Boston Metal Secures $75 Million to Produce Critical Metals

Boston Metal, a startup known for its efforts to clean up steel production, has secured a $75 million funding round to produce critical metals, MIT Technology Review can exclusively report. The company, which has been working on reducing greenhouse emissions in the steel industry, responsible for about 8% of global emissions, will use the funds to support its commercial facility in Brazil and future efforts to produce critical metals like vanadium, nickel, and chromium. The funding comes at a crucial time for Boston Metal, which faced cash-flow problems following an industrial accident at its Brazil facility earlier this year.

The company's Brazilian subsidiary, Boston Metal do Brazil, is setting up a commercial facility to produce niobium, tantalum, and tin. Niobium, for example, is used in steel alloys, jet engines, and MRI scanners, while tantalum is used in aerospace applications, medical devices, and electronics. Boston Metal's core technology, called molten oxide electrolysis (MOE), involves running electric current through a reactor filled with ore dissolved in a molten electrolyte.

The process heats the mixture to about 1,600 °C (3,000 °F) and drives chemical reactions that separate the desired metal from the ore. In early 2025, the company completed the largest run of its pilot industrial cell in Woburn, Massachusetts, producing about a ton of steel. However, the company is currently focusing on producing more valuable metals, which can command a higher price.

The Brazilian subsidiary is working to test and start up an industrial-scale plant that takes in low-grade material and makes a mixture of critical metals. The funding will help support the plant's operation, which is expected to be ready to start up in September 2026, according to CEO Tadeu Carneiro. The new funding will also help support other critical metals projects, including a planned US plant to produce chromium, a metal that the country imports nearly all its supply of today.

Boston Metal has now raised over $500 million in total, with support from existing investors and the Indian steel company Tata Steel Unlimited. According to Seaver Wang, director of climate and energy at the Breakthrough Institute, making a higher-value critical metal now could help Boston Metal prove its technology and pave the way for future steel projects.