In a statement, ArcelorMittal said it is investing US$36 million and is joined in the funding round by Microsoft’s Climate Innovation Fund and others. 

Boston Metal is commercializing a molten oxide electrolysis process that can convert low- and mid-grade iron ore fines directly into high-purity molten iron. The iron can be sent directly to ladle metallurgy without the need to reheat, according to the company. 

Boston Metal said the Series C funding will provide for expanded production of green steel at the company’s pilot facility outside Boston, Mass., USA,  and will support the site selection and preliminary design of its first green steel plant. It also will support the construction and commissioning of a manufacturing facility for high-value metals at the company’s Brazilian subsidiary, Boston Metal do Brasil.

ArcelorMittal is making the investment through its XCarb Innovation Fund, which was established in 2021 to support development of technologies with potential to play a meaningful role in decarbonization of the steel industry. 

The investment is the fund’s largest to date, said ArcelorMittal, which will now have a seat on Boston Metal's board. 

“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 revolutionize steelmaking,” said ArcelorMittal chief executive Aditya Mittal. “In our extensive discussions with them, we have been impressed by the passion and vision they have to contribute to the decarbonization of steelmaking. They are an exciting and welcome addition to the XCarb Innovation Fund’s portfolio.”