BRIMSTONE IS BUILDING THE FOURTH GREAT REFINERY.
ONE PROCESS. LOW WASTE. MULTIPLE MARKETS.
Co-production has shaped the biggest industrial shifts in history—from oil refining to fertilizer to metals processing.
Brimstone is now applying this model to the world's largest material markets. The Rock Refinery® produces multiple critical industrial materials from a single, globally abundant rock—building an efficient, cost-effective new era of heavy industry.
OUR FIRST THREE PRODUCTS
The Brimstone Process produces critical minerals and commodities accounting for more than 95% of all mined materials on Earth.
The first plant will produce portland cement, smelter grade alumina, and supplementary cementitious materials (SCM)—three of the most widely used industrial materials. Future plants will expand the product slate to include steel, aluminum, magnesium, titanium, and beyond.
PORTLAND CEMENT
Brimstone cement meets or exceeds ASTM C150 standards for portland cement, the most widely used cement in the world.
ASTM C150
TRICALCIUM SILICATE CONTENT
>60%
28 DAY STRENGTH
>6000 PSI
SUPPLEMENTARY CEMENTITIOUS MATERIALS
Brimstone SCM meets the physical and chemical requirements of ASTM C618 Class N.
ASTM C618 CLASS N
r3 heat release
>200 J/g
28 DAY STRENGTH ACTIVITY INDEX
>100%
SMELTER GRADE ALUMINA
Under development
Industry specifications
ALUMINA CONTENT
>99%
What is portland cement?
Portland cement has been the foundation of modern construction for over 200 years, comprising virtually the entire U.S. cement market. As the key binder in concrete, it’s critical to building infrastructure—from skyscrapers and bridges to roads and homes. Its durability, versatility, and affordability have made it the trusted material for engineers worldwide.
Over time, other cements have been developed and marketed as alternatives to portland cement. But these alternative cements produce concrete with different properties, such as setting times, expansive behavior, and strength development. They are used primarily for niche applications and have not gained broad traction as a portland cement replacement.
The problem? Portland cement production comes at a massive climate cost, accounting for 7.5% of global CO₂ emissions—three times that of aviation.
Brimstone is changing that. Our team developed an efficient, economical and sustainable process to deliver conventional portland cement that meets existing industry standards (ASTM C150). We’re not altering the material—just how it’s made—to seamlessly integrate into the production process, scale efficiently, and build a better future.
What is SCM?
SCM is added to concrete to partially replace portland cement, improving its strength and durability while reducing its carbon footprint.
Common SCMs include ground granulated blast furnace slag and fly ash—materials typically sourced from coal-fired steel production or electricity generation.
With the switch from blast furnaces to electric arc furnaces and the decline of coal-fired power plants, conventionally sourced SCM is becoming increasingly scarce.
However, Brimstone has developed a solution. Brimstone produces an SCM that meets existing standards and comes from a co-production process with ordinary portland cement—enabling these materials to reliably and seamlessly integrate into the construction supply chain.
One rock. One process. Multiple essential industrial ingredients.
What is alumina?
Alumina is the feedstock used to produce aluminum—a critical material and the world’s second-most consumed metal. It plays a vital role across industries, including defense, aerospace, transportation, construction, technology, consumer goods, and clean energy.
The U.S. depends heavily on imports throughout the aluminum supply chain—producing less than 17% of the primary aluminum it consumes, only about 9% of the alumina required to make that aluminum, and 0% of the mined ore (bauxite) needed to produce that alumina. The U.S. has only one operating alumina refinery today.
Unlike conventional alumina production, which depends on bauxite (an ore typically sourced from tropical and subtropical regions overseas), Brimstone’s feedrocks are widely available, reducing the dependence on the limited number of countries with economic bauxite reserves. This unlocks the ability to produce alumina efficiently and sustainably, virtually anywhere.
The Rock Refinery® could be the first new domestic source of smelter grade alumina in more than 50 years.
OUR PROCESS
The Brimstone process produces multiple essential industrial materials. Our first-generation process below produces three products: portland cement, SCM and smelter grade alumina.
Cement, SCM and alumina are typically made through separate processes and sourced from different locations. Our rock contains all the necessary elements to produce all three industry-standard products from one process and in one location. Our process is deeply decarbonized across a range of energy scenarios.
step 1
GEOLOGY
Portland cement is made from calcium and silica. Traditionally, this process involves heating limestone, which releases CO₂—about 60% of cement’s emissions come from the heating of limestone. The Brimstone process starts with a different feed rock: calcium-bearing silicate rocks, which contain no embedded CO₂. Brimstone obtains the feed rocks from simple quarry operations.
step 2
MINERAL PROCESSING
A key part of the process is mineral processing, or comminution. During the comminution step, Brimstone crushes the feed rock to the desired particle size.
step 3
HYDROMETALLURGY
Next, the Brimstone team mixes the calcium silicate rock with chemicals to extract calcium and aluminum. These elements are separated to extract calcium compounds for cement and aluminum compounds for alumina. The residual silicates are then dried and processed to make SCM.
step 4
PYROMETALLURGY
A rotary kiln heats the calcium compounds to produce clinker, which is then milled with gypsum to produce portland cement. Brimstone separately processes the extracted aluminum compounds to produce alumina.
DIVE DEEPER
We’re transforming heavy industry with breakthrough science, and we're hiring. Learn about careers at Brimstone.
We’re partnering with developers, corporations and innovators on next-generation industrial materials, so we can build more efficiently, economically and sustainably.
ONE PROCESS. LOW WASTE. MULTIPLE MARKETS.
Co-production has shaped the biggest industrial shifts in history—from oil refining to fertilizer to metals processing.
Brimstone is now applying this model to the world's largest material markets. The Rock Refinery® produces multiple critical industrial materials from a single, globally abundant rock—building an efficient, cost-effective new era of heavy industry.
OUR FIRST THREE PRODUCTS
The Brimstone Process produces critical minerals and commodities accounting for more than 95% of all mined materials on Earth.
Our product roadmap includes portland cement, smelter grade alumina, supplementary cementitious materials (SCM), steel, aluminum, magnesium, titanium, and more. The first plant will debut the first-generation process, which will produce cement, alumina, and SCM (read more about this process below). Future plants will deliver additional products.