UK: Seratech has developed a process using olivine, a mineral abundant in Earth's mantle, to produce ‘carbon-negative’ cement. The company's method involves replacing some of the clinker with silica extracted from olivine. Magnesium sulphate derived from the olivine reacts with CO₂ to form nesquehonite, a mineral that sequesters CO₂. This method uses CO₂ captured from emissions sources or directly from the air.
Sam Draper, CEO, explained the process: “The researchers extracted these compounds by dissolving powdered olivine in sulphuric acid. After separating the silica and magnesium sulphate, they bubbled CO₂ through the magnesium slurry to form nesquehonite.”
According to Draper, replacing 35% of regular cement with this silica would yield carbon-neutral results, while a 40% substitution could achieve carbon negativity. Current building standards allow up to 55% of cement to be replaced by this material, although robust testing has yet to be conducted.
