Strengthening Gold Extraction from Carbonaceous Gold Ore Based on Decarburization by Two-Stage Fluidized Oxidation Roasting

Oxidation roasting is one of the most effective methods to remove carbonaceous matter from carbonaceous gold ore. However, the consolidation of calcine is a common problem caused by a large amount of heat release during the oxidation roasting of gold ore with high carbon and sulfur content. In this study, a two-stage fluidized oxidation roasting method was developed to strengthen gold extraction. Pre-roasting was performed in a low oxygen environment for the mild combustion of carbonaceous matter, and then the pre-roasted product was subjected to secondary roasting followed by leaching. The results show that reducing the carbon content in the ore by pre-roasting can effectively lower the peak temperature inside the material. After the second-stage roasting, many cracks and pores were formed in silicates and carbonates, thus increasing the distribution of exposed gold from 28.95% to 88.01%. Finally, the extraction of gold increased from 4.55% to 86.10%. Overall, this study provides references for an efficient strategy for gold recovery from carbonaceous gold ores.