NOVELTY - A disproportionation reactor feed comprising silane and silicon tetrachloride is reacted in a disproportionation reactor (114). Chemical vapor deposition (CVD) of the mixture from the disproportionation reactor is carried out by a CVD reactor (136) to deposit silicon on a substrate within the CVD reactor. Silicon is then recovered from the CVD reactor.    USE - Production of silicon e.g. polysilicon for semiconductors and photovoltaic applications e.g. solar power applications.    ADVANTAGE - The method enables efficient and economical production of silicon by CVD. The reaction by-products are recycled for use within the systems and processes without recovery and external processing of the by-products. The process provides savings in both capital and operating costs.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for production of silicon comprising: performing a chemical vapor deposition on a mixture comprising trichlorosilane by a chemical vapor deposition reactor; recovering silicon from the chemical vapor deposition reactor; releasing from the chemical vapor deposition reactor an effluent mixture comprising hydrogen, silicon tetrachloride, and one or more of hydrogen chloride, dichlorosilane, and trichlorosilane; and either converting hydrogen chloride in the effluent mixture from chemical vapor deposition reactor to chlorosilanes by a post-CVD reactor in a hydrogen chloride reactor, or cooling the effluent mixture from the chemical vapor deposition reactor by a first cooling system.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a system used for preparing silicon.    Pre-disproportionation reactor silane/chlorosilane mixer (106)    Pre-disproportionation reactor temperature controller (110)    Disproportionation reactor (114)    Post-disproportionation reactor silicon tetrachloride separator (118)    Pre-CVD reactor vaporizer (128)    Pre-CVD reactor mixer (132)    CVD reactor (136)    Post-CVD reactor coolers (142,146)    Post-CVD reactor compressor (144)    Post-CVD reactor hydrogen separator (150)    Pre-disproportionation reactor chlorosilane mixer (162)    Post-CVD reactor decanter (169)