Silicon production and processing employing a fluidized bed

Claim 1

In a process for producing elemental silicon in a high state of purity including the steps of: fluidizing with hydrogen a bed of finely divided particles of pure elemental silicon within a reaction zone maintained at from 750°-1350° C.; passing a vaporous silicon halide reactant stream through a conduit leading into the fluidized bed for reaction with a portion of said hydrogen, the halogen component being taken from the group consisting of a chloride, a bromide and an iodide, to deposit the resulting silicon reaction product on said product; removing vaporous reaction products from said reaction zone; and separately recovering the resulting larger-sized silicon particles formed in said zone; the improvement comprising: (a) pressurizing said reactant stream to 15 to 20 p.s.i. in said conduit; (b) semi-continuously adding seed crystals of silicon to said pressurized stream; then (c) passing the seed-containing reactant stream to a mixing chamber below the bottom region of said fluidized bed where it is combined with said hydrogen; and (d) passing the combined streams into said reaction zone through apertures sufficiently small to prevent larger particles from falling through.