Separation and enrichment of elemental sulfur and mercury from hydrometallurgical zinc residue using sodium sulfide
(1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,
Kunming 650093, China;
2. National Local Joint Engineering Laboratory of Engineering Applications of Microwave Energy and
Equipment Technology, Kunming University of Science and Technology, Kunming 650093, China;
3. Key Laboratory of Unconventional Metallurgy of Ministry of Education,
Kunming University of Science and Technology, Kunming 650093, China)
Kunming 650093, China;
2. National Local Joint Engineering Laboratory of Engineering Applications of Microwave Energy and
Equipment Technology, Kunming University of Science and Technology, Kunming 650093, China;
3. Key Laboratory of Unconventional Metallurgy of Ministry of Education,
Kunming University of Science and Technology, Kunming 650093, China)
Abstract: The separation and enrichment of mercury and the recovery of elemental sulfur from flotation sulfur concentrate in zinc pressure leaching process were carried out by sodium sulfide leaching and carbon dioxide precipitating. The results show that the leaching rate of elemental sulfur is more than 98%, and 98.13% of mercury is enriched in the residue, under the optimized conditions of sodium sulfide concentration 1.5 mol/L, liquid/solid ratio 6:1 and leaching time 30 min at room temperature. In addition, the content of mercury is enriched 5.23 times that in the leaching residue. The elemental sulfur is precipitated from leaching solution under conditions of carbon dioxide flow rate 200 mL/min and blowing time 150 min, while solution is stirred adequately. The recovery efficiency of elemental sulfur reaches 97.67%, and the purity of elemental sulfur is 99.75%, meeting the requirements of industrial first-rate product standard according to the national standard of GB/T 2449-2006 (PRC).
Key words: flotation sulfur concentrate; sodium sulfide leaching; carbon dioxide precipitating; mercury enrichment; elemental sulfur recovery