中国有色冶金

As a by-product from vacuum distillation of crude selenium, distilled selenium slag is enriched in copper, lead, selenium, tellurium, gold, silver, platinum, palladium and other valuable metals and is an important resource for precious metals recovery. The high content of selenium and tellurium, as well as their presence in multiple phase structures, and the formation of intercalation and inclusions with copper, gold and silver have limited the selective removal of copper, lead, selenium, tellurium, etc. from the slag. To achieve subsequent enrichment of precious metals, the process flow of “two-stage oxidation roasting-atmospheric alkaline leaching and nitric acid leaching” was proposed to treat the slag, in which, the primary oxidation roasting-atmospheric leaching can completely leach tellurium out, the secondary oxidation roasting-atmospheric leaching can realize selenium removal, the nitric acid leaching can remove copper and lead. After the three simple steps, the removal rate of selenium, tellurium, copper and lead can reach 92.72%, 95.84%, 95.43%, 99.57%, resp. The process has provided a feasible way for separating precious metals from base metals in distilled selenium slag.