Selective flotation of scheelite from calcite and fluorite using a collector mixture

Collector 733, a sodium soap (C12–16COONa) is widely used industrially for scheelite flotation. Low selectivity of 733 collector is always observed. In this study, a collector mixture of 733 and MES (sodium fatty acid methyl ester sulfonate) demonstrated a high selectivity for the flotation of scheelite from calcite and fluorite. An optimal mass ratio 4:1 of 733:MES was found, producing a 65.76% WO3 concentrate grade with a recovery of 66.04% from a feed material containing only 0.57% WO3. In addition, the effect of water hardness and water glass addition were studied. The results indicated that the presence of Ca2+ or Mg2+ had little effect on the adsorption of the collector mixture at the scheelite surface. Addition of water glass for depressing calcite and fluorite had no significant effect on the adsorption of the collector mixture on the scheelite surface. The advantages of this new collector mixture (733+MES) include lower cost, low dosage, high tolerance against water hardness and high selectivity, and this collector mixture has great potential for industrial application.