Cement is among the silent culprits of climate change, responsible for8% of global carbon emissions. What if we could produce it with zero impact, without emitting a single molecule of CO2?
Sublime Systems, a startup born from an offshoot of MIT, is transforming this rhetorical question into a tangible reality. Thanks to a revolutionary electrochemical process, the company is on the path to producing cement by not only capturing, but completely eliminating carbon emissions.
The problem of traditional concrete
Before we dive into the heart of innovation, it's critical to understand the scale of the problem. Global cement production in 2022 alone it was approximately 4,1 billion tons. Need I say anything else to make you understand the importance of a zero impact solution?
Unlike traditional methods that require fossil fuels to heat the limestone to around 1.400°C, Sublime Systems uses electrolysis. This process splits water into hydrogen and oxygen, creating a pH difference between the two electrodes. A calcium-containing mineral reacts with the acid formed at the anode, generating dissolved calcium ions that migrate to the cathode. When they reach a pH of at least 12,5, they react with the base generated at the cathode to precipitate as solid calcium hydroxide, also known as building lime.
Advantages and certifications of zero impact concrete
Sublime Systems has worked to make this technology more energy efficient and to separate the oxygen and CO2 gas flows. A work that has earned the company ASTM C1157 certification, an industrial standard based on performance requirements, which makes this cement compliant with the main American and international building codes.
The long-term goal of Sublime Systems' zero-impact concrete? Achieve cost parity with traditional Portland cement. It will take 8-10 years. In the short term, the process is slightly more expensive, but it's a gateway to a future where carbon emissions are a thing of the past.
