A process for removal of impurities, in particular of dopants, from chlorosilanes which includes the following steps: (a) heating a deposition surface (3); (b) contacting the heated deposition surface (3) with at least one gaseous chlorosilane mixture, the gaseous chlorosilane mixture including at least one chlorosilane and at least one impurity, in particular at least one dopant; (c) at least partially removing the impurity, in particular the dopant, by forming polycrystalline silicon depositions on the deposition surface (3), the polycrystalline silicon depositions being enriched with the impurity, in particular with the dopant; (d) discharging the purified gaseous chlorosilane mixture; (e) contacting the heated deposition surface (3) with an etching gas to return the polycrystalline silicon depositions and the impurity, in particular the dopant, into the gas phase to form a gaseous etching gas mixture; and (f) discharging the gaseous etching gas mixture.

A cracking process for a reaction distillation of chlorosilane slurry includes feeding a chlorosilane slurry into a phase separator, drying a solid phase, feeding a chlorosilane polymer into a plate distillation column, returning kettle materials of the plate distillation column, and dividing a material produced from a top of the column. The process adopts an ionic liquid catalyst, which is environmentally friendly and reusable. The cracking and distillation of chlorosilane polymer are carried out simultaneously to shorten the time and increase the utilization rate of raw materials, which can reduce energy consumption and save costs and facilitate industrial production. A plate column is used as a distillation column, in which the two phases of the gas and liquid are sufficiently contacted. Therefore, the transfer of mass and heat is good, the production capacity is good, and the tower is not easily blocked, thereby making it easy to clean.

The invention relates to a process for the preparation of trichlorosilane (HSiCl3) which comprises the reaction of tetrachlorosilane (SiCU) with hydridosilanes in the presence of a catalyst.

Boron, phosphorus, arsenic, antimony and other impurities are at least partially removed from a mixture containing at least one chlorosilane and/or organochlorosilane by a) contacting the liquid mixture with a carrier material functionalized with an amidoxime of the general structural formula (I),

##STR00001##

where CAR=carrier material and R.sup.1, R.sup.2 are independently of one another H, alkyl, alkenyl, aryl, alkylaryl; and b) optionally removing the functionalized carrier material.

A process for obtaining hexachlorodisilane and uses for the same. The process includes contacting at least one partially hydrogenated chlorodisilane of general formula H.sub.xSi.sub.2Cl.sub.(6-x) where x is from 1 to 5 in the liquid state with a solid non-functionalized adsorber material that is selected from the group comprising silicates, aluminosilicates, organic polymer and/or combinations thereof. The process also includes optionally separating the hexachlorodisilane and/or optionally separating the adsorber material.

To prevent solidified aluminum chloride from adhering to and accumulating on a pipe and also prevent stress-corrosion cracking in the pipe, a method for producing trichlorosilane includes a cooling step of cooling a discharge gas that is discharged from a fluidized-bed reactor and that contains the trichlorosilane, the cooling step involving causing a fluid to flow through a space (4) inside a side wall (3) of a pipe (10), the pipe being a pipe for discharging the discharge gas from the fluidized-bed reactor, in such a manner that the side wall (3) has a surface (1a) having a temperature of not lower than 110° C.

Chlorosilanes are produced in exalted yield in a fluidized bed process when the reactor hydraulic diameter, Sauter particle diameter, and superficial gas velocity are used to define a parameter space as a function of Reynolds number and Archimedes number.

In order to produce high-purity trichlorosilane by removing methyldichlorosilane from a mixture (S) containing methyldichlorosilane (CH.sub.3HSiCl.sub.2), tetrachlorosilane (SiCl.sub.4), and trichlorosilane (HSiCl.sub.3) in the method for producing trichlorosilane of the present invention, a procedure is employed in which chlorine atoms are redistributed between methyldichlorosilane and tetrachlorosilane through catalytic treatment for conversion into trichlorosilane and methyltrichlorosilane (CH.sub.3SiCl.sub.3). Methyldichlorosilane (boiling point: 41° C.) having a boiling point close to that of trichlorosilane (boiling point: 32° C.) to be purified is converted into methyltrichlorosilane (boiling point: 66° C.) having a higher boiling point through redistribution of chlorine atoms between methyldichlorosilane and tetrachlorosilane, achieving easy removal of impurities.

The invention relates to an improved process to manufacture TCS in a polysilicon plant based upon combining a high temperature FBR process reacting metallurgical grade silicon, hydrogen, and silicon tetrachloride (STC) to make trichlorosilane (TCS) and a high temperature thermal converter to hydrogenate STC to TCS and hydrogen chloride.

A process for preparing a product including a monohydrogentrihalosilane is disclosed. The process includes the steps of: 1) initially charging a reactor with a contact mass including both fresh silicon and recycled contact mass, where the recycled contact mass is obtained from during or after a production phase of an inorganic Direct Process reaction for production of a monohydrogentrihalosilane; and thereafter 2) feeding to the reactor a hydrogen halide and additional fresh silicon, thereby forming the product.