The steel industry, long singled out as one of the world's leading industrial sources of greenhouse gases, may be getting a green make-over.
Researchers at the Massachusetts Institute of Technology, MIT, have announced a breakthrough process for making steel without carbon dioxide emissions.
An estimated 1.5 billion tons of steel are currently produced worldwide yearly and the prevailing process makes steel from iron ore by heating it with carbon, which in turn forms carbon dioxide as a byproduct, says a report by Science Codex.
According to steel industry statistics, the production of one ton of steel generates almost two tons of CO2 emissions. Based on those figures, the steel industry is responsible for as much as 5 percent of the world's total amount of greenhouse-gas emissions.
The new MIT-developed production process --- detailed in a paper by senior author Donald Sadoway, a professor of materials chemistry, and published in the journal Nature --- is called molten oxide electrolysis and uses iron oxide from the lunar soil to produce oxygen with no special chemistry.
The industry has had little success in the past looking for carbon-free methods of manufacturing steel.
The idea for the new method arose when Sadoway received a grant from the National Aeronautics and Space Administration to find ways for producing oxygen on the moon, a key step in developing future bases there.
Sadoway tested the process by using lunar-like soil from Meteor Crater in Arizona, which contains iron oxide from an asteroid impact thousands of years ago.
Initially, Sadoway's method used an iridium anode for the process, but since iridium is expensive and supplies are limited, it did seem a viable resource for bulk steel production.
After more research and input from study co-author Antoine Allanore, a professor of metallurgy who used to work in the steel industry, the MIT team identified an inexpensive alloy of chromium and iron to replace the iridium anode in molten oxide electrolysis.
The process, Sadoway was reported saying by Science Codex, could ultimately produce a steel of high purity without producing greenhouse gases and prove more economical than traditional forging methods.
The new steel-making the process could also be a viable production for smaller-scale factories that would need to produce, say, only a few hundred thousand tons of steel per year, in contrast to steel plants now that are only economical if they can produce millions of tons of steel yearly.
Sadoway said the process could also be adapted to the carbon-free production of metals and alloys like nickel, titanium and ferromanganese.
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