Carbon
negative from rock to city block

The Brimstone Process™ is a breakthrough in cement production, making carbon negative portland cement with carbon-free calcium silicate rock instead of limestone. Cement made with The Brimstone Process™ is chemically and physically identical to conventional portland cement, with the same quality and performance builders have trusted for over 150 years. Simply put, our process will turn cement, one of the most intractable climate problems, into a carbon negative climate solution. It all starts with a new kind of rock.

 01   One Rock
 

Cement is conventionally made from carbon-heavy limestone which releases CO2 when processed. These process emissions are responsible for up to 60% of cement's overall emissions.

 

We make cement from carbon-free calcium silicate rock, eliminating these process emissions from the start. Calcium silicate is a hundred times more abundant than limestone.

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 02   One Process

Our process produces two core products used in concrete: Portland cement clinker and supplementary cementitious materials (SCM). Today, clinker and SCM are produced from different processes and sourced from different locations. Our rock contains all the minerals necessary to make both cement and SCM from one process, one location.

 03   One Big Impact for the Planet
 

Our process removes CO2 from the air, resulting in truly carbon negative cement. How? In addition to the calcium, silicon, iron and aluminum used to make cement, our rock also contains magnesium. We use this magnesium to permanently remove atmospheric CO2.

Minimalist Staircase

Let's build

 

We are working with industry leaders and other key partners to scale and maximize our impact on climate change. Interested in joining the fight? We’d love to talk.