Spatial and in-product density characterization of in-use copper stocks in Japan for stock recyclability assessment

•We characterized in-use copper stocks in Japan for stock recyclability assessment.•We introduced two indicators: spatial density (SD) and in-product density (PD).•Infrastructure-related products have large copper stocks and high PD but low SD.•Information and communication electronics exhibit high SD but low PD.•There is a trade-off between the amount of in-use copper stock, SD, and PD. In-use metal stocks comprise various products, and their recyclability is determined by several factors. Hence, a comprehensive characterization of in-use stocks is required for stock recyclability assessment. We characterized in-use copper stocks in Japan by introducing two indicators to represent stock attributes relevant to recyclability: spatial density (SD) and in-product density (PD). SD is based on the spatial distribution of in-use stock, which is estimated by material flow analysis. PD is quantified based on the disassembly tree and level concepts and input-output analysis framework. Infrastructure-related products exhibited a relatively weak correlation with population and low SD, suggesting relatively large efforts required for collection. In contrast, information and communication electronics exhibited higher SD but lower PD, suggesting relatively large efforts required for preprocessing and recovery stages. Furthermore, integrated density characterization demonstrated a trade-off between three aspects related to recyclability: the amount of in-use copper stock, SD, and PD.