破碎-分选废弃电路板混合金属中铅的真空分离-气化机理与超细粉的制备

The pollutions induced by heavy metals during the treatment of waste circuit boards are attracting more and more attentions, especially the Pb pollution. This research takes the mixed metallic partilces obtained after crushing and separating of waste circuit boards as raw materials. Under the vacuum conditions, the ultra fine Pb particles are produced through evaporation and inert gas condensation.The interaction effects of the complex metal components exerting on the lead effective separation and evaporation are researched. The internal relationships bewteen the preparation of ultra fine lead particles and the condensation methods, atmospheres, temperature field distribution are obtained, respectively.The thermodynamic law and the dynamic process of the Pb vacuum evaporation-condensation and nucleation- preparation of ultra fine Pb particles from the mixed metallic partilces are analysed. The model of Pb vacuum separation-evaporation-ultra fine particles preparation from the multi-component system of mixed metallic partilces is built in this research. The mechanism of preparing ultra fine Pb particles from the mixed metallic partilces is revealed. Therefore, this research will provide the theoretical foundation for the high quality recycling of Pb from waste circuit boards and other e-wastes.

废弃电路板在回收处理过程中引起的重金属污染问题受到越来越多的关注，特别是铅污染。本研究以经破碎-分选后的废弃电路板混合金属为原料，在真空条件下，采用加热蒸发气化与惰性气体冷凝的方法制备超细铅粉。研究废弃电路板混合金属中复杂金属成分对铅高效分离气化的交互作用，分析铅的气化-冷凝成核-制备超细粉的热力学规律和动力学过程，揭示冷凝方式、气氛、温度场分布等与制取超细铅粉之间的内在关系，建立废弃电路板混合金属多组元体系中铅的真空分离-气化-制备超细粉模型，得出超细铅粉的制备机制，为实现废弃电路板等电子废弃物中重金属铅的高品质回收提供理论依据。

近年来，电子产品更新换代速度的加剧，导致大量电子废弃物产生。本项目以废弃电路板为研究对象，主要研究了电路板焊锡中的铅在真空热处理过程中的蒸发冷凝规律，进而研究了气相骤冷制备铅纳米粉。研究发现，电路板中含有多种易挥发金属，包括铅、锌、镉、铋等，之间存在相互作用，锌、镉蒸气压较高，先于铅蒸发，而铋与铅形成合金，不利于铅蒸发。对于铅、锌等含量高的金属富集体，可采用多段蒸发冷凝的方式，使得蒸气压不同的金属依次蒸发分离。当铅大量蒸发时，通入氮气骤冷制粉。研究表明，关键影响因素有气压、流速、冷凝温度、收集基底等，会对粉末的形貌产生较大影响。该项目对电路板中的铅制备超细铅粉、氧化铅粉进行了初步探索，为电路板以及其他含铅固废的无害化、高附加值资源化提供了理论依据。围绕该项目，发表标注该项目号的SCI论文共7篇，包括4篇一区论文，其中一篇发表在环境领域顶级期刊EST上，申请3项专利，授权一项。