Institute of Chemical Process Engineering, University of Alicante, P.O. Box 99, E-03080, Alicante, Spain; Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080, Alicante, Spain.
Institute of Chemical Process Engineering, University of Alicante, P.O. Box 99, E-03080, Alicante, Spain; Department of Chemical Engineering, University of Alicante, P.O. Box 99, E-03080, Alicante, Spain.
J Environ Manage. 2022 Sep 1;317:115431. doi: 10.1016/j.jenvman.2022.115431. Epub 2022 May 29.
An effective management of waste printed circuit board (WCB) recycling presents significant advantages of an economic, social, and environmental nature. This is particularly the case when a suitable valorisation is made of the non-metallic parts of the WCBs, well known for their "hidden" toxicological risks. Such benefits motivate research on techniques that could contribute to mitigating their adverse socio-environmental impacts. In this work, waste printed circuit boards (WCBs) containing tetrabromobisphenol A (TBBPA) as a brominated flame retardant (BFR) underwent debromination using a mechanochemical treatment (MCT) and marble sludge, another recoverable waste, as well as pure CaO as additives. All runs in this work were performed at an intermediate rotation speed of 450 rpm, using additive/WCB mass ratios (R) of 4:1 and 8:1, ball to powder ratios (BPR) of 20:1 and 50:1, treatment times from 2.5 h to 10 h, two WCB sizes (powder and 0.84 mm) and marble sludge, from original to precalcined conditioning. Stainless steel jars and balls were used to verify the effect of each parameter on the system and to seek an optimum process. Complete debromination of 0.84 mm WCBs was achieved at 450 rpm, using a R of 8:1, a BPR of 50:1, a residence time of 10 h (more than 95% in only 5 h), and a precalcined marble sludge as additive. The results revealed that when using a R of 4:1 instead of 8:1, more waste could be effectively treated, per batch with a lesser need for additives, at the expense of a slightly lower level of debromination efficiency. In the same way, an appropriate apparent ball diameter (with respect to the volume of the used jar) should be carefully studied in relation to WCB size in order to achieve a beneficial total amount of energy transfer during milling.
有效管理废印刷电路板（WCB）回收具有重要的经济、社会和环境优势。当 WCB 的非金属部分得到适当的增值利用时，尤其如此，这些部分众所周知存在“隐藏”的毒理学风险。这些好处促使人们研究能够减轻其不利社会环境影响的技术。在这项工作中，含有四溴双酚 A（TBBPA）作为溴化阻燃剂（BFR）的废印刷电路板（WCB）通过机械化学处理（MCT）和另一种可回收废物大理石污泥以及纯氧化钙作为添加剂进行脱溴。在这项工作中的所有运行均在中间转速 450 rpm 下进行，使用添加剂/WCB 质量比（R）为 4:1 和 8:1，球对粉末比（BPR）为 20:1 和 50:1，处理时间从 2.5 小时到 10 小时，使用两种 WCB 尺寸（粉末和 0.84 毫米）和大理石污泥，从原始到预煅烧条件。使用不锈钢罐和球来验证每个参数对系统的影响，并寻求最佳工艺。在 450 rpm 下，使用 R 为 8:1、BPR 为 50:1、停留时间为 10 小时（仅 5 小时内超过 95%）和预煅烧的大理石污泥作为添加剂，可实现 0.84 毫米 WCB 的完全脱溴。结果表明，当使用 R 为 4:1 而不是 8:1 时，每批可以更有效地处理更多的废物，而添加剂的需求量更少，但脱溴效率略低。同样，应该仔细研究与 WCB 尺寸相关的适当表观球径（相对于使用罐的体积），以便在球磨过程中实现有益的总能量传递量。
