Enhancement of copper recovery by acid leaching of high-mud copper oxides: A case study at Yangla Copper Mine, China

Poor permeability, high mud and impurities contents, severe curing conditions and ore complexity are primary challenges faced by Yangla Copper Mine (YCM) during acid leaching, resulting in a poor 1% copper extraction after 3 months of traditional leaching. A series of technological improvements, which included of antiscalant addition, ore washing, classified crushing and screening, thin-layer conveying and dumping, and mechanical/chemical activation, were applied in YCM to enhance heap permeability and copper extraction from low-grade copper oxides. These improvements increased copper extraction to over 60 and the production of cathode copper reached 2500 t/a. Related topics such as: ore surface erosion, particle size distribution, heap structure, irrigation rate, and passivation and its effects are also discussed in this study. Even though some of the relevant mechanisms for enhanced recovery are still being studied, this successful industrial case provides a good reference for copper oxide mines encountering similar problems.