Skip to Content
77 Mass Ave

Eco-Friendly Steelmaking

Emissionless method could curb a major source of greenhouse gases

Conventional steelmaking may be the world’s leading industrial source of greenhouse gases. But a new process developed by MIT researchers could change all that—and produce stronger (and ultimately cheaper) steel.

Antoine Allanore and Donald Sadoway
Antoine Allanore (left) and Donald Sadoway

Worldwide steel production currently totals about 1.5 billion tons per year, and each ton produced generates almost two tons of carbon dioxide, according to industry data. This accounts for about 5 percent of the world’s greenhouse-gas emissions.

The idea for the new method, which was developed by materials chemistry professor Donald Sadoway, assistant professor of metallurgy Antoine ­Allanore, and Lan Yin, PhD ’12, arose when ­Sadoway received a grant from NASA to look for ways of producing oxygen on the moon—a key step toward future lunar bases. He found that a process he invented called molten oxide electrolysis could use iron oxide from the lunar soil to make oxygen in abundance.

This method used an iridium anode, but since iridium is expensive and supplies are limited, that’s not a viable approach for bulk steel production on Earth. Finding an alternative wasn’t easy, because molten iron oxide, at about 1,600 °C, “is a really challenging environment,” Sadoway explains. “The melt is extremely aggressive. Oxygen is quick to attack the metal.”

But Allanore managed to solve the problem. The answer was 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 electric current to flow freely through it. The alloy’s constituents, iron and chromium, are “abundant and cheap,” Sadoway says.

In addition to producing no emissions other than pure oxygen, the process lends itself to smaller-scale factories. Conventional steel plants are profitable only 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, he says.

The process also yields metal of exceptional purity, Sadoway says. And it could be adapted for carbon-free production of other metals and alloys, including nickel, titanium, and ferromanganese.

The technology is still at the laboratory scale, but Sadoway, Allanore, and a former student have formed a company to develop a commercially viable prototype plant. They expect that designing, building, and testing such a facility could take about three years.

Keep Reading

Most Popular

A Roomba recorded a woman on the toilet. How did screenshots end up on Facebook?

Robot vacuum companies say your images are safe, but a sprawling global supply chain for data from our devices creates risk.

A startup says it’s begun releasing particles into the atmosphere, in an effort to tweak the climate

Make Sunsets is already attempting to earn revenue for geoengineering, a move likely to provoke widespread criticism.

10 Breakthrough Technologies 2023

Every year, we pick the 10 technologies that matter the most right now. We look for advances that will have a big impact on our lives and break down why they matter.

These exclusive satellite images show that Saudi Arabia’s sci-fi megacity is well underway

Weirdly, any recent work on The Line doesn’t show up on Google Maps. But we got the images anyway.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.