Rapid gold cyanidation from a sulfur-high and arsenic-high micro-fine concentrate via facile two-stage roasting pre-treatment

This study was conducted on a micro-fine refractory gold concentrate with high levels of arsenic and sulfur, and main focus on being the roasting pre-treatment conditions and leaching conditions of the gold concentrate. Additionally, the potential reason and reaction mechanism of the roasting process were discussed, utilizing scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray powder diffraction (XRD), and X-ray fluorescence spectrometry (XRF). Satisfactory results were obtained when the gold concentrate was roasted for 2 h at 500 ???C followed by 3 h at 650 ???C. The reason responsible for rapid gold leaching from this type of ore lied in that the coating containing sulfur and arsenic around micro-fine gold particles was largely removed via roasting. Relatively lower cyanide consumption resulted from that (a) sulfur and arsenic in the ore were effectively removed with two-stage roasting and (b) the leach time required was extremely short. Notably, the good gold extraction of over 80 % and lower cyanide consumption of 0.82 kg/t were attained within only 0.5 h, and short leach time produced less inevitable ions content in the slurry, which is of great significance for subsequent purification processes and saving energy.