氨-碳酸盐法分离PTA废渣中的钴和锰

Study on separation of cobalt and manganese from waste residue of PTA by ammonia-carbonate leaching

精对苯二甲酸(PTA)生产中的废钴锰催化剂中钴低锰高,常用的钴锰分离方法一般不适用,分离钴锰时非常容易互相夹带,导致分离不完全。本文采用氨-碳酸盐法分离PTA废渣浸出液中的钴和锰。在正交试验的基础上,以钴剩余率和锰沉淀率作为考核指标,考察了碳酸盐的种类、反应时间、反应温度、搅拌速度、氨的用量和碳酸盐的用量等因素对钴、锰分离效果的影响。实验结果表明,在氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中,最佳搅拌速度、反应时间、反应温度分别为200r/min、8h和20℃,氨的最佳用量分别为理论化学反应计量的1.9倍、1.4倍和1.7倍,碳酸盐的用量分别为理论化学反应计量的1.0倍、1.3倍和1.3倍。在最佳反应条件下,氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中,钴的最大剩余率分别可达到96.0%、99.8%和99.5%,锰沉淀率均可达到100%。

The content of cobalt in the waste cobalt and manganese catalyst in the production of PTA was low and the content of manganese was high. The common cobalt and manganese separation methods generally were not suitable for this material and would make cobalt and manganese mixed with each other,leading to incomplete separation. Ammonia - carbonate method was used in the separation of the cobalt and manganese from lixivium of the waste residue of PTA in this paper. As the surplus rate of cobalt and the precipitation rate of manganese were used as assessment indicators,the effects of the carbonates’ types,reaction time, temperature,stirring speed,the amount of ammonia and the amount of carbonate on the separation effect of cobalt and manganese were studied on the basis of orthogonal experiments. Experimental results show that,in the solutions of ammonia-sodium carbonate,ammonium carbonate and ammonium bicarbonate,the best reaction condition is： stirring rate 200r/min,reaction time 8 hours and temperature 20℃. The amount of ammonia is 1.9,1.4 and 1.7 times of chemical stoichiometric coefficient, respectively, and the amount of carbonate is 1.0,1.3 and 1.3 times. The surplus rate of cobalt in these three solutions can reach to 96.0%,99.8% and 99.5%,respectively,and the precipitation rate of manganese can all reach 100%.