Copper extraction by rapid bacteriological process

Claim 2

IN A PROCESS FOR RAPID BACTERIOLOGICAL EXTRACTION OF COPPER BY LEACHING FROM PARTICULATE MATERIALS IN PULP FORM OF A DENSITY OF FROM ABOUT 2 TO ABOUT 60% SUCH AS ORES AND CONCENTRATES CONTAINING CHALCOPYRITE IN AN AQUEOUS ACIDIC LEACHING MEDIUM CONTAINING SULFIDE OXIDIZING BACTERIAL AND A NUTRIENT FOR SAID BACETRIA AND UNDER AGITATION AND AREATION WITH AIR ENRICHED WITH CARBON DIOXIDE, THE STEP WHICH COMPRISES ADDING SILVER TO SAID LEACHING PLUP, SAID SILVER BEING IN AN AMOUNT OF AT LEAST ABOUT 200 MG/KG OF SOLID MATERIAL.

Claim 3

In a process for rapid bacteriological extraction of copper by leaching from particulate materials in pulp form of a density of from about 2% to about 60% such as ores and concentrates containing chalcopyrite in an aqueous acidic leaching medium containing sulfide oxidizing bacteria and a nutrient for said bacteria and under agitation and aeration with air enriched with carbon dioxide, the steps which comprise adding silver to said pulp, said silver being in an amount of at least about 200 mg/Kg of solid material, leaching out the copper, then removing the solid residue from the pulping medium, recovering the copper from the leaching medium, and recovering the silver from the removed solid residue.

Claim 4

In a process for rapid bacteriological extraction of copper by leaching from particulate materials in pulp form of a density of from about 2% to about 60% such as ores and concentrates containing chalcopyrite in an aqueous acidic leaching medium containing sulfide oxidizing bacteria and a nutrient for said bacteria and under agitation and aeration with air enriched with carbon dioxide, the steps which comprise adding silver to said pulp, said silver being in an amount of at least about 200 mg/Kg of solid material, leaching out the copper, then removing the solid residue from the pulping medium, recovering the copper from the leaching medium, and recovering the silver from the removed solid residue.

Claim 5

The process for rapid bacteriological extraction of copper from particulate materials containing chalcopyrite, which comprises mixing said material with a suitable aqueous acidic leaching medium containing sulfide oxidizing bacteria to make a pulp of a density of from about 2% to about 60% and containing sufficient sulfuric acid to maintain a pH of from about 1.5 to about 3.5, adding silver in finely divided or soluble form to the mixture in the range of from about 200 to 7,000 milligrams of silver per kilogram of chalcopyrite containing material, leaching out the copper, separating solids and the leaching medium, and recovering copper dissolved in the leaching medium.

Claim 6

The process for rapid bacteriological extraction of copper from particulate materials containing chalcopyrite, which comprises mixing said material with a suitable aqueous acidic leaching medium containing sulfide oxidizing bacteria to make a pulp of a density of from about 2% to about 60% and containing sufficient sulfuric acid to maintain a pH of from about 1.5 to about 3.5, adding silver in finely divided or soluble form to the mixture in the range of from about 200 to 7,000 milligrams of silver per kilogram of chalcopyrite containing material, leaching out the copper, separating solids and the leaching medium, and recovering copper dissolved in the leaching medium.

Claim 7

The process as claimed in claim 3 in which the silver is added in the form of a silver salt selected from the group consisting of silver nitrate, silver sulfate or silver chloride.

Claim 8

The process as claimed in claim 3 in which the silver is added in the form of silver sulfide or naturally occuring silver sulfides such as argentite.

Claim 9

The proCess as claimed in claim 2 in which the silver is added as soluble or insoluble salts in the range of from about 200 to about 1,000 milligrams of silver per kilogram of chalcopyrite containing material.

Claim 10

The process as claimed in claim 6 in which the silver salt is selected from the group consisting of silver nitrate, silver sulfate or silver chloride.

Claim 11

The process as claimed in claim 2 in which the silver is added as soluble or slightly soluble salts in the range of from about 500 to 750 milligrams of silver per kilogram of chalcopyrite containing material.

Claim 12

The process as claimed in claim 8 in which the silver salt is selected from the group consisting of silver nitrate, silver sulfate or silver chloride.

Claim 13

The process as claimed in claim 2 in which the silver is added as a highly insoluble salt or finely divided metal in the range of from about 700 to about 7,000 milligrams of silver per kilogram of chalcopyrite containing material.

Claim 14

The process as claimed in claim 10 in which the silver salt is silver sulfide or naturally occuring silver sulfides such as argentite.

Claim 15

The process as claimed in claim 3 including agitating the pulp to suspend the particles in the medium and simultaneously aerating the pulp with air enriched with carbon dioxide.

Claim 16

The process for rapid bacteriological extraction of copper from particulate materials containing chalcopyrite, which comprises grinding said materials to a size normally less than about 325 mesh and preferably less than about 400 mesh, mixing the ground material in an aqueous acidic leaching medium to make a pulp of a density from about 2% to about 60% and containing a sulfide-oxidizing bacteria and a nutrient for said bacteria and containing sufficient sulfuric acid to maintain a pH of about 1.5 to about 3.5, agitating the pulp, aerating the pulp with air enriched with carbon dioxide, adding silver in the form of soluble or insoluble salts or as finely divided metal in the range of from about 200 to about 7,000 mg/Kg of solid material, leaching the copper, separating the leaching medium and the solids, and recovering silver from said leaching medium and said solids.

Claim 17

The process for rapid bacteriological extraction of copper from particulate materials containing chalcopyrite, which comprises grinding said materials to a size normally less than about 325 mesh and preferably less than about 400 mesh, mixing the ground material in an aqueous acidic leaching medium to make a pulp of a density from about 2% to about 60% and containing a sulfide-oxidizing bacteria and a nutrient for said bacteria and containing sufficient sulfuric acid to maintain a pH of about 1.5 to about 3.5, agitating the pulp, aerating the pulp with air enriched with carbon dioxide, adding silver in the form of soluble or insoluble salts or as finely divided metal in the range of from about 200 to about 7,000 mg/Kg of solid material, leaching the copper, separating the leaching medium and the solids, and recovering silver from said leaching medium and said solids.