Caustic decomposition of scheelite and scheelite-wolframite concentrates through mechanical activation

Abstract

Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelite-wolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfully used on a commercial scale in 11 tungsten plants in our country. Industrial practice has shown that a tungsten recovery higher than 98% for sheelite concentrate and 99% for scheelite-wolframite mixed concentrate is obtained, under the conditions of NaOH/WO₃ mole ratio of 3.6–4.8, 160–170 °C, and it is suitable to treat almost any sort of tungsten ore concentrates, including low grade complex concentrate, and it is more effective than the traditional soda ash digestion process.

Keywords

mechanical activation / scheelite concentrate / caustic decomposition