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US3969106A
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Selective hydrometallurgical separation of lead from complex lead-zinc-copper sulfide ores or derived concentrates
Assignee: Zeo-Mag Research Ltd
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Filing: 1975-06-03
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Granted: 1976-07-13
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Expires: 1995-06-03
Abstract
Abstract A quantitative hydrometallurgical process for the selective conversion of lead sulfide (galena) to its sulfate form under ambient conditions of temperature and pressure. The process works in the presence of associated zinc - copper - iron sulfides which survive the process in a relatively unaltered condition. It is directly applicable to ores or derived concentrates of complex sulfide systems. The lead sulfate is isolated from the ore or concentrate system by a brine wash with subsequent conversion to lead chloride. A free concentration of cupric ion is maintained during the leaching stages to act as an oxidation catalyst and to inhibit the dissolution of zinc sulfide. The forward reaction in terms of lead sulfation is controlled by a chlorite-type mineral with both anion and cation exchange capacity added to, or maintained in a dilute sulfuric acid leach cycle. The evolution of hydrogen sulfide is inhibited by the reaction rate under aeration conditions in the presence of a rigidly controlled concentration of soluble iron programmed into the leach system by imposed reducing and oxidizing conditions.
Inventors
- 👤 William John Wark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:07
CPC Classifications
C; C22; C22B; C22B13/00; C22B13/04; C22B3/00; C22B3/04; C22B3/06; C22B3/08; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
341 words
A hydrometallurgical process for the selective separation of lead values from complex sulfide ores containing lead sulfide (galena) or derived concentrates thereof, which comprises the following steps, in sequence: 1. reacting said sulfide ore or concentrate in finely divided form with a dilute non-oxidizing mineral acid under reducing conditions, and adjusting the system to a pH of 0.5, thereby to extract substantially all readily soluble iron in the system from said ore or concentrate, said mineral acid being added to the system while the ore suspension is being mildly agitated, at a rate such that hydrogen sulfide evolution is substantially inhibited; 2. effecting a liquid-solids separation while maintaining said system under reducing conditions, to remove said readily soluble iron from the system; 3. repulping the solids in dilute sulfuric acid to form an aqueous suspension of said solids, and adjusting the pH of the suspension to a value of 0.5, while contacting said suspension with an oxygen-containing gas under strong conditions of agitation; 4. adding to said suspension a water-soluble copper salt in an amount sufficient to yield a free excess of approximately 0.001 gm/liter of cupric ion (Cu + + ) in terms of the aqueous ore suspension system, and intimately contacting under strong conditions of agitation said aqueous suspension of ore for a period of 8-10 hours with an oxygen-containing gas in the presence of a naturally occurring insoluble material having a cation exchange capacity of the order of 40 milliequivalents/100 gm. and an anion exchange capacity of the order of 20 milliequivalents/100 gm. whereby there is provided a controlled amount of Fe + + in the system and said amount of Fe + + in the system and said amount of Fe + + is maintained throughout said oxidation step, said lead sulfide being substantially quantitatively converted to lead sulfate; 5. effecting a second liquid-solids separation; and 6. removing the lead values of said ores, present in the solid residue resulting from said second liquid-solids separation in the form of lead sulfate, or lead complexes, from said residue.
Claim 2
Dependent Claim
341 words
A hydrometallurgical process for the selective separation of lead values from complex sulfide ores containing lead sulfide (galena) or derived concentrates thereof, which comprises the following steps, in sequence: 1. reacting said sulfide ore or concentrate in finely divided form with a dilute non-oxidizing mineral acid under reducing conditions, and adjusting the system to a pH of 0.5, thereby to extract substantially all readily soluble iron in the system from said ore or concentrate, said mineral acid being added to the system while the ore suspension is being mildly agitated, at a rate such that hydrogen sulfide evolution is substantially inhibited; 2. effecting a liquid-solids separation while maintaining said system under reducing conditions, to remove said readily soluble iron from the system; 3. repulping the solids in dilute sulfuric acid to form an aqueous suspension of said solids, and adjusting the pH of the suspension to a value of 0.5, while contacting said suspension with an oxygen-containing gas under strong conditions of agitation; 4. adding to said suspension a water-soluble copper salt in an amount sufficient to yield a free excess of approximately 0.001 gm/liter of cupric ion (Cu + + ) in terms of the aqueous ore suspension system, and intimately contacting under strong conditions of agitation said aqueous suspension of ore for a period of 8-10 hours with an oxygen-containing gas in the presence of a naturally occurring insoluble material having a cation exchange capacity of the order of 40 milliequivalents/100 gm. and an anion exchange capacity of the order of 20 milliequivalents/100 gm. whereby there is provided a controlled amount of Fe + + in the system and said amount of Fe + + in the system and said amount of Fe + + is maintained throughout said oxidation step, said lead sulfide being substantially quantitatively converted to lead sulfate; 5. effecting a second liquid-solids separation; and 6. removing the lead values of said ores, present in the solid residue resulting from said second liquid-solids separation in the form of lead sulfate, or lead complexes, from said residue.
Claim 3
Dependent Claim
18 words
A hydrometallurgical process as in claim 1 wherein said naturally occurring material having ion exchange capacity is chlorite.
Claim 4
Dependent Claim
44 words
A process as in claim 2 wherein the chlorite used in the oxidation stage as the ion exchange material is present as a constituent of the ore being treated, said ore not being subjected an any benefication before treatment in accordance with said process.
Claim 5
Dependent Claim
37 words
A process as in claim 2 wherein the chlorite used in the oxidation stage as the ion exchange material is obtained from material selected from one of the following: wall rock, shale, schist, soil and flotation tailings.
Claim 6
Dependent Claim
12 words
A process as in claim 1 wherein said oxygen-containing gas is air.
Claim 7
Dependent Claim
43 words
A process as in claim 1 wherein step (6) comprises contacting the separated solids containing the lead sulfate with an aqueous chloride solution, thereby to effect removal of the lead values from said solids in the form of a soluble lead chloride complex.
Claim 8
Dependent Claim
18 words
A process according to claim 4 wherein the aqueous chloride solution is a strong sodium chloride brine solution.
Claim 9
Dependent Claim
28 words
A process as in claim 6 wherein the contacting of separated solids with said aqueous chloride solution is effected for a period ranging from 1 to 4 hours.
Claim 10
Dependent Claim
37 words
A process as in claim 8 wherein the chloride solution is a saturated sodium chloride solution, maintained at a temperature of about 65°C., and aeration and agitation of the solids-liquid suspension are effected throughout the contacting step.
Claim 11
Dependent Claim
18 words
A process as in claim 6 wherein said aqueous chloride solution is slightly acidified with dilute sulfuric acid.
Claim 12
Dependent Claim
29 words
A process as in claim 6 wherein said aqueous chloride solution employed for removing lead values from said solids is heated to a temperature ranging from 60° - 70°C.
Claim 13
Dependent Claim
75 words
A process according to claim 6 wherein said galena-containing complex sulfide ores or derived concentrates thereof also contain silver intimately associated with the galena, and said silver is converted during the course of the process to a water-soluble silver compound; and is subsequently stripped from the brine solution by means of a unit operation in series, based upon a displacement reaction effected by contact with finely divided lead metal, with recycle of the brine solution.
Claim 14
Dependent Claim
38 words
A process according to claim 6 wherein, in addition to recovery of lead values, soluble copper is stripped from the brine by contact with lead metal and is recycled in closed circuit for further use in the process.
Claim 15
Dependent Claim
39 words
A process as in claim 1 wherein step (6) comprises converting the lead sulfate in the separated solids to a soluble complex by contacting with ammonium salts, thereby removing the lead values from said solids as a soluble complex.
Claim 16
Dependent Claim
21 words
A process as in claim 1 wherein step (6) comprises removing the lead sulfate from said separated solids by froth flotation.
Claim 17
Dependent Claim
23 words
A process as in claim 1 wherein, in step (3) and throughout oxidation step (4), the aqueous suspension of solids is continuously aerated.
Claim 18
Dependent Claim
20 words
A process as in claim 1 wherein the naturally occurring insoluble material having ion exchange capacity is a clay-type mineral.
Claim 19
Dependent Claim
19 words
A process as in claim 17 wherein said clay-type mineral is added to the ore or concentrate being treated.
Claim 20
Dependent Claim
19 words
A process as in claim 1 wherein the naturally occurring insoluble material having ion exchange capacity is a zeolite.
Claim 21
Dependent Claim
17 words
A process as in claim 1 wherein the mineral acid employed in step (1) is sulfuric acid.
Claim 22
Dependent Claim
17 words
A process as in claim 1 wherein the mineral acid employed in step (1) is hydrochloric acid.
Claim 23
Dependent Claim
24 words
A process as in claim 1 wherein the soluble copper salt is added to the suspension during the oxidation step while aerating said system.
Claim 24
Dependent Claim
29 words
A process as in claim 22 wherein sufficient of said copper salt is added to yield approximately 0.01% cupric ion in terms of the solids in the mineral suspension.
Claim 25
Dependent Claim
30 words
A process according to claim 1 wherein the ore feedstock is initially subjected to a suitable mineral dressing procedure designed to reduce the readily soluble iron content of said feedstock.
Claim 26
Dependent Claim
40 words
A process as in claim 1 wherein said naturally occurring insoluble material is treated with a soluble ferrous salt before it is used in step (4) of the process, thereby to ensure that said material contains Fe + + ions.
Claim 27
Dependent Claim
31 words
A process as in claim 1, wherein oxidation step (4) is continued until the pH of the suspension rises to approximately 1.5, at which point the second liquid-solids separation is performed.
Claim 28
Dependent Claim
21 words
A process according to claim 1 wherein the acid solution obtained from said first liquid-solids separation is recycled in closed circuit
Claim 29
Dependent Claim
52 words
A process as in claim 1 wherein following said second liquid-solids separation step, the cation exchange material employed in the oxidation stage of said process and which is a component of the residue from step (5), is isolated and recycled in closed circuit for further use in step (4) of the process.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |