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Cradle-to-gate and efficiency studies of major materials used in electrical and electronic equipment

Final Report Summary - C2GE3E (Cradle-to-gate and efficiency studies of major materials used in electrical and electronic equipment)

The electrical and electronic equipment (EEE) sector is one of the biggest industries worldwide. In the EU, its employs over 4.3 Million people, and has a value added of more than 220 Billion € (European Commission. Functioning of the market for electric and electronic consumer goods. February 2012). Although information and communication technologies are perceived as low material and energy intensive sector due to the miniaturization of equipment, several studies pinpoint that it is false. For instance, a 2 g microchip requires 630 times its mass of fossil fuel and chemical inputs (Williams E, Heller M, Ayres RU. The 1.7 kg Microchip: Energy and Material Use in the Production of Semiconductor Devices. Environmental Science & Technology. 2003; 36(24): 5504-10). As result, in order to minimise the environmental impact of EEE, it is critical to optimise the amount of material and energy inputs during their life cycle that means reducing their resource use and improving their efficiency. The project “Cradle-to-Gate and Efficiency studies of the major materials used in Electrical and Electronic Equipment (C2GE3E)” had as an objective to study the life cycle of the plastics and metals used by EEE, with special attention to materials whose resource availability is unknown, and calculate the efficiency of those processes. The two initial tasks of objective 1, developed in parallel, were: an in-depth discussion about the need to quantify efficiency using exergy, as exergy helps identify better the potential improvements of processes, and the analysis of the production of plastics and metals used in greater amounts in EEE. The resource use and efficiency of materials used by EEE were defined following the second law of thermodynamics, hence using the concept of exergy. Exergy is defined as the fraction of the quantity of energy that can be converted to useful work. Thus exergy efficiency is calculated as the ratio of the potential useful (exergy) output, embodied in products and by-products, to the potential useful (exergy) input. Paper 1 (and also participation 3) discusses the appropriateness of using exergy and shows that the efficiency for US industry and economy are 37.6% and 7.7% respectively, well below the 80% and 42.5% values published by the U.S. Department of Energy in 2008, which denotes that there is a great potential for improvement. Participation 2 performs mass balances and exergy analyses of the production of more than 60 industrial chemicals all used during the production of plastics for EEE. The results were used later in paper 5 to estimate the exergy efficiency of the process chains of the plastics: acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polystyrene (PS), polyethylene (PE), polycarbonate (PC) polyvinyl chloride (PVC) and polyethylene terephthalate (PET). In overall, efficiencies can improve from 4% to 30% when processes are not isolated, but integrated as part of a multi-product process chain. The efficiency of the production chains of metals also varies greatly when processes are considered in isolation or integration. For instance, the efficiency of copper production increases by 22% when exergy losses from sulphide copper ore concentration and sulphuric acid production are recovered and used within the chain. The project also aimed evaluating the efficiency of scarce metals which refers to metals with average concentrations in Earth crust below 0.01% w/w (Skinner, B. J. In Earth resources, National Academy of Sciences of the US, 1979; pp. 4212-4217). During the literature survey, we learnt that most scarce metals occur in disperse ores as “contaminants”, or “hitch-hikers” of other metals, regarded as “attractors” like copper, nickel, aluminum, and iron ores. Thus before performing a mass balance of their production, we decided to study the dependence of these metals on mineral ores and “attractors”, a timeless research in line with several reports about critical metals (European Commission. Critical Raw Materials for the EU, 2010; US Department of Energy. Critical Materials Strategy, 2011; Buchert et al. Recycling critical raw materials from waste electronic equipment, 2012). Paper 2 (and also participation 4) shows the MFA of the “hitch-hikers”: cobalt, gallium, germanium, indium, niobium, molybdenum, rhenium, selenium, tantalum, and tellurium plus the platinum group metals (PGMs) and rare earth elements (REE) groups. The analysis provides insight on the limitations and potential of the future supply from primary sources, and end-products that contain these metals. In fact, we discussed (in paper 3) that the historical approach to increment supply by increasing exploration and open new mines is not applicable for “hitch-hikers”. Thus the future supply and production of “hitch-hikers” will depend partly on increasing the recovery rate from ‘attractor’ metals, improving extraction efficiencies and enhancing recycling. It also states that we cannot fully rely on recycling as most of these scarce metals end up in tiny amounts in devices too small to collect. The results urge product designers to think more carefully about how to minimize the losses of scarce metals during production, get them back in the system and to develop alternative technologies that avoid their use. Paper 4 gives an example about how the material and energy requirement, and losses during the extraction of a metal can be estimated theoretically. The paper provides a first estimate for the production of rare earths (RE) from diverse mineral ores which serve calculate the efficiency of their production. The results show that the greatest loss of RE occurs during the mining (25-50%) and the beneficiation (10-30%) of minerals. Identifying the properties of each metals allows understanding better their functions, and as result their end-uses. Paper 5 illustrates a possible way to explore the metabolism of each metal by using lithium as an example. The results show that its production from brines is more efficient than that from spodumene, and that recycling will become crucial to ensure its long-term viability as its demand for batteries in electric vehicles increases from 30% to almost 60% by 2020.
The objective 2 of the C2GE3E project was to study the material and energy flows during the lifespan of a multifunctional mobile phone and estimate the efficiency of its life cycle, using the results from objective 1 published in paper 6. The total exergy required for 100 grams mobile phone is about 136 MJ, almost 90% is used for the phone assembly as shown in participation 1. The efficiencies of the materials used are 23-40%, and the efficiency of mobile phone is likely to be similar to that of a semiconductor (10-3 to 10-4) if all the inputs for the component manufacturing and assembly are accounted (Branham, M.S. and T.G. Gutowski, Deconstructing Energy Use in Microelectronics Manufacturing: An Experimental Case Study of a MEMS Fabrication Facility. Environmental Science & Technology, 2010. 44(11): p. 4295-4301.). Such low efficiency is due to the high amount of energy required for all supporting process operation that is not recapture in other parts of the process leading to great exergy losses.
The results obtained in the C2GE3E project aim to aid life cycle analysis, resource accounting, and other industrial ecology tools used to quantify the environmental consequences of end-products using the plastics and metals studied. The results call for attention especially to EEE manufacturers and other sectors using scarce metals, and also to the EU that as a resource importing region should define measures to overcome possible supply restrictions and enhance recycling. Future supply restriction may occur, as already happened with rare earths, as China produces more than 60% of metals in the world but also consumes nearly 70% of the total output (Lifton, J. The future markets for the rare technology metals in Technology Metals Research, July 16 2013). In the light of this situation, recycling will play a major role in the future. Metal recycling companies should concentrate in developing processes that allow recover the tiny amount of metals embodied in products as mobile phones, laptops, flat screen displays, etc. Building up a stronger metal recycling sector requires the creation of interdisciplinary work teams with depth-knowledge on metallurgical engineering in order to explore possible ways to improve current recovery rates, EEE manufacturers to provide more detailed information about the amount and composition of these products, and waste collectors to define better strategies to raise the amount of collected end-of-life products. Public concern about the environmental impacts generated by EEE is also crucial to favour the collection, recycling and reusing against housekeeping and inappropriate waste management. However we should not underestimate the great potential to improve current efficiencies by integrating processes and improvements in technologies as they are still the first step in the whole supply chain.