by A game-changing cement technology developed by Sublime Cement has the potential to revolutionize the construction industry by offering a zero-carbon alternative to traditional cement production. Unlike conventional cement manufacturing processes that rely on fossil-fueled furnaces, Sublime Cement utilizes room-temperature electrolyzers and a variety of zero-carbon input materials to produce cement that meets industry performance standards.
The development of a cost-competitive zero-carbon cement alternative could prove to be highly lucrative in the face of growing decarbonization mandates and carbon taxes. As governments worldwide increasingly prioritize sustainable development, the demand for low-carbon and carbon-capturing concrete alternatives is on the rise. MIT spinout Sublime Systems is attracting attention with its electrochemical approach to cement-making, which eliminates carbon emissions entirely rather than aiming for net-zero emissions or carbon sequestration.
In traditional cement manufacturing, limestone is heated to extremely high temperatures using fossil fuels, resulting in significant carbon emissions. However, because limestone contains around 50% carbon dioxide, capturing these emissions is challenging due to their mixture with flue gases. Sublime Cement’s method, on the other hand, relies on electrolysis to achieve a true zero-carbon process.
Co-founders Leah Ellis, Ph.D., and Dr. Yet-Ming Chiang explain the process in detail in a Medium post. In summary, water is split using electrolysis, generating hydrogen and oxygen gases and creating a pH gradient between the two electrodes. A mineral containing calcium reacts with the acid formed at the anode, producing dissolved calcium ions that migrate towards the cathode. When the pH reaches at least 12.5, the calcium ions react with the base generated at the cathode, resulting in the formation of solid calcium hydroxide, also known as builder’s lime.
This lime acts as a drop-in replacement in traditional cement manufacturing. The Sublime team has optimized the process to be more energy-efficient, eliminate hydrogen production, separate the oxygen and CO2 gas streams, enable continuous extraction of lime from the reactor, and utilize standard electrolysis equipment.
The flexibility of the process allows for the use of various feedstocks. When low-grade limestone is economically viable, it can be used as a feedstock. While the process does produce CO2 emissions, they are in a pure, cold state, making them easier to capture and store. Furthermore, the overall energy consumption and emissions created during Sublime Cement’s process are significantly lower compared to conventional cement production.
For a true zero-carbon cement alternative, the process can extract pure calcium from impurities found in silica, magnesium, iron, or aluminum, thereby refining these materials into higher-grade products. The noteworthy aspect of this approach is that it functions at room temperature, eliminating the need for combustion furnaces or electric heating.
Sublime Cement declares itself as the only fossil-fuel-free, scalable, drop-in replacement for traditional cement in concrete. By combining environmental sustainability with performance, Sublime Cement has the potential to disrupt the cement industry and contribute to global efforts in mitigating climate change.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
