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US 4,084,961 AGranted
Treatment of metal bearing mineral material
AssigneeSunshine Mining Company
InventorFrank Caldon
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AssigneeSunshine Mining Company
InventorFrank Caldon
Estimating the term…
Pressure leaching metal bearing mineral material such as silver and copper bearing mineral material, e.g. sulfide and/or oxide, with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under oxygen pressure, to dissolve out the corresponding desired metal values from such mineral material with nitric acid regeneration; Acid pretreatment of such metal bearing mineral material by preliminary leaching with an aqueous liquid containing sulfuric acid and very low concentration nitric acid under normal ambient pressure, to dissolve substantially attendant acid soluble metal carbonate values, e.g. manganese carbonate, from said mineral material without dissolving the desired metal values; And after treatment of the pressure leached aqueous liquid where it contains silver values as desired metal values dissolved from such mineral material, by contact with metallic copper in a closed system under autogenous steam pressure to reduce the remaining nitric acid values to gaseous form for removal from the system and to effect simultaneously by displacement both silver metal deposition or cementation from said aqueous liquid and copper metal dissolution into said aqueous liquid.
Process for recovering acid leachable metal values from metal bearing mineral material which comprises pressure leaching such metal bearing mineral material with an aqueous liquid containing about 50-260 g/l of sulfuric acid and about 0.5-5 g/l of nitric acid under oxygen pressure, to dissolve such acid leachable metal values from said mineral material into said aqueous liquid.
Process for acid pretreating metal bearing mineral material to dissolve preliminarily attendant acid soluble metal carbonate values therefrom which comprises preliminarily leaching such mineral material with an aqueous liquid containing about 30-120 g/l of sulfuric acid and about 0.05-1.5 g/l of nitric acid in an open system at ambient pressure, and recovering the leached solids from the preliminary leaching liquid.
Process for recovering silver from an acidic aqueous liquid containing dissolved silver values, sulfuric acid values and residual nitric acid values, which comprises contacting such acidic aqueous liquid with metallic copper at about 100.degree.-125.degree. C in a closed system under autogenous steam pressure of about 0-15 psig, to reduce the residual nitric acid values to gaseous form, and removing said gaseous form nitric acid values from said closed system and simultaneously effecting by displacement the deposition of the silver values as metallic silver from said aqueous liquid and the dissolution of metallic copper into said aqueous liquid.
Dependencies are inferred from the claim text.