METHOD FOR PROCESSING HARD ALLOY SCRAP CONTAINING COBALT AND TUNGSTEN Russian patent published in 1997 - IPC

FIELD: inorganic chemistry; cobalt sulfate production. SUBSTANCE: hard alloy scrap containing tungsten carbide and cobalt metal is first subjected to oxidizing roasting, next treated with 65-85%-strong sulfuric acid at temperature 120-160 C, at acid consumption rate 1-5 cu.mm per 1 g scrap, for 2-6 h, to convert cobalt to insoluble cobalt sulfate which is recovered by subsequent leaching with water and separated from tungsten trioxide. Method makes it possible to obtain environmentally safe, pure cobalt sulfate liquors, or cobalt sulfate with low content of free sulfuric acid and low-hydrated tungsten trioxide. To lower sulfuric acid consumption, oxidized hard alloy scrap is treated with recirculated sulfuric acid solution. EFFECT: improved economic aspect due to sulfuric acid recirculation; higher environmental safety. 2 cl, 1 tbl