Boston Metal has raised $75 million to push deeper into critical metals production, a move that gives the company a nearer-term commercial target while its larger green-steel ambition remains expensive and difficult to scale.
The company is best known for molten oxide electrolysis, a process it says can clean up steelmaking by using electricity instead of conventional carbon-heavy routes. Steel production is responsible for about 8% of global greenhouse gas emissions today, according to the source report. That makes the prize large. It also makes the path slow, capital-intensive, and exposed to policy and funding cycles.
The new round points to a more immediate business case: using the same core technology to produce higher-value metals such as niobium, tantalum, tin, vanadium, nickel, and chromium. Boston Metal’s Brazilian subsidiary is preparing a commercial facility for niobium, tantalum, and tin, and the new funding is expected to support that plant as well as future critical-metals projects.
What Boston Metal is funding now#
Boston Metal’s latest $75 million round includes existing investors and Tata Steel Unlimited, part of the major Indian steel company Tata Steel. The company has now raised more than $500 million in total, according to MIT Technology Review.
The immediate focus is Boston Metal do Brasil, the company’s subsidiary in Brazil. That facility is being set up to take in low-grade material and produce a mixture of critical metals. Construction started in 2024 and took about 18 months, but the official startup has been delayed.
CEO Tadeu Carneiro told MIT Technology Review that the new funding will help support the Brazilian facility’s operation and further work on other critical metals. He also said the company eventually plans to deploy a US plant to produce chromium. That matters because the US imports nearly all of its chromium supply today.
This is not a clean break from steel. It is a sequencing choice. Critical metals can carry higher prices than commodity steel, which may make them a better first commercial market for a difficult industrial technology.
The technology behind the plan#
Boston Metal’s core process is molten oxide electrolysis, or MOE. The system runs electric current through a reactor containing ore dissolved in a molten electrolyte. The electricity heats the material to about 1,600 °C, or 3,000 °F, and drives reactions that separate the target metal from the ore.
The metal collects at the bottom of the reactor, where it can be removed.
The same general approach can be applied to steel and to other metals. Boston Metal has already completed what MIT Technology Review describes as the largest run of its pilot industrial cell in Woburn, Massachusetts, producing about a ton of steel. That is a technical milestone, but not yet the same thing as a broad commercial steel rollout.
The current funding suggests the company is prioritizing metals where the economics are more favorable. Niobium, for example, is used in some steel alloys, jet-engine alloys, and superconducting magnets for MRI scanners. Tantalum is used in aerospace components such as rocket nozzles and turbine blades, and also in medical devices and electronics.
Those markets are smaller than steel. They can also tolerate higher prices because the metals are specialized and valuable. That gives Boston Metal a possible bridge: prove the reactor technology in a commercial environment before trying to change one of the largest industrial systems in the world.
Why critical metals may be the practical route#
Green steel faces a familiar industrial problem. The climate benefit is large, but buyers often resist paying a premium for a cleaner commodity material.
Seaver Wang, director of climate and energy at the Breakthrough Institute, framed the issue bluntly in the MIT Technology Review report: “Nobody wants to pay a green premium for steel—hence niobium.”
That line captures the business logic. Steel is enormous, price-sensitive, and embedded in global supply chains. Critical metals are different. They are tied to aerospace, medical devices, electronics, advanced manufacturing, and energy systems. Supply security can matter as much as unit cost.
For Boston Metal, this could make critical metals a proving ground rather than a detour. If the company can operate industrial MOE systems reliably, produce saleable materials, and show workable economics, it may strengthen the case for later steel deployments.
It also gives the company a better story at a time when support for industrial decarbonization has weakened in the US. Large climate-hardware companies often need patient capital, but investors still look for revenue paths. Critical metals may offer one.
The Brazil delay and cash-flow pressure#
The funding follows a difficult period for the company.
In January, Boston Metal’s Brazilian facility had an issue with its refractory system. That system insulates the reactor and helps prevent corrosion. According to Carneiro, the problem caused electrolyte to leak. Operators shut down the system and removed the metal. He said there were no injuries or environmental issues.
The reported impact was financial and operational. The leak delayed the plant’s opening. Because the company missed a milestone, it lost out on committed funding. Boston Metal then restructured and laid off staff, according to the source report.
Carneiro said the delay created “a big stress” in cash flow and that investors stepped in with support. The Brazilian facility is now being repaired and should be ready to start up in September 2026, he told MIT Technology Review.
That timeline should be treated as a company projection, not a completed milestone.
What not to overclaim#
The funding round does not prove that Boston Metal can decarbonize steel at scale. It does not prove that molten oxide electrolysis is commercially mature across all target metals. It also does not remove the execution risk at the Brazilian plant.
The more defensible read is narrower and more useful.
Boston Metal has raised new capital after a plant delay and cash-flow stress. It is putting more weight behind critical metals because those markets may support better near-term economics than green steel. Its technology has shown pilot progress in steel, but the company’s current commercial push is centered on higher-value materials.
That distinction matters. Climate technology companies often fail not because the physics is impossible, but because the first market is too hard, too cheap, or too slow. Boston Metal appears to be choosing a first market where the value per ton is higher and the strategic supply argument is stronger.
What to watch next#
The key test is the Brazilian facility. If repairs finish and startup happens around the projected September 2026 window, the next questions will be practical: uptime, product quality, throughput, cost, and customer demand.
Readers should also watch whether Boston Metal gives more detail on its planned US chromium project. Chromium has a clear supply-chain angle for the US, but a plan to deploy a plant is not the same as financing, permitting, building, and operating one.
The steel story remains important. But for now, Boston Metal’s near-term credibility may be built outside steel first. The company’s bet is that critical metals can keep the reactors running, the investors engaged, and the larger decarbonization case alive long enough to matter.