Hydrometallurgical process for treatment of sulphur ores

Claim 2

A hydrometallurgical process for treating a sulphur- and zinc-containing ore or concentrate to recover zinc therefrom, which process comprises the following three steps: (a) leaching the ore or concentrate with an aqueous solution of cupric chloride thereby forming cuprous chloride; (b) subjecting the solution thus obtained to liquid-liquid extraction by means of an organic phase to oxtract zinc into the organic phase while concurrently oxidizing cuprous chloride to cupric chloride; and (c) recovering the zinc extracted into the organic phase.

Claim 3

A process according to claim 1, wherein said aqueous solution of cupric chloride is regenerated "in situ" by means of a regenerating agent and air at atmospheric pressure.

Claim 4

A process according to claim 2, wherein said regenerating agent is hydrochloric acid.

Claim 5

A process according to claim 2, wherein said regenerating agent is ferrous chloride, the pH of said aqueous solution of cupric chloride is from 1 to 3, and the concentration of cuprous ions in said aqueous solution of cupric chloride is greater than 1 gram per liter.

Claim 6

A process according to claim 1, wherein said aqueous solution of cupric chloride contains an agent for the solubilization of the cuprous chloride selected from the group consisting of alkali metal chlorides, alkaline-earth metal chlorides, ammonium chloride and ferrous chloride.

Claim 7

A process according to claim 1, wherein the leaching step (a) is effected at a temperature of not less than 50° C.

Claim 8

A process according to claim 1, wherein said aqueous solution of cupric chloride has redox potential of from 400 to 800 millivolts relative to the potential of a hydrogen electrode throughout the leaching step (a).

Claim 9

A process according to claim 1, wherein the organic phase used in step (b) contains an organophosphorus acid as a zinc extractant.

Claim 10

A process according to claim 8, wherein said organophosphorus acid is di-2-ethyl-hexylphosphoric acid.

Claim 11

A process according to claim 8, wherein said acid is mixed with a diluent.

Claim 12

A process according to claim 10, wherein said diluent is an oil distillation fraction the ebullition point of which is about 150° C. and the content of which exceeds 99% of aromatic hydrocarbons.

Claim 13

A process according to claim 10, wherein said diluent is an oil distillation fraction which is a mixture of about 20% of aromatic hydrocarbons and about 80% of aliphatic hydrocarbons.

Claim 14

A process according to claim 8, wherein the cuprous ions contained in said leaching solution are oxidized by means of air during the extraction step (b).

Claim 15

A process according to claim 8, wherein the recovery step (c) is effected by elution with sulphuric acid.

Claim 16

A process according to claim 14, wherein the zinc sulphate solution obtained in the recovery step (c) is subjected to electrolysis.

Claim 17

A process according to claim 1, wherein the ore or concentrate also contains lead and the process additionally includes a lead recovery stage.

Claim 18

A process according to claim 16, wherein the lead recovery stage comprises precipitating lead in the metallic state by cementation.

Claim 19

A process according to claim 17, wherein said cementation is effected by means of zinc.

Claim 20

A process according to claim 16, wherein the lead recovery stage comprises cooling the leaching solution and isolating therefrom crystals of lead chloride so formed.

Claim 21

A process according to claim 19, wherein the lead chloride is dissolved in an aqueous solution of chlorides of metals selected from the group consisting of alkali and alkaline-earth metals, and lead is precipitated in the metallic state by cementation.

Claim 22

A process according to claim 19, wherein the chloride is pulped and lead is precipitated in the metallic state by cementation.

Claim 23

A process according to claim 20, wherein said cementation is effected by means of iron powder.

Claim 24

A process according to claim 1, where the ore or concentrate also contains copper and the process additionally includes a copper recovery stage.

Claim 25

A process according to claim 23, wherein the copper recovery stage comprises liquid-liquid extraction by means of an organic phase, then recovery of copper contained in the latter by elution.

Claim 26

A process according to claim 23, wherein the copper recovery stage comprises precipitating copper by cementation.

Claim 27

A process according to claim 25, wherein the cementation is effected by means of metallic lead.

Claim 28

A process according to claim 25, wherein the cementation is effected by means of zinc.

Claim 29

A process according to claim 1, wherein the ore or concentrate also contains one or more precious metals and the process additionally includes a stage for recovery of precious metals.

Claim 30

A process according to claim 28, wherein the stage for recovery of precious metals comprises precipitating the precious metals by cementation using metallic copper.

Claim 31

A process according to claim 28, wherein the stage for recovery of precious metals comprises reducing the precious metals electrolytically.

Claim 32

A process according to claim 1, wherein the leaching step (a) is conducted by first leaching with a solution containing an amount of cupric chloride approximately equal to the stoichiometric quantity necessary to dissolve the lead present in the ore or concentrate in the form of lead dichloride, isolating the lead dichloride solution, and recovering the lead therefrom, and then leaching the ore or concentrate with a solution having a cupric chloride concentration sufficient to dissolve the remainder of the non-ferrous metals present in the ore or concentrate.

Claim 33

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the lead content being low in comparison to the copper content, in the form of their metal sulphides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) contacting a portion of the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides and cuprous chloride, with metallic copper whereby silver is precipitated by cementation and recovered; (e) contacting the aqueous solution obtained from step (d) and now free of sulphur, residue, iron, and silver, with metallic lead or zinc whereby metallic copper is precipitated by cementation and recovered; (f) contacting the aqueous solution obtained from step (e) and now free of sulphur, residue, iron, silver, and copper, with metallic zinc whereby lead is precipitated by cementation and recovered; (g) combining the aqueous solution obtained from step (f) and now free of sulphur, residue, iron, silver, copper, and lead, with the remaining portion of the aqueous solution from step (d) and subjecting the thus-combined aqueous solutions to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, thereby to obtain a zinc-free aqueous phase, containing some dissolved metal chlorides, which is recycled to step (a) and an organic phase containing the extracted zinc; and (h) recovering the zinc from the organic phase of step (g) and recycling the organic phase back to step (g).

Claim 34

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the lead content being low in comparison to the copper content, in the form of their metal sulphides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) contacting a portion of the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides and cuprous chloride, with metallic copper whereby silver is precipitated by cementation and recovered; (e) contacting the aqueous solution obtained from step (d) and now free of sulphur, residue, iron, and silver, with metallic lead or zinc whereby metallic copper is precipitated by cementation and recovered; (f) contacting the aqueous solution obtained from step (e) and now free of sulphur, residue, iron, silver, and copper, with metallic zinc whereby lead is precipitated by cementation and recovered; (g) combining the aqueous solution obtained from step (f) and now free of sulphur, residue, iron, silver, copper, and lead, with the remaining portion of the aqueous solution from step (d) and subjecting the thus-combined aqueous solutions to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, thereby to obtain a zinc-free aqueous phase, containing some dissolved metal chlorides, which is recycled to step (a) and an organic phase containing the extracted zinc; and (h) recovering the zinc from the organic phase of step (g) and recycling the organic phase back to step (g).

Claim 35

The process of claim 32 wherein the zinc is recovered in step (h) as zinc sulphate by reacting the zinc-laden organic phase with an aqueous solution of sulphuric acid to obtain an aqueous solution of zinc sulphate.

Claim 36

The process of claim 33 wherein the zinc is recovered in substantially pure form by electrolyzing the zinc sulphate obtained in claim 33 to obtain zinc in a purity exceeding 99.9%, and the regenerated aqueous sulphuric acid solution is recycled to step (h).

Claim 37

The process of claim 32 wherein the silver cementation by copper is carried out by electrochemical means.

Claim 38

The process of claim 32 wherein the zinc extraction agent is an organophosphorus compound.

Claim 39

The process of claim 32 wherein the zinc extraction agent is diluted with a diluent.

Claim 40

The process of claim 37 wherein the diluent is kerosene.

Claim 41

The process of claim 37 wherein the diluent is an oil distillation fraction the ebullition point of which is about 150° C. and the content of which exceeds 99% in aromatic hydrocarbons.

Claim 42

The process of claim 37 wherein the diluent is an oil distillation fraction which is a mixture of about 20% of aromatic hydrocarbons and about 80% of aliphatic hydrocarbons.

Claim 43

The process of claim 32 wherein the zinc extraction temperature ranges between 20° and 60° C.

Claim 44

The process of claim 32 wherein the ratio of the volume of the organic phase to the volume of the aqueous phase in the zinc extraction step (g) ranges between 0.5 and 5.

Claim 45

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the lead content being high in comparison to the copper content, in the form of their metal sulphides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is reduced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) cooling the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides including lead dichloride and cuprous chloride to crystallize the lead dichloride, separating the lead dichloride crystals, and recovering the lead therefrom; (e) contacting a portion of the resulting aqueous solution now free of sulphur, residue, iron, and lead, and containing the aforesaid soluble metal chlorides and cuprous chloride, with metallic copper whereby silver is precipitated by cementation and recovered; (f) contacting the aqueous solution obtained from step (e) and now free of sulphur, residue, iron, lead, and silver, with metallic lead or zinc whereby metallic copper is precipitated by cementation and recovered; (g) combining the aqueous solution obtained from step (f) and now free of sulphur, residue, iron, lead, silver, and copper, with the remaining portion of the aqueous solution from step (e) and subjecting the thus-combined aqueous solutions to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, thereby to obtain a zinc-free aqueous phase, containing some dissolved metal chlorides, which is recycled to step (a) and an organic phase containing the extracted zinc; and (h) recovering the zinc from the organic phase of step (g) and recycling the organic phase back to step (g).

Claim 46

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the lead content being high in comparison to the copper content, in the form of their metal sulphides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is reduced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) cooling the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides including lead dichloride and cuprous chloride to crystallize the lead dichloride, separating the lead dichloride crystals, and recovering the lead therefrom; (e) contacting a portion of the resulting aqueous solution now free of sulphur, residue, iron, and lead, and containing the aforesaid soluble metal chlorides and cuprous chloride, with metallic copper whereby silver is precipitated by cementation and recovered; (f) contacting the aqueous solution obtained from step (e) and now free of sulphur, residue, iron, lead, and silver, with metallic lead or zinc whereby metallic copper is precipitated by cementation and recovered; (g) combining the aqueous solution obtained from step (f) and now free of sulphur, residue, iron, lead, silver, and copper, with the remaining portion of the aqueous solution from step (e) and subjecting the thus-combined aqueous solutions to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, thereby to obtain a zinc-free aqueous phase, containing some dissolved metal chlorides, which is recycled to step (a) and an organic phase containing the extracted zinc; and (h) recovering the zinc from the organic phase of step (g) and recycling the organic phase back to step (g).

Claim 47

The process of claim 43 wherein the lead is recovered in step (d) by redissolving the lead dichloride crystals in a member selected from the group consisting of an alkali metal chloride and an alkaline earth metal chloride and contacting the resulting solution with zinc to precipitate the lead by cementation, the resulting mother liquor being recycled to step (a).

Claim 48

The process of claim 43 wherein the lead is recovered in step (d) by pulping the lead chloride and contacting it with metallic iron or zinc to precipitate the lead by cementation, the resulting mother liquor being recycled to step (c) if ferrous chloride is involved or to step (d) if zinc chloride is involved.

Claim 49

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the copper, lead, and zinc contents being high in comparison to the other metals, in the form of their metal sulfides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) cooling the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides including lead chloride and cuprous chloride to crystallize the lead dichloride, separating the lead chloride crystals, and recovering the lead therefrom; (e) subjecting a portion of the resulting aqueous solution, now free of sulphur, residue, and lead, and containing the aforesaid soluble metal chlorides and cuprous chloride to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, whereupon an organic phase containing the extracted zinc and an aqueous phase containing the remaining soluble metal chlorides are obtained; (f) recovering the zinc from the organic phase of step (e) and recycling the organic phase back to step (e); (g) contacting the aqueous phase from step (e), now free of sulphur, residue, iron, lead, and zinc, and containing the remaining soluble metal chlorides, with copper whereby silver is precipitated by cementation and recovered; (h) subjecting the resulting aqueous solution, now free of sulphur, residue, iron, lead, zinc, and silver, and containing cuprous chloride, to liquid-liquid extraction with an organic phase containing an extraction agent for copper to obtain a copper-laden organic phase, while concurrently oxidizing the cuprous chloride to cuprous chloride which is recycled to step (a) for additional leaching; and (i) recovering the copper from the organic phase and recycling the copper-free organic phase back to step (h).

Claim 50

A hydrometallurgical process for treating an initial product selected from the group consisting of a sulphurized ore and concentrate containing, as constituents, iron, zinc, silver, copper, and lead, the copper, lead, and zinc contents being high in comparison to the other metals, in the form of their metal sulfides, to recover any or all of said constituents, comprising: (a) leaching the initial product with an aqueous solution of cupric chloride whereby the metal sulphides are converted to their corresponding soluble metal chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (a), and the iron is precipitated as goethite and separated from the aqueous solution; (d) cooling the resulting aqueous solution, now free of sulphur, residue, and iron, and containing the aforesaid soluble metal chlorides including lead chloride and cuprous chloride to crystallize the lead dichloride, separating the lead chloride crystals, and recovering the lead therefrom; (e) subjecting a portion of the resulting aqueous solution, now free of sulphur, residue, and lead, and containing the aforesaid soluble metal chlorides and cuprous chloride to liquid-liquid extraction with an organic phase containing an extraction agent for zinc, at a pH between 0.3 and 1.5, while concurrently oxidizing the cuprous chloride to cupric chloride, whereupon an organic phase containing the extracted zinc and an aqueous phase containing the remaining soluble metal chlorides are obtained; (f) recovering the zinc from the organic phase of step (e) and recycling the organic phase back to step (e); (g) contacting the aqueous phase from step (e), now free of sulphur, residue, iron, lead, and zinc, and containing the remaining soluble metal chlorides, with copper whereby silver is precipitated by cementation and recovered; (h) subjecting the resulting aqueous solution, now free of sulphur, residue, iron, lead, zinc, and silver, and containing cuprous chloride, to liquid-liquid extraction with an organic phase containing an extraction agent for copper to obtain a copper-laden organic phase, while concurrently oxidizing the cuprous chloride to cuprous chloride which is recycled to step (a) for additional leaching; and (i) recovering the copper from the organic phase and recycling the copper-free organic phase back to step (h).

Claim 51

The process of claim 46 wherein the recovery of the copper in step (g) is carried out by contacting the organic phase containing the copper with an aqueous sulphuric acid solution to obtain an aqueous solution of copper sulphate in which form the copper is recovered.

Claim 52

A hydrometallurgical process for treating a sulphurized ore or concentrate containing iron and rich in zinc and copper, in the form of their sulphides to recover the sulphur, iron, zinc, and copper values therefrom, comprising: (a) leaching the ore or concentrate with an aqueous solution of cupric chloride whereupon the zinc and copper sulphides are converted to soluble zinc and cupric chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution, in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride to oxidize the cuprous chloride to cupric chloride so as to provide a concentration of cuprous ions exceeding 1 gram per liter in the resulting aqueous solution of cupric chloride which is recycled for additional leaching to step (a) and the iron is precipitated as goethite and separated from the aqueous solution; (d) subjecting the resulting aqueous solution, now free of sulphur, residue, and iron, and containing zinc and copper chlorides to liquid-liquid extraction with a neutral organic zinc extracting agent to obtain an organic phase containing the extracted zinc and an aqueous phase containing copper chlorides; (e) recovering the zinc from the organic phase and recycling the zinc-free organic phase to step (d); (f) subjecting the aqueous phase containing copper chlorides to liquid-liquid extraction with an organic copper-extraction cationic agent to obtain an organic phase containing the copper, the acidity released by this extraction being absorbed by the regeneration of cupric chloride; and (g) recovering the copper from the organic phase and recycling the copper-free organic phase to step (f).

Claim 53

A hydrometallurgical process for treating a sulphurized ore or concentrate containing iron and rich in zinc and copper, in the form of their sulphides to recover the sulphur, iron, zinc, and copper values therefrom, comprising: (a) leaching the ore or concentrate with an aqueous solution of cupric chloride whereupon the zinc and copper sulphides are converted to soluble zinc and cupric chlorides, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (b) separating the sulphur and any unreacted residue from the reaction mixture; (c) regenerating the resulting solution, in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride to oxidize the cuprous chloride to cupric chloride so as to provide a concentration of cuprous ions exceeding 1 gram per liter in the resulting aqueous solution of cupric chloride which is recycled for additional leaching to step (a) and the iron is precipitated as goethite and separated from the aqueous solution; (d) subjecting the resulting aqueous solution, now free of sulphur, residue, and iron, and containing zinc and copper chlorides to liquid-liquid extraction with a neutral organic zinc extracting agent to obtain an organic phase containing the extracted zinc and an aqueous phase containing copper chlorides; (e) recovering the zinc from the organic phase and recycling the zinc-free organic phase to step (d); (f) subjecting the aqueous phase containing copper chlorides to liquid-liquid extraction with an organic copper-extraction cationic agent to obtain an organic phase containing the copper, the acidity released by this extraction being absorbed by the regeneration of cupric chloride; and (g) recovering the copper from the organic phase and recycling the copper-free organic phase to step (f).

Claim 54

The process of claim 48 wherein the zinc extracting agent is tributyl phosphate.

Claim 55

The process of claim 48 wherein the copper-extraction cationic agent is a compound of the formula: ##STR6##

Claim 56

A hydrometallurgical process for treating a sulphurized ore or concentrate containing iron, lead, and zinc sulphides to recover the lead and zinc values therefrom, comprising: (a) contacting the ore or concentrate with an aqueous solution of cupric chloride approximately equal to the stoichiometrical quantity necessary to dissolve only the lead contained in the ore or concentrate thereby to obtain an aqueous solution of lead chloride and a solid residue of ore or concentrate; (b) separating the aqueous solution of the lead chloride from the residue of the ore or concentrate; (c) recovering the lead from the separated aqueous solution of lead chloride; (d) leaching the residue of the ore or concentrate with an aqueous solution of cupric chloride whereupon the zinc sulphide is converted to zinc chloride, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (e) separating the sulphur and any unreacted residue from the reaction mixture; (f) regenerating the resulting solution, in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (d) and the iron is precipitated as goethite and separated from the aqueous solution; (g) subjecting the resulting aqueous solution, now free of lead, sulphur, residue, and iron, and containing zinc and copper chlorides to liquid-liquid extraction with a cationic zinc-extracing agent to obtain an organic phase containing the extracted zinc, and an aqueous phase containing copper chlorides which is recycled to step (d), the acidity released by extraction being absorbed by the regeneration of cupric chloride; and (h) recovering the zinc from the organic phase and recycling the zinc-free organic phase to step (g).

Claim 57

A hydrometallurgical process for treating a sulphurized ore or concentrate containing iron, lead, and zinc sulphides to recover the lead and zinc values therefrom, comprising: (a) contacting the ore or concentrate with an aqueous solution of cupric chloride approximately equal to the stoichiometrical quantity necessary to dissolve only the lead contained in the ore or concentrate thereby to obtain an aqueous solution of lead chloride and a solid residue of ore or concentrate; (b) separating the aqueous solution of the lead chloride from the residue of the ore or concentrate; (c) recovering the lead from the separated aqueous solution of lead chloride; (d) leaching the residue of the ore or concentrate with an aqueous solution of cupric chloride whereupon the zinc sulphide is converted to zinc chloride, the cupric chloride is reduced to cuprous chloride, and elemental sulphur is produced; (e) separating the sulphur and any unreacted residue from the reaction mixture; (f) regenerating the resulting solution, in situ, at atmospheric pressure, with air and a regenerating agent selected from the group consisting of hydrochloric acid and ferrous chloride, whereupon the cuprous chloride is oxidized to cupric chloride and recycled for additional leaching to step (d) and the iron is precipitated as goethite and separated from the aqueous solution; (g) subjecting the resulting aqueous solution, now free of lead, sulphur, residue, and iron, and containing zinc and copper chlorides to liquid-liquid extraction with a cationic zinc-extracing agent to obtain an organic phase containing the extracted zinc, and an aqueous phase containing copper chlorides which is recycled to step (d), the acidity released by extraction being absorbed by the regeneration of cupric chloride; and (h) recovering the zinc from the organic phase and recycling the zinc-free organic phase to step (g).

Claim 58

The process of claim 51 wherein the cationic zinc-extracting agent is an acid organophosphate compound.

Claim 59

The process of claim 52 wherein the acid organophosphate compound is di-2-ethyl-hexylphosphoric acid.

Claim 60

A hydrometallurgical process for treating a sulphur- and zinc-containing ore or concentrate to recover zinc therefrom, which process comprises the following three steps: (a) leaching the ore or concentrate with an aqueous solution of cupric chloride to obtain a solution containing zinc and copper in the form of cuprous ions; (b) contacting the solution thus obtained with a neutral organophosphorus compound to selectively extract zinc from the solution; and (c) recovering the zinc extracted into the neutral organophosphorus compound.

Claim 61

A hydrometallurgical process for treating a sulphur- and zinc-containing ore or concentrate to recover zinc therefrom, which process comprises the following three steps: (a) leaching the ore or concentrate with an aqueous solution of cupric chloride to obtain a solution containing zinc and copper in the form of cuprous ions; (b) contacting the solution thus obtained with a neutral organophosphorus compound to selectively extract zinc from the solution; and (c) recovering the zinc extracted into the neutral organophosphorus compound.

Claim 62

The process of claim 54, in which the zinc is recovered from the organophosphorus compound by contacting the organophosphorus compound with a stripping solution.

Claim 63

The process of claim 55, in which the stripping solution is water.

Claim 64

The process of claim 56, in which the stripping solution obtained is electrolyzed to obtain metallic zinc and chlorine.

Claim 65

The process of claim 57, in which the stripping solution obtained after being electrolyzed is recycled to step (a).

Claim 66

The process of claim 57, in which the chlorine is recycled to regenerate the leaching solution.

Claim 67

A process for extracting zinc from an aqueous solution containing zinc and copper in which at least a portion of the copper is present as cuprous ions comprising contacting the aqueous solution with an organic phase containing a cationic extraction agent having an affinity for zinc while concurrently oxidizing the cuprous ions in the aqueous solution to cupric ions.

Claim 68

A process for extracting zinc from an aqueous solution containing zinc and copper in which at least a portion of the copper is present as cuprous ions comprising contacting the aqueous solution with an organic phase containing a cationic extraction agent having an affinity for zinc while concurrently oxidizing the cuprous ions in the aqueous solution to cupric ions.

Claim 69

The process of claim 60, in which the cationic extraction agent is an acid organophosphate compound.

Claim 70

The process of claim 60, in which the cationic organic extractant is di-2-ethyl-hexylphosphoric acid.

Claim 71

The process of claim 60, in which the cationic extraction agent has an affinity for copper and copper is co-extracted with the zinc.

Claim 72

The process of claim 63, in which the cationic extraction agent is contacted with a first stripping solution to strip copper from the extraction agent.

Claim 73

The process of claim 64, in which the cationic extraction agent is contacted with a second stripping solution to strip zinc from the extraction agent.

Claim 74

The process of claim 65, in which the second stripping solution is concentrated sulphuric acid.

Claim 75

The process of claim 60, in which the aqueous solution contains ferric ions which are removed from the aqueous solution prior to contacting the aqueous solution with the cationic extraction agent.

Claim 76

The process of claim 67, in which the ferric ions are precipitated as goethite prior to contacting the aqueous solution with the cationic extraction agent.

Claim 77

The process of claim 60, in which the cuprous ions are oxidized to cupric ions with air.