Recovery of nickel and copper from sulfides

Claim 2

A process as described in claim 2 wherein the electrowinning treatment produces a spent electrolyte which is recycled to form the acidic aqueous leach solution.

Claim 3

A process as described in claim 1 wherein an oxygen partial pressure of at least about 5 atms. is employed. 5 A process as described in claim 1 wherein sulfuric acid is employed in excess stoichiometric amounts of up to about 20 percent.

Claim 4

A process as described in claim 1 wherein copper is recovered from the pregnant copper sulfate solution by cementation.

Claim 5

A process as described in claim 1 wherein copper is recovered from the pregnant copper sulfate solution by alkali precipitation.

Claim 6

A process as described in claim 1 wherein copper is recovered from the pregnant copper sulfate solution by hydrogen reduction.

Claim 7

A process for recovering copper, nickel and sulfur from materials containing the same which comprises providing a starting material in the granulated, drastically quenched state and having a copper:sulfur ratio between about 3.5:1 and 10:1; slurrying the starting material in finely divided form with an acidic aqueous solution, which solution contains copper sulfate in amounts at least stoichiometrically equivalent to the nickel contained in the starting material and sufficient sulfuric acid to maintain the solution at a pH value below about 5; heating the slurry to a temperature between about 100* C. and 250* C. under pressures generated at these temperatures to leach nickel from the starting material by metathesis to thereby produce a metathesis leach solution containing nickel and a metathesis-leach residue containing substantially all the copper in the starting materials; recovering nickel from the metathesis-leach solution; slurrying the metathesis-leach residue with an acidic aqueous solution, an aqueous sulfuric acid-iron sulfate leach solution containing at least about 2 g.p.l. iron and sulfuric acid at least stoichiometrically equivalent to the copper in the metathesis-leach residue; heating the metathesis-leach-residue slurry to a temperature between about 80* C. and 150* C. under an oxygen partial pressure of at least about 2 atms. to form a pregnant copper sulfate solution and to liberate elemental sulfur; and recovering copper from the pregnant copper sulfate solution.

Claim 8

A process as described in claim 9 wherein the starting material contains cobalt and the precious metals, and the cobalt is recovered in the metathesis-leach solution containing nickel while the precious metals are recovered from the elemental sulfur.

Claim 9

A process as described in claim 9 wherein copper is recovered from the pregnant copper sulfate solution by electrowinning whereby a spent electrolyte is produced which spent electrolyte is employed in forming the slurry with the metathesis leach residue.

Claim 10

A process as described in claim 9 wherein a portion of the pregnant copper sulfate solution is employed in forming the slurry used in metathesis leach.

Claim 11

A process as described in claim 9 wherein a portion of the pregnant copper sulfate solution is recycled to the metathesis leach in sufficient quantities to satisfy the stoichiometric copper sulfate requirements.

Claim 12

A process as described in claim 9 wherein copper is recovered by electrowinning, and the resulting spent electrolyte is employed in forming the metathesis leach residue slurry.

Claim 13

A process as described in claim 9 wherein the aqueous sulfuric acid-iron sulfate leach solution contains between about 4 g.p.l. an 10 g.p.l. iron.

Claim 14

A process as described in claim 9 wherein an oxygen partial pressure between about 2 atms. and 20 atms. is employed.

Claim 15

A process as described in claim 9 wherein the metathesis-leach-residue slurry is heated to a temperature between about 80* C. and 125* C.

Claim 16

A process as described in claim 9 whereiN the metathesis-leach-residue slurry is heated to a temperature between about 100* C. and 110* C.

Claim 17

A process as described in claim 9 wherein oxygen, partial pressures of at least about 5 atms. are employed.

Claim 18

A process for recovering nickel, copper and sulfur from materials containing the same which comprises providing a starting material in the drastically quenched state and having a nickel to copper ratio greater than about 1:2 and a copper to sulfur ratio greater than about 4:1; treating the drastically quenched material with carbon monoxide partial pressures at least about 5 atms. and less than about 100 atms. at a temperature between about 50* C. and 200* C. to form substantially pure nickel carbonyl and to provide a carbonylation residue; forming a slurry of the carbonylation residue with an acidic aqueous solution, which solution contains copper sulfate in amounts at least about stoichiometrically equivalent to the nickel contained in the carbonylation residue and sulfuric acid in amounts sufficient to maintain the solution at a pH value below about 5; heating the carbonylation residue slurry to a temperature between about 100* C. and 250* C. to leach the nickel therefrom by metathesis, to thereby produce a metathesis-leach solution containing nickel and a metathesis-leach-residue containing substantially all the copper; recovering nickel from the metathesis-leach solution; forming a slurry of the metathesis-leach-residue with an aqueous sulfuric acid-iron sulfate leach solution containing at least about 2 g.p.l. iron and sulfuric acid at least stoichiometrically equivalent to the copper in the metathesis-leach-residue; heating the metathesis-leach-residue slurry to a temperature between about 80* C. and 150* C. under oxygen partial pressures of at least about 2 atms. to produce a pregnant copper sulfate solution and to liberate elemental sulfur and recovering copper from the pregnant copper sulfates.

Claim 19

A process for treating a copper-rich fraction of copper sulfide obtained from a slowly cooled nickel-copper matte to recover copper, nickel and sulfur which comprises forming a slurry of the copper-rich fraction with an acidic aqueous solution, which solution contains copper sulfate in amounts at least about stoichiometrically equivalent to the nickel contained in the copper-rich fraction and sufficient sulfuric acid to maintain the solution at a pH value below about 5; heating the copper-rich slurry to a temperature between about 100* C. and 250* C. to leach nickel from the copper-rich fraction by metathesis to thereby produce a metathesis-leach solution containing nickel and a metathesis-leach-residue containing substantially all the copper; recovering nickel from the metathesis leach solution; forming a slurry of the metathesis-leach-residue with an aqueous sulfuric acid-iron sulfate leach solution containing at least about 2 g.p.l. iron and sulfuric acid at least stoichiometrically equivalent to the copper in the metathesis-leach-residue; heating the metathesis-leach-residue slurry to a temperature between about 80* C. and 150* C. under oxygen partial pressures of at least about two atmospheres to produce a pregnant copper sulfate solution and to liberate elemental sulfur; and recovering copper from the pregnant copper sulfates.

Claim 20

A process as described in claim 21 wherein the copper-rich fraction contains cobalt and the precious metals, and cobalt is recovered from the metathesis-leach solution containing nickel while the precious metals are recovered from the elemental sulfur.