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Abstract
How to meet the unprecedented metal needs is one of the grand challenges worldwide. The previous emphasis has long been placed on extracting raw materials to satisfy such massive and diverse demand, with little attention paid to the sustainability of this pattern. Given resources become scarcer and harder for further extraction, this study aims to shift this previous focus to efficient resource use through dynamic analysis of anthropogenic metal cycle.
In this context, this study developed a holistic two-part methodology for this purpose. Firstly, a novel framework is proposed to address this challenge by incorporating three prominent systems (i.e. resource, material, and societal systems). This framework can help to reveal the critical role of the material cycle as well as its acceptable patterns in meeting the unprecedented needs within pressing resource constraints. Secondly, this study further developed an integrated material cycle model to offer the capability and flexibility in the dynamic analysis of various metals along its life cycle.
This proposed methodology was applied to address the status, obstacles, drivers, and strategies related to anthropogenic metal cycles. Three novel insights can be provided: Firstly, it has been highly inefficient in extracting, processing, using, and recycling of various metals. Such insight was found by quantifying the metallic resource flows, dissipative losses, and stocks of 55 different metals along their life cycles. Secondly, the resource constraint is severe that would jeopardise the future societal needs, which is revealed by the future analysis of the iron case. As iron has the most abundant geological and in-use stocks, the situation will be much worse for most metals as explored in the discussion section. Finally, the societal needs can be met with much less resource extraction through a collaboration of life cycle strategies. Herein, four major strategies (i.e. material efficient production, reduction, circularity, and efficiency) were assessed in the future analysis, which indicated a joint implementation of life cycle strategies (especially the material efficiency strategy) were required to satisfy desired affluence given pressing resource constraints.