Qualitative and quantitative determination of heavy metals in waste cellular phones.

Environmental impacts and use of brominated flame retardants in electrical and electronic equipment

Electronic waste, or e-waste, is an emerging problem with the developed nations as with developing nations. In the absence of proper collection and disposal systems, awareness and proper regulations, the problem is rather more acute in developing nations. These wastes are environmentally hazardous on one hand and valuable on the other. They contain substantial amount of metal value including precious metals. Personal computers are the biggest contributors to e-waste followed closely by televisions and mobile phones. The growth in their consumption pattern indicates a manifold increase in the volume of e-waste and calls for immediate attention to the management of e-waste in general and their recycling and reuse in particular.

Their recovery, recycle and reuse have become mandatory. Research and development work on their recycling has led to several technological options. However, a close investigation of the options reveals that there is no universally acceptable model for management of e-waste and they are still evolving. The technology for recycling depends on the economic status of the region along with several other factors. R&D efforts towards management of e-waste and its recycling is seriously lacking in India.

There are three main constituents of e-waste, namely, glass, plastics and metals. The glass may be re-melted for production of glass or for recovery of lead. The thermosetting plastics are difficult to recycle. The other types of plastics can be recycled for use as fuels or production of chemicals. The metals may be separated from the plastics and processed for recovery of individual metals. It may be said that physical separation techniques followed by metallurgical treatment is the best proposition for recovery of metals. Detailed technology development needs to be taken up for the recycling of e-waste that may serve the interest of the region best.

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A Review of Technology of Metal Recovery from Electronic Waste

This paper presents a study that characterizes, formulates, and solves the reverse logistic recycling flow equilibrium (RLRFE) problem. The RLRFE problem is concerned with the recycling channel in which recyclable collectors, processors, landfills, and demand markets form a multi-tiered network to process the recycled material flows from sources destined either for landfills or demand markets. Motivated by a government policy making or enterprise conglomerate recycling system design and operation needs, the RLRFE problem is elaborated from a system-optimal perspective using the variational inequality (VI) approach. For each origin–destination (OD) pair, the corresponding equilibrium conditions are established as a variation of the Wardrop second principle. In light of demand and cost function interactions, a nested diagonalization solution (ND) algorithm is proposed that gradually transforms the RLRFE problem into a traffic assignment model. To address multiple landfills in the recycling network and to understand how a variable-demand problem can be analyzed as a fixed-demand problem, we propose a supernetwork representation of the RLRFE problem. A numerical analysis on a test case illustrates the model formulation and the proposed algorithm.

On the modeling and solution algorithm for the reverse logistics recycling flow equilibrium problem

Abstract This study assessed the progression of Pb, Cd and Cr concentrations in plastic components (PCs) and printed wiring boards (PWBs) of 59 end-of-life (EoL) mobile phones (MPs) produced between 2000 and 2015 by two leading original equipment manufacturers (OEMs) patronized by Nigerians. This was done to study the behavior of OEMs in complying with some widely acceptable regulations. Metals in PCs and PWBs of MPs were extracted following EPA 3050B method and extracts were analyzed using atomic absorption spectrophotometry technique. Furthermore, Toxicity Characteristic Leaching Procedure (TCLP) test was conducted on selected samples to assess metal leachability in landfill conditions. Summary of results (mg/kg) for PCs and PWBs for MPs produced by OEM 1 and OEM 2 in brackets ranged thus: PCs, Pb: 5.00 –195 (LOD-1750), Cr: LOD-6050 (LOD-2170) and Cd: LOD-1.00 (LOD-5.75) while PWBs, Pb:129-9750 (5.00-12125), Cr: LOD-5488 (LOD-4000) and Cd: LOD-1.00 (0.25-1.00). There were no regular trends for all metals for both OEMs. Results suggest that a greater percentage of MPs produced till 2015 contained Pb and Cr higher than RoHS and TTLC limits. Furthermore, 50% of TCLP extracts contain Pb higher than EPA limit of 5 mg/L. Therefore, EoL MPs arising in Nigeria should be handled as hazardous materials.

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Assessing the progression of metal concentrations in plastic components and printed wiring boards of end-of-life mobile cell phones

All the countries in the world have done enormous work on lawmaking, technical problems of recycling engineering, managerial problems of recycling and the building of recycling plants, which has played an active role in regulating and promoting the recycling of waste electrical and electronic equipment. However, our country is still studying such system in the phase of a trial run, without considering recycling and processing as an entire system. Although the processing plants have been introduced, a recycling system is urgently needed to be set up. This thesis has put forward three applicable basic models in dealing with the recycling waste electrical and electronic equipment in the base of extended producer responsibility.

Guohong Wang

Papers

A Research into the Recycling System of Waste Electrical and Electronic Equipment in China