GB734144A - Purification of germanium tetrachloride - Google Patents

Abstract

Germanium tetrachloride containing impurities, notably arsenic, is purified by at least once agitating it with aqueous hydrochloric acid having a concentration of at least 8 and preferably 12 normal containing added chlorine and preferably saturated therewith, allowing the mixture to settle into two layers and subsequently separating the layers to recover purified germanium tetrachloride as the lower layer. The operation is preferably conducted at reduced temperatures. According to an example scrap germanium containing aluminium, gallium, arsenic, antimony, boron and silicon was chlorinated in a silica vessel to obtain germanium tetrachloride. To the latter was added 40 per cent by volume of chlorine saturated 12N hydrochloric acid, the mixture agitated and allowed to settle into layers. The lower layer of germanium tetrachloride was hydrolysed to the dioxide and reduced to the metal which contained about 1 part of arsenic per 2 million parts of germanium. The process may be continuous, germanium tetrachloride being introduced near the top of a packed column through which an upward flow of chlorine saturated hydrochloric acid solution is maintained. The tetrachloride inlet is at a point such that an acid layer can form above it and be withdrawn, whilst the acid inlet is such that a tetrachloride layer can form below it and be withdrawn.