Mechanical activation modes of chalcopyrite concentrate and relationship between microstructure and leaching efficiency

In this study, a high-energy planetary mill was used to perform mechanical activation of chalcopyrite in dry-, moist-, and wet-milling modes. Granulometric and microstructural changes of chalcopyrite were characterized, and their effects on Cu dissolution were distinguished. Although water was added during milling to reduce agglomeration, it led to the inhibition of energy transmission. The maximum Bmnauer-Emmett-Teller surface area of 8.382 m(2)/g was obtained in samples subjected to 7 h of moist milling. Dry milling resulted in considerable microstructural changes; the amorphization degree, grain size, and lattice strain of the chalcopyrite were 66.4%, 10 nm, and 0.427 x 10(-2), respectively. Samples that had undergone 7 h of dry milling exhibited the highest copper extraction efficiency of 48.9%, which was 81.5 times higher than that for the nonactivated samples. The results of kinetics analysis revealed that the degree of amorphization exhibited a greater reactivity of chalcopyrite than the surface area did, and the enhancement in the leaching efficiency was highly consistent with the mechanical activation parameter. In addition, because of the selective rupturing of the chalcopyrite lattice, a sulfur channel appeared on the surface of the dry- and moist-milling samples, which proved that passivation decreased and leaching was enhanced. The results of this study can provide considerable insight on chalcopyrite leaching.

Automated summary

This study used a high-energy planetary mill to mechanically activate chalcopyrite in different modes. Wet-milling resulted in higher BET surface area, while dry milling significantly affected the microstructural changes of chalcopyrite. Samples subjected to dry milling showed the highest copper extraction efficiency. The results suggest that mechanical activation parameters play a crucial role in enhancing leaching efficiency of chalcopyrite.