A circular economy requires cross sector cooperation and optimization of a variety of processes and products from a holistic perspective. Due to the continuously increasing complexity of products and the rapid development of new sorting and recycling processes there is a continuous need to determine the optimal combination of existing and recently developed sorting and recycling processes for both well-known and recently emerging waste streams, such as LCD TVs, tablets and PV panels. The research group Life Cycle Engineering of the Mechanical Engineering Department of the KU Leuven has built up significant experience with the optimization of the recycling of Waste Electric and Electronic Equipment (WEEE) and End-of-Life Vehicles (ELVs) in close cooperation with several industrial partners. Within the European Horizon 2020 “PolyCe” project (2017-2021) it is the objective to apply this knowledge to plastic sorting and recycling in close cooperation with the technology campus Diepenbeek of the KU Leuven, that is focusing on polymer processing. It is the ambition of the research group to expand their research activities and to develop new optimization models and processes to better close plastic material loops in close cooperation with both original equipment manufacturers and recycling companies to accelerate the transition to a circular economy.