The archive · Climate & Energy · Technical decision · 2013–2026
Boston Metal bets molten oxide electrolysis scales; 1-ton reactor run, Brazil plant
MIT-born Boston Metal scales molten oxide electrolysis from lab cells to a 1-ton reactor run, then opens its first commercial plant in Brazil.
Boston Metal
What the business is
Boston Metal commercializes molten oxide electrolysis (MOE), an electric process that converts iron ore into molten iron and recovers metals like niobium from mining waste, emitting oxygen instead of CO2.
Starting capital：US$262M Series C total (initial round led by ArcelorMittal, closed September 2023) plus a US$51M convertible note announced 2025-07-15.
How it started
MOE was developed at MIT, and Boston Metal was founded in 2013 to commercialize it. For a decade the company moved from lab-scale reactors roughly the size of a coffee cup toward industrial scale, working on the hardest problem: inert anodes that degrade under the wrong conditions. A $262M Series C closed in September 2023 funded first-of-a-kind facilities in Boston and southeastern Brazil.
What happened
In January 2025 Boston Metal started up its industrial steelmaking reactor for the first time, and on February 17 it tapped out roughly a ton of material — a milestone MIT Technology Review called proof the process can scale. In July 2025 the company raised $51M more and pushed its first commercial plant in Minas Gerais, Brazil toward full scale, using MOE to recover niobium from mining waste while steel reactors keep scaling.
How it ended up
Live and scaling: the first commercial MOE plant in Brazil is coming online, the industrial steel reactor milestone is passed, and a larger steel demonstration plant is planned to come online in late 2026 with operations beginning in 2027.
Background
Boston Metal's bet is that molten oxide electrolysis can replace the coke-fired blast furnace. The process loads iron ore into a reactor, runs electricity through the molten mix at around 1,600 °C, and emits oxygen rather than carbon dioxide. With steel production at roughly 2 billion tons a year and more than 3 billion tons of CO2 emitted in the process, even a licensable electric route would be a massive market.
The company was founded in 2013 to commercialize MOE after it was developed at MIT, and spent a decade moving from coffee-cup-sized lab cells to industrial reactors. In January 2025 it started up its largest steelmaking reactor for the first time; on February 17 it tapped out roughly a ton of metal. MIT Technology Review reported the milestone exclusively, noting the company had solved the hardest scaling problem, keeping multiple inert anodes from degrading.
Commercialization runs in parallel: a $262M Series C closed in September 2023 with investors spanning ArcelorMittal, BHP, Saudi Aramco, and Breakthrough Energy Ventures, and in July 2025 the company raised $51M more as its first commercial plant in Minas Gerais, Brazil came online — initially recovering niobium, which sells for roughly $50,000 a ton. A larger steel demonstration plant is planned to come online in late 2026 and begin operation in 2027, with licensing to steelmakers as the endgame.
What has to be true
- Steel's scale makes any viable electric route a massive market if it can be licensed to existing producers.
- Proving MOE on niobium, a small but high-priced metal, created an early revenue path while steel reactors scaled.
- The multi-anode reactor run showed the core technical risk, inert anode degradation, was being solved.
- Investors from steel, mining, and oil hedged the technology's industrial buyers across the value chain.
What can be applied
Pick a small, high-margin market to prove a hard technology while the big market scales: niobium in Brazil funded Boston Metal's path to steel without waiting for a blast-furnace retrofit.
Aftermath
As of 2026-09-02 Boston Metal is live and scaling: it completed the first run of its industrial steelmaking reactor in January-February 2025, raised a $51M convertible note in July 2025, and was bringing its first commercial MOE plant in Minas Gerais, Brazil online, with full scale targeted for mid-2026. The company plans a larger steel demonstration plant online in late 2026 and operating in 2027, followed by licensing the process to steelmakers.
Sources
- This startup just hit a big milestone for green steel production
- Despite Trump cuts, green steel startup Boston Metal raised another $51 million
- Boston Metal raises $262m in green steel funding round
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