Recovery Germanium from the Hydrolysis Filtrate of Germanium Tetrachloride

A new method for recovering germanium from the hydrolysis filtrate of germanium tetrachloride was sutdied.The magnesium compounds were introduced into hydrolysis filtrate in a certain proportion and sodium hydroxide(NaOH) or aqueous ammonia(NH3·H2O) were used to adjust pH value of the solution to 7～8 to make germanium precipitate in germanate form,then germanium in germanate was recovered in GeCl4 form by conventional distillation process.The results show that the precipitation rate of germanium in the hydrolysis filtrate can reach above 98% by precipitation.The optimum parameters of germanium in precipitation hydrolytic solution verified by experiments are that NaOH is used to adjust pH value of hydrolytic solution,pH value is equal to 7～8,MgCl2 or MgSO4 used as precipitation agents,Mg/Ge(molar ratio) is equal to 1.5∶1 and precipitation time 4 h.