Refining and Utilization of Rare Earth Elements from Phosphors in Waste Fluorescent Lamp

为建立荧光灯废弃物中稀土组分的回收体系，研究了荧光粉泥的分离和酸浸行为。首先，采用重介、水力、气流、重选和浮选等方法研究了磷泥中稀土组分和磷酸钙的分离特性。新开发的重介质分选方法的稀土荧光粉的分选效率、回收率和品位最高，气流分选次之。磷渣经气流分选后，在不同的酸性溶液和氢氧化钠溶液中浸出稀土组分。为了回收浸出液中的可溶性组分，采用氢氧化物沉淀和草酸盐沉淀等处理工艺回收稀土组分。采用三种工艺从荧光灯废荧光粉渣中有效回收钇和铕 ...更多信息 包括气流分离法、硫酸浸出法和草酸盐沉淀法。最终回收率约为65%，纯度为98.2%。研究了以废荧光灯处理后的荧光粉渣为原料合成Y_2O_3：Eu^<3+>的合成方法和烧结条件，确定了以废荧光灯处理后的荧光粉渣为原料合成Y_2O_3：Eu^<3+>的方法。Y_20_3：采用1.5mol/L硫酸浸取、氢氧化物沉淀、草酸盐沉淀、冷冻干燥、最佳烧结条件制备Eu^3+，烧结温度为1200℃，烧结时间为40 h，添加1%的硼酸钡作助熔剂。Y_20_3：以磷渣为原料合成的Eu^<3+>粉体具有良好的晶体结构，粒径在0.2 μm以上，且50%的粒径在5-6 μm之间。结果表明，以荧光粉渣为原料合成的Y_2O_3：Eu^<3+>粉末可以作为稀土红色荧光粉使用。少

The separation and acidic leaching behaviors of phosphor sludge have been examined to establish the recycling system of rare earth components contained in fluorescent lamp waste. At first, separation characteristic of rare earth components and calcium phosphate in phosphor sludge was investigated by heavy media separation, hydro separation, pneumatic separation, gravity separation and flotation. Newly developed heavy media separation method showed highest separation efficiency, recovery and grade of rare earth phosphors and the pneumatic separation was the second result. After pneumatic separation of phosphor sludge, rare earth components were leached in various acidic solutions and sodium hydroxide solution. For recovery of soluble component in leaching solution, rare earth component was recovered by treatment processes such as hydroxide and oxalate precipitations. Yttrium and europium from phosphor sludge contained in fluorescent lamp waste were recovered effectively by three process … More es of pneumatic separation, sulfuric acid leaching and oxalate precipitation methods. Their recovery was finallv about 65%, and its purity was 98.2%. It was also found that separation and recovery of rare earth elements from the leaching solution by multistage countercurrent extraction were possible.Synthesis method and sintering conditions have been examined to establish the synthesizing Y_20_3 : Eu^<3+> from phosphor sludge in processing waste fluorescent lamp. Y_20_3 : Eu^<3+> were synthesized by 1.5 mol/l sulfuric acid leaching, subsequent treatment processes such as hydroxide and oxalate precipitations, freeze-dry, and sintering in optimum condltions ; sintering temperature is 1200℃, sintering time is 40 hours, with addition of 1% barium borate as the flux. Y_20_3 : Eu^<3+> powder synthesized from phosphor sludge, was obtained well crystal structure of above 0.2 μm crystal size, and with 50% particle size in the range of 5-6 μm. It was found that Y_20_3 : Eu^<3+> powder synthesized from phosphor sludge by this work could be used substantially as a red rare earth phosphor. Less