钼酸铵溶液中锌净化新工艺的研究

Study on the New Process of Zinc Purification from Ammonium Molybdate Solution

针对一种复杂低品位钼精矿焙烧氨浸得到的钼酸铵溶液中Zn含量高的问题,在传统工艺基础上采用"碳酸铵-氨水、硫化铵"两段净化新工艺对经硫化铵处理后的钼酸铵溶液进行处理,着重考察了试剂用量、pH值、反应温度、反应时间对Zn脱除率的影响,得到优化净化工艺条件:一段净化中,碳酸铵加入量为理论量的1.2倍,反应温度45℃,反应时间0.5h,pH=9,Zn脱除率达95%以上;二段净化中,氨水和硫化铵加入量为理论量的1.1倍,反应温度45℃,反应时间0.5h,pH=8.5,Zn脱除率高于96%。综合Zn脱除率达到99.5%以上,Mo损失低于1%,净化液可直接通过酸沉、结晶获取钼酸铵一级品。

To solve the problem of high-zinc concentration in the ammonium molybdate solution obtained by roasting and ammonium leaching of a complex low grade molybdenum concentrate,a new two-stage purification process with ammonium carbonate-ammonia and ammonium sulfide was applied for the treatment of ammonium molybdate solution pretreated with ammonium sulfide.The effects were emphatically investigated of reagent dosage,pH value,reaction temperature and reaction time on zinc removal rate.The optimal conditions of purification process are obtained as follows：in the primary purification,ammonium carbonate dosage is 1.2 times of the theoretical amount with reaction temperature of 45℃,reaction time of 0.5 hand pH value of 9,and zinc removal rate over 95%.In the secondary purification,ammonia and ammonium sulfide addition is 1.1 times of the theoretical amount with reaction temperature of 45 ℃ and reaction time of0.5h,pH value of 8.5,zinc removal rate above 96%.The comprehensive removal rate of zinc is beyond 99.5%,and molybdenum loss rate is less than 1%.The purified solution can be directly treated through acid precipitation and crystallization to obtain ammonium molybdate product of the first grade.