Insights into the use of green leaching systems based on glycine for the selective recovery of copper

Finding strategies that promote sustainability in the recovery of metals with industrial applications is imperative to reduce costs and mitigate environmental impacts. The use of environmentally friendly reagents such as glycine is being widely investigated due to the benefits that its application entails from an industrial, economic, and environmental perspective. We sought through this study to advance in the application of glycine leaching systems for the recovery of copper from different wastes and minerals while determining the optimal conditions for its recovery. Experimental results showed that among the 3 feedstocks tested (two mining wastes and one sulfide mineral) under the established operating conditions (room temperature and different alkaline pHs), the best copper recovery was obtained with the most oxidized waste at pH 9.5, which allowed a 100% of copper recovery along with low leaching of Fe and As. Furthermore, the characterization of its final post-leaching residue showed phytostimulant properties. Unfortunately, these selected conditions did not yield favorable results for the sulfide mineral and the less oxidized wastes. In this case, further research will be necessary to achieve higher metal recoveries.