铋精矿加压氧化氨浸高效分离铜、硫和铋

针对湖南柿竹园铋精矿火法冶炼过程中存在的成本高、低浓度SO₂和散烟排放污染环境、有价金属综合回收率低等问题, 以柿竹园铋精矿为原料, 提出了加压氧化氨浸分离铋与铜、硫的新工艺, 研究了氨水加入量、浸出温度、浸出时间、浸出压力及浸出液固比等因素对铜、硫、铋浸出率的影响。在氨水用量1.8 mL/g_铋精矿、液固比4∶1、釜压2.8 MPa、浸出温度160 ℃、浸出时间5 h、搅拌速度600 r/min的优化工艺条件下, 铜、硫浸出率分别达93.57%和92.87%, 铋不浸出并以氧化铋形态全部入渣, 实现了铜、硫与铋的高效分离。

Efficient Separation of Copper,Sulfur and Bismuth by Ammonia Pressure Leaching of Bismuth Concentrate

Problems of high cost, environment pollution caused by low concentration of SO₂ and smoke emissions, and low comprehensive recovery rate of valuable metals have been found during the pyrometallurgical processing of bismuth concentrate in Hunan Shizhuyuan Nonferrous Metals Company. Consequently, a new processing technique of ammonia pressure leach was proposed for separating bismuth from copper and sulfur, with the bismuth concentrate from Shizhuyuan Company as the raw material. Effects of factors, including the amount of ammonia water, leaching temperature, leaching time, pressure and liquid-solid ratio, on the leaching rates of copper, sulfur and bismuth were investigated. It is shown that leaching rates of copper and sulfur can reach 93.57% and 92.87% respectively, with an addition of ammonia water at an amount of 1.8 mL/g, liquid-solid ratio at 4∶1, autoclave pressure at 2.8 MPa, leaching temperature of 160 ℃, leaching time of 5 h and stirring speed of 600 r/min. It is found that bismuth is not leached out, but completely pulled into slag in the form of bismuth oxide, which indicates an efficient separation of copper, sulfur and bismuth is attained.