US 4,362,560 AGranted

Process for producing high-purity gallium

OwnerVladimir N. Abrjutin, Vyacheslav P. Ezhkov +8inventors

InventorsVladimir N. Abrjutin, Vyacheslav P. Ezhkov, Raisa V. Ivanova, Oleg N. Kalashnik, Vyacheslav A. Kirichenko, Alexandr V. Peredereev, Jury G. Pukhov, Arkady A. Belsky, Vladimir V. Kozhemyakin, Galina E. Masjuk

Life of this patent

Estimating the term…

patentgrep

Loading patent…

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. 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.

Claims7

Dependent claims

A process for producing high-purity gallium from gallium-arsenic-containing wastes resulting from the manufacture of semiconductors comprising:

a. decomposing said wastes in a vacuum-thermal process under a residual pressure of from 1.10.sup.-1 to 1.10.sup.-2 mm Hg and at a temperature rising from 25.degree. to 1,150.degree. C. on heating at a rate in the range of from 0.5.degree. to 20.degree. C./min, accomplishing sublimation of arsenic and the formation of a melt of gallium containing impurities resulting from the decomposition of said wastes;
b. condensing said sublimated arsenic;
c. cooling the melt of gallium obtained by said decomposition of wastes to a temperature of from 50.degree. to 100.degree. C. at a variable rate of from 0.05.degree. to 15.degree. C./min;
d. filtering said gallium melt at the cooling temperature of said melt;
e. hydrochemically treating said filtered melt of gallium;
f. fractionally crystallizing said melt in a multi-stage crystallization to crystallize said gallium;
g. the melt residues enriched with impurities being recycled from each process step to each preceding process step, and
whereby from 60 to 95%, by mass, of the starting gallium in each stage is recovered.

5 more elements

Dependencies are inferred from the claim text.