Integration of Cyanidation and Roasting Methods for Complex Gold and Silver Ore with Semi-Refractory Behavior

Complex and semi-refractory gold–silver ores pose significant challenges for efficient metal recovery using conventional cyanidation methods. This study investigates the effect of roasting thermal pretreatment on the leaching performance and mineralogical structure of a polymetallic gold–silver ore from northeastern Türkiye. The samples were roasted at 220 °C, 420 °C, and 620 °C prior to cyanidation to evaluate roasting-induced mineralogical transformations and their effects on metal recovery. High-temperature roasting markedly improved both gold and silver recovery. Gold recovery increased from 75% for the untreated ore to 95.84%, while silver recovery increased from 69.72% to 86.12% after roasting at 620 °C. XRD analysis indicated the transformation of pyrite to hematite, while the characteristic reflections of kaolinite and sphalerite were no longer detected at 620 °C. Moreover, the lowest cyanide consumption (6.5 kg NaCN/t ore) was observed after roasting at 620 °C, coinciding with the highest Au and Ag recovery. These results indicate that roasting-induced mineralogical transformations enhance the accessibility of precious-metal-bearing phases during subsequent cyanidation. Overall, controlled high-temperature roasting shows potential for improving Au and Ag recovery while reducing cyanide consumption in complex semi-refractory ores.