Research Information System
European Metallurgical Conference, EMC 2011, Germany, 1 - 04 July 2011, vol.4, pp.1137-1148, (Full Text)
Scheelite mineral is the main raw material in tungsten production. In hydrometallurgical processes, extraction of tungsten is the most important step. There are several different proposals for the leaching procedures. Each process has its own advantages and disadvantages. The aim of this study is to investigate the dissolution behaviour of calcium tungstate in oxalic acid solutions. The effects of stirring rate, particle size, oxalic acid concentration and temperature on the dissolution rate have been investigated. The quantity of tungsten dissolved in the solution was quantitatively determined using ICP-OES apparatus and fractional conversion-time diagrams were drawn. It was found that while the dissolution reaction was completed with increasing oxalic acid concentrations at low temperatures, it could not be completed with increasing oxalic acid concentrations at high temperatures due to the formation of protective layer on the surface of reactant particle.