Comparative life cycle assessment of conventional and new fused magnesia production

Due to the antiquated processes, fused magnesia (FM) production in China causes many problems such as high energy consumption and heavy greenhouse gas emissions, which have gradually become a barrier to the future sustainable development of the industry. These issues are creating pressure to find alternative processes that can reduce energy consumption and pollution in the industry, while guaranteeing the quality of products. We develop a transparent life cycle inventory of two conventional and two new FM processes from magnesite mining to FM production and apply the inventory to conduct a cradle-to-gate life cycle assessment of four scenarios, including: Scenario 1 (S1) – a Single Phase Process using natural magnesite as raw material; Scenario 2 (S2) – a Two Phase Process using caustic calcined magnesia as raw material; Scenario 3 (S3) – an alternative process based on raw material substitution; and, Scenario 4 (S4) – another alternative improving from the overall process. Results indicate that in two traditional processes, S1 is superior to S2 in terms of environmental impacts. However, the two alternatives show significant differences. S3 doesn't reduce the environmental impacts as a whole, but transfers them from the production phase to other raw material production phases. S4 has the best environmental performance with an effective reduction of each impact category, especially the global warming potential (GWP), which was reduced by 48% compared to S1. The study shows that promoting the sustainable development of the FM industry requires overall process improvement to ensure comprehensive utilization of resources and energy and reduce greenhouse gas emissions.