Abstract A cyclic integrated process for the production of copper metal is provided. In this process, copper ores or copper ore concentrates or, optionally, cement copper is converted to copper metal without the necessity for pyrometallurgical operations, thus entirely eliminating any air pollution problems. The source of copper values is taken into solution by leaching with a mineral acid such as sulfuric acid, converting the copper values to soluble copper salts. The pregnant liquor containing the soluble copper salts is treated with a precipitating gas such as hydrogen sulfide to precipitate the copper values as solid copper sulfide. The copper sulfide is dried and treated in a finely divided state with a reductant gas such as hydrogen, methane (either pure or contained in natural gas) or a reformed natural gas containing hydrogen and carbon monoxide. The byproduct gaseous hydrogen sulfide of the copper sulfide reduction step is recycled to precipitate more copper sulfide from the pregnant liquor. The mother liquor is treated to recover sulfuric acid which is optionally recycled to the pregnant liquor preparation step to dissolve more copper values.
soluble iron salts of said mineral acid derived from said gangue material, a solid phase including the remainder of said gangue material, and elemental sulfur; b. separating said liquid phase from said solid phase at a temperature of at least above 120* C.; c. cooling said liquid phase to a temperature below 120* C. to form a suspension of solid elemental sulfur and a pregnant liquor containing said copper and iron salts in solution therein; d. separating said solid elemental sulfur from said pregnant liquor; e. contacting said pregnant liquor with a precipitating gas selected from the class consisting of hydrogen sulfide and mixtures which include hydrogen and hydrogen sulfide, at an elevated temperature, forming a precipitation reaction mixture including
Claim 2
Dependent Claim
14 words
a liquid phase including sulfuric acid and said soluble iron salts dissolved therein, and
Claim 3
Dependent Claim
43 words
form a byproduct comprising a gas selected from the class consisting of hydrogen sulfide and a mixture which includes hydrogen sulfide and hydrogen; and i. recycling said gaseous byproduct from said copper sulfide reduction step to said pregnant liquor reduction of step e.
Claim 4
Dependent Claim
24 words
Process of claim 1 in which hydrogen gas in the pregnant liquor precipitation step e is recycled to the copper sulfide reduction step h.
Claim 5
Dependent Claim
33 words
Process of claim 1 in which the liquid phase of step e is treated to separate sulfuric acid therefrom and in which said sulfuric acid is recycled to the copper solution step a.
Claim 6
Dependent Claim
75 words
a solid phase including precipitated sulfides of the metals of the copper-arsenic group; f. separating said solid phase from said precipitation reaction Mixture; g. drying said solid phase to produce a powdered copper sulfide intermediate product; h. contacting said powdered copper sulfide intermediate product at a temperature of at least about 650* C. with a gaseous reductant selected from the class consisting of hydrogen, methane and carbon monoxide for a length of time sufficient to