United States Patent [19]
Coltrinari
[11 ]
[45j
4,029,741
June 14, 1977
9 Claims, 1 Drawing Figure
3,911,078 10/1975 Nadkami et at 423/87
Primary Examiner-G. R..Vertit
Assistant Examiner-Wayne A. Langel
Attorney, Agent, or Firm-Woodhams, Blanchard and
Flynn
A process is disclosed for separating antimony sulfides
from solutions comprising anitfftbny sulfides and arsenic
sulfides by subjecting the soiution to partial oxidation
within prescri,bed pH limits in order to oxidize
and precipitate a substantial portion of the antimony
sulfides while leaving substantially all of the arsenic
sulfides in solution.
[57] ABSTRACT
[56] References Cited
UNITED STATES PATENTS
2,348,360 5/1944 Reed 423/87
[54] RECOVERY OF ANTIMONY SULFIDES
[75] Inventor: Enzo L. Coltrinari, Arvada, Colo.
[73] Assignee: Tajima Roofing Co., Ltd., Tokyo,
Japan
[22] Filed: Mar. 1, 1976
(21] AppI. No.: 662,597
[52j U.S. CI 423/179; 423/87;
423/561 R
[51] Int. CI.2 , COlD 29/00
[58] Field of Search 423/87, 617, 561 R,
423/179,202
FEED
Noz5
TO LEACH
u.s. Patent June 14, 1977
FEED
4,029,741
!
02 AUTOCLAVE
OXIDATION
(NoOH) (PARTIAL)
FI L TRATI(;)N
II
II
N02S f As/Sb ISCRUBBER ::
H2S
SULFIDE f---H2SOf
t PRECIPITATION
NoOH
FILTER
H2O
AIR
EVAPORATION
8 ROAST S02
CARBON
FURNACE
N02S
TO LEACH
As/Sb ISb SULFIDEI
SULFIDES
5Na.SbS.+ 120. + 3H.0 ..... 2SboS. + NaSb(OH).+
7NaoS.0.
2
these values as antimony sulfides,thereby separating
these antimony values from the arsenic values in solution.
The thioantimonate compounds are reacted with
oxygen in order to produce insoluble antimony sulfides
5 and under some circumstances possibly minor amounts
of sodium hydroxyantimonate and sulfur, along with
soluble arsenic compound!" soluble sodium thiosulfate
and possibly some other non-sulfate sodium· salts.
Hence, the primary reaction is believed to be:
10
4,029,741
1
UTILITY OF THE INVENTION
SUMMARY OF THE INVENTION
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
BRIEF DESCRIPTION OF THE DRAWING
RECOVERY OF ANTIMONY SULFIDES
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the treating of
solutions to obtain antimony values, ~d more particularly
to recovering these antimony values. as antimony
sulfides. .
The Prior Art
Numerous ore bodies exist which possess· considerable
amounts of arsenic and antimony, and various
processes have been developed to recover these values.
These processes are primarily dependent upon the While these prOducts are representative of .the types
primary recovery mechanisms employed for recovering 15 known to. be f?rmed, the only produc~ of pnmary II?-
the more abundant mineral values in the ore bodies. portance IS antimony sulfide. The arsemc values remam
U.S. Pat. No. 2,348,360 to Reed discloses a method of in solution, permittiI}g the antimony sulfides to be rerecovering
minerals from ores comprising copper, his- cover~d by filtering or other conventional separation
muth, tin, mercury, antimony, arsenic, and others by techmques.. '.' .
leaching the ore and solublizing the various metal sul- 20 The starting .soluti?ns sUltab~e for. ada~tation to the
fide components, and then· sequentially oxidizing the pr?Cess of the mvention compnse thl?~timonatesand
various metal sulfides by means of air and sulfur diox- thloarsenates. These v.alues. ma~ eXist m ~ more. reide.
The metal sulfides are then recovered by means of duced form, such ~ thioantimomtes and ~o~emtes,
precipitation and flotation. and under the~e CIrcumstances the. solution 18 prefer-
U.S. Pat. No. 1,528,004 to Bassett describes a proc 25 ably treated Wl~ ele~ental sulfur m. order to convert
cess for recovering arsenic from complex arsenic sul- them t? the thioantimonate and thioarsenate. forms,
fides by roasting the ore in the presence ofsufficient air ~espectlvely. Th~ forms of the salts are not partiCUlarly
in order to oxidize the arsenic to arsenus oxide while Important, and mclude, for example, sodIUm, potasminimizing
any oxidation of the sulfur. . sium, ammonium,. and ?ther s~ar cations. For the
No process is known which is capable ofhighlyselec- 30 purposes of th~ disCUSSIO~ heremafter presented, the
tive recovery of antimony sulfides from solutions which sodium form will be descnbed.
comprise antimony sulfides and arsenic sulfides. The Other components may also be present in the soluprocess
of the present invention effects such a separa- tion, and while their presence will be reflected in the
tion, and thereby prOduces a valuable prOduct from final products, the antimony/arsenic separation may
what is generally considered to be a waste product 35 still be accomplished. The solution is preferably an
stream. aqueous solution.
Such a solution may be derived from a number of
sources, including from leached solutions of various
The process of the present invention separates and hydrometallurgical processes designed to prOduce such
prOduces relatively· pure antimony sulfides from the 40 primary metals as copper and nickel. Antimony and
hereinafter set forth starting materials, and these anti- arsenic often exist in minor amounts in various ore
mony sulfides can then be conventionally convertedto bodies, and hence when such primary values are reantimony
oxides, a basic raw material for many prod- moved from the solution, the process of the present
ucts. invention may be employed to separate the antimony
45 from the arsenic remaining in the solutions. Also, antimony
may be the primary element to be recovered
A process is disclosed for recovering antimony sul- from various ore bodies, and the process of the present
fides from aqueous solutions comprising thioantimony invention may be employed in the course of this recovcompounds
and thioarsenic· compounds by subjecting ery. The concentration of the starting materials is not
the solution to selective oxidation by reacting the thi- 50 particularly important to effect the desired separation,
oantimony compounds with sufficient oxygen so as to although the process may be conducted more effimaintain
a final solution e.m.f. and pH within pre- ciently if the thioantimonate concentration in the startscribed
limits in order to oxidize and precipitate a sub- ing solution is from about 20 to about 80 grams per
stantial portion of the thioantimony compounds as .liter, and preferably from about 40 to about 60 grams
antimony sulfides while leaving substantially all of the 55 per liter. Also the concentration of thioarsenate is not
thioarsenic compounds in solution. important as the purity of the final antimony sulfide
product may be controlled by recycling this product
stream back to the oxidation step until the desired
purity is attained. In order to obtain a final antimony
60 sulfide product possessing less than about 0.4% arsenic
and recovering 95% of the antimony in solution, the
ratio of the antimonate concentration to the arsenate
concentration should be maintained at at least about
about two to one.
65 The amount of oxygen consumed during the reaction
is critical to the antimony-arsenic separation. If insufficientoxygen
is provided, the antimony recovery will be
adversely affected. If too much oxygen is provided, all
The FIGURE illustrates a simple process flow diagram
for· the separation of antimony sulfide from antimony-
arsenic sulfide solutions, along with the regeneration
of sodium sulfide.
The process of the present invention· is primarily
concerned with the oxidation of thioantimonate compounds
in solution in order to selectively precipitate
4
EXAMPLE 5
EXAMPLE 4
EXAMPLE 3
EXAMPLES
EXAMPLE 1
Again, the procedure of example 1 was followed,
with an initial solution concentration of 75 grams per
liter antimony and 1.3 grams per liter arsenic, providingan
antimony/arsenicratio of 58:1. The temperature
65 was maintained at 115° C, the pressure at 75 psig, and
the resultant product pH was 7.6. 0.63 pounds of oxygen
were consumed per pound of antimony precipitated.
99% of the initial antimony in solution was pre-
The procedure of example 1 was again repeated with
an initial solution concentration of 76 grams per liter
antimony and 1.3 grams per liter arsenic, these values
existing as sodium thioantimonate and sodium thioarsenate,
respectively. The reaction conditions were 112°
C, 75 psig, and the resultant product pH was 9.8. 0.58
pounds of oxygen were consumed per pound of anti-
55 mony precipitated. 94% of the initial antimony was
precipitated and 5% of the initial arsenic was precipitated.
The fmal precipitate analysis was 63% antimony,
0.05% arsenic, 23% total sulfur, and 3.6% sodium.
The procedure of example number 1 was repeated
with an initial solution concentration of 40 grams per
liter antimony and 14.8 grams per liter arsenic, providing
an antimony/arsenic ration of 2.7/1. The reaction
temperature was maintained at 100° C, the pressure at
70 psig, and the resultant product pH was 9.5. 0.79
pounds of oxygen was permitted to be consumed per
pound of antimony precipitated. The precipitate analyzed
65% antimony, 0.17% arsenic, 25% total sulfur
30 and 1%sodium. 60% ofthe initial antimony was precipitated
and 0.4% of the arsenic was precipitated.
4,029,741
3
or part of the arsenic will also be oxidized, and the
antimony-arsenic separation will not be accomplished.
The preferred amount of oxygen consumed by the
reaction when the reactants are thioantimonate and An aqueous solution comprising sodium thioantithioarsenate
and there are no additional compounds 5 monate and sodium thioarsenate, having an antimony
competing for the oxygen is such that the fmal solution
e.m.f. is preferably from about 300 to about 500, more concentration of about 49 grams per liter and an arpreferably
from about 350 to about 430, and most senic concentration of 2.66 grams per liter (an antimopreferably
from about 390 to about 410 millivolts, ny/arsenic ration of about 18:1), was charged to an
measured with Platinum/saturated Calomel electrodes. 10 autoclave equipped with a turbine mixing device.Reac-
Based on this criteria, it is generally found that the tion temperature was maintained at 110° C and the
amount of oxygen consumed per pound of antimony reaction pressure was maintained at 45 psig. Oxygen
being treated is preferably from about 0.5 to about 1.5, was charged to the autoclave and permitted to be conmore
preferably from about 0.6 to about 0.9, and most su~ed at a rat~ C?f 0.57 pounds of oxygen per pound of
preferably from about 0.75 to about 0.85 pounds. 15 antm:lOny precIpItated. The resultant pH of~~ p~oduct
It is also critical to the effective operation of the solution was 10.4. The final product analySIS mdIcated
process that the pH be maintained within a range of that 92% of the antimony was precipitated, while only
about 7 to about 11, more preferably from about 7.5 to 2% of the arsenic was precipitated.
about 10, and most preferably from about 8 to 9. If the EXAMPLE 2
pH is permitted to fall below the minimum values, 20
precipitates other than antimony sulfides tend to be
produced, detrimentally affecting the product purity.
The solution pH may be maintained by adding, if necessary,
any suitable base, such as sodium hydroxide.
The temperature and pressure of the reaction are not 25
particularly important from the final product standpoint,
but do affect the rate of reaction. The reaction
does proceed at room temperature and atmospheric
pressure, although the rate is quite slow. Therefore, the
reaction temperature is preferably maintained from
about 25° C to about 200° C, more preferably from
about 500 C to about 1500 C, and most preferably from
about 90° C to about 120° C. The reaction pressure is
preferably maintained at at least about atmospheric Again the procedure of example 1 was repeated with
pressure, more preferably from about 20 to about 150, 35 an initial solution concentration of 37 grams per liter
and most preferably from about 40 to about 80 psig. antimony and 14.9 grams per liter arsenic, providing an
The reaction time is very fast, and within the pre- initial antimony/arsenic ratio of 2.5:1. The reaction
ferred temperature and pressure parameters. set forth pressure was maintained at 70 psig, the temperature at
above, the reaction time is not a factor. Hence, the 115° C, and the resultant product pH was about 9.3.
process may conveniently be conducted in either a 40 0.73 pounds of oxygen were permitted to be consumed
batch or continuous fashion. It is generally preferred to per pound of antimony precipitated. 82% of the initial
agitate the solution during the reaction in order to keep solution antimony was precipitated, while 0.6% of the
the oxygen well dispersed. arsenic was precipitated. The final precipitate analyzed
As was previously mentioned, the antimony product 64% antimony, 0.18% arsenic, 27% total sulfur and
stream may be redissolved and recycled in order to 45 0.8% sodium.
obtain an antimony sulfide product practically entirely
free of arsenic impurity.
Upon completion of the reaction, the prooduct
stream is filtered in order to separate the antimony
sulfide precipitate froom the product solution. The 50
antimony sulfide product is then of commercial value
and may be sold at this point, or futher conventionally
treated to produce antimony oxide, elemental antimony,
and other products. The product solution may
be further treated for the production of any other values
desired.
Sodium sulfide may be regenerated in conventional
fashion. One preferred technique is in accordance with
the scheme set forth in the FIGURE wherein the product
solution is treated with sulfuric acid to precipitate 60
the remainder of the arsenic and antimony sulfides and
produce hydrogen sulfide off-gas. The remaining acidified
solution is then evaporated to remove the water
and the remaining sodium salts are roasted in the presence
of air to produce sodium sulfate. This solium
sulfate is then reduced with a carbonaceous material in
a furnace to convert the sodium sulfate to sodium sulfide.
The sodium sulfide may then be recirculated.
5
4,029,741
6
Prod. Prec.
Assay %
Sb As
% of Total
Sb Left In
Soln.
Slurry ISb] in Prod.
pH Soln. (g./l.)
Slurry e.m.f.
(millivolts)
5
EXAMPLE 6
EXAMPLE 7
cipitated while 27% of the initial arsenic was precipitated.
The fmal product precipitate analyzed 66% antimony,
0.31% arsenic, 23% total sulfur and 2.5% sodium.
350 8.8 0.13 0.3 67 0.41
372 8.8 0.12 0.3 66 0.32
392 9.0 0.42 0.9 66 0.29
An aqueous solution comprising sodium thioanti- :i~ ::i i:~~ ::~ ~; g::i
monate and sodium thioarsenate having an antimony 42_8 9_.2 3_.6_8__~_8_.0 67__0_.0_91_
10 concentration of about 46 grams per liter and an' arsenic
concentration of about 16 grams per liter was What is claimed is:
continuously charged to 3 autoclave vessels connected 1. A process for recovering antimony sulfides from
an aqueous solution comprising thioantimony comin<
series, each of the vessels having a 3 liter capacity, at d d thi· d .. 15 poun s an oarsemc compoun s, compnsmg:
a flow rate of 5.1 liters per hour. The reaction tempera- subjecting the solution to partial oxidation by injectture
was maintained between about 1100 and 1150 C ing sufficient oxygen so as to maintain a final soluand
the reaction total pressure was maintained at 60 tion e.mJ. of from about 300 millivolts to about
psig. Oxygen was charged to the system at a rate of 0.81 500 millivolts,· measured with platinum/saturated
Calomel electrodes, while maintaining the product
pounds of oxygen per pound of antimony precipitated, 20 solution at a pH of from about 7 to about 11 in
resulting in a final solution e.m.f. of about 390 milli- order to oxidize and precipitate a substantial porvolts
measured with platinum/saturated Calomel elec- tion of the thioantimony compounds as antimony
trodes. The pH of the product solution was maintained sulfides while leaving substantially all of the thioarat
9.0, 99.1n70t 0 f the antt.mony m. the system was prec.l.p- 25 2 sTenhic compou.nfdsli'n so1lutiohn. . th thi .
. d d th . . al' . d' th • e process 0 c aIm w erem e oanttmony
ltate , an e precipItate an YSls m Icated at only compound is thioantimonate.
0.33% arsenic was present in the product precipitate. 3. The process of claim 2 wherein the thioantimonate
compound is sodium thioantimonate.
30 4. The process of claim 1 wherein the thioarsenic
An aqueous solution comprising sodium- thioanti- compound is thioarsenate.
monate and sodium thioarsenate having an antimony 5. The p~ocess. of cla!m 4 wherein the thioarsenate
. . compound IS sodIum thioarsenate.
con.centratlon of. about 46 grams per lIter an? an ar- 6. The process of claim 1 wherein the pH of the
semc concentration of about 16 grams per lIter was product solution is maintained from about 8 to about 9.
continuously charged to 3 autoclave vessels connected 35 7. The process of claim 1 wherein the reaction temin
series, each of the vessels having a 3 liter capacity, at perature is maintained from about 500 C to about 1500
a flow rate of about 5.1 liters per hour. The reaction C·S A I: " lfid fr
. . o' process lor recovenng anttmony su es om
temperature was mamtalned between about 110 and an aqueous solution comprising sodium thioantimonate
1150 C and the reaction total pressure was maintained 40 and sodium thioarsenate, comprising:
at 60 psig. Oxygen was charged to the system at varying subjecting the solution to partial oxidation by reactrates,
resulting in final solution e.mJ. values measured ~g sufficient oxygen so as to m~~ a final soluwith
platinum/saturated Calomel electrodes as given in tion e.~:f. of from about 3.00 mill~volts to about
. 500 millivolts, measured WIth platinum/saturated
the table belo.w. For ~ach of the gIVen e.~.f. values, the 45 Calomel electrodes, while maintaining the p~oduct
product solution pH IS set forth, along WIth the concen- solution at a pH of from about 7 to about II in
tration of antimony in the product solution, the per- order to oxidize and precipitate a substantial porcentage
of antimony in the product solution based tion of the sodium thioantimonate as antimony
upon the total amount of antimony in the feed solution, 50 s~des while.leavin~ substantially all ofthe sodium
. . . thloarsenate m solution.
and ~~ amo~nt ofanttmony and arsemc m the p~oduct 9. The process of claimS wherein the product solupreCIpItate,
gIven as a percentage of the total weIght of tion is treated for the recovery of sodium sulfide.
the precipitate: * * * * *
55
60
65
UNITED STATES PATENT OFFICE
CERTIFICATE OF CORRECTION
Patent No. 4,029,741 Dated June 14, 1977
Inventor (s ) E_n_z_o_L_o_C_o_l_t_r_i_n_a_r_i _
It is certified that error appears in the above-identified patent
and that said Letters Patent are hereby corrected as shown below:
On the first page, in item "[73]", the correct assignee is
Equity Mining Corporation, Vancouver, British Columbia, Canada °
~igncd and 5calcd this
Twenty-second .Day of November 1977
[SEAL]
Attest:
RUTH C. MASON
Attest;ng Officer
LUTRELLE F. PARKER
Act;ng Commissioner of Patents and Trademarks
;�7Mfr0�(D�-family: HiddenHorzOCR'>6. The process of claim 5 in which the silicon tetrachloride
is introduced into the coating chamber in a gas
stream.
7. The process of claim 6 in which the gas stream is
an air stream.
8. The process of claim 1 in which the coal particles
are coated in accordance with the following process
steps:
a. introducing coal particles into a coating chamber;
b. introducing silicon tetrachloride into the chamber
under conditions that will promote its combination
with water either introduced into the chamber in a
separate stream or derived from the coal itself to 35
40
45
50
55
60
65
;marg�4Pot0�(D�t;line-height: normal;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none'>injected into the jacket for the heating cycle. The speed
of the agitator is that at which the particles are kept in
suspension and a homogeneous slurry is maintained. At
This example shows the process is effective for zinc
concentrates and shows the deleterious effect of zinc
and iron ions on yield.
EXAMPLE VII (See Example III)
About 270 grams of a concentrate produced by the
oxidation of chalcopyrite-containing sulfur 48%,chalcopyrite
12%, pyrite and other minerals 40%, was 50
washed, slurried in I liter of water and held at 135°C ±
5° for the times shown. The slurry was cooled and
screened on a 100 mesh U.S. Standard screen.
Test I Test 2 Test 3
Additive 2 gm NaOH 2 gm NaOH 2 gm NaOH
(.74 gm/lOO gm of (.74 gm/lOO gm of (.74 gm/lOO gm
feed) feed) of feed)
Time 30 min. 60 min. 235 min.
Product
(o/c sulfur) 88.5 90.9 86.7
Yield (%) 23.0 19.0 59.0
This example shows that while a ,small amount of 65
coalescence occurs very quickly that times in excess of
I hour are necessary to obtain a high degree of coale~cence.
the end of the heating cycle, steam was shut off, cooling
water was admitted to the jacket, the autoclave cooled
down, and when the temperature dropped below 80°C
the' agitator was slowed down, the bottom valve opened
and the autoclave 'dischargedtoa screen. The sulfur
3,939,256
9
product was removed as the oversize + 65 .mesh, and
the fine materials or the tailings proceeded on to a
thickener. The sulfur product averaged around 96%
elemental sulfur with a recovery of over 85%. The
particles were greenish-yellow in color and irregularly 5
shaped.
What is claimed is:
l. A process for the recovery of elemental sulfur
from mixtures in which it is present with soluble calcium
compound impurities which comprises: 10
a. contacting the mixture with water to solubilize
calcium ions;
b. separating the solids content of the treated mixture
from the liquid content and washing the solids
15
20
25
30
35
40
45
50
55
60
65
10
content to remove said solubilized calcium ions
from the solids content;
c. forming a water slurry of said solids content;
d. adding to the slurry a surface modifying additive
selected from the group consisting of alkali metal
hydroxides, alkali metal carbonates, and mixtures
thereof to produce an alkaline slurry pH of at least
about 9;
e. heating the slurry to at least the melting point of
sulfur for a period sufficient to coalesce substantially
all of the sulfur particles, and
f. recovering the coalesced sulfur from the slurry.
* * * * *