China Nonferrous Metallurgy

Feldspar, quartz, and calcite are representative gangue minerals in gold concentrates. During cyanide leaching, gold will partially adsorb onto the surface of the gangue minerals, resulting in gold loss. In this paper, the adsorption of gold on the surface of gangue under cyanidation conditions and its adsorption mechanism were studied. The results showed that the highest gold adsorption rate was achieved when the gangue dosage was added at 15g and the contact time was 20min, and the gold adsorption rates of feldspar, quartz and calcite were 14.80%, 3.70% and 2.48%, respectively. The experimental results were fitted using quasi-first order dynamics, quasi-second order dynamics, double constant model and Elovich model. The results showed that the adsorption of gold on the surfaces of the three gangue minerals all fitted the quasi-secondary kinetic model and the double constant model (R²＞0.96), indicating that the adsorption process was dominated by chemisorption and was more likely to occur. X-ray photoelectron spectroscopy (XPS) analysis showed that ≡Si—O^- on the surface of the gangue was the main gold adsorption site.