Patent ID: 8557210

Claim:
An integrated plant process for the production of trichlorosilane, comprising the following steps: A) feeding hydrogen chloride to a fluidized bed reactor ( 1 ) charged with metallurgical grade silicon and reacting the hydrogen chloride with the metallurgical grade silicon in the fluidized bed reactor ( 1 ) at a temperature of 290° C. to 400° C. to form a gaseous chlorosilane product stream containing trichlorosilane; B) introducing a high boiler fraction containing high boilers, derived from a) the chlorosilane product stream of a plant process for production of trichlorosilane, b) the offgas of polycrystalline silicon production, or c) high boilers from both a) and b), into a saturator together with at least a portion of the hydrogen chloride fed to the fluidized bed reactor ( 1 ) in step A) to form a high boiler- and hydrogen chloride-containing mixture, and C) feeding the high boiler- and hydrogen chloride-containing mixture from the saturator in step B) to the fluidized bed reactor ( 1 ) and recovering a chlorosilane product stream with a greater amount of trichlorosilane than is recovered in the absence of feeding high boilers to the fluidized bed reactor ( 1 ), wherein when the high boiler- and hydrogen chloride-containing mixture contains high boilers from a gaseous chlorosilane product stream from a fluidized bed reactor for preparing trichlorosilane, the gaseous chlorosilane product stream is filtered to remove silicon dust such that the high boiler- and hydrogen chloride-containing mixture is free of silicon dust, and wherein the high boilers have a boiling point at standard pressure greater than the boiling point of silicon tetrachloride, and are composed of silicon, chlorine and optionally hydrogen, oxygen, and carbon.