Process for treating exhaust gases from a unit for the fabrication of optical fiber preforms, for recovering germanium

摘要

In an optical fiber preform production waste gas treatment process, germanium is precipitated from a liquid, formed from the waste gas, by adding magnesia (MgO). Preferred Features: The waste gas, containing germanium tetrachloride (GeCl4), is reacted with caustic soda to form a liquid waste containing germanium and hypochlorite, the latter being reduced by formic acid addition.