Contributions of extended batch tests for assessing technical recyclability: A case study of low‐value battery flows

Abstract

Good product recyclability is a prerequisite for the transition to a circular economy.However, today's product complexity and diversity in the urban mine result in heterogeneous and variable waste flows affecting process recycling efficiency (RE) and thus product recyclability. For batteries, waste flow composition and subsequent RE are determined by usage behavior, collection, and sorting into chemical battery subsystems. This study aims to demonstrate how extended batch tests (EBTs) can be used as a method to (a) determine battery-specific RE and (b) derive recommendations for assessing and improving the recyclability of batteries. Three EBTs comprising extensive characterization methods were carried out with mixtures of zinc-based (AZ) and lithium-based (LIB) batteries. The results showed that 0.20-0.27 kg/kg of the input mass was lost through flue gas and not recyclable. The metal fraction (0.15-0.19 kg/kg) was easily recyclable, while the mineral fractions of LIBs posed challenges for recycling and recovery (RR) due to the high elemental heterogeneity and pollutants originating from individual battery subsystems. In total, 0.79 kg/kg of AZs was recyclable, whereas 0.52 kg/kg of LIBs and 0.58 kg/kg of AZLIBs (a mixture of both) were recyclable after further treatment. In conclusion, the study demonstrated how the EBT approach can be used to extend recyclability assessment by providing waste flow characteristics for comparison with output quality requirements, enabling assignment of battery-specific RE and identification of poorly recyclable battery subsystems. Thus, the EBT approach can help improve and assess technical recyclability in the future.