Efficient Acid Leaching of Low Carbonate Copper Oxide Ore: A Focus on Impurity Minimization

Abstract

Recent focus on hydrometallurgical methods for non-sulfide copper ores prompted a study on leaching a copper oxide ore containing 2.22% Cu, 44.9% SiO₂, 6.94% Al, 6.61% Fe, 6.25% Mg, 3.67% Ca, and 1.7% Na with H₂SO₄ for gaining insight into the behavior of impurities in the leaching process. The effects of leaching time (30–180 min), acid concentration (0.25–2 M), and temperature (25–66°C) were discussed by considering the leaching efficiency of copper and impurities. Increasing the acid concentration increased the leaching efficiency of manganese, phosphorus, zinc, and copper. Leaching temperature minimally impacted copper leaching but significantly increased impurity extraction. Elevated temperature and acid concentration notably enhanced magnesium, manganese, and iron leaching. Optimal conditions yielded 92.98% copper extraction with minimal impurities in the pregnant leaching solution (PLS). Results of the thermodynamic modeling of PLS species showed that copper and calcium were the main H₂SO₄ consumers. These findings offer insights to mitigate acid consumption and impurity-related challenges in downstream stages like solvent extraction and electrowinning.