Gandon-Ros Gerard, Aracil Ignacio, Gomez-Rico María Francisca, Conesa Juan A
Institute of Chemical Process Engineering, University of Alicante, P.O. Box 99, Alicante E-03080, Spain.
Department of Chemical Engineering, University of Alicante, P.O. Box 99, Alicante E-03080, Spain.
ACS Omega. 2022 Jul 13;7(29):25422-25432. doi: 10.1021/acsomega.2c02368. eCollection 2022 Jul 26.
The great economic, social, and environmental interest that favors an effective management of the recycling of waste printed circuit boards (WCBs) encourages research on the improvement of processes capable of mitigating their harmful effects. In this work, the debromination of large WCBs was first performed through a hydrothermal process employing potassium carbonate as an additive. A total of 32 runs were carried out at 225 °C, various CO /Br anionic ratios of 1:1, 2:1, 4:1, and 6:1, treatment times from 30 to 360 min, proportion of submerged WCBs in the liquid of 100, 50, and 25% that corresponded with the use of three WCB sizes of 20 mm × 16.5 mm, 20 mm × 33 mm, and 80 mm × 33 mm, respectively, and solid/liquid ratios of 1:2 and 1:1 g/mL without other metallic catalysts. A debromination efficiency of 50 wt % was reached at only 225 °C (limited by mechanical reasons) and 360 min, using a CO /Br anionic ratio of 4:1 and a solid/liquid ratio of 1:2 for a large WCB with only 25% of its volume submerged in the liquid. This means conservation of water and energy compared to previous studies. A muffle furnace was used later to thermally treat a total of 101 debrominated samples, at constant temperature or following a temperature scaling program. An estimated decrease in resistance to rupture of glass fibers of only around 50% was accomplished by following a temperature scaling program up to 475 °C, obtaining clean glass fibers of large size. The simple techniques proposed to obtain reusable glass fibers from WCBs as large as the size of the reactor allows (as it might be in their original size) could significantly improve interest in the industry.
对废弃印刷电路板（WCBs）回收进行有效管理具有重大的经济、社会和环境意义，这促使人们开展研究，以改进能够减轻其有害影响的工艺。在这项工作中，首先通过水热法对大型WCBs进行脱溴处理，使用碳酸钾作为添加剂。在225°C下共进行了32次实验，CO/Br阴离子比分别为1:1、2:1、4:1和6:1，处理时间为30至360分钟，WCBs在液体中的浸没比例为100%、50%和25%，分别对应三种尺寸的WCBs，即20mm×16.5mm、20mm×33mm和80mm×33mm，固液比为1:2和1:1g/mL，且不使用其他金属催化剂。在仅225°C（受机械原因限制）和360分钟的条件下，对于体积仅25%浸没在液体中的大型WCBs，使用CO/Br阴离子比为4:1和固液比为1:2时，脱溴效率达到了50 wt%。这意味着与之前的研究相比，节约了水和能源。随后使用马弗炉对总共101个脱溴样品进行热处理，采用恒温或按照温度缩放程序进行。通过在高达475°C的温度缩放程序下处理，玻璃纤维的抗断裂性估计仅降低了约50%，从而获得了大尺寸的清洁玻璃纤维。所提出的从与反应器尺寸相同大的WCBs（可能是其原始尺寸）中获取可重复使用玻璃纤维的简单技术，可能会显著提高该行业的关注度。
