How to make emission-free iron at temperatures cooler than coffee

Iron, of course, makes up 98% of the substance of steel, the ubiquitous material from which the modern world is built. In furnaces heated with coal to over 1,400°C (2,500°F), the carbon in the coal combines with the oxygen in the iron ore to separate impurities and unwanted oxygen atoms, releasing vast amounts of carbon dioxide.

The iron then goes through a series of steps to become steel, but the iron creation step accounts for 90% of the greenhouse gases generated. Steel production is responsible for 7% of greenhouse gas emissions released into the air each year, more than the climate impact of shipping and aviation combined. Producing iron at warm temperatures and without coal would avoid the heavier step of emissions without relying on expensive technologies.

That’s why Nijhawan’s idea caught Danielson’s eye: Affordable green steel is a big deal and could disrupt an industry that generates more than $870 billion in revenue each year. With the green light to go ahead and $2.25 million from BEV and other investors, Nijhawan launched Electra, in stealth mode, to do just that.

put electrons to work

Stereotypically for a startup, Electra began its experiments in a garage. Nijhawan’s former colleague, Quoc Pham, came on board as chief technology officer. His first work was to find out if it is possible to dissolve iron ore in water mixed with acid.

The failure came in a matter of weeks. “I have bad news for you,” Pham told Nijhawan. “This could be the shortest start-up of my life.”

To understand what went wrong, let’s look at the three known ways you can reduce emissions from steelmaking.

First, capture the emissions generated by the process and bury them deep underground. The first such plant was built in 2016 in the United Arab Emirates, but thanks to the initial expense of carbon capture technology, none have been built since then.

Second, use hydrogen as a replacement for carbon. The first shipment of hydrogen-based steel was produced last year, but commercial volumes won’t be available until 2026. And since hydrogen produced from renewable electricity remains more expensive than coal, companies are forced to use high quality iron ore, which there is not much of.

“The world is running out of high-quality ores available for steelmaking,” says Nijhawan.

Third, use electricity. Metals such as aluminium, copper and zinc are made with electricity, admittedly in much smaller quantities than iron. Until electricity became cheap, it was not economical to think of applying it to iron production.

However, electricity cannot pass through solid iron ore. One solution is to melt it. That’s what Boston Metal Co., a startup founded in 2012, has done. For the past 10 years, it has been perfecting and scaling the technology, which works by heating iron ore to 1,400°C using enough electricity to power thousands of homes. and concentrating it in a metal box not much bigger than a dumpster.

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Concentrating so much electricity in such a small area has to be done using special materials. Boston Metal can do this by using carbon as an electrode, a piece of equipment that allows energy to flow without melting, but that also creates carbon dioxide, defeating the purpose of using green electricity. Boston Metal found an alternative material made of iron and chrome, but so far it’s only working on a pilot scale.

Nijhawan did not want to melt anything. Once he has a process running at molten metal temperatures, he has to run 24 hours a day, 365 days. If it stops, the ore solidifies and new deposits need to be installed, causing months of delay. So the process had to be “benign from a temperature perspective,” he says, nothing hotter than the temperature at which “coffee is brewed.” That would allow for easy startup and shutdown, and would allow reliance on intermittent renewables. But getting the process to work at such a low temperature required Pham to dissolve the iron ore in water mixed with acid.

“My speech to all [the investors] was: ‘Look, I don’t know if this can be done. I pondered the problem and asked the experts. I think there is a feasible path,” says Nijhawan. “All I need is less than 10 people and maybe a year or a year and a half to get this up and running.”

He didn’t have to wait that long. Pham went back to the drawing board, reading the scientific literature and consulting experts, including Dan Steingart, a professor of chemical metallurgy at Columbia University. After weeks of trying new experiments, he found a successful solution.

Electra is now exiting stealth mode and is refusing to publicly disclose her exact process. However, Nijhawan and Pham shared enough details for independent experts to confirm that what the company claims to do is technologically feasible.

“Electra has managed to pull off a difficult conversion going from iron oxide to iron using only electricity at such low temperatures,” says Venkat Viswanathan, an associate professor at Carnegie Mellon University. “The steps they take are iron to be in the right state.”

A tour of the company’s Colorado facility also highlights its progress. There is no coal furnace or molten metal, and laboratory demonstrations show how iron ore can be dissolved. After running the electrical process, Electra produces office paper-sized plates with a thick layer of iron metal on them, silver-gray in appearance and surprisingly heavy.

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The success of those experiments has helped Electra raise $85 million in total from BEV, mining giant BHP Group, Singapore-based fund Temasek Holdings, Amazon Inc. and a few other investors. Now you just have to scale the technology.

Iron Age continued

Electra promises to build a facility next year that will have several commercial-size iron sheets; a few years later, he plans to make thousands of plates in a larger factory. With Swedish steel giant SSAB aiming to produce commercial quantities of carbon-free steel by 2026 and Boston Metal promising to produce emission-free iron by 2026, the race is officially on.

A full-size commercial Electra plant would be much smaller than conventional steel plants, which can generate 2 million metric tons of steel a year, cost more than a billion dollars, and are so large that entire towns spring up around them. Electra will look to build plants that make just 300,000 tons of steel each year, a size that would allow the startup to locate near existing electric arc furnaces. These furnaces take scrap steel and recycle it, and can also use the iron that Electra produces and modify the process to add more virgin iron than scrap steel.

Another advantage could be locating Electra plants near iron ore mines, which are typically far from urban centers and near land where renewable energy can be built. Electra’s plants could then process the ore into iron on site and remove all impurities, dramatically reducing the volume of material that must be transported to a steel plant and further lowering costs.

It could even be Electra’s first commercial app. By devising a process to dissolve the iron ore, the company was also able to remove impurities much more easily than conventional steelmaking: at lower temperatures, the impurities do not react chemically as they would in a 1600°C furnace. The world sits on billions of tons of low-grade iron ore. It could be possible for Electra to build factories near those mines and make existing operations economically viable.

“Do or die in a startup is real,” says Nijhawan. “You don’t have 10 years to develop new science. You have to be in that pressure cooker, to be honest with you, instead of having infinite time on hand and resources on hand to see what can be done differently.”

(By Akshat Rathi, with assistance from Christine Driscoll and Oscar Boyd)

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