Bibliographic Details
| Title: |
Unraveling the thermodynamics and mechanism behind the lowering of reduction temperatures in oxide mixtures |
| Authors: |
Shankar, Shiv, Ratzker, Barak, da Silva, Alisson Kwiatkowski, Schwarz, Tim M., Brouwer, Hans, Gault, Baptiste, Ma, Yan, Raabe, Dierk |
| Publication Year: |
2025 |
| Collection: |
Condensed Matter |
| Subject Terms: |
Condensed Matter - Materials Science |
| More Details: |
Hydrogen-based direct reduction offers a sustainable pathway to decarbonize the metal production industry. However, stable metal oxides, like Cr$_2$O$_3$, are notoriously difficult to reduce, requiring extremely high temperatures (above 1300 $^\circ$C). Herein, we show how reducing mixed oxides can be leveraged to lower hydrogen-based reduction temperatures of stable oxides and produce alloys in a single process. Using a newly developed thermodynamic framework, we predict the precise conditions (oxygen partial pressure, temperature, and oxide composition) needed for co-reduction. We showcase this approach by reducing Cr$_2$O$_3$ mixed with Fe$_2$O$_3$ at 1100 $^\circ$C, significantly lowering reduction temperatures (by $\geq$200 $^\circ$C). Our model and post-reduction atom probe tomography analysis elucidate that the temperature-lowering effect is driven by the lower chemical activity of Cr in the metallic phase. This strategy achieves low-temperature co-reduction of mixed oxides, dramatically reducing energy consumption and CO$_2$ emissions, while unlocking transformative pathways toward sustainable alloy design. |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2504.12947 |
| Accession Number: |
edsarx.2504.12947 |
| Database: |
arXiv |
