Solvometallurgy: An Emerging Branch of Extractive Metallurgy

This position paper introduces the reader to the concept of solvometallurgy, the term used to describe the extraction of metals from ores, industrial process residues, production scrap, and urban waste using non-aqueous solutions. Here, non-aqueous is not used to imply anhydrous, but rather a low water content. The unit operations include solvent leaching, separation of the residue, purification of the leach solution by non-aqueous solvent extraction or ion exchange, and metal recovery by precipitation or electrolysis in non-aqueous electrolytes. Unlike hydrometallurgy, solvometallurgy minimizes water consumption and wastewater generation, combining leaching and solvent extraction into a single step for simplified processing. The use of green solvents is emphasized to ensure sustainability. Solvometallurgy offers advantages, particularly for ores rich in soluble silica, and stands as a complementary approach to pyrometallurgy and hydrometallurgy. Even though its Technology Readiness Level remains low (TRL = 3–4), solvometallurgy presents significant opportunities for research, development, and innovation towards near-zero-waste metallurgical processes with lower energy consumption.