Metallurgical recycling processes: Sustainability ratios and environmental performance assessment

摘要

Recycling is considered as core element of the sustainable development. In reality, however, due to the physical and chemical limits of current recycling technologies, material and quality losses occur that affect the efficiency of recycling. This paper aims to assess the environmental performance of metallurgical recycling, from both a donor and user-side perspective, by using the emergy evaluation combined with exergetic life cycle assessment (ELCA). The developed evaluation model is based on Ulgiati's proposition to erase the memory of the recovered material and to account only for the current recycling cycle. The use of an average transformity is proposed to measure the environmental performance of recycled materials. Contrary to classical transformities, it evaluates the material based on all previous processes that generated the material while avoiding the "double counting". Finally, three sustainability ratios have been defined to further assess the benefits and limits of consecutive metallurgical recycling processes: the resource efficiency ratio alpha, the performance ratio beta and the eco-design ratio chi. Their functions have been.described and clarified with provided examples. (C) 2015 Elsevier B.V. All rights reserved.