Characterization and Gold Extraction of Gold-bearing Dust from Carbon-bearing Gold Concentrates

Gold-bearing dust generated during the roasting process of refractory gold concentrates is valuable as secondary gold resources. In this study, the characterization of gold-bearing dust from carbon-bearing gold concentrates was determined by direct cyanidation and mineralogy research. Moreover, identification of refractoriness in the dust was determined by selective removal of minerals. Results showed that the dust belonged to refractory ores. Gold was observed to be presented as native and electrum which main associated with iron oxides. After preleaching with a 6 mol/L NaOH solution, arsenic, and carbon removal rates were 99.66% and 60.63%, respectively, and gold extraction was 58.90%, only 4.60% higher than that of direct cyanidation. After preleaching with a 15 wt.% H2SO4 solution, iron, arsenic, and carbon removal rates were 33.65%, 80.38%, and 12.60%, respectively, and gold extraction achieved 80.40%. After roasting, carbon and arsenic removal rates were 95.00% and 54.65%, respectively, and gold extraction achieved 84.52% under the optimum condition. Removal of carbonaceous matter and iron oxides could efficiently improve gold extraction, and the adverse effects of carbonaceous matter and iron oxides were the main reasons for refractoriness. Based on these results, a proper process for gold extraction from the dust was developed, and gold extraction achieved 95.50%.