Beneficiation of a South African Wollastonite by Magnetic Separation and Flotation

摘要

Samples from an orebody containing wollastonite (approximately 69 percent), with quartz, calcite, and iron-bearing minerals as the main impurities, were investigated for possible beneficiation. This involved attempts to reduce the iron content by magnetic separation and to remove the quartz and calcite by flotation. It was found that magnetic separation successfully reduced the iron content of the ore from 1,5 percent to less than 0,3 percent after the samples had been ground to smaller than 200 micrometers. However, flotation of the wollastonite was less successful, because the surface chemistry of the three minerals involved is very similar. Hence, selectivity could not be obtained, and high grades of wollastonite were achieved at the expense of recovery. An amine-type reagent gave the best results, 60 percent of the wollastonite being recovered at a grade of 80 percent. Zeta-potential studies were conducted so that the effect of various reagents on the minerals could be established. In general, the non-selectivity of the reagents was confirmed.