Abstract
The global demand for critical elements such as gallium (Ga) and germanium (Ge), and the shift toward circular mining has accelerated the development of new extraction and recovery processing these metals from industrial solid residues. This transition is driven by a substantial surge in demand for advanced technologies and the depletion of primary ore. Consequently, industrial solid residues, particularly zinc processing residues, smelter slags, flue dusts, and coal fly ash, are emerging as viable alternative sources. These residues incorporate Ga and Ge through isomorphic substitution in phases such as ferrites, silicates, and glassy aluminosilicates, and are enriched by industrial processes, often surpassing the grades found in primary ores. This review synthesizes recent advances in hydrometallurgical routes for the recovery of Ga and Ge. Leaching strategies employing acidic and alkaline media, under atmospheric, pressure, and ultrasound-assisted conditions, are discussed with respect to dissolution behavior and process efficiency. Subsequent product solution purification approaches, including solvent extraction, ion exchange with functionalized resins, and selective precipitation, are assessed for their selectivity and operational robustness. The review identified five barriers to industrial deployment, including feedstock heterogeneity, silica gel formation, Fe/Al/Si impurity burden, limited data on reagent recycling, and scarce pilot-scale data relevant to industry. Future progress requires integrated flowsheets, standardized reporting of co-leached impurities and overall recoveries, TEA/LCA, and digital-twin-enabled process control.
Recommended Citation
E. V. Oteng et al., "A Review Of Gallium And Germanium Recovery From Industrial Solid Residues," Minerals Engineering, vol. 248, article no. 110594, Elsevier, Nov 2026.
The definitive version is available at https://doi.org/10.1016/j.mineng.2026.110594
Department(s)
Mining Engineering
Second Department
Materials Science and Engineering
Third Department
Chemistry
Publication Status
Full Text Access
Keywords and Phrases
Gallium; Germanium; Industrial solid residue; Ion exchange; Leaching; Precipitation; Solvent extraction
International Standard Serial Number (ISSN)
0892-6875
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 Elsevier, All rights reserved.
Publication Date
01 Nov 2026
Comments
U.S. Department of Energy, Grant AL-12-350-001