Germanium oxide purification

The apparatus and the procedure are the same as used for the purification of the crude germanium oxide. However, no Clg is added since the starting GeOg is arsenic-free. It is, of course. 

Purification actually starts with the precipitation of the hydrous oxides of iron, alumina, siUca, and tin which carry along arsenic, antimony, and, to some extent, germanium. Lead and silver sulfates coprecipitate but lead is reintroduced into the electrolyte by anode corrosion, as is aluminum from the cathodes and copper by bus-bar corrosion. 

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