Gallium and germanium recovery from domestic sources.
Salt Lake City, UT: U.S. Department of the Interior, Bureau of Mines, RI 9419, 1992 Jan; :1-26
To decrease reliance on foreign sources for the strategic and critical metals gallium and germanium, the U.S. Bureau of Mines identified and developed processing technology for two domestic sources of these metals: a Tennessee zinc residue and a Utah ore. Sulfuric acid (H2SO4) solutions were used to solubilize gallium and germanium in both sources. Statistically designed experiments showed that the most important parameter for high metal extraction from zinc residue was the H2SO4 concentration. At a concentration of 2.9M H2SO4, 95 pct of the gallium was extracted, and at a concentration of 0.6M H2SO4, 73 pct of the germanium was extracted. Controlled H2SO4 concentration was also the key for metal extractions (97 pct Ga, 87 pct Ge) from the Utah ore. Such control was achieved using a two-stage countercurrent leach circuit. Testing showed that the insoluble germanium in both the residue and ore was tied up with silica. Several methods for overcoming this problem are given. To recover gallium and germanium from the leach solutions, the solvent extractants octylphenyl acid phosphate (OPAP) (for gallium) and lix 63-OPAP (for germanium) were identified. These extractants were tested in separate, continuous, solvent- extraction circuits, yielding a gallium recovery of 94 pct and a germanium recovery of more than 90 pct.
Metal-compounds; Metals; Metallurgical-processes; Germanium-compounds; Chemical-extraction; Chemical-processing
IH; Report of Investigations
NTIS Accession No.
Salt Lake City, UT: U.S. Department of the Interior, Bureau of Mines, RI 9419