Brimstone's silicate-rock cement process, certified to ASTM International's ordinary Portland cement standard in 2023, cuts greenhouse-gas emissions by roughly 60% versus conventional limestone-based cement — and the Oakland, California startup now says the same feedstock can yield alumina, steel, titanium and magnesium in a single refinery.

What does the expanded roadmap add?

In late 2025, Brimstone published a "Fourth Great Refinery Product" roadmap claiming its silicate-based process can deliver Portland cement, supplementary cementitious materials, smelter-grade alumina, steel, magnesium and titanium from one feedstock in one plant. CEO Cody Finke places that combined addressable market at $2.4 trillion globally.

"I think that we have one of the generational companies that's actually able to create an industrial revolution," Finke said.

The conventional limestone route releases CO2 during calcination and contributes roughly 8% of global anthropogenic CO2 — making cement the single largest industrial emitter. Brimstone sidesteps the calcination step by switching to calcium-silicate rocks, which avoids the principal chemistry-driven release.

Where does the company stand today?

Founded in 2019 in Oakland, California, Brimstone operates as a single R&D-and-pilot organization pursuing a dual mandate: cut cement emissions and onshore critical-mineral production.

• 2023: third-party ASTM certification for ordinary Portland cement (OPC). Brimstone says the certification positions its product to substitute for up to 98% of cement used worldwide.
• Late 2025: expansion of the refinery roadmap to aluminum, steel, titanium and magnesium inputs.
• Supply agreements: Amazon for cement; Century Aluminum for alumina.
• Reno, Nevada demonstration plant: construction targeted to enable a 2028 startup; first product slate limited to cement, supplementary materials and alumina.

What funding headwinds has it absorbed?

The Trump administration revoked a $189 million federal grant earmarked for the Reno facility. Finke said Brimstone continues to negotiate with the administration over restoring the funds, leaning on its critical-minerals pitch under a White House focused on supply chains dominated by China. The company has framed its story to track whichever political incentive is in season — climate funding under one administration, industrial-policy dollars under the next.

He has previously said Brimstone can move ahead with Reno without that grant or other subsidies.

What caveats apply?

Brimstone has yet to produce any of its proposed outputs at commercial scale. Skeptics quoted in industry coverage remain doubtful that a single silicate rock can yield economically viable quantities of so many materials simultaneously, given the cost and labor pressures that already squeeze US mining and refining.

The Reno plant will not stress-test the full mineral slate. Steel, titanium and magnesium sit behind cement and alumina on the timeline, pushing their commercial ramp into the 2030s. Energy, waste and cost claims for the multi-mineral route are projections; measured outputs at industrial scale do not yet exist.

For R&D managers tracking low-carbon cement and critical-mineral portfolios, the first hard numbers will arrive when the Reno line switches on in 2028 — and the operating data from that plant will decide whether the silicate-refinery thesis survives contact with a real supply chain.