The invention teaches a practical method of recovering CO2 from a mixture of gases, and sequestering the captured CO2 from the
atmosphere for geologic time as
calcium carbonate and provides a CO2
scrubber for carbon capture and sequestration. CO2 from the production of
calcium oxide is geologically sequestered. A
calcium hydroxide solution is produced from the environmentally responsibly-produced
calcium oxide. The CO2
scrubber incorporates an aqueous froth to maximize liquid-to-gas surface area and time-of-contact between gaseous CO2 and the
calcium hydroxide solution. The CO2
scrubber decreases the temperature of the liquid and the mixed gases, increases
ambient pressure on the bubbles and
vapor pressure inside the bubbles, diffuses the gas through intercellular walls from relative smaller bubbles with relative high
vapor pressure into relative larger bubbles with relative low
vapor pressure, and decreases the mean-free-paths of the CO2 molecules inside the bubbles, in order to increase
solubility of CO2 and the rate of
dissolution of gaseous CO2 from a mixture of gases into the
calcium hydroxide solution.The CO2 scrubber recovers gaseous CO2 directly from the
atmosphere, from post-
combustion flue gas, or from industrial processes that release CO2 as a result of process. CO2 reacts with calcium ions and
hydroxide ions in solution forming insoluble
calcium carbonate precipitates. The
calcium carbonate precipitates are separated from solution, and sold to recover at least a portion of the cost of CCS.