How to extract pure carbon dioxide from sodium bicarbonate?

What are the most commonly-used methods for extracting carbon dioxide gas from an aqueous solution of sodium bicarbonate?


Several industrial "Carbon Capture" plants today are able to extract carbon dioxide from unadulterated air by passing it through an aqueous solution of sodium hydroxide ($\ce{NaOH}$) to produce an aqueous solution also containing sodium bicarbonate. There's plenty of information on the internet about this step, and it's straight forward.


What's less straight forward is how the aqueous solution with $\ce{NaHCO3}$ is later reacted to produce a pure carbon dioxide.


How can carbon dioxide gas be purified from this Direct Carbon Capture (DCC) process using an aqueous solution of sodium hydroxide ($\ce{NaOH}$)?




I could not find any verification of an industrial plant using this technology. The closest seems to be the plants in development by Carbon Engineering, which are planned to use a potassium hydroxide solution for the carbon dioxide capture step.


Their proposed process then precipitates the carbon from solution by addition of calcium hydroxide, yielding solid calcium carbonate. The $\ce{CO2}$ is liberated from the calcium carbonate by heating in a traditional calcination process such as is used in cement manufacture. This step is fueled by natural gas combustion.


In summary:


1. $\ce{CO2(g) + HO- (aq) + K+ (aq) -> HCO3- (aq) + K+ (aq)}$
2. $\ce{CaO (s) + HCO3- (aq) + K+ (aq) -> CaCO3(s) + K+ (aq) + HO- (aq)}$
3. $\ce{CaCO3 (s) + heat -> CaO(s) + CO2 (g)}$


This is described on the Carbon Engineering website [here](https://carbonengineering.com/our-technology/).


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