Green steel from red mud through climate-neutral hydrogen plasma reduction

Red mud, the highly alkaline waste from the Bayer process in alumina production, has accumulated to about 4 billion tonnes globally and grows by ~180 million tonnes per year. The study demonstrates a fossil-free, hydrogen plasma-based single-step reduction that converts red mud directly into liquid iron, enabling green steel production while neutralizing the waste. The process proceeds via rapid liquid-state reduction, chemical partitioning, and density/viscosity-driven separation between metallic and oxide phases. The authors elucidate the underlying redox reactions, pH-neutralization, and phase transformations, showing that red mud can be transformed into a valuable feedstock for ironmaking without direct CO2 emissions, thereby linking sustainable waste management in aluminium production to low-carbon steelmaking.

Matic Jovičević-Klug, Isnaldi R. Souza Filho, Hauke Springer, Christian Adam, Dierk Raabe