Thermal process to transform silicate minerals into alkaline solids for carbon removal

Stanford researchers in the Kanan Lab have developed a scalable method for achieving verifiable, safe, and permanent carbon removal at relatively low energy demand.

This work demonstrates that calcium oxide can react with diverse magnesium silicates to form calcium silicate and magnesium oxide. When exposed to air and moisture, these products convert to dissolved bicarbonate ions or carbonate minerals, sequestering CO2. By cycling this chemistry with calcium carbonate calcination, a new carbon dioxide removal process emerges where the calcium/magnesium products capture CO2 from air as stable (bi)carbonates while process emissions are sequestered.

Studies shows this could provide efficient CO2 removal using less than half the energy of leading direct air capture technologies. If applied to soils, the calcium silicate/magnesium oxide materials could provide agronomic value as a silicon fertilizer. The process unlocks magnesium silicates as an abundant resource for safe, permanent atmospheric carbon removal with co-benefits.

Stage of Development