Copper Dissolution from Sulfide Ore with Deep Eutectic Solvents Based on Choline Chloride

Copper is a critical resource for the energy transition and the development of novel sustainable processes for its recovery must be a focus of research. The use of deep eutectic solvents (DES) is an alternative for the solvometallurgical extraction of copper from sulfide ores with low or zero water consumption. The objective of this research is to study the dissolution of low-grade copper sulfide ore (0.83% Cu) using deep eutectic solvents. Laboratory scale agitation leaching tests were performed using different DES based on choline chloride (ChCl), namely ChCl-ethylene glycol, ChCl-citric acid, and ChCl-urea, at different temperatures (25, 50, and 60 °C). The effect of water and hydrogen peroxide was also studied in some systems. The best copper extractions were achieved with ChCl-citric acid > ChCl-urea > ChCl-ethylene glycol, reaching ≈99% copper extraction in some cases. This mineral leaching process offers an alternative to the processing of sulfide minerals and could be a technique that allows the use of solvent extraction and electrodeposition facilities available at a metallurgical plant, with less water consumption than the traditional leaching process.