Abstract: Method for producing silicon which is suitable as a starting material for producing a silicon melt for the fabrication of silicon blocks or silicon crystals, comprising the following steps: introducing a gaseous mixture of monosilane and hydrogen into a reactor, thermal degrading the gaseous mixture for forming silicon powder, separating the formed silicon powder produced from the gaseous mixture, and mechanical compacting the separated silicon powder with compacting rollers which having a roller jacket consisting of a ceramic material selected from graphite, glass and silicon nitride.

Abstract: In a reactor for the decomposition of a silicon-containing gas, provision is made, to avoid silicon deposition on an inner wall of a reactor vessel, for at least one catalytically active mesh to be provided within a reaction chamber between at least one gas feed line and the inner wall (4). The mesh accelerates the thermal decomposition of the gas and reduces the deposition of silicon on the inner wall. Also described is a process for the preparation of silicon using the reactor according to the invention and the use in photovoltaics of the silicon prepared.

Abstract: Compacting device for the low-metal compaction of a powder with a casing which at least in part surrounds a working chamber, with a feed arrangement arranged on the casing and feeding a powder, which is to be compacted, into the working chamber, with at least a compacting roller which is rotatably arranged in the working chamber, comprises a roller jacket and, together with an opposing wall, forms a compacting gap for compacting the powder therein, characterised in that the at least one compacting roller consists of ceramic, at least on the roller jacket.

Abstract: Method for manufacturing a reactor for separating a gas containing silicon, comprising the following stages: preparation of a substantially tubular reactor blank with an inner wall and an outer wall, and application of a separating layer containing a powdery separating medium, at least onto the inner wall of the reactor blank. The reactor with the separating layer applied thereon offers simple and effective protection of the inner wall from deposited silicon powder. The separating layer and the silicon powder deposited thereon can easily be removed mechanically, without the inner wall being damaged.