The effective coal desulphurization may be achieved prior to combustion by electrostatic separation of pyrite grains. In this paper, the problem of the contact electrification of pyrite and coal grains is considered and the conditions for efficient liberation and separation of pyrite microcrystals from the coal matrix are discussed. The low cost electrostatic separator and the coal crusher of our own construction are briefly described. As an example, the results of the electrostatic desulphurization of five Polish steam coals are presented. An idea to apply (for ecological reasons) an electrostatic separation together with other more expensive desulphurization methods is suggested.