含汞加压浸出锌渣浮选硫精矿中分离富集有价元素的工艺研究

Separation and enrichment of valuable elements from flotation sulfur concentrate by sodium sulfide leaching-carbon dioxide precipitating in pressure leaching zinc process

利用Na2S浸出-CO2沉淀法从浮选硫精矿中分离和富集有价金属汞和锌,并对元素硫的回收进行了研究。通过正交设计对影响浸出过程的Na2S浓度、液固比、浸出时间和温度等因素进行优化。研究结果表明,以浓度1. 5 mol/L Na2S溶液为浸出剂,在6∶1的液固比条件下常温浸出30 min,元素硫浸出率可达98%以上,同时有价金属锌和汞在浸出渣中的质量分数为原矿石的5倍以上,富集率高于98%。向浸出液中通入CO2气体,充分搅拌溶液,在CO2流量为200 m L/min、通气时间为150 min的条件下,元素硫从溶液中析出,回收率可达到97. 67%。

By using sodium sulfide leaching-carbon dioxide precipitating method,valuable metals including mercury and zinc are separated and enriched,and sulfur is recovered from flotation sulfur concentrate in pressure leaching zinc process.The optimization for influence factors such as sodium sulfide concentration,liquid/solid ratio,leaching time and temperature in the leaching process is made by orthogonal experiment design.It is indicated that more than 98%of elemental sulfur is leached out,higher than 98%of the average enrichment ratio for both mercury and zinc in the residue are realized under the optimal conditions that sodium sulfide concentration is 1.5 mol·L-1,liquid/solid ratio is 6∶1,and leaching time 30 min at room temperature.Both contents of mercury and zinc in leaching residue exceed 5 times that in raw ore.Sulfur precipitates from leaching solution after carbon dioxide flows at a rate of 200 m L·min-1 into leaching solution for 150 min.The recovery efficiency of elemental sulfur can reach 97.67%.