Abstract: Method and device for separating a fine-grained solid material into a fines fraction and a coarse fraction at a cut point size of below 50 .mu.m, preferably below approx. 10 .mu.m. The fine-grained solid is dispersed in a liquid capable of forming drops and this dispersion is forced into a defined sink flow with a superimposed rotational flow that is generated independently from the jink flow. The relationship between the two rates, namely the sink flow rate and the rotational flow rate, is dictated by the cut point size. The device includes a deflector wheel which has a direction of flow from the outside to the inside, and vanes are fitted in the wheel parallel to its rotational axis to form flow channels, whereby the feed dispersion is charged to the deflector wheel at its outer periphery.