Separating and recovering Pb from copper-rich particles of crushed waste printed circuit boards by evaporation and condensation.
Separating and recovering Pb from copper-rich particles of crushed waste printed circuit boards by evaporation and condensation.
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DOI：
10.1021/es200243f
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发表时间：
2011-05
影响因子：
11.4
通讯作者：
Lu Zhan;Zhenming Xu
中科院分区：
文献类型：
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作者：
Lu Zhan;Zhenming Xu
采用破碎、静电分选的方法对废弃印刷电路板进行处理，得到富铜颗粒。但是，富铜颗粒中含有一定含量的焊料，如果处理不当，可能会造成Pb污染。本文研究了真空条件下铅从单一钎料和含铜钎料中的分离行为。由于富铜颗粒中Cu颗粒的存在，从混合颗粒中分离Pb比从单一焊料中分离Pb容易得多。在实验的基础上，总结了与以往研究不同的规律和现象，包括多层蒸发效应、Cu-Sn金属间化合物的形成等，并对这些现象的机理进行了探讨。在1123 K、0.1 ~ 1 Pa条件下，对WPCBs中的富铜颗粒进行分离回收。湿法多氯联苯中的铜、铅、锡等金属均得到有效回收。本研究丰富了蒸发冷凝法回收铅的分离规律，为回收废弃多氯联苯中有毒重金属提供了一种有效的方法。
Waste printed circuit boards (WPCBs) are treated by crushing and electrostatic separation to obtain the copper-rich particles. However, the copper-rich particles contain a certain content of solder, which may cause Pb contamination if improperly treated. The separation behaviors of Pb from single solder and solder mixed with Cu particles under vacuum are studied in this work. Due to the presence of Cu particles in the copper-rich particles, it becomes much easier to separate Pb from mixed particles than from single solder. On the basis of the experiments, the rules and phenomena different from previous studies are concluded, including the multilayer evaporation effect, the formation of Cu-Sn intermetallic compound and so on. Mechanisms of these phenomena are also explored. Pb is separated and recovered from copper-rich particles of crushed WPCBs at 1123 K for 90 min under 0.1-1 Pa. The metals including Cu, Pb, Sn in WPCBs are all efficiently recovered. This work enriches separating rules for recovering Pb by evaporation and condensation, and also points out an efficient and promising method for recovering toxic heavy metals from WPCBs.