Chemical process for recovering alkali metals and alkaline earth metals

摘要

Halides of alkali metals and of alkaline earth metals ("metals") are reduced by gallium, indium or thallium ("reducing metals") at temperatures below their boiling points at vapour pressures at which the gaseous monohalides of the reducing metals are formed. The amount of the reducing metals is calculated to be large enough both for the reduction of the metal halides and also for the simultaneous dissolution of the metals formed. For example: MgCl2(s) + 2Ga(1) = 0 Mg 0 (1)GaCl(g); 900 DEG K, 0.02 mm Hg From the melt formed, the metal is distilled off and condensed, and the metal-free reducing metal is reused for the metal halide reduction. The monohalide of the reducing metal is oxidised, the reducing metal oxide is reduced to the reducing metal and this is also reused in the halide reduction. The continuous process conditions, the loss-free circulation of the reducing metal, the utilisation of the heat of exothermic processes and a minimal requirement of electrical transport energy enable a high economic efficiency of the recovery of alkali metals and alkali earth metals according to the invention.