In-situ generation of thiosulphate lixiviant systems and methods for precious metal leaching and recovery
AssigneeSeabridge Gold Inc.
InventorsMariam MELASHVILI, Theodore James SMOLIK, David DREISINGER
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Abstract
A method of extracting precious metal values from a starting material using thiosulphate as a lixiviant. The precious metal values can be recovered from solution using a reductant. The reductant may be a naturally occurring ore including as a component pyrite, chalcopyrite, marcasite and/or pyrrhotite, or can be ferrous sulphate. Sodium hydrosulphide can be added as a scavenging precipitant after the reductant to regenerate thiosulphate. The thiosulphate can be recycled to leach additional precious metal values.
Claims43
A method for recovering precious metal values from a starting material comprising the steps of:
- in a first stage:
- providing a sulphide generator;
- forming an aqueous slurry of the starting material and the sulphide generator;
- generating thiosulphate from the sulphide generator and supplying an oxidant and a basic compound to form a reaction mixture;
- and
- allowing the thiosulphate to complex the precious metal values to form a leached solution;
- and
- in a second stage:
- adding a first reductant to the leached solution to precipitate the precious metal values, wherein the first reductant comprises a copper concentrate, ferrous sulphate (FeSO4), or an iron sulphide-containing mineral.
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A method for recovering precious metal values from a sulphide-containing starting material comprising the steps of:
- in a first stage:
- forming an aqueous slurry of the sulphide-containing starting material;
- generating thiosulphate in situ from the sulphide-containing starting material by supplying an oxidant and a basic compound to form a reaction mixture;
- and
- allowing the thiosulphate to complex the precious metal values to form a leached solution;
- and
- in a second stage:
- adding a first reductant to the leached solution to precipitate the precious metal values, wherein the first reductant comprises a copper concentrate, ferrous sulphate (FeSO4), or an iron sulphide-containing mineral.
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A method of recovering precious metal values from a solution prepared using thiosulphate as a lixiviant comprising:
- adding a first reductant to the leached solution to precipitate the precious metal values, wherein the first reductant comprises a copper concentrate, ferrous sulphate (FeSO4), or an iron sulphide-containing mineral.
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Dependencies are inferred from the claim text.