Brimstone

What Brimstone does

Brimstone Energy, Inc. is a Berkeley/Oakland-based hardware cleantech startup founded in 2019 by Cody Finke and Hugo Leandri to decarbonize the production of cement and other industrial materials. The company has developed a patented co-production process branded Rock Refinery®, which refines a single, globally abundant calcium-bearing silicate rock (e.g., basalt) into multiple industrial products. The first-generation process yields Portland cement meeting ASTM C150 standards, supplementary cementitious materials (SCM) meeting ASTM C618 Class N, and smelter-grade alumina at >99% purity; future plants are expected to add steel, aluminum metal, magnesium, titanium, and other critical minerals. The four-stage process spans geology, mineral processing (comminution), hydrometallurgy, and pyrometallurgy, with the explicit aim of utilizing 100% of feed rock and eliminating limestone calcination emissions that account for roughly 60% of cement industry CO2 output.

The company is pre-revenue and operates a pilot facility at its Oakland headquarters while developing its first commercial plant near Reno, Nevada and a planned alumina plant in Oklahoma. Brimstone pursues an enterprise field sales go-to-market targeting hyperscalers and large industrial buyers; its only disclosed commercial customer is Amazon, which signed an agreement to reserve annual volumes of cement and SCM for AWS data center sites in Indiana, Japan, and Virginia. Strategic partnerships include a Memorandum of Understanding with Century Aluminum for a domestic mine-to-metal aluminum supply chain and a letter of intent with Dolese Bros. Co. for Oklahoma feedrock supply. The company has raised over $80 million in venture capital (anchored by a $55M Series A in 2022 co-led by Breakthrough Energy Ventures and DCVC), was selected for a $189M U.S. Department of Energy Industrial Demonstrations Program award that was subsequently canceled under the Trump administration, and employs 51-100 people across science, engineering, geology, policy, and business development functions.

Name

Brimstone

Legal name

Brimstone Energy, Inc.

Website

https://brimstone.com

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

51–100 employees

Short description

Brimstone is a pre-revenue hardware cleantech startup that uses a patented Rock Refinery co-production process to refine abundant silicate rocks into ASTM-compliant Portland cement, SCM, and smelter-grade alumina, targeting hyperscalers like Amazon, construction buyers, and aluminum producers.

Ownership category

akta.pro rank

Product category

Low-Carbon Industrial Materials (Cement & Critical Minerals)

NAICS

Cement Manufacturing (327310), Cement Manufacturing (32731)

SIC

Cement, Hydraulic (3241)

akta.pro primary industry

Cement Manufacturing (Portland, Blended & Specialty) (IMADAAAG)

akta.pro secondary industries

Cementitious Binders & Additives (Fly Ash, Slag, Silica Fume, Lime) (IMADAAAH), Soda Ash & Industrial Carbonates (IMAEAAAH)

Keywords

• Low-carbon cement
• Supplementary cementitious materials
• Smelter grade alumina
• Critical minerals production
• Industrial decarbonization

Headquarters

HQ city

Berkeley

HQ country

United States

HQ region

North America

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Infrastructure, Supply Chain, Operations, Marketing or Sales

Revenue model

1. Cement and SCM Sales: Brimstone produces and sells portland cement and supplementary cementitious materials (SCM) from their Rock Refinery process. They have signed commercial agreements with Amazon to reserve annual volumes of cement and SCM from their first plant near Reno, Nevada.
2. Alumina Sales: The company produces smelter grade alumina (>99% purity) as a co-product from their silicate rock processing. Alumina is the feedstock for aluminum production, addressing critical domestic supply chain needs.
3. Critical Minerals Production: Future plants will produce additional critical minerals including steel, aluminum, magnesium, titanium, and other materials. The company positions these as part of a $2.4 trillion addressable market.
4. Federal Grants and Incentives: The company was selected for a $189 million federal investment from DOE's Industrial Demonstrations Program, though this award was subsequently canceled under the Trump administration. The company continues operations despite the funding loss.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels7 records

Core offering

Brimstone manufactures and sells low-carbon Portland cement, supplementary cementitious materials (SCM), and smelter grade alumina produced via its patented Rock Refinery® co-production process, which refines a single globally abundant calcium-bearing silicate rock into multiple industrial products. The first commercial plant near Reno, Nevada will deliver cement, SCM, and alumina under multi-year commercial agreements with enterprise buyers such as Amazon.

Product overview

Brimstone is building the 'Fourth Great Refinery' using patented Rock Refinery® technology that applies co-production to cement, steel, aluminum, and critical minerals. The first-generation process produces three products: Portland Cement (meeting ASTM C150 standards), Supplementary Cementitious Materials (SCM, meeting ASTM C618 Class N), and Smelter Grade Alumina (>99% purity). Future plants will expand to include steel, aluminum metal, magnesium, titanium, and additional critical minerals—all derived from a single, globally abundant silicate rock feedstock.

Differentiator

Problem solved

Functional benefit

Products and services

• Portland Cement Conventional Portland cement produced from calcium-bearing silicate rocks that meets or exceeds ASTM C150 standards, with tricalcium silicate content greater than 60% and 28-day strength greater than 6,000 PSI. Designed to integrate into existing construction supply chains without changes to mix designs, eliminating the process emissions from limestone calcination that account for roughly 60% of cement's CO2 footprint. Sold to construction companies, concrete producers, infrastructure developers, and hyperscalers such as Amazon.
• Supplementary Cementitious Materials (SCM) Supplementary cementitious materials co-produced alongside Portland cement from residual silicates in the Rock Refinery process, meeting ASTM C618 Class N standards with r3 heat release greater than 200 J/g and 28-day strength activity index greater than 100%. Used to partially replace Portland cement in concrete to improve strength and durability while reducing carbon footprint. Sold to construction and concrete producers.
• Smelter Grade Alumina Smelter grade alumina with greater than 99% alumina content produced as a co-product of the Rock Refinery process, serving as the feedstock for aluminum production. Positions Brimstone as a potential first new domestic source of smelter grade alumina in more than 50 years, addressing U.S. supply chain security for aluminum and reducing dependence on imported bauxite. Sold to domestic aluminum producers including under the Century Aluminum MOU.

Quantifiable outcome

• Reduces cement industry energy use by under 60%
• +9 more outcomes

Named customers1 record

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Three partnerships are on record, tiered core.

• AmazoncoreStrategic or Co-development Partner · 10 December 2025Amazon signed a commercial agreement to reserve annual volumes of cement and supplementary cementitious materials from Brimstone's forthcoming plant. This is a key commercial partnership that validates Brimstone's technology and provides revenue visibility. AWS is deploying these low-carbon materials at data center sites in Indiana, Japan, and Virginia.
• Century AluminumcoreStrategic or Co-development PartnerBrimstone and Century Aluminum signed a Memorandum of Understanding to advance the first U.S. mine-to-metal aluminum supply chain. This partnership aims to spur domestic aluminum industry development using Brimstone's Rock Refinery technology.
• Dolese Bros. Co.coreStrategic or Co-development PartnerBrimstone signed a letter of intent with Dolese Bros. Co. for the feedrock essential to its alumina production process. Dolese will supply rocks from their Roosevelt quarry in Oklahoma for Brimstone's planned alumina plant.

Scale indicators9 records

Recent moves8 records

Expansion highlights6 records

Direct peers

• Sublime Systems: Direct peer developing low-carbon cement using an electrochemical process to avoid limestone-based emissions. Targets ASTM-compliant cement for the construction industry with similar decarbonization thesis as Brimstone's Rock Refinery.
• CarbonCure Technologies: Direct peer focused on reducing embodied carbon in concrete via CO2 mineralization in ready-mix concrete production. Comparable customer base (concrete producers) and decarbonization of cement-adjacent value chain.
• Prometheus Materials: Direct peer producing bio-inspired, low-carbon cementitious materials to replace traditional Portland cement. Competes in the same ASTM-spec replacement cement category targeting construction decarbonization.
• Solidia Technologies: Direct peer offering lower-carbon cement and concrete binder technology, including CO2-cured concrete. Comparable regulatory pathway (ASTM specifications) and target market (construction and infrastructure).

Emerging players

• Carbon Upcycling Technologies: Emerging player producing supplementary cementitious materials (SCMs) from industrial byproducts to displace Portland cement. Overlaps with Brimstone's SCM co-product stream and shared ASTM C618 pathway.
• Chement: Emerging player applying AI and novel chemistry to low-carbon cement production. Early-stage competitor in the same decarbonized cement category targeting hyperscaler and construction demand.

Broad incumbents

• Heidelberg Materials: One of the world's largest cement and aggregates producers. Represents the incumbent competitive baseline Brimstone must displace; also a benchmark for scale economics in cement manufacturing.
• Holcim: Global cement major with significant low-carbon product portfolio (e.g., ECOPact). Competes with Brimstone in supplying decarbonized cement and SCMs to construction and infrastructure customers.
• Cemex: Global cement and ready-mix producer with Vertua low-carbon cement line. Direct incumbent competitor in supplying reduced-carbon cement to large construction and infrastructure projects.

Others

• Energy Fuels Inc. U.S. critical minerals producer (uranium, rare earths) where Brimstone's VP of Engineering John Uhrie previously served as COO. Adjacent in the domestic critical minerals and specialty metals value chain that Brimstone's alumina and future critical-minerals products target.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/brimstoneenergy

Revenue estimate

Valuation estimate

Number of profiles

Profiles15 records

Subsidiaries1 record

Funding overview

Funding rounds5 records

Investors16 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Brimstone