Green steel from red mud through climate-neutral hydrogen plasma reduction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38267679.
- Also identified by DOI 10.1038/s41586-023-06901-z and PMC identifier 10808056.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Red mud is the waste of bauxite refinement into alumina, the feedstock for aluminium production<sup>1</sup>. With about 180 million tonnes produced per year<sup>1</sup>, red mud has amassed to one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale<sup>1</sup>. Here we present how this red mud can be turned into valuable and sustainable feedstock for ironmaking using fossil-free hydrogen-plasma-based reduction, thus mitigating a part of the steel-related carbon dioxide emissions by making it available for the production of several hundred million tonnes of green steel. The process proceeds through rapid liquid-state reduction, chemical partitioning, as well as density-driven and viscosity-driven separation between metal and oxides. We show the underlying chemical reactions, pH-neutralization processes and phase transformations during this surprisingly simple and fast reduction method. The approach establishes a sustainable toxic-waste treatment from aluminium production through using red mud as feedstock to mitigate greenhouse gas emissions from steelmaking.