Manganese Alloy ProductionA Review of the SAF Process and Emerging Technologies

Manganese alloys are essential to the steel-making industry, where they are primarily produced in submerged arc furnaces (SAFs) using a mixture of manganese ores, slags, and carbon-based reductants. However, this production process is one of the leading sources of greenhouse gas emissions, contributing to global warming and conflict with the International Energy Agency's Sustainable Development Goals targeting net-zero emissions by 2050. This review critically examines the key process variables, including slag composition, reductant type, raw material properties, particle size, and operating temperature, and their influence on environmental performance. Emerging technologies aimed at decarbonizing Mn-alloy production are evaluated in terms of technical maturity and scalability. Among these, biocarbon substitution, particularly the use of charcoal in place of coke, has demonstrated the highest commercial readiness, with several facilities operating at full scale. Hydrogen-based reduction and plasma arc furnaces offer promising long-term solutions but require substantial infrastructure development. Integrated approaches such as the Duplex FeMn-DRI, HAlMan, and AlloyStream processes show potential for circular resource utilization, though most remain at the pilot scale. Overall, biocarbon-based methods currently represent the most viable pathway for near-term decarbonization, while continued innovation and investment are essential to advance other technologies toward industrial implementation.