Efficiency of electrostatic separation of minerals from coal as a function of size and charge distributions of coal particles

Separation of particles according to the polarity of particle charge in an electrostatic separator is discussed with respect to the particle size and electrostatic charge distributions, the geometrical configuration of the separator, the velocity pattern in the separator, and the applied electric field. Particle dynamics within the separator is discussed with respect to the limitations imposed on efficiency of the charge separation process. Experimental data are presented for different particle size and charge distributions, and the separation efficiency for different powders is calculated. When applied to the electrostatic beneficiation of coal, additional separations may be performed in series, providing better energy recovery and removal of minerals. A two-stage separation process for cleaning of Illinois 6 coal is presented.