Abstract: A method and apparatus for separating mixtures of different densities into a lighter phase and a heavier phase including a rotary drum providing a cylindrical settling sump at the outer wall, a displacement member rotatably located within the drum forming a settling sump between the displacement member and the drum wall, a discharge element for lighter phase material spaced radially inwardly from the settling sump, a discharge conductor for heavier phase material leading from the settling sump at the deepest location at the outer circumference of the drum, and a compressed air conduit connected to the discharge for heavier phase material aiding in the removal thereof, and vanes on the displacement member aiding in movement of the material through the drum.

Abstract: The invention relates to an apparatus and method for producing a free flowing coal suspension high in solids content. The coal is ground in at least two stages utilizing a mill having a calibrating effect in one stage and a mill without calibrating effect in another stage and adding a sub-quantity of viscosity reducing additive to the coal before each grinding. A drying of the coal or reconcentration of the suspension is not required. A roller mill operating on the principle of materials bed comminution is preferred as the non-calibrating mill in the first grinding stage and a rotating drum mill or a vibration grinding mill with rods as grinding bodies is preferred as the calibrating mill.