Maintaining and improving sustainability in steel in the 21st Century will depend on the transfer of technology from the laboratory to the mill floor, according to many industry players.
But with a few exceptions, that technology, at least for the foreseeable future, will lead to incremental advancements rather than revolutionary new processes. And because steel is so capital-intensive, industry leaders will have to be convinced of the economic benefits of investing millions, if not billions, of dollars in new, sustainable technologies.
"Nobody is green for the sake of being green," said Richard J. Fruehan, co-director of Carnegie-Mellon Universitys Center for Iron and Steel Research in Pittsburgh. "There has got to be an economic incentive."
For many steelmakers, the economic incentive to do things differently came with an unprecedented increase in ferrous scrap prices. In 2008, prime industrial scrap surged to around $900 per ton, shocking scrap buyers across North America. The jump was the result of several factors, including a shortage of industrial scrap in the United States as well as demand from mills in China, the Far East and Turkey. Scrap prices dropped dramatically in 2009, buffeted by the most severe recession in three-quarters of a century, but the sector recovered strongly last year and predictions of an imminent return of shortages came true this year.
The electric-arc furnace (EF) steel industry has long sought an alternative source of material for its furnaces, but direct-reduced iron, hot-briquetted iron and other alternative metallic commoditiesmost of which are imported by the United Stateshave been consistently higher priced than scrap.
Donald Fosnacht, director of the Center for Applied Research and Technology Development at the Natural Resources Research Institute in Duluth, Minn., said that the group is working with steel companies to develop a linear hearth process for making iron-rich nuggets. Similar to a traveling grate process, the linear hearth, which has reached the prototype stage, would make iron nodules of about the same richness of Mesabi nuggets.
"If you look at the emissions profile, there is a significant benefit in terms of CO2 reductionas much as 25 to 30 percent compared to reducing taconite pellets in the blast furnace. We feel it is something that could definitely impact the CO2 picture for the industry," Fosnacht said.
Scientists at Torontos McMaster University, in cooperation with Luxembourgs ArcelorMittal SA, are examining the feasibility of paired straight hearth furnaces. The furnaces, similar to those employed in the Minnesota project, are paired side by side in an attempt to reduce a bed of pellets or nuggets stacked 10 to 12 deep in the furnace, thereby greatly improving productivity.
Current plans for the $20-million research and development project, which is being partially funded by the U.S. Energy Departments Industrial Technology Program, call for construction of a laboratory pilot facility with a capacity of 50,000 tons per year. Experiments also are ongoing with plans to modify the paired hearth furnaces to process steelmaking waste oxides to make a viable iron feed material for use in EFs.
The rotary, linear and paired hearth furnaces arent the only sustainable technologies envisioned for the iron side of the steelmaking equation. Other researchers in the Lake Superior basin are studying the feasibility of magnetation, a process that would use electromagnets to strip iron from the millions of tons of ore tailings and poor rock that dot Minnesota, Michigan, Wisconsin and other mining regions.
The American Iron and Steel Institute and the industry it represents are backing the CO2 Breakthrough Program, an ambitious research and development effort designed to identify and implement the steelmaking technologies of tomorrow.
Several technologies currently being studied hold the promise of revolutionizing steelmaking, according to Joe Vehec, senior director of collaborative research at the AISIs Pittsburgh office who works with the CO2 Breakthrough Program. "We are always looking for new and energy-efficient ways of making steel with minimal emissions," he said. "And weve made great improvements in energy efficiency through incremental technologies and best management practices."
One of those technologies seeks to produce steel using hydrogen as a fuel source. Much as automotive researchers envision a world in which hydrogen will power many of the worlds vehicles, steel industry researchers are looking at ways to make steel in hydrogen-fueled furnaces. Since 2009, the AISI has partnered with researchers at the University of Utah in testing a flash suspension process in which iron ore fines literally melt in the air. "Weve already got a pilot facility in Utah where were evaluating the parameters of the project," Vehec said. "We are in the process of building a bigger reactor." The new reactor will triple the reactor zone of the pilot plant and allow the researchers to scale up the project to achieve industrial hardening of the steel. The capacity of the new reactor will eventually reach nearly 100,000 tons of steel annually.
Vehec stressed that AISIs CO2 Breakthrough Program projects are "technical solutions looking far out in the future."