Abstract: A method and apparatus for distillative separation of a mixture comprising three or more components including at least one low boiler, at least one medium boiler, and at least one high boiler, the method comprising feeding the mixture of three or more components to a first distillation column, removing the at least one high boiler as a bottom fraction from the first distillation column, feeding a top fraction of the first distillation column to a second distillation column, removing the at least one medium boiler via a sidestream takeoff from the second distillation column, removing the at least one low boiler as a top fraction from the second distillation column, and feeding a bottom takeoff stream from the second distillation column to the first distillation column as a reflux, wherein the first and the second distillation columns have vertical dividing walls.

Abstract: A method and apparatus for distillative separation of a mixture comprising three or more components including at least one low boiler, at least one medium boiler, and at least one high boiler, the method comprising feeding the mixture of three or more components to a first distillation column, removing the at least one high boiler as a bottom fraction from the first distillation column, feeding a top fraction of the first distillation column to a second distillation column, removing the at least one medium boiler via a sidestream takeoff from the second distillation column, removing the at least one low boiler as a top fraction from the second distillation column, and feeding a bottom takeoff stream from the second distillation column to the first distillation column as a reflux, wherein the first and the second distillation columns have vertical dividing walls.

Abstract: A polycrystalline granulated silicon is made of particles which have a density of greater than 99.9% of the theoretical solid density and therefore have a pore content of less than 0.1% and have a surface roughness Ra of less than 150 nm.

Abstract: Polycrystalline silicon is prepared by thermally decomposing a reaction gas comprising hydrogen and a silicon-containing gas in a reaction chamber containing heated silicon, depositing additional silicon thereon, and forming an offgas; and separating the offgas into a first fraction comprising trichlorosilane and lower boiling chlorosilanes, and a second offgas fraction comprising components having a higher boiling point than trichlorosilane; recycling the first offgas fraction to the reaction gas of a polycrystalline silicon deposition; and separating the second offgas fraction into tetrachlorosilane and a high boiler fraction of high boilers, optionally also containing some tetrachlorosilane, and supplying the high boiler fraction to the reaction gas of a silicon deposition and heating the reaction gas to a temperature which ensures that the high boiler fraction is present in gaseous form on entry into the reaction chamber of the deposition reactor.

Abstract: Polycrystalline silicon is prepared by thermally decomposing a reaction gas comprising hydrogen and a silicon-containing gas in a reaction chamber containing heated silicon, depositing additional silicon thereon, and forming an offgas; and separating the offgas into a first fraction comprising trichlorosilane and lower boiling chlorosilanes, and a second offgas fraction comprising components having a higher boiling point than trichlorosilane; recycling the first offgas fraction to the reaction gas of a polycrystalline silicon deposition; and separating the second offgas fraction into tetrachlorosilane and a high boiler fraction of high boilers, optionally also containing some tetrachlorosilane, and supplying the high boiler fraction to the reaction gas of a silicon deposition and heating the reaction gas to a temperature which ensures that the high boiler fraction is present in gaseous form on entry into the reaction chamber of the deposition reactor.

Abstract: A crusher for producing fine silicon fragments for semiconductor or solar applications from silicon fragments suitable for semiconductor or solar applications, comprises a plurality of crushing tools, the crushing tools having a surface made from a hard, wear-resistant material, wherein the crusher has a comminution ratio e of from 1.5 to 3.

Abstract: A crusher for producing fine silicon fragments for semiconductor or solar applications from silicon fragments suitable for semiconductor or solar applications, comprises a plurality of crushing tools, the crushing tools having a surface made from a hard, wear-resistant material, wherein the crusher has a comminution ratio e of from 1.5 to 3.

Abstract: A polycrystalline granulated silicon is made of particles which have a density of greater than 99.9% of the theoretical solid density and therefore have a pore content of less than 0.1% and have a surface roughness Ra of less than 150 nm.

Abstract: A process for preparing silicon granules with a chlorine contamination below 50 ppm by weight by deposition of elemental silicon on silicon particles in a fluidized-bed reactor. This reaction has a heating zone below a reaction zone. The silicon particles, in the heating zone, are fluidized by means of an inert silicon-free carrier gas to produce a fluidized bed and are heated by means of microwave energy. The silicon particles are reacted within the reaction zone, a reaction gas made up of a silicon source gas and the carrier gas. The average temperature of the reaction gas in the reaction zone, while the gas is perfusing the fluidized silicon particles, is maintained at less than 900.degree. C. The average temperature of the fluidized silicon particles in the reaction zone, while they are being perfused by the reaction gas, is maintained at greater than 900.degree. C.