The influence of particle size of raw materials on the final WO_3 grain size

摘要

Obtaining of tungstic oxide from wolframite concentrates involves the production of synthetic scheelite and/or tungstic acid as intermediate products. The present work studies the influence of different factors affecting the particle size of these compounds and also investigates the correlation between its granulometry and the final grain size of WO_3. The research included as main goals (i) the study of the effect on the synthetic scheelite grain size of the following parameters-concentration and amount of calcium chloride; concentration of tungstate solution and type of mixing and stirring, (ii) the study of the correlation between granulometric sizes of synthetic scheelite and final tungstic oxide granulometric sizes, (iii) the study of the effect of temperature, type of agitation, concentration and amount of hydrochloric acid on the recovery and particle size of tangstic oxide. Conditions to produce WO_3 powders with tailor-made micrometric grain size from 10 to 0.5 mu m are presented.