Feedstock Recycling Technologies in the Sustainable Recycling of Plastics from End-ofLife Electrical and Electronic Products

Abstract

This paper is the third in a series that examines critical factors in the sustainable recycling of plastics from end-of-life (EOL) electrical and electronic equipment (EEE). Previous papers provided an overview of the subject (Sustainable electrical and electronic plastics recycling, ISEE 2004) and the role of energy recovery (Energy recovery in the sustainable recycling of plastics from electrical and electronic products, ISEE 2005). The present paper draws from the earlier papers and explores the role of feedstock (chemical) recycling. In general, plastics recovery consists of two basic process types - material recovery and energy recovery. Two categories of material recovery are of principal interest, mechanical recycling and feedstock recycling. Mechanical recycling reprocesses post-use plastics to plastic recyclates (secondary plastic materials). Feedstock recycling, sometimes referred to as chemical recycling, is the process that converts plastics back to basic petrochemical feedstocks for use by industry in the form of syn crude, process chemicals, or fuels. Feedstock recycling can be broken down into pyrolytic liquefaction; gasification, including the case where the chemical content of the plastics becomes an integral part of an industrial process such as ferrous and non-ferrous metal smelting (reduction processes); hydrogenation processes; and chemical recycling back to reactive monomers or high value oligomers. Feedstock recycling of plastics, although still largely developmental, is being evaluated on a large scale in the United States, Europe, China, and Japan. The plastics industry is actively engaged in R&D. Feedstock recycling technologies can both recover valuable materials and manage substances of concern in an environmentally sound manner. Feedstock recycling technologies have the potential to significantly increase the sustainable recovery of plastics from EOL EEE beyond what can be achieved using mechanical recycling and energy recovery