Process for recovering metals from solution through solvent extraction and pyrometallurgical reduction

A process for recovering copper values comprising the steps of:

• selectively extracting copper ion from an aqueous copper rich solution with an immiscible organic liquid;
• stripping copper from the organic liquid with a sufficiently strong acid containing sufficient copper for precipitating a substantially pure copper salt;
• separating the copper salt from the acid;
• dehydrating the copper salt;
• pyrometallurgically reducing the copper salt to metallic copper with a carbonaceous fuel;
• and
• recovering the anionic moiety of the copper salt for replenishing the strong acid.

A copper recovery process comprising:

• mixing substantially pure copper sulfate with a solid carbonaceous fuel for forming a permeable mass;
• igniting a portion of the carbonaceous fuel;
• introducing sufficient air for burning such fuel while maintaining a sufficiently heated reducing environment for thermally decomposing the copper sulfate and producing sulfur dioxide in a first portion of the permeable mass and for producing metallic copper in a second portion of the permeable mass;
• passing heated gases from the second portion of the permeable mass through the first portion of the permeable mass;
• and
• producing concentrated sulfuric acid from such sulfur dioxide.

A process for recovering copper comprising the steps of:

• mixing substanially pure copper sulfate a solid carbonaceous fuel for forming a permeable mass:
• burning the solid carbonaceous fuel in the permeable mass for thermally decomposing the copper sulfate and producing sulfur dioxide and for producing metallic copper, and wherein substantially all of the sulfur is removed in solid-gas reactions;
• and
• converting the sulfur dioxide to sulfuric acid.

A process for recovering copper values from an aqueous pregnant solution containing copper ion comprising the steps of:

• extracting cooper ion from the pregnant solution with an immiscible organic liquid;
• stripping copper ion from the organic liquid by contacting the organic liquid with a sulfuric acid solution having a sufficient copper concentration for precipitating substantially pure copper sulfate due to saturation of said acid solution;
• separating such precipitated copper sulfate from the sulfuric acid solution;
• thermally decomposing the copper sulfate for forming copper oxide and sulfur dioxide;
• and
• forming sulfuric acid from such sulfur dioxide.

A copper recovery process comprising the steps of:

• leaching a copper ore with solvent extraction raffinate containing sulfuric acid for producing a pregnant solution containing copper ion;
• solvent extracting copper ion from the pregnant solution with an immiscible organic liquid and replacing copper ion in such solution with hydrogen ion for producing solvent extraction raffinate for such leaching;
• stripping copper from the organic liquid with an aqueous sulfuric acid solution containing a sufficient concentration of copper for precipitating copper sulfate and replacing copper in the organic solution with hydrogen ion;
• separating such copper sulfate from the aqueous solution;
• rinsing the separated copper sulfate and recycling the rinse solution to the aqueous sulfuric acid stripping solution;
• mixing the copper sulfate with a solid carbonaceous fuel for forming a permeable mass;
• igniting such carbonaceous fuel for establishing a combustion zone in the fragmented mass;
• introducing air into the combustion zone for burning the carbonaceous fuel and producing combustion gases;
• passing such combustion gases countercurrently through the permeable mass for successively (a) thermally decomposing copper sulfate and producing copper oxide and sulfur dioxide, and (b) reducing the copper oxide to meiallic copper;
• recovering sulfur dioxide from the combustion gases and producing sulfuric acid;
• and
• replenishing the aqueous solution with such sulfuric acid.

A copper recovery process comprising the steps of:

• leaching a copper ore with solvent extraction raffinate for producing a pregnant solution containing copper ion;
• selectively extracting copper ion from the pregnant solution with an immiscible organic liquid and replacing copper ion in such solution with hydrogen ion for producing solvent extraction raffinate for such leaching;
• stripping copper from the organic liquid with aqueous sulfuric acid solution containing a sufficient concentration of copper for precipitating substantially pure copper sulfate crystals that remain at least temporarily suspended in the solution, and replacing copper in the organic solution with hydrogen ion;
• separating such copper sulfate crystals from the aqueous solution;
• burning a carbonaceous fuel for generating heat and combustion gases;
• and
• passing such combustion gases countercurrently to the copper sulfate for successively (a) thermally decomposing copper sulfate and producing copper oxide and sulfur dioxide;
• and (b) reducing the copper oxide to metallic copper wherein substantially all of the sulfur is removed in solid-gas reactions.