An Integrated Strategy and Process for Recovery of Germanium from Metallurgical By-Products and Waste Streams

Germanium is a strategic material essential for electronics, optics, and solar cell applications. The U.S. relies on imports to satisfy over half of its germanium demand; domestic extraction of germanium would reduce market volatility and support independent growth. Germanium does not commonly form ores in mineable quantities but can become enriched in metallurgical waste streams. The present study involves a multi-staged hydro- and pyrometallurgical process for the recovery of germanium from metallurgical wastes. Chlorination and volatilization present a simple and effective pretreatment method of concentrating germanium in an aqueous solution. Following pretreatment, germanium is adsorbed onto magnetite particles, which are then magnetically separated from solution with high efficiency. Adsorption kinetics have been modeled, and competitive adsorption experiments with a common gangue element have been completed. Chlorination experiments involving the volatilization of germanium tetrachloride from a synthetic charge as well as a fumed slag sample have been completed. The influence of various surface functionalization’s on magnetite’s germanium uptake has been investigated. Additional work quantifying the selectivity of magnetite particles for germanium in multicomponent solutions is ongoing, with the goal of optimizing the final purification step.