CA2204424C - Process for the extraction and production of gold and platinum-group metals through cyanidation under pressure - Google Patents
Process for the extraction and production of gold and platinum-group metals through cyanidation under pressure Download PDFInfo
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- CA2204424C CA2204424C CA 2204424 CA2204424A CA2204424C CA 2204424 C CA2204424 C CA 2204424C CA 2204424 CA2204424 CA 2204424 CA 2204424 A CA2204424 A CA 2204424A CA 2204424 C CA2204424 C CA 2204424C
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Abstract
The present invention concerns the feasibility to economically exploit ores that contain gold and platinum metals, in which the recovery of platinum metals by the conventional processes is not feasible to be employed for ores that do not present occurrences of platinum metals and mineralogically associated sulfites.
The process to extract gold, silver and platinum metals from ores, concentrates and tailings according to the present invention is achieved through cyanidation under pressure, in which the material undergoes cyanidation in an autoclave with an alkaline solution (pH between 9 and 12.5), containing concentrations of cyanide between 50 and 15,000 mg/l.
The temperature and the pressure are controlled within the range of 40 to 300°C and 0.5 to 20 atm, respectively. Prior to the cyanidation under pressure, a cyanidation stage at room temperature can be conducted either followed or not by the adsorption of the extracted gold. After pressure cyanidation, the gold is recovered from the solution by adsorption/desorption, elutriation and electrolysis or cementation and the platinum metals by precipitation or by adsorption on the resin of the expended electrolyte.
The process to extract gold, silver and platinum metals from ores, concentrates and tailings according to the present invention is achieved through cyanidation under pressure, in which the material undergoes cyanidation in an autoclave with an alkaline solution (pH between 9 and 12.5), containing concentrations of cyanide between 50 and 15,000 mg/l.
The temperature and the pressure are controlled within the range of 40 to 300°C and 0.5 to 20 atm, respectively. Prior to the cyanidation under pressure, a cyanidation stage at room temperature can be conducted either followed or not by the adsorption of the extracted gold. After pressure cyanidation, the gold is recovered from the solution by adsorption/desorption, elutriation and electrolysis or cementation and the platinum metals by precipitation or by adsorption on the resin of the expended electrolyte.
Description
"PROCESS FOR THE EXTRACT ION AND PRODUCTION OF GOLD
AND PLATINUM-GROUP METALS THROUGH CYANIDATION
UNDER PRESSURE"
$ 1~ 1F1 D OF THE INVENTION
The present invention is related to a process for the extraction of gold and platinoids (platinum, palladium, ruthenium, rhodium, iridium and osmium), through cyanidation under pressure followed by adsorption, desorption, electrolysis and precipitation to produce these metals.
BACKGROUND OF THE INVENTION
Usually the process to extract gold from ores is through the conventional 1$ cyanidation followed by adsorption. The conventional cyanide treatment, which has been in practice for almost a century, basically consists of the dissolution of the gold through a solution containing sodium or potassium cyanide under normal atmospheric conditions of temperature and pressure. The solubility of gold is usually conducted in tanks or "pachucas"
with agitation and aeration of the slurry to supply the process with the necessary oxygen. For low grade ores, the cyanidation can be conducted alternatively, through percolation of the leaching solution on ore heaps.
After the conventional cyanidation has been completed, the gold is removed from the solution through adsorption on activated carbon or ion exchange resin by processes called : "Carbon-in-pulp - CIP" or "Resin in pulp -RIP".
AND PLATINUM-GROUP METALS THROUGH CYANIDATION
UNDER PRESSURE"
$ 1~ 1F1 D OF THE INVENTION
The present invention is related to a process for the extraction of gold and platinoids (platinum, palladium, ruthenium, rhodium, iridium and osmium), through cyanidation under pressure followed by adsorption, desorption, electrolysis and precipitation to produce these metals.
BACKGROUND OF THE INVENTION
Usually the process to extract gold from ores is through the conventional 1$ cyanidation followed by adsorption. The conventional cyanide treatment, which has been in practice for almost a century, basically consists of the dissolution of the gold through a solution containing sodium or potassium cyanide under normal atmospheric conditions of temperature and pressure. The solubility of gold is usually conducted in tanks or "pachucas"
with agitation and aeration of the slurry to supply the process with the necessary oxygen. For low grade ores, the cyanidation can be conducted alternatively, through percolation of the leaching solution on ore heaps.
After the conventional cyanidation has been completed, the gold is removed from the solution through adsorption on activated carbon or ion exchange resin by processes called : "Carbon-in-pulp - CIP" or "Resin in pulp -RIP".
The platinoids consist of chemical elements formed by platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), iridium (Ir) and osmium (Os), which may occur in association with the gold ore. However, its dissolution through conventional cyanidation is rather low in the range of only 20%. At the currently exploited large platinoid ore reserves, these elements occur in association with metallic sulfides and are extracted through concentration and fusion in accordance with the classic platinoid production process as described below.
In the conventional process, the ground ore undergoes a gravity concentration process on a vibration table to separate ores that are rich in platinoids. The table tailings are subjected to flotation to concentrate the sulfide minerals, which contain platinoid arsenates and sulfides and finely divided platinoids. After filtering and drying the Hotted, a concentrate is obtained which contains a small percentage of S, Cu, Ni and rc, and a platinoids yield 10 to 50-fold greater than the Notation feed stock. After transformed in pellets, the concentrate undergoes a reduction fusion in a electric furnace, in which is formed a concentrate that is called the "green matte", chiefly containing Ni, Cu and platinoids. This concentrate is then treated in a converter in which oxygen is blown in to convert the iron sulfides into iron oxides, forming the scoria and the adjustment of the sulfur content for the next stage. The resulting concentrate, the so called "white matte", contains more than 1% of platinoids. During the slow cooling process, in the "matte" phase occurs the formation of copper sulfide free from platinoids and almost iron free and a homogeneously distributed Ni-Cu-Fe phase, containing a high concentration of platinoids.
The material is then ground and immediately followed by magnetic separation where the magnetic phase of Ni-Cu-Fe rich in platinoids is recovered. The base metals are removed by sulfuric leaching. This results in a platinoid concentrate of 50 to 90'%,. 'This rich concentrate is then refined, which varies in accordance with the amount of impurities present in the concentrate.
The traditional route makes use of the solubility of Au, Pt and Pd in aqua regia and the ease to reduce gold to metal by the addition of iron salts or 502, when dissolved in aqua regia.
However, when the platinoid does not occur in association with metallic sulfides, the traditional process presents certain limitations during the flotation and concentration stage, since platinoids, which are not associated with metallic sulfides do not easily float. In these ores, the platinoid usually occurs in the form of metal :clloys, comhinc~d ~monfigt themselves freely with gold and silver or associated with oxides.
RESUME OF THE INVENTION
Therefore, an objective of the present invention is the economical feasibility to exploitation platinoids containing ores, whether or not associated with gold and silver, through an improved process, which enables the direct extraction of platinoids from the ore "in natura", concentrates or tailings, by dissolution and purification of the solution, electrolysis and precipitation.
Accor clingly, the process of the present invention comprises conventional cyanidation, CIP or FLIP (optional) adsorption, cyaniclation under pressure, and cooling in flash tanks. After obtaining solutions rich in gold, silver and platinoids, the production of the metals is achieved through the traditional adsoption and desorption processes, electro lysis or precipitation of the gold and the platinoids being recovered on the resin.
Thus, the obj ect of the invention as claimed is to provide a process for the extraction and production of gold and platinoids, through the pressure cyanidation of ore, concentrates or tailings comprising by a cyanidation stage in a reactor under pressure and temperature control, in which the pressure is maintained between 1.0 and 10 atm and the temperature between 80 and 180°C; the CN- concentration in solution varying between 50 and 15,000 mg/1, in which the pH range has been adjusted between 9 and 12,5 by the addition of alkalization agents and with a reactor residence time varying between 15 minutes and 72 hours and the concentration of solids in the slurry between 10 and 500.
l~ r-r_I111,~D__>~~9~52~ 1~-~Y~L~-r_~Q~t '.L'he process according to the present invention shall be described below in detail and in reference to Figures 1 and 2, showing two alternative routes wlmch can be employed in its execution.
4a The process according to the present invention comprises initially the cyanidation at room temperature of an ore containing slurry, concentrate or tailings, the contact with an alltaline solution of containing sodium or potassium cyanide having a CN concentration that varies between 50 and 1.5,000 mg/l. The pH of the solution is adjusted between 9 and 1.2.5 by the addition of alkalizing agents, such as lime or caustic soda. The contact of the ore carrying slurry, concentrate or tailings with the alkaline cyanide solution is performed in tanks that are equipped with agitation and/or aeration, for a period between 4 and 72 hours. The percentage of solids in the slurry varies from 10 to '70%.
Following, the slurry may enter into contact with activated carbon or ion exchange resin for the adsorption of the extracted metals, such as gold, platinoids and silver, producing loaded carbon or resin, which shall be subsequently processed. The contact with the above mentioned slurry is performed countercurrently in tanks. The addition of carbon or ion exchange resin is regulated in accordance with the dissolved metal content in solution and varying between 5 and 100 grams of carbon per liter of solution. Alternatively, the slurry can be submitted to a single liquid/solid separation, producing a solution rich in gold and platinoids, which is subsequently processed.
After the solid/liquid adsorption or separation, the slurry is then submitted to cyanidation under pressure, which consists of leaching in an alkaline solution of sodium cyanide in an autoclave. The leaching is accomplished at a pressure that varies between 0.5 and 20 atmospheres and at a temperature between 40 and 300°C.
The CN concentration in the resulting solution varies between 50 and 15,000 mg/1 and the pH is adjusted to be in the range of 9 and 12,5 by the addition of alkalizing agents, such as lime or caustic soda.
Depending on the ore's behavior, oxygen (Oz) may be added to the system, in the form of gas or peroxides. The addition of 02 varies between 0 and lkg/kg of ore. The residence time in the autoclave varies from 15 minutes to 72 hours. The percentage of the solids in the slurx,y can be between 10 and 70%.
After pressure leaching the slurry is transferred to a "flash tank", that has the purpose to stabilize the temperature and pressure conditions rates compatible with the environment. '1'he residence time in the flash tank may vary between 0.01 and 72 hours.
At the completion of the process the slurry contains tai~;r,~ with a very low gold, silver and platinoid content, which is then processed to obtain the desired metals. The foregoing process consists basically of adsorption, desorption, electrolysis or the cementing of the gold and precipitation or the adsorption of the platinoids on resin.
hollowing, as a non limiting example of the scope of the present invention is described a gold extraction test based on. the pressure cyanid.ation process.
~1'L~
Ure containing 18g/t gold (Au), 1.9 g/t platinum (Pt) and 2.2 g/t palladium (I'd) was submitted to a test to demonstrate the process of the present invention on a laboratory scale. 'rhe researched ore does not present any association with platinoid containing sulfites, in which the tailings chiefly consisted of silicates and oxides.
rust, a slurry was prepared containing 50% of solids and cyanidation was accomplished in a carboy on a roller table (conventional cyanidation), with a pH adjusted to 10.5 with the addition of lime and 500 g/1 of NaCN. The test lasted for 24 hours at room temperature. At the end of the test the slurry was filtered. The solution was analyzed for Au, Pt and Pd, and the tailings were divided into two samples. The first sample to check and analyze the contents of Au, Pt and Pd, and the second to perform the next stage of tests.
The cyanidation tailings were re-slurried to a concentration of 30% solids.
1.8 g/1 of NaCN was added to the slurry and the pH was adjusted to 10.5 by the addition of lime. The slurry was then transferred to an autoclave with agitation and its was leached for 4 hours. The test's average temperature and pressure was respectively 95° C and 1.2 atm, the maximum pressure being 3.4 atm.
The results of the tests are summarized on the following Table I.
Table I - Metallurgical recovery obtained in the pressure cvanidation test.
Metal Recovery During Recovery During Total Room Temperature Pressure Recovery Cyanidation Stage Cyanidation Stage Au 99.0% 85.0% 99.9%
Pt 11.8% 60.8% 65.4%
Pd 36.8% 69.9% 80.9%
g It can be clearly observed on Table I, that the process in accordance with the present invention demonstrated that the major benefit was the substantial increase in the recovery of the platinoid as compared to the conventional cyanidation. In the example this represents the first stage of the process of the present invention. With regards to gold, the recovery was merely complementary in the light that the room temperature cyanidation was practically able to recover all the gold in the ore in question.
In relation to the classic extraction process of the platinoid, the current invention presents itself as an excellent alternative by the substitution of flotation and pyrometallurgical stages for a simpler hydrometallurgical process with comparable metal recovery. Additionally, it consists in an important alternative for the treatment of oxidized ores, which do not present an association with platinoid sulfides.
The foregoing example is shown to elucidate with a greater degree to those skilled in the art, nevertheless not limited to the present process already mentioned above.
In the conventional process, the ground ore undergoes a gravity concentration process on a vibration table to separate ores that are rich in platinoids. The table tailings are subjected to flotation to concentrate the sulfide minerals, which contain platinoid arsenates and sulfides and finely divided platinoids. After filtering and drying the Hotted, a concentrate is obtained which contains a small percentage of S, Cu, Ni and rc, and a platinoids yield 10 to 50-fold greater than the Notation feed stock. After transformed in pellets, the concentrate undergoes a reduction fusion in a electric furnace, in which is formed a concentrate that is called the "green matte", chiefly containing Ni, Cu and platinoids. This concentrate is then treated in a converter in which oxygen is blown in to convert the iron sulfides into iron oxides, forming the scoria and the adjustment of the sulfur content for the next stage. The resulting concentrate, the so called "white matte", contains more than 1% of platinoids. During the slow cooling process, in the "matte" phase occurs the formation of copper sulfide free from platinoids and almost iron free and a homogeneously distributed Ni-Cu-Fe phase, containing a high concentration of platinoids.
The material is then ground and immediately followed by magnetic separation where the magnetic phase of Ni-Cu-Fe rich in platinoids is recovered. The base metals are removed by sulfuric leaching. This results in a platinoid concentrate of 50 to 90'%,. 'This rich concentrate is then refined, which varies in accordance with the amount of impurities present in the concentrate.
The traditional route makes use of the solubility of Au, Pt and Pd in aqua regia and the ease to reduce gold to metal by the addition of iron salts or 502, when dissolved in aqua regia.
However, when the platinoid does not occur in association with metallic sulfides, the traditional process presents certain limitations during the flotation and concentration stage, since platinoids, which are not associated with metallic sulfides do not easily float. In these ores, the platinoid usually occurs in the form of metal :clloys, comhinc~d ~monfigt themselves freely with gold and silver or associated with oxides.
RESUME OF THE INVENTION
Therefore, an objective of the present invention is the economical feasibility to exploitation platinoids containing ores, whether or not associated with gold and silver, through an improved process, which enables the direct extraction of platinoids from the ore "in natura", concentrates or tailings, by dissolution and purification of the solution, electrolysis and precipitation.
Accor clingly, the process of the present invention comprises conventional cyanidation, CIP or FLIP (optional) adsorption, cyaniclation under pressure, and cooling in flash tanks. After obtaining solutions rich in gold, silver and platinoids, the production of the metals is achieved through the traditional adsoption and desorption processes, electro lysis or precipitation of the gold and the platinoids being recovered on the resin.
Thus, the obj ect of the invention as claimed is to provide a process for the extraction and production of gold and platinoids, through the pressure cyanidation of ore, concentrates or tailings comprising by a cyanidation stage in a reactor under pressure and temperature control, in which the pressure is maintained between 1.0 and 10 atm and the temperature between 80 and 180°C; the CN- concentration in solution varying between 50 and 15,000 mg/1, in which the pH range has been adjusted between 9 and 12,5 by the addition of alkalization agents and with a reactor residence time varying between 15 minutes and 72 hours and the concentration of solids in the slurry between 10 and 500.
l~ r-r_I111,~D__>~~9~52~ 1~-~Y~L~-r_~Q~t '.L'he process according to the present invention shall be described below in detail and in reference to Figures 1 and 2, showing two alternative routes wlmch can be employed in its execution.
4a The process according to the present invention comprises initially the cyanidation at room temperature of an ore containing slurry, concentrate or tailings, the contact with an alltaline solution of containing sodium or potassium cyanide having a CN concentration that varies between 50 and 1.5,000 mg/l. The pH of the solution is adjusted between 9 and 1.2.5 by the addition of alkalizing agents, such as lime or caustic soda. The contact of the ore carrying slurry, concentrate or tailings with the alkaline cyanide solution is performed in tanks that are equipped with agitation and/or aeration, for a period between 4 and 72 hours. The percentage of solids in the slurry varies from 10 to '70%.
Following, the slurry may enter into contact with activated carbon or ion exchange resin for the adsorption of the extracted metals, such as gold, platinoids and silver, producing loaded carbon or resin, which shall be subsequently processed. The contact with the above mentioned slurry is performed countercurrently in tanks. The addition of carbon or ion exchange resin is regulated in accordance with the dissolved metal content in solution and varying between 5 and 100 grams of carbon per liter of solution. Alternatively, the slurry can be submitted to a single liquid/solid separation, producing a solution rich in gold and platinoids, which is subsequently processed.
After the solid/liquid adsorption or separation, the slurry is then submitted to cyanidation under pressure, which consists of leaching in an alkaline solution of sodium cyanide in an autoclave. The leaching is accomplished at a pressure that varies between 0.5 and 20 atmospheres and at a temperature between 40 and 300°C.
The CN concentration in the resulting solution varies between 50 and 15,000 mg/1 and the pH is adjusted to be in the range of 9 and 12,5 by the addition of alkalizing agents, such as lime or caustic soda.
Depending on the ore's behavior, oxygen (Oz) may be added to the system, in the form of gas or peroxides. The addition of 02 varies between 0 and lkg/kg of ore. The residence time in the autoclave varies from 15 minutes to 72 hours. The percentage of the solids in the slurx,y can be between 10 and 70%.
After pressure leaching the slurry is transferred to a "flash tank", that has the purpose to stabilize the temperature and pressure conditions rates compatible with the environment. '1'he residence time in the flash tank may vary between 0.01 and 72 hours.
At the completion of the process the slurry contains tai~;r,~ with a very low gold, silver and platinoid content, which is then processed to obtain the desired metals. The foregoing process consists basically of adsorption, desorption, electrolysis or the cementing of the gold and precipitation or the adsorption of the platinoids on resin.
hollowing, as a non limiting example of the scope of the present invention is described a gold extraction test based on. the pressure cyanid.ation process.
~1'L~
Ure containing 18g/t gold (Au), 1.9 g/t platinum (Pt) and 2.2 g/t palladium (I'd) was submitted to a test to demonstrate the process of the present invention on a laboratory scale. 'rhe researched ore does not present any association with platinoid containing sulfites, in which the tailings chiefly consisted of silicates and oxides.
rust, a slurry was prepared containing 50% of solids and cyanidation was accomplished in a carboy on a roller table (conventional cyanidation), with a pH adjusted to 10.5 with the addition of lime and 500 g/1 of NaCN. The test lasted for 24 hours at room temperature. At the end of the test the slurry was filtered. The solution was analyzed for Au, Pt and Pd, and the tailings were divided into two samples. The first sample to check and analyze the contents of Au, Pt and Pd, and the second to perform the next stage of tests.
The cyanidation tailings were re-slurried to a concentration of 30% solids.
1.8 g/1 of NaCN was added to the slurry and the pH was adjusted to 10.5 by the addition of lime. The slurry was then transferred to an autoclave with agitation and its was leached for 4 hours. The test's average temperature and pressure was respectively 95° C and 1.2 atm, the maximum pressure being 3.4 atm.
The results of the tests are summarized on the following Table I.
Table I - Metallurgical recovery obtained in the pressure cvanidation test.
Metal Recovery During Recovery During Total Room Temperature Pressure Recovery Cyanidation Stage Cyanidation Stage Au 99.0% 85.0% 99.9%
Pt 11.8% 60.8% 65.4%
Pd 36.8% 69.9% 80.9%
g It can be clearly observed on Table I, that the process in accordance with the present invention demonstrated that the major benefit was the substantial increase in the recovery of the platinoid as compared to the conventional cyanidation. In the example this represents the first stage of the process of the present invention. With regards to gold, the recovery was merely complementary in the light that the room temperature cyanidation was practically able to recover all the gold in the ore in question.
In relation to the classic extraction process of the platinoid, the current invention presents itself as an excellent alternative by the substitution of flotation and pyrometallurgical stages for a simpler hydrometallurgical process with comparable metal recovery. Additionally, it consists in an important alternative for the treatment of oxidized ores, which do not present an association with platinoid sulfides.
The foregoing example is shown to elucidate with a greater degree to those skilled in the art, nevertheless not limited to the present process already mentioned above.
Claims (12)
1. A process for the extraction and production of gold and platinoids, through the pressure cyanidation of ore, concentrates or tailings comprising by a cyanidation stage in a reactor under pressure and temperature control, in which the pressure is maintained between 1.0 and 10 atm and the temperature between 80 and 180°C; the CN-concentration in solution varying between 50 and 15,000 mg/l, in which the pH range has been adjusted between 9 and 12,5 by the addition of alkalization agents and with a reactor residence time varying between 15 minutes and 72 hours and the concentration of solids in the slurry between and 50%.
2. The process of claim 1, wherein that oxygen (O2) can be added to the system.
3. The process of claim 2, wherein oxygen is supplied in the form of peroxides or gas.
4. The process of claim 2 or 3, wherein said O2 addition varies between 0 and 1kg/kg of ore.
5. The process of claim 1, wherein prior to the stage of cyanidation under pressure, the material undergoes a cyanidation stage at room temperature, with a pH varying between 9 and 12.5, adjusted by the addition of an alkalizing agent, containing sodium or potassium cyanide with a CN- concentration that varies between 50 and 15,000 mg/l, in which the contact is achieved in tanks provided with agitation and/or aeration, for a variable period between 4 and 72 hours and in addition the percentage of solids in the slurry varies between 10 and 70%.
6. The process according to claim 1 or 5, wherein the alkalization is achieved through the addition of lime or caustic soda.
7. The process according to claim 5, wherein between the stages of room temperature and pressure cyanidation, a slurry adsorption stage is carried out producing gold and platinoid bearing adsorbents.
8. The process according to claim 7, wherein said adsorption is achieved through the employment of activated carbon or an ion exchange resin.
9. The process according to claim 7 or 8, wherein the employment of the activated carbon or ion exchange resin is adjusted according to the content of the dissolved metals in solution, comprised within a range between 5 and 100 grams per liter of solution.
10. The process according to claim 1, wherein after the pressure cyanidation stage the solution is placed in a flash tank, in which is achieved the stabilizing of the pressure and temperature conditions at compatible rates with the environment.
11. The process according to claim 10, wherein the time of residence in the flash tank is between 0.01 and 72 hours.
12. The process according to claim 1, wherein for the recovery of gold from the cyanided solutions are employed conventional slurry adsorption processes or column, "Carbon-in-pulp - CIP", "Resin-in-pulp-RIP", "carbon-in-column 0 CIC" or "resin-in-column-RIC" in a range of 5 to 100 grams of carbon resin per liter of solution, followed by adsorption through elutriation with a caustic soda solution at concentrations of 0.1 to 10%, and optionally contains sodium cyanide in concentrations of 0 to 10%, which is followed by electrolysis or precipitation of the gold and the platinoids being recovered on the resin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BRPI9602355-4 | 1996-05-03 | ||
| BR9602355A BR9602355A (en) | 1996-05-03 | 1996-05-03 | Process for gold and platinum extraction and production through pressure cyanidation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2204424A1 CA2204424A1 (en) | 1997-11-03 |
| CA2204424C true CA2204424C (en) | 2005-07-12 |
Family
ID=4064369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2204424 Expired - Fee Related CA2204424C (en) | 1996-05-03 | 1997-05-02 | Process for the extraction and production of gold and platinum-group metals through cyanidation under pressure |
Country Status (3)
| Country | Link |
|---|---|
| BR (1) | BR9602355A (en) |
| CA (1) | CA2204424C (en) |
| ZA (1) | ZA973238B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2160480A1 (en) * | 2007-05-18 | 2010-03-10 | CESL Limited | Process for precious metal recovery from a sulphide ore or concentrate or other feed material |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE521482C2 (en) * | 1999-11-17 | 2003-11-04 | Boliden Mineral Ab | Ways to increase the lacquer exchange of gold during cyonide treatment |
| AUPS167402A0 (en) * | 2002-04-11 | 2002-05-16 | Platinum Australia Limited | Method for extracting pgms |
-
1996
- 1996-05-03 BR BR9602355A patent/BR9602355A/en not_active IP Right Cessation
-
1997
- 1997-04-16 ZA ZA9703238A patent/ZA973238B/en unknown
- 1997-05-02 CA CA 2204424 patent/CA2204424C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2160480A1 (en) * | 2007-05-18 | 2010-03-10 | CESL Limited | Process for precious metal recovery from a sulphide ore or concentrate or other feed material |
| EP2160480A4 (en) * | 2007-05-18 | 2010-12-29 | Cesl Ltd | Process for precious metal recovery from a sulphide ore or concentrate or other feed material |
| AU2008253500B2 (en) * | 2007-05-18 | 2012-08-09 | Cesl Limited | Process for precious metal recovery from a sulphide ore or concentrate or other feed material |
| EP2540846A3 (en) * | 2007-05-18 | 2013-11-13 | CESL Limited | Process for precious metal recovery from a sulphide ore or concentrate or other feed material |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2204424A1 (en) | 1997-11-03 |
| BR9602355A (en) | 1998-09-01 |
| ZA973238B (en) | 1998-06-01 |
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| EEER | Examination request | ||
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Effective date: 20160502 |