Extracting antimony from high arsenic and gold-containing stibnite ore using slurry electrolysis

This study investigated the leaching and electrowinning of antimony from a complex, high arsenic and gold containing stibnite concentrate ore (As-Au-Sb ore) using slurry electrolysis (SE). The results indicated that the leaching efficiency of antimony was higher than 98%, and those of iron and arsenic were about 5.50% and 1.14%, respectively. An energy consumption (Ah) of 1.1 times the 'benchmark' value, a duration of 6 h, temperature of 60 degrees C, 30 g/L HCl, 5 g/L Fe, 30 g/L antimony, and an anodic current density of 80 A/m(2) were found to be the optimal experimental conditions. The SE selectively leached antimony, while gold and arsenic were retained in the residue as a raw material for further gold extraction. The antimony content in the cathode antimony was > 98%, and arsenic content was less than or equal to 0.21%. The As-Au-Sb ore consisted of stibnite (Sb2S3), pyrite (FeS2), arsenopyrite (FeAsS), and quartz (SiO2), along with a small amount of muscovite (KAl2(AlSi3O10)(OH)(2)) and other gangue phases. Antimony mainly occurred in stibnite. During the SE, stibnite disappeared, leaving behind elemental sulfur. We proposed a comprehensive procedure for the separation and recovery of antimony from the As-Au-Sb ore. In this process, antimony was recovered in a single step in the form of cathode antimony (> 98%), thereby resolving the technical problem of antimony and arsenic separation and hence, preventing the contamination of plenty of arsenic soda slag and low-concentration SO2 that exists in the traditional pyrometallurgical process. The process was environmentally friendly and had advantages such as short flow and high resource utilization rate.