Brimstone

What Brimstone does

Brimstone is an Oakland, California-based chemical manufacturing company founded in 2019 that decarbonizes cement and allied heavy-industry materials via a patented co-production platform called Rock Refinery®. Its core process refines a single, globally abundant calcium-bearing silicate rock into multiple industrial products — portland cement, supplementary cementitious materials (SCM), and smelter grade alumina — by combining mineral processing (comminution), hydrometallurgy, and pyrometallurgy. Because the feedstock contains no embedded CO2 and replaces limestone, the process eliminates the roughly 60% of cement emissions attributable to limestone calcination; Brimstone cement has achieved ASTM C150 compliance (greater than 60% tricalcium silicate, greater than 6,000 PSI 28-day strength) and SCM has met ASTM C618 Class N requirements, while the company targets greater than 99% alumina purity for aluminum feedstock.

The company is pre-revenue, with first commercial manufacturing facilities planned in Reno, Nevada (cement and SCM) and Oklahoma (alumina, sourced from the Dolese Bros. Co. Roosevelt quarry) — the latter being the first new U.S. alumina plant in over 50 years. Brimstone's go-to-market is direct enterprise sales to industrial off-takers, with Amazon signed as anchor commercial customer for portland cement volumes (July 2025) and Century Aluminum as an MOU partner for the U.S. mine-to-metal aluminum supply chain (June 2025). Management has expanded with materials-industry veteran James 'Tim' Rens as CFO, Lottie Rezneck as COO, and metallurgical veteran John Uhrie as VP of Engineering; the company has approximately $244 million in disclosed capital across a $55 million Series A led by DCVC (April 2022) and a $189 million U.S. Department of Energy Industrial Demonstrations Program award (2024, reported subsequently terminated). In December 2025, Brimstone announced it had gone public as 'Fourth Great Refinery' with an expanded roadmap into steel, magnesium, titanium, and other critical minerals, positioning the platform to address products accounting for more than 95% of all mined materials on Earth.

Name

Brimstone

Legal name

Brimstone Energy, Inc.

Website

https://brimstone.com

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

11–50 employees

Short description

Brimstone is an Oakland-based chemical manufacturing company developing a patented Rock Refinery® co-production process that refines a single silicate rock into ASTM-compliant portland cement, supplementary cementitious materials, and smelter grade alumina, targeting decarbonization of cement and domestic production of critical minerals for construction, aluminum, and defense customers.

Ownership category

akta.pro rank

Product category

Industrial Materials Manufacturing

NAICS

Cement Manufacturing (327310), Cement Manufacturing (32731), Nonmetallic Mineral Product Manufacturing (327), Ground or Treated Mineral and Earth Manufacturing (327992)

SIC

Cement, Hydraulic (3241), Primary Smelting & Refining Of Nonferrous Metals (3330), Industrial Inorganic Chemicals (2810), Mining & Quarrying Of Nonmetallic Minerals (No Fuels) (1400)

akta.pro primary industry

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

akta.pro secondary industries

Alumina Refining (Bayer Process) (IMAKACAB), Concentrate & Product Handling (Agglomeration, Pelletizing, Briquetting, Drying) (IMAKALAG)

Keywords

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

Headquarters

HQ city

Oakland

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, Infrastructure, Supply Chain, Personnel, Operations

Revenue model

1. Portland Cement Sales: Sales of portland cement produced through the Rock Refinery process. First commercial plant coming online with Amazon as anchor customer. Targets construction industry supply chains.
2. Supplementary Cementitious Materials (SCM): Co-produced SCM sold alongside cement to concrete producers, improving strength and durability while reducing carbon footprint.
3. Smelter Grade Alumina: Alumina feedstock for aluminum production. First new domestic source of smelter grade alumina in over 50 years. Partnership with Century Aluminum for mine-to-metal supply chain.
4. Future Products (Steel, Aluminum, Magnesium, Titanium): Future plants will expand product slate to include steel, aluminum, magnesium, titanium, and additional critical minerals.

Go-to-market motion1 record

Distribution channels2 records

Marketing channels5 records

Core offering

Brimstone manufactures industrial materials, primarily portland cement, supplementary cementitious materials (SCM), and smelter grade alumina, through its patented Rock Refinery® co-production process. The process refines a single, globally abundant calcium-bearing silicate rock into multiple high-value industrial products via mineral processing, hydrometallurgy, and pyrometallurgy. Future plant generations will expand the slate to steel, aluminum, magnesium, titanium, and other critical minerals.

Product overview

Brimstone operates as a co-production industrial materials company built around its Rock Refinery® platform. The platform produces four distinct products: Portland Cement (meeting ASTM C150 standards), Supplementary Cementitious Materials (SCM, meeting ASTM C618 Class N), and Smelter Grade Alumina (>99% purity). These products are co-produced from a single, globally abundant silicate rock feedstock through a patented integrated process. Future plant expansions will extend the product slate to include steel, aluminum, magnesium, titanium, and additional critical minerals. The first-generation process produces cement, alumina, and SCM from one rock in one location, with subsequent generations adding more products to the portfolio.

Differentiator

Problem solved

Functional benefit

Brands

• Rock Refinery®: Patented co-production process that refines a single, globally abundant rock into cement, supplementary cementitious materials (SCM), alumina, steel, aluminum, magnesium, titanium, and other critical minerals.

Products and services

• Rock Refinery® Co-Production Platform

Quantifiable outcome

• Eliminates 60% of cement production process emissions by using carbon-free silicate rocks instead of limestone
• +3 more outcomes

Named customers2 records

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Three partnerships are on record, tiered flagship and core.

• AmazonflagshipStrategic or Co-development Partner · 28 July 2025Amazon signed a commercial agreement to reserve volumes of Brimstone's portland cement from its forthcoming plant. This collaboration advances lower-carbon cement supply for Amazon's construction needs. Amazon is the anchor customer for Brimstone's first commercial plant.
• Dolese Bros. Co.coreStrategic or Co-development Partner · 30 June 2025Brimstone signed a letter of intent with Oklahoma-based Dolese Bros. Co. for the feedrock essential to its process. The partnership will supply rocks from Roosevelt quarry for the first new U.S. alumina plant in over 50 years.
• Century AluminumflagshipStrategic or Co-development Partner · 24 June 2025Brimstone 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 industry by combining Brimstone's alumina production with Century's aluminum manufacturing capabilities.

Scale indicators7 records

Recent moves7 records

Expansion highlights6 records

Direct peers

• Solidia Technologies: Direct competitor developing lower-carbon cement and concrete binder technologies. Comparable to Brimstone in targeting ASTM/industry-standard drop-in cement substitutes with reduced CO2 footprint, though Solidia focuses on a CO2-cured binder rather than feedstock substitution.
• Century Aluminum: Direct strategic partner and peer in domestic aluminum supply chain, currently the U.S. primary aluminum smelter counterpart to Brimstone's planned alumina plant. Highly comparable as the downstream offtaker for Brimstone's alumina and as a domestic critical-minerals counterpart.
• CarbonCure Technologies: Direct peer in the low-carbon cement/concrete space, injecting captured CO2 into ready-mix concrete. Highly comparable customer base (ready-mix producers and construction buyers) and similar decarbonization thesis, though CarbonCure is downstream of cement rather than a cement manufacturer.
• Sublime Systems: Direct competitor producing low-carbon cement via an electrochemical process that eliminates limestone calcination emissions. Closest technical analogue to Brimstone's feedstock-substitution approach, targeting ASTM-compliant supplementary and replacement cements.

Broad incumbents

• Alcoa: Largest U.S. aluminum producer and incumbent alumina refiner (bauxite-based). Comparable to Brimstone's alumina line as a domestic alumina/aluminum competitor, and illustrates the entrenched supply chain Brimstone is attempting to bypass with silicate-rock feedstock.
• Cemex: Global incumbent in cement, ready-mix concrete, and aggregates with active vertical carbon strategy (Vertua lower-carbon products). Comparable in targeting construction-industry decarbonization at scale, and a likely competitor for Brimstone's Amazon-adjacent construction customers.
• Holcim: One of the world's largest cement and aggregates incumbents, with growing investments in lower-carbon cement and calcined-clay cements. Provides the competitive scale benchmark Brimstone must beat on price and the strategic benchmark on decarbonization roadmap.
• Heidelberg Materials: Major global cement, aggregates, and ready-mix incumbent with the industry's most ambitious CCUS roadmap (evoZero carbon-captured cement). Comparable as a large-scale lower-carbon cement supplier that could compete directly with Brimstone on Amazon and similar enterprise buyers.

Emerging players

• Carbon Upcycling Technologies: Emerging player producing supplementary cementitious materials (SCMs) from industrial byproducts and CO2. Overlaps with Brimstone on the SCM product line and on supplying cement/concrete decarbonization, but focuses on waste-stream feedstocks rather than silicate rock.
• Terra CO2: Emerging low-carbon cementitious materials producer targeting SCMs and cement replacement. Compares to Brimstone on the SCM/co-product side of the cement decarbonization value chain, though Terra CO2 uses industrial waste feedstocks rather than silicate rock.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/brimstoneenergy
• Xx.com/brimstoneenergy

Revenue estimate

Valuation estimate

Number of profiles

Profiles15 records

Funding overview

Funding rounds

Investors

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