Acid Leaching Extraction of Ga and Ge

The U.S. Bureau of Mines recently investigated sulfuric acid leaching to extract gallium and germanium from a zinc processing residue containing 0.32% Ga and 0.46% Ge. These metals can be extracted by leaching with sulfuric acid alone or by leaching with sulfuric acid and sulfur dioxide. A low temperature roasting treatment also aids in extracting 20% more germanium. A high percentage of the residue’s remaining zinc and cadmium is extracted using either technique.