面向经济回收的产品设计系统构成

面向回收的产品设计能够使废旧产品得到更好的回收和重用，优化拆卸序列的生成必须基于产品拆卸的经济性分析。论述了面向经济回收的产品设计系统的构成及相关的关键问题，分析了产品的零件材料回收价值与拆卸工艺，建立了零件材料合理回收的评估方法。     

Performance improvement potential of sensor embedded products in environmental supply chains

Environmental supply chain is a desirable alternative to traditional supply chain due to new and stricter environmental regulations by local governments and increasing consumer awareness towards environmental issues. The two most common types of environmental supply chains are reverse supply chains and closed-loop supply chains. In reverse or closed-loop supply chains, collected used products are subjected to one of four recovery options, viz., reuse, recycling, remanufacturing or disposal. Regardless of the chosen recovery option, all products are disassembled up to some level. However, there is a high level of uncertainty associated with the disassembly yield due to non-functional and/or missing components. Sensor embedded products (SEPs) is a viable approach to cope with this uncertainty since they involve sensors which can detect non-functional and/or missing components prior to disassembly. This study presents a quantitative assessment of the impact of SEPs on the various performance measures of a kanban-controlled disassembly line. First, separate design of experiments studies based on Orthogonal Arrays are carried out for conventional products and SEPs. Then, the results of paired t-tests comparing the two cases based on different performance measures are presented.     

Closed loop recycling of plastics containing Flame Retardants

Annually 2.7 million tonnes of plastics containing Flame Retardants (FRs) are globally discarded in Waste Electrical and Electronic Equipment (WEEE). Little is known on the feasibility of closing material loops for FR plastics. Therefore, series of experiments were set up to analyze the feasibility of separating plastics containing FRs from one specific product category, namely End-of-Life (EoL) Liquid Crystal Display (LCD) TVs. The characterization of the housings of this waste stream indicated a concentration of 18 wt% Bromine based (Br) FRs and 31 wt% Phosphor based (P) FRs, the remainder not containing FRs. With practical tests it was demonstrated that, after disassembly and plastic identification, the co-polymer poly-carbonate (PC)/acrylonitrile-butadiene-styrene (ABS) containing PFR can be recycled in a closed loop system. Based on the determined plastic density distributions and separation efficiencies of optical sorters, a purity of 82% was calculated for PFR PC/ABS separated from EoL LCD TVs after size-reduction (shredding). Performed miscibility tests indicated that for this fraction at least a factor 10 dilution with virgin material is required. In addition, higher waste volumes are required for a size-reduction based treatment to become economically viable and technical challenges still need to be faced, whereas closed loop recycling of PFR PC/ABS from the current waste stream of EoL LCD TVs of different brands in a disassembly based treatment is found to be technically feasible and economically viable under European boundary conditions.     

Waste electric and electronic toys: Management practices and characterisation

The main objective of this paper is to characterise, both physically and chemically, waste electric and electronic toys, belonging to the category 7 of the Directive, 2012/19/UE, in order to obtain information about the generation and composition of this waste which is not widely found in the literature. For this, a campaign was designed with the aim of collecting a representative sample of waste toys in different schools in a Spanish town. Altogether 1014.25 kg of waste toys were collected, of which 31.83% corresponded to the electric and electronic fraction, which is the object of study. The collected wastes were divided into subcategories and a representative sample of each was one used to characterise them physically and chemically. Physical characterisation provided information about the materials they were made of, the electrical and electronic parts, fixing and assembly systems, and so forth. The results showed that the weight of a toy is comprised of 72.30% of plastics, 12.07% of electrical and electronic components, 4.47% of metals, and 11.15% other materials. In general, the most common types of polymers were PS, PP and ABS. Chemical characterisation made it possible to analyse the composition of the plastic components, which is information that is essential to be able to determine the feasibility of recovering the resulting fractions. The results showed that the content of hazardous substances in these plastics is far below the limits stipulated in Directive 2002/95/EC (RoSH Directive). The findings of this study show a need for a specific management system for this fraction of domestic wastes and a wide range of potential reusability of the discarded toys since 65% of the toys from the collected sample worked in perfect condition. We also found that the end-of-life is one of the aspects that have not been considered during their design as both materials and disassembly sequence do not facilitate the end-of-life of this type of wastes. This information could be used to improve the ecodesign of electrical and electronic equipment toys regarding their end-of-life.