Aluminum Smelting Carbon Dust as a Potential Raw Material for Gallium and Germanium Extraction

Gallium and germanium are highly important elements used in different high-tech areas, and new secondary raw materials for its extraction are the subject of a thorough search. In this study, germanium is found in the wastes from the Hall-Heroult process for the first time. The mechanism of gallium and germanium circulation in the aluminum reduction cell is discussed. Four types of materials, namely carbon dust, flotation tailings, carbon concentrate, and ash, were examined. It was found that a temperature of 900 °C is sufficient for the complete combustion of the carbon concentrate. The gallium concentration in the ash may reach up to 4.0 kg/ton. The germanium extraction to sublimates reaches up to 90%. Carbon concentrate being the processing product of carbon dust from an aluminum reduction cell is a promising secondary raw material for germanium and gallium extraction.