Selective Tribocharging of Particles for Separation

Abstract

Selective tribocharging is a suitable way for separating mineral constituents from heterogene-ous mixtures using an electrostatic field. Though contact charging mechanjsms have been studied intensively, understanding is far from clear and complete, due to the variability of material properties and to the influence of ambient conditions, which are often difficult to control. After outlining the scientific fundamentals of contact electrification, the paper illustrates and discusses some significant cases of selective charging of minerals under different experimental conditions, pointing out the effect of operational variables. Separators of practical interest are briefly described, the performance of which is assessed on the basis of beneficiation results obtained for a variety of ores and coal both on a laboratory and industrial scale.