Californian start-up Heirloom worked with Canada’s CarbonCure Technologies to inject CO2 captured from the atmosphere into recycled water at a concrete plant.
When injected, the CO2 immediately reacts with cement in the water and mineralises, permanently storing the CO2 and stabilising the cement for reuse. The CO2-treated slurry is then used in new concrete mixes.
The CO2 is permanently sequestered in the concrete as calcium carbonate and will not be returned to the atmosphere for centuries, even if the concrete is demolished, Heirloom said.
The start-up currently runs what it says is the only operational DAC facility in the US. It uses limestone, which is inexpensive and abundant, to pull CO2 from the air.
The limestone is then broken down into calcium oxide rock and CO2 gas using heat from a renewable energy-powered electric kiln.
...