AGGLOMERATION OF SILICON POWDERS

摘要

According to a method for agglomerating silicon powders, the silicon powder is heated to a temperature of at least 250 ~C, preferably 1200 to 1500 ~C, usin g the effect of microwave radiation in the wavelength range 0.5 kHz to 300 GHz . Fine silicon dust with a particle size of less than 100.mu.m is preferably used as the starting material. Metal-containing and/or boron, phosphorus, arsenic or antimony-containing doping agents can be added to the silicon powder before or after the microwave treatment. The resulting granulate is optionally broken, milled and sifted. The invention also relates to a silico n granulate which can be produced by this method. Said granulate preferably ha s a porosity of 0 to 80 % and foreign phases or precipitates on the grain boundary of the monocrystals. The inventive silicon granulate can be used fo r producing silicon monocrystals or multicrystalline silicon blocks or for reacting with hydrogen chloride or halogenated hydrocarbons in fluidised bed s or shaft furnaces.