AN INTEGRATED PROCESS FOR THE RECOVERY OF TUNGSTEN AND TIN FROM A COMBINED WOLFRAMITE–SCHEELITE–CASSITERITE CONCENTRATE

This article presents results of the studies on development of viable process route for quantitative recovery of tungsten and tin values occurring together in the form of a multimineral concentrate of wolframite, scheelite, and cassiterite. The investigations were carried out using a tin–tungsten multimineral ore from Kyrgyzstan (Central Asia). Tungsten minerals in this ore occur both as distinct liberated mineral phases and as composites, viz. ultrafine dissemination of wolframite in scheelite and vice versa. Cassiterite also has similar characteristics, albeit to a lesser extent, with few grains containing ex-solution intergrowth of columbite/tantalite and very fine dissemination of tungsten minerals in its lattice. The complex nature of occurrence of both tungsten and tin minerals necessitated an integrated process comprising physical beneficiation and chemical extraction. The process route that was developed gave a tungsten and tin recovery of about 80 and 90%, respectively, on treating a primary gravity preconcentrate analyzing 16.5% WO3 and 25.7% Sn.