The effect of depressant sesbania gum on the flotation of a talc-containing scheelite ore

Sodium silicate (SS) has been widely used as a depressant for the scheelite flotation. However, low selectivity and large amount of SS remains a tough problem. In this work, the effect of depressant sesbania gum (SGM) on the flotation of a talc-containing scheelite ore was investigated through pure mineral flotation and run-of-mine ore flotation tests. The flotation tests showed that the selective separation between scheelite and talc was achieved using a new reagent schedule, i.e., a lower dosage of SGM (80 mg/L) and a new collector of sulfonated oleic acid (SNaOL, 40 mol/L) at pH 9.0. A concentrate with WO3 grade of 52.0% and recovery of 78.4% was achieved by the run-of-mine ore batch flotation test. In addition, the mechanism of the selective separation was investigated by zeta-potential measurements, FTIR spectra and XPS analyses, which demonstrated that SNaOL absorbed more strongly and selectively on the "scheelite + SGM" surface than on the "talc + SGM" surface, while SGM could more selectively interact on the talc surface than on the scheelite surface. SGM absorbed on the talc surface by chemical adsorption between the Mg/Si atom of the talc surface and OH group in SGM molecule. (C) 2018 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.