The flotation separation of barite-calcite using sodium silicate as depressant in the presence of sodium dodecyl sulfate

The flotation separation of barite from calcite using sodium dodecyl sulfate (SDS) as the collector and sodium silicate (SS) as the depressant has been concretely studied in this paper. The results show that SDS has high collecting ability for both barite and calcite and that the flotation separation of barite from calcite cannot be achieved by using SDS alone. The depressant sodium silicate has a selective depression effect on calcite by the control of the pulp pH at 9.0 in the presence of SDS. Through locked cycle tests, a concentrate containing 95.54% BaSO4 can be obtained from an actual ore containing 24.5% BaSO4, with a recovery of 86.11%. The zeta potential measurements, adsorption analysis and infrared spectrum studies reveal that the pre-adsorption of sodium silicate strongly favors the adsorption of SDS on the calcite surface and adversely affects SDS adsorption on the barite surface. This property is the reason for the selective depression of SS on calcite.