Resource Utilization of Iron and Gold from Roasted Cyanide Tailings by the Sulfuric Acid Activation Decomposition Method

This study uses sulfuric acid activation-water leaching method to decompose and leach iron from roasted cyanide tailings, thereby creating favorable conditions for the further leaching of gold from the tailings. The leachate obtained from the decomposition of iron is purified and then prepared into liquid polyferric sulfate. The gold in the leaching residue after iron decomposition is leached using cyanidation. The results show that at 100°C, by activating cyanide tailings with concentrated sulfuric acid for 1 h at a volume-to-mass ratio of 0.7:1, the leaching rate of iron can reach 82.64%. With 4000 g/ton of sodium cyanide used on the leached residue, the gold leaching rate can reach 83.4%. After reduction with iron powder, the strongly acidic, high-iron-content solution uses Na₂S as a precipitating agent to remove arsenic and zinc through a two-stage precipitation process. The arsenic content in the solution can be reduced from 253 mg/L to 5.01 mg/L, and the zinc content can be reduced from 207 mg/L to 65.8 mg/L. This study not only realizes the high-value utilization of waste but also reduces the accumulation of waste through the treatment of roasting cyanide tailings, which has a good application prospect.