Boston Metal raised $75 million to expand its critical metals business, the company announced this week. The pivot away from green steel production reflects a broader survival strategy among climate tech firms after the Trump administration slashed federal decarbonization support. “By deploying in the critical metals industry where we can go very fast, we generate the resources to continue with the development of steel,” CEO Tadeu Carneiro told MIT Technology Review.
The funding round drew new and existing investors, MIT Technology Review reported on May 21. Boston Metal will use the capital to scale production of niobium, tantalum, chromium, and vanadium — metals the US government classifies as critical for aerospace, defense, and energy supply chains. The company’s flagship steel-decarbonization project, which produced its first ton of material at a Massachusetts pilot reactor last year, now takes a back seat.
Carneiro’s logic is straightforward. Steel is a low-margin, high-volume business. Critical metals command higher prices. “We generate the resources to continue with the development of steel,” he said.
The company’s molten oxide electrolysis technology, which uses electricity to extract metals from ore, works for both. The same process that could one day cut steel’s 7% share of global carbon emissions can also produce niobium for jet engines and tantalum for capacitors. The strategy is spreading.
Brimstone, a California-based cement startup, now prominently features critical minerals on its website. Its process makes not only low-carbon cement but also alumina, a raw material for aluminum production. Last year, the Department of Energy canceled $1.3 billion in funding for cement-related projects, hitting Brimstone and Sublime Systems.
A Brimstone representative called the cancellation a “misunderstanding,” noting the funded facility would produce alumina alongside cement. That dual-purpose pitch now anchors the company’s public messaging. Carbon dioxide removal companies are joining the trend.
Some are partnering with mining operations, pitching their technology as a way to extract minerals more efficiently or clean up abandoned mine sites. The shift is part of a broader messaging realignment across the energy sector. Politicians and corporate leaders talk less about climate and more about energy abundance, data centers, and supply chain security. “Suddenly, it feels like every climate tech company has a story to tell about topics that are politically in vogue: data centers, energy abundance, or critical minerals,” wrote Casey Crownhart, author of The Spark newsletter for MIT Technology Review.
The trend makes her nervous. “I worry that if we keep too quiet on climate, companies might lose the plot and make choices that won’t help cut emissions.”
The numbers explain the anxiety. Steel accounts for roughly 7% of global CO2 emissions. Cement adds another 8%.
Decarbonizing these industries is essential to meeting Paris Agreement targets. Yet the Inflation Reduction Act’s climate provisions face ongoing political attacks. The Department of Energy under the second Trump administration has redirected funds toward fossil fuel infrastructure and critical mineral independence.
For startups, the message is clear: adapt or die. Boston Metal’s $75 million raise is modest by industrial standards. A single steel plant can cost over $1 billion.
The company’s pivot to critical metals buys time. Niobium sells for around $40 per kilogram. Tantalum can fetch over $200 per kilogram.
Steel, by comparison, trades at less than $1 per kilogram. The economics favor specialization, even if the climate impact shrinks. The critical minerals market is growing fast.
The International Energy Agency projects demand for minerals like lithium, cobalt, and rare earths will quadruple by 2040. The US Geological Survey lists 50 minerals as critical to national security. Niobium and tantalum are on that list.
Chromium and vanadium are used in steel alloys and batteries. For Boston Metal, the pivot is also a geopolitical play. China dominates global processing of many critical minerals.
US policymakers want domestic alternatives. Brimstone’s alumina production fits the same narrative. The US imports nearly all its alumina.
A domestic source, even as a byproduct of cement, strengthens supply chains. The company’s website now leads with “Critical Minerals” before mentioning cement. Sublime Systems, the other cement startup hit by funding cuts, has not publicly announced a similar pivot.
Its silence may signal a different strategy — or a slower adaptation. The carbon removal sector’s mining pivot is more tenuous. Companies like Heirloom and CarbonCure have explored partnerships with mines.
The idea: use mine tailings, which are rich in reactive minerals, to capture CO2 from the air. Others propose using captured carbon to extract metals from ore. These approaches are early-stage.
The revenue potential is unclear. But the political winds favor anything that reduces reliance on China. Crownhart’s MIT Technology Review piece captures a moment of quiet desperation.
Climate tech companies are not abandoning their missions. They are hiding them in plain sight. A steel decarbonization company becomes a critical minerals supplier.
A cement startup becomes an alumina producer. The climate benefits, if they come, will arrive years later than planned. The strategy carries risks.
Investors may lose patience with dual-purpose companies. Critical minerals markets are volatile. A niobium glut could crash prices.
Policy support for domestic mining could fade with the next administration. And the longer companies delay full-scale decarbonization, the harder it becomes to meet 2030 and 2050 climate goals. Yet the alternative is worse.
Without revenue, these startups disappear. Their technologies, developed over years with millions in venture capital and government grants, would be lost. “For some, leaning into a different priority or pushing a different message could help them stay in business long enough to make a difference,” Crownhart wrote. “We’ll all have to wait to see how it all pans out.”
That waiting is the hard part. The climate clock ticks. Emissions rise.
The politics of decarbonization remain toxic in Washington. In this environment, survival is a form of progress. Boston Metal’s Carneiro, a veteran of the metals industry, understands the long game.
He spent decades at Brazilian mining giant Vale before joining the startup. His bet: critical metals today, green steel tomorrow. Why It Matters: The survival of climate tech companies affects whether the US can decarbonize heavy industry by 2050.
If startups like Boston Metal and Brimstone fail, the technologies needed to cut steel and cement emissions may never scale. Their pivot to critical minerals keeps them alive but delays climate benefits. For communities near steel mills and cement plants, that means continued pollution.
For the planet, it means a slower path to net zero. Key takeaways: - Boston Metal raised $75 million to produce critical metals like niobium and tantalum, deprioritizing its green steel technology. - Brimstone and other climate startups are similarly pivoting to critical minerals after federal decarbonization funding was cut. - The strategy generates revenue but delays emissions reductions in steel and cement, which together account for 15% of global CO2. - The shift reflects a broader political reality: under the Trump administration, supply chain security sells better than climate action. What comes next: Boston Metal plans to scale its critical metals production over the next two years.
Brimstone will seek private investment to replace lost government funds. The Department of Energy may announce new funding priorities favoring critical minerals. Watch for other climate tech companies to rebrand around supply chains.
The next election could reverse these trends — or entrench them. For now, survival is the only climate policy that matters.
Key Takeaways
— - Boston Metal raised $75 million to produce critical metals like niobium and tantalum, deprioritizing its green steel technology.
— - Brimstone and other climate startups are similarly pivoting to critical minerals after federal decarbonization funding was cut.
— - The strategy generates revenue but delays emissions reductions in steel and cement, which together account for 15% of global CO2.
— - The shift reflects a broader political reality: under the Trump administration, supply chain security sells better than climate action.
Source: MIT Technology Review
