Abstract: Mineral materials comprising copper and precious metal are subjected to an acidic leach of the copper followed by an acidic thiocyanate leach of the precious metal.

Abstract: Mineral materials comprising copper and precious metal are subjected to an acidic leach of the copper followed by an acidic thiocyanate leach of the precious metal.

Abstract: For removal of precious metal from thiocyanate leach solution, precious metal is transferred from precious metal-thiocyanate complex to precious metal-cyanide complex. Preparation of thiocyanate leach solution includes dissolving cyanide in an aqueous liquid and converting the cyanide to dissolved thiocyanate.

Abstract: A heap with precious metal-containing mineral material with precious metal locked within sulfide mineralization is subjected to bio-oxidation followed by acidic thiocyanate leaching to dissolve precious metal. Sulfide sulfur is oxidized during both of the bio-oxidation and the thiocyanate leaching.

Abstract: For removal of precious metal from thiocyanate leach solution, precious metal is transferred from precious metal-thiocyanate complex to precious metal-cyanide complex. Preparation of thiocyanate leach solution includes dissolving cyanide in an aqueous liquid and converting the cyanide to dissolved thiocyanate.

Abstract: A heap with precious metal-containing mineral material with precious metal locked within sulfide mineralization is subjected to bio-oxidation followed by acidic thiocyanate leaching to dissolve precious metal. Sulfide sulfur is oxidized during both of the bio-oxidation and the thiocyanate leaching.

Abstract: Precious metal-containing mineral material is subjected to an acidic thiocyanate leach to dissolve the precious metal as a precious metal-thiocyanate complex. A feed of the thiocyanate leach solution may include a large molar ratio of ferric iron to thiocyanate. Precious metal may be removed from pregnant thiocyanate leach solution, such as by transferring precious metal from precious metal-thiocyanate complex to precious metal-cyanide complex and then loading the precious metal-cyanide complex onto an adsorbent material. Remaining cyanide in the thiocyanate leach solution may be converted to thiocyanate for additional leaching of precious metal.

Abstract: Precious metal-containing mineral material is subjected to an acidic thiocyanate leach to dissolve the precious metal as a precious metal-thiocyanate complex. A feed of the thiocyanate leach solution may include a large molar ratio of ferric iron to thiocyanate. Precious metal may be removed from pregnant thiocyanate leach solution, such as by transferring precious metal from precious metal-thiocyanate complex to precious metal-cyanide complex and then loading the precious metal-cyanide complex onto an adsorbent material. Remaining cyanide in the thiocyanate leach solution may be converted to thiocyanate for additional leaching of precious metal.

Abstract: In one aspect, the present invention provides a method for recovering precious metal, and particularly gold, from a particulate substrate loaded with a precious metal-containing coating, in which a portion, but less than substantially all, of the particulate substrate is dissolved away to physically release precious metal-containing coating from the particulate substrate. The particulate substrate loaded with a precious metal-containing coating may be prepared during precious metal recovery operations by cementation of precious metal on a base metal particulate substrate from a pregnant leach solution, such as a leach solution including a thiosulfate lixiviant for the precious metal.

Abstract: In one aspect, the present invention provides a method for recovering precious metal, and particularly gold, from a particulate substrate loaded with a precious metal-containing coating, in which a portion, but less than substantially all, of the particulate substrate is dissolved away to physically release precious metal-containing coating from the particulate substrate. The particulate substrate loaded with a precious metal-containing coating may be prepared during precious metal recovery operations by cementation of precious metal on a base metal particulate substrate from a pregnant leach solution, such as a leach solution including a thiosulfate lixiviant for the precious metal.

Abstract: A hydrometallurgical process for the recovery of precious metal values from refractory precious metal ore materials containing preg-robbing carbon by leaching with a thiosulfate lixiviant, the process comprisinga. providing a body of particles and/or particulates of an ore material having precious metal values and preg-robbing carbonaceous components;b. contacting the body of particles and/or particulates with a thiosulfate lixiviant solution at conditions conducive to the formation of stable precious metal thiosulfate complexes;c. recovering the thiosulfate lixiviant from the body of particles and/or particulates after a period of contact which is sufficient for the lixiviant solution to become pregnant with precious metal values extracted from the ore material; andd. recovering the precious metal values from the lixiviant solution.In a preferred embodiment, the refractory ore materials are low grade precious metal ore materials.

Abstract: Refractory carbonaceous sulfide ores are treated in a manner so as to improve gold recovery by a treatment in specific combination of steps whereby the ore is treated with chlorine after pretreatment and before cyanidation; the particular steps in the treatment of the ore have been found to be necessary as the conventional pretreatment will not improve the yields on any economic basis.

Abstract: The recovery of precious metals from refractory carbonaceous and sulfidic ores or concentrates is improved by subjecting an oxidized slurry of this type of ore to thiourea leaching in the presence of carbon instead of subjecting the slurry to cyanidation leaching.

Abstract: A technique for extracting gold or silver values from an organic liquid having phosphorus or sulfur oxide groups which contains silver or gold cyanide ions by direct electrolytic deposition from the organic phase onto a cathode is disclosed.