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Steel to be manufactured in an environment-friendly process
Successful research is underway to produce steel of high purity, more environmental friendly and through scaling up of the new technology to get cheaper steel. The research is being carried out by MIT researchers who believe everything could be changed for the better with the present steel manufacturing technology for eventual reduction in the green house gases in the atmosphere.

Based on various reports, the following are the chief highlights of this study:

- Worldwide steel production currently totals about 1.5 billion tons per year. The prevailing process makes steel from iron ore - which is mostly iron oxide - by heating it with carbon, the process forms carbon dioxide as a byproduct. Production of a ton of steel generates almost two tons of CO2 emissions, according to steel industry figures, which is about 5 percent of the world's total greenhouse gas emissions.  

-Through research it has been found out that a process called molten oxide electrolysis could use iron oxide from the lunar soil to make oxygen in abundance, with no special chemistry. Testing was done using lunar like soil from Meteor Crater in Arizona - which contains iron oxide from an asteroid impact thousands of years ago. It was found that it produced steel as a byproduct.

- In the suggested method, it is reported that iridium anode could be used but since it is expensive and supplies are limited, therefore it may not be a viable approach for bulk steel production on Earth.  After more research was conducted, an inexpensive metal alloy has been found out which can replace the iridium anode in molten oxide electrolysis.

Researchers point out that it was not easy to solve this because a vat of molten iron oxide, which must be kept at about 1600 degrees celsius, is a really challenging environment. The melt is extremely aggressive while oxygen is quick to attack the metal. In the past, many researchers had tried to use ceramics, but these are brittle and can shatter easily. Researchers further point out that there are only two classes of materials that can sustain these high temperatures; metals or ceramics only a few metals remain solid at these high temperatures.

- It was not easy to do experiments at high temperatures and also the fact that the relevant expertise tends to be scattered across disciplines - "Electrochemistry is a multidisciplinary problem, involving chemical, electrical and materials engineering," according to the lead researcher. The problem was solved using an alloy that naturally forms a thin film of metallic oxide on its surface: thick enough to prevent further attack by oxygen, but thin enough for the electric current to flow freely through it. The answer turns out to be an alloy of chromium and iron; constituents that are abundant and cheap, according to the lead researcher.

- In addition to producing no emissions other than pure oxygen, the process lends itself to smaller-scale factories: Conventional steel plants are only economical if they can produce millions of tons of steel per year, but this new process could be viable for production of a few hundred thousand tons per year.

- Besides elimination of the emissions, the new process yields metal of exceptional purity. Further, more metals can be added to this process; this process could also be adapted to carbon free production of metals and alloys including nickel, titanium and ferro manganese, with similar advantages.

The above research was made possible with the support of American Iron and Steel Institute and the U.S. Department of Energy.

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