Studies on the recovery of tungsten from a composite wolframite-scheelite concentrate

Studies on the recovery of tungsten from a multi-metal tin-tungsten ore from Kreghystan were carried out by a combination of physical beneficiation and soda ash roast-aqueous leach technique. Cassiterite, wolframite and scheelite are the main valuable minerals in this ore. However, a significant amount of wolframite occurs finely disseminated in scheelite. This composite nature of mineralisation has limited the scope of using physical separation methods in generating individual concentrates of either wolframite or scheelite with economical recovery. In view of this, a combined tungsten minerals concentrate which is free of majority of other heavy mineral - cassiterite was first obtained by physical up-gradation methods and was later subjected to tungsten extraction by soda ash roast-aqueous leach technique. The effect of process variables such as: roasting time, temperature and feed-to-alkali ratio were studied. At optimum roasting and leaching conditions, about 95% of WO3 values were extracted. (C) 2000 Elsevier Science B.V. All rights reserved.