Abstract: 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.sup.-1 to 1.10.sup.-2 mm Hg while elevating temperature to from 25.degree. to 1,150.degree. C. at variable heating rates ranging from 0.5.degree. to 20.degree. 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.degree. to 100.degree. C. at variable cooling rates ranging from 0.05.degree. to 15.degree. 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.

Abstract: According to the invention a process is proposed for purifying low-melting metals from impurities, residing in that a melt of a low-melting metal is treated with an aqueous solution of an inorganic acid or an alkali in the presence of organic compounds with ionogenic groupings.The proposed invention enhances the purity degree of the low-melting metal being purified and at the same time reduces the losses thereof.

Abstract: A process for producing high-purity indium which comprises vacuum melting of the metal in two stages: in the first stage at a temperature of from 850.degree. to 940.degree. C. for 1-5 hours; in the second stage at a temperature of from 950.degree. to 1,100.degree. C. for 0.5-2 hours. Thereafter, the metal is subjected to an electrochemical refinement in a hydrochloric acid solution, while the residue of indium evolved on the cathode is remelted by introducing into molten indium at a temperature of from 160.degree. to 400.degree. C.

Abstract: A process for recovering gallium from alkali aluminate solutions which consists in that the starting alkali aluminate solution is neutralized to a concentration of the caustic alkali of from 0.1 to 10 g/l, whereafter the neutralized liquor is evaporated to a concentration of the caustic alkali therein of from 30 to 150 g/l. Then the evaporated solution is corrected to obtain the ratio between the alkali metal oxide and alumina of above 2.0. The corrected solution is treated with a liquid alloy of gallium containing an element possessing an oxidizing potential exceeding that of gallium to give a concentrate containing more than 90% of gallium by mass, wherafter gallium of a higher purity grade is recovered from the resulting concentrate by the electrochemical method.