Verma Himanshu Ranjan, Singh Kamalesh K, Mankhand Tilak Raj
Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
Waste Manag. 2017 Feb;60:652-659. doi: 10.1016/j.wasman.2016.12.031. Epub 2016 Dec 29.
Present work reports the evaluation of dimethylacetamide (DMAc) as a solvent to dissolve the halogenated epoxy resin substrate (HERS) of waste printed circuit boards (WPCBs). Studies revealed that HERS dissolution attributes to the cracking and delamination of WPCB's layers. Variation of the parameters governing the dissolution elucidated that dissolution is directly dependent on temperature and WPCBs concentration in DMAc. The results also showed that increase in the WPCBs size drastically retards the rate of HERS dissolution. After delamination, the spent DMAc was regenerated, and the dissolved HERS was recovered as residue. The chemical structure of regenerated solution and recovered residue were found to be similar to pure DMAc and untreated HERS, respectively. Cyclic usage of regenerated DMAc revealed that 3-5% of DMAc is lost after each usage cycle while its effectiveness to dissolve the HERS remains equivalent to the pure DMAc. The dissolution of HERS ensures the liberation of copper cladded on the surface of WPCBs, and thus the proposed process avoids the requirement of highly energy intensive metal liberation processes.
目前的工作报道了对二甲基乙酰胺（DMAc）作为溶解废弃印刷电路板（WPCBs）卤化环氧树脂基板（HERS）的溶剂的评估。研究表明，HERS的溶解归因于WPCB各层的开裂和分层。对控制溶解的参数变化进行研究表明，溶解直接取决于温度和WPCBs在DMAc中的浓度。结果还表明，WPCBs尺寸的增加会极大地阻碍HERS的溶解速率。分层后，用过的DMAc被再生，溶解的HERS作为残渣被回收。发现再生溶液和回收残渣的化学结构分别与纯DMAc和未处理的HERS相似。再生DMAc的循环使用表明，每次使用循环后会损失3 - 5%的DMAc，但其溶解HERS的效果仍与纯DMAc相当。HERS的溶解确保了WPCBs表面覆铜的释放，因此所提出的工艺避免了对高能耗金属释放工艺的需求。
