Environmentally Sound Metal Production
Imagine if the by-product of the metal produced in a smelter were oxygen instead of carbon dioxide. Molten oxide electrolysis (MOE), a transformational technology that can dramatically mitigate greenhouse gas emissions from ironmaking, has been successfully demonstrated at the laboratory-bench scale at MIT under sponsorship from the American steel industry through the American Iron and Steel Institute. By the action of electric current alone (in the complete absence of carbon or any other chemical reductant), iron oxide is converted directly to pure liquid iron; oxygen gas is the by-product. MOE emits no CO2, no SO2, and no NO, while producing liquid metal of superior quality, as one would expect from a high-efficiency electrochemical process, plus high-purity oxygen as by-product. The potential for energy productivity improvement is significant. We estimate energy efficiency gains at the industrial scale as high as 50% over today’s highly efficient integrated steel plants.
MOE is in a very real sense a platform for a suite of metal producing technologies. In our labs at MIT we have demonstrated the primary extraction of not only iron but also nickel, ferromanganese, ferrochromium, ferrosilicon, titanium, and zirconium. MOE has all the attributes of a 21st century metal production technology: (1) reduce environmental impact, (2) reduce metal production costs: operating and capital, (3) provide flexibility in raw materials, and (4) improve metal quality.
Funding for on-campus research currently comes from ONR (Office of Naval Research). Collaborators of Sadoway, Antoine Allanore and Jim Yurko, have been recognized for research in the area of MOE with the 2012 Vittorio de Nora prize for Environmental Improvements in Metallurgical Industries. Sadoway and Allanore have described their way to make cheap steel without greenhouse-gas emissions using a new anode material in the publication Nature
Collaborators of Sadoway have been recognized for research in the area of MOE with the 2012 Vittorio de Nora prize for Environmental Improvements in Metallurgical Industries.
In parallel, scale-up to an industrial prototype electrolysis cell is being pursued at Boston Electrometallurgical Corporation, a start-up company co-founded by Sadoway, Allanore and Yurko. Boston Electromet recently received significant private funding to realize the scale-up goals.
Recent publications on the topic:
- A. Allanore, L. Yin, and D.R. Sadoway, “A new anode material for oxygen evolution in molten oxide electrolysis,” Nature, 497(7449), 353–356 (2013), doi:10.1038/nature12134.
- H. Kim, J. Paramore, A. Allanore, and D.R. Sadoway, “Electrolysis of molten iron oxide with an iridium anode: the role of electrolyte basicity,” J. Electrochem. Soc., 158 (10), E101-E1-5 (2011).
- S. Poizeau and D.R. Sadoway, “Towards a Design Tool for Self-heated Cells Producing Liquid Metal by Electrolysis,” in Light Metals, TMS, Hoboken, NJ, pp. 387-392 (2011).
- D. Wang, A.J. Gmitter, and D.R. Sadoway, “Production of oxygen gas and liquid metal by electrochemical decomposition of molten iron oxide,” J. Electrochem. Soc., 158 (6), E51-E54 (2011).
- A.T. Vai, J.A. Yurko, D.H. Wang, and D.R. Sadoway, “Molten Oxide Electrolysis for Lunar Oxygen Generation Using In-Situ Resources,” Jim Evans Honorary Symposium, eds. B.Q. Li, B.G. Thomas, L. Zhang, F.M. Doyle, and A.P. Campbell, TMS Annual Meeting 2010, Seattle Washington, pp. 301-308 (2010).