Prospective environmental assessment of reprocessing and valorization alternatives for sulfidic copper tailings

Abstract

Waste from primary mining operations, especially mine tailings, receive much attention as potential secondary resources that can transform liabilities into resources. The primary intention is to minimize mine tailings disposal problems through volume reduction while recovering secondary resources for industrial materials. However, the environmental benefits and tradeoffs behind these objectives remain unclear. This study conducts a process-based life cycle assessment (LCA) study to investigate multiple reprocessing pathways of copper tailings to co-produce secondary metals and building materials. Four design options representing different value-recovery routes are constructed to assess the environmental burdens of reprocessing chains and the associated benefits from displaced virgin products. This study assesses emerging technologies in a prospective LCA, with projections of bottom-up foreground process modeling and background data like energy supply scenarios. Our analysis reveals that the assessed technologies can only be beneficial when all co-products are utilized. Results indicate that reprocessing may save from 25 up to 930 kg CO2-eq per tonne of treated copper tailings. Potential environmental benefits depend on the reprocessing routes, technology upscaling parameters, and quality of secondary products. We propose recommendations to enhance the environmental performances of mine tailings reprocessing strategies, such as switching to low-impact chemical alternatives and optimizing energy use. Our findings can support the sustainable development of the metal industry in terms of waste management and secondary resource use.