Valorization of Low-Grade and Secondary Copper Resources through Innovative Hydrometallurgical Techniques

The global copper industry is increasingly reliant on the processing of low-grade primary ores and complex secondary resources, such as industrial slags, flotation tailings, and electronic waste, due to the depletion of high-grade deposits and mounting environmental pressures. This review synthesizes recent advancements in the hydrometallurgical valorization of these challenging materials, focusing on innovative techniques for pretreatment, leaching, and downstream processing. A critical analysis reveals that advanced pretreatment is essential for economic viability. Mechanical strategies, such as High-Pressure Grinding Rolls (HPGR), enhance mineral liberation and improve energy efficiency, while chemical pretreatments, particularly chloride-assisted curing, have been proven to dramatically accelerate the dissolution kinetics of refractory copper sulfides like chalcopyrite. This paper examines the shift from conventional sulfuric acid to alternative lixiviant systems. Bioleaching is highlighted as a robust, low-cost technology for sulfide ores, whereas the application of 'green' lixiviants, notably alkaline glycine, demonstrates exceptional selectivity and environmental benefits for complex secondary wastes. Key rate-limiting factors are discussed, with ore mineralogy and the reactivity of gangue and clay minerals identified as the most significant challenges, impacting reagent consumption, heap permeability, and impurity management. The future outlook points towards the development of integrated, sustainable flowsheets that combine biological, chemical, and physical processes. The strategic use of novel reagents, coupled with advanced process modeling and control, is crucial for creating a circular economy for copper from these vital unconventional resources.

کلیدواژه ها:

copper ، leaching ، sulphuric acid ، slag ، glycine