CA2063031C - Process for upgrading copper sulphide residues containing nickel and arsenic - Google Patents
Process for upgrading copper sulphide residues containing nickel and arsenicInfo
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- CA2063031C CA2063031C CA 2063031 CA2063031A CA2063031C CA 2063031 C CA2063031 C CA 2063031C CA 2063031 CA2063031 CA 2063031 CA 2063031 A CA2063031 A CA 2063031A CA 2063031 C CA2063031 C CA 2063031C
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- copper
- nickel
- leach
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- residue
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
A process is disclosed for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic. Finely divided nickel-copper matte is leached in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure and at a minimum temperature of about 80°C to selectively leach nickel from the matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5, preferably about 6.5, and to produce a copper-rich sulphide residue. The copper-rich sulphide residue is separated from the nickel sulphate solution and leached in a closed reaction vessel at a minimum temperature of about 120°C under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of copper and sulphuric acid to provide a terminal concentration of at least about 2 g/L Cu2+ and at least about 20 g/L sulphuric acid to produce a nickel sulphate solution containing any iron and arsenic and to produce a low nickel copper sulphide product essentially free of iron and arsenic.
Description
-"' 2~303~ ~
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a process for treating nickel-copper mattes for the recovery of copper and nickel values. More particularly, this invention pertains to a process for producing a copper sulphide concentrate containing less than 1% nickel and less than 1% arsenic, suitable for treatment by con~entional copper smelting and refining proces~es.
De5CriPtiOIl of Related Art Prior art leach processes are disclosed in U.S.
Patent No. 4,323,541 granted April 6, 1982 to Outokumpu Oy and U.S. Patent No. 3,616,331 granted October 26, 1971 to International Nickel Company Inc.
U.S. Patent No. 4,323,541 discloses leaching a finely-ground nickel-copper matte using an acid solution at a ;~ temperature of approximately 800C and under oxidizing conditions in order to produce a nickel sulphate solution and a nickel-copper sulphide residue, which is separated from the solution. Thereafter the nickel-copper sulphide residue is leached using acid in an autoclave at a minimum temperature of llOoC and under oxidizing conditions in order to produce an additional quantity of nickel sulphate solution and a copper sulphide precipitate.
The process disclosed in U.';. Patent No. 4,823,541 was applied to a nickel-copper matt6! to produce a copper sulphide residue sample containing nickel sulphide, nickel oxide, iron and arsenic ~45.5% Cu, 13.7% Ni, 2.5% Fe, 2.6%
As and 17.6% S), by leaching the matte under oxidizing conditions in aqueous sulphuric acid solution at atmospheric pressure to extract the major portion of the nickel and a minor portion of the copper, leaving the copper containing residue. This residue wa~ leached in a solution containing 3 g/L Cu and 33 g/L ~ SO4 in a 2.5L
autoclave for 120 minutes, under an air pressure of 150 kPa, with a vent rate of l L/min. The leach residue - ., :,. :
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a process for treating nickel-copper mattes for the recovery of copper and nickel values. More particularly, this invention pertains to a process for producing a copper sulphide concentrate containing less than 1% nickel and less than 1% arsenic, suitable for treatment by con~entional copper smelting and refining proces~es.
De5CriPtiOIl of Related Art Prior art leach processes are disclosed in U.S.
Patent No. 4,323,541 granted April 6, 1982 to Outokumpu Oy and U.S. Patent No. 3,616,331 granted October 26, 1971 to International Nickel Company Inc.
U.S. Patent No. 4,323,541 discloses leaching a finely-ground nickel-copper matte using an acid solution at a ;~ temperature of approximately 800C and under oxidizing conditions in order to produce a nickel sulphate solution and a nickel-copper sulphide residue, which is separated from the solution. Thereafter the nickel-copper sulphide residue is leached using acid in an autoclave at a minimum temperature of llOoC and under oxidizing conditions in order to produce an additional quantity of nickel sulphate solution and a copper sulphide precipitate.
The process disclosed in U.';. Patent No. 4,823,541 was applied to a nickel-copper matt6! to produce a copper sulphide residue sample containing nickel sulphide, nickel oxide, iron and arsenic ~45.5% Cu, 13.7% Ni, 2.5% Fe, 2.6%
As and 17.6% S), by leaching the matte under oxidizing conditions in aqueous sulphuric acid solution at atmospheric pressure to extract the major portion of the nickel and a minor portion of the copper, leaving the copper containing residue. This residue wa~ leached in a solution containing 3 g/L Cu and 33 g/L ~ SO4 in a 2.5L
autoclave for 120 minutes, under an air pressure of 150 kPa, with a vent rate of l L/min. The leach residue - ., :,. :
2~3~3~
contained 59% Cu, 2.3% Ni, 3.0% Fe, 4.5% As and 20.7% S.
The leach solution contained 10 g/L Cu, 10 g/L Ni and 14 g/L ~ S04 . The Cu:Ni and Cu:As ratios in the residue were 26:1 and 13:1 respectively. The Ni:Cu ratio in the solution was 1:1.
U.S. Patent No. 3,616,331 shows a two-stage process ~or the treatment of a nickel-containing copper sulphide material which contains copper and sulphur in ratios of at least 3.5:1~preferably 4:1 and 10:1, and controlled amounts of iron. This material is leached with an acidic aqueous solution containing copper sulphate in amounts at least stoichiometrically e~uivalent to the nickel, iron and cobalt contained in the starting material, and sufficient sulphuric acid to maintain a pH below 5. Advantageously, the copper sulphate solution contains a stoichiometric excess of copper sulphate of up to about 20~ in order to ensure maximum dissolution of the nickel, iron and cobalt as sulphates. The leaching operation is conducted at a temperature between about lOOoC and 2500C under the pressure generated at these temperatures. The residue obtained fro~ this leaching operation contains substantially all the copper in the starting material as copper sulphide and cement copper and is substantially free of iron. After filtration, the filtrate is treated to recover nickel, and the residue is treated to recover copper and sulphur in a second pressure leaching step (which does not pertain to this application~. ' The first step of the two-stage process disclosed in U.S. Patent No. 3,616,331 was applied to a copper ' sulphide residue sample containing nickel oxide (55.8% Cu, 12.8~ Ni, 19.7% S) recovered from a nickel copper matte by the atmospheric pressure sulphuric acid leach described above in connection with U.S. Patent No. 4,823,541. The re~idue was contacted with a solution containing 84 g/L Cu and 3 g/L ~ S04 in a laboratory batch autoclave at 2000C
for 60 minutes. The leach residue was separated from the :
, ~
. , -- 2~S~
solution by filtration. The residue contained 74.6% Cu, 1.6% Ni and 19.4% S. A similar leach test using a solution containing 50 g/L Cu and 5 g/L ~ S04 at 150~C for 60 minutes produced a residue containing 68% Cu, 7.9% Ni and 19.1% S.
The application of the prior art processes to the above-mentioned samples resulted in copper sulphide residues that contained such high percentages of nickel and arsenic that the copper sulphide residues could not be fed to the converter stage of a copper smelting process without further processing to remove nickel and arsenic. It is therefore an object of the present invention to eliminate such further processing and to thereby eliminate costs associated with that further processing by reducing the quantities of nickel and arsenic present in the copper sulphide residues.
The pressure leaching of nickel-copper mattes and copper sulphides residues under oxidizing conditions promotes oxidation of sulphur to sulphate which must subsequently be disposed of such as by neutralizing with caustic soda at considerable expense. It is therefore another object of the present invention to ln1 tze sulphate production by obviating the use of pressure oxidizing leaches.
SUMMARY OF THE IN~ L~ON
In its broad aspect, the process of the present invention is directed to the leaching of granular nickel-copper matte in an acidic solution under oxidizing conditions at atmospheric pressure with a deficiency of acid to produce a nickel sulphate solution and a copper-rich ~ulphide residue containing readily acid-soluble copper followed by the leaching of the copper-rich sulphide residue in an acidic solution under non-oxidizing conditions under elevated temperature and pressure to produce a final nickel sulphate solution containing a predetermined minimum of soluble copper and an excess of :: -::
.
.~ ,: :. .
2 ~ 3 ~
acid to maintain any iron and arsenic in solution while producing a low nickel copper sulphide product essentially free of iron and arsenic.
We have found that conducting the acid leach of the copper-nickel matte under oxidizing conditions with a surplus of matte in the primary stage of a two-stage oxidizing leach for a deficiency of acid and with a controlled amount of acid in the second stage of the two-stage oxidizing leach for a deficiency of acid results in the hydrolysis of metal sulphates, principally copper sulphate, with precipitation of basic copper sulphate lantlerite). The ~asic copper sulphate precipitate is readily acid soluble at low temperatures and, under the non-oxidizing conditions of a pressure leach with an excess of acid, provides an effective source of Cu2' which displaces Ni and ~s from the copper sulphide residue and maintains said Ni, As as well as Fe in the final nickel sulphate solution to produce a copper sulphide residue essentially free of arsenic and iron and low in nickel content.
More particularly, the process of the present invention is directed to the leaching of granular nickel-copper matte in an acidic solution under oxidizing conditions at a temperature of about 800C under atmospherlc pressure to produce a nickel sulphate solution and a copper-rich sulphide residue followed by leaching of the copper-rich sulphide residue in an acidic solution containing an effective amount of copper and sulphuric acid to provide terminal concentrations of at least 2 g/L Cu2+
and at least 20 g/L sulphuric acid in a nickel sulphate solution containing any arsenic and iron in the copper-rich sulphide residue from the oxidizing leach and to produce a ~inal copper sulphide residue product essentially free of arsenic and iron and with a low nickel content. These terminal concentrations are provided by ensuring at least a 3:1 copper to sulphur weight ratio, preferably in the range .".~
2~'3~
o~ 3:1 to 4:1 copper to sulphur weight ratio, in the copper sulphide residue product Prom the non-oxidizing leach.
The oxidizing acid leach of the matte under atmospheric pressure with a deficiency of acid preferably is carried out in two stages; a primary leach stage with an excess of matte feed whereby up to about 50% of the nickel is dissolved and essentially all the copper is precipitated as copper sulphide and basic copper sulphate, and a secondary leach stage with a controlled amount of acid whereby most of the re ~; n i ng nickel and a portion of the copper are dissolved and a predetermined effective amount of copper sulphate is hydrolyzed and precipitated as basic copper sulphate. A final pH in the range of 4.0 to 6.5, preferably about 6.5 in the first stage and about 4.5 in the second stage in the acid solutions containing nickel sulphate in the two leaches, ensures adequate basic copper sulphate as a supply of Cu2' for th~ subsequent non-oxidizing acid leach.
BRIEF DESCRIPTION OF THE DRAWING
The process of the invention will be described with reference to the drawing which is a schematic flowsheet illustrating a preferred embodimen~ thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawlng, numeral 10 depicts the oxidizing atmospheric leaoh of the process of the invention which preferably comprises a primary stage oxidizing leach 12 (cementation leach) and a secondary stage oxidizing leach 14 Icopper leach). Matte ground to a particle size of less than about 20 microns and having a typical composition by weight of 68% Ni, 23% Cu, 2% As and 6% S, with a Cu:S ratio in the range of 2:1 to 4:1, usually in the range of about 3:1 to 4:1, is fed to primary stage oxidizing leach 12 for reaction in an aqueous sulphuric acid solution, preferably recycle leach solution from secondary stage oxidi~ing leach 14. The solution is maintained at a temperature in the range of about 800C to ... .. . . . :, 2 ~ 3 ~
the boiling point of the solution, preferably at about 800C. Air and/or oxygen is sparged into the solution which is under atmospheric pressure and the solution agitated for extraction of about 45-50% of the nickel without oxidizing the sulphur. An excess of matte is provided relative to the acid to ensure precipitation of the copper as metallic copper and copper sulphide, normally as Cu2 S, ~ with production of basic copper sulphate. The residue also contains copper oxide, C~ O formed by oxidation of metallic copper as well as an unreacted metallic nickel Ni3 S2 and NiO. A final pH in the range of 4.0 to 6.5 preferably about 6.5, is attained.
The leach solution with up to 90 g/L Ni and containing 5 to 10 mg/L of each of copper and iron and 10 g/L ~ S04, iS passed to cobalt separation and nickel electrowinning 18.
The nickel-copper sulphide residue is separated from the leach solution in liquid-solid separator 2G and passed to secondary stage oxidizing leach 14 under similar temperature and pressure conditions as those in the primary stage leach 12 and reacted with a controlled amount of sulphuric acid-containing nickel sulphate solution comprised of 50 g/L Ni and 50 g/L ~ S04 at a sulphuric acid to solids weight ratio in the range of 0.3:l to 0.6:1, preferably about 0.5:1. The qua~ntity o~ acid thus is controlled to provide an acid deficiency at termination of the leach represented by a pH in the range of ~.0 to 6.5, preferably about 4.5, to leach most of the r.c--in~ng nickel and to produce a leach residue of which about 60~ by weight is in a readily acid soluble form such as basic copper and nickel sulphates and ferric arsenate. The acid balance in the circuit is maintained by diverting that portion of the available nickel anolyte which is not used in the secondary oxidizing leach 14 or the non-oxidizing pressure leach 24, directly to the primary leach 12.
The leach solution containing about 70-80 g/L Ni , . ..
3 ~
and 10 g/L Cu at a pH of about 4.5 is recycled to primary stage oxidizing leach 12. The copper-rich sulphide residue comprised of copper and nickel sulphides and nickel oxide, together with the acid soluble ba~ic copper sulphate (CuSO4 2Cu(OH) 2 ~, basic nickel sulphate and ferric arsenate, is separated ~rom the leach solution by liquid-solid separator 22 and fed to an autoclave for a non-oxidizing leach 24 with a sulphuric acid containing nickel sulphate solution having about 50g~L Ni and 50 g/L ~ SO4 at an acid to solids weight ratio in the range of 0.3:1 to 0.8:1, preferably about 0.5:1 to 0.7:1. The non-oxidizing atmosphere of this leach is maintained by sparging steam or steam containing nitrogen into the autoclave to maintain the solution temperature at above 1200C, preferably in the range of 140~ to 160~C. The basic metal sulphate precipitate and the ferric arsenate are redissolved in the acid solution under the non-oxidizing conditions and the Ni, Fe and As are maintained in solution due to the pre3ence of CuZ+ from the basic copper sulphate.
The copper sulphide residue having low nickel, arsenic and iron contents is separated from the leach solution by liquid-solid separator 26 and can be fed to conventional copper smelting and refining.
The leach solution can be recycled to secondary Qtage oxldizing leach 14 or treiated in iron-arsenic precipitation step 28 in which the solution is heated to about 1500C under oxidizing conditions for precipitation of the iro~ and arsenic as ferric arsenate. The ferric arsenate precipitate is separated from the leach solution by liquid-solid separator 30 for disposal and the solution recycled to secondary oxidizing leach 14.
The process of the invention will now be described with reference to the following non-limitative examples:
EXA~PLE 1 The same nickel oxide-containing copper sulphide residue as was produced by the atmo~pheric oxidizing leach discussed above in connection with U.S. Patent No.
3,616,331, was contacted with a solution containing 50 g/L
.
: : . -~ ' l ' ' , . . ' ' ~ : ' Cu and 50g/L ~ S04 at 1500C for 120 minutes under non-oxidizing conditions. Samples of residue were taken for analysis after 60 and 120 minutes of leaching. After 60 minutes, the leach residue contained 72.4% Cu, 2.5% Ni and 22.3% S, and after 120 minutes it analyzed 75% Cu, 0.9% Ni and 21.3%S This example demonstrates that by increasing the acid concentration from less than 15 g/L ~ S0~ to 50 g/L in the leach solution, nickel oxide and nickel sulphide can be leached from the copper sulphide residue at a much lower temperature (1500C) than is required using the U.S.
Patent No. 3,616,331 process conditions (2000C). This will obviously require much less energy and the milder conditions of temperature and pressure will permit the use of less expensive materials of construction.
The same nickel oxide-containing copper sulphide residue as was produced by the atmospheric oxidizing leach discussed above in connection with U.S. Patent No.
contained 59% Cu, 2.3% Ni, 3.0% Fe, 4.5% As and 20.7% S.
The leach solution contained 10 g/L Cu, 10 g/L Ni and 14 g/L ~ S04 . The Cu:Ni and Cu:As ratios in the residue were 26:1 and 13:1 respectively. The Ni:Cu ratio in the solution was 1:1.
U.S. Patent No. 3,616,331 shows a two-stage process ~or the treatment of a nickel-containing copper sulphide material which contains copper and sulphur in ratios of at least 3.5:1~preferably 4:1 and 10:1, and controlled amounts of iron. This material is leached with an acidic aqueous solution containing copper sulphate in amounts at least stoichiometrically e~uivalent to the nickel, iron and cobalt contained in the starting material, and sufficient sulphuric acid to maintain a pH below 5. Advantageously, the copper sulphate solution contains a stoichiometric excess of copper sulphate of up to about 20~ in order to ensure maximum dissolution of the nickel, iron and cobalt as sulphates. The leaching operation is conducted at a temperature between about lOOoC and 2500C under the pressure generated at these temperatures. The residue obtained fro~ this leaching operation contains substantially all the copper in the starting material as copper sulphide and cement copper and is substantially free of iron. After filtration, the filtrate is treated to recover nickel, and the residue is treated to recover copper and sulphur in a second pressure leaching step (which does not pertain to this application~. ' The first step of the two-stage process disclosed in U.S. Patent No. 3,616,331 was applied to a copper ' sulphide residue sample containing nickel oxide (55.8% Cu, 12.8~ Ni, 19.7% S) recovered from a nickel copper matte by the atmospheric pressure sulphuric acid leach described above in connection with U.S. Patent No. 4,823,541. The re~idue was contacted with a solution containing 84 g/L Cu and 3 g/L ~ S04 in a laboratory batch autoclave at 2000C
for 60 minutes. The leach residue was separated from the :
, ~
. , -- 2~S~
solution by filtration. The residue contained 74.6% Cu, 1.6% Ni and 19.4% S. A similar leach test using a solution containing 50 g/L Cu and 5 g/L ~ S04 at 150~C for 60 minutes produced a residue containing 68% Cu, 7.9% Ni and 19.1% S.
The application of the prior art processes to the above-mentioned samples resulted in copper sulphide residues that contained such high percentages of nickel and arsenic that the copper sulphide residues could not be fed to the converter stage of a copper smelting process without further processing to remove nickel and arsenic. It is therefore an object of the present invention to eliminate such further processing and to thereby eliminate costs associated with that further processing by reducing the quantities of nickel and arsenic present in the copper sulphide residues.
The pressure leaching of nickel-copper mattes and copper sulphides residues under oxidizing conditions promotes oxidation of sulphur to sulphate which must subsequently be disposed of such as by neutralizing with caustic soda at considerable expense. It is therefore another object of the present invention to ln1 tze sulphate production by obviating the use of pressure oxidizing leaches.
SUMMARY OF THE IN~ L~ON
In its broad aspect, the process of the present invention is directed to the leaching of granular nickel-copper matte in an acidic solution under oxidizing conditions at atmospheric pressure with a deficiency of acid to produce a nickel sulphate solution and a copper-rich ~ulphide residue containing readily acid-soluble copper followed by the leaching of the copper-rich sulphide residue in an acidic solution under non-oxidizing conditions under elevated temperature and pressure to produce a final nickel sulphate solution containing a predetermined minimum of soluble copper and an excess of :: -::
.
.~ ,: :. .
2 ~ 3 ~
acid to maintain any iron and arsenic in solution while producing a low nickel copper sulphide product essentially free of iron and arsenic.
We have found that conducting the acid leach of the copper-nickel matte under oxidizing conditions with a surplus of matte in the primary stage of a two-stage oxidizing leach for a deficiency of acid and with a controlled amount of acid in the second stage of the two-stage oxidizing leach for a deficiency of acid results in the hydrolysis of metal sulphates, principally copper sulphate, with precipitation of basic copper sulphate lantlerite). The ~asic copper sulphate precipitate is readily acid soluble at low temperatures and, under the non-oxidizing conditions of a pressure leach with an excess of acid, provides an effective source of Cu2' which displaces Ni and ~s from the copper sulphide residue and maintains said Ni, As as well as Fe in the final nickel sulphate solution to produce a copper sulphide residue essentially free of arsenic and iron and low in nickel content.
More particularly, the process of the present invention is directed to the leaching of granular nickel-copper matte in an acidic solution under oxidizing conditions at a temperature of about 800C under atmospherlc pressure to produce a nickel sulphate solution and a copper-rich sulphide residue followed by leaching of the copper-rich sulphide residue in an acidic solution containing an effective amount of copper and sulphuric acid to provide terminal concentrations of at least 2 g/L Cu2+
and at least 20 g/L sulphuric acid in a nickel sulphate solution containing any arsenic and iron in the copper-rich sulphide residue from the oxidizing leach and to produce a ~inal copper sulphide residue product essentially free of arsenic and iron and with a low nickel content. These terminal concentrations are provided by ensuring at least a 3:1 copper to sulphur weight ratio, preferably in the range .".~
2~'3~
o~ 3:1 to 4:1 copper to sulphur weight ratio, in the copper sulphide residue product Prom the non-oxidizing leach.
The oxidizing acid leach of the matte under atmospheric pressure with a deficiency of acid preferably is carried out in two stages; a primary leach stage with an excess of matte feed whereby up to about 50% of the nickel is dissolved and essentially all the copper is precipitated as copper sulphide and basic copper sulphate, and a secondary leach stage with a controlled amount of acid whereby most of the re ~; n i ng nickel and a portion of the copper are dissolved and a predetermined effective amount of copper sulphate is hydrolyzed and precipitated as basic copper sulphate. A final pH in the range of 4.0 to 6.5, preferably about 6.5 in the first stage and about 4.5 in the second stage in the acid solutions containing nickel sulphate in the two leaches, ensures adequate basic copper sulphate as a supply of Cu2' for th~ subsequent non-oxidizing acid leach.
BRIEF DESCRIPTION OF THE DRAWING
The process of the invention will be described with reference to the drawing which is a schematic flowsheet illustrating a preferred embodimen~ thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawlng, numeral 10 depicts the oxidizing atmospheric leaoh of the process of the invention which preferably comprises a primary stage oxidizing leach 12 (cementation leach) and a secondary stage oxidizing leach 14 Icopper leach). Matte ground to a particle size of less than about 20 microns and having a typical composition by weight of 68% Ni, 23% Cu, 2% As and 6% S, with a Cu:S ratio in the range of 2:1 to 4:1, usually in the range of about 3:1 to 4:1, is fed to primary stage oxidizing leach 12 for reaction in an aqueous sulphuric acid solution, preferably recycle leach solution from secondary stage oxidi~ing leach 14. The solution is maintained at a temperature in the range of about 800C to ... .. . . . :, 2 ~ 3 ~
the boiling point of the solution, preferably at about 800C. Air and/or oxygen is sparged into the solution which is under atmospheric pressure and the solution agitated for extraction of about 45-50% of the nickel without oxidizing the sulphur. An excess of matte is provided relative to the acid to ensure precipitation of the copper as metallic copper and copper sulphide, normally as Cu2 S, ~ with production of basic copper sulphate. The residue also contains copper oxide, C~ O formed by oxidation of metallic copper as well as an unreacted metallic nickel Ni3 S2 and NiO. A final pH in the range of 4.0 to 6.5 preferably about 6.5, is attained.
The leach solution with up to 90 g/L Ni and containing 5 to 10 mg/L of each of copper and iron and 10 g/L ~ S04, iS passed to cobalt separation and nickel electrowinning 18.
The nickel-copper sulphide residue is separated from the leach solution in liquid-solid separator 2G and passed to secondary stage oxidizing leach 14 under similar temperature and pressure conditions as those in the primary stage leach 12 and reacted with a controlled amount of sulphuric acid-containing nickel sulphate solution comprised of 50 g/L Ni and 50 g/L ~ S04 at a sulphuric acid to solids weight ratio in the range of 0.3:l to 0.6:1, preferably about 0.5:1. The qua~ntity o~ acid thus is controlled to provide an acid deficiency at termination of the leach represented by a pH in the range of ~.0 to 6.5, preferably about 4.5, to leach most of the r.c--in~ng nickel and to produce a leach residue of which about 60~ by weight is in a readily acid soluble form such as basic copper and nickel sulphates and ferric arsenate. The acid balance in the circuit is maintained by diverting that portion of the available nickel anolyte which is not used in the secondary oxidizing leach 14 or the non-oxidizing pressure leach 24, directly to the primary leach 12.
The leach solution containing about 70-80 g/L Ni , . ..
3 ~
and 10 g/L Cu at a pH of about 4.5 is recycled to primary stage oxidizing leach 12. The copper-rich sulphide residue comprised of copper and nickel sulphides and nickel oxide, together with the acid soluble ba~ic copper sulphate (CuSO4 2Cu(OH) 2 ~, basic nickel sulphate and ferric arsenate, is separated ~rom the leach solution by liquid-solid separator 22 and fed to an autoclave for a non-oxidizing leach 24 with a sulphuric acid containing nickel sulphate solution having about 50g~L Ni and 50 g/L ~ SO4 at an acid to solids weight ratio in the range of 0.3:1 to 0.8:1, preferably about 0.5:1 to 0.7:1. The non-oxidizing atmosphere of this leach is maintained by sparging steam or steam containing nitrogen into the autoclave to maintain the solution temperature at above 1200C, preferably in the range of 140~ to 160~C. The basic metal sulphate precipitate and the ferric arsenate are redissolved in the acid solution under the non-oxidizing conditions and the Ni, Fe and As are maintained in solution due to the pre3ence of CuZ+ from the basic copper sulphate.
The copper sulphide residue having low nickel, arsenic and iron contents is separated from the leach solution by liquid-solid separator 26 and can be fed to conventional copper smelting and refining.
The leach solution can be recycled to secondary Qtage oxldizing leach 14 or treiated in iron-arsenic precipitation step 28 in which the solution is heated to about 1500C under oxidizing conditions for precipitation of the iro~ and arsenic as ferric arsenate. The ferric arsenate precipitate is separated from the leach solution by liquid-solid separator 30 for disposal and the solution recycled to secondary oxidizing leach 14.
The process of the invention will now be described with reference to the following non-limitative examples:
EXA~PLE 1 The same nickel oxide-containing copper sulphide residue as was produced by the atmo~pheric oxidizing leach discussed above in connection with U.S. Patent No.
3,616,331, was contacted with a solution containing 50 g/L
.
: : . -~ ' l ' ' , . . ' ' ~ : ' Cu and 50g/L ~ S04 at 1500C for 120 minutes under non-oxidizing conditions. Samples of residue were taken for analysis after 60 and 120 minutes of leaching. After 60 minutes, the leach residue contained 72.4% Cu, 2.5% Ni and 22.3% S, and after 120 minutes it analyzed 75% Cu, 0.9% Ni and 21.3%S This example demonstrates that by increasing the acid concentration from less than 15 g/L ~ S0~ to 50 g/L in the leach solution, nickel oxide and nickel sulphide can be leached from the copper sulphide residue at a much lower temperature (1500C) than is required using the U.S.
Patent No. 3,616,331 process conditions (2000C). This will obviously require much less energy and the milder conditions of temperature and pressure will permit the use of less expensive materials of construction.
The same nickel oxide-containing copper sulphide residue as was produced by the atmospheric oxidizing leach discussed above in connection with U.S. Patent No.
4,323,541 was leached in a solution containing 3 g/L Cu and 33 g/L ~ S04 in a 2.SL autoclave for 180 minutes in a substantially oxygen free atmosphere. Samples of residue were taken for analy~is after 120 and 180 minutes. After 120 minutes the residue contained 73.4% Cu, 0.52~ Ni, 0.15%
Fe, 0.67% As and 21.5% S. After 180 minutes the resldue analyzed 74.3% Cu, 0.3% Ni, 0.10% Fe, 0.5% As and 21.6~ S.
The leach solution contained 10 g/L Ni, 0.5 g/L Cu and 22 g/L ~ S04 . The Cu:Ni and Cu:As ratios in the final residue were 247:1 and 149:1 respectively. The Ni:Cu ratio in the solution was 20:1.
This example demon~trates that the process of tne present invention is more effective in removing the impurity elements Ni, Fe and As than prior art oxidizing -leaches. The residue produced by the oxidizing leach disclosed in U.S. Patent No. 4,323,541 contained 9.8% Ni +
Fe + As, whereas the residue from the process of the present invention contained only 0.9~ Ni + Fe + As.
EXAMPLE 3 ~-This example illustrate~ a preferred embodiment of .
- :
~ 2 ~
the process in which a nickel-copper ~atte containing 68%
Ni, 23% Cu, 6% S, 0.9% As, 0.6% Co and 0.6% Fe was leached at 800C in the first stage of a commercial two-stage atmospheric oxidizing leach process in a solution containing 7 g/L Cu, 1.1 g/L Fe, 50 g/L Ni and 14 g/L
04 in an air spar~ed reactor. The resulting leach liquor, which formed the feed to cobalt and nickel separation and recovery circuits, containing 80 g/L Ni, 0.4 g/L Co, less than 10 mg/L each of Cu and Fe, at pH 6.5.
Approximately 40% of the nickel content of the matte was extracted into the solution. The leach residue analyzed 30~ Cu, 31% Ni, 2.4% Fe, 0.7% As and 9.4% S. Over 55~ of this residue consisted of readily acid-soluble compounds such as basic copper and nickel sulphates and ferric arsenate. The balance consisted of cuprous sulph.de, Cu2S, cuprous oxide, C~ 0, metallic nickel, nickel sulphides ImainlY Ni3 S2 ) and nickel oxide, NiO.
The residue from this first stage oxidizing leach was reacted in a second stage atmospheric oxidizing leach at 800C with a controlled amount of sulphuric acid-containing nickel sulphate solution ~50 g/L Ni ~ 50 g/L
04 ) at a sulphuric acid to s;olids weight ratio of 0.48:1, in an air sparged reactor, for one hour. The resulting leach liquor contained 75 g/L Ni and 9 g/L Cu at pH 4.6. The leach residue contained 38% Cu, 15% Ni, 1.5%
As, 3.5% Fe and 12.6% S. About 60~ of this residue consisted o~ readily acid soluble components such as basic copper and nickel sulphates and ferric arsenate. The balance consisted of cuprous sulphides, Cu2S and Cu9 S8, nickel sulphides, Ni3 S2 and NiS, and nickel oxide, NiO.
The residue from the second stage atmospheric oxidizing leach was repulped in sulphuric acid-containing nickel sulphate solution 150 g/L Ni + 50 g/L H2 S04 ) at an acid to solids weight ratio of 0.69:1, and leached in an autoclave at 1500C in non-oxidizing conditions, under steam pressure only, ~or four hours. After the initial repulping of the residue in acid solution, the solution contained 9 g/L Cu, 54 g/L Ni and 32 g/L ~ S04, while the residue .
_ g _ -~ 2 ~
analyzed 49% Cu, 21% S, 22.7% Ni, 0.8~ Fe and 0.47%As.
After the four hour pressure leach, the solution contained 5 g/L Cu, 60 g/L Ni and 34 g/L ~ S04 while the residue analyzed 75% Cu, 20% S, 0.1% Ni, 0.01% Fe and 0.23% As, and consisted essentially of digenite, Cus S5 . The c,opper to sulphur ratio in the copper sulphide was 3.75:1.
E~AMPLE 4 This example illustrates the effect of soluble copper on Ni ~ As extraction in the non-oxidizing pressure leach.
A series of four batch pressure leach tests was carried out on second stage oxidizing leach residue from a commercial circuit to illustrate the effect of different levels of dissolved copper in the leach solution on the behaviour of nickel and arsenic. Each test was condùcted at 1500C for 3 hours in a non-oxidizing leach under steam pressure only. The solids to liquid ratio in the autoclave charge was 72 g/L. The feed solids had a composition of 44.4% Cu, 17.9% Ni, 2.2~ As, and 20.4% S. The Cu to sulphur ratio in the feed solids was 2.18:1, and only 14%
of the solids and 5% of the copper were readily soluble in the acid solution. The results o~ these tests are summarized in the Table I below:
TABLE I
Feed Solution, g/L Cu 3 5 10 20 ~ S04 40 4~) 40 40 Leach Liquid, g/L As 0.48 1.06 1.68 1.65 Cu< 0.0050.01 0.8 7.5 , Leach Residue, % As 1.82 1.24 0.20 0.22 Cu60.6 67.0 71.7 73.1 Ni1.29 0.9 0.3 0.2 S 26.0 24.9 23.0 21.7 Residue Cu:S Ratio (By Weight) 2.33 2.69 3.12 3.37 2 ~ 3 ~
.
These tests show the importance of providing sufficient dissolved copper in the feed solution to the non-oxidizing leach. With solutions containing less than lO g/L Cu, the leach residue contained 1 to 2% Ni and As, whereas with lO to 20 g/L Cu in the feed solution, the residue contained 0.2 to 0.3% Ni and As. The behaviour of the arsenic and nickel is apparently determined by the copper to sulphur ratio in the copper sulphide residue produced in the pressure leach. Sufficient soluble copper must be provided in the feed solution to produce a resid~e with a Cu:S weight ratio in the range 3:1 to 4:1, while still leaving about 2 g/L Cu in the leach solution. The quantity of soluble copper required will range from 0.05 kg Cu2+/kg of feed solids for feed material with a Cu:S ratio in the range 3:1 to 4:1, to 0.20 kg Cu2+/kg of feed solids for feed material with a Cu:S ratio of 2:l.
This example illustrates a continuous operation of the non-oxidizing pressure leach. A continuous leaching test on the non-oxidizing pressure :Leach was carried out on a sample o~ two-stage leach residue from a commercial circuit, analyzing 44.4% Cu, 17.9% Ni, 2.2% As and 20.4% S, using a six compartment horizontal autoclave. Leaching was-carried out at 150~C, under steam pressure only, with a retention time of six hours, for a period of 96 hours.
Typical results are presented in the Table II below:
:, ; ,~: . :::
- - .: : :
2 ~ 3 ~
TABLE II
Solids:Solution Ratio g/L 160 105 152 Feed Solution, g/L Cu 21 14 15 ~S04 50 50 50 Leach Liquor, g/L As 4.1 3.2 3.5 .;
Cu 1.21.2< 0.001 ~ S0~ 29 31 19 Leach Residue, ~ As 0.28 0.22 0.35 Cu 73.171.1 68.6 Ni 0.570.68 2.1 S 22.922.9 23.6 Residue Cu:S Ratio (By Weight) 3.23.1 2.9 ': :
The first two columns illustrate operation under the preferred conditions with a slight excess of soluble copper. The third column illustrates operation with a deficiency of soluble copper.
The process of the present invention provides a number of important advantages. The copper concentrate from the prccess o~ the invention is low in iron and arsenic and can be fed directly to the converter stage of a copper smelting process. In contrast, the lower grade concentrates from prior art oxidizing leaches require blending with other low nickel and arsenic content concentrates. Nickel and cobalt are chemically similar to one another and, since mattes treated by the present process may ~contain cobalt, nickel sulphate produced thereby may contain not o~ly nickel but also cobalt values.
The nickel and cobalt may be recovered from the nickel sulphate as refined metals by conventional processes. In addition, copper, gold and PGMs are chemically similar to one another. Since material treated by the present process may contain either or both of gold and PGMs, copper sulphide residue product produced by the process of the invention may contain valuable gold and PGMs. Copper, gold :. . . , ~, .: '' 3 ~
.
and PGMs may be recovered from the copper sulphide by smelting and refining by conventional processes to electrolytic copper and refined gold and PGMs.
It will be understood that other embodiments and examples of the invention will be readily apparent to a person skilled in the art, the scope of the invention being defined in the appended claims.
, ,~
Fe, 0.67% As and 21.5% S. After 180 minutes the resldue analyzed 74.3% Cu, 0.3% Ni, 0.10% Fe, 0.5% As and 21.6~ S.
The leach solution contained 10 g/L Ni, 0.5 g/L Cu and 22 g/L ~ S04 . The Cu:Ni and Cu:As ratios in the final residue were 247:1 and 149:1 respectively. The Ni:Cu ratio in the solution was 20:1.
This example demon~trates that the process of tne present invention is more effective in removing the impurity elements Ni, Fe and As than prior art oxidizing -leaches. The residue produced by the oxidizing leach disclosed in U.S. Patent No. 4,323,541 contained 9.8% Ni +
Fe + As, whereas the residue from the process of the present invention contained only 0.9~ Ni + Fe + As.
EXAMPLE 3 ~-This example illustrate~ a preferred embodiment of .
- :
~ 2 ~
the process in which a nickel-copper ~atte containing 68%
Ni, 23% Cu, 6% S, 0.9% As, 0.6% Co and 0.6% Fe was leached at 800C in the first stage of a commercial two-stage atmospheric oxidizing leach process in a solution containing 7 g/L Cu, 1.1 g/L Fe, 50 g/L Ni and 14 g/L
04 in an air spar~ed reactor. The resulting leach liquor, which formed the feed to cobalt and nickel separation and recovery circuits, containing 80 g/L Ni, 0.4 g/L Co, less than 10 mg/L each of Cu and Fe, at pH 6.5.
Approximately 40% of the nickel content of the matte was extracted into the solution. The leach residue analyzed 30~ Cu, 31% Ni, 2.4% Fe, 0.7% As and 9.4% S. Over 55~ of this residue consisted of readily acid-soluble compounds such as basic copper and nickel sulphates and ferric arsenate. The balance consisted of cuprous sulph.de, Cu2S, cuprous oxide, C~ 0, metallic nickel, nickel sulphides ImainlY Ni3 S2 ) and nickel oxide, NiO.
The residue from this first stage oxidizing leach was reacted in a second stage atmospheric oxidizing leach at 800C with a controlled amount of sulphuric acid-containing nickel sulphate solution ~50 g/L Ni ~ 50 g/L
04 ) at a sulphuric acid to s;olids weight ratio of 0.48:1, in an air sparged reactor, for one hour. The resulting leach liquor contained 75 g/L Ni and 9 g/L Cu at pH 4.6. The leach residue contained 38% Cu, 15% Ni, 1.5%
As, 3.5% Fe and 12.6% S. About 60~ of this residue consisted o~ readily acid soluble components such as basic copper and nickel sulphates and ferric arsenate. The balance consisted of cuprous sulphides, Cu2S and Cu9 S8, nickel sulphides, Ni3 S2 and NiS, and nickel oxide, NiO.
The residue from the second stage atmospheric oxidizing leach was repulped in sulphuric acid-containing nickel sulphate solution 150 g/L Ni + 50 g/L H2 S04 ) at an acid to solids weight ratio of 0.69:1, and leached in an autoclave at 1500C in non-oxidizing conditions, under steam pressure only, ~or four hours. After the initial repulping of the residue in acid solution, the solution contained 9 g/L Cu, 54 g/L Ni and 32 g/L ~ S04, while the residue .
_ g _ -~ 2 ~
analyzed 49% Cu, 21% S, 22.7% Ni, 0.8~ Fe and 0.47%As.
After the four hour pressure leach, the solution contained 5 g/L Cu, 60 g/L Ni and 34 g/L ~ S04 while the residue analyzed 75% Cu, 20% S, 0.1% Ni, 0.01% Fe and 0.23% As, and consisted essentially of digenite, Cus S5 . The c,opper to sulphur ratio in the copper sulphide was 3.75:1.
E~AMPLE 4 This example illustrates the effect of soluble copper on Ni ~ As extraction in the non-oxidizing pressure leach.
A series of four batch pressure leach tests was carried out on second stage oxidizing leach residue from a commercial circuit to illustrate the effect of different levels of dissolved copper in the leach solution on the behaviour of nickel and arsenic. Each test was condùcted at 1500C for 3 hours in a non-oxidizing leach under steam pressure only. The solids to liquid ratio in the autoclave charge was 72 g/L. The feed solids had a composition of 44.4% Cu, 17.9% Ni, 2.2~ As, and 20.4% S. The Cu to sulphur ratio in the feed solids was 2.18:1, and only 14%
of the solids and 5% of the copper were readily soluble in the acid solution. The results o~ these tests are summarized in the Table I below:
TABLE I
Feed Solution, g/L Cu 3 5 10 20 ~ S04 40 4~) 40 40 Leach Liquid, g/L As 0.48 1.06 1.68 1.65 Cu< 0.0050.01 0.8 7.5 , Leach Residue, % As 1.82 1.24 0.20 0.22 Cu60.6 67.0 71.7 73.1 Ni1.29 0.9 0.3 0.2 S 26.0 24.9 23.0 21.7 Residue Cu:S Ratio (By Weight) 2.33 2.69 3.12 3.37 2 ~ 3 ~
.
These tests show the importance of providing sufficient dissolved copper in the feed solution to the non-oxidizing leach. With solutions containing less than lO g/L Cu, the leach residue contained 1 to 2% Ni and As, whereas with lO to 20 g/L Cu in the feed solution, the residue contained 0.2 to 0.3% Ni and As. The behaviour of the arsenic and nickel is apparently determined by the copper to sulphur ratio in the copper sulphide residue produced in the pressure leach. Sufficient soluble copper must be provided in the feed solution to produce a resid~e with a Cu:S weight ratio in the range 3:1 to 4:1, while still leaving about 2 g/L Cu in the leach solution. The quantity of soluble copper required will range from 0.05 kg Cu2+/kg of feed solids for feed material with a Cu:S ratio in the range 3:1 to 4:1, to 0.20 kg Cu2+/kg of feed solids for feed material with a Cu:S ratio of 2:l.
This example illustrates a continuous operation of the non-oxidizing pressure leach. A continuous leaching test on the non-oxidizing pressure :Leach was carried out on a sample o~ two-stage leach residue from a commercial circuit, analyzing 44.4% Cu, 17.9% Ni, 2.2% As and 20.4% S, using a six compartment horizontal autoclave. Leaching was-carried out at 150~C, under steam pressure only, with a retention time of six hours, for a period of 96 hours.
Typical results are presented in the Table II below:
:, ; ,~: . :::
- - .: : :
2 ~ 3 ~
TABLE II
Solids:Solution Ratio g/L 160 105 152 Feed Solution, g/L Cu 21 14 15 ~S04 50 50 50 Leach Liquor, g/L As 4.1 3.2 3.5 .;
Cu 1.21.2< 0.001 ~ S0~ 29 31 19 Leach Residue, ~ As 0.28 0.22 0.35 Cu 73.171.1 68.6 Ni 0.570.68 2.1 S 22.922.9 23.6 Residue Cu:S Ratio (By Weight) 3.23.1 2.9 ': :
The first two columns illustrate operation under the preferred conditions with a slight excess of soluble copper. The third column illustrates operation with a deficiency of soluble copper.
The process of the present invention provides a number of important advantages. The copper concentrate from the prccess o~ the invention is low in iron and arsenic and can be fed directly to the converter stage of a copper smelting process. In contrast, the lower grade concentrates from prior art oxidizing leaches require blending with other low nickel and arsenic content concentrates. Nickel and cobalt are chemically similar to one another and, since mattes treated by the present process may ~contain cobalt, nickel sulphate produced thereby may contain not o~ly nickel but also cobalt values.
The nickel and cobalt may be recovered from the nickel sulphate as refined metals by conventional processes. In addition, copper, gold and PGMs are chemically similar to one another. Since material treated by the present process may contain either or both of gold and PGMs, copper sulphide residue product produced by the process of the invention may contain valuable gold and PGMs. Copper, gold :. . . , ~, .: '' 3 ~
.
and PGMs may be recovered from the copper sulphide by smelting and refining by conventional processes to electrolytic copper and refined gold and PGMs.
It will be understood that other embodiments and examples of the invention will be readily apparent to a person skilled in the art, the scope of the invention being defined in the appended claims.
, ,~
Claims (9)
1. A process for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic which comprises:
leaching granular nickel-copper matte in an acidic solution at a temperature in the range of about 80° to 100°C under oxidizing conditions at atmospheric pressure with a deficiency of acid to produce a nickel sulphate solution and a copper-rich sulphate residue containing readily acid-soluble copper, leaching the copper-rich sulphide residue in an acidic solution under non-oxidizing conditions under elevated temperature and pressure to produce a final nickel sulphate solution containing a predetermined minimum of soluble copper and an excess of acid to maintain any iron and arsenic in solution while producing a low nickel, copper sulphide product essentially free of iron and arsenic, said product having a Cu:S weight ratio of at least 3:1.
leaching granular nickel-copper matte in an acidic solution at a temperature in the range of about 80° to 100°C under oxidizing conditions at atmospheric pressure with a deficiency of acid to produce a nickel sulphate solution and a copper-rich sulphate residue containing readily acid-soluble copper, leaching the copper-rich sulphide residue in an acidic solution under non-oxidizing conditions under elevated temperature and pressure to produce a final nickel sulphate solution containing a predetermined minimum of soluble copper and an excess of acid to maintain any iron and arsenic in solution while producing a low nickel, copper sulphide product essentially free of iron and arsenic, said product having a Cu:S weight ratio of at least 3:1.
2. A process for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic which comprises:
leaching finely divided nickel-copper matte in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure with a deficiency of acid and at a minimum temperature of about 80°C to selectively leach nickel from said matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5 and to produce a copper-rich sulphide residue containing readily acid-soluble copper;
separating the copper-rich sulphide residue from the nickel sulphate solution and leaching said residue in a closed reaction vessel at a minimum temperature of about 120°C under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of acid-soluble copper to provide a terminal concentration of at least about 2 g/L Cu2+ to produce a nickel sulphate solution containing any iron and arsenic and to produce a low nickel, copper sulphide product essentially free of said iron and arsenic.
leaching finely divided nickel-copper matte in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure with a deficiency of acid and at a minimum temperature of about 80°C to selectively leach nickel from said matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5 and to produce a copper-rich sulphide residue containing readily acid-soluble copper;
separating the copper-rich sulphide residue from the nickel sulphate solution and leaching said residue in a closed reaction vessel at a minimum temperature of about 120°C under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of acid-soluble copper to provide a terminal concentration of at least about 2 g/L Cu2+ to produce a nickel sulphate solution containing any iron and arsenic and to produce a low nickel, copper sulphide product essentially free of said iron and arsenic.
3. A process as claimed in claim 2 in which the low nickel, copper sulphide product has a Cu:S weight ratio of at least 3:1.
4. A process as claimed in claim 2 in which the low nickel, copper sulphide product has a Cu:S weight ratio in the range of 3:1 to 4:1.
5. A process as claimed in claim 1, 2, 3 or 4 in which the copper-rich sulphide residue is leached under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of sulphuric acid to provide a terminal concentration of at least about 20 g/L sulphuric acid.
6. A process as claimed in claim 2 in which the leach under oxidizing conditions is conducted with a deficiency of acid in primary and secondary oxidizing stages, wherein an excess of matte is fed to the primary oxidizing stage and wherein a controlled amount of acid is fed to the secondary stage oxidizing stage whereby at least about 5 g/L copper is hydrolyzed to basic copper sulphate.
7. A process as claimed in claim 6 in which the primary stage oxidizing leach is conducted with an excess of matte whereby essentially all copper is precipitated as copper sulphide and basic copper sulphate.
8. A process as claimed in claim 7 in which the oxidizing conditions are produced by sparging the leach solution with at least one of air and oxygen.
9. A process as claimed in claim 8 in which the copper sulphide and basic copper sulphate residue from the leach under oxidizing conditions contains by weight 10-15%
sulphur.
A process as claimed in claim 1, 2, 4, 5, 6 or 9 in which the nickel sulphate solution from the non-oxidizing leach is heated under oxidizing conditions to a temperature of about 150°C to oxidize any iron to ferric iron and any arsenic to arsenate for precipitation as ferric arsenate, and removing said ferric arsenate precipitate from the nickel sulphate solution.
sulphur.
A process as claimed in claim 1, 2, 4, 5, 6 or 9 in which the nickel sulphate solution from the non-oxidizing leach is heated under oxidizing conditions to a temperature of about 150°C to oxidize any iron to ferric iron and any arsenic to arsenate for precipitation as ferric arsenate, and removing said ferric arsenate precipitate from the nickel sulphate solution.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZW5192A ZW5192A1 (en) | 1991-10-10 | 1992-03-30 | Process for upgrading copper sulphide residue containing nickel and arsenic |
| US08/029,513 US5344479A (en) | 1992-03-13 | 1993-03-11 | Upgrading copper sulphide residues containing nickel and arsenic |
| FI931114A FI931114A (en) | 1992-03-13 | 1993-03-12 | BEHANDLING AV KOPPARSULFIDRESTER INNEHAOLLANDE NICKEL OCH ARSEN |
| ZA931770A ZA931770B (en) | 1992-03-13 | 1993-03-12 | Upgrading copper sulphide residues containing nickel and arsenic. |
| AU35166/93A AU662961B2 (en) | 1992-03-13 | 1993-03-12 | Upgrading copper sulphide residues containing nickel and arsenic |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB91.21528.5 | 1991-10-10 | ||
| GB9121528A GB9121528D0 (en) | 1991-10-10 | 1991-10-10 | Process for upgrading copper sulphide residues containing nickel and arsenic |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2063031A1 CA2063031A1 (en) | 1993-04-11 |
| CA2063031C true CA2063031C (en) | 1999-01-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2063031 Expired - Lifetime CA2063031C (en) | 1991-10-10 | 1992-03-13 | Process for upgrading copper sulphide residues containing nickel and arsenic |
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| Country | Link |
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| CA (1) | CA2063031C (en) |
| GB (1) | GB9121528D0 (en) |
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| CN111187922B (en) * | 2020-02-18 | 2022-05-06 | 云南锡业研究院有限公司 | Method for selectively leaching nickel from high-nickel copper matte under normal pressure |
| CN112626340B (en) * | 2020-12-07 | 2022-09-13 | 阳谷祥光铜业有限公司 | Treatment method of copper anode plate washing slag |
-
1991
- 1991-10-10 GB GB9121528A patent/GB9121528D0/en active Pending
-
1992
- 1992-03-13 CA CA 2063031 patent/CA2063031C/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| CA2063031A1 (en) | 1993-04-11 |
| GB9121528D0 (en) | 1991-11-27 |
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