RE:RE:RE:RE:RE:Possibly anorthosite being discussed on Joe Rogan podcast? The majority of cement emissions (2/3) are associated with process emissions from using limestone (CaCO3) as the feedstock for the principal ingredient of cement - CaO. Limestone is not the only source of calcium from which OPC can be produced.
Brimstone has developed a process to make the same ASTM C-150 OPC using silicates instead of limestone. The calcium in silicates (the most abundant source of calcium in the crust) does not contain CO2; thus, Brimstone can make the same OPC without process emissions. Because a portion of the calcium in cement carbonates over the lifetime of the poured concrete, sequestering CO2 in the process, using non-carbonate feedstocks, when combined with decarbonized energy, could result in carbon-negative cement production.