Multi-tool methodology to evaluate action levers to close the loop on critical materials – Application to precious metals used in catalytic converters

Abstract

Implementing circular economy (CE) practices can lead to both environmental savings and competitive advantages for companies. While transitioning from a linear production system to a closed-loop system is not straightforward, adequate methodology and tools can support industrialists in this sustainable shift. This paper proposes a multi-tool approach to systematically identify, classify, and assess the contribution of influence parameters and action levers to close the loop on products and key materials. Industrial ecology and model-based engineering tools are combined to ensure a systemic analysis and evaluation. The developed multi-tool approach combines, in a stepwise methodology, material flow analysis, fuzzy cognitive mapping, structural analysis, and system dynamics, to model and qualify the impact of potential and promising CE strategies. To illustrate each step of this multi-tool methodology, a case study is carried out on a real-world industrial product: a catalytic converter, which contains a non-negligible amount of platinum, considered as a critical raw material by the European Commission. New insights to close the loop on platinum from catalytic converters are thus provided and discussed. Notably, the connections between key action levers to close the loop on platinum are identified and highlighted, including regulations to limit the number of exports, mandatory recycling and reuse rate, end-users behaviors, based on regulatory constraints and financial motivations, and platinum price fluctuation. These findings could help to generate and fine-tune an ad hoc system dynamics model to evaluate the impact of key action levers through more specific scenarios. For instance, the broader implication of this multi-tool methodology could support an original equipment manufacturer in the evaluation of potential CE strategies, through the simulation of selected action levers on the circularity and sustainability performance of their value chain. Ultimately, it could provide quantitative insights to relevant prospective questions, such as, what if a take-back scheme is proposed to augment the collection rate by a given percentage, or what if the design is modified for easy disassembly.