Process for producing high-purity gallium

摘要

A process for producing high-purity gallium from gallium-arsenic containing wastes resulting from the manufacture of semiconductors which comprises a vacuum-thermal decomposition of said wastes under a residual pressure of from 1.10-1 to 1.10-2 mm Hg while elevating temperature to from 25 DEG to 1,150 DEG C. at variable heating rates ranging from 0.5 DEG to 20 DEG C./min. The vacuum-thermal decomposition of the wastes is accompanied by sublimation of arsenic which is condensed. The resulting melt of gallium is cooled to a temperature of from 50 DEG to 100 DEG C. at variable cooling rates ranging from 0.05 DEG to 15 DEG C./min. Then the melt of gallium is filtered at the cooling temperature of the melt. The filtered gallium melt is subjected to a hydrochemical treatment. The melt of gallium having passed the hydrochemical treatment is subjected to a fractional multi-stage crystallization to crystallize gallium in an amount of from 60 to 95% by mass of its initial charge in each stage; the metal residues enriched with impurities are recycled from each subsequent stage to each preceding one.