inc., 1955. 193 p.
2041. Personal communication. G. Borun, Ecotech Corp., to C. C. Shih,
TRW Systems, May 22, 1972. Mercury removal by filtration -- the
Ecotech process.
2042. Bouveng, H. 0., and P. Ullman. Reduction of mercury in waste waters
from chlorine plants. Jji Proceedings; 24th Industrial Waste
Conference, Purdue University, Lafayette, Indiana, May 6-8, 1969.
p. 969-978.
2045. Gardiner, W. C., and F. Munoz. Mercury removal from waste effluent
via ion exchange. Chemical Engineering, 78(19): 57-59. Aug. 23, 1971
2047. Mist eliminators can recover mercury. Chemical Week, 110(4):50,
Dec. 9, 1970.
2048. Diatomite filter reduces mercury pollution. Chemical Engineering,
77(27):79, Dec. 14, 1970.
2049. Morrison, J. NAM recovers mercury produced with Dutch natural gas.
Oil and Gas Journal. 70(6): 72-73, Apr. 17, 1972.
2050. Logan, W. R. Mercury removal from hydrogen gas streams. Journal
of Applied Chemistry. 16(10): 285-288, Oct. 1966.
o
2051. Chuveleva, E. A..D. P. Nazarov, and K. V. Chmutov. The mechanism of
the sorption of metal ions on carboxylic acid cation exchange
resins IX — the sorption of mercury and calcium on SG-1 resin.
Russian Journal of Physical Chemistry, 44(5): 689-691, May 1970.
2052. Hogfeldt E., and M. Muhammed. Note on ion exchange with mercury (II).
Acta Chemica Scandinavica. 24(7): 2660-2661, July 1970.
2057. Sodium borohydride treatment of chemical process wastes: removal of
mercury. Bulletin no. 28-A. Beverly, Massachusetts, Ventron
Corporation Chemicals Division, 1 p.
2058. Use of sodium borohydride for heavy metal precipitation. Beverly,
Massachusetts, Ventron Corporation Metal Chemicals Division.
2 p. o
2060. The use of zinc to remove mercury from plant waste water. NJZ
technical information bulletin no. 65-557. Bethlehem,
Pennsylvania, New Jersey Zinc Company, May 17, 1971. 4 p.
39
-------
REFERENCES (CONTINUED)
2061. Osaka Soda mercury recovery process. Stamford, Connecticut,
Crawford and Russel Incorporated. 8 p.
2062. Caban, R. Identification and elimination of industrial mercury
pollution. M. S. Thesis, University of Wisconsin, Madison, 1972.
102 p.
2063. Brink, J. A., Jr. Air pollution control with fibre mist eliminators.
The Canadian Journal of Chemical Engineering, 41(3):134-138,
June, 1963.
2064. Parks, G. A., and N. A. Fittinghoff. Mercury extraction now possible
via hypochlorite leaching. Engineering and Mining Journal, 171(6):
107-109, June, 1970.
2065. Manes, M., R. J. Grant, and M. Rocks. Mercury vapor removal. U.S.
Patent.3,193,987, July 13, 1965.
2066. Dreibelbis, J. A., and R. S. Joyce. Method of removing mercury vapor
from gases. U.S. Patent 3,194,629. July 13, 1965.
2067. Park, J. C. and L. 0. Winstrom. Process for reducing the concentration
of mercury in hydrogen gas. U.S. Patent 3,257,776. June 28, 1966.
2068. Manes, M. Silver impregnated carbon. U.S. Patent 3,374,608.
Mar. 26, 1968.
2069. Parks, G. A., and R. E. Baker. Mercury process. U.S. Patent 3*476,552.
Nov. 4, 1969.
2070. Bergeron, G. L., and. C. K. Bon. Process for the recovery of dissolved
mercury salts from brine effluent from mercury cathode electrolytic
cells. U.S. Patent 2,860,952. Nov. 18, 1958.
2071. Neipert, M. P., and C. K. Bon. Recovery of mercury. U.S. Patent
2,885,282. May 5, 1959.
2072. Karpiuk, R. S. and J. J. Hoekstra. Recovery of mercury from brine
containing mercury salts in solution. U.S. Patent 3,029,143.
Apr. 10, 1962.
2073. Karpiuk, R. S. and J. J. Hoekstra. Recovery of mercury from brine
containing mercury salts in solution. U.S. Patent 3,029,144.
Apr. 10, 1962.
o
2074. Gilbert, J. F., and C. N. Rallis. Recovery of mercury from aqueous
solutions. U.S. Patent 3,039,865. June 19, 1962.
40
-------
REFERENCES (CONTINUED)
2075. Calkins, R. C., R. A. Mock, and L. R. Morris. Process for removal
of mercuric ions from electrolytic solutions. U.S. Patent
3,083,079. Mar. 26, 1963.
2076. Scholten, G., and G. E. Prielipp. Mercury recovery and removal.
U.S. Patent 3,085,859. Apr. 16, 1963.
2077. Edwards, G. E., and N. T. LePage. Treatment of brine solutions.
U.S. Patent 3,102,085. Aug. 27, 1963.
2078. Deriaz, M. G. Treatment of brine. U.S. Patent 3,115,389. Dec.
24, 1963.
2079. Grain, E., and R. H. Judice. Electrolytic process for the recovery
of mercury. U.S. Patent 3,213,006. Oct. 19, 1965.
2080. Town, J. W. Method for antimony precipitation of mercury. U.S.
Patent 3,361,559. Jan. 2, 1968.
2081. Rhodes, D. W., and M. W. Wilding. Recovery of mercury from nuclear
fuel processing wastes. U.S. Patent 3,463,635. Aug. 26, 1969.
2082. MacMillan, 0. B. Process and apparatus for removing mercury from
caustic soda solutions. U.S. Patent 3,502,434. Mar. 24, 1970.
2083. Yamori, K., M. Takatoku, A. Miyahara, T. Omagari, and M. Kitamura.
Process for recovering mercury from a mercury containing sludge.
Oct. 27, 1970.
2084. Fuxelius, K. 0. H. Process and a product for the purification of
polluted water from heavy metal ions present therein. U.S. Patent
3,617,563. Nov. 2, 1971.
2085. Williston, S. H., and M. H. Morris. Device for adsorption of mercury
vapor. U.S. Patent 3,232,033. Feb. 1, 1966.
2099. Jensen, S. and A. Jernelov. Biological methylation of mercury in
aquatic organisms. Nature, 223 (5207): 753-754. Aug. 16, 1969.
2100. Joensuu, 0. I. Fossil fuels as a source of mercury pollution.
Science. 172 (3987): 1027-1028, June 4, 1971.
2104. Collins, 0. J., W. C. Miller, and J. E. Philcox. The PuraSiv Hg
process for mercury removal and recovery from vent gas streams.
Paper presented at the 65th annual meeting of the Air Pollution
Control Association. Miami, June, 1972.
41
-------
REFERENCES (CONTINUED)
2105. Wallace, R. A., W. Fulkerson, W. D. Shults, and W. S. Lyon. Mercury
in the environment—the human element. ORNL NSF-EP-1. Oak Ridge,
Tennessee, Oak Ridge National Laboratory, Jan. 1971. 61 p.
2117. U.S. Geological Survey. Geological survey professional paper 713--
mereury in the environment. Washington, U.S. Government Printing
Office, 1970. 67 p.
2172. Mercury in coal need not escape with stack gases as an air pollutant.
Chemical Engineering. 79(14): 54^ June .2.6... 1972.
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercury (257)
IUC Name
Common Names quick silver
Structural Formula
Hg
Molecular Wt. 200.59
(1)
Density (Condensed) 13.594
_ Melting Pt. -38.9 C
@ 20 C(1) Density (gas)
(1)
Boiling Pt. 356.6 C
(1)
Vapor Pressure (recommended 55 C and 20 C)
1.2 X 10~3mm@ 20 C
(1)
Flash Point
1 mm 9 126.2 C
Auto1gn1t1on Temp.
(3)
10 mm
184 C
(3)
Flammabllity Limits In A1r (wt %) Lower_
Explosive Limits in Air (wt. %) Lower
Upper.
Upper_
Solubility
Cold Water 20-30 ppm in deaerated Hot Water
Others:
water
Ethanol
Acid, Base Properties
Highly Reactive with halogens, hydrogen, sulfide. sulfur, vapor
Compatible with_
Shipped in
ICC Classification Poison B
Comments
(2)
Coast Guard Classification
References (1) 2105
(2) 278
43
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Chloride (253)
IUC Name
Common Names corrosive sublimate
Molecular Wt. 271.50^
Structural Formula
HgCl,
Density (Condensed)5.440
Melting Pt. 276 c(1)
_ 9 25 C(1* Density (gas)_
Vapor Pressure (recommended 55 C and 20 C)
1 mm 9 136.2 C(2) 10 mm 9 180.2 C(2)
Flash Point Autoignition Temp.
Flanmabllity Limits in A1r (wt %) Lower
Explosive Limits 1n Air (wt. X) Lower
Boiling Pt._3Q2_dH
100 mm
237 C.
Upper.
Upper_
Solubility
Cold Water 6.9g/100cc at 20 C^ Hot Hater 48q/100cc at 1QO C^thanol soluble^
Others :
Acid* Base Properties
Highly Reactive w1th_
Compatible with
Shipped 1n_
ICC Classification Poison B
(3)
Coast Guard Classification
Comments White crystals or powder. Highly toxic.
References (1) 1570
(2) 1673
(3) 0278
44
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Nitrate (255)
IUC Name
Common Names
Structural Formula
Hg(N03)2-l/2H20
Molecular Wt. 333.61
(1)
Melting Pt. 79 C
.(1)
Density (Condensed) 4.39*'^ 9 Density (gas).
Vapor Pressure (recommended 55 C and 20 C)
Boiling Pt.cjprompncotd)
Flash Point
Autoignition Temp.
Flammabllity Limits In A1r (wt X) Lower.
Explosive Limits in Air (wt. %) Lower
Solubility
Cold Water very soluble'1' Hot Water decomposes*
Others: visible in HN03, NH3> acetone^1^
Acid, Base Properties
Upper_
Upper,
Highly Reactive with alcohols to form explosive irercury fulijrlpatt. with acetylene to form
a sensitive acety fide .and with unsaturates and! aroroatlcs* '
Compatible with_
Shipped in_
ICC Classification
Coast Guard Classification
Comments White yellowish, deliquescent
References (1) 1570
(2) 0096
45
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Nitrate (255)
Structural Formula
IUC Name
Common Names
Hg(N03)2-H20
Molecular kit. 342.61 Melting Pt. • Boiling Pt.
Density (Condensed) 4.3 @ Density (gas) |
Vapor Pressure (recommended 55 C and 20 C)
e 9_ '
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper
Explosive Limits in Air (wt. 55) Lower Upper
Solubility
Cold Water soluble Hot Water Ethanol
Others: soluble in HN03
Acic, Base Properties
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Coast Guard Classification,
Comments Colorless crystal or white powder, deliquescent
References (1) 1570
46
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Sulfate (256)
IUC Name
Common Names
Structural Formula
HgSO,
Molecular Wt. 296.65
Density (Condensed) 6.47
Melting Pt. decomposes Boiling Pt._
Density (gas) 9
Vapor Pressure (recommended 55 C and 20 0
9
Flash Point
Auto1gn1t1on Temp._
Flamiability Limits In Air (wt X) Lower
Explosive Limits 1n A1r (wt. X)
Solubility
Cold Water decomposes
Others: soluble,in acids
Lower
Upper_
Upper
Hot Water
Ethanol insoluble
Acid, Base Properties
Highly Reactive with
Compatible with
Shipped 1n_
ICC Classification Poison B
(2)
Coast Guard Classification Poison B
Comments White, crystalline powder. Highly toxic.
References (1) 1570
(2) 0278
47
-------
HAZARDOUS HASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Pi ammonium Chloride (503)
IUC Name Marcuri c Ch 1 ori de di anrnri ne
Common Names Fusible white precipitate
Structural Formula
Hg(NH3)2Cl2
Molecular Wt. 305.56
Density (Condensed)
Melting Pt. 300 C
Density (gas)_
Boiling Pt..
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp._
Flammability Limits in Air (wt %) Lower
Explosive Limits in Air (wt. %) Lower
Upper_
Upper_
Solubility
Cold Mater insoluble
Others:
Hot Hater decomposes
Ethanol
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Poison B
(2)
Rhombic crystal
Coast Guard Classification
References (1) 1570
(2) 0278
48
-------
PROFILE REPORT
Mercuric Cyanide (254)
1. GENERAL
Mercuric cyanide is one of the most stable of the simple cyanides.
It is formed as colorless or white tetragonal prisms. At 320 C it begins
to decompose and over 400 C it is completely decomposed into mercury and
cyanogen.
Mercuric cyanide is formed when any simple cyanide or ferrocyanide is
1433
heated with a mercuric salt or mercuric oxide.
2KCN + HgCl2 - Hg(CN)2 + 2KC1
2KCN + HgO + H20 + Hg(CN)2 + 2KOH
2K2Fe(CN)5 + 6HgO + 4H20 + 1/2 0£ + 6Hg(CN)2 + 8KOH + Fe203
Mercuric cyanide is used as a substitute for mercuric chloride as
an antiseptic in medicine. Since mercuric cyanide is not ionized, it is
less irritating to the tissues and it does not precipitate proteins or
corrode steel instruments as does the chloride. Dry distillation of
mercuric cyanide is used in the laboratory for the preparation of dry
cyanogen. Patents have been issued, though they are apparently not used,
on the introduction of mercuric cyanide into engine fuels as an "antidetonant"
1433
or antiknock agent.
49
-------
2. TOXICOLOGY
When heated to decomposition, or on contact with acid or acid fumes,
mercuric cyanide emits highly toxic fumes of cyanide and mercury. The
Threshold Limit Value (TLV) for mercury is 0.005 ppm (0.05 mg per cubic
meter of air), as recommended by American Conference of Governmental
Industrial Hygienists (ACGIH); the TLV is 10 ppm (11 mg per cubic meter)
for cyanides. The toxicology for cyanides is documented in Profile Reports
on Hydrocyanic Acid (215) and Hydrogen Cyanide (218). Mercury is a general
protoplasmic poison. After absorption mercury circulates in the blood and
is stored in the liver, kidneys, spleen and bone. In industrial poisoning,
the chief effect is upon the central nervous systems and upon the mouth
and gums. Because mercury has been found concentrated in sea life,
its discharge is avoided.
3. OTHER HAZARDS
When mercuric cyanide is reacted in aqueous solution with mercuric
oxide or chloride, mercuric oxycyanide of varying composition is formed.
The approximate composition of mercuric oxycyanide is 3Hg(CN )2'HgO. The
mercuric oxycyanide is reacted with various acids to form such compounds as
mercuric cyanide nitrate, formate, acetate, oxalate and benzoate. Mercuric
oxycyanide in the dry form is known to explode when being transferred from
one container to another. Therefore, care must be taken not to form mercuric
1433
oxycyanide when mercuric cyanide is being prepared.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Mercuric cyanide is classed by the Department of Transportation (DOT)
as a Class B poison requiring a Poison label. It is shipped in amber
glass bottles, wooden kegs and fiber drums.
50
-------
As with other cyanides, the release of the cyanide ion from mercuric
cyanide must be controlled. The permissible level of cyanide ion in an
effluent stream is 0.2 mg/1 with a desirable criterion of complete absence
(Federal Water Pollution Control Administration [FWPCA]).0536 A goal of
complete absence of mercury from effluents is in effect since the recent
reported mercury buildup in certain fish.
The safe disposal of mercuric cyanide is described in terms of the
recommended provisional limits in the atmosphere, in potable water, and
in marine habitats. These recommended provisional limits are as follows:
Contaminant in
Air
Mercuric Cyanide
Provisional Limits
0.0005 mg/MJ as Hg
Basis for Recommendation
.01 TLV
Contaminant in
Water and Soil
Mercuric Cyanide
Provisional Limits
Basis for Recommendation
0.005 ppm (mg/1) as Hg U.S. Drinking Water
Standard
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
With the goal of no mercury in waste streams, two processes were
recently described that can be used to destroy mercuric cyanide. These
two processes appear equally acceptable and are described briefly in the
following paragraphs.
51
-------
Option No. 1 - Sodium Borohydride Reduction
After alkaline chlorination to destroy the cyanide ion, sodium
1145
borohydride is used.to reduce mercury ions to the metal. This is
accomplished by, adjusting the pH-tp the^S, to 10 range and adding a solution
of sodium borohydride which reduces, mercury to the elemental form and
liberates, hydrogen. The liberated; hydrogen is passed through dilute nitric
acid to remove mercury, vapors. The-mercury is collected by filtering,, and
purified by vacuum distillation:. Sodium borohydride cost is $T3>Op:,Rer Ib,
but one Ib reduces 21 Ibs of mercu.ry.
Option No. 2 - Ion Exchange Collection
After destruction of cyanide by chlorination, mercuric ions are
collected on a special ion exchange resin, Q-13 sold by Aktiebolaget
Billingsfors-Langed of Billingsfors, Sweden. This resin lowers mercury
concentration to the 100 ppb level. Then an absorption tower packed wjth
Q-sorb, sold by the same company a.s Q-13, reduces the mercury content to a-
few parts per billion. The Q-13 resin can be regenerated to recoven- the
mercury, but the Q-sprb resin cannot be regenerated which causes, a storage/
disposal problem that was,not discussed.
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Mercuric cyanide wastes are candidates for disposal at National?
Disposal Sites since the goal of no mercury in waste streams requires
collection of all mercury wastes. It would be expected that concentrated
wastes could be treated commercially as described earlier and;remarketed,
but mixed wastes would require treatment, and storage or burial.
It is recommended that Option No. 1, as described in Section 5 of this
Profile Report, be employed for destruction of mercuric cyanide at National
Disposal Sites.
52
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7. REFERENCES
0536. Water quality criteria. Report of the National Technical Advisory
Committee to the Secretary of Interior. Apr. 1, 1968. Washington,
Federal Water Pollution Control Administration. 234p.
0766. Sax, N. I. Dangerous properties of industrial materials. 2d ed.
New York, Reinhold Publishing Corp., 1957. l,467p.
1144 Pescott, 0. H. Winning heavy metals from waste streams. Chemical
Engineering, 78:62, 1971.
1145. Rosenzweig, M. D. Paring mercury pollution. Chemical Engineering,
78:70-71, 1971.
1433. Kirk-Othmer encyclopedia of chemical technology. 2d ed. 22 v and
suppl.i New York, Interscience Publishers, 1963.
53
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Mercuric Cyanide (254)
IUC Name Mercuric Cyanide
Common Names
Structural Formula
Hg(CN),
Molecular Wt. 252.65
Melting Pt. 320 C decomposes Boil ing Pt. .
Density (Condensed) 4.00 g/cc @ 20 C . Density (gas)_
Vapor Pressure (recommended 55 C and 20 C)
@ @
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) L6wer_
Upper_
Upper
Solubility
Cold Water 9.3g/100ml at 14 C Hot Water 53g/10Qml at 100 C Ethahol soluble
Others: pyridine, acetone, ammonia
Acid, Base Properties
Highly Reactive with mercuric oxide or chloride
Compatible wjth most materials of construction
Shipped in
glass, bottles, wooden kegs, and fiber drums
ICC Classification Class "B" Poison
Commen ts_
Coast Guard Classification Class "B" Poison
References (1) 1433
54
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PROFILE REPORT
Organic Mercury (258 [
1. GENERAL
Introduction
The organic compounds of mercury comprise a diverse group of
materials distinguished by the presence of atoms of mercury joined to
organic molecular structures through chemical bonds. By contrast to the
long history of use of metallic mercury and its inorganic compounds,
organic mercury compounds have been important articles of commerce for a
relatively brief period of time. The development of many of the most
important members of this group of materials was motivated by the need to
find replacements for inorganic mercurials, particularly for agricultural
use, that would provide greater efficiency and lower toxicity to plants,
animals and man.
Although the promise of improved efficiency has been, to a great
extent, fulfilled by the organic mercury compounds, their affect on the
environment has been less salutary. Indeed the tragic incident at
Minamata, Japan, the high levels of mercury found in tuna and swordfish
and the discovery of the facile, biological conversion of mercury and its
compounds to methyl mercury have brought into question the wisdom of any
1951
large scale use of mercury and its inorganic and organic compounds.
Recognition of the extent of the problem of mercury pollution has prompted
a determined effort to define more efficient methods of disposal and con-
trol , and a search for safer substitutes for all current applications of
mercury and mercurials.
2190
Preliminary figures for organic mercury consumption in the United
States in 1971 are: agricultural (includes fungicide and bactericides for
industrial purposes), 1,477 flasks (one flask equals 76 Ib); antifouling
paint, 414 flasks; mildew proofing paint, 8,191 flasks; and pharmaceuti-
cal s, 682 flasks. Total consumption of all mercury and mercury compounds
2190
for 1971 is estimated at more than 52,000 flasks.
55
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Manufacture
1 fil R
Mercury compounds of the aliphatic series Aliphatic mercury com
pounds of the general formula (I) are produced by the reaction of a
dialkylmercury with the appropriate mercury salts:
R2Hg + Hg(Ac)2 -> 2RHgAc
(I)
The dialkylmercury necessary for this synthesis is prepared industrially
by two methods:
(1) Reaction of alky! halides with amalgams of the alkali metals
(most often sodium amalgam):
2RBr + Hg + 2Na + R2Hg + ZNaBr
The process is carried out in the presence of catalysts and at low tem-
peratures.
(2) Reaction of the appropriate organomagnesium compounds with mer-
curic chloride:
R + Mg -> RMg + 2RMgX + HgClg -»• RgHg + MgX2 + MgCl2
A new method for preparing alkylmercury salts by initiated breakdown
of the mercury salts of the carboxylic acids has been suggested by 6. A.
Razuvaev:
(HgOCOCH3)2 -»• CH3HgOCOCH2 + C02
Hydrogen peroxide or inorganic peroxide are used as initiators.
It has also been proposed that ethylmercury salts be prepared from
tetraethyllead and mercuric chloride:
-------
(C2H5)4Pb + 2HgCl2 + (C2H5)
I C1 Q
Mercury compounds of the aromatic series A number of methods are
known for the synthesis of mercury compounds of the aromatic series that
are suitable for industrial production.
One of the principal methods of producing phenylmercury derivatives
is the direct mercuration of benzene which takes place in >90 percent
yield when mercuric acetate or other mercury salts of carboxylic acids are
heated with benzene.
A second method of synthesizing phenylmercury derivatives is the
Nesmeanov reaction, in which the yield of phemymercuric halides amounts to
70 to 85 percent.
Total production of cyclic mercury fungicides for the year 1970 was
)f tha
1718
1,571 x 103 Ib, of that amount, 457 x 103 Ib, or 29 percent, was phenyl-
mercuric acetate.
Uses0533
Agriculture. The primary use of mercury in agriculture has been for
seed treatment of cereal grains (phenyl mercuric acetate, methoxyethyl-
mercury). Secondary uses are for disease control of fruits, vegetables,
etc. Mercurial disease control usage has a long history of successful
application with the added advantage of being relatively inexpensive. The
major commercial applications are with generally mature products vulnera-
ble to being supplanted by newer and/or more effective materials. There-
fore, the opportunities for increased usage and new applications are
either nonexistent or severely limited.
The search for suitable, non-mercurial, substitutes has intensified
in recent years. However, there is general agreement in the industry
that there is not currently available a product affording the broad spec-
trum control provided by mercury compounds.
57
-------
Catalysts. Organic mercurial salts (mercuric acetate, phenylmercuric
oleate) are used in urethane elastomers for casting, sheeting and sealant
applications, frequently as a replacement for stannous octoate catalysts.
The availability of suitable substitutes for organic mercury-based cata-
lysts varies with the particular process under consideration.
Paints. Organomercurial compounds (e.g., phenyl mercuric acetate)
are the most widely used bactericide/fungicide products in the paint indus-
try, accounting for about 80 percent of dollar sales of such protective
paints. Efficiency/cost comparisons with other preservatives invariably
demonstrate the superiority of mercurials in providing both shelf preserva-
tion and exterior protection. However, higher cost non-mercurial substi-
tutes now exist for use in paints and they will probably see increased use
in the future. Most of the currently available substitutes are also
organic metallic (Zn, Pb) and their long-term effect on the environment is
not yet known.
Paper and Pulp. Substantial use of mercury compounds as slimicides
in the pulp and paper industry has continued to decline though they have a
high degree of effectiveness where other types of products have failed.
The decline in use is due to government prohibition of the use of food
packaging paper that have come in contact with mercury compounds and
tighter pollution controls on pulp mill effluent water. The organic mer-
cury slimicides (principally, aliphatic mercurials) are being replaced by
•I /-I o
organotin compounds.
Pharmaceutica 1 s_. Mercury is used in a variety of well defined phar-
maceutical and cosmetic applications. These include diuretics (mercurin),
antiseptics (merthiolate), and preservatives (phenylmercuric acetate).
Substitutes exist for many of the pharmaceutical uses of organic mercury
compounds.
58
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Sources and Types of Organic Mercury Wastes
Organic mercury wastes may arise from the manufacture of pesticides,
Pharmaceuticals, slimicides, explosives and paints, as well as their use in
hospitals, pulp and paper manufacture, farming, home and ship building, and
photographic processing.
Organic mercury wastes can be classified as diluted or concentrated.
Dilute organic mercury wastes include those generated in the waste streams
of manufacturers, and formulators, as well as contaminated formulations
such as pesticides and paints containing small percentages of organic mer-
cury compounds. For example, water based paints usually contain from 0.004
to 0.1 percent mercury in the form of phenyl mercuric acetate, phenyl mercuric
oleate or di (phenyl mercuric) dodecenyl succinate. Total organic mercury
waste generation in the paint industry is estimated to be 34,500 Ib annually.
Concentrated wastes include any unused or contaminated organic mercury com-
pound unfit for its intended use.
Chemical and Physical Properties
The number and diversity of the organic mercury compounds now in use
precludes the preparation of property worksheets for all of them. However,
worksheets have been attached covering the chemical and physical properties
of phenyl mercuric acetate because of its position as the organic mercury
compound with by far the largest sales volume, and of methyl mercury,
believed to be the most widespread and potentially the most dangerous form
of organomercury in the environment.
2. TOXICOLOGY
Organic mercury compounds may enter the body by inhalation, skin
absorption or ingestion.2036 There is evidence that inhalation of organic
59
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mercury vapor and aerosols may be more detrimental than the other means of
entry since absorption through the respiratory tract leads to a higher
rate of accumulation of mercury in the brain.
The tpxicologic effects of organomercurials are strongly influenced
by the nature of the organic portion of the molecule. Short chain alky!
mercury compounds (e.g., methyl and ethyl mercury) are relatively stable
in the body and may circulate for a long time unchanged in the blopd;
?0"%fi
methyl mercury has a biological half-life in man of about 70 days.
The stability of the alky! mercurials, particularly methyl mercury, favors
their accumulation in the body where they are found principally in the
brain. Thus, more than 98 percent of the mercury found in the brain is in
pnoc
the form of methyl mercury.
Aromatic mercury compounds (e.g., phenyl mercury, phenyl mercuric
acetate), methoxyalkyl mercurials (e.g., methoxyethyl mercury) and most
other organic mercury compounds are degraded to inorganic mercury in the
body. Therefore, the physiological and toxicological behavior of the non-
alkyl organomercurials resembles that of inorganic mercury compounds,
with preferential accumulation in the kidneys and more rapid excretion
than the short chain alky! analogs.
Symptoms of methyl and ethyl mercury poisoning may occur weeks to
months after an acute exposure to toxic concentrations. The symptomatology
of acute and chronic poisoning from both compounds is similar; including
numbness and tingling of the lips or hands and feet, ataxia, disturbances
of speech, concentric constriction of the visual fields, impairment of
hearing, and emotional disturbances. With severe intoxication the symp-
toms are irreversible. Children born to mothers with exposure to large
amounts of methyl mercury exhibited mental retardation and also cerebral
palsy with convulsions.
-------
Because so few cases of toxicity have appeared from phenyl mercurials
exposure, even to high levels in air over a period of years, it is apparent
that these compounds are low in toxicity relative to other forms of mercury.
Clinical and experimental evidence suggests that a similar conclusion is
applicable to methoxyethyl compounds.
The Threshold Limit Values (TLV) of 1971 recommended by the American
Conference of Governmental Industrial Hygienists- for alky! mercury compounds
on the skin is 0.01 mg/i
compounds except alkyl.
3 3
on the skin is 0.01 mg/m , and 0.05 mg/m for all forms of organic mercury
3. OTHER HAZARDS
The flammability of organic mercury compounds is governed by the
nature of the organic portion of the molecule and any other materials
(solvents, additives, etc.) with which they are associated in commercial
products. The danger of liberated mercury or mercury compounds must always
be recognized whenever organic mercury compounds are decomposed by heat or
f i re.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT •
Handling, Storage, Transportation :
Since all organic mercury compounds are toxic to man in some degree
by inhalation, ingestion, or skin contact, great care must be exercised in
their handling. Manufacturers instructions for handling and storage
should be closely followed. The use of rubber gloves, goggles, a respirator,
and full protective clothing is recommended in the handling of these
materials over an extended period of time or in large amounts where the
likelihood of exceeding the Threshold Limit Value is present. Shipping of
these materials should be commensurate with existing federal regulations.
61
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Disposal/Reuse
Contaminated, degraded, or surplus organic mercury compounds most
probably will not be considered for reprocessing because of the cloudly
commercial future for these materials. Suspension of government approval
of some products containing alkyl mercury and proceedings to cancel federal
2138
registration of the 750 uses of mercury pesticides might have suffi-
cient impact to shut down production facilities and eliminate the market
for recycled materials. Any method of safe disposal of these materials
must be defined in terms of recommended provisional limits in the environ-
ment. The recommended provisional limits are as follows:
Contaminant Basis of
and Environment Provisional Limits Recommendation
Alkylmercury compounds 0.0001 mg/M 0.01 TLV
in air
Alkylmercury compounds 0.0005 ppm Stokinger and
in water and soil Woodward Method
•s
Other organic mercury 0.0005 mg/M3 0.01 TLV
compounds in air
Other orqanic mercury 0.0025 ppm Stokinger and
compounds in water Woodward Method
and soil
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
pi 97
Option No. 1 - Dilute Aqueous Organic Mercury Wastes
A system for the removal of mercury from plant waste liquors has been
developed by the Ventron Corporation. Waste water containing organic
mercury compounds is treated with chlorine to convert the organic mercury to
inorganic mercury compounds. Then the waste water containing inorganic
mercury compounds is fed, along with a 12 percent solution of NaBH. (in
caustic), into a static mixer. The pH is held between 9 and 11. The NaBH*
reduces the mercury compounds, yielding a metallic mercury precipitate and
hydrogen gas. Following separation of the gas, which is scrubbed with dilute
-------
nitric acid solution to eliminate any mercury vapor, the slurry is passed
to a cyclone. There, 80 to 90 percent of the Hg comes out as a sludge.
Clarified effluent is then sent to polishing filters where the remaining
mercury is removed.
Option No. 2 - Dilute Organic Mercury in Organic Wastes
and Concentrated Organic Mercury Wastes
Organic materials, containing mercury are best disposed of by incinera-
tion with recovery of the metallic mercury using mist eliminators, molecu-
lar sieves, sodium hypochlorite scrubbing, or a combination of the above,
as discussed in detail in the Profile Report on Mercury and Inorganic Mercury
Compounds (p. 23 - 30). Incinerators must be provided with adequate means
of removing other combustion products derived from the organic portion of
the molecules from the gas stream such as chlorine, hydrogen chloride,
sulfur dioxide, NO and other compounds considered to be pollutants.
/\
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
It is anticipated that dilute aqueous organomercury-containing wastes
can be adequately treated at the site of waste generation using Option No.
1 or a similar method. Disposal of dilute and concentrated organic wastes
containing organic mercury compounds may also be handled by manufacturers
and some users at the site of waste generation provided the organization
in question has properly designed and operated incineration facilities.
However, it is likely that many sources of organic mercury-containing wastes
will not be able to support the specialized incineration and recovery faci-
lities needed for their disposal. Therefore, it is recommended that provi-
sion be made at appropriate National Disposal Sites for disposal of organo- '
mercury wastes by some variation of Option No. 2.
-------
7. REFERENCES
0225. Threshold limit values for 1971. Occupational Hazards, Aug. 1971,
p. 35-41.
0278. Code of Federal Regulations, Department of Transportation. National
Archives and Records Service. Title 49, General Services
Administration, 1972 ed.
0533. Jones, H. R. Mercury pollution control. Pollution control review
No. 1. Park Ridge, New Jersey, Noyes Data Corporation, 1971. 251 p.
0637 Stahl, Q. R. Air pollution aspects of mercury and its compounds.
Technical report, Bethesda, Maryland, Litton Systems, Inc.,. •
Sept. 1969. 108 p.
1329. Lutz, 6.A., S. B. Gross, J. B. Boatman, P. J. Moore, and R. L. Darby.
Design of an overview system for evaluating the public health
hazards of chemicals in the environment. Test case studies. VI.
Columbus, Battelle Memorial Institute, July 1967. 157 p.
1570. The Chemical Rubber Company. Handbook of chemistry and physics.
47th ed. Cleveland, 1962. 2,100 p.
1618. Melnikov, W. N. Chemistry of the pesticides. New York, Springer-
Verlag, 1971. 480 p.
1718. United States Tariff Commission. Synthetic organic chemicals.
United States production and sales, 1970. Washington, U.S.
Government Printing Office, 1972. 262 p.
1951. Grant, N. Mercury in man. Environment, 13(4):3-15, May 1971.
2036. Maximum allowable concentration of mercury compounds. Arch.
Environmental Health, 19(6) 891-905, Dec. 1969.
2127. Rosenzweig, M. D. Paring mercury pollution. Chemical Engineering.
78(5):70-71, Feb. 22, 1971.
2138. Pesticides under fire. Chemical Week, (110):14, April 5, 1972.
2190. Personal communication. V. A. Cammarota. United States Bureau of
Mines to W. P. Kendrick, TRW Systems, July 27, 1972.
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name ORGANIC MERCURY COMPOUNDS
Structural Formula
IUC Name
Common Names PHENYL MERCURIC ACETATE
Molecular Wt. 336'75 Melting Pt. 149 c Boiling Pt._
Density (Condensed) @ Density (gas) @
Vapor Pressure (recommended 55 C and 20 0
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility
Cold Water sll'9htl* so1"ble Hot Waters1i9htly s°l^le Ethanol soluble
Others: Soluble in glacial acetic acid, acetic acid, benzene
Acid, Base Properties
Highly Reactive with Dangerous when heated to decomposition
Compatible with_
Shipped in_
ICC Classification Coast Guard Classification
Comments High mammalian toxicityPoral LD$(? for rats 72 mg/Kg
References (1) 1570
(2) 0637
65
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Organic Mercury (258)
IUC Name Dimethyl Mercury
Common Names Methy] Mercury
Structural Formula
Hg(CH,)
3'2
MolecuUr, Wt.
230.66
Melting Pt. "154 c
m -
Density (Condensed) 3.069 @ 20/4 C Density (gas).
Vapor Pressure (recommended 55 C and 20 C)
Boiling Pt.1* 96 C
@
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower •
Explosive Limits in Air (wt. %) Lower
Upper,
Upper_
Solubility
Cold Water
Others:
insoluable
Hot Water
Ethanol
soluble
ether
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification
Comments
Coast Guard Classification
References (1) 1570
-------
PROFILE REPORT
Arsenic Trioxide (51)
1. GENERAL
Arsenic trioxide is a highly toxic, solid compound which occurs as a
waste in a number of industrial and agricultural industries. The starting
material occurs in nature as ores containing various arsenic compounds.
These ores are not mined and processed for their arsenic but rather it is
a major byproduct of the copper, lead, zinc and gold" smelting industries.
Arsenic is present, in small amounts, in most of the ores that are smelted
about the United States, but the ores processed in the Pacific Northwest
produce greater amounts of As^O.,. The ores mined from the Pacific Northwest
area also contain higher amounts of arsenic and in addition, high arsenic
containing foreign ores are smelted there. The copper ores from the Pacific
Northwest contain 2 to 4 percent arsenic and these ores, as well as the
foreign ores, are processed by American Smelting and Refining Company (ASARCO)
in their Tacoma, Washington operations. ASARCO is also the only company
that receives arsenic containing flue dusts (nominally 30 % As^O-) from
other smelters for the refining of arsenic trioxide and its 1970 arsenic
1559
trioxide production was 14,000 tons. These arsenic oxides sublime
off the ore into the flue gas stream and are condensed in a series of
brick condensing chambers called kitchens. The dust emerging from the
kitchens (about 90% As90,) is collected on bag filters or electrostatic
1433
precipitators for purification or sale as crude product. While
awaiting sale and shipment, the arsenic trioxide is stored in large
weatherproof silos at ASARCO's site at Tacoma, Washington. Kennicott
stores their As90~ in railroad hopper cars before shipment to ASARCO for
£ o
metals and arsenic recovery. The demand for arsenic trioxide varies
greatly depending upon the demand for arsenical pesticides whose popularity
appears to be cyclical. The fluctuation in the arsenical pesticide market
-------
is generated by the natural buildup of immunities by agricultural pests to
the compounds which are applied to control them, thus making it necessary
to substitute organics for arsenicals and conversely. At the present time,
it is estimated that there are 40,000,000 Ib arsenic tfioxide in storage at
ASARCO's Tacoma site.
It is recognized that the dry filter bag trapping process and electro-
static precipitators are efficient in removing large dust particles put
a significant amount of small particulates escape into the air. One smel-
ter plant reported its source testing results as 1.1 tons of particulate
emitted per day which contained 34 percent arsenic, 23 percent lead and
smaller amounts of copper and zinc. Phelps Dodge, Kennicott and American
Smelting did not feel it was to their advantage to reveal exact dust
collection efficiencies or emitted flue gas composition and this tends to
indicate that the problem is significant.1549'1550'1565
The major use for arsenic trioxide is in the production of agricultural
pesticides. These include calcium arsenates, arsenic acid, lead arsenate,
sodium arsenate, various arsenites, and organic arsenicals. Arsenic tri-
oxide has often been found as a waste stream constituent in the manufacture
of arsenic pesticides. Examples of waste streams from the pesticide indus-
try include:
3 percent by weight of arsenic trioxide with trace of arsenic acid,
carbon, filter aid, and 80 percent water; and
2 percent by weight of arsenic trioxide, 25 percent filter aid, and
73 percent water.
The lagoon system at Rocky Mountain Arsenal, for example, has been
used over the years by pesticide manufacturers as well as the military for
the discharge of their waste water, and its bottom mud now contains 10 to
100 ppm arsenic (probably mostly in the form of As203)- In addition, there
are also still bottom residues from the production of arsenic fungicides.
The waste amounts to about 16,000 Ib, contains approximately 15 percent
arsenic in various chemical forms, and is currently stored in 55-gal.
drums.
-------
The arsenic pesticides are applied to foliage or to the ground, and
are also used in cattle and sheep dip solutions, as well as being employed
for wood preservatives where nonionic arsenates are fixed in the wood by
means of an autoclave process.
Arsenic trioxide when used in the manufacture of pesticides applied
to plants, such as cotton defoliants, can be expected to occur again as an
arsenic trioxide waste product as a result of burning the pesticide con-
taining foliage. Arsenic trioxide or other arsenic compounds are found
in the dust particles from cotton gins and the trioxide occurs in the
flue gases from the burning of cotton gin trash. The use of bag filters
and electrostatic precipitators is reasonably adequate for arsenic control
from the ginning operation but the burning of the collected trash is not
being adequately controlled. Adverse effects on vegetation in the neigh-
boring areas downwind of cotton gins have been observed and confirmed by
laboratory analysis. About 37 percent of the gins burn their trash
with the remainder returning it to the farm land. Devices are available
for flue gas cooling and particulate collection for cotton trash burning.
They simply require forced implementation by authorities.
The glass industry consumed an estimated 4,100 tons of arsenic
458
trioxide in 1968 for glass processing, friting materials and enamels.
The Drakenfield Co., who is the sales agent of As^O., for ASARCO, reported
sales of 3,000 tons in 1971. Arsenic trioxide is used as a "fining" agent
Purified As^O., is added to molten glass batches in 0.2 percent to 0.75
percent loadings. The As^Og volatilizes and disperses through the glass
batch removing entrained air bubbles while being oxidized to As^Og in the
process. The arsenic remains dispersed in the glass and in the absence of
waste glass slag, there are no significant waste arsenic oxides produced.
Coal contains 0.08 to 16 micrograms of arsenic per gram of coal and
for this reason the air of most large cities contains a small amount of
arsenic, probably as arsenic trioxide. Based upon the range above and a
400 million ton yearly consumption of coal the amount of As203 emitted
69
-------
from coal burning lies somewhere between 300 and 6,400 tons per year. The
3
average 'arsenic concentration in air is estimated to be .020 mg/M . The
maximum urban concentration of arsenic to which one could expect to be
exposed is about 1.4 mg/M .
2. TOXICOLOGY
Human Toxicity
Arsenic trioxide is a powerful poison. The systemic effects are
normally caused by ingestion. As little as 0.1 grams ingested can be fatal
It can also be absorbed by inhalation of the dust. Local contact on the
skin can cause a variety of dermatitis conditions but normally will not
cause systemic symptoms. The acute poisoning symptoms include 'difficulty
in swallowing, severe abdominal pain, vomiting, diarrhea, with pain in the
limbs and muscle cramps, cold damp skin, rapid weak pulse, shock, uncon-
sciousness, convulsions and death. The symptoms caused by chronic low
level arsenic exposure are difficult to diagnose due to the wide variety
of unpredictable symptoms which may arise. The MCA Chemical Safety Data
Sheet SD-60 on arsenic trioxide describes in greater detail the symptoms
of both acute and chronic exposure to arsenic trioxide.
Toxicity Towards Other Plans and Animals
Arsenic trioxide is highly toxic to most forms of animal life.
Previously mentioned damage to plants has been observed but detailed
information on plant effects is not presently available.
3. OTHER HAZARDS
Arsenic trioxide is noncombustible, nonexplosive and as dry solid
is noncorrosive to steel. It dissolves slowly in water to form arsenious
acid at about 2 percent strength which is also highly toxic. It sublimes
at 193 C and as a result the material should be considered a hazard if
heated.
70
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4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage, and Transportation
Because of the highly toxic nature of the arsenic trioxide, special
considerations must be taken to prevent contact with personnel in the
storage, handling, transportation and disposal of this material. Arsenic
trioxide should be stored in areas away from such items as food products
and combustible materials. It should be stored in containers which are
considered "siftproof", that is, mild steel drums, silos or hoppers.
During unloading, emptying or other handling operations, extreme care must
be taken to avoid the generation of dust. Negative pressure pneumatic
transfer equipment is recommended for the loading of hopper cars and
barrels. Adequate exhaust and dust collection equipment is necessary.
Spills of arsenic trioxide should be cleaned up using a vacuum cleaner
or by washing down with a hose to a waste sump after a fine spray of water
has been laid down to prevent dust generation. Arsenic trioxide is classi-
fied by the Department of Transportation (DOT) as a poisonous solid,
Class B. When shipped by rail, water or highway it must comply with all
DOT regulations regarding loading, handling, and labeling. Normal ship-
ping containers are steel drums, and tight wooden barrels, DOT specifica-
tion 10A, 10B or IOC. Hopper or bottom outlet steel railroad cars are
also commonly used. These should be siftproof, self-clearing and equipped
with weatherproof covers. They should not be used for shipping other
material. Each railroad car or individual container must bear the DOT
"Dangerous" placard. All other DOT regulations must be followed.
American Smelting and Refining is currently accepting crude As203 from
the smelting industry on a broad scale. Other smelters collect their flue
dust and ship it to ASARCO for residual metals recovery and As90^ purifi-
£ O
cation. The As203 is stored in weatherproof silos while awaiting sale to
pesticide manufacturers and glass companies. With the possible exception
of ASARCO's own flue dust control which is inadequate but believed to be no
worse than other smelters, the arsenic trioxide handling methods at ASARCO
appear adequate and are a key link In As203 waste management. '
71
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The acceptable criteria for the release of arsenic trioxide into the
environment are defined in terms of the following recommended provisional
limits:
Contaminant in
Air
Arsenic trtoxide
Contaminant i'n
Water and Soil
Arsenic trioxide
Provisional Limit
'0.005 mg/M3 as As
Provisional Limit
Basis for Recommendation
0.01 TLV for As
Basis for Recommendation
0.05 ppm (rng/1) as As Drinking Water Standard
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
Arsenic trioxide is highly toxic and this greatly influences the
types of waste management techniques to be applied at a National Disposal
Site. Especially critical is the problem of reducing the As^O-j emission
to the air from disposal site stacks.
Management of Arsenic Trioxide Wastes
Option No.l - Recycling/Reprocessing. The acceptance by American
Smelting and refining of flue dust from a large part of the other smelting
operations done by other companies is not only adequate but extremely
desirable. They represent a vital key in the adequate handling of ASpO-
waste from sources across the nation. Moreover they are also reclaiming
residual copper, lead, zinc and silver from the dust for significant
credits via a proprietary process. ASARCO charges the other smelting
companies for the treatment of their dust. The value for the recovered
metals is returned to the other smelters. The value received for the
recovered metals exceeds the treatment charge thereby creating a profit
for the firm submitting the dust. The disadvantage of this waste manage-
ment method is that the demand for As203 fluctuates wildly resulting in
frequent large overstocks at the Tacoma, Washington site. Such a con-
dition exists currently and ASARCO is presently reluctantly receiving
outside flue dust. With government subsidies, it is entirely possible
that ASARCO represents a National Disposal Site for all As203 and related
arsenic compounds.
72
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Option No.2 - Land Burial. Under proper conditions of encapsulation
and burial, As90^ and other arsenic compounds might be accepted for dis-
1518
posal by a few selected landfill sites. Lacking enough information
to determine if landfill is adequate, such a decision cannot be presently
made. Two disadvantages are however apparent. It will cost the As?0.,
producer to have the material shipped and landfilled with expectedly ex-
pensive encapsulation. Secondly, for all intents and purposes the material
is unrecoverable. This method should be used only in the event that large
overstocks of As203 are present and long term storage of additional
amounts is not feasible.
Option No.3 - Long Term Storage. Overstocks of arsenic trioxide, as
previously mentioned, are being stored in large weatherproof silos on the
site of ASARCO's plant in Tacoma, Washington. No figures were available
to determine the cost of storing the material. The storage silos are
siftproof and weatherproof and as such they constitute an adequate means
of isolating and containing this poisonous material. Other firms that are
also generating arsenic trioxide as a waste material are also storing this
material in a similar manner by employing railroad hopper cars.
Abatement of ASpO., in Flue Streams
The concentration of As^O., in the flue gases being lost to the air
despite the use of dust removal equipment was not revealed by the firms
contacted, but their refusal to discuss it indicates that the problem is
probably significant. Abatement of AsgOg in gas streams is a current
concern for smelters, cotton gins and other minor As^O^ producers.
Additionally, improvements in dust removal will be an important and
necessary part of any National Disposal Site process design. The follow-
ing dust abatement options would be used after smelting or cotton gin flue
gases were cooled, as required, by passing the flue gases through ASpO,
condensing "kitchens."
Option No.l - Multistage Electrostatic Precipitators. Installation
of electrostatic precipitators is the most common method for As^O, removal.
73
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They are 70 to 90 percent effective and require rapping or flushing of
the grids to remove the dust. The smaller, lighter particles normally
escape entrapment. The types of negative responses received from con-
tacts indicate they are doing a less than adequate job for As90o
precipitation.1549'1550
Option No.2 - Filter/Bag House. Bag house operations are normally
about 99 percent efficient. However, they require 2 to 3 times as much
power as the precipitators. The bags are normally cleaned and dust re-
covered by reversing air flow through them. They are not used as exten-
sively as precipitators and are more costly to acquire. They are
expected to be used more as abatement compliance is required.
Option No.3 - TRW Charged Droplet Scrubber. Charged droplet scrubbers
employ a stream of electrostatically charged water droplets. They are
accelerated through the field between the positive-voltage nozzles and
the negative-voltage collector plates on the side of the flue. In transit,
the droplets collide with dust particles and carry them to the collector
plate where they drain away. Efficiency for a two-stage unit is estimated
to be 99 percent. Size and power requirements are smaller than bag houses
or precipitators. The system is self-flushing and has no moving parts.
The unit is also less expensive to buy or to install.
Option No.4 - Net Vacuum Filtering. There is sketchy information
regarding a chemical plant in the USSR whereby the efficiency of arsenic
removal was greatly improved by using wet vacuum pumps instead of fabric
bag filters. When the fabric filters are used the arsenic content in the
air frequently reached several 100 micrograms per cubic meter. After the
wet scrubbing vacuum pumps were installed, the removal is reported to have
been 100 percent effective. This information is obtained from the Survey
of the USSR Literature on Air Pollution and Related Occupational Diseases
by V. G. Matsak, I960.0634
To summarize, the adequate methods for managing arsenic trioxide wastes
include: (1) shipment to ASARCO for reprocessing; and (2) long term storage
in siftproof and weatherproof containers.
74
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6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Arsenic trioxide is considered as a candidate waste stream constituent
for National Disposal Sites for the following reasons: (1) the material is
highly toxic and nondegradable; (2) the material is present in sizable
quantities as a waste; (3) wastes containing arsenic trioxide are widely
distributed and are contributed by a number of industries; and (4) the
feasibility of the centralized disposal/reprocessing concept has already
been demonstrated by the treatment of one particular type of arsenic
trioxide waste, the flue dusts from copper, zinc, and lead smelters, on
a large scale at ASARCO's Tacoma facility.
For the treatment of arsenic trioxide wastes at a National Disposal
Site, the recommended process is:
Process Order of Preference Remarks
Long Term Storage First Choice Best current method as there
is no demand for As0
An identified need in the reprocessing of arsenic trioxide wastes is
improved flue dust abatement equipment. The residual high level of
arsenic containing dusts in flue gases downstream of currently used dust
removal equipment remains a significant problem in copper, lead and
zinc smelting and arsenic trioxide reprocessing. At present, the use
of fabric bag filters, although not entirely satisfactory, is the preferred
method for controlling airborne arsenic trioxide dusts.
75
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7. REFERENCES
0458. Bureau of Mines. Mineral facts and problems. 1965 ed. Bulletin 630,
1,117 p.
0634. Sullivan, R. J. Air pollution aspects of arsenic and its compounds.
PB-188-070. Bethesda, Maryland, Sept. 1969. 76 p.
1433. Kirk-Othmer encyclopedia of chemical technology. 2d ed. 22 v. and
suppl. New York, Wiley-Interscience Publishers, 1963-1971.
1547. Personal communication. Mr. Loughridge, American Smelting and Refining,
to J. Clausen, TRW Systems, Apr. 18, 1972.
1548. Personal communication. A. Dummkoehler, Puget Sound Air Pollution
Control Board, to J. Clausen, TRW Systems, Apr. 17, 1972.
1549. Personal communication. K. Nelson, American Smelting and Refining,
to J. Clausen, TRW Systems., Apr. 18, 1972.
1557. Manufacturing Chemists Association. Properties and essential information
for safe handling and use of arsenic trioxide. Chemical Safety Data
Sheet SD-60. Washington, 1956. 12 p.
1559. Personal communication. K. Nelson, American Smelting and Refining,
to J. Clausen, TRW Systems, Mar. 3, 1972.
1565. Personal communication. W. Little, Phelps Dodge Corporation, to
J. Clausen, TRW Systems, Apr. 19, 1972.
1566. TRW Systems Group. The charged droplet scrubber. Redondo Beach,
California. 2 p.
1568. Personal communication. J. Stewart, Drakenfeld Company, to J. Clausen,
TRW Systems, Apr. 20, 1972.
1570. Chemical Rubber Company. Handbook of chemistry and physics. 47th ed.
Cleveland, 1966. 1,500 p.
76
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Arsenic trioxide (51)
IUC Name
Common Names White arsenic
Structural Formula
197.82
(1)
As203
Molecular Wt.
Density (Condensed) 3.738 g/cc @
Vapor Pressure (recommended 55 C and 20 C)
,(2)
Melting Pt. sublimes 193 C(2) Boil1ng Pt. 457.2 C(2)
Density (gas)_
1 mm
212 C
10 mm 9 259.T
(2)
Flash Point nonet2' Autoignition Temp.none
Flammability Limits in Air (wt %) Lower Upper,
100 mm @ 332.5
(2)
Explosive Limits in Air (wt. %) Lower none
(2)
Upper_
Solubility p (1)
Cold Water 2.04 g/100 cc at 25 C^Hot Water 11.46 q/100 cc at IQQEthanol so1 •
Others: alkali and HC1
Acid, Base Properties
Highly Reactive with fluorine, hydrogen fluoride
Compatible with steel when dry'2)
Shipped in tight wooden barrels, hopper or bottom outlet steel cars
ICC Classification Poisonous solid. Class B Coast Guard Classification,
Comments Powerful pm'^nn, Tl V fl 5 mn/m a-jy-v*-/ volatils
Need eye, head, respiratory, skin protection
References (1) 1570
(2) 1557
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PROFILE REPORT
Cacodylic Acid (80) and Sodium Cacodylate (382)
1. GENERAL
Cacodylic acid and its sodium salt are poisonous compounds that are
used in agriculture as post emergent, leaf contact, weed killers and
defoliants. The acid is also called dimethylarsinic acid; its formula
being (CH-Jp AsOOH. Either the acid or the salt is used depending on the
pH of the solution used for a specific application. For purposes of this
Profile Report, the two compounds will be referred to as the cacodylates.
These compounds are normally produced and applied as solutions.
2?1 *5
The estimated annual production is about 1,200,000 gal. These
solutions generally contain 2 to 3 Ib of cacodylates per gallon of
solution. The Ansul Chemical Company of Marinette, Wisconsin is
responsible for about 80 percent of the cacodylate production. The
Vineland Chemical Company produces much of the remaining 20 percent.
The cacodylates have EPA registered uses in non-bearing citrus groves,
utility rights of way, ornamental turf control under the trees and shrubs,
and around industrial sites. Recent or soon-to-be-added registrations
include uses in bearing citrus groves and as defoliating agents in cotton
?n?i ??i^
fields. ' Residues from the fallen leaves or material misdirected
to the ground from spraying become tightly bound to soil particles in a
form of irreversible adsorption. Representatives of Ansul Chemical
Company indicated that studies have confirmed no residual plant toxicity
in the soil because these compounds cannot be leached from the soil or
taken up by plant root systems. As an example, they cited the Scott
Lawn products people who, a number of years ago, marketed a cacodylate
base compound which they called "Erase". Erase was applied to ornamental
79
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lawn areas as a contact herbicide, and in three or four days the lawn died.
A new seeding could then be made immediately with no harmful effects on
the new lawn.
Ansul representatives indicated that use of the cacodylates is
heaviest in Texas with smaller amounts being consumed in Arizona and
California. Consumption in the rest of the United States is considered
2215
commercially insignificant.
Manufacture of Cacodylates
The commercial production of cacodylic acid is a 3-step process.
Arsenic trioxide is reacted with sodium hydroxide to yield sodium arsenite.
Methyl chloride is added to produce methanearsonic acid, CH3AsO(OH)2. The
mixture is then reduced with S0? and methylated to recover the dimethylarsinic
op"] c ^
acid. There is no liquid effluent from this process as all the liquid
streams are recycled for reuse. A number of multiple effect evaporators
are employed in the solution recycling systems. The process does, however,
create a solid waste which is a mixture of sodium chloride and sodium
sulfate containing 1 to 1-1/2 percent cacodylate contaminants.
Market Trends for Cacodylate Compounds
Cacodylic acid production was heavier in the early and mid-sixties
when the Army was buying large amounts of it under the general description
of defoliants. It was used extensively in Vietnam for the destruction of
rice fields, now a discontinued practice. Production dropped significantly
when Army purchases ceased but the trend is again toward increased
consumption of the cacodylates because of new EPA registrations for use
of cacodylates on cotton and bearing citrus groves.
Sources and Types of Waste
The major sources of cacodylate wastes are: (1) manufacturers of
cacodylate pesticides; and (2) pesticide residue left in empty containers.
No surplus cacodylate pesticides have been identified.
80
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As indicated previously, solid wastes containing sodium chloride,
sodium sulfate, and 1 to 1.5 percent cacodylate contaminants are generated
in the pesticide production process. The rate at which this waste material
is produced is not known, but at the present time there are 60,000,000 Ib
being stored in concrete vaults in the Marinette, Wisconsin area. There
are currently no plans for the waste material other than to store it
indefinitely.2214
Both cacodylic acid and sodium cacodylate are normally formulated
as liquid solutions. As such, there are usually 0.5 oz to 1 Ib of liquid
residue left in the empty containers, depending on the shapes and sizes of
the containers. The safe and economical disposal of pesticide contaminated
containers remains a serious problem that is still unresolved.
2. TOXICOLOGY
Human Toxicity
Organo-arsenic compounds are highly toxic materials and are very
dangerous even in low concentrations. The American Conference of
Government Hygienists (ACGH) has recommended a Threshold Limit Value (TLV)
npOK
of 0.5 milligrams per cubic meter of air for all arsenic compounds.
This value represents the conditions to which nearly all workers may be
repeatedly exposed on an 8-hr period without adverse effect.
Acute arsenic poisoning from ingestion results in corrosive
irritation of the stomach and intestines with accompanying nausea,
vomiting and diarrhea. In severe cases, collapse and shock can occur
with a weak, rapid pulse, cold sweats, coma or death. The diagnosis of
latent, chronic arsenic poisoning is difficult since the condition
manifests itself with many different and unpredictable symptoms.
Included are disturbances of the digestive tract, liver damage resulting
in jaundice, blood and kidney disturbances and a variety of skin
abnormalities.
81
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Toxicity Towards Plant and Animal Life
Since these compounds are used as herbicides and defoliants, it is
reasonable to believe that they are harmful to terrestial plant life in
general. Arsenic concentrations of 2 to 4 ppm have been found to not
interfere with the self purification of streams, however, fish display
1752
harmful effects at about 15 ppm. It is reasonable to assume that
toxic levels for terrestial animal life are about th,e same as levels
determined for humans.
3. OTHER HAZARDS
The cacodylates do not exhibit any explosive, flammable, or volatile
properties, nor do they present any other hazards.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage, and Transportation
The cacodylate herbicides because of their toxicities require
special consideration for storage, handling, transportation and disposal.
Storage areas for these compounds should be isolated from locations where
food and animal feed are stored. The waste materials should be stored
in the type of containers originally used by the manufacturer. Cacodylate
solutions are packed and shipped by Ansul Chemical Company in 30-gal.
phenolic-lined metal drums, 5-gal. metal pails and 1-gal. high density
polyethylene bottles packed four to a case. Ansul also packs a solid
poi c
product in a polyethylene lined 100-lb fiber drum.
Protective clothing, goggles, gloves and dust filtering respirators
are recommended for unloading or otherwise handling these herbicides.
Similar precautions are recommended for handling any liquid solutions.
Spills of the solid materials should be cleaned up using a vacuum cleaner
after a fine spray of water has been laid down to prevent dust. The
liquid compounds or formulations should be handled in an area such that
'82
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if they are spilled they can be contained for easy cleanup or transfer
to a sump where they will not create a hazard.
The cacodylates are classified as Class B poisons. All Department
of Transportation (DOT) regulations should be followed when shipping,
storing, or otherwise handling the cacodylates.
Disposal/Reuse
The wholesale disposal of these materials into the air, water or
soil must be considered completely unacceptable considering their high
toxicities. The U.S. Public Health Service has established a maximum of
0.05 mg/1 arsenic content (50 ppb) for drinking water if no other drinking
water is available. The ideal maximum is 0.01 mg/1 (10 ppb). The
acceptable criteria for the release of cacodylates into the environment
are defined in terms of the following recommended provisional limits:
Contaminant in Provisional Limit Basis for Recommendation
Air
Cacodylic acid 0.005 mg/M as As 0.01 TLV
Sodium cacodylate 0.005 mg/M as As 0.01 TLV
Contaminant in
Water and Soil Provisional Limit Basis for Recommendation
Cacodylic acid 0.05 ppm (mg/1) as As Drinking Water Standard
Sodium cacodylate 0.05 ppm (mg/1) as As Drinking Water Standard
The cacodylates do not cause soil sterility or adverse plant effects
when found in the soil; nevertheless disposal of them by land spreading is
not recommended because intentional loading of soil with material not
naturally found there is environmentally unacceptable when easier, cheaper
options are available.
There are channels by which unused and unopened containers of
opic
cacodylate compounds can be returned to the manufacturer for resale.
Representatives of Ansul also indicated that they would accept contaminated
or otherwise unwanted material for recycling provided that a process to
remove contaminants was technically and economically feasible.
83
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5. EVALUATION OF WASTE MANAGEMENT PRACTICES
The cacodylates are not expected to occur as waste products in a
reasonably pure or concentrated form. The only identified cacodylate
wastes are the salt by-products from cacodylate manufacturing and
contaminated empty containers. The waste management options for the
cacodylates are presented below.
Option No.l - Recycle/Reuse
Representatives of Ansul Chemical Co. have stipulated the conditions
under which the usable cacodylates can be returned to them for reprocessing
or resale. They will accept unwanted stocks for resale without any
reprocessing if the batch had originally been made by Ansul and if the
materials were in their original unopened containers. This is a completely
adequate waste management technique for these materials if they are in a
concentrated form.
Option No.2 - Long-Term Storage
Storage of cacodylates and cacodylate wastes, until they can be used
or reprocessed, is a satisfactory waste management option. These materials
are stable compounds and require the minimal storage precautions needed
for any toxic material. Storage in the original containers is recommended
but they should be periodically checked for corrosion or breakage of the
containers. Bulk quantities of waste, such as the salt by-products from
cacodylate manufacture, can be stored in concrete vaults or weatherproof
bins.
Option No.3 - Landfill
The disposal of cacodylate wastes in santitary landfills is generally
not acceptable because of the potential danger of ground and surface water
pollution, as well as possible occupational hazards resulting from on-site
handling. There are, however, certain approved sites located over
84
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nonwater-bearing sediments or with only unusable ground water underlying
them and are completely protected from flooding and surface runoff and
drainage such as those designated as Class 1 sites in California. The
disposal of small stocks of cacodylate wastes or empty containers con-
taminated with cacodylates in "Class 1" sites is considered as adequate,
provided special handling techniques as discussed in the previous section
are employed to protect site personnel.
To summarize, the adequate management methods for cacodylate wastes
are: (1) recycle/reuse, (2) long-term storage, and (3) landfill in
"Class 1" sites.
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
The cacodylates are considered as candidate waste stream constituents
for National Disposal Sites for the following reasons: (1) the high degree
of toxicity of the compounds, (2) the nondegradable nature of the toxic
arsenic component of the compounds; (3) cacodylate wastes are present in
sizable quantities as contaminated empty containers; (4) cacodylate wastes
are widely distributed and are often handled by personnel without adequate
training, such as farmers; and (5) facilities for treating other arsenic-
containing materials such as arsenic trioxide, arsenate, arsenite and
other organic arsenical (the mono and di-sodium salts of methane arsonic
acid, commonly called MSMA and DSMA) wastes will be required at National
Disposal Sites.
The processes recommended for the treatment of cacodylate wastes at
National Disposal Sites are:
Order of Preference Remarks
Process
Long-Term
Storage
Landfill
First Choice
Second Choice
Best current method as there is no
market demand for As^O,; a^so re~
commended for the disposal of waste
salt by-product from cacodylate
manufacture.
Disposal sites must meet the criteria
for a California "Class 1" site;
recommended for the disposal of con-
taminated empty containers.
85
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The solid waste salt by-product from cacodylate manufacture contains
sodium chloride, sodium sulfate, and 1 to 1.5 percent cacodylate contami-
nants. The volume of this waste material currently in storage amounts to
60,000,000 Ib. There is a definite need for the development of an
economical process capable of extracting the cacodylate constituents from
the salt waste so that the latter can be readily and safely disposed of
in municipal landfills.
86
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7. REFERENCES
0225. Threshold limit values for 1971. ^Occupational Hazards, Aug. 1971.
p. 35-41.
0766. Sax, N.I., Dangerous properties of industrial materials, 3d ed.
New York, Reinhold Publishing Corporation, 1968. 1,251 p.
1492. The Merck index of chemicals and drugs. 7th ed. Rahway, New Jersey,
Merck & Company, Inc. 1960. 1,643 p.
1570. Weast, R.C., ed. Handbook of chemistry and physics, 48th ed.
Cleveland, Chemical Rubber Company, 1969. 2,100 p.
1752-. Public Health Service drinking water standards. U.S. Department
of Health, Education, and Welfare, Public Health Service,
Publication No. 956, Rockville, Maryland. Environmental Control
Administration. 1962. 61 p.
1784. Frear, D.E.H., Pesticide Index, 3d ed. State College, Pennsylvania,
College Science Publishers, 1965. 295 p.
2021. Burkhalter, T.D., Pesticide uses of arsenic and lead: preliminary
comments. Washington, Environmental Protection Agency, Pesticides
Regulation Division. No date. 8 p.
2173. Lawless, E.W., T.F. Ferguson, A.F. Meiners, A.C. Aspoas, Methods
for disposal of spilled and unused pesticides (Preliminary draft),
Kansas City, Missouri., Midwest Research Institute, Apr. 1972.
271 p.
2214. Personal communication. Bob Gottschalk, Ansul Chemical Company, to
J. F. Clausen, TRW Systems, July 31, 1972.
2215. Personal communication. Frank Wedge, Ansul Chemical Company, to
J. F. Clausen, TRW Systems, July 28, 1972.
87
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Cacodylic Acid (60)
Structural Formula
IUC Name Dimethvlarsjnic acid
Common Names Alkargen (PH } fl^n f
1
Molecular Wt. 138.00 Melting Pt. 200 C Boiling Pt.
Density (Condensed) @ Density (gas) @
Vapor Pressure (recommended 55 C and 20 C)
9 0
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper
Explosive Limits in Air (wt. %} Lower Upper
Solubility
e
Cold Water vecy soluble Hot Water Ethanol very soluble
Others:
Acid, Base Properties
Highly Reactive with
Compatible with
Shipped in
?oo The label
ICC Classification Poison B, poison label. '"Coast Guard Classification Poison R. nniisnn
Cnimwntc essentially non-irritating to skin!2)
rats 1.350 ma/ka(2)
Acute oral LDrn for
References (1) 1570
(2) 1784
88
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Sodium cacodylate (382)
IUC Name Sodium dlmethylarsinatp
Common Names
Structural Formula
5-0 Na • 3H20
Molecular Wt. 314-21
(1)
Density (Condensed)
Melting Pt. -H?0 120 C*
Density (gas)
Boiling Pt._
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper
Upper
Solubility M)
Cold Water 83 g/100 g<2> decomposes^ ^ decomposes(D
Ethanol
Others:
Acid, Base Properties
Highly Reactive with_
Compatible with_
Shipped in
200 lbs(3)
ICC Classification Poison B. poison label. Coast Guard Classification
Comments Relatively non irritating to skin and
Poison label'
R^
References (1) 1570
(2) 1784
(3) 0766
89
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PROFILE REPORT
Calcium Arsenate (87), Copper Arsenate (119), Lead Arsenate (235),
Sodium Arsenate ("376), Zinc Arsenate (453), Manganese Arsenate (500)
1. GENERAL
The arsenates are highly poisonous materials, some of which find
commercial uses in agriculture as pesticides, herbicides, and fungicides.
All six materials have toxic properties but only the calcium and lead
compounds are employed as ingredients in various commercial pesticide
1433
formulations. The remaining arsenates of copper, manganese, sodium
and zinc are not being prepared for agriculture or any other uses in
significant amounts. It is estimated that the consumption for these
other arsenates as laboratory reagents or research curiosities is very
small. ' Therefore, the emphasis of this Profile Report is on
the arsenates of calcium and lead, although the available pertinent
information of the remaining compounds is also presented.
Manufacturing Processes
Industrial awareness for the hazardous properties of the arsenic
compounds has an important influence upon the design of industrial pro-
cesses for the manufacture of arsenic pesticide compounds. Batch pro-
cesses are employed in the production of these materials. The plants
that produce these materials can generally be characterized by their
complete containment of any byproducts or contaminated effluents that
result from these processes. The only liquid effluents from any of
these processes are small amounts of contaminated water from equipment
washout and they are held in evaporating ponds at the plant site.
Water is driven off of the products by means of steam-heated, continuous
drum dryers or spray drying apparatus. Scrubbing equipment treats the
91
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steam effluent from the drying equipment and the scrubbing liquids are
recycled for use as makeup solutions for the next batch. Grinding and
bagging of the products are performed in a closed area with devices to
control the emission of particulates from the operation. Bag filters
are in common use and particulates removed from the bags are packaged
for sale. There is no washing or purifying of the manufactured arsenates
and any aqueous filtrates are recycled for makeup of the next batch.
Calcium Arsenate - Calcium arsenate is a white poisonous material
which is slightly water soluble and is used to control codling moths and
various plant chewing pests. The technical grade product contains a
mixture of the calcium salts of arsenic acid, in which it is believed
the alkaline salt of the composition Ca,(AsOA)9 • Ca(OH)0 predominates.
1742
Other components of the mixture might include CaHAsO.,
Ca3(As04)2 • Ca5H2(As04)4, CaC03 and some unreacted Ca(OH)2.
Calcium arsenate is made from reacting arsenic acid or its salts with
calcium hydroxide:
(1) Reaction of water soluble salts of arsenic acid with lime.
Na3As04 + 4 CaOH2 + Ca3(As04)2 • Ca(OH)2 + 6 NaOH
(2) Reaction of arsenic acid with lime.
2H3As04 + 4 Ca(OH)2 -> Ca3(As04)2 • Ca(OH)2 + 6H20
The product is applied both as a dust and as a sprayable aqueous suspension.
It is incorporated in baits for the control of worms, snails and slugs for
tree and vegetable crops. It is also used as a selective herbicide
1728
on ornamental lawns.
Calcium arsenate has certain undesirable properties that have limited
its general use on most plants. Unless applied with an excess of lime,
serious plant damage may result from application on certain crops. Calcium
92
-------
arsenate is also easily decomposed after application to plant surfaces.
Hydrolysis of the calcium arsenate takes place in aqueous suspension and
results in the formation of calcium hydroxide and arsenic acid. However,
calcium arsenate still finds use as a dust since it is simple to produce
the material in a form suitable for dusting on certain plants that are
less susceptible to damage. Approximately 2 million Ib were consumed
in 1969 (little change from 1968).1738
Lead Arsenates - There are many mixtures of lead and arsenic that
are commonly called lead arsenates. The chemistry of these various
1742
combinations have been exhaustively investigated, and only two lead
arsenates have the physical properties and chemistry which makes them
useful as pesticides. Standard lead and basic lead arsenate are the two
which will be discussed. The other lead arsenate compounds are apparently
found only in the laboratory, if at all. During manufacture, purification
of these pesticides is not performed, and they are sold as mixtures of
reactants and various products.
Dilead ortho arsenate, PbHAsO., is commonly called acid lead arsenate
and is also known as dibasic lead arsenate, diblumbic hydrogen arsenate,
hydrogen arsenate and others. As a pesticide it is called standard lead
arsenate, the name to be used in this report. Standard lead arsenate is
prepared on a commercial scale by the combination of arsenic trioxide,
nitric acid and litharge.
The other lead arsenate used in pesticides is commonly called basic
lead arsenate. Various formulas have been suggested for the series of
compounds including Pb4(PbOH) • (As04)3 • H20 and Pb5(PbOH)2 • (AsO.). but
it is difficult to determine which of the above or any other is correct.
Undoubtedly, several compounds exist in the commercial preparations that
are called basic lead arsenates. It is also apparent that a whole range
of compositions is possible depending upon the composition of the reactants
as well as time and temperature parameters for each particular preparation.
93
-------
The lead arsenates are applied to fight various worms, moths and
other foliage-destroying insects that occur on fruit trees, grapes, walnuts,
grapefruit and oak trees. The 1969 consumption (or domestic disappearance)
of lead arsenate was estimated to be 7.7 million Ib, which was an increase
over the 1968 consumption of 4.7 million Ib. The consumption of lead
arsenate since 1969 has been generally decreasing and in the spring of 1972
the EPA has lifted the registration which permitted the use of lead arsenate
compounds. This effectively will cause the decline of lead arsenate use
to the point where it will be insignificant in the future.
Other Arsenate Compounds - The remaining arsenate compounds included
in the Profile Report, while having approximately the same toxic properties
as those of lead and calcium, are not currently being used as pesticides in
the United States. This section will therefore be confined to the dis-
t
cussion of the limited available information concerning these arsenic
compounds.
Copper arsenate [Cu(CuOH)AsO.] is a very stable crystalline material
that is not easily hydrolyzed by water. This basic copper arsenate is
believed to be as toxic as lead arsenate when used as an insecticide. The
three current arsenate manufacturers were not aware of any copper arsenate
being produced or used in the United States since Sherwin-Williams closed
down their plant. The commercial product covered by the patents is pre-
pared from arsenic acid, copper sulfate and lime. The calcium sulfate in
the reaction product is not removed and the final mixture contains 41 to
46 percent of the basic copper arsenate.
Manganese arsenates have been prepared for research purposes and
have been found to have some merit as insecticides although they have
been determined to be less effective than lead arsenate. It appears to
have a very high toxic effect on plants and this reduces its appeal as
an effective insecticide.
94
-------
The basic salt of zinc arsenate is reported to have the approximate
composition: 5 ZnO • 2 As05 • 4H20. Its toxicity is similar to that of
calcium arsenate and the Pesticide Index has indicated its use as an
1784
insecticide.
(i
Sodium arsenate appears to be the common name for disodium arsenate
(Na2HAs04 or Na2HAS04 • 7H20). It is a solid which is freely soluble in
water and glycerol. It is considered to be highly poisonous. It has
been used in the past as an insecticide and a herbicide.
Physical Properties of the Arsenate Compounds - In trying to obtain
information of the physical properties of these arsenate compounds, it
has become clear that the common name calcium arsenate, lead arsenate,
etc., applies to a rather large host of different arsenic/metal compounds.
The differences between these compounds involve different oxidation states
of the various arsenic and metal ions as well as waters of hydration and
crystal structure. It must also be remembered that many of these compounds
are still being debated as to their actual structure. In light of this,
some of the data which would normally be found on the hazardous properties
worksheets are not presented on the worksheets in this profile report.
Market Trends for Arsenates - The inorganic arsenate market has been
in broad decline in recent years, as a result of the strict government
controls placed on the use of arsenical pesticides. These materials are
highly poisonous in all forms and prolonged application of them in agri-
culture have caused a serious buildup of these materials in the soil.
The point has been reached in some areas where the arsenic pesticides or
their hydro!yzed products have become so concentrated in the soil that
they have made it almost unsuitable for growing anything. Some orchards
have had the top 3 ft of soil replaced. There also is the threat
of large amounts of arsenic being leached out of the soil into streams
and rivers thus causing serious damages to the aquatic life.
95
-------
The consumption of lead and calcium arsenate compounds for 1969 was
estimated to be approximately 10 million Ib. This is in sharp contrast
to the production of over 100 million Ib several years ago. The number
of companiescthat are producing arsenate compounds have also decreased.
Only three exist today for the manufacture of calcium arsenate and lead
arsenate. They are Chevron Chemical Company, Niagara Chemical Company,
and Los Angeles Chemical Company.
Sources and Types of Wastes
As indicated previously, arsenic pesticide manufacturers are generally
characterized by their complete containment of any byproducts or contami-
nated effluents that result from the production processes. The three major
sources of arsenate wastes are therefore: (1) pesticide residue left in
empty containers; (2) surplus pesticides stored in Department of Defense
(DOD) and state/municipal facilities, Environmental Protection Agency (EPA)
regional offices, and formulating plants; and (3) soil contaminated with
high levels of arsenates from the repeated use of the pesticides.
Arsenate pesticides are usually formulated as dusts, granules, or
wettable powders and packed in siftproof, multiwall paper bags. The amount
of pesticide residue left in the containers is therefore considerably less
than those for liquid pesticide formulations, and the disposal of arsenate
contaminated paper bags also poses a lesser problem than the disposal of
liquid pesticide containers such as glass bottles and steel drums.
Surplus arsenate pesticides currently in storage awaiting disposal
include the following:
(1) DOD - 1,624 Ib of 98 percent lead arsenate in Texas,
and 12 Ib of 98 percent lead arsenate in Michigan.
(2) State/EPA - 96 Ib of 95 percent lead arsenate and 305 Ib
of 70 percent calcium arsenate in Washington, and
2,460 units of arsenate containing Harris Ant
Buttons in Georgia.
(3) Pesticide manufacturers - an estimated 24,000 Ib of lead
arsenate at South Gate, California.
-------
The extensive use of arsenic pesticides in the past, particularly
lead arsenate, has led to soil sterilization and rendered large acreages
of farm land unusable for the growth of future crops.
2. TOXICOLOGY
Human Toxicity
The arsenate compounds are highly toxic materials and are dangerous
even in very low concentrations. The American Conference of Governmental
Industrial Hygienists (ACGIH) has recommended a Threshold Limit Value (TLV)
3
of 0.5 mg/M for all arsenic compounds. This value represents the condition
to which nearly all workers may be repeatedly exposed without adverse effect.
Acute arsenic poisoning from ingestion results in irritation of the
stomach and intestines with accompanying nausea, vomiting and diarrhea.
In severe cases, collapse and shock with a weak, rapid pulse, cold sweats,
coma or death can occur. The diagnosis of latent chronic arsenic poisoning
is difficult since the condition may manifest itself with many different
and unpredictable symptoms. Included are disturbances of the digestive
tract, liver damage resulting in jaundice, blood and kidney disturbances
and a variety of skin abnormalities.
Toxicity Towards Plant and Animal Life - Each of the arsenates has a
somewhat different effect on either plant or animal life. Some of the
compounds, calcium arsenate or lead arsenate, can be applied to certain
vegetable and fruit foliage without adverse effect, although all the
compounds should generally be considered as being toxic to some plant
life. The extreme toxicity of these compounds towards human life can
be considered the same for animal life as well. All precautions must be
taken to prevent run-off from farms and orchards into streams and rivers
where the arsenate compounds can adversely affect aquatic plant and
animal life.
97
-------
1
Emphasis has thus far been placed on the arsenic constituents of the
arsenate compounds being discussed but it should not be forgotten that
some of the cations involved in the arsenate compounds also have toxic
properties, the compounds of copper and lead under general conditions
are also very hazardous. The Threshold Limit Values (TLV's) of these
•5 0225
materials are also 1 nig/M and belov^ Therefore, the toxicity of
these cations should be at least considered in the scope of this Profile
Report inasmuch as they are themselves hazardous.
3. OTHER HAZARDS
The arsenates do not exhibit any explosive or flammable properties
nor do they present any other hazards.
4. DEFINTION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage and Transportation
The arsenate pesticides require special consideration in their storage,
handling, transportation and disposal. Storage areas for these compounds
should be isolated from locations where food and animal feed is stored.
Calcium and lead arsenate should be stored in siftproof, multiwall paper
bags originally supplied by the manufacturer. The use of protective
clothing, goggles, gloves and dust filtering respirators are recommended
for unloading or otherwise handling these pesticides. Similar precautions
are recommended for handling any liquid solutions. Spills of the solid
materials should be cleaned up using a vacuum cleaner after a fine spray
of water has been laid down to prevent dust. The liquid compounds or
formulations should be handled in an area such that if they are spilled
they can be contained for easy cleanup or at least will not create a
hazard if they are absorbed by the ground.
98
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Although only some of the arsenical compounds are labeled as
Class B poisons by the Department of Transportation (DOT), it is recom-
mended to treat the others in the same manner. All other DOT regulations
should be followed when shipping, storing or otherwise handling arsenate
compounds.
Disposal/Reuse
The wholesale disposal of arsenate compounds into the air, water, or
soil must be considered completely unacceptable considering their high
toxicities. The U. S. Public Health Service has established a maximum
of 0.05 mg/1 arsenic content (50 ppb) for drinking water, if no other
1 7*5?
drinking water is available. The ideal maximum is 0.01 mg/1 (10 ppb).
The disposal of these materials is ironically a moot point since it is the
air, water and soil where the arsenic pesticides ultimately end up in
normal cases. The lead and calcium arsenates after application to plant
surfaces, find their way to the ground when the plant drops its leaves or
when rainfall washes them from the plant onto the ground. In a practical
sense, this is where the real waste problem with the arsenates lies. The
pesticides then reside in the soil where they are not easily removed
except by the equally undesirable process of leaching and runoff into
nearby streams and lakes. In some cases, small overstocks of these
pesticides have been spread out on farm land for disposal much in the
same manner as when they are applied to crops. The rather weak rationale
for this is that the soil is already contaminated with these materials
and the addition of a small increment would not make any difference. In
another case, it might be applied to farm land, where arsenical pesticide
application has never been used, with the reasoning that a small amount
in the soil would cause no significant effect. However, it should be
emphasized that the buildup of arsenic compounds in the soil has created
the problem of soil sterilization and the inability of any type of plant
to grow. It is, of course, this very problem of arsenic compound buildup
within the soil that is causing the Environmental Protection Agency to
strongly regulate against the use of these compounds.
99
-------
The acceptable criteria for the release of arsenate compounds into
the environment are defined in terms ,of the following recommended pro-
visional limits:
Contaminant in
Air
Calcium arsenate
Copper arsenate
Lead arsenate
Sodi urn arsenate .
Zinc arsenate
Manganese arsenate
Contaminant in
Water and Soil
Calcium arsenate
Copper arsenate
Lead arsenate
Sodium arsenate
Zinc arsenate
Manganese arsenate
Provisional Limit
0.005 mg/M-, as As
0.005 ipg/M/, as As
. - •.,... -
0.005 mg/M , as As
0.005 mg/M , as As
0.005 mg/M , as As
0.005 mg/M3, as As
Provisional Limit
Basis for Recommendation
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
Basis for Recommendation
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
There are channels by which unused and unopened containers of the
arsenate pesticides can be returned to the manufacturer for resale.
Representatives of the manufacturers also indicate that they would accept
contaminated or otherwise unwanted arsenate pesticides for reprocessing
provided that the process was technically and economically feasible.
However, the great amounts of waste arsenate compounds are of course in
the soil and a scheme by which these compounds could be recovered from the
soil, reprocessed and recycled into other products while being environ-
mentally desirable would in all likelihood be economically infeasible.
100
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5. EVALUATION OF WASTE MANAGEMENT PRACTICES
There are five waste management methods which have applicability to
the arsenate compounds and which are currently being used or which might
be applied at a National Disposal Site. It should be stressed that regard-
less of the type of waste treatment process employed, it still would be
necessary to deal with toxic arsenic in some form. The following is a
discussion of the options for the management of arsenate pesticides.
Option No. 1 - Recycle/Reuse
Representatives of the three remaining manufacturers of arsenic
pesticides have described the conditions under which these materials were
returned to them for reprocessing or resale in the past. Each firm
accepted these arsenate materials for resale without any reprocessing
if the batch had originally been made by the firm and if the materials
were in their original, unopened containers. Each firm expressed its
reluctance to accept the product of other firms. Given the hypothetical
situation of a batch of materials which had been contaminated with a
material that can be easily removable by means of processing, each firm
indicated its willingness to accept it for reprocessing provided that
there was an available market for the material.1555'1711'1712 In light
of the recent EPA order lifting the registration of standard lead and
basic lead arsenate pesticides, it is expected that these three firms
will have a problem in disposing of current stocks and would not accept
any return of the lead arsenate products. It was stated that in some
situations, unwanted pesticides are being returned to the supplier in
spite of the supplier's refusal to accept them. The users have been known
to leave sacks of unwanted products at the supplier's loading dock after
closing hours. Such an approach can be viewed positively insofar as it
places the disposal problem on someone who at least has some facilities
for safe handling of the material.
101
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Option No. 2 - Long Term Storage
The use of large, weatherproof and snftproof storage bins or silos is
currently being used for the storage of other arsenic compounds, especially
arsenic trioxide. Waste pesticides already packed in multiwall paper
bags could also be safely stored in these large weatherproof bins. This
approach is relatively expensive. Land and storage equipment are
required for long, unknown period of time before these materials
can be moved by sale or disposal to other outlets. Considering the fact
that these arsenic compounds are poisonous in all forms, the technique of
long term storage has to be considered as adequate and currently practical.
Option No. 3 - Land Spreading
Some users, when faced with unwanted stocks of some of these pesticides,
use land spreading as a means of disposal. This approach involves spreading
the waste materials over large amounts of land in very light applications
so as not to significantly affect any of the crops or plant life growing
in the vicinity. The technique might be used for rare or infrequent
disposal of small amounts of the material but in light of the fact that
these compounds will build up in the soil by repeated application, this
method cannot be considered as completely adequate and other methods should
be considered first.
Option No.4 - Export
Some foreign countries are still using arsenate pesticides where possi-
ble contamination has not become a critical issue as in the United States.
The prospect of selling unwanted stocks of the arsenate pesticides to
1712
neighboring countries, especially Mexico, is being actively considered.
It is conceivable that many foreign countries might have a specific need
for a number of these arsenate pesticides where their use would not create
a critical problem. However, although the export of unwanted arsenate
pesticides from the United States can be considered as desirable from the
viewpoint of solving the domestic disposal problem, the long term effects
are the probable global arsenic pollution of the environment.
-------
Option No. 5 - Process for Recovery of Metals in Arsenates
American Smelting and Refining (ASARCO) has a process operating at
its Tacoma, Washington plant whereby they are recovering lead, copper, zinc,
and possible other metals from smelter flue dust which contains large
amounts of arsenic trioxide. The details of the process are proprietary
to ASARCO but it is conceivable that this basic process might be employed
to recover lead, zinc and copper from the arsenate pesticides as well.
However, it should be remembered that this process would still result in
the production of arsenic trioxide which is a disposal problem in its own
right.1547
Option No. 6 - Landfill
The disposal of arsenate compounds in sanitary landfills is generally
not acceptable because of the potential danger of ground and surface water
pollution as well as possible occupational hazards resulting from on-site
handling. There are, however, certain approved sites located over nonwater
bearing sediments or with only unusable ground water underlying them and
are completely protected from flooding and surface run-off or drainage such
as those designated as Class 1 sites in California. The disposal of small
stocks of arsenate pesticides or empty containers used to ship arsenate
particles in "Class 1" sites is considered as adequate, provided special
handling techniques as discussed in the previous section are employed to
protect rite personnel.
To summarizes the adequate management methods for arsenate wastes
are: (1) recycle/reuse; (2) long term storage; (3) ship to ASARCO for
recovery of the metal values and long term storage of arsenic trioxide;
and (4) landfill in "Class 1" sites.
-------
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Arsenates are considered as candidate waste stream constituents for
National Disposal Sites for the following reasons: (1) the high degree of
toxicity of the compounds; (2) the nondegradable nature of the toxic
arsenic component of the compounds; (3) arsenate wastes are present in
sizable quantities as contaminated bags and empty containers, surplus
pesticides, and contaminated soils; (4) arsenate wastes are widely
distributed and are often handled by personnel without adequate training
such as farmers; and (5) facilities for treating other arsenic-containing
materials such as arsenic trioxide, arsenite and organic arsenical wastes
will be required at National Disposal Sites.
The processes recommended for the treatment of arsenate wastes at
National Disposal Sites are:
Process Order of Preference Remarks
Long term storage First Choice Best current method as there is
no market demand for As203
Landfill Second Choice Disposal site must meet the
criteria for a California
"Class 1" site; recommended
for the disposal of contami-
nated bags and containers.
Decontamination of soils containing high levels of arsenates as the
result of repeated applications has been identified as a problem area.
At the present time there does not appear to be a simple and economically
feasible method available to render large acreages of arsenic poisoned
farm land reusable for the growth of crops.
-------
7. REFERENCES
0225. American Conference of Government Industrial Hygienists. Threshold
limits for 1971. Occupational Hazards, Aug. 1971. p. 35-40.
0766. Sax, N. I. Dangerous properties of industrial materials. 3d ed.
New York, Reinhold Publishing Company, 1968. 1,251 p.
1492. Merck and Company, Inc. The Merck index of chemicals and drugs.
Rahways New Jersey, 1960. 1,643 p.
1547. Personal communication. Mr. Loughridge, American Smelting and
Refining, to J. Clausen, TRW Systems, Apr. 18, 1972.
1555. Personal communication. H. Fisher, Chevron Chemical Company, to
J. Clausen, TRW Systems, Mar. 7, 1972.
1570. Chemical Rubber Company. Handbook of chemistry and physics. 47th ed.
Cleveland, 1966. 1,500 p.
1708. Personal communication. Mr. Stellmacher, Niagara Chemical Company,
to J. Clausen, TRW Systems, May 11, 1972.
1711. Personal communication. Dr. W. Wade, Niagara Chemical Company, to
J. Clausen, TRW Systems, May 11, 19/2.
1712. Personal communication. H. Stevens, Los Angeles Chemical Company,
to J. Clausen, TRW Systems, May 12, 1972.
1715. Personal communication. L. Fowler, U. S. Department of Agriculture,
to J. Clausen, TRW Systems, May 12, 1972.
1716. Personal communication. Dr. D. Frear, Pennsylvania State College
Pesticide Research Center, to J. Clausen, TRW Systems, May 11, 1972.
1728. Los Angeles Chemical Company. Data sheets and container labels for
arsenic pesticides.
1738. U. S. Department of Agriculture. The pesticide review. Washington,
1970.
1740. Personal communication. D. B. Barem, Chevron Chemical Company, to
J. Clausen, TRW Systems Group, May 12, 1972.
1742. Frear, D. Chemistry of insecticides, fungicides, and herbicides.
2d ed. New York, D. Van Nostrand Company, 1948. 417 p.
1752. Public Health Service. Public health service drinking water standards,
Publication No. 956. Rockville, Maryland, 1962. 61 p.
1784. Frear, D. Pesticide index. 3d ed. State College, Pennsylvania,
College Science Publishers, 1965. 252 p.
-------
. .^^'".^•^^•».J-^,.pl|rffly^T,H.rT^^ tmmjc,i ICC Classification Poison B Coast Guard Classificati
1 Comments white, amorphous powder
i
on Poison B
'
.
! '•
References (1) 0766 i
(2) 1570
f
U ... .... i~».i i.-i..--»J.i--- -'JJlk».»'i«JM!iJtM,JvV>'JAj..;au>jJfatJMUif.lyJ-lil.*."]eA«t, ^^.akJ,tL^i.^VvM,^.lJM,AVir^.JA-.tat!g-lHM'Jilltlli.[jia-'UaJ»1.L.«^ ,tuJ,-. ulfL
106
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name copper arsenate (119)
IUC Name copper II orthoarsenate^ '
Common Names
Structural Formula
Cu3(As04)2 • 4H20
Molecular Wt. 540.52
(1)
Melting Pt.
Density (Condensed) @
Vapor Pressure (recommended 55 C and 20 C)
Density (gas)_
Boiling Pt.
G>
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper_
Upper_
Solubility
Cold Water insoluble'1^
Hot Water insoluble
(V
Ethanol
Others:acids. NH^OH
Acid, Base Properties^
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification
Comments
Coast Guard Classification
References (1) 1570
107
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name copper arsenate (119)
IUC Name copper II dihydrogen ortho arsenate
Common Names
(1)
Structural Formula
Cu5H2(As04)4-2H20
Molecular Wt. 911.42
(1)
Melting Pt.
Density (Condensed)_
Density (gas)_
Boiling Pt._
G>
Vapor Pressure (recommended 55 C and 20 C)
0 @
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper_
Upper_
Solubility
Cold Water insoluble^
Others : sol, in acids, NH^OH
Acid, Base Properties
Hot Water
Ethanol
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification^
Comments
Coast Guard Classification
References (1) 1570
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
ti. M. Name Lead arsenate (235)
Structural Formula
IUC Name
(3)
Common Names acid lead arsenate^ ' dibasic lead
arsenate, lead hydrogen arsenate
,0)
PbHAsO,
.(1)
Molecular Wt. 347.2V" Melting Pt. d. 720 C" Boiling Pt._
Density (Condensed) 5.79 g/cc^ ' @ Density (gas) @
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper_
Upper
Solubility
Cold Water insoluble
Hot Water slightly soluble^" Ethanol
Others: sol. HMO.,, caustic
Acid, Base Properties
(T)
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification_
Commen ts
Coast Guard Classification
References (1)
109
-------
HAZARDOUS WASTES PROPERTIES
'WORKSHEET
H. M. Name lead arsenate (235)
Structural Formula
IUC Name
Common Names basic lead arsenate
Pb4(PbOH)(As04).
*
Molecular Wt. . Melting Ft. Boiling Pt._
Density (Condensed) & ' Density (gas) @
Vapor Pressure (recommended 55 C and 20 C)
9 & (
Flash Point Autoignition Temp._
Flammability Limits in Air (wt %) Lower Upper
Explosive Limits in Air (wt. %) Lower Upper
Solubility
Cold Water Hot Water Ethanol,
Others:
Acid, Base Properties
Highly Reactive with_
Compatible with_
Shipped in Multiwall paper bags
ICC Classification Poison Class B Coast Guard Classification
Comments identified as the probable commercial basic lead arsenate^1'
No physical properties available for this complex compound since it occurs as a
mixture of various PbQ/AsJ)- ratios.
References (1) 1742
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Sodium Arsenate (376)
^ Structural Formula
IUC Name
Common Names
Na2HAs04.7H20
Molecular Wt.1 ^-Q1 (1) Melting Pt.2 125 C (1) Boiling Pt. "7 H2° at 100C
Density (Condensed) 1.871g/cct k __ Density (gas) _
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
• H. H. Name Zinc arsenate (453)
Structure
IUC Name
Common Names zinc o-arsenate Koettigite Zn^AsO^) • 8
1 F/tk*mn1 a
H2o !
Molecular Wt. 618.09 Melting Pt. H?° at ^"C Boiling Pt. '
Density (Condensed) 3.309 @ 15 ' C(2^ Density (gas) @ "\
\ Vapor Pressure (recommended 55 C and 20 C)
; (a @
i Flash Point Autoignition Temp.
9
1 Flammability Limits in Air (wt %) Lower Upper 1
= Explosive Limits in Air (wt. %) Lower Upper i
Solubility
Cold Water insoluble(2) Hot Water insoluble*2^ Ethanol
Others: H-AsO,, H-PO,,, alk(2J
Acid, Base Properties
Highly Reactive with
;
Compatible with
Shipped in
ICC Classification Coast Guard Classification
Comments
;
!
References (1) 0766
(2) 1570
1 - - • . ^ ,..^u*.«.
112
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Manganese Arsenate (500)
Structural Formula
IUC Name
Common Names
MnHAsO
4
Molecular Wt. 194.9^ Melting Pt. Boiling Pt._
Density (Condensed) @ Density (gas) @
Vapor Pressure (recommended 55 C and 20 C)
(P > @ C
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper
Explosive Limits in Air (wt. %) Lower Upper
Solubility
Cold Water Slightly soluble Hot Water Ethanol
Others: Soluble in acids
Acid, Base Properties
Highly Reactive with
Compatible with
Shipped in_
ICC Classification . Coast Guard Classification_
Comments Mfg. no manufacturing data available
References (1) 1492
113
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PROFILE REPORT ON ARSENITES
Calcium Arsenite (88), Lead Arsenite (236), Potassium Arsenite (341)
Sodium Arsenite (377), Zinc Arsenite (454), and Copper Acetoarsenite (490)
1. GENERAL
The arsenite compounds are characterized as having the AsOp or AsO~
radical in contrast to the As04 radical of the arsenates. Only two of them
are believed to have significant commercial consumption in the United States.
Sodium arsenite is used as a poison in baits, a corrosion inhibitor, and a
weed killer, while copper acetoarsenite, commonly known as Paris Green,
finds general use as an insecticide. The other four arsenite compounds are
not being used in significant amounts by any commercial or industrial inte-
rests. ' Furthermore, it is difficult to even determine where to
purchase these chemicals, a fact that is detailed later. For these reasons,
the emphasis of this Profile Report will be directed towards the two com-
pounds that have commercial significance in industry or agriculture and
which could possibly occur as wastes from their use, or as surplus material.
The Profile Report will also present the available pertinent information on
the remaining compounds.
Cojjper Acetoarsenite
Paris Green is the common name for copper acetoarsenite [(CH,CO?)2Cu '
3Cu(As02)3]. In the late 19th century, it was a very common insecticide.
It is useful against the potato beetle9 the codling moth, and canker worms.
It has some inherent disadvantages however, which include the tendency to
burn foliage, rapid settling from suspensions and poor adhesive qualities.
It has been virtually replaced by lead arsenate and organic pesticides, and
is seldom used as an insecticide on crop plants. It is, however, finding
1742
considerable use as a larvicide to control mosquitoes. Paris Green is
115
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also employed for the control of dry wood termites by injection, in solid
form, into holes drilled in infested timbers. Production is at least
100,000 Ib per year.1785
It is widely believed that Paris Green and its homologs are complex
compounds of copper metaarsenite and the copper salt of acetic acid. The
ratio of the two constituents is normally very close to 3:1. Paris Green
is manufactured commercially by reacting sodium arsenite (prepared from
white arsenic and caustic soda) with copper carbonate and acetic acid.
Production is by means of a batch process. The reaction continues until
the insoluble, green product precipitates from the solution. A complete
reaction is indicated by a water white supernatant which contains only
•I 7QC
soda. This supernatant solution, said to be arsenic free, is dumped.
After application on crops, Paris Green breaks down rather rapidly.
Decomposition through hydrolysis results in the formation of soluble
arsenic compounds. This undesirable tendency to hydrolyze into soluble
arsenic compounds, in addition to the commercial product containing addi-
tional soluble arsenic compounds,prevents the use of Paris Green on plants
which are not highly resistant to the elements.
Sodium Arsenite
The common name sodium arsenite is given to a group of several com-
pounds that are used as insecticides in baits and as herbicides for highway
and railroad right-of-way weed control. These compounds probably consist
mainly of either sodium orthoarsenite (Na.,As03), sodium metaarsenite
(NaAs02),or a combination of the two. This compound is always sold com-
mercially in liquid form. It is manufactured by dissolving arsenic
trioxide in liquid caustic soda. The sodium arsenite solution is filtered
before drumming and the filter cake resulting from the filtration is buried
in public dumps. The composition of the waste filter cake was not
available and the public dump accepting these materials was not identified.
A typical, commercial sodium arsenite solution contains 4 to 6 Ib
of sodium arsenite per gal. of solution. Other uses for sodium arsenite
116
-------
solutions include treatment of certain plant diseases especially on grapes,
subterranean termites, and a cattle, goat and sheep dip.
As well as can be determined, only two companies remain as major
manufacturers of sodium arsenite. They are Chevron Chemical Corporation,
and Los Angeles Chemical Company. Chevron Chemical Corporation markets a
42 percent sodium arsenite product under the name of W-41 Corrosion
Inhibitor and Sodite Grape Spray, as well as a 55 percent arsenite product
called Arsenical Weed Killer. Production of the sodium arsenite solutions
from Chevron Chemical Company and Los Angeles Chemical Company are believed
to be 200,000 to 400,000 gal. per year on a 4 to 6 Ib per gal. basis.
Sodium arsenite is shipped in steel drums, the maximum size being 55 gal.
It is classified by Department of Transportation (DOT) as a Class B poison.
Other Arsenite Compounds
Very little information is available to define the properties,
production methods, uses and the consumption of the other arsenite com-
pounds that require discussion in this Profile Report. Lead arsenite and
zinc arsenite are not listed in the three major important reference works
on commercially available chemicals. ' ' Calcium and potassium
arsenite were mentioned only in one of the three sources. This would
indicate that these four arsenite compounds have a very small consumption
within the United States. A brief discussion on these four compounds is
presented in the following paragraphs.
Calcium arsenite (CaHAs03) is also known as monocalcium arsenite and
is a white powder of varying composition which has high toxicity.
It is classified as a Class B poison by the DOT, and can be used as an
insecticide and germicide. No other uses were found outside agriculture.
There are two lead arsenite compounds which are included in the scope
of this Profile Report. The first is lead mataarsenite which has the
formula Pb(As02)2< It is insoluble in water and its only listed use is
117
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an insecticide.1742 It is classified as a Class B poison by DOT and it
emits toxic fumes on heating. The other lead arsenite compound is
that of lead orthoarsenite, Pb(As03)2 • XH20. Generally, it has similar
physical and toxic properties as the metaarsenite compound and its only
known use is also as an insecticide.
There are two potassium arsenite compounds having properties suitable
for commercial use. The first is potassium metaarsenite (KAs02). It is
soluble in water and is considered very poisonous, the LD5Q for rats,
orally, being 14 mg/kg. 2 It is considered as a Class B poison by DOT.
No reference describing potassium arsenite being useful as a pesticide
was found. It was used in the manufacture of mirrors by reducing silver
salts to metallic silver, and was, at one time, used in solution for
1492
medicinal purposes. The other potassium arsenite compound is potassium
orthoarsenite, K3As03. It also is very soluble in water arid is classified
as a Class B poison by DOT. It is doubtful if any arsenicals are being
1433
used in medicine today. It was also determined that experts in mirror
plating technology had no knowledge of potassium arsenite currently being
used in the plating of mirrors. They indicated that the process would
probably be legally banned if not already obsolete. Thus, there is no
evidence of potassium arsenite being used in commercial enterprise.
Zinc arsenite, [Zn(As02)2] 1S a^so known as zinc metaarsenite (ZMA).
It is characterized by its low solubility in water and a toxicity that is
1742
similar to calcium arsenate. It is classified as a Class B poison by
the DOT and has been used as an insecticide and a wood preservative.
Market Trends for Arsenites
The arsenical pesticide market has been in broad decline in recent
years as a result of the strict government controls placed on them. These
materials are highly poisonous in all forms and prolonged application of
these and other arsenicals has caused a serious problem of arsenic buildup
in the soil. There also is the threat of arsenic being leached out of the
soil into streams and rivers where serious damage can occur to the aquatic
life.
118
-------
It is believed that the use of arsenicals will remain at approxi-
mately the same levels or may further decrease. Production of the materials
will, of course, decrease as demand falls. Thus a large excess of unusable
arsenite compounds is not expected to occur.
Sources and Types of Haste
The three major sources of arsenite wastes are: (1) pesticide manu-
facturers; (2) pesticide residue left in empty containers, and (3) surplus
pesticides stored in Department of Defense (DOD) facilities, and possibly
state/municipal facilities.
As indicated previously, the sodium arsenite solution is usually
filtered before drumming in its production process, and the resulting
filter cake is buried in public dumps. The composition of the waste
filter cake is not known, but probably contains both sodium arsenite and
arsenic trioxide, along with filter aid and water. No arsenic-containing
waste is found in the manufacture of copper acetoarsenite.
Both sodium arsenite and copper acetoarsenite are normally formulated
as water soluble concentrates or as aqueous solutions. As such, there are
usually 0.5 oz to 1 Ib of liquid residue left in the empty containers,
depending on the shapes and sizes of the containers. The safe and econo-
mical disposal of pesticide contaminated containers remains a serious
problem that is still unresolved.
Surplus arsenite pesticides currently in storage awaiting disposal
in DOD facilities include: 110 gal. of sodium arsenite in Florida, 30 gal.
of sodium arsenite in New York, 65 gal. of sodium arsenite in Illinois,
1,620 gal. of sodium arsenite in Alaska, 30,000 Ib of 5 percent copper
acetoarsenite solution in Florida. No arsenite pesticides stored in
state/municipal facilities have been identified.
-------
2. TOXICOLOGY
Human Toxicity
The arsenite compounds are highly toxic materials and are very
dangerous even in low concentrations.0766 The American Conference of
Governmental Hygienists has recommended a Threshold Limit Value (TLV) of 0.5
mi Hi grams/meter3 for all arsenic compounds. This value represents
the conditions to which nearly all workers may be repeatedly exposed
without adverse effect-
Acute arsenic poisoning from ingestion results in irritation of the
stomach and intestines with accompanying nausea, vomiting and diarrhea.
In severe cases, collapse and shock can occur with a weak, rapid pulse,
cold sweats„ coma or death. The diagnosis of latent chronic arsenic
poisoning is difficult since the condition may manifest itself with many
different and unpredictable symptoms. Included are disturbances of the
digestive tracts liver damage resulting in jaundice, blood and kidney
disturbances and a variety of skin abnormal ties.
Toxicity Towards Plant and Animal Life
Sodium arsenite is a strong herbicide while Paris Green harms all
but a very few types of plants. Thus they are generally considered toxic
towards plant life. No plant toxicity information was available on the
other four arsenite compounds but they should be considered as equally
toxic towards plants. The extreme toxicity of these compounds towards
human life can be considered the same for animal life as well. Extreme
precautions must be taken to prevent leaching from areas of application
into streams and rivers where the arsenic compounds can adversely affect
aquatic plant and animal life.
Emphasis has so far been placed on the arsenic constituent of the
arsenite compounds being discussed, but it should not be forgotten that
some of the cations involved in these compounds also have toxic properties.
120
-------
The cations of copper and lead are, under general conditions, also very
hazardous toward animal life. Therefore, the toxicity of these cations
should at least be considered in the scope of this Profile Report inasmuch
as they can render the appropriate arsenites even more toxic. The TLV's
3 0225
of these cations exclusive of arsenic are 1 mg/m and less.
3. OTHER HAZARDS
The arsenites do not exhibite any explosive, flammable, or volatile
properties nor do they present any other hazards.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage and Transportation
The arsenite pesticides require special consideration on their
storage, handling, transportation and disposal. Storage areas for these
compounds should be isolated from locations where food and animal feed
are stored. The solid arsenite compounds should be stored in the containers
originally packed by the manufacturer. The use of protective clothing,
goggles, gloves and dust filtering respirators are recommended for unload-
ing or otherwise handling these pesticides. Similar precautions are rec-
ommended for handling any liquid solutions. Spills of the solid materials
should be cleaned up using a vacuum cleaner after a fine spray of water
has been laid down to prevent dust. The liquid compounds or formulations
should be handled in an area such that in case of spills they can be con-
tained for easy cleanup or transfer to a sump where they will not create
a hazard if they are absorbed by the ground.
The arsenite compounds are labeled as Class B poisons and all DOT
regulations should be followed when shipping, storing or otherwise handling
them.
121
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Pisposaiy Reuse
The wholesale disposal of arsenite compounds into the air, water, or
soil must be considered completely unacceptable considering their high
toxicities. The U. S. Public Health Service has established a maximum of
0.05 mg/1 arsenic content (50 ppb) for drinking water if no other drinking
water is available. The ideal maximum is 0.01 mg/1 (10 ppb). The
acceptable criteria for the release of arsenite compounds into the environ-
ment are defined in terms of the following recommended provisional limits:
Contaminant in
Ajr
Calcium arsenite
Sodium arsenite
Provisional Limit
0.005 mg/MJ as As
0.005 mg/M as As
3
Copper acetoarsenite 0.005 mg/M as As
0.005 mg/M3 as As
Lead arsenite
Potassium arsenite
Zinc arsenite
Contaminant in
Water and Soil
0.005 mg/MJ as As
0.005 mg/M3 as As
Provisional Limit
Basis for Recommendation
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV •
Basis for Recommendation
Calcium arsenite
Sodium arsenite
0.05 ppm (mg/1) as As Drinking Water Standard
0.05 ppm (mg/1) as As Drinking Water Standard
Copper acetoarsenite 0.05 ppm (mg/1) as As Drinking Water Standard
Lead arsenite 0.05 ppm (mg/1) as As Drinking Water Standard
Potassium arsenite 0.05 ppm (mg/1) as As Drinking Water Standard
Zinc arsenite 0.05 ppm (mg/1) as As Drinking Water Standard
There are channels by which unused and unopened containers of the
arsenites can be returned to the manufacturer for resale. Representatives
of the manufacturers also indicated that they would accept contaminated or
otherwise unwanted material for reprocessing provided that the reprocessing
was possible and that a market existed. Foreign markets for arsenite
insecticides exist where the benefits of use outweighs the possible detri-
mental effects. The export of arsenicals should be licensed only when it
can be shown that the materials can be used to create an overall environ-
mentally desirable result. Arsenical pesticides are currently being
exported in relatively small amounts (at least 300,000 Ib in 1970).1738
122
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5. EVALUATION OF WASTE MANAGEMENT PRACTICES
There are six waste management methods which have applicability to the
arsenite compounds and which are currently being used or which might be
applied at a National Disposal Site. These methods apply mainly to the
arsenite compounds used as insecticides. The herbicides and soil steri-
lizers are not expected to create a disposal problem in that if they ever
require disposal they can be applied under new highway pavement and similar
construction which requires sterile soil. It should also be stressed that
regardless of the type of waste process employed, it still would be neces-
sary to deal with toxic arsenic in some form. The following is a discus-
sion of the options for the management of arsenite insecticides.
insecticides.
Option No. 1 - Recycle/Reuse
Representatives of the three remaining manufacturers of arsenic pes-
ticides have stipulated the conditions under which these materials were
returned to them for reprocessing or resale in the past. Each firm
accepted these arsenite materials for resale without any reprocessing if
the batch had originally been made by the firm and if the materials were in
their original unopened containers. Each firm above expressed its
reluctance to accept the product of other firms. Given the hypotehtical
situation of a batch of materials which was unusable but was refinable,
each firm indicated its willingness to accept it for reprocessing provided
that there was an available market for the material.1555' 1711> 1712
Option No. 2 - Long Term Storage
The use of large, weatherproof and siftproof storage bins or silos is
currently being used for the storage of other arsenic compounds, especially
1547
arsenic trioxide. Unwanted arsenites, already packed in the manu-
facturer's containers, could also be stored in these large weatherproof
bins. This approach is a relatively expensive one which requires land and
storage equipment in need for long, unknown periods of time before these
materials can be moved by sale or disposal to other outlets. Insofar as
123
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the arsenic compounds are poisonous in any form, long term storage is a
safe method for managing the arsenite wastes.
Option No. 3 - Land Spreading
Some userss when faced with unwanted stocks of some arsenite materials,
use land spreading as a means of disposal. This approach involves spread-
ing the waste materials over large amounts of land in very light applica-
tions so as not to significantly affect any of the crops or plant life
growing in the vicinity. This technique might be used for rare or
infrequent disposal of small amounts of waste but in light of the fact that
these compounds will build up in the soil by repeated application, this
method cannot be considered as completely adequate and other methods should
be considered first.
Option No. 4 - Export
Export of arsenite compounds, discussed previously, is not a disposal
process but is a means of arsenical management preventing large unwanted
overstocks provided that the advantages of their foreign use outweigh any
detrimental effects. It should not be considered for the sole purpose of
solving a U.S. problem at the expense of a foreign country.
Option No. 5 - Process for Recovery of Metals in Arsenites
American Smelting and Refining (ASARCO) has a process operating at
its Tacoma, Washington plant whereby they are recovering lead, copper,
zinc and possibly other metals from smelter dust which contain large
amounts of arsenic trioxide. The details of the process are proprietary
to ASARCO but it is conceivable that this basic process might be employed
to recover lead, zinc and copper from the arsenical insecticides and
herbicides as well. But it should be remembered that this process would
still result in the production of arsenic trioxide which is a disposal
1547
problem in its own right.
124
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Option No. 6 - Landfill
The disposal of arsenite compounds in sanitary landfills is generally
not acceptable because of the potential danger of ground and surface water
pollution, as well as possible occupational hazards resulting from on-site
handling. There are, however, certain approved sites located over nonwater-
bearing sediments or with only unusable ground water underlying them and
are completely protected from flooding and surface runoff or drainage such
as those designated as Class 1 sites in California. The disposal of small
stocks of arsenite pesticides or empty containers used to ship arsenite
pesticides in "Class 1" sites is considered as adequate, provided special
handling techniques as discussed in the previous section are employed to
protect site personnel.
To summarize, the adequate management methods for arsenite wastes
are: (1) recycle/reuse; (2) long-term storage; (3) ship to ASARCO for
recovery of the metal values and long-term storage of arsenic trioxide;
and (4) landfill in Class 1 sites.
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Arsenites are considered as candidate waste stream constituents for
National Disposal Sites for the following reasons: (1) the high degree
of toxicity of the compounds; (2) the nondegradable nature of the toxic
arsenic component of the compounds; (3) arsenite wastes are present in
sizable quantities as contaminated empty containers, surplus pesticides,
and from pesticide manufacture; (4) arsenite wastes are widely distributed
and are often handled by personnel without adequate training such as
farmers; and (5) facilities for treating other arsenic-containing materials
such as arsenic trioxide, arsenate, and organic arsenical wastes will be
required at National Disposal Sites.
The processes recommended for the treatment of arsenite wastes at
National Disposal Sites are:
.125
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Process Order of Preference Remarks
Long-Term First Choice Best current method as there is no
Storage market demand for As^CL
Landfill Second Choice Disposal sites must meet the
criteria for a California Class 1
site; recommended for the disposal
of contaminated empty containers.
-------
7. REFERENCES
0225. American Conference of Governmental Hygienists Threshold Limits for
1971. Adopted at 33rd Meeting, Toronto, Canada, May 1971.
Occupational Hazards, p. 35-40, Aug. 1971.
0766. Sax, N. I., Dangerous properties of industrial materials. 3rd ed.
New York, Reinhold Publishing Corp., 1968. 1,296 p.
1433. Kirk-Othmer encyclopedia of chemical technology. 2nd ed. New York,
Interscience Publishers, 1963.
1492. The Merck index of chemicals and drugs. 7th ed. Rahway, New Jersey,
Merck Co., Inc., 1960. 1,634 p.
1547. Personal communication. R. Loughridge, American Smelting and
Refining Company to J. F. Clausen, TRW Systems, Apr. 18, 1972
1555. Personal communication. H. Fisher, Chevron Chemical Company to
J. F. Clausen, TRW Systems, Mar. 79 1972
1570. Weast, R. C., ed. Handbook of chemistry and physics. 48th ed.
Cleveland, The Chemical Rubber Company, 1969. 2,100 p.
1711. Personal communication. W. Wade, Niagra Chemical Company to
J. F. Clausen, TRW Systems, May 11, 1972.
1712. Personal communication. H. Stevens, Los Angeles Chemical Company
to J. F. Clausen, TRW Systems, May 12, 1972.
1716. Personal communication. C. Ercegovich9 Pennsylvania State College,
Pesticide Research Center to J. F. Clausen, TRW Systems, May 11, 1972,
1728. Los Angeles Chemical Company. Data sheets and container labels for
arsenic pesticides.
1740 Personal communication. D. B. Barlow, Chevron Chemical Company to
J. F. Clausen, TRW Systems, May 12, 1972.
1742. Frear, D. E. H. Chemistry of insecticides, fungicides, and herbicides.
2d ed. New York, Van Nostrand Publishing Co., 1948. 417 p.
1763. Personal communication. G. Thompson, Rocky Mountain Research to
J. F. Clausen, TRW Systems, May 24, 1972.
1769. Personal communication. C. Sivertz, London Labs to J. F. Clausen,
TRW Systems, May 25, 1972.
1785. Personal communication. R. Holmes, Los Angeles Chemical Company to
J. F. Clausen, TRW Systems, May 25, 1972.
1790. Chem. sources, 1970 ed. Flemington, New Jersey, Directories Publishing
Co., 1969.
127
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HAZARDOUS fclASTES PROPERTIES
WORKSHEET
H. M. Name Calcium arsenite(88)
IUC Name
Common Names Mono calcium arsem'te' '
Structural Formula
CaHAsO
(2)
Molecular Wt. 164.00
(1)
Melting Pt.
Density (Condensed)_
-Density (gas)
Boiling Pt..
@
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp._
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper_
Upper_
Solubility
Cold Water_
Others:
Hot Water
Ethanol
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Poison class B
Comments UQPH a<^ 11
composition. High mammaliaiL
Coast Guard Classification Poison class B
5.no othop liotod usog^' Wh1te P°wder Pf
References (1) 1570
(2) 0766
(3) 1492
128
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Lead arsenite (236)
Structural Formula
IUC Name Lead meta arsenite
Common Names
Pb(AsO,)
2'2
0)
Molecular Wt. 421.03^ Melting Pt. Boiling Pt.
Density (Condensed) 5.85 g/cc @ Density (gas) • _ @
Vapor Pressure (recommended 55 C and 20 C)
9 0
Flash Point Auto1gn1tion Temp._
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility
Cold Water insol. Hot Water Ethanol_
Others: sol. acids
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Poison Class B Coast Guard Classification Poison Class B
^mi t^ toxir fump<; r>n hpafi'nn' ' InEflCticidO Only lictcd UCC
References (1) 1570
(2) 0766
(3) UP2
129
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Lead arsenite (236)
IUC Name Lead ortho arsenite
Common Names
Structural Formula
Pb3(As03)2 •
Molecular Wt. 954.45 +XH20 Melting Pt.
Density (Condensed) 5.85^' @ Density (gas)_
Vapor Pressure (recommended 55 C and 20 C)
Boiling Pt._
0
Flash Point
Auto1gnit1on Temp._
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower
Upper_
Upper_
Solubility
Cold Water
Hot Water
Ethanol
Others: S Alk and MHO,
Acid, Base Properties_
Highly Reactive with_
Compatible with
Shipped in
ICC Classification Poison class B
Coast Guard Classification Poison class B
Comments Fmit.<; tnxir . fumpg nn
insect.iriHp it: nnly
use
' '
References (1) 1570
(2) 0766
(3) J492
130
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Potassium arsenite (341)
IDC Name Potassium meta arsenite
Common'Names
Structural Formula
KAsO
(1)
Molecular Wt. 146.02
(1)
Melting Pt.
Density (Condensed) @
Vapor Pressure (recommended 55 C and 20 C)
9
Flash Point
Density (gas)_
Boiling Pt..
9
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. X) Lower_
Solubility
Upper_
Upper_
Cold Water sol.
Others:
(1)
Hot Water sol.
(1)
Ethanol slightly sol
Acid, Base Properties_
Highly Reactive with_
Compatible with
Shipped in
ICC Classification Poison Class B
Coast Guard Classification
Comments Very po1S-pn.ous.-
silver salt to metallic silver
14 mg/Kp. Miprnn manufartiirp -
1) Merck says item nf rnmrnprrp i«: appvnv
727:
'] 2) Hade into Karsenite solution, Fowlers solution for medicine for chronic dermatides,
charea^ ' _^
References (1). 1570
(2) 1492
131
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Potassium arsenlte (341)
IUC Name Potassium ortho arsenita
Structural Formula
Common Names
K3As03
(1)
Molecular Wt. 240.23
(1)
Melting Pt.
Boiling Pt..
Density (Condensed)
Density (gas)_
Vapor Pressure (recommended 55 C and 20 C)
&
Flash Point
Autolgnition Temp._
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Upper_
Upper_
Solubility
Cold Water very sol.
Others:
(1)
Hot Water
Ethanol sol.
(1)
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Poison class B
Coast Guard Classification
Comments Verv poisonous. LD^Q for rate? orally is.14.mo/Kg. Mirror manufacture - reduce
silver salt to metallic silverA2). 1) Merck says item of commerr.e is apprnv,
2) Made into K arsenite solution (Fowlers solution) for medicine for chronic dermatitus,
,(2) '
choreav
References (1) 1570
132
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Sodium arsenite
IUC Name Sodium meta arsenite
Common Names
Structural Formula
129.91
(1)
Molecular Wt.
Density (Condensed) 1-87 g/cc @
Vapor Pressure (recommended 55 C and 20 C)
Melting Pt.
Boiling Pt.
Density (gas)_
Flash Point
Autoigm'tion Temp._
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower_
Solubility
Cold Water_
Others:
very sol.
(1)
Hot Water very sol.
Upper_
Upper_
(1)
^lightly
Acid, Base Properties_
Highly Reactive with_
Compatible with_
Shipped in steel drums. 55 gallon
ICC Classification poison class
Coast Guard Classification poison r
Comments: used in manf. of arsenical soaps, termites, and herbicides for RR and highway
weed control
(3)
References (1) 1570
(2) 0766
(3). .1432
133
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Zinc arsenite (454)
structural formula
IUC Name Zinc in-Arsenlte
Common Names 7«//i^n > 0
) !
i
Molecular Wt. 279.2^ Melting Pt. Boiling Pt. ;
Density (Condensed) @ Density (gas) @ . !
Vapor Pressure (recommended 55 C and 20 C)
@ @
9 " I
Flash Point Autoignition Temp. <
Flammability Limits in Air (wt %) Lower Upper ;
Fynln^ivp 1 imitQ in Aiv fwt *£\ 1 nwps^ llnnpp
; Solubility
:
•
Cold Water Low solubility^' Hot Water Ethanol i
Others:
Acid, Base Properties
Highly Reactive with '.
;
Compatible with
!
• Shipped in
• ICC Clflssifi ration Poison B Coast Guard Classificati
on Poison B
> Comments Highly toxic, a wood preservative, insecticide. Toxicity similar to calHnm I
arsenate(2J
"i
\
: References (1) 0766 \
1 (2) 1742
C
I
134
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Copper Acetoarsenite (490)
!
IUC Name
Structural^ Formula
Common Names
(CH3COO)2 Cu • 3 Cu(As02)3
Molecular Wt. 669
Melting Pt.
Density (Condensed)
Density (gas)
Boiling Pt._
&
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower
Explosive Limits in A1r (wt. %) Lower
Upper_
Upper_
Solubility
Cold Water slightly iniuhlp^3) Hot Water_
Others: soluble in dil. acids
Acid, Base Properties
Ethanol
Highly Reactive with_
Compatible with_
Shipped in fiber drums, metal pails and cans
ICC Classification poison class B
Comments -.
Oral
In rats
Coast Guard Classification poison class B
T2f
-------
PROFILE REPORT
Magnesium Arsenite (245)
1. GENERAL
The Profile Reports on Calcium Arsenite (88), Sodium Arsenite (377),
Copper Acetoarsenite (490), Lead Arsenite (236), Potassium A**senite (341),
Zinc Arsenite (454), and Arsenic Trioxide (51) indicate that for waste
arsenite compounds and arsenic trioxide, long term storage is the best
option for waste management. Disposal of arsenite compounds or arsenic
trioxide in typical landfills is not recommended because of their high
toxicity and appreciable (though slight) solubility. Though the quantity
of arsenite projected for manufacture over the next five years is small,
considerable arsenic trioxide will be collected as a byproduct of copper,
lead,,and gold smelting industries and as a residue from destruction by
combustion of organic compounds containing arsenic.
Even though the arsenite compounds and As^Oo are stored in sealed
containers, their solubility creates a potential problem. Ferric and
magnesium arsenites are very slightly soluble. Therefore, the arsenites
and AspO., can be rendered nearly insoluble by addition to a suspension of
magnesium hydroxide, and thus their long term storage made safer.
The physical/chemical properties of magnesium arsenite are not given
because magnesium arsenite is not a compound but a name applied to a group
of compounds.
2. TOXICOLOGY
All arsenic compounds are highly toxic materials and are very dangerous
even in low concentrations. However, the solubilities of mixtures of
arsenites and magnesium hydroxide are so low that these mixtures are
relatively non-toxic, magnesium hydroxide being given to treat arsenite or
137
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As2CL poisoning. The American Conference of Governmental Hygienists
recommended a Threshold Limit Value (TLV) of 0.5 mg per cubic meter for
nope
all arsenic compounds. A detailed discussion on arsenite toxicology
is given in the Profile Report on the Arsenite Compounds (88, etc.).
3. OTHER HAZARDS
Magnesium arsenite does not exhibit any explosive, flammable, or
volatile properties nor does it present any other hazards in an alkaline
environment. When reacted with strong acids, the arsenic content of the
material is solubilized.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
As previously indicated, magnesium arsenite is formed in the treatment
of other arsenic wastes. It has no known use. Magnesium arsenite
with magnesium hydroxide should be handled in the same manner as described
in the Profile Report on the Arsenites (88, etc.).
The arsenite compounds are classified by the Department of Transportation
(DOT) as Class B Poisons.
Because the wholesale disposal of arsenite compounds into the air,
water or soil is considered completely unacceptable, aqueous discharge of
arsenic compounds has been limited to concentrations below 1 ppm. Storage
of arsenic compounds including As^Oo and the arsenites is usually in large,
waterproof and siftproof storage bins or silos. This approach is expensive,
but usually satisfactory. If the storage period is anticipated to be very
long or the stored material is subject to exposure through natural causes,
As203 or arsenite compounds should be added to a suspension of magnesium
hydroxide. This mixture should be stored under the controlled conditions
noted above.
138
-------
The safe disposal of magnesium arsenite is defined in terms of the
recommended provisional limits in the atmosphere, in potable water and
in marine habitats. These recommended provisional limits are as follows:
Basis for
Contaminant in Air Provisional Limits Recommendation -
Magnesium Arsenite 0.005 (as As) rog/M3 0.01 TLV
Contaminant in Water Basis for
and Soil Provisional Limit Recommendation
Magnesium Arsenite 0.05 (as As) mg/1 Drinking Water
Standard
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
As previously indicated, magnesium arsenite is made as a product of
a waste treatment process. It should be stored in weatherproof and sift-
proof storage bins or silos without additional treatment except the water
present may be permitted to evaporate. This is a recommended mode of
disposal.
The disposal of arsenite compounds in sanitary landfills is generally
not acceptable because of the potential danger of ground and surface water
pollution, as well as possible occupational hazards resulting from on-site
handling. There are, however, certain approved sites located over nonwater-
bearing sediments or with only unusable ground water underlying them and
are completely protected from flooding and surface runoff or drainage such
as those designated as Class 1 sites in California. The disposal of small
stocks of magnesium arsenite wastes in "Class 1" sites is considered as
adequate, provided special handling techniques as discussed in the previous
section are employed to protect site personnel.
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Magnesium arsen.ite is considered as a candidate waste stream constituent
for National Disposal Sites for the following reasons: (1) the high degree
of toxicity of the compound; (2) the nondegradable nature of the toxic
139
-------
arsenic component of the compound; and (3) facilities for treating arsenites
and other arsenic-containing materials such as arsenic trioxide, arsenate,
and organic arsenical wastes will be required at National Disposal Sites.
The processes recommended for the treatment of magnesium arsenite
wastes at National Disposal Sites are:
Process Order of Preference Remarks
Long-Term First Choice Best current method as there
Storage is no market demand for As^Oo
Landfill Second Choice Disposal sites must meet the
criteria for a California
Class 1 site; recommended for
the disposal of magnesium
arsenite contaminated solid
wastes.
140
-------
7. REFERENCES
0225. American Conference of Governmental Hygienists. Threshold Limits
for 1971. Occupational Hazards. Aug. 1971. p. 35-40.
0634. Sullivan, R. J. Air pollution aspects of arsenic and its compounds,
Bethesda, Litton Systems Inc., Sept. 1969. 72 p.
0766. Sax, N. I. Dangerous properties of industrial materials. 2d ed.
New York, Reinhold Publishing Corporation, 1957. 1,467 p.
141
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PROFILE REPORT
Ammonium Chromate (21), Ammonium Dichromate (22),
Potassium Chromate (343), Potassium Dichromate (345),
Sodium Bichromate (379,388), Sodium Chromate (386)
1. GENERAL
The hexavalent chromium (Cr ) salts of the alkali metals and ammonia
find widespread use in industry and are found as wastes in virtually every
industrial area in the United States. However, since the trivalent form
of chromium (Cr ) is also poisonous and hazardous to the environment, it
will also be discussed as part of this Profile Report insofar as it plays an
important role when it occurs in the handling and disposal of waste hexa-
valent chromium compounds. For the purposes of this report, the term "chro-
mates" will be used to describe all the hexa-i alent chrome oxides in either
the chromate or dichromate form.
Manufacture
Sodium chromate and dichromate are produced by roasting the chrome
ore in the presence of soda ash, lime or a mixture of the two. The
resultant sodium chromate from the roasting process is further processed
to yield the dichromate.
2 Na2Cr04 + H2S04 + Na2Cr207 + Na2S04 + H20
The byproduct sodium sulfate is recovered and sold as chrome salt cake for
use in the paper industry with about 0.2 percent Na2Cr2Oy. A simplified
flow diagram of this process can be found in the Encyclopedia of Chemical
Technology and additional details on the manufacture are found in NDC
Pollution Control Review No. 6.0653
143
-------
Potassium chromates and dichromates can be produced by ore roasting
using potassium carbonate much in the same manner as with sodium chromates,
but a process using potassium chloride and sodium chromate is economically
preferable.
Na2Cr04 + 2KC1 + K2Cr04 + 2NaCl and
Na2Cr20? + 2KC1 •* K2Cr20? + 2NaCl
Ammonium chromate and di chromate are also produced by combining the
appropriate sodium salt with ammonium sulfate in a process similar to that
for the potassium compounds.
Na2Cr04(NH4)2S04 + (NH4)2Cr04 +• Na2$04 and
Na2Cr207(NH4)2S04 +
The distribution of Na9Cr907 consumed by various industries in 1968 is as
1 R06
follows from Chemical Profiles.
Pigments 40 percent
Leather tanning. 18 percent
Chromic acid( plating) 17 percent
Metal treatment 10 percent
Textiles and dyes 6 percent
Export and other 9 percent
The estimated 1972 demand for Na0Cr007 made in 1968 was 145,000
1506
tons. The physical, chemical and hazardous properties of these
materials are discussed later in this report and are included on the
attached worksheets.
Sources and Types of Chromate Wastes
All of the industries mentioned above, with the possible exception of
the pigment industry, can be considered significant sources of these
144
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hexavalent chrome (Cr ) wastes. A situation which serves to illustrate
the wide spread use of these materials is that virtually all cooling towers
in use as heat sinks in industry and large air conditioned buildings contain
chromates which serve as algaecides and corrosion inhibitors. The amount
of blowdown, i.e.,.cooling water removed to prevent mineral buildup in the
cooling water from evaporation losses, is in the multiple billions of gal-.
i C tC
Ions containing 10 to 300 ppm Cr . The more specific details on Cr
wastes from industry sources are outlined below.
In addition, surplus chromates and dichromates are sometimes stored
in Department of Defense (DOD) facilities awaiting proper disposal. These
include: (1) anhydrous sodium chromate—33,837 Ib in California, 100 Ib
in Washington; (2) sodium dichromate dihydrate--7qt in Virginia, 500 Ib in
Georgia; (3) potassium dichromate--3,000 Ib in Tennessee.
Metal Finishing Industry
The electro plating and metal finishing industry stands out as a major
source of chromium and chromate waste products. A representative of Industrial
Filter and Pump Inc. of Chicago, Illinois estimates that in the decorative
chrome plating operation only 10 percent to 20 percent of the chrome consumed
in the industry winds up on the plated product. 71»147
The wasted chrome compounds occur as a result of rinsing operations,
spillage, mists from hot tanks and large amounts of chromates used in
cleaning, pickling and post plating solutions which become easily spent
and are frequently discarded. The actual chromium plating tanks are in
themselves not major sources of chromate wastes. The lifetime of a
chromium plating tank can be considered indefinite because of the many
available procedures for removing unwanted impurities.
The OPD Chemical Profiles on sodium bichromate and chromic acid indi-
cates that about 40,000 tons of chromium compounds, calculated as chromic
acid, will be consumed by the metal finishing industry in 1972. Assum-
ing that the higher estimates of 20 percent of the chromium purchases will
145
-------
be ultimately found on a product, then about 329000 tons of chromium, cal-
culated as chromic acid, will ultimately end up as various chromate wastes.
Lancy has recently estimated that no more than 25 of the largest decorative
chrome plating shops in the United States have any type of chrome solution
recycling systems. James Zebers, of Industrial Pump and Filter Corp.
estimates that recycling accounts for approximately 30 percent of the total
T A "7 1 '
chromium waste. This would indicate that at least 22,000 tons are sub-
ject to single pass, once only use before ending up as wastes.
These chromate compounds are finding their way to waste status for
three main reasons. The cleaning-treating baths have too many impurities
of the type that makes recovery infeasible for any plant. Small plants
that account for about half the total plating work are too small to econom-
ically justify recycling equipment. Many plants are permitted to discharge
into municipal sewers after reduction of Cr to Cr due to political and
technological reasons which are varied and result from local conditions.
+3
Chromate wastes are at least reduced to the trivalent state Cr in
the great majority of the shops in the United States. Those few that dis-
charge Cr will be restrained from doing so by municipal authorities in
the near future. Once in the trivalent form, the Cr is either (1) pre-
cipitated as the hydroxide by pH adjustment in the plant and picked up by
a disposal firm, or (2) the neutralized Cr solution is directly discharged
to the sewer.
The composition of the chromium wastes from the metal finishing industry
varies widely with the type of metals being processed, the metals being
plated, the design of the equipment, and other important factors. The
levels of chromium normally vary from a few ppm to a few percent of the
total waste stream. Wastes from metal finishing may include many other
metals such as copper, zinc, cadmium, and nickel. Likely to be included in
the stream are grease, oils, acids, organic additives and cleaning agents.
The forms and composition of some typical chromium containing metal finishing
waste streams have been obtained from various industry sources and are
summarized here (Table 1).
146
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TABLE 1
TYPICAL METAL FINISHING WASTE STREAMS CONTAINING CHROMIUM
Waste Description
3000 ppm of a mixture of chromium, 20% aluminum sulfate
and 35% sulfuric acid (trace of copper, nickel, lead)
12.5% chromic acid - dichromate in 10% to 30% sulfuric
Form
Liquid
Liquid
Source:
Industry/Process
Aluminum anodizing
bath with drag out
Metal finishing
acid with 5000 to 120,000 ppm chromium (85% as Cr+3)
with 100-1000 ppm lead, copper and iron
Dilute chromic acid solution containing chromium +3 at Liquid
100-200 ppm and chromium +6 at 2000 to 4000 ppm with
traces of organics (combined wash waters).
Partially neutralized aqueous plating waste containing Liquid
5-10% zinc chromate, and 5-10% zinc phosphate contaminated
with various organic oils.
Solutions of chromates and dichromates in sulfuric acid Liquid
(6-12%) containing 5000-170,000 ppm chromium with copper,
lead and traces of organics.
0.1-0.5% chromium, 100-400 ppm copper, 100-600 rK,,, nickel Liquid
in 5-10% aqueous hydrofluoric-hydrochloric acid.
1 to 20% chromium in solids concentrations of 10-80% from Sludge
settling and/or dewatering processes. Includes copper in
varying amounts with varying amounts of inert filter aids.
100-1000 ppm chromium as alkaline cyanide solutions (6-20%) Liquid
with copper in varying amounts with possible traces of
organics, nickel, lead and zinc.
5-6% chromic acid in water solution with 1% iron Liquid
9% chromic acid in 13% aqueous sulfuric acid Liquid
0.1-1% sodium or potassium dichromate in water, usually Liquid
sulfuric acid present in a 1-15% concentration
Metal plating
Zinc plating
Formation of protective and
decorative coatings (metals)
Plating preparation (metd'i)
Chemical process (plating
operations, manufactu^'TO.
metallurgical)
Metal plating (formation of
protective and decorative
coatings)
(1) Metal Plating
(2) Shipbuilding
Metal finishing and plating
(1) Metal Finishing
(2) Shipbuilding
(3) Plating
-------
Textile Mill Products
The sources of chromate materials in the textile industries arise from
two rather distinct sources. One is the wide spread use of cooling towers
in the textile industry which have the normal operating wastes from blow-
down of 40 to 400 ppm chromate solutions. The chromate containing blowdown
waters are normally fed into the common waste flow for-subsequent treatment
within the plant.
The second source of chromate compounds are those used to oxidize
and make, wash fast, the sulfur dyes for relatively inexpensive cotton
goods. The oxidizing agents are normally the chromate compounds in water/
acetic acid. Excess amounts of the chromate oxidizing solution are carried
over into rinses from the dying vats along with spent trivalent chromium
materials. The waste water from the dye oxidization and rinsing operations
are fed into the common waste effluent stream within the mill for subse-
quent treatment. I', is not possible to determine the amount of chromate
compounds which are normally consumed in these dye oxidizing steps. How-
ever, since Chemical Profiles indicates that 6 percent of the dichromate
prodution was utilized by the textile industry one might estimate that
about 8,700 tons were consumed in all textile operations including dye
oxidization and maintenance of the cooling towers. The larger portion of
these chromium compounds occur as wastes. The current trends for using
chrome in sulfur dying reflect decreasing use. Sulfur dyes are becoming
obsolete and chromate oxidizing agents are being replaced by perborates and
peroxides as a result of environmental considerations.
Most of the southern mills have some sort of on-site water treatment
facilities whereby the Cr+ and the Cr+3 wastes are treated by normal
reduction/precipitation techniques. An official of the American Associa-
tion of Textile Chemists and Colorists indicates that virtually all of the
southern mills have responded to the needs for water treatment. They have
either entered into joint operation with a neighboring city or they have
constructed their own on-site water treatment facilities. The northern
-------
textile mills benefiting from the greater availability of water can be
characterized as normally sewering their chromium wastes after reducing
the chromates to Cr+3.1480
A. D. Little has presented tabulated data for chromium waste effluent
as a result of sulfur dying in their rough draft report of textile mill
products under the industrial waste studies program for the water quality
ncpo
office of EPA. This data can be used to calculate chromate wastes if
the amounts of sulfur dyed textiles are known.
Pigments
Pigment colors are made from the chromate compounds by various precip-
itations with barium, lead, molybdenum and zinc. They are employed widely
in the paint, printing ink and plastics industries. They account for about
40 percent of the dichromates consumed in the United States. The pro-
cess can be batch, wherein the precipitation, washing, and filtering steps
are carried out within one or two vats. The operation may also be continuous,
employing separate operations in a series of cascades. Most of these pigment
compounds are highly insoluble and therefore are not a source of soluble
hexavalent chrome. However, zinc chromate is slightly soluble in water and
for that reason requires greater attention to reduce the losses during pur-
ification. All of the five largest plants have their operations east of the
Mississippi river in Cleveland, New York, Delaware, Chicago and New Jersey.
The companies contacted in the study all indicated that they are under strict
regulations regarding the discharge of chromium wastes and all have their own
on-site treatment facilities for Cr+ reduction and hydroxide precipitation.
They indicated that the pigment manufacturing processes were operated so as
to minimize both chrome compound wastes and the wastes of the heavy metals
for economic reasons. It was stated that, whenever possible, rinse waters
are recycled to the precipitation tanks in order to reduce the wasting of
the heavy metal ions or the hexavalent chrome compounds which often are
added in excess to promote precipitation. Some production figures from 1970
were supplied by E. I. DuPont as being estimated of production in the entire
industry: chrome yellow, (PbCrO^) 31,752 tons; molybdate orange, 10,858
tons; zinc yellow, 7,291 tons.
149
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Chromate wastes are generated, however, from the manufacture of solvent-
based paints as a result of kettle washings and equipment clean-up. The
typical solvent-based paint sludge is characterized by the following com-
position: 4.5 percent inorganic pigment (excluding titanium dioxide),
8.5 percent titanium dioxide, 14.5 percent pigment extenders, 25.0 percent
binders, and 47.5 percent organic solvents. It is estimated that 137,000
Ib of chromium, mostly as lead and zinc chromates, are lost through 36,800,000
Ib of solvent-based paint sludges each year. The paint sludges are currently
•>X
being disposed of in sanitary landfills, although incinerator systems to
handle these wastes are now under development.
A lesser hazard associated with the chromate-based paints is the paint
residue left in containers discarded in municipal dumps. An estimated
963,000 Ib of chromium (mostly in the form of chromates) are lost through
the 221,000,000 Ib of paint residue each year.
The Tanning Industry
The leather tanning and finishing industry is a significant consumer
of chromate and dichromate chemicals for use in chrome tanning operations.
Sodium dichromate is the only chemical which is normally purchased for
chrome tanning. It is reduced to chromium sulfate before hide impregnation
and fixing. Some tanning plants purchase the sodium dichromate and convert
it within the plant to chromic sulfate. Others purchase the chromic sul-
fate in powder form from tanning supply houses. Chromic sulfate is the
principal chromium waste from the tanning operations and this is discussed
in greater detail in the Profile Report on Chromic Sulfate (486).
Photography
Chromate compounds occur in the photographic industry as a result of
the gravure and leather press plate making operations. The industry pur-
chases only the ammonium chromates and appear to be the only consumer of
these low volume chromate salts. Chromate solutions at about 4 to 5 percent
are used to sensitize and polymerize gelatin coatings over copper plates
150
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when exposed to light coming through a photo negative. Unexposed chromate
coated gelatins are then washed away in water streams thereby exposing
portions of the plate for etching. Chromates occur as wastes from wash-
ing the plates as well as from the chromate tanks which require dumping at
4 to 6 month intervals. An average size tank or tray contains 5 to 10 gal.
of the solution. These tanks are normally emptied down a sink without any.
processing. An estimated 500 such plants are performing this type of
operation across the nation. The resultant 4,000 Ib of dichromates
being dumped from this industry do not represent a significant hazard or
pollution problem. As part of the manufacture of the lithographic plates
discussed above, they are frequently chrome-plated to increase their
resistance to wear on the presses. But this is normally done in a com-
mercial plating shop with no different processes than normal chrome plating.
2. TOXICOLOGY
The chromates are very corrosive when in contact with sk"in and mucuous
membranes. They produce ulcerous lesions which heal slowly. Salts of
chromic acid have been associated with lung cancer. The Threshold Limit
Value (TLV) for the hexavalent chromates Cr+6 is 0.1 mg/m3 air while that for
225
the reduced chromous and chromic ions is 0.5 mg/m3 air.
The chromium containing sludges when occuring as a result of the
standard reduction/hydroxide precipitation treatment methods can present a
twofold toxicological hazard if landfilled. The sludges can contain sol-
uble chromium salts and complexes which if leached out of the fill can be
detrimental. It is also possible for acid species to be landfilled with
the hydroxide sludges, dissolve them, forming water soluble chromium
compounds. These water soluble materials can find their way to a potable
water table from an inadequately placed landfill site.
151
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3. OTHER HAZARDS
The chromatesj save those of ammonium ion do not present a critical
flammability or explosive hazard. Since they are powerful oxidizers9 they
should not be mixed with reducing agents or organic materials. Chromates
are not corrosive to metals in the solid state. Concentrated aqueous
solutions of the chromates at high temperatures will attack metals of which
the least resistant are copper and its alloys (brass). Additional infor-
mation is presented on the attached worksheets.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage, and Transportation
This material must be stored so that it will not be subject to high
temperatures,, nor contact reducing agents. The type of container must be
resistant to the particular chromate compound being stored. The creation
of dust must be avoided during storages transfer and handling of the
materials. Workers among these materials should be adequately protected
from contact of the materials with skin, eyes9 or internal organs. Since
large ingested doses can cause permanent injuries or deathB adequate super-
visory control of all operations and education of employees is highly
important.
Guidelines considered adequate for the safe handling and storage of
chromate wastes can be found in the data sheets of the Manufacturing Chemists
Association, ' but since chromium is toxic in all forms except in
metallic form, the disposal of these materials in a safe manner must be
carefully controlled. The Department of Transportation (DOT) classifies
ammonium chromate and dichromate as flammable solids and requires a yellow
warning label but Sax mentions no such requirements for the sodium and
potassium salts. All additional federal regulations governing the
handling, storing, loading and shipping of these materials must be observed.
152
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Disposal/Reuse
Due to the fact that hexavalent chromium is extremely toxic towards
marine plant and animal life, its discharge into open waterways is severly
restricted. The Federal Water Quality Act of 1965 limits the discharge of
this material. Each state is allowed to set its own upper limit for hexa-
valent chromium, but it is felt that the state levels are all set near the
0.05 ppm level recommended by the U. S. Public Health Service (USPHS) for
potable water. The upper limit for discharge of hexavalent chromium to
municipal sewage systems is normally set near 5 ppm, because this material
can cause severe problems with biological treatment processes in sewage
treatment plants unless discharged in low concentrations and dilutes on it's
way to the treatment plant. For the safe disposal of chromates, the accept-
able criteria for their release into the environment are defined in terms of
the following recommended provisional limits:
Contaminant in Air
Ammonium Chromate
Ammonium Dichromate
Potassium Chromate
Potassium Dichromate
Sodium Chromate
Sodium Dichromate
Contaminant in
Water and Soil
Ammonium Chromate
Ammonium Dichromate
Potassium Chromate
Potassium Dichromate
Sodium Chromate
Sodium Dichromate
Provisional Limit
0.001 mg/M3 as Cr03
0.001 mg/M3 as Cr03
0.001 mg/M3 as Cr03
0.001 mg/M3 as Cr03
0.001 mg/M3 as Cr03
0.001 mg/M3 as Cr03
Provisional Limit
0.05 ppm (mg/1) as Cr
t
0.05 ppm (mg/1) as Cr
0.05 ppm (mg/1) as Cr
0.05 ppm (mg/1) as Cr
0.05 ppm (mg/1) as Cr
0.05 ppm (mg/1) as Cr
153
Basis for
Recommendation
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
0.01 TLV
Basis for
Recommendation
Drinking Water
Standard
Drinking Water
Standard
Drinking Water
Standard
Drinking Water
Standard
Drinking Water
Standard
Drinking Water
Standard
-------
Reclamation of chromium values from sludges resulting from the treat-
ment of chromate wastes is often technically feasible, but seldom practiced
because of economical considerations.
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
There are a number of available methods for use in handling hexavalent
chromium (Cr ) wastes in aqueous solutions. Only two on-site treatment
methods are used to any large extent in industry. These are reduction-
precipitation and ion exchange. The remaining methods are not widely used,
in development stages or are otherwise unproven. Finally there remains
+3
the practice of sewering large amounts of chrome wastes in both Cr and
c/6.
Option No. 1 - Reduction/Precipitation
. ^
By far the most widespread method used for removing Cr ° from industrial
waters is chemical reduction followed by precipitation. The pH of the
aqueous wastes is adjusted to between 2 and 3 and the hexavalent chromium is
reduced to the trivalent state by the addition of suitable reducing agents.
These reducing agents may vary depending on the availability of low cost
by-product reducing agents from neighboring industries or reducing agents
which may occur as wastes from nearby processes. Such reducing agents may
include bottled SOp or that from flue gas, sodium sulfite and bisulfite
from flue gas scrubbing liquids, iron filings, brass arid aluminum chips or
machining wastes. Plants without a reducing agent occuring as a waste or
by-product normally employ sulfur dioxide gas, sodium metabisulfite, or
ferrous sulfate. After reduction of the chromium to the trivalent state,
the solution is made alkaline to pH 9.5 and the metal hydroxide is precip-
A
itated along with the hydroxides of other heavy metals. Aluminum sulfate
(alum) or other suitable flocculating agents are often added to aid in pre-
cipitation, settling and clarification of the effluent. This procedure can
be carried out either in batch type processes or continuous processes and
complete equipment systems are available for performing this process on an
automated or semi-automated operation. The biggest drawback of this pro-
cedure is the removal and disposal of the highly hydrated metal hydroxide
154
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sludges. It is not unusual for these sludges to contain upwards of 75 to
80 percent water by volume. Precipitation and settling is normally a slow
procedure and with high effluent flow it is normally necessary to have set-
tling ponds or lagoons in which to allow the slow coagulation process to
occur, the clear effluent removed and the sludge dried. No feasible eco-
nomic process has yet been developed for the reclamation of any valuable
metals or other credits from this type of sludge since it often contains
various other organic and inorganic material which hinders purification
and recovery. In the tanning industry where the chromium wastes are already
trlvalent it is possible to wash the chromium hydroxide/sludges, add sulfur
acid to regenerate the chromic sulfate, and return it to the tan liquor
tanks. However, at present this procedure is not considered economically
feasible and is practiced very little if at all.
Chromic Hydroxide Sludge Disposal. There are three methods for handling
the hydroxide sludges resulting from reduction/precipitation of hexavalent
chrome which normally have other matter present. Listed in what is believed
to be order of decreasing usage, they are landfill, ocean disposal and in-
cineration. Landfill ing involves burying the sludge which normally has been
"aged" by storage in ponds where it yields up most of the water entrained
in the sludge. Landfills have the advantage of isolating materials in areas
where they will remain buried and are not likely to cause problems by con-
taminating underground water supplies or otherwise damaging neighboring
plant and animal life. The disadvantages of landfill arise as a result of
improper site selection, inadequate waste preparation, or mixing with acid
+3
wastes which could result in dissolution of Cr into the leachate. This
dissolution could lead to absorption of Cr into the desert floor. The
v
subsequ€rnt use of the landfill area for recreational or other purposes may
be restricted by the materials which have been landfilled.
Ocean disposal of the sludge is accomplished by barging it to a recog-
nized dumping area. Sea disposal has the advantage of not requiring site
management other than testing the surrounding sea for waterborne pollu-
tants. Disadvantages include possible conversion of sludges to soluble
products harmful to sea life and the possible migration of hazardous con-
centrations to outside of the dumping area.
155
-------
Incineration removes the water and organic material from the sludge but
the ash normally is not economically recovered and is currently land-filled.
The Cr03 produced from incineration is water soluble while other oxide
forms, CrO, Cr^CL and CrCL are insoluble and present no problem. It is
not known what form of the oxide is likely to occur from normal sludge
incineration.
The costs for the chemicals used in the reduction of the hexavalent
chromium to the' trivalent chromium range from about 6 cents to 22 cents
per Ib of Cr reduced depending on the reducing agents used. They
can also be much less if waste product reducing agents are used. The
amount of material necessary to readjust the pH of the solution to about
9.5 varies with the ratio of the acidity to the chromium content. There-
fore, no actual figure for pH adjustment can be calculated. Lancy has
attempted to predict the cost of metal finishing waste treatment and his
work can be used as a guideline to predict costs once a particular waste
st. earn -,s characterized.
Option No. 2 - Ion Exchange
Ion exchange processes for chromate removal from aqueous solutions
have been used since the advent of chromate resistant resins 10 to 15
years ago. The obvious advantages here are that, due to the concentrative
effects, it is possible to apply this process in recycling chromate mater-
ials or in concentrating wastes for transport to centralized disposal or
conversion. Recent technology has enabled ion exchange to be extended into
the fields of large volumes of water containing small concentrations of
Cr thus making it applicable to chromates from cooling tower blowdown.
Exhausted anion resins are normally regenerated by diluting them with
a sodium hydroxide/sodium chloride solution to displace the chromates and
then following with a pure sodium chloride solution to completely regen-
erate the resin. The cost of chemicals for regenerating the resin t?ds
are estimated to be between 4 and 5 cents per pound of chromate as compared
-------
with 17 to 19 cents for purchasing a pound of chromate. The capital costs
for an ion exchange system to handle a 100 gpm flow rate with 40 ppm Cr+6
is estimated to be about $40,000 to $50,000. This figure of course will
vary widely with type of plant, location and type of accompanying materials
in the chromate solution.
The manner in which an ion exchange bed operates provides the basis
for potential difficulties and disadvantages should the system be put to
use. The chromate solution must be free of foreign materials such as
organics, greases or solids for efficient operation. These would tend to
physically clog the system or deactivate the catalyst bed. This problem
can normally be overcome by a filtering process before such wastes enter
the exchange beds. The other more serious disadvantage to ion exchange
operation is that of the critical dependence on flow. These beds are
designed to operate with a particular efficiency at a certain set flow.
Should this flow be exceeded for even short periods of time, the efficiency
for absorbing the chromate anion decreases drastically resulting in an
effluent from the exchange bed which has chromate residues exceeding the
designed effluent limits.
Option No. 3 - Discharge to Municipal Sewers
The practice of sewering Cr and often Cr is still considered to
be widespread. » There are several reasons for this type of prac-
tice. From discharge permit information, the local sanitary officials
normally have a good idea of the discharge levels and locations of discharge
points for particular materials in their sewer systems. They can coordinate
with industry at the various discharge points and establish levels of
cooperation for the discharge of excessive pollutants. Often the case is
such that all sources along a sewer line for a particular type of toxic
material, chromium in this case, can discharge at apparent excessive but
controlled levels by cooperation with sanitary officials and the result
will be non-injurious to any waste water treatment facility. There are a
number of reasons for this type of practice. Initially, the sanitation
157
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officials do not have, or do not enforce, regulatory guidelines as to the
0
amount of chromium that a particular source may discharge. Secondly, the
presence of chromium and other heavy metal ions in sewage water has a
significant beneficial effect on the sewage system. The heavy metal ions
are instrumental in precipitating sulfides thereby helping to abate the
odor problem as well as reduce the corrosive reactions between the sul fides
and the underground concrete lines.
The chrome wastes are normally all reduced to Cr and precipitated in
transit to the sewage treatment plant. It is thus removed in the primary
treatment steps and subjected to sludge digestion which does not change its
form. The chrome precipitates, combined with the sludges, are then dis-
posed of by the standard techniques such as incineration, landfill or ocean
disposal. The long term accumulative effects of these sludges is unknown
at the present time. In spite of the benefits that may arise from chromium
in the sewer lines, it is felt that the sanitary officials would just as
soon have no chrome in their systems due to the inherent problems that
arise with chromium's toxicity related to its ultimate disposal.
Option No. 4 - Direct Precipitation
The direct precipitation of dichromate or chromate ions by the use
of barium or lead salts is a workable method but is not normally economi-
cally feasible unless a market as pigments for the precipitates is avail-
able. The lead and barium compounds used in this precipitation are also
highly poisonous, water soluble and relatively expensive. Furthermore,
large excesses of the heavy metal cation would be necessary to effect a
removal below a safe limit of 1 ppm since barium chromate, for example,
has a solubility of about 4 ppm at 25 C. '
Option No. 5 - Ion Flotation
Ion flotation is a process by which a surfactant is added to the
effluent which reacts with the chromate ion to be removed and forms an
insoluble surface active compound. Being surface active, this new material
158
-------
will tend to concentrate at the interface between the solution and air as
in a foam where there are high liquid/air interfaces. It is then possible
to skim the foam from the solution thereby removing the chromate and di-
chromate anions in a higher concentration in the foam than in the solution.
Sheppard and Jones refer to such a system which employed a three stage
series operation. A feed stream containing 100 ppm dichromate was separated
into effluent and foam stream containing 8 ppm and 468 ppm dichromate re-
spectively. The concentration of surfactant in the solution was 400 ppm.
Experiments conducted by Battelle Memorial Institute indicate that favorable
+fi +^
removal efficiencies for Cr and Cr are being accomplished on a bench
scale. The use of this type of system in waste treatment plants at
present is not evident.
Option No. 6 - Electrochemical Conversion
Electrochemical reduction can be used in which hexavalent chromium can
be electrolytically reduced to the trivalent state on a bed of semi conductive
materials through which low voltage current flows. The development of such
a process has advanced to the state where it is possible to treat dilute
solutions of chromate ion rather effectively and the manufacturers of such
equipment have stressed the applicability of such a device for cooling tower
blowdown waters. Since the product is trivalent chromium, this procedure
might possibly replace the chemical reduction previously discussed. This
process does not concentrate chromates in effluents but may have process
merit in dealing with concentrates received for ultimate conversion and
recovery of chromium at a National Disposal Site.
Option No. 7 - Electrodialysis
Elect^odialysis, also in its developmental stages, offers some advan-
tages over ion exchange for the removal of chromates. The membranes used
in this process do not require regeneration and the products from such a
treatment process are chromate free water for recycling plus a concentrated
solution of the original chromate salt which can also be recycled with or
without further purification. The capabilities of the membranes are the
159
-------
limiting factor at this time and the development of new membranes as well
as a more sophisticated electrodialysis cell design may yield an equipment
that is effective at chromate concentrations below 100 ppm, present ef-
fective limitation.
Option No. 8 - Adsorption on Activated Carbon
Activated carbon has been shown to remove hexavalent chromium from
a synthetic waste solution in lab studies. Carbons produced from coal
seem to have the best removal efficiencies. Battelle has conducted
a pilot plant study and demonstrated that the technical feasibility of
the process more or less parallels that of ion exchange in that the
activated carbon must be disposed of or regenerated.
Option No. 9 - Liquid-Liquid Extraction
The removal of Cr in aqueous media can be accomplished by a series
of liquid-liquid extractions using an organic phase containing an extractant.
Preliminary studies indicate that this process is functional over a wide
range of chromate concentrations. The extractants are easily regenerated
and the process appears to be adaptable to various volumes of waste flow.
Option No. 10 - Reduction of Cr With Activated Carbon
Only sketchy details are available from an observation made during
other activated carbon experiments by Battelle. Incomplete reduction
occurs below pH3 with no reduction above pH3.
Option No. 11 - Reverse Osmosis
Plating shop installation of "R.O." units exist but not necessarily
for Cr compounds. Battelle studies indicate only fair removal efficien-
cies for Cr but new technology is developing rapidly.0773 The membranes
are susceptable to extremes in pH and hence their use for acidic forms of
the chromates are questionable.
-------
To summarize, the adequate management methods for chromate wastes
are: (1) reduction/precipitation followed by disposal of the waste chromic
hydroxide sludges in either approved landfills or by incineration; (2) ion-
exchange; and (3) electrochemical reduction. Direct precipitation of the
chromates by the use of barium or lead salts involves potential handling
difficulties because of the poisonous heavy metals involved. The other
processes discussed—ion flotation, electrodialysis', activated-carbon
adsorption, liquid-liquid extraction, activated-carbon reduction, and
reverse-osmosis—are all in various stages of development and show promise
as near future methods for treating dilute chromate wastes.
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
The chromates and dichromates discussed in this Profile Report are
considered as candidate waste stream constituents for National Disposal
Sites for the following reasons: (1) the high degree of toxicity of the
compounds; (2) hexavalent chromium oxides cannot normally be reduced to
the nontoxic elemental chromium form; (3) the chromate and dichromate
wastes appear in sizable quantities; (4) a substantial portion of the
chromate and dichromate wastes are contributed by small plating shops
that cannot afford waste treatment equipment; and (5) the disposal of
waste chromium hydroxide sludges can be more adequately handled at a
centralized facility and the chromium and heavy metal values present can
be more readily recovered if such a need arises.
For the disposal of concentrated hexavalent chromate wastes at National
Disposal Sites, it is recommended that a reductive-precipitative facility be
constructed. This scheme is by far the most applicable approach for treating
chromate concentrates in a National Disposal Site. The sub-process of electro-
reduction might have merit to replace the chemical reduction step of the
operation and save on necessary reducing chemicals. The technique is ef-
ficient and adequate for large scale removal of chromates. The effluent can
+3
have 1 to 2 ppm levels of Cr or lower.
161
-------
The permanent containerized storage or proper landfill ing of chromium
waste sludges or their incinerated residues are recommended for ultimate
disposition. The landfill sites used must be located over nonwater-bearing
sediments or have only unusable ground water underlying them and must also
be completely protected from flooding, surface runoff or drainage, so that
all waste materials and internal drainage are restricted to the site. The
economics of transportation to the landfill or storage site must be considered
in the decision to transport the hydrated sludge or to incinerate it prior
to shipment. Such studies will be necessary in site selection and process
recommendation for sites in various parts of the nation. The very same
facility is usable for many of the toxic metal compounds which would also
be likely to need disposal from time to time including cadmium, mercury,
lead, copper, and arsenic.
162
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7. REFERENCES
0087. Federal Water Pollution Control Administration. Cost of clean water.
v. 3. Industrial Waste Profiles, No. 7, Leather Tanning and
Finishing. Publication No. I.W.P.-7. Washington, 1968. 60 p.
0215. Manufacturing Chemists Association. Properties and essential infor-
mation for safe handling and use of chromic acid chromium trioxide.
Chemical Safety Data Sheet SD-44. Washington, 1952.
0217. Manufacturing Chemists Association. Properties and essential infor-
mation for safe handling and use of sodium and potassium dichromates
and chromates. Chemical Safety Data Sheet SD-46. Washington, 1952.
0225. American Conference of Government Industrial Hygienists. Threshold
limits for 1971. Occupational Hazards. Aug. 1971, p. 35-40.
0317. Fulmer, M. Rid sewage of toxic inorganics. Water and Waste
Engineering, 8(1):26-27. Jan. 1971.
o
0522. Arthur D. Little, Inc. Textile mill products. Waste Quality Office,
Environmental Protection Office, May 28, 1971.
0617. Shepherd, C. M., and R. L. Jones. Hexavalent chromium; toxicological
effects and means of removal from aqueous solution. AD-717348.
Report No. NRL-7215. Washington, Naval Research Laboratory,
Jan. 4, 1971. 21 p.
0553. Jones. H. R. Environmental control in the inorganic chemical industry,
1972. Park Ridge, New Jersey, Noyes Data Corporation. 255 p.
0766. Sax, N. I. Dangerous properties of industrial materials. 3d ed.
New York, Reinhold Publishing Company, 1968. 1,251 p.
0773. Battelle Memorial Institute. An investigation of techniques for
removal of chromium from electroplating wastes. Environmental
Protection Agency Industrial Pollution Control Branch and Metal
Finishers Foundation, Mar. 1971. 95 p.
0783. Battelle Memorial Institute. A state-of-the-art review of metal
finishing waste treatment. PB-203 207. Ohio, Nov. 1968. 88 p.
1433. Kirk-Othmer encyclopedia of chemical technology. 2d ed. 22 v. and
suppl. New York, Wiley-Interscience Publishers, 1963-1971.
1471. Personal communication. J. Zebers, Industrial Pump and Filter Corp.,
to J. Clausen, TRW Systems, Mar. 21, 1972.
1472. Personal communication. A. Olsen, Parker Company, subsidiary of
Udylite Corp., to J. Clausen, TRW Systems, Mar. 21, 1972.
163
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REFERENCES (CONTINUED)
1473. Personal communication. G. Fitzgerald, Alco. Cad-Nickel Corp., to
J. Clausen, TRW Systems, Mar. 20, 1972.
1474. Personal communication. L. Lancy, Lancy Laboratories, to J. Clausen
TRW Systems, Mar. 14, 1972.
1480. Personal communication. T. Alspaugh, Cone Mills, to J. Clausen,
TRW Systems, Mar. 17, 1972.
1492. Merck and Company, Inc. The Merck index of chemicals and drugs.
Rahway, New Jersey, 1960. 1,643 p.
1500. Lancy. L. E. An economic study of metal finishing waste treatment.
53rd Convention of American Electroplaters Society, June 1966.
1504. Personal communication. Dr. Roddy, American Leather Chemists
Association, University of Cincinnati, to J. Clausen, TRW Systems,
Mar. 28, 1972.
1506. Chemical Profiles. Sodium bichromate and chromic acid. New York,
Schnell Publishing Company, Inc., 1970.
1510. Personal communication. Mr. Garber, Hyperion Sewage Treatment Plant,
to J. Clausen, TRW Systems, Apr. 4, 1972.
1511. Personal communication. J. Nagano, Hyperion Sewage Treatment Plant,
to J. Clausen, TRW Systems, Apr. 6, 1972.
1570. Chemical Rubber Company. Handbook of chemistry and physics. 47th ed.
Cleveland, 1966. 1,500 p.
164
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I HAZARDOUS WASTES PROPERTIES
1 WORKSHEET
H. M. Name Ammonium Chromate (21)
structural Formula i
IUC Name
Common Names (NH, KCrO,
424
I
Molecular Wt. 152.09(1) Melting Pt. d(1) Boiling Pt.
Density (Condensed) 1.91 & 12 c Density (gas) @
Vapor Pressure (recommended 55 C and 20 C)
@ @
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper
0 :
Explosive Limits in Air (wt. %) Lower Upper !
Solubility ,.,
Cold Water 40.5 g/ioo cc 30 c" ' Hot Water d(1) Ethanol insoi.(1)
Others: sltghtly soluble in NH..
Acid, Base Properties Aqueous solution is alkaline
!
Highly Reactive with Reducing agents . Shock or heat will explode
it.
Compatible with
Shipped in Metal and fiber drums, tank trucks and tank cars
100 Ibs |
ICC Classification Flammable solid, yellow lab Coast Guard Classification same1 :
Comment1; Loses some NH, in air, keep well closed
.
;
References (1) 1570
(2) 0766
(3) 1492
i
1
J
165
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Ammonium dichromate (22)
IUC Name
Common Names
Structural Formula
Molecular Wt. 252.10
(1)
Melting Pt.
(1)
Boiling Pt._
Density (Condensed) 2.15 g/cc @ 25 c _ Density (gas)
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Autoignition Temp._
Flammability Limits in Air (wt %) Lower
Explosive Limits in Air (wt. %) Lower
Solubility
Cold Water
Others :
Upper
Upper
at 15 c(l) 30 c(1)
30.8 g/100 cc Hot Water 89 g/ioo cc at Ethanol soi.
Acid, Base Properties
1% aqueous soln. has pH 3.95
Highly Reactive with reducing agents,
Compatible with_
Shipped in
100 Ibs
ICC Classification |iam. solid, yellow label, Coast Guard Classification
_
Commen tS very toxic . strong oxidlzerr decomposition becomes ap.1 f-sustalirlng at 7?S r.
with heat and N. evolution __ ______________ -
References (1) 1570
(2) 0766
(3) 1492
166
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name
IUC Name
Potassium Chromate (343)
Structural Formula
Common Names
tarapacaite
Molecular Wt. 194.20
(1)
Melting Pt. 968.3
Density (Condensed) 2.732 @ _ 20 c(1) Density (gas)
Vapor Pressure (recommended 55 C and 20 C)
(1)
Boiling Pt.
@
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower
Explosive Limits in Air .(wt. %) Lower
Upper
Upper_
a)
(
Cold Water 62.9 g/lOQ cc 20 c( Hot Water 79.2 g/ioo cc
Others: __
Acid, Base Properties Alkaline to phenolphthalein
100 c
(1)
Ethanol inso1
Highly Reactive with reducing agents, organics
Compatible with_
Shipped in metal and fiber drums, multiwall paper bags, tank cars and tank trucks
ICC Classification
Coast Guard Classification
Comments Irritants, ulcers, lune cancer
*• J
Being replar-gH hy
References (1) 1570
(2) 0766
(3) 1492
167
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Potassium dichromate (345)
Structural Formula
IUC Name
(2)
Common Names Potassium bichromate K Cr 0
Red potassium chromate
Molecular Wt. 294.19(1) Melting Pt. 398 c(1) Boiling Pt. d 50°
Density (Condensed) 2.68 0 25 c^ Density (gas) &
Vapor Pressure (recommended 55 C and 20 C)
Flash Point Autoignition Temp._
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility at 0 c(l)
a,. ~ ^^J./ --- VJ.,
Cold Water 4.9 g/lQO cc Hot Water 102 g/lOQ cc at Tthanol insol
Others:
Acid, Base Properties 10% aq- soln- has 3-57 P'!
Highly Reactive with reducing agents
Compatible with_
Shipped in Metal and fiber drums, multiwall paperbags, tank cars and tank trucks
ICC Classification Coast Guard Classification
Comments
References (1) 1570
(2) 0766
168
-------
r
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Sodium dlchromate (379,388)
IUC Name
Common Names sodium acid chromate
(2)
Structural Formula
«2H 0
Molecular Wt. 298.1
(i)
100
Meltinq Pt. anh.
Boiling Pt. d 400
(2)
Density (Condensed) 2-52 @ 13 c Density (gas)
Vapor Pressure (recommended J5 C and 20 C)
G> @
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower
Upper_
Upper_
Solubility
Cold Hater 238 8/10° cc at ° c Hot Water 508 Z/1QO cc at 80 cEthanol
Others:
Acic, Base Properties_
Highly Reactive with reducing agents
Compatible with Metals, wood fiber products
Shipped in Metal drums, fiber drums, multiwall papersacks, tank cars and tank trucks
IATA Class A, no label
ICC Classification £ftMfccCiatrix£aaMaf«fttJa«x no limit (pass and
Comments MCA requires warning label
References (1) 1570
(2) 0766
JL69
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name .Sodium chromate (386)
Structural Formula
IUC Name
Common Names
Molecular 'kit. 162 Melting Pt. Boiling Pt._
Density (Condensed) 2.710 @ Density (gas) @ .
Vapor Pressure (recommended 55 C and 20 C)
Flash Point Autoignition Temp.
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility ,,*.
Cold Mater 87-3 g/10° cc at 30 c Hot Water; Ethanol slightly soluble
Others:.
Acid, Base Properties
Highly Reactive with reducing agents
Compatible with Metals and wood fiber products
Shipped in Metal drums, paper bags (multiwall), tank cars and tank trucks
ICC Classification Coast Guard Classification
(2)
Commpnf:* highly toxic, strong oxidizer
References (1) 1570
(2) 0766
170
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PROFILE REPORT
Chromic Acid (114)
1. GENERAL
Introduction
Chromic acid is the common name given to chromium VI trioxide, CKL.
It is also known as chromic anhydride. It is a poisonous, powerfully
oxidizing, red, solid material. It is used almost exclusively in the
metal finishing industry where approximately half is used in direct
decorative chrome plating and the remainder is used in an assortment of
metal treating baths including etching, passivation, and conversion
1981
coating. The annual consumption for chromic acid is estimated to be
approximately 30,000 tons with 90 percent being used in the metal treating
industry and the remaining 10 percent used for catalyst manufacture,
refractory, or exported.
Manufacture of Chromic Acid
Chromic acid is produced by the reaction of sodium dichromate and
sulfuric acid. Oleum, i.e. sulfuric acid charged with sulfur dioxide, is
1982 1983
also commonly used. ' The mixture is heated to about 400 F whereupon
the mixture separates into a chromic acid layer and an upper, less dense,
sodium bisulfate layer. The layer containing the product is drawn off and
solidified on water cooled flaking rolls while the bisulfate layer, which
contains small amounts of chromium compounds, is returned to the supplier .
for reuse in making sodium dichromate. ' Normally there is no
refining of any large amounts of this product which is characteristically
99.5 percent pure. The product is either sold as flake or is ground
before packing in steel drums. There is no significant liquid effluent
from the process except for occasional water washes from cleaning the
process equipment. These washings are directed to sumps or evaporation
ponds on the factory premises.
171
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Sources and Types of Waste Chromic Acid
The metal finishing and chrome plating industry is responsible for
very large amounts of chromic acid wastes. It is estimated that between
25,000 and 30,000 tons of chromic acid will be consumed in the metal
finishing industry in 1972. Losses occur from metal treating tanks
which are customarily dumped as they load up with grease, dirt, etc. The
other major source of wasted chromic acid arises from dragout. i.e. the
losses that occur from rinsing the parts after plating and metal treating.
Equipment is available to minimize losses from dragout and recover reusable
water, but the expense in purchasing this equipment cannot normally be
justified in terms of the value of recoverable chromic acid. The waste
management problems of chromic acid, as well as other hexavalent chrome
compounds, are detailed in the Profile Report which discusses the ammonium,
potassium, and sodium salts of the chromates and dichromates (21,345, etc.).
The composition of the chromium wastes from the metal finishing industry
varies widely with the type of metals being processed, the metals being plated,
the design of the eouipment, and other important factors. The levels of
chromium nominally vary from a few ppm to a few percent of the total waste
stream. Wastes from metal finishing may include many other metals such as
copper, zinc, cadmium, and nickel. Likely to be included in the stream are
grease, oils, acids, organic additives and cleaning agents. The forms and
composition of some typical chromium containing waste streams from metal
finishing are:
(1) 3000 ppm of a mixture of chromium, 20 percent aluminum sulfate
and 35 percent sulfuric acid (trace of copper, nickel, lead).
(2) 12.5 percent chromic acid - dichromate in 10 percent to 30 percent
sulfuric acid with 5000 to 120,000 ppm chromium (85 percent as
Cr+3) with 100 - 1000 ppm lead, copper and iron.
(3) Dilute chromic acid solution containing chromium +3 at 100 - 200
ppm and chromium +6 at 2000 to 4000 ppm with traces of organics
(combined wash waters).
(4) Solutions of chromates and dichromates in sulfuric acid (6-12
percent) containing 5000 - 170,000 ppm chromium with copper, lead
and traces of organics.
172
-------
(5) 0.1 - 0.5 percent chromium, 100 - 400 ppm copper, 100 - 600 ppm
nickel in 5 - 10 percent aqueous hydrofluoric-hydrochloric
acid.
(6) 5-6 percent chromic acid in water solution with 1 percent
iron.
(7) 9 percent chromic acid in 13 percent aqueous sulfuric acid.
In addition, surplus quantities of chromic acid are sometimes stored in
Department of Defense (DOD) facilities awaiting proper disposal. At present,
this includes 800 Ib in New Mexico and 200 Ib in California.
2. TOXICOLOGY
Chromium trioxide CrO~, when dry or in solution as chromic acid, is a
very corrosive material and a strong oxidizing agent. If it contacts skin
or mucous membranes, it can produce ulcerous lesions which heal slowly.
The salts of chromic acid have also been associated with lung cancer. The
Threshold Limit Value (TLV) for hexavalent chromates (Cr VI) is 0.1 mg/m
in ai'r. Drinking water should contain no more than 0.05 ppm. The
corrosive nature of chromic acid dictates that the material should also be
kept away from contacting terresterial plant surfaces. No exact information
was available regarding the harmful effects of chromic acid on aquatic
plant and animal life but it is reasonable to assume that chromic acid is
potentially very harmful.
3. OTHER HAZARDS
Chromic acid does not present a critical flammability or explosive
hazard by itself, but since it is a powerful oxidizing agent, it should not
be mixed with organic materials or other reducing agents. Even dilute
organic solutions containing chromic acid should not be heated for fear of
a violent reaction; Chromic acid is not corrosive to metals in the
anhydrous state but concentrated aqueous solutions will attack some metals,
the least resistant of which are copper and its alloys (brass).
173
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4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, storage, and Transportation
When occurring as a concentrated waste product either in solid or
solution form, chromic acid must be stored away from high temperatures or
reducing agents. The correct container must be used for the solid or
solutions. The creation of CrO^ dust must be avoided during storage,
transfer and handling of the material. Workers should be adequately
protected from contact of chromium trioxide with skins eyes, or internal
organs. Since small ingested amounts can cause permanent injuries or
death, adequate supervisory control of all operations and education of
employees on the hazards of chromium trioxide is recommended.
General information on the properties and safe handling guidelines
of chromium trioxide are found in the data sheet of the Manufacturing
Chemists Association. Any and all additional federal regulations
governing the handling, storing, loading, and shipping of these materials
are to be observed.
Disposal/Reuse
The Federal Water Quality Act of 1965 limits the discharge, to open
waterways, of chromium trioxide and all other hexavalent chrome compounds.
Each state is allowed to set its own upper limit for hexavalent chromium
discharge but it is felt that the limits will all be set near 0.05 ppm,
1752
the drinking water Standard recommended by the U. S. Public Health Service.
The upper limits of hexavalent chromium discharge to municipal sewage systems is
normally set by local authorities at about 0.05 ppm, a relatively low
concentration, since this material, when more concentrated, can cause
severe problems with biological water treatment processes in sewage treatment
plants. Practically speaking, this maximum discharge limit is very often
ignored when the discharge point is far enough from the water treatment plant
so that adequate dilution is usually achieved. Additionally it is felt that
174
-------
hexavalent chrome is almost always reduced to Cr III and precipitated as the
sulfide while in transit within the sewer by various other chemicals contained
in the sewage.
For the safe disposal of chromic acid, the acceptable criteria for its
release into the environment are defined in terms of the following recommended
provisional limits:
Contaminant and Basis for
Environment Provisional Limit Recommendation
Chromic acid in air 0.001 mg/M as Cr03 0.01 TLV
Chromic acid in water 0.05 ppm (mg/1) as Cr Drinking Water
and soil Standard
The metal finishing industry has been placed under pressure to control
the amount of chromium trioxide that is being wasted to sewers and landfills
but in many areas the water quality officials have not set levels of
1473
compliance or they are still allowing large discharges. Technology is
rapidly developing which will enable the. industry to economically recover
a significant part of chromic acid for reuses but the current general
concensus is that while the technology may exists the costs are still too
high for economical operation in the average size metal finishing facility.
The economics of chrome products may force the installation of chrome
recovery. The types of processes which already have applicability towards
chromic acid recovery include ion exchange and possibly reverse osmosis.
Systems under consideration for potential applicability include
electrodyalysis and liquid, extraction.
5. EVALUATION OF WASTE MANAGEMENT PRACTICES
Equipment and processes to handle waste chromic acid in solution can
be divided into two main groups. The first group covers the equipment and
methods to conserve chromium compounds by reconcentrating, purifying, and
reusing them, or returning the concentrates to the manufacturer for
reprocessing. The other group covers the method of treating hexavalent
175
-------
chrome for ultimate disposal such as sewering or landfill without any
attempt at recovery or reuse. The waste treatment processes and equipment
are identified (Table 1), and discussed in considerable detail in the
Profile Report on the ammonium, potassium, and sodium salts of chromate
and dichromate anions (21,345, etc.).
6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Chromic acid is considered as a candidate waste stream constituent for
National Disposal Sites for the following reasons: (1) the high degree of
toxicity of the material, (2) chromic acid cannot normally be reduced to the
nontoxic elemental chromium form; (3) chromic acid wastes appear in sizable
quantities; (4) a substantial portion of the chromic acid wastes are con-
tributed by small plating shops that cannot afford waste treatment equipments;
and (5) the disposal of waste chromium hydroxide sludges can be more adequately
handled at a centralized facility and the chromium and heavy metal values
present can be more readily recovered if such a need arises.
For the disposal of concentrated chromic acid wastes at National Disposal
Sites, it is recommended that a reductive-precipitative facility be constructed.
The reduction to Cr III is preferred over direct precipitation of Cr VI because
the required lead and barium reagents are highly poisonous, expensive and
require large excesses to precipitate below safe levels. Precipitation of
these materials, while not recovering chromium resources, is currently the
most reasonable approach for handling these substances based upon current
chrome prices (Table 1). The sub-process of electro-reduction could have
merit in replacing the usual chemical reduction step. This very same batch
process facility would be usable for many of the other heavy metal compounds
which also occasionally require disposal. These include cadmium, mercury,
lead, copper, and arsenic.
The permanent containment and storage or proper landfilling of the
resultant chromium waste sludges or their incinerator residues are recommended.
The economics for transportation to the landfill or storage site will have to
be considered in the decision to transport the hydrated sludge or to incinerate
176
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TABLE 1
METHODS OF CHROMIUM TRIOXIDE CONCENTRATION FOR WATER
PURIFICATION AND MATERIAL REUSE
Method
Remarks
Ion Exchange
Ion flotation
Electrodialysis
Adsorption on activated
carbon
Liquid-liquid extraction
Reverse osmosis
Used in last 10 to 15 years for industrial
chromate removal.
Not developed enough for industrial use.
Not yet efficient enough for industrial
use.
Efficient for final water polishing but
creates problem of used carbon disposal.
Shows high merit but is only in early
development stages
Installations exist but not for chromates.
Technology developing rapidly.
METHODS FOR UNRECOVERABLE FINAL DISPOSAL
Reduction to Cr III and
precipitation by pH
adjustment
Direct precipitation with
barium or lead
Electrochemical conversion
to Cr III
Use is widespread in industry.
are normally landfilled.
Precipitates
Efficient method if market available for
the precipitates as pigments. Not
frequently used.
Can be used to reduce to Cr III prior to
precipitation, thereby eliminating need
for reducing chemicals. Shows promise.
177
-------
it prior to shipment. In addition, incinerating or dewatering the sludges
should also be considered in an effort to make the entire disposal process
more efficient from the standpoint of metals recovery.
The other processes mentioned (ion exchange, ion flotation, dialysis,
reverse osmosis, liquid/liquid extraction, etc.) will result in reduced
amounts of chromic acid wastes when they are employed in the metal finishing
industry, but they are not applicable to National Disposal Sites since they
are designed to process dilute aqueous wastes which could not economically
be transported to a National Site. However one of these processes might
be incorporated to purify the water used within the Disposal Site itself.
.178
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7. REFERENCES
0215. Properties and essential information for safe handling and use
of chromic acid. Chemical Safety Data Sheet SD-44, Washington,
Manufacturing Chemists Assoc., 1952. 12 p.
0225. Threshold limit values for 1971. Jji Occupational Hazards,
Aug. 1971, p. 35-41.
0766. Sax, N. I., Dangerous properties of industrial materials, 3d ed.
New York, Reinhold Publishing Corp., 1968. 1,251 p.
1433. Kirk-Othmer encyclopedia of chemical technology, 2d ed. 22 v. and suppl
New York, Interscience Publishers, 1966. 899 p.
1473. Personal communication. G. Fitzgerald, Alco Cad Nickel Corp. to
J. Clausen, TRW Systems, Mar. 20, 1972. Chromium in metal
plating.
1506. Chromic acid. Jjn chemical profi1ess New York, Schnell Publishing
Co, 1969.
1752, Public health service drinking water standards. U. S. Department
of Health Education and Welfare, Public Health Service,
Publication No. 956, Environmental Control Administration,
Rockville, Md.s 1962. 61 p.
1981. Personal communication. D. Hutchinson, Harshaw Chemical Company
to J. Clausen, TRW Systems, May 30, 1972, Chromium III compounds
and chromic acid.
1982., Personal communication. M. Wagner, Essex Chemical Corporation to
J. Clausen, TRW Systems, May 30, 1972. Chromic acid; production
producers, consumers.
1983. Personal communication. R. Banner, Diamond Shamrock, Divisional
Technical Center to J. Clausen, TRW Systems, May 30, 1972.
Chromic acid; Production Producer, customers.
179
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. <• ..-'•A..!^M^i-' ...,v , .- ,U '.. . . . • -^-7-
'.
\
H. M. Name Chromic Acid (114)
IUC Name Chromium Tri oxide
Common Names Chromic Anhydride
Molecular Wt. 100.01
Density (Condensed) 2.70 @
Vapor Pressure (recommended 55 C
! e
i Flash Point noncombustible
Flammability Limits in Air (wt %)
'Explosive Limits in Air (wt. %)
Solubility
Cold Water 164.9g/100g at 0 C
HAZARDOUS WASTES PROPERTIES
WORKSHEET
Structural Formula
CrO
Melting Pt. 197C decomposes Boil ing Pt.
20 C Density (gas) • G>
and 20 C)
(3 (3
Autoignition Temp.
Lower N/A upper N/A
Lower N/A Upper N/A
Hot Water 206. 7g/100g at 100C Ethanol
\ Others: H?SOA
Acid, Base Properties concentrated solutions at elevated temperatures attack most common
metals and some plastics
Highly Reactive with readily oxidisable orqanics(may ignite); intimate contact with oowerful '
reducing agents can cause violent
(2)
explosionsv '
Compatible with certain oxidant-resistant plastics and mild steel
::
Shipped in steel barrels or drums, ICC spec. 6A, B or C or 17H, 37D, 37E
* '
ICC Classification oxidizing material Coast Guard Classification oxidizing material ",
Comments TLV(ACGIH) 0.1 mg/m3
in solution DOT classification
air
is corrosive liquid, whit.P lahoi, i gallon mav
* References (1) 0215 ;
"(2) 0766
180
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PROFILE REPORT ON
CADMIUM AND CADMIUM COMPOUNDS
Cadmium (81). Cadmium Powdered (82),
Cadmium Chloride (83), Cadmium Oxide (85),
Cadmium Phosphate (86), Cadmium Nitrate (479).
Cadmium Potassium Cyanide (480), Cadmium Sulfate (481)
1. GENERAL
Introduction
Cadmium is a metal which is not found as a free mineral in nature.
Since pure cadmium is never found in a natural state and cadmium minerals
are not found in concentrated form, metallic cadmium is always prepared
commercially as a by-product of primary metal industries, principally the
zinc industry. Cadmium is found not only in zinc ore but in lead ore,
copper ore and other ores that contain zinc minerals. It is intimately
associated with the zinc and when ores containing several minerals are
separated, the cadmium remains with the zinc. Since the separation process
is not exact, lead concentrate will contain a small quantity of zinc and a
proportionally small amount of cadmium.
Cadmium compounds contain the element mainly in the divalent state.
Cadmium ions in solution react with carbonates, phosphates, arsenates,
oxalates, and ferrocyanides to form white precipitates, usually highly
hydrated, whose physical characteristics vary with the conditions of
precipitation.
In 1968 about 96 percent of the cadmium produced in the United States
was primary cadmium and 4 percent was from secondary production - 45 percent
recovered from foreign ores; 36 percent from domestic ores; 15.percent from
imported flue dust; 4 percent secondary metal derived from reprocessing
scrapped alloys.
-------
Cadmium in zinc concentrates from domestic mines is estimated at
5S304,000 Ib/year. This is based on mine production of recoverable zinc,
.a zinc recovery efficiency of 83 percent and an average of 0.227 percent
cadmium contained in 60 percent zinc concentrates. Cadmium in imported
zinc ores is estimated at 6.208,000 Ib/year.1086
T7C1
In 1969, 12,646,000 Ib of cadmium were produced in the United States.
This figure includes cadmium metal and equivalent metal content of cadmium
sponge used directly in production of compounds. Cadmium potassium cyanide
was produced in very small quantity by City Chemical Company of Jersey City,
New Jersey—they are not producing it anymore. They were the only company
producing the compound and they only made about 5 or 10 Ib of the chemical
2219
per year. Individual production figures for the other cadmium compounds
discussed in this Profile Report are not available.
Manufacture
Cadmium Metal. Cadmium containing ore is mixed with sodium chloride
and coal or coke and heated in a sintering furnace. By subjecting the ore
to this chloridizing sinter, nearly complete elimination of cadmium as the
chloride can be attained and most of it can be recovered. The dust from the
roasters and the chloride fume are digested with sulfuric acid. Any lead
present is filtered off as the sulfate and metallic cadmium is precipitated
by the use of zinc dust. The remaining zinc chloride and sulfate solution
is returned to the sintering operation. The cadmium is purified by
distillation or electrolysis. 9
The purification of zinc sulfate solutions for lithopone or pigment
zinc sulfide manufacture produces some cadmium by zinc dust treatment.
Manufacturers of electrolytic zinc also produce considerable cadmium
during their purification of zinc solutions in a similar way.
-------
Some cadmium is volatilized in lead smelting and is caught in the
flue system, particularly in the bag houses. If present in sufficient
quantity, the dust is treated for cadmium recovery, usually by solution
pnog
in sulfuric acid, followed by zinc dust precipitation.
Large-scale commercial facilities for the manufacture of cadmium metal
include the following:0624
Amax; Blackwell, Oklahoma
Asarco; Denver, Colorado
Asarco; Corpus Christi, Texas
American Zinc Company; East St. Louis, Illinois
Anaconda; Great Falls, Montana
New Jersey Zinc; Depue, Illinois
Cadmium Chloride. The chloride may be made by dissolving the metal
in an aqueous solution of hydrogen chloride and evaporating in a stream of
hydrogen chloride gas. It may also be made by dissolving the oxide or
1433
carbonate in hydrochloric acid.
Cadmium chloride is produced by the following companies: 4
Allied Chemical Corporation; Marcus Hook, Pennsylvania
J. T. Baker Chemical Company ; Phillipsburg, New Jersey
Chemetron Corporation ; New Brunswick, New Jersey
The Harshaw Chemical Company ; Cleveland, Ohio
Mallinckrodt Chemical Works ; St. Louis, Missouri
Cadmium Nitrate. The nitrate is made by dissolving cadmium metal,
cadmium oxide, or cadmium carbonate in nitric acid and evaporating to
incipient crystallation. The anhydrous compound is made by dehydrating
the tetrahydrate.
183
-------
Cadmium nitrate is produced by the following companies:
Allied Chemical Corporation; Buffalo, New York
J. T. Baker Chemical Company; Phillipsburg, New Jersey
Chemetron Corporation; Cleveland, Ohio
The Harshaw Chemical Company; Glouscester City, New Jersey
Mallinckrodt Chemical toorks; St. Louiss Missouri
The Shepherd Chemical Company; Cincinnati, Ohio
Cadmium Oxide. Cadmium oxide may be made in one of several ways; the
pure metal may be distilled in a graphite retort and the vapor permitted
to react with air (since the nitride does not form under these conditions,
a pure oxide is obtained). This oxide varies in color and should be
calcined at low red heat to give an oxide of uniform color. Cadmium
carbonate and cadmium nitrate may be heated to their temperatures of
1433
decomposition to form the oxide.
Commercial facilities for the manufacture of cadmium oxide include
the following:0624
Allied Chemical Corporation; Marcus Hook, Pennsylvania
American Smelting and Refining Company; Denver, Colorado
J. T. Baker Chemical Company; Phillipsburg, New Jersey
Cadmium Potassium Cyanide. Cadmium potassium cyanide is made by
dissolving potassium cyanide in an aqueous solution of cadmium carbonate.
2219
The precipitate is collected and washed as crystals.
Cadmium Phosphate. Cadmium phosphate is prepared by interaction of
cadmium nitrate with potassium dihydrogen phosphate in the present of the
2039
proper amount of sodium hydroxide.
1'84
-------
Cadmium Sulfate. When cadmium metal, oxide, carbonate, or snlfide is
dissolved in solutions of sulfuric acid and cooled or evaporated, cadmium
sulfate (hydrate) crystallizes out. The anhydrous compound may be obtained
by the reaction of dimethyl sulfate on finely divided cadmium carbonate,
1433
nitrate, halides, or oxide.
Commercial facilities for the manufacture of cadmium sulfate include
the following:0624
Allied Chemical Corporation; Marcus Hook, Pennsylvania
American Smelting and Refining Company; Denver, Colorado
The Glidden Company; Baltimore Maryland
Uses
The chief use of cadmium metal in the United States is in electroplating
iron and steel. The industrial and commercial applications for cadmium plating
are numerous, including; components for aircraft, automobiles, electrical
and electronic apparatus, household applicances, radio and television sets,
hardware, and fasteners.
Cadmium metal is also used in pigments, plastics, alloys, and in making
nickel-cadmium batteries. These uses represent more than 90 percent of the
cadmium metal consumed in the United States in 1968. Smaller quantities,
totaling about 1.1 million Ib, were used in fungicides, nuclear energy
applications, phosphors for television tubes, photography, lithography,
process engraving, glass, X-ray screens, compounds for curing rubber, and
various other applications.
The principal application areas of the other five cadmium compounds
have been summarized by Athanassiadis (Table 1).
185
-------
TABLE I0624
APPLICATION AREAS OF CADMIUM COMPOUNDS
' Compound Uses
Cadmium Chloride In photography; in dyeing and calico printing; in the
vacuum tube industry; in manufacture of cadmium yellow;
special mirrors; as ice nucleating agent; lubricant; in
analysis of sulfides to absorb the hydrogen sulfide.
Cadmium Nitrate In making other cadmium salts; in photographic emulsions.
Cadmium Oxide In phosphors , semiconductors., manufacture of silver alloys,
glass; in storage battery electrodes; as nematocide; as
catalyst for organic reactions; in cadmium electroplating;
in ceramic glazes.
K
GD Cadmium Phosphate Similar uses to those of normal phosphate.
ff)
Cadmium Sulfate In electrodeposition of Cd9 Cu, and Ni; in phosphors; in
manufacture of standard cadmium elements.
-------
Sources and Types of Cadmium Wastes
The metals industry is the major source of emissions of cadmium into
the atmosphere. Cadmium dusts and fumes are produced in the extraction,
refining, and processing of metallic cadmium. Since cadmium is generally
produced as a by-product in the refining of other metals, such as zinc,
lead, and copper, plants refining these materials are sources of cadmium
emissions as well as of the basic metal. Also, because cadmium is present
in small quantities in the ores of these metals, cadmium emissions may
occur inadvertently in the refining of the basic metal.
The major sources of liquid and solid cadmium wastes have been found
to include the following: (1) the electroplating industry; (2) nickel-
cadmium battery manufacturers; (3) paint manufacturers; and (4) paint
residue left in old containers.
The total amount of cadmium wastes from the electroplating industry
is estimated to be 1.44 million Ib per year. Some of the typical cadmium
waste streams from the electroplating industry are:
(1) a liquid slurry containing 5 percent cadmium cyanide and
5 percent sodium cyanide in 10 percent aqueous sodium
hydroxide;
(2) a liquid containing 1.5 percent cadmium cyanide and 8.5 percent
sodium cyanide in 3 percent canister solution;
(3) a solid containing 3 percent cadmium oxide and 16 percent
cadmium metals with alkali carbonates;
(4) • 300 to 500 ppm cadmium chromate with aluminum alkaline salts,
organic cleaners, and 95 percent water.
Cadmium waste from battery manufacturing is generated mainly in the
production of sintered plate nickel-cadmium batteries. One form of the
waste is the sludge which settles in the bottom of the baths that are used
to impregnate the sintered plates with the active battery ingredients.
There is also a liquid waste that comes from the intentional or accidental
-------
discharge of the materials in the impregnation baths and from the rinsing
operation (where the sintered plates are rinsed of excess material). It
is estimated that there are 3,700 Ib of cadmium wastes generated in the
manufacture of nickel-cadmium batteries each year. A typical sludge from
the production of nickel-cadmium batteries may contain 4 percent cadmium
carbonate-hydroxide, 3 percent nickel carbonate, silica, other carbonates,
and trace metals (40 percent total solids). A typical impregnation bath
may be composed of 8 percent cadmium oxide, 0.6 percent nicklic oxide,
14 percent potassium hydroxide, and trace metals.
In the manufacture of solvent-based paints, sludges are generated
from both the washing system and the solvent recovery stills. The
combined solvent-based paint sludge is characterized by the following
composition: 4.5 percent inorganic pigment (excluding titanium dioxide),
8.5 percent titanium dioxide, 14.5 percent pigment extenders, 25.0 percent
binders, and 47.5 percent organic solvents. It is estimated that a total
of 5,100 Ib of cadmium are lost through 37 million Ib of solvent-based
paint sludges every year. The cadmium used in paints is usually chemically
combined with either sulfur or selenium in the form of cadmium sulfide,
cadmium selenide, or cadmium sulfoselenide.
The cadmium containing paint residues left in containers normally
discarded in municipal dumps constitute another source of selenium
waste. It is estimated that a total of 35,300 Ib of cadmium are lost as
paint residues every year.
Other sources of cadmium wastes as a contaminant in air or water may
include the following: (1) cadmium compound manufacturers; (2) manufacture
of cadmium-faced bearings; (3) casting of copper-cadmium alloys; (4)
smelting of scrap metal (containing cadmium); and (5) welding of cadmium-
plated metal parts.
188
-------
Physical and Chemical Properties
The physical and chemical properties of cadmium metal and the six
cadmium compounds are included in the attached worksheets.
2. TOXICOLOGY
The inhalation of fumes or dusts of cadmium primarily affects the
respiratory tract; the kidneys may also be affected. Even brief exposure
to high concentrations may result in pulmonary edema and death. Usually
the edema is not massive, with little pleural effusion. In fatal cases,
fatty degeneration of the liver and acute inflammatory changes in the
kidneys have been noted. Ingestion of cadmium results in a gastrointestinal
type of poisoning in its symptoms.
Inhalation of the dust or fumes may cause dryness of the throat,
coughing, headache, a sense of constriction in the chest, shortness of
breath (dyspnea) and vomiting. More severe exposure results in marked
lung changes, with persistent cough, pain in the chest, severe dyspnea
and prostration which may terminate fatally. X-ray changes are usually
similar to those seen in broncho-pneumonia. The urine is frequently dark.
These symptoms are usually delayed for some hours after exposure, and fatal
concentrations may be breathed without sufficient discomfort to warn the
workman to leave the exposure area. '
Ingestion of cadmium results in sudden nausea, salivation, vomiting,
diarrhea and abdominal pain. Symptoms begin almost immediately after
ingestion.
A yellow discoloration of the teeth has been reported in workers
exposed to cadmium. Cadmium oxide fumes can cause metal fume fever
resembling that caused by zinc oxide fumes.
189
-------
Two studies made by Pn'nci in the early 1950's indicate that
cadmium may not be as great an industrial hazard as is generally
ppii ppip
considered. ' Most of the deleterious effects of cadmium which
have been reported are the result of relatively brief exposures to high
concentrations of the substance. It is probable, therefore, that in
chronic exposures there is a rapid elimination of cadmium from the body
and that there is no cumulative effect. Princi observed and ran tests on
twenty men who, at times, were exposed to cadmium concentrations as high as
2212
31.30 milligrams per cubic meter of air in their work surroundings.
The tests revealed no serious chronic effects in the workmen from continuous
exposure to varying concentrations of cadmium (ranging from .04 to 31.3 mg
per cubic meter).
2210
The toxicity of cadmium toward fish was examined by Hi Hi bran.
His data indicated that cadmium can disrupt energy production by the
inhibition of oxygen uptake within the cellss and this disruption can occur
at relatively low levels (0.0033 micromoles/ml) and be of such severity as
to cause the deaths of fishes, particularly the bluegill.
Most quantitative data on the toxicity of cadmium toward fish are
based on specific salts of the metal. Expressed as cadmiums these data
indicated that the acute lethal level for fish varies from about 0.01 to
about 10 mg/liter depending on the test animal, the types of water,
temperature, and time of exposure. Cadmium acts synergistically with other
substances to increase toxicity. Concentrations of 0.03 mg/liter in
combination with 0.15 mg/liter of zinc causes mortality of very young salmon.
In a study of adult American Eastern oysters, the eight week TL value for
Cn/-
cadmium was 0.2 mg/liter and the fifteen week TL value was 0.1 mg/liter.
The relative oral LD5Q values to the rat are 88 mg/kg for cadmium
chloride and 72 mg/kg for cadmium oxide. The estimated LCrQ value for man
is 50 mg/cubic meter of air for cadmium oxide. The American Conference of
Governmental Industrial Hygienists (1971) recommended a Threshold Limit
Value (TLV) in air of 0.2 mg/cubic meter of air for all the cadmium
compounds discussed in this report, except for cadmium oxide. The TLV for
-------
cadmium oxide is 0.1 mg/cubic meter of air9225 The U.S. Public Health
Service established the permissible criteria for soluble cadmium in public
1752
water supplies as .01 mg/liter.
3. OTHER HAZARDS
The fire and explosive hazard of cadmium metal is moderate in the form
of dust when exposed to heat or flame or by chemical reaction with oxidizing
agents?7**-
Cadmium nitrate is an oxidizing material. In contact with easily
oxidizable substances it may react rapidly enough to cause ignition, violent
combustion or explosion.
Other than the toxic effects, the other cadmium compounds discussed
in this report present no further problems.
4. DEFINITION OF ADEQUATE WASTE MANAGEMENT
Handling, Storage, and Transportation
Care should be exercised in handling cadmium and its compounds because
of their high toxicity. Any material which comes in contact with the skin
should be removed with plenty of soap and water.
Cadmium nitrate should be stored in an area where it will be separated
from combustible, organic or other readily oxidizable materials. Any
spilled nitrate should be immediately removed and disposed of. All of the
cadmium compounds discussed in this report should be stored away from
foodstuffs, feeds, or any other material intended for consumption by humans
or animals.
Adequate procedures for the transportation of cadmium compounds have
0?7fi
been established by the Department of Transportation. Label requirements
as well as the maximum quantities permitted to be shipped in one outside
container, are also specified.
-------
Disposal/Reuse
The greater portion of cadmium and cadmium compounds present in air
and water waste streams can be removed and the cadmium recovered for its
value. With the current technology available, and considering the economic
factors involved,, it is not possible to remove all of the cadmium that
is discharged into waste streams. For these reasons, the safe disposal
of cadmium and cadmium compounds must still be defined in terms of the
recommended provisional limits:
Contaminant
In Air
Cadmium metal
(powder)
Cadmium chloride
Cadmium nitrate
Cadmium oxide
Cadmium potassium
cyanide
Cadmium phosphate
cadmium sulfate
Provisional Limit
.002 mg/M3
.002 mg/M3
.002 mg/M3
.001 mg/M3
.002 mg/M3
.002 mg/M3
.002 mg/M3
Basis for
Recommendation
.01 TLV
.01 TLV
.01 TLV
.01 TLV
.01 TLV
.01 TLV
.01 TLV
Contaminant
In Hater and Soil
Cadmium metal
(powder)
Cadmium chloride
Cadmium nitrate
Cadmium oxide
Cadmium potassium
cyanide
Cadmium phosphate
Cadmium Sulfate
Provisional Limit
.01 ppm (mg/1)
.01 ppm (mg/1)
.01 ppm (mg/1)
.01 ppm (mg/1)
.01 ppm (mg/1)
.01 ppm (mg/1)
.01 ppm (mg/1)
Basis for
Recommendation
Drinking water standard
Drinking water standard
Drinking water standard
Drinking water standard
Drinking water standard
Drinking water standard
Drinking water standard
132
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5. EVALUATION OF WASTE MANAGEMENT PRACTICES
Removal from Air
The metals industry is the major source of cadmium emissions to the
atmosphere. Cadmium dusts and fumes are produced in the extraction,
refining, and processing of metallic cadmium. More than 2 million Ib
of cadmium were released to the atmosphere by the metals industry in 1968.
Air pollution control procedures are employed at some metal refinery plants
in order to recover the valuable cadmium that would otherwise escape into
the atmosphere. Electrostatic precipitators, bag houses, and cyclones
are effectively used for abatement. However, little information has
been found on the specific application of these procedures for the purpose of
controlling cadmium air pollution. Procedures for recovering cadmium from
exhaust in a copper extraction plant collected significant quantities of
valuable cadmium, at the same time reducing local air pollution levels.
Removal from Water
Option No. 1 - Adsorption with Granular Activated-Carbon Bed^ The
effectiveness of granular activated-carbon beds to remove cadmium from
2218 181 "3
water has been investigated by Linstedt et al and Kuzin et al.
Linstedt found in his study that following passage through a column, filled
to a depth of 60 in. with 14 to 40 mesh granular activated-carbon, the
initial concentration of 50.5 ppb of cadmium was reduced to .6 ppb. This
represents a 98.8 percent removal of cadmium from the water. Kuzin's
laboratory investigation was principally directed towards the separation
of uranium from other metallic compounds in acetate solutions. It was
found in the same study, however, that activated carbon possessed a sorp-
tion capacity for soluble compounds of 1.9 mg/g carbon. Adsorption with
granular activated-carbon beds should be considered as one of the most
satisfactory methods for treating dilute cadmium wastes.
193
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Option No. 2 - Coagulation and Filtration. A pilot plant study by
2218
Lindstedt et al showed that coagulation, sedimentations, and filtration
could be used to remove about 95 percent of the cadmium in a water supply
from a secondary water treatment plant. The concentration of the cadmium
in the water before the coagulation process was 5.5 ppb. Coagulation
was achieved by slaking commercial-grade lime and pumping it into the
influent wastewater flow line. The pH was approximately 11 in the
coagulation unit. After lime addition, the wastewater entered a rapid-mix
line. The lime feed point was at the head of the line, and mixing was
achieved through turbulence of the flow. Slow mixing and settling
of the cadmium hydroxide preciptate were achieved in a fiber glass tank
equipped with four vertical baffles and a mixing blade. It can be concluded
that chemical coagulation followed by sand filtration is an adequate method
for removing cadmium from water.
Option No. 3 - Ion Exchange. Ion exchange can be used to remove
cadmium from dilute aqueous waste streams. Cadmium will behave much like
calcium and magnesium and can be removed from an aqueous waste stream by
either a sulfonic acid type cation exchange resin or a carboxylic weak
17QR
acid type resin, depending upon the pH of the stream. The effectiveness
of ion exchange to remove cadmium from water has been investigated by
2218
Linstedt et al. Linstedt found that the initial concentration of 50.5
ppb of cadmium in the water was reduced to .76 ppb. This represents a
98.5 percent removal of cadmium from the water. The major difficulty in
ion exchange operation is the critical dependence on flowrate. The ion
exchange system is designed to operate with a particular efficiency
at a certain set flow. Should this flow be exceeded, the efficiency for
adsorbing the cadmium ion decreases drastically causing the effluent to
exceed the permissible limit.
Option No. 4 - Reverse Osmosis. The effectiveness of reverse osmosis
1812
to remove cadmium from water has been investigated by Sourirajan.
Following passage of a cadmium waste stream through a porous cellulose
acetate membrane, it was found that the cadmium concentration was
reduced from 59.1 ppm to 11,2 ppm. This represents an 81 percent removal of
-------
cadmium from the water. With an effluent concentration of 11.2 ppm, the
reverse osmosis unit would have to be used in conjunction with some other
process (for example, adsorption with activated-carbon) to produce an
effluent with a permissible concentration of cadmium.
The other treatment processes for the removal of cadmium from water
that have been investigated include adsorption with zirconium phosphate,
2220
silica gel and charcoal. Akatsu et al demonstrated that the cadmium
ion was only slightly adsorbed by zirconium phosphate and charcoal and
not adsorbed at all by silica gel. These processes are therefore considered
as inadequate methods for treating dilute cadmium wastes.
Concentrated Cadmium Wastes
The only adequate method for the disposal of concentrated cadmium
wastes is coagulation with lime, then sedimentation followed by sand
filtration. The effluent from this process would probably have to be
treated further (for example, adsorption with activated-carbon or ion
exchange) to reduce the cadmium concentration to a level in compliance
with the U.S. Public Health Service recommendation for public drinking
water (.01 mg/liter). The cadmium hydroxide sludge produced in this process
can be dried and placed in an approved chemical landfill area of the Cali-
formia Class 1 type. Cadmium hydroxide is not very soluble (.00026g/100cc),
so contamination of water supplies from the landfill operation should not
be a problem. If the cadmium hydroxide sludge is relatively pure, it
can be dissolved in sulfuric acid and the cadmium metal recovered by zinc
dust precipitation (refer to section on Manufacture).
To summarize, the adequate treatment methods for dilute aqueous
cadmium wastes are: (1) activated-carbon bed absorption; (2) coagulation
and filtration; and (3) ion-exchange. For the concentrated cadmium
wastes, coagulation with lime followed by sedimentation and sand filtra-
tion is the only proven and adequate treatment method at present.
195
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6. APPLICABILITY TO NATIONAL DISPOSAL SITES
Cadmium and cadmium compounds are considered as candidate waste
stream constituents requiring National Disposal Site treatment for the
following reasons: (1) the extremely high degree of toxicity of all
cadmium compounds; (2) the nondegradable nature of the toxic cadmium
component of all cadmium compounds; (3) cadmium compounds are present
in sizable quantities as wastes from electroplating, paint manufacture,
battery manufacture, and the metals industry; (4) a significant portion
of cadmium wastes is contributed by small plating shops where treatment
is either technically or economically infeasible; and (5) the cadmium
hydroxide waste sludges resulting from the treatment of cadmium wastes
should be disposed of in California Class 1 type landfills only and are
not being adequately handled at present.
It is anticipated that disposal systems to handle both dilute and
concentrated cadmium wastes will be required at National Disposal Sites.
The processes recommended for the treatment of dilute cadmium wastes
at National Disposal sites are:
Process
Coagulation and
Filtration
Activated-Carbon
Beds
Ion Exchange
Order of Preference
First Choice
Second Choice
Third Choice
Remarks
Demonstrated technology;
can be effectively used
to remove both dilute and
concentrated cadmium wastes,
Demonstrated technology;
recommended unit operation
at National Disposal Sites.
Demonstrated technology;
critical dependence on
flowrate and economic
factors limit the feasi-
bility of this system.
136
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7. REFERENCES
0225. American Conference of Governmental Industrial Hygienists. Threshold
Threshold limit values for 1971. Occupational Hazards, p. 35-40,
Aug. 1971.
0278. Code of Federal Regulations. Title 49-transportation, parts 71 to 90.
(Revised as of Jan. 1, 1967). Washington, U.S. Government Printing
Office, 1967. 794 p.
0536. Water quality criteria. Report of the National Technical Advisory
Committee to the Secretary of the Interior. Apr. I, 1968. Washington,
Federal Water Pollution Control Administration. 234 p.
0624. Athanassiadis, Y. C. Air pollution aspects of cadmium and its
compounds. Report prepared for the National Air Pollution Control
Administration by Litton Systems, Inc., Bethesda, Maryland under
Contract PH-22-68-25. Washington, U.S. Government Printing Office,
1969. 84 p.
0766. Sax, N. I. Dangerous properties of industrial materials. 2d ed.,
New York. Reinhold Publishing Corp. 1957. 1,467 p.
1086. National inventory of sources and emissions-cadmium, nickel, and asbestos,
Report prepared for the National Air Pollution Control Administration
by W. E. Davis & Associates, Leawood, Kansas under contract CPA-22-
69-131. Washington, U.S. Government Printing Office, 1970, 44 p.
1433. Kirk-Othmer encyclopedia of chemical technology. 2d ed. 22 v. and suppl.
New York, Interscience Publishers, 1966. 899 p.
1751. Chemical statistics handbook. 7th ed. Washington, Manufacturing
Chemists Association, 1971. 475 p.
1752. Public Health Service. Drinking Water Standards, 1962. U.S.
Department Health, Education and Welfare, 1962. 61 p.
1795. Personal communication, C. T. Dickert, Rohm and Hass to D. Dal Porto,
TRW Systesm, May 16, 1972. Ion exchange applications to cadmium
waste treatment.
1812. Sourirajan, S. Separation of some inorganic salts in aqueous solution
by flow, under pressure through porous cellolose, acetate membranes.
Industrial and Engineering Chemistry Fundamentals, 3(3): 286-290,
Aug. 1964.
1813. Kuzin, A., V. P. Taushkanov, B. M. Leonov, and Y. A. Boganch.
Sorption of metals by SKT activated carbon from acetate
solutions. Journal of Applied Chemistry of the U.S.S.R.
39(2): 325-328, Feb. 1966.
197
-------
REFERENCES (CONTINUED)
2039. Sneed, M. C., R. C. Brasted. Comprehensive inorganic chemistry.
v. 4. New Jersey, D. Van Nostrand Company Inc., 1955. 193 p.
2210. Hiltibran, R. C. Effects of cadmium, zinc, manganese, and calcium
on oxygen and phosphate metabolism of bluegill liver mitochondria.
Journal of Water Pollution Control Federation. 43(5): 818-822,
May, 1971.
2211. Princi, F., E. F. Greever. Prolonged inhalation of cadmium.
Industrial Hygiene and Occupational Medicine. 1(651): 651-661. 1950.
2212. Princi, F. A study of industrial exposures to cadmium. Journal of
Industrial Hygiene and Technology. 29(5): 315-320, Sept. 1947.
2218. Linstedt, K. D., C. P. Houck, J. T. O'Conner. Trace element removals
in advanced wastewater treatment processes. Journal of Water
Pollution Control Federation. 43(7): 1507-1513, July, 1971.
2219. Personal communication, E. Colle, City Chemical Corporation to
D. Dal Porto, TRW Systems, Aug. 3, 1972. Cadmium potassium
cyanide manufacturing and production information.
2220. Akatsu, E., R. Ono, K. Tsukuechi, H. Uchiyama. Radiochemical
study of adsorption behavior of inorganic ions on zirconium
phosphate, silica gel and charcoal. Journal of Nuclear Science
and Technology. 2(4): 141-148, Apr. 1965.
198
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Cadmium (81), (82)
IUC Name
Common Names Cadmium
Structural Formula
Cd
Molecular Wt. 112.41
Density (Condensed)
@
Melting Pt. 320.9 C
Density (gas)_
Boiling Pt. 767
(?
Vapor Pressure (recommended 55 C and 20 C)
1 MM (3 394 C
(8
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower
Explosive Limits in Air (wt. %)
Solubility
Lower
Cold Water insolulbe
Others:
Hot Water insoluble
Upper_
Upper_
Ethanol
hot sufluric acid, ammonium nitrate
Acid, Base Properties
Highly Reactive with
Compatible with
Shipped in
ICC C1assification_
Commen ts
Coast Guard Classification
References (1) 0766
199
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HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Cadmium Chloride (83)
IUC Name
Structural Formula
Common Names
CdCl,
Molecular Wt. 183.32
Density (Condensed) 4.047
Melting Pt. 568 C
25 C Density (gas)_
Boiling Pt. 96° c
Vapor Pressure (recommended 55 C and 20 0
10 MM (8 656 C 100 MM g 797 C
Flash Point N/A Autolgnltlon Temp. N/A
Flammability Limits in Air (wt %) Lower
Explosive Limits in Air (wt. %)
Solubility
Cold Water 90 g/100 g @ 0 C
Others:
Lower
Upper_
Upper_
Hot Water 147 g/mg 0 100 C Ethanol slightly soluble
Acid, Base Properties
Highly Reactive with_
Compatible with
Shipped in
ICC Classification
Coast Guard Classification
Hexagonal, colorless crystals
References (1) 0766
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. H. Name Cadmium Oxide (85)
Structural Formula
IUC Name
Common Names Cadmium Oxide
(1) amorphous, brown crystals
(2) cubic, brown crystals
CdO
Molecular Wt. 1^8.41 Melting Pt. (1) 1.496C;(*)900C Boiling Pt. 15b9C
Density (Condensed) 6.95 & Density (gas)
8.15
Vapor Pressure (recommended 55 C and 20 C)
1MM @ 1000C &
Flash Point Autolgnition Temp._
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper
Solubility
Cold Water Insoluble Hot Water Insoluble Ethanol_
Others: Ammonia salts
Acid, Base Properties
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Coast Guard Classification_
Comments .
References (1) 0766
201
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Cadmium phosphate (86)
IUC Name Cadmium ortho-phosphate
Common Names
Structural Formula
Molecular Wt.
Density (Condensed)
527.19
Melting Pt. I5QQ C
Boiling Pt.
Density (gas)_
Vapor Pressure (recommended 55 C and 20 C)
Flash Point
Auto1gn1t1on Temp.
Flammability Limits in Air (wt X) Lower_
Explosive Limits in Air (wt. %) Lower
Upper.
Upper
Solubility
Cold Water insoluble
Others:
Hot Water
Ethanol
Acid, Base Properties
Highly Reactive with_
Compatible with
Shipped in_
ICC Classification
Commen ts
Coast Guard Classification
References (1)0766
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. H. Name Cadmium Nitrate (479)
Structural Formula
IUC Name
Common Names .
Cd(NO,}
3'2
Molecular Wt. 236.43 Melting Pt. -^ c Boiling Pt._
Density (Condensed)_ & Density (gas) @
Vapor Pressure (recommended 55 C and 20 Q)
G» ' 9 C
Flash Point • Autolgnition Temp.
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility
Cold Water 109g/1QOcc Hot Mater 3?6g/inn rr Ethanol Soluble
Others: Acids; ethyl acetate
Acid, Base Properties
Highly Reactive with_
Compatible with_
Shipped in
ICC Classification Coast Guard Classification
Commen ts , .
References (1) 1492
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. H. Name Cadmium Potassium Cyanide (480)
Structural Formula
IUC Name
Common Names Cadmium Potassium Cyanide
Cd(CN)./2KCN
Molecular Wt. 294.68 _ Melting Pt. _ Boiling Pt._
Density (Condensed) 1.847 _ @ __ Density (gas) _ i
Vapor Pressure (recommended 55 C and 20 C)
Flash Point _ Auto1gn1t1on Temp.
Flammability Limits in Air (wt %) Lower Upper_
Explosive Limits in Air (wt. %) Lower Upper_
Solubility
Cold Water 33.3 g/lOOCC Hot Water lOQg/100 CC Ethanol Insoluble
Others:
Acid, Base Properties
Highly Reactive with_
Compatible with_
Shipped in_
ICC Classification Coast Guard Classification
Comments When heated. meltsL to ^colorless limnrL sal idling to a grey, crystal 1ne mass
on cooling. _ ', _ ___
References (1) 1492
32E
-------
HAZARDOUS WASTES PROPERTIES
WORKSHEET
H. M. Name Cadmium Sulfate (481)
IUC Name
Common Names Cadmium Sulfate
Structural Formula
CdSO.
Molecular Wt. 208.46
Melting Pt. IQOOC
Boiling Pt._
Density (Condensed) 4.691 @ 20C 4C Density (gas)_
Vapor Pressure (recommended 55 C and 20 Q)
(3 @
Flash Point
Autoignition Temp.
Flammability Limits in Air (wt %) Lower_
Explosive Limits in Air (wt. %) Lower
Upper_
Upper_
Solubility
Cold Water 7S.5g/10QCC
Others:
Acid, Base Properties,
Hot Mater 60.8Q/1QOCC
Ethanol insoluble
Highly Reactive with_
Compatible with
Shipped in_
ICC Classification_
Comments
Coast Guard Classification
References (1)
205
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BIBLIOGRAPHIC DATA
SHEET
1. Report No.
EPA-670/2-73-053-f
3. Recipient's Accession No.
4. Title and subtitle Recommended Methods of Reduction, Neutralization,
Recovery, or Disposal of Hazardous Waste. Volume VI, National
Disposal Site Candidate Waste Stream Constituent Profile
Reports - Mercury, Arsenic, Chromium, and Cadmium Compounds
5. Report Date
Issuing date - Aug. 1973
6.
7.
R. S. Ottinger, J. L. Bl.umenthal, D. F. Dal Porto,
G. I. Gruber, M. J. Santy. and C. C. Shih
9. Performing Organization Name and Address
TRW Systems Group, One Spa.ce Park
Redondo Beach, California 90278
8- Performing Organization Rept.
No- 21485-6013-RU-OO
"lO. Project/Task/Work Unit No.
11. Contract/Grant No.
68-03-0089
12. Sponsoring Organization Name and Address
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. Type of Report & Period
Covered
Final
14.
15. Supplementary Notes
Volume VI of 16 volumes
16. Abstracts
This volume contains summary information and evaluation of waste management methods in
the form of Profile Reports for mercury, arsenic, chromium, and cadmium compounds.
These Profile Reports were prepared for either a particular hazardous waste stream
constituent or a group of related constituents. Each Profile Report contains a dis-
cussion of the general characteristics of the waste stream constituents, their toxicolog.
and other associated hazards, the definition of adequate management for the waste
material, an evaluation of the current waste management practices with regard to their
adequacy, and recommendation as to the nost appropriate processing methods available and
whether the waste material should be considered as a candidate for National Disposal,
Industrial Disposal, or Municipal Disposal.
17. Key Words and Document Analysis. 17a. Descriptors
Mercury Compounds
Arsenic Compounds
Chromium Compounds
Cadmium Compounds
National Disposal Site Candidate
Hazardous Wastes
17b. Identifiers/Open-Ended Terms
17c. COSATI Field/Group g6p. ggj. Q7B . 07C; g7E; ] 35 .
gA .
18. Availability Statement
Release to public.
- 206 -
19.. Security Class (This
Report)
UNCLASSIFIED
20. Security Class (This
Page
UNCLASSIFIED
21. Mo. of Pages
212
22. Price
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