The objective of this study was to investigate the feasibility of the electrostatic separation process for the beneficiation of calcium carbonate. Particle charge measurements and separation tests were conducted with samples taken from the mill air classifier circuit of an industrial scale processing plant. Separation tests with the classifier coarse fraction were done in a pilot scale free fall separator under various operating conditions. The tests work demonstrated that siliceous and coloring constituents can be selectively removed from calcium carbonate by triboelectric separation. The separation efficiency was dependent on the operating conditions such as feed material temperature, humidity and fines content. For separation of the classifier fine fraction with a particle size below 100 m a laboratory scale electrostatic separator was developed. The design consisted of an air classifier for classification and tribocharging of the feed material in combination with an electrostatic separation chamber installed in the classifier product stream. Experimental data proved that calcium carbonate and silicates can be imparted selective positive and negative surface charges when processing in the air classifier. The magnitude of the surface charge and the separation efficiency were strongly dependent on the fluid dynamic conditions in the air classifier and the separation chamber.