Due to high demands on the quality of the products, dry beneficiation of fine and finest fillers presents great challenges to both producers and suppliers. The trend continues unabated towards steadily finer, cleaner and more homogeneous products while at the same time there is little or no selectivity of the mineral phases involved. Besides the energy-intensive grinding processes, the greatest challenge is the purity demanded in the final product which is achieved by separation of colouring and abrading mineral parts. While there are several sorting methods which are well established for coarser grain fractions which are being applied with great success, sorting of fine and finest grain sizes is limited to the froth flotation process. But besides froth flotation there is a second interface-controlled separation process, namely electrostatic separation. This method has not yet become established in filler-processing due to the fact that grain sizes