Extraction of copper from copper-bearing biotite by ultrasonic-assisted leaching

Copper-bearing biotite is a refractory copper mineral found on the surface of the Zambian Copperbelt. Biotite is a copper oxide from which copper is extracted by various methods, especially by leaching. Leaching is the process of extracting a substance from a solid material dissolved in a liquid. To improve the efficiency of the leaching process by a more effective method, a new method called ultrasonic-assisted acid leaching is proposed and applied in this study. Compared with regular acid leaching, the ultrasound method reduced the leaching time from 120 to 40 min, and sulfuric acid concentration reduced from 0.5 to 0.3 mol·L−1. Besides, leaching temperature could be reduced from 75 to 45°C at the leaching rate of 78%. The mechanism analysis indicates that an ultrasonic wave can cause the delamination of a copper-bearing biotite and increase its specific surface area from 0.55 to 1.67 m2·g−1. The results indicate that copper extraction from copper-bearing biotite by ultrasonic-assisted acid leaching is more effective than regular acid leaching. This study proposes a promising method for recycling valuable metals from phyllosilicate minerals.