The lifetime of a fluidized bed reactor containing silicon particles, for the production of chlorosilanes is greatly extended by armoring at least a portion of the reactor shell interior wall with expanded metal coated with a cement containing ceramic particles.

A system for purifying trichlorosilane that can prevent re-contamination by the dissociation of an adduct occurring in association with the conversion of high boiling point compounds or the remaining of impurities due to an equilibrium constraint is provided. Trichlorosilane containing impurities serving as a donor or an acceptor in silicon crystals is supplied to a multistage impurity conversion step. These impurities in the trichlorosilane are converted into high boiling point compounds in the presence of a distillation aid. A plurality of impurity conversion step sections (10.sup.1 to 10.sup.n) are connected in series, and any of the impurity conversion step sections comprises a reception section a for the trichlorosilane from the preceding stage section, an introduction section b for the distillation aid, a transmission section c for the trichlorosilane to the subsequent stage section, and a drain section d that discharges a remainder out of the impurity conversion step section.

Yield of products of increased purity from a fluidized bed reactor where silicon is produced or consumed is enhanced by purging with inert gas, purging with hydrogen gas, and purging with a chlorosilane-containing gas. The purging with hydrogen is conducted at an elevated temperature.

The present invention relates to an apparatus for producing trichlorosilane from tetrachlorosilane in an efficient manner. The apparatus includes an inlet through which reaction raw materials including a metal silicon powder dispersed in liquid tetrachlorosilane enter, a hole through which a gaseous reaction raw material is fed, an outlet through which reaction products including trichlorosilane exit, a tubular reactor in which the reaction raw materials entering through the inlet react with each other during flow, and means for impeding the flow of the fluids to cause collision of the fluids during flow.

The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.

A method for preparing trichlorosilane according to an embodiment of the present invention comprises the steps of: supplying surface-modified metal silicide and metal grade silicon to a reaction unit; supplying silicon tetrachloride and hydrogen to the reaction unit; and supplying a product, which is generated by a reaction of metal grade silicon, silicon tetrachloride, and hydrogen in the presence of metal silicide in the reaction unit, to a separation unit, and separating a trichlorosilane component. In cases where a silicon tetrachloride hydrochlorination reaction is performed using the method for preparing trichlorosilane according to the embodiment of the present invention, the yield of trichlorosilane can be raised.

Provided is a method of preparing trichlorosilane, more particularly, a method of preparing trichlorosilane which trichlorosilane can be obtained with an improved yield using a catalyst-supported silicon.

A system for purifying trichlorosilane that can prevent re-contamination by the dissociation of an adduct occurring in association with the conversion of high boiling point compounds or the remaining of impurities due to an equilibrium constraint is provided. Trichlorosilane containing impurities serving as a donor or an acceptor in silicon crystals is supplied to a multistage impurity conversion step. These impurities in the trichlorosilane are converted into high boiling point compounds in the presence of a distillation aid. A plurality of impurity conversion step sections (10.sup.1 to 10.sup.n) are connected in series, and any of the impurity conversion step sections comprises a reception section a for the trichlorosilane from the preceding stage section, an introduction section b for the distillation aid, a transmission section c for the trichlorosilane to the subsequent stage section, and a drain section d that discharges a remainder out of the impurity conversion step section.

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.

The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.