METHOD OF HYDROMETALLURGICAL DECOMPOSITION OF PERSISTENT WOLFRAMITE CONCENTRATES Russian patent published in 1998 - IPC

FIELD: mining industry. SUBSTANCE: invention concerns two-step autoclave-soda leaching of wolframite concentrates, including chemically nonreactive ones, providing formation of refuse cakes with tungsten trioxide content as high as 0.5%. Method is based on reducing intradiffuse retardations by means of providing in slurry directed into the first step solid products' crystallization sites arising on interaction of wolframite with alkali. Advantage of process flowsheet consists in high degree of decomposition of concentrates, exceeding 99%, and also operation with water and aqueous solutions in closed circles which makes it possible to avoid diluting produced sodium tungstenate solution. EFFECT: increased decomposition degree.