Department of Industrial Engineering and Information and Economy, University of L'Aquila, via Giovanni Gronchi n.18, Nucleo Ind.le di Pile, 67100 L'Aquila, Italy.
Waste Manag. 2013 Nov;33(11):2390-6. doi: 10.1016/j.wasman.2013.06.002. Epub 2013 Jul 3.
In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary to purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes.
本文描述了从荧光灯粉和阴极射线管（CRT）中回收钇的方法。处理这些材料的过程包括以下步骤：（a）酸浸，（b）用氢氧化钠和硫化钠净化浸出液，（c）用草酸沉淀钇，（d）草酸盐煅烧生产氧化钇。实验结果表明，净化溶液和回收钇所需的工艺条件强烈依赖于浸出液的组成，换句话说，取决于粉末是来自 CRT 的处理还是来自荧光灯。在最佳实验条件下，对于 CRT、荧光灯和 CRT/荧光灯混合（称为 MIX）粉末，氧化钇的回收率分别约为 95%、55%和 65%。在处理 MIX 和荧光灯粉末时，产率较低可能是由于除了其他金属外，仅从荧光灯粉末中共同沉淀了钇。通过改变 CRT 工艺的实验条件，可以将钇的损失降到最低。在任何情况下，来自 CRT、荧光灯和 MIX 的最终产品的纯度都大于 95%。此外，从工业角度来看，同时处理 CRT 和荧光灯粉末的可能性非常重要且有趣，因为有可能在一个工厂中处理来自两种不同电子废物的荧光粉。
