INFLUENCE OF SODIUM SILICATE ON FLOATABILITY AND CHARGE OF HEMATITE AND QUARTZ WITH SODIUM OLEATE

摘要

Due to its low cost compared with hydroxamate and sulphonate, sodium oleate is employed in direct flotation of low-grade or waste iron ore. However, depressants are being studied. This work shows the influence of the depressant sodium silicate on hematite and quartz flotation with sodium oleate as a collector. Microflotation tests were performed in Hallimond tube at pH values 7 and 9, and the zeta potentials of both minerals were determined in the absence and presence of sodium silicate. The sodium silicate was a more efficient depressant for quartz than for hematite, and a selective separation between the two minerals is possible for low reagent concentrations. The zeta potentials of both minerals were shifted to lower values due the specific adsorption of anionic species of sodium silicate onto their surfaces.