INFLUENCE OF QUEBRACHO AND SODIUM-SILICATE ON FLOTATION OF CELESTITE AND CALCITE WITH SODIUM OLEATE

A study has been carried out on the action of the depressants quebrach o and sodium silicate on the flotation of the mineral species celestit e and calcite, using sodium oleate as the collector and with a particl e size below 200 mesh A.S.T.M. The experiments were performed on pure minerals in a 3 L mechanical flotation cell (subaeration) equipped wit h a 1/6 CV, 1500 r.p.m. engine. The results obtained indicate that que bracho is more effective on calcite than on celestite, although at con centrations above 0.12 g/L, quebracho completely depresses both minera ls in the pH range between 7 and 10. The depressor action of Na2SiO3 o n calcite is greater on lower concentrations of sodium oleate. The sig nificance of the depressor action of sodium silicate on celestite is l ow at concentrations below 10(-3) M. Moreover, various celestite-calci te mixtures have proved to respond to flotation according to the conce ntration of the depressant, although independent of the mixture's prop ortion.