稀土铝酸盐系三基色荧光粉废料中除Al新工艺

New Process of Aluminum Removal from Waste Rare Earth Aluminate Trichromatic Phosphors

针对稀土铝酸盐三基色荧光粉废料经碱熔、酸浸后所得稀土溶液中Al含量高的情况,提出了一种有机酸钠盐或钾盐选择性沉淀除Al的方法,考察了pH值、原始Al离子浓度、温度、选择性沉淀剂加入量等实验条件对除Al效果的影响。结果表明:控制选择性沉淀前稀土溶液pH值大于2.8,于常温常压下加入理论量1.3倍以上的选择性沉淀剂,溶液中残余Al含量小于0.22g/L,Al去除率达到98.6%,REO损失率仅为0.83%。

The rare earth solution obtained by alkali fusion and acid leaching of waste rare earth aluminate trichromatic phosphors usually includes high content aluminum.Therefore,sodium or potassium organic salt selective precipitation method was presented to purify the solution,and the effects were investigated of solution pH,initial aluminum content,temperature and selective precipitant dosage on aluminum removal.Experimental results show that under the conditions of initial rare earth solution pH higher than 2.8,room temperature and atmospheric pressure and precipitant dosage more than 1.3times the theoretical amount,the concentration of residual aluminum in the solution is less than 0.22g/L,aluminum removal efficiency reaches 98.6%,and rare earth loss rate is only 0.83%.