CARBON-NEGATIVE CEMENT: A TRIBOLOGICAL SOLUTION FOR LIMESTONE DECARBONATION, SILICATION AND CARBON UTILIZATION

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The CILANTRO technology offers a groundbreaking solution to reducing the carbon footprint associated with traditional cement production. CILANTRO introduces non-thermal, Direct Tribochemical Hydrogenolysis (DTCH) of calcium carbonate with silica yielding no CO2 emission and producing solid (CaO)nSiO2 (where n = 1,2,3) - the essential component of Ordinary Portland Cement. This innovative approach significantly deviates from current practices by bypassing the high-temperature steps of the conventional production process, which are fueled by fossil fuels, such as limestone calcination and clinkerization. It also co-produce CO which is the resource of synthetic fuels and offers another benefit to reducing carbon footprint. The key DTCH reaction design utilizes free-radical intermediates generated by rubbing/shearing of limestone and sand without heating, followed by in situ reduction of carbonate with H2. To suppress the competitive reactions which can lead to undesired minor CO2 emission DTCH procedure and parameters will be analyzed by laboratory measurements and computer simulations at different levels. To carry out the DTCH at scale, CILANTRO aims to design a new well-controlled tribo-reactor having a mechanical principle similar to the existing comminution mills in cement plants. It is expected that CILANTRO technology can be easily scaled up and employed as a new asset. By using electricity and H2 from renewable sources, the whole cement production process can be carbon-neutral. Given the natural/accelerated carbonation of concrete fabricated from CILANTRO binders the cement can achieve significant net CO2 sink over the concrete lifecycle. CILANTRO is compatible with other approaches and processes addressed within the portfolio such as combination with supplementary cementitious materials, carbonation curing, and increasing binder efficiency.