Sucking Up the CO2?

Limestone is a common sedimentary rock. It may, with US government funding, eventually provide a partial answer to climate change. California's Heirloom project is the USA's first Direct Air Capture (DAC) plant (https://www.theguardian.com/environment/2023/nov/19/carbon-dioxide-direct-air-capture). DAC takes limestone and heats it to very high temperatures, presumably using 'green' energy. The heat breaks the rock down into carbon dioxide and calcium oxide. Rather than allowing the carbon dioxide to escape, it's trapped in new concrete that can then be used in building projects. The remaining calcium oxide powder is subsequently placed in plastic trays. These trays are stacked in impressive towers and occasionally sprayed with water. Carbon dioxide naturally binds to the powder. This 'greenhouse gas' can be driven off to be again stored in concrete. The process can be repeated, removing carbon dioxide from the atmosphere. DAC effectiveness, of course, depends on the 'greenhouse gas' remaining in the constructed buildings for extended periods. Most of our world's concrete is currently produced by heating limestone and simply allowing carbon dioxide to escape into the atmosphere. It's a major source of anthropogenic 'greenhouse gas' release. Hopefully, all concrete manufacturers can be encouraged to capture their carbon dioxide?