ELECTROSTATIC SEPARATION OF SULFIDES FROM QUARTZ - A POTENTIAL METHODFOR MINERAL BENEFICIATION

Artificial mixtures of galena, pyrite and sphalerite with quartz in a particulate size range of 106-150 mu m (140-100 mesh) were subjected t o electrostatic beneficiation in an alternating current force field in an inverted roof separator. Pyrite and galena, with electrical conduc tivities of similar to 1000 and similar to 100 (Omega m)(-1) respectiv ely, separated efficiently from the quartz which has a very low conduc tivity of only similar to 10(-12) (Omega m)(-1). This enabled recovery of 70% of the pyrite in only 15% of the processed mass and 40% of the galena in 11% of the processed mass. Sphalerite, with a relatively lo w conductivity of similar to 10(-5) (Omega m)(-1) was not sufficiently different from quartz to permit any beneficiation. Electrostatic sepa ration of selected sulphides from silicate gangue minerals appear to b e a technically feasible and environmentally friendly possibility.