Abstract: A separating apparatus for polysilicon has at least one screen plate, comprising a feed region for polysilicon, a profiled region having peaks and valleys, a region having screen apertures which adjoins the profiled region, and a takeoff region, wherein the screen apertures widen in the direction of the takeoff region, and a separating plate which is horizontally and vertically displaceable is arranged below the screen apertures.

Abstract: Polysilicon chunks or granules are classified into size fractions using a mechanical screen having a profiled surface having peaks and valleys, and terminating in widening slots through which a polysilicon size fraction falls. The device is effective and the slots are resistant to clogging.

Abstract: A separating apparatus for polysilicon has at least one screen plate, comprising a feed region for polysilicon, a profiled region having peaks and valleys, a region having screen apertures which adjoins the profiled region, and a takeoff region, wherein the screen apertures widen in the direction of the takeoff region, and a separating plate which is horizontally and vertically displaceable is arranged below the screen apertures.

Abstract: Polysilicon chunks or granules are classified into size fractions using a mechanical screen having a profiled surface having peaks and valleys, and terminating in widening slots through which a polysilicon size fraction falls. The device is effective and the slots are resistant to clogging.

Abstract: In a process for the material-abrading machining of the edge of a semiconductor wafer, the semiconductor wafer is resting on a rotationally movable table, is rotated about a central axis and is machined by a plurality of rotating machining tools. It is intended for each of the machining tools to abrade a specific quantity of material from the edge of the semiconductor wafer. The process is one in which the machining tools, during the course of a 360.degree.-rotation of the semiconductor wafer, are successively advanced toward the edge of the semiconductor wafer and ultimately simultaneously machine the edge of the semiconductor wafer. A machining tool which has just been advanced is intended to abrade a smaller quantity from the edge of the semiconductor wafer than a previously advanced machining tool. The machining of the edge of the semiconductor wafer with one machining tool is terminated at the earliest once the semiconductor wafer has rotated through 360.degree.