Abstract: A ball-tube mill in which an inclined wall dividing the mill into coarse and fine grinding chambers occupied by grinding bodies has through holes for the passage of the material being ground provided in a portion of contact of the surface of the inclined wall with the grinding bodies present in the coarse grinding chamber. The through holes have a length much greater than their width with their elongated side running in parallel with an outer contour of the inclined wall.

Abstract: A ball tube mill in which an inclined wall dividing a housing of the mill into coarse and fine grinding chambers is fabricated from rigidly interconnected rods forming therebetween through slots for the passage of the material being ground. Part of each slot in the area of contact of the inclined wall with the grinding bodies at the side of the fine grinding chamber has a width smaller than the part of each slot at the remaining portion of the inclined wall at the side of the fine grinding chamber.

Abstract: A ball tube mill has a housing with an inlet and an outlet for material to be comminuted accommodates annular wall plates spaced at a predetermined distance from each other, arranged at an angle to the longitudinal axis of the housing, and having the form of an ellipse. The space between the adjacent annular wall plates is somewhat greater than D/tan .alpha., where D is the inside diameter of the housing, and .alpha. is the inclination angle of the annular wall plate to the longitudinal axis of the housing.

Abstract: A ball-tube mill includes a rotatable drum enclosed at the opposite sides by bottoms having a charging port and a discharge port, the drum accommodating an even number of perforated walls having the form of an ellipse, arranged at an angle to the centerline of the drum, and offset along the like axes of the ellipse one relative to another to define milling chambers occupied by grinding bodies. The bottoms are inclined to the longitudinal centerline of the drum at an inclination angle equal to the angle of inclination of the perforated walls, each bottom and one of the perforated walls being inclined in pairs to the opposite directions, the bottoms and the perforated walls being successively offset along the like axes of the ellipse one relative to the other at an angle .beta.=360.degree.:n, where n is the total number of bottoms and perforated walls.

Abstract: A ball tube mill includes a rotatable housing with a lined inside surface and end cover plates having an inlet hole and an outlet hole and accommodating at an angle to its longitudinal axis at least one perforated wall dividing the housing into coarse and fine grinding chambers charged with grinding bodies. The lined inside surface of the chambers has the form of truncated cones facing by their large bases the perforated wall, the angle of inclination of a generating line of the truncated cones equalling the angle of the slope of the grinding bodies present in the respective chamber, the volume of the coarse grinding chamber being smaller than the volume of the fine grinding chamber.