US green steel technology company Boston Metal has sealed a $120m first close of Series C fundraising, led by multinational steel giant ArcelorMittal and backed by new investors such as Microsoft’s Climate Innovation Fund and SiteGround Capital.

Steelmaking accounts for almost 10% of global carbon emissions. (Photo by Monty Rakusen via Getty Images)

Boston Metal’s patented molten oxide electrolysis (MOE) process is used to produce both green steel – swapping fossil fuels for clean electricity to eliminate carbon emissions – and high-value metals such as tin and niobium. The company will use the new funding to expand the production of green steel at its pilot facility outside Boston, Massachusetts, as well as to support the site selection and preliminary design of its first green steel plant. In addition, the funds will support the creation of a manufacturing facility for high-value metals at Boston Metal’s Brazilian subsidiary, Boston Metal do Brasil.

Boston Metal’s MOE green steel technology uses renewable electricity to convert all iron ore grades into steel via an energy-efficient, one-step process. The technology does not release carbon dioxide or other harmful byproducts, and there is no need for process water, hazardous chemicals or precious-metal catalysts.

Boston Metal do Brasil is also using MOE to advance the efficiency, sustainability and profitability of its metals production. The technology selectively extracts valuable metals from complex, low-concentration materials currently considered to be waste, enabling miners to reduce the financial and environmental liabilities of slag by using this natural byproduct of metal production to create new revenue streams. 

“In Boston Metal, we are investing in a team that has made impressive progress over a relatively short period of time, developing a technology that has exciting potential to revolutionise steelmaking,” said ArcelorMittal CEO Aditya Mittal in a statement. “In our extensive discussions with them, we have been impressed by the passion and vision they have to contribute to the decarbonisation of steelmaking.”