Measuring the “side effects” of tungsten recycling: Evidence from life cycle assessment

Tungsten (W), as “the teeth of modern industry,” is playing an irreplaceable role in the current industrial era due to its unique properties. Although the global primary tungsten supply is concentrated in China, the grade of such ore is deteriorating, leading to more consideration of promoting the reuse and recycling of tungsten scraps. However, the environmental impacts induced by tungsten recycling have not been investigated, which may influence the appropriate circular economy implementation along the entire tungsten industrial chain. This study aims to identify the “side effects” of tungsten recycling by comparing the pros and cons of primary/secondary tungsten production from a life cycle perspective. The environmental impacts of the primary tungsten production system (W-PPS), direct recycling system (W-DRS), and indirect recycling system (W-IRS) are estimated by using 18 mid-point indicators in human health, ecosystems, and resources categories. Results indicate that switching to W-DRS and W-IRS from W-PPS could help reduce environmental burdens in terms of major mid-point indicators, except human non-carcinogenic toxicity and terrestrial ecotoxicity. Energy and chemical raw materials input contribute the most to the above environmental impacts. Based upon these findings, we propose that serious regulations should be implemented for both primary and secondary production systems, as well as appropriate urban mine actions and sustainable industrial design schemes.