Rhone-poulenc Specialites Chimiques

Rhone-poulenc Chimie

Philippe Nataf

Bernard Boudot

Serge Jacubert

Francoise Seon

Eric Le Roux

Shaped articles, e.g., bars, of semiconductor-grade, ultra-pure silicon, are facilely and efficiently produced by thermally decomposing/pyrolyzing a monosilane feedstream on a red-heated silicon support member, whereby high purity silicon is deposited thereon, and thence recycling the majority of the by-product reaction admixture into said monosilane feedstream.

Production of shaped articles of ultra-pure silicon

Shaped articles, e.g., bars, of semiconductor-grade, ultra-pure silicon, are facilely and efficiently produced by thermally decomposing/pyrolyzing a monosilane feedstream on a red-heated silicon support member, whereby high purity silicon is deposited thereon, and then recycling the majority of the by-product reaction admixture into said monosilane feedstream.

The metals of Groups (IV)(B) or (V)(B) of the Periodic Table, or of the lanthanide series, e.g., titanium metal, are conveniently produced, notably in powder form, by reducing a salt of such a metal by contacting same with liquid admixture comprising lithium metal maintained dispersed in a bath of molten salts.

Production of metals by metallothermia

Lithium metal is continuously prepared, in specially adapted electrolytic cell, by (i) continuously electrolyzing a mixture of molten salts including lithium chloride, said mixture comprising the medium of electrolysis, (ii) continuously withdrawing admixture of product lithium metal with said mixture of molten salts, and (iii) continuously discharging formed chlorine gaseous phase therefrom, wherein the medium of electrolysis is maintained at a temperature ranging from the melting point of said mixture of molten salts, at the eutectic composition thereof, to 400.degree. C., and said gaseous chlorine phase is maintained at a temperature not exceeding 300.degree. C.

Continuous production of lithium metal by electrolysis of lithium

A powder of elemental silicon having high purity and a density in excess of about 0.6 g/cm.sup.3, preferably ranging from 0.8 to 1.2 g/cm.sup.3, and which is non-amorphous as determined by X-ray analysis, is facilely prepared by thermally decomposing a silane feedstream at a decomposition reaction temperature ranging from 500.degree. to 700.degree. C., preferably from 500.degree. to 600.degree. C.

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Paris, France

Philippe Nataf