Recovering carbon black from end-of-life tires: A consequential life cycle assessment

Abstract

Closing loops, reducing resource consumption and environmental impacts are vital to tackle the climate-ecological crisis. Tire production demands non-renewable resources such as oil for carbon black production. This study analyzes the consequences of demineralization and activation processes to improve the quality of carbon black recovered from end-of-life tires by means of a pyrolysis process, using consequential life cycle assessment methodology. The outcomes show that high-quality, reinforcing recovered carbon black (HQR-rCB) leads to net environmental savings in two out of nine impact categories addressed, while still having net impacts on the other seven. The alternative scenarios analyzed show that excluding the demineralization process significantly changes the environmental impact profile of the system, achieving net environmental savings in seven out of nine impact categories while having much lower environmental impact in another one. Therefore, assessing the environmental impacts of post-treatment methods implemented to improve the quality of the rCB is mandatory, demonstrating that there should be a trade-off between quality and environmental sustainability. Overall, this study shows that achieving a better environmental sustainability profile goes beyond applying the circularity principle.