Take some ultramafic rocks, micronize them, mix with water, and then mix that slurry with the flue gasses of a power plant. Then discard it. Same principle as accelerated rock weathering but many orders of magnitude faster due to higher temperature, higher surface area, and higher concentration of CO2. This could remove most of the CO2 at very low cost.
the challenge here is one of kinetics, not thermodynamics -- traditional alkanolamine point-source scrubbers react very quickly. reaction rate is a well-known bottleneck for ERW; you'll certainly get some rate enhancement due to increased temperature and CO2 concentration, but from a technoeconomic perspective such a "disposable" CO2 scrubber will require a substantially larger reaction area than a traditional amine scrubber, which means much higher CAPEX. Considering high CAPEX is already limiting for point-source scrubbers...