In an ongoing effort to decrease carbon emissions in their manufacturing processes, steelmakers are funding research at the Massachusetts Institute of Technology (MIT) that could one day eliminate the need for baking iron ore in blast furnaces.
Iron is an ingredient in steel. The iron-derivation process in integrated mills requires blasting iron ore in huge coke-fired ovens, a process that is the most visually familiar image of steelmaking but also is the largest contributor to carbon emissions.
The American Iron and Steel Institute (AISI), a Washington, D.C.-based trade group for major North American producers, has contracted with MIT professor of materials science Donald R. Sadoway to research the feasibility of a new way to derive iron. Called "molten oxide electrolysis," the method applies electricity to a metal oxide feedstock with the result being separated metal and oxygen. A similar process is used already by the aluminum industry, but steelmaking would require it be done at higher temperatures, part of the process that must be vetted.
According to Lawrence Kavanagh, vice president for manufacturing and technology at AISI, the new technology will be studied on a small scale for two years; if success is met, it will continue at a large-scale study for five years. Potentially, it could be in the field in a decade.
"These things take a long time to develop, so you have to get on them," Kavanagh says.
"The blast furnaces that are in operation today will be in operation 10 years from now. But how many off those will be in operation 10 years from then?"
This is not the only technology the steel industry has considered and/or used to reduce emissions. Earlier this year, AISI reported that the U.S. steel industry furthered an ongoing reduction in energy usage by 7% from 2002 to 2003, contributing to a 23% drop in energy usage since 1990.
The metal oxide electrolysis would reduce emission from the actual burning of ore as well as the use of coke to stoke the ovens. It's this combination of process change and energy reduction that excites Sadoway. ". . . in conjunction with carbon-free electricity [metal oxide electrolysis] will usher in the era of sustainable metallurgy," Sadoway says. "Depending on the extent of success of the project, this research could break major new ground in terms of CO2 emissions reductions."
