This paper review presents a comparison between conventional leaching and advanced photochemical leaching processes and their potential for use in chalcopyrite leaching. Likewise, it presents an analysis of the differences between the advanced leaching processes, photoleaching and radical-leaching, indicating that the photochemical mechanisms (photooxidation/photoreduction and generation of radical oxygen species (ROS) and radical sulfur species (RSS)) would improve the oxidative dissolution of chalcopyrite, taking advantage of the high oxidizing power of free radicals. Initial experimental results of solar-assisted radical-leaching on chalcopyrite are presented, demonstrating that sulfate radicals (SO₄⁻) allow copper to be leached at a rate 4.7 times higher than in the absence of radicals and sunlight. With these results, a radical-leaching process is presented for the first time, with a perspective toward the future development of a new hydrometallurgical route: solar-assisted radical-leaching.

This research investigates the fundamental impact of the photochemical effect of sunlight on the oxidative dissolution of chalcopyrite (CuFeS₂) in sulfate-oxidizing media under mild conditions and circumneutral pH. Beyond its traditional role as a thermal or electrical energy source, this study explores solar light (UV-Vis-NIR) as a photochemical reagent capable of driving the in situ generation of reactive sulfur species to assist the conventional oxidative dissolution pathway. The interaction at the mineral–solution interface under UV-Vis radiation was investigated using a laboratory-scale solar-assisted PS/TiO₂/UV-Vis-NIR system, employing persulfate (S₂O₈²⁻) as a radical precursor and TiO₂ (Aeroxide^® TiO₂ P25) as a photocatalyst. The findings demonstrate that solar exposure increases the system’s electrochemical potential and induces pH changes, which are critical for overcoming the inherent refractoriness of CuFeS₂ at near-neutral pH. This study demonstrates that integrating UV-Vis-NIR radiation serves as a synergistic catalyst in oxidative hydrometallurgical processes, enhancing Cu extraction yields to 14%–19% within 5 h of exposure at the laboratory scale. The use of natural light could offer a synergistic pathway to augment the efficiency of cleaner leaching technologies. These findings suggest that solar radiation could serve as a promising assistant to address kinetic limitations during the oxidative dissolution of complex sulfide ores under ambient conditions.