Abstract
With reference to electrostatic separation, expressions are considered for computation of kinetics of particle charging in electrostatic field and corona discharge field. Particles are represented as three-axis ellipsoids, which permits to approximate the particles of various shapes. Volume conductance and dielectric permittivity, of both particles and ambient medium are taken into consideration. Total charges and free charges of particles with high and low conductance are considered. General expression permitting to define particle charge in a time-varying electric field has been derived. An example of computation is considered, when external field varies sinusoidally, and dependence of the particle charges on the external field duration and variation rate is shown.