Abstract: A continuous high speed grinding and disperser mill and classifier for fluids is enclosed. The mill permits a high flow rate and thus does not require cooling. It comprises an enclosed vessel having an annular wear ring in the approximate center of the vessel, a shaft rotatable about a vertical axis extending into the vessel terminating at an end in the approximate center of the vessel, an impeller attached to the end of the shaft adapted to rotate within the wear ring, the impeller being in the form of a circular disc with a plurality of shear blades at the periphery producing a high shear zone between the blades and the wear ring. An inlet is provided in the vessel directly below the impeller on the vertical axis and an outlet in the vessel positioned at a predetermined height directly above the impeller on the vertical axis such that a flow of fluid from the inlet to the outlet passes through the high shear zone. Means are provided to rotate the shaft and impeller.

Abstract: A process is disclosed for preparing a slurry of titanium dioxide having a solids content of at least 60%. In the past titanium dioxide pigment slurries have been prepared by mixing titanium dioxide powder, water and additives in a batch mixer, however, this is a lengthy process and generally results in some agglomeration of the particles. The present process comprises the steps of mixing titanium dioxide pigment, at least one dispersant additive and water to a first mixture having a solids content of at least about 60%, pumping the first mixture through a disperser mill to produce a second mixture free from agglomerates.