A Review on the Research of Hydrometallurgical Leaching of Low-Grade Complex Chalcopyrite

Chalcopyrite is the main mineral source of copper ore for extracting and producing copper. However, with the continuous mining of copper ore, the grade of chalcopyrite decreases year by year and its composition becomes more and more complex. The traditional pyrometallurgical extraction process has been unable to make efficient use of such resources, and it is extremely urgent to explore an efficient and environmentally friendly hydrometallurgical leaching method of chalcopyrite. In this paper, the research progress of hydrometallurgical leaching of low-grade complex chalcopyrite is reviewed, and the advantages and disadvantages of mainstream leaching processes such as oxidation leaching, coordination leaching, and biological leaching are analyzed. The analysis shows that bioleaching is suitable for the leaching copper from low-grade chalcopyrite and even original ore, but the leaching rate is not high, and the time for bacterial culture and domestication, as well as the leaching cycle is long. The time of the oxidation leaching is short, the reaction conditions are mild, but the oxidant is difficult to recycle resulting large consumption. Coordination leaching is highly selective, but the system is highly corrosive and requires high investigation in equipment. No matter what kind of process is adopted, the passivation layer composed of elemental sulfur, polysulfide, and jarosite will be produced in the process, hindering the leaching. Increasing the research on the adaptability and selectivity of microorganisms is the direction of bioleaching, and the selective leaching in coordination leaching under ammonia medium with the synergy of oxidant and coordination agent can be realized. In addition, the formation of passivated layer can be inhibited by controlling acidity and redox potential, and the passivated layer can be stripped or eroded by microwave or ultrasonic reinforcement, so as to improve the efficiency of leaching reaction.Graphical Abstract