Implementation and practice of an integrated process to recover copper from low grade ore at Zijinshan mine

Abstract

It is a challenge to recover copper from low grade ore in an environmentally sustainable way, especially from low-grade copper sulfide resources. This paper introduces Zijinshan Mine where an integrated process was developed and applied to recover copper from low-grade copper sulfide ore and acid mine drainage (AMD). The process includes the main operations of milling-flotation, heap bioleaching, solvent extraction-electrowinning (HBL-SX-EW) and copper precipitation. Ore with a grade higher than 0.25% Cu is fed to milling-flotation plant to produce copper concentrates, while the ore with grade lower than 0.25% Cu is sent to HBL-SX-EW to produce copper cathode via SX-EW. Because the copper resource consists mainly of secondary copper sulfides with high pyrite, and the mine is located in a region of high rainfall, a large volume of acid mine drainage is generated. In order to protect the environment, recover copper and make acid and iron balance, the acid mine drainage is respectively distributed to heap bioleaching, SX and sulfide precipitation, depending on the copper concentration of the wastewater. The paper also introduces the progress of tailings utilization, environmental protection and mine ecological restoration at Zijinshan mine.