Ecofriendly leaching agents for copper extraction—An overview of amino and organic acid applications

The green transition’s push for electrification has substantially increased the demand for copper, making it a critical raw material. This extravagant demand has made it profitable to extract copper from low-grade sulfide ores, which contain less than 0.3wt% copper. However, processing such low-grade ores requires extensive amounts of chemicals, raising environmental concerns. Thus, several investigations have been conducted on non-traditional lixiviants for copper extraction. Surprisingly, few studies have comprehensively reviewed this area to provide a comprehensive understanding and highlight gaps. This review analyzes investigations that have worked on the leaching process of copper into solutions using environmentally friendly reagents, particularly organic acids and amino acids, and compare them to conventional inorganic acids and examines recent advancements in ecofriendly leaching agents, specifically their application in copper leaching. The primary objective is to highlight the significance of these green reagents in mobilizing copper from solid to solution phases. It was highlighted that factors, such as mineralogy, mechanical activation, impurities, particle size, temperature, and initial concentration of the leaching agent, influence the leaching efficiency of organic and amino acids from primary and secondary copper resources. These variables interact in more complex ways than those encountered with conventional leaching methods. Research in this area has shown promising results, both in terms of extraction efficiency and reduced environmental impact, making it an exciting and essential area for further exploration and development. This shift towards using nonconventional lixiviants represents a significant step forward in the quest for more sustainable and environmentally responsible mining practices and recycling processes.