A life cycle analysis on magnesium production processes: Energy consumption, carbon emission and economics

Magnesium is widely used in manufacturing industry because of its excellent physical and chemical properties and has its increasing demand due to environmental requirements. China, as the world s biggest producer and exporter of metallic magnesium, produces metallic magnesium in its western provinces through the silico-thermic process known as the Pidgeon process. However, there are few metallic magnesium plants in eastern China, especially in Liaoning province where magnesite is rich in reserves. The short supply of magnesium has limited the growth of the magnesium casting industry and the local magnesite industry. Under the carbon market established to face the challenges of climate change, how to choose an economical and feasible route for magnesium production, is a key factor to determine the development of magnesium industry in Liaoning. In this paper, life cycle analysis models are developed to study the energy consumption, greenhouse gas (GHG) emissions, and economics from cradle to gate for six different metal magnesium production processes using data accounting for different geographical environments, process equipment, and energy supply pathways based on the Chinese Life Cycle Database (CLCD). The influence of carbon trading prices on economic performance of the six processes is also investigated. Compared with the current process widely used in China, the new magnesium production technology using Liaoning s abandoned magnesite as raw material and the coke oven gas from steelworks as fuel showed the best economic performance in terms of cost for greenhouse gas emissions.