Patent ID: 7758839

Claim:
A 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, the method comprising the steps of: providing a reactor; introducing a gaseous mixture of a silicon-containing gas and an auxiliary gas into said reactor; thermally degrading said gaseous mixture with formation of silicon powder; separating said silicon powder obtained from said gaseous mixture to provide silicon powder material having a density of 10 g/dm 3 to 100 g/dm 3 and consisting of crystalline particles with a primary particle size of 50 nm to 500 nm; and mechanically compacting said separated silicon powder to provide compacted silicon powder material having a density of 200 g/dm 3 to 1200 g/dm 3 and consisting of aggregates with an aggregate size of 1000 nm to 10,000 nm with compacting rollers such that said compacted silicon powder is not contaminated with metal, each compacting roller having a roller jacket, said roller jacket consisting of a ceramic material selected from glass, graphite and silicon nitride.