BRGM, 3 av. C. Guillemin, 45060 Orléans, France.
Waste Manag. 2013 Mar;33(3):706-13. doi: 10.1016/j.wasman.2012.04.007. Epub 2012 Jul 10.
Innovative separation and beneficiation techniques of various materials encountered in electrical and electronic equipment wastes (WEEE) is a major improvement for its recycling. Mechanical separation-oriented characterisation of WEEE was conducted in an attempt to evaluate the amenability of mechanical separation processes. Properties such as liberation degree of fractions (plastics, metals ferrous and non-ferrous), which are essential for mechanical separation, are analysed by means of a grain counting approach. Two different samples from different recycling industries were characterised in this work. The first sample is a heterogeneous material containing different types of plastics, metals (ferrous and non-ferrous), printed circuit board (PCB), rubber and wood. The second sample contains a mixture of mainly plastics. It is found for the first sample that all aluminium particles are free (100%) in all investigated size fractions. Between 92% and 95% of plastics are present as free particles; however, 67% in average of ferromagnetic particles are liberated. It can be observed that only 42% of ferromagnetic particles are free in the size fraction larger than 20mm. Particle shapes were also quantified manually particle by particle. The results show that the particle shapes as a result of shredding, turn out to be heterogeneous, thereby complicating mechanical separation processes. In addition, the separability of various materials was ascertained by a sink-float analysis and eddy current separation. The second sample was separated by automatic sensor sorting in four different products: ABS, PC-ABS, PS and rest product. The fractions were characterised by using the methodology described in this paper. The results show that the grade and liberation degree of the plastic products ABS, PC-ABS and PS are close to 100%. Sink-float separation and infrared plastic identification equipment confirms the high plastic quality. On the basis of these findings, a global separation flow sheet is proposed to improve the plastic separation of WEEE.
电气和电子设备废物 (WEEE) 中各种材料的创新分离和选矿技术是其回收的重大改进。为了评估机械分离过程的适宜性，对 WEEE 进行了以机械分离为导向的特性分析。通过粒度计数方法分析了对机械分离至关重要的分数（塑料、黑色和有色金属）的离解度等特性。这项工作对来自不同回收行业的两种不同样品进行了表征。第一种样品是一种含有不同类型塑料、黑色和有色金属、印刷电路板 (PCB)、橡胶和木材的多相材料。第二种样品主要包含塑料混合物。对于第一种样品，发现所有铝颗粒在所有研究的粒径中均为自由颗粒（100%）。92%至 95%的塑料以自由颗粒存在；然而，平均有 67%的铁磁颗粒被释放。可以观察到，只有 42%的铁磁颗粒在大于 20mm 的粒径中是自由的。还通过手动逐个颗粒地对颗粒形状进行了量化。结果表明，由于切碎导致颗粒形状变得不均匀，从而使机械分离过程复杂化。此外，还通过沉浮分析和涡流分离来确定各种材料的可分离性。第二种样品通过自动传感器分拣分为四种不同的产品：ABS、PC-ABS、PS 和剩余产品。使用本文所述的方法对这些颗粒进行了特性分析。结果表明，ABS、PC-ABS 和 PS 塑料产品的等级和离解度接近 100%。沉浮分离和红外塑料识别设备证实了塑料的高质量。基于这些发现，提出了一个整体分离流程图，以改进 WEEE 中的塑料分离。
