GB2154221A - Extraction process - Google Patents
Extraction process Download PDFInfo
- Publication number
- GB2154221A GB2154221A GB08403318A GB8403318A GB2154221A GB 2154221 A GB2154221 A GB 2154221A GB 08403318 A GB08403318 A GB 08403318A GB 8403318 A GB8403318 A GB 8403318A GB 2154221 A GB2154221 A GB 2154221A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gold
- process according
- hypohalite
- noble metals
- matter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000605 extraction Methods 0.000 title description 10
- 238000000034 method Methods 0.000 claims abstract description 41
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052737 gold Inorganic materials 0.000 claims abstract description 34
- 239000010931 gold Substances 0.000 claims abstract description 34
- 238000002386 leaching Methods 0.000 claims abstract description 15
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 claims abstract description 8
- 239000002184 metal Substances 0.000 claims abstract description 8
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims abstract description 6
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000002253 acid Substances 0.000 claims abstract description 5
- 150000002739 metals Chemical class 0.000 claims abstract description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000003960 organic solvent Substances 0.000 claims abstract description 3
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical group Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 8
- 238000011084 recovery Methods 0.000 claims description 8
- ZKQDCIXGCQPQNV-UHFFFAOYSA-N Calcium hypochlorite Chemical compound [Ca+2].Cl[O-].Cl[O-] ZKQDCIXGCQPQNV-UHFFFAOYSA-N 0.000 claims description 3
- 238000011065 in-situ storage Methods 0.000 claims description 3
- 239000002002 slurry Substances 0.000 claims description 3
- 150000004763 sulfides Chemical class 0.000 claims description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical group C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 239000012141 concentrate Substances 0.000 claims description 2
- 238000005868 electrolysis reaction Methods 0.000 claims description 2
- 150000004820 halides Chemical class 0.000 claims description 2
- 239000011591 potassium Substances 0.000 claims description 2
- 229910052700 potassium Inorganic materials 0.000 claims description 2
- 239000011734 sodium Substances 0.000 claims description 2
- 229910052708 sodium Inorganic materials 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 239000000243 solution Substances 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 4
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 3
- 239000005708 Sodium hypochlorite Substances 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- -1 halide ions Chemical class 0.000 description 2
- 238000002203 pretreatment Methods 0.000 description 2
- 238000012216 screening Methods 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- IZLAVFWQHMDDGK-UHFFFAOYSA-N gold(1+);cyanide Chemical compound [Au+].N#[C-] IZLAVFWQHMDDGK-UHFFFAOYSA-N 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- PYWVYCXTNDRMGF-UHFFFAOYSA-N rhodamine B Chemical compound [Cl-].C=12C=CC(=[N+](CC)CC)C=C2OC2=CC(N(CC)CC)=CC=C2C=1C1=CC=CC=C1C(O)=O PYWVYCXTNDRMGF-UHFFFAOYSA-N 0.000 description 1
- 229940043267 rhodamine b Drugs 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 235000010269 sulphur dioxide Nutrition 0.000 description 1
- 239000004291 sulphur dioxide Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/04—Obtaining noble metals by wet processes
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/22—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition
- C22B3/24—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition by adsorption on solid substances, e.g. by extraction with solid resins
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G7/00—Compounds of gold
- C01G7/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/08—Obtaining noble metals by cyaniding
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/16—Extraction of metal compounds from ores or concentrates by wet processes by leaching in organic solutions
- C22B3/1608—Leaching with acyclic or carbocyclic agents
- C22B3/1616—Leaching with acyclic or carbocyclic agents of a single type
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
- C22B3/306—Ketones or aldehydes
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
A process, for recovering gold and/or other noble metals from matter containing such metals, comprises contacting the matter with hypohalite followed by extracting of the desired metal or metals using a suitable leaching agent (e.g. acid, organic solvent, dilute alkaline cyanide or thiourea).
Description
SPECIFICATION
Extraction process
This invention relates to the recovery of gold and other noble metal values form matter containing such values, such as ores and glacial desposits and is also applicable to recovery of such values from tailings slimes and other discarded materials from various previous methods for recovery of gold, silver and other noble metals.
As the chances of finding gold and other noble metals in viable concentrations decrease, the implementation of more economically feasible processes of recovery assumes greater commercial significance.
Previous attempts have been made to recover gold from ores by leaching methods. Thus, the earliest method used for this purpose was to leach the ore with aqua regia, a highly corrosive mixture of concentrated nitric and hydrochloric acid. The use of such a chemical mix was fraught with difficulties, including serious danger to workmen, and was abandoned, as was the use of chlorine gas in a strong acid solution, which method suffered sim ilar disadvantages. Such processes have effectively been abandoned.
A later process, introduced in South Africa in about 1890 was the cyanidation process. In a typical process, finely ground slime is allowed to settle in thickening tanks, the thickened poriton is drawn off from the bottom and transferred for leaching with a large volume of dilute metallic cyanide plus lime, et. to cyanidation tanks where, after agitation by aeration, the gold-bearing solution is bled off and the gold is removed from the solution by contacting process with actived carbon. The gold adheres to the carbon which is subsequently separated from the slimes by screening.
In a more recent and improved modification of this technique, known as the "carbon-in-pulp" process, the gold present in a leach pulp adheres to activated carbon added to the pulp and the carbon and gold are subsequently separated by screening from the pulp.
Further new processes, using more environmentally acceptable leaching agents, are described in
U.K. Patent Application Nos. 8305871, 8315241 and 8328151. Thus, matter containing gold and/or other noble metals is contacted with an aqueous leaching agent comprising a source of halide ions and an oxidising agent capable of enhancing the leaching action of the halide ions. The freed metal values may be extracted by various methods, such as the use of an activated material (e.g. activated carbon or cellulose chaff), the use of a specific complexing agent (e.g. the use of Rhodamine B for gold extraction) or the use of an organic extractant (e.g. methyl isobutyl ketone).
The presently available processes do not always give good yields, especially when used with ores which are difficult to process, such as ores, ore concentrates and tailing containing metallic sulphides. Such materials are normally calcined to remove the sulphides. This is energy expensive and the sulphur dioxide effluents are environmentally unacceptable.
The present invention seeks to provide an improved process for recovering gold and other noble metals which may be used independently of, or in conjunction with, the above-described processes and which are suitable for use with recalcitrant ores which are difficult to process.
According to the present invention, we provide a process for the recovery of gold and/or other noble metals from matter contianing such metals, comprising contacting said matter with a hypohalite and subsequently extracting the gold and/or other noble metals from the resulting mixture using a suitable leaching agent.
The hypohalite is preferably hypochlorite, such as sodium, potassium and calcium hypochlorite. It may be used as an aqueous solution or slurry.
Commercially available hypohalite may be used.
Alternatively, the hypohalite may be generated in situ by electrolysing a halide. Thus, for example, sodium hypochlorite may be produced in situ by the electrolysis of brine in the presence of the ore being treated.
After hypohalite treatment, the resulting aqueous mixture may be treated with a leaching agent, such as an acid (for example hydrochloric acid). The gold or other desired metal values may be recovered by any suitable means, for example as described in the above-referenced U.K. Patent
Applications Nos. 8305871, 8315241 and 8328151.
Thus, acidic treatment of a mixture of gold bearing material and hypochlorite followed by extraction of the resultant slurry, or separated acidic liquor, with an organic solvent, such as methyl isobutyl ketone, will result in a high proportion of the gold originally present being extracted and subsequently recovered.
Alternatively, the mixture of gold bearing material and hypohalite can be subjected to leaching with dilute alkaline cyanide solutions by known methods to increase the gold extraction efficiency.
Known cyanide processes, such as the carbon-inpulp process mentioned above or the traditional carbon bed extraction of gold cyanide, may be used to recover the gold.
A further alternative method of gold recovery, useable in conjunction with hypohalite treatment, is the thiourea method developed in South Africa for leaching sulphide ores as an alternative to the use of cyanide leaching.
The following examples illustrate the invention.
Example 1
To a 100 g sample of sulphide-containing ground ore there was slowly added 300 ml of sodium hypochlorite solution with stirring. The mixture was heated to 93 to 97"C for about half an hour and then vacuum filtered. The residue was washed with 3 x 50 ml portions of distilled water. The filtrate (total volume 416 ml) was acidified, firstly using 100 ml of 10% wlw solution of hydrochloric acid and thereafter using concentrated hydrochloric acid. The total volume of concentrated hydrochloric acid used in the overall acidification was estimated to have been 50 ml. The acid was added slowly with stirring. Chlorine was evolved below pH4, The final pH was 1.7 and the resulting leach liquor was of pale orange appearance and had a total volume, when acidified, of 540 ml.
A 200 ml portion of leach liquor was extracted with methyl isobutyl ketone. A subsequent assay of the methyl isobutyl ketone gave a gold assay of 2.70 Fg ml-1. This was equivalent to an extraction of 145.8 wg of gold from a total of 270 9 gold in the original 100 g sample of ore, i.e. an extraction efficiency of 54%.
Example 2
A sample from a sulphide-containing ore tailings dump, being conventionally treated using a known carbon-in-pulp process, was given a pre-treatment at the rate of one kilogram of calcium hypochlorite per tonne of ore. The ore was then subjected to the conventional carbon-in-pulp process and the gold value in the carbon assayed. The gold extraction rate was found to be 1.8 g per tonne using hypochlorite pre-treatment whereas the previous extraction rate, not employing hypochlorite, was 0.3 g per tonne.
Claims (13)
1. A process for the recovery of gold and/or other noble metals from matter contining such metals, comprising contacting said matter with a hypohalite and subsequently extracting the gold and/or other noble metals from the resulting mixture using a suitable leaching agent.
2. A process according to claim 1 wherein the hypohalite is hypochlorite.
3. A process according to claim 2 wherein the hypohalite is selected from sodium, potassium and calcium hypochlorite.
4. A process according to any one of claims 1 to 3 wherein the matter containing gold and/or other noble metals comprises ore, ore concentrate or tailings containing metallic sulphides.
5. A process according to any one of the preceding claims wherein the hypohalite is supplied as an aqueous solution or slurry.
6. A process according to any one of claims 1 to 4 wherein the hypohalite is generated in situ by the electrolysis of a halide in the presence of the matter being treated.
7. A process according to any one of the preceding claims wherein the metal extracted is gold.
8. A process according to any one of the preceding claims wherein the leaching agent is an acid.
9. A process according to claim 8 wherein the desired gold and/or other noble metals are subsequently extracted with an organic solvent.
10. A process according to claim 7 wherein the leaching agent comprises dilute alkaline cyanide.
11. A process according to claim 7 wherein the leaching agent comprises thiourea.
12. A process for the recovery of gold substantially as described herein with reference to Exam ple 1 or 2.
13. Gold and/or other noble metals when recovered by the process of any one of the preceding claims.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08403318A GB2154221A (en) | 1984-02-08 | 1984-02-08 | Extraction process |
| CA000574696A CA1330627C (en) | 1984-02-08 | 1988-08-12 | Process for the extraction of valuable metals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08403318A GB2154221A (en) | 1984-02-08 | 1984-02-08 | Extraction process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8403318D0 GB8403318D0 (en) | 1984-03-14 |
| GB2154221A true GB2154221A (en) | 1985-09-04 |
Family
ID=10556277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08403318A Withdrawn GB2154221A (en) | 1984-02-08 | 1984-02-08 | Extraction process |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2154221A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2180829A (en) * | 1985-09-20 | 1987-04-08 | Aurotech N L | Precious metal extraction |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB227660A (en) * | 1924-02-28 | 1925-01-22 | Alexander Nathansohn | A process for the separation of lead and zinc in roasted compound ores |
| GB1088635A (en) * | 1963-07-20 | 1967-10-25 | Philip Arthur Chubb | Treatment of silica sand |
-
1984
- 1984-02-08 GB GB08403318A patent/GB2154221A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB227660A (en) * | 1924-02-28 | 1925-01-22 | Alexander Nathansohn | A process for the separation of lead and zinc in roasted compound ores |
| GB1088635A (en) * | 1963-07-20 | 1967-10-25 | Philip Arthur Chubb | Treatment of silica sand |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2180829A (en) * | 1985-09-20 | 1987-04-08 | Aurotech N L | Precious metal extraction |
| GB2180829B (en) * | 1985-09-20 | 1989-08-16 | Aurotech N L | Precious metal extraction |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8403318D0 (en) | 1984-03-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Prasad et al. | Modern trends in gold processing—overview | |
| US4738718A (en) | Method for the recovery of gold using autoclaving | |
| US4637865A (en) | Process for metal recovery and compositions useful therein | |
| JPH0530887B2 (en) | ||
| CA1257970A (en) | Process to manufacture silver chloride | |
| US4053305A (en) | Recovery of copper and silver from sulfide concentrates | |
| US5308381A (en) | Ammonia extraction of gold and silver from ores and other materials | |
| US3767760A (en) | Process for recovery of precious metals from copper containing materials | |
| US3476552A (en) | Mercury process | |
| CA2063694A1 (en) | Ammonia extraction of gold and silver from ores and other materials | |
| CA1107077A (en) | Extraction of gold and silver | |
| NZ205153A (en) | Hydrometallurgical process for recovery of gold or silver from ores | |
| US4537628A (en) | Recovery of precious metals | |
| US5939042A (en) | Tellurium extraction from copper electrorefining slimes | |
| US5807421A (en) | Hydrometallurgical extraction process | |
| US4681628A (en) | Gold Recovery processes | |
| WO1982001195A1 (en) | Recovery of silver and gold from ores and concentrates | |
| KR0145346B1 (en) | How to extract precious metals from minerals or other precious metal-containing substances using halogen salts | |
| GB2154221A (en) | Extraction process | |
| RU2062803C1 (en) | Method for processing of bismuth-containing concentrates | |
| Tran | The hydrometallurgy of gold processing | |
| EP0257548B1 (en) | Process for the recovery of silver from zinc plant calcines and neutral or low acid leach residues with thiourea | |
| US1941914A (en) | Electrochemical process for the recovery of metals from ores and other metal bearing materials | |
| Scheiner et al. | Recovery of silver and mercury from mill tailings by electrooxidation | |
| WO2001012865A1 (en) | Method of removal of impurities from gold concentrate containing sulfides |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |