Last month saw the announcement of a pioneering project: a company called Heirloom Carbon Technologies will capture carbon dioxide from the ambient air and then hand it off to a company called CarbonCure Technologies, which will inject the CO2 into concrete made by a company called Central Concrete. It will mark the first time ever that carbon from the air is permanently sequestered in concrete.Heirloom, with runs the US’s only operating direct air capture (DAC) facility, does not use the familiar capture technique that involves giant fans. Instead, it binds carbon to exposed rock and then cooks it out using electric kilns — and then binds more carbon to the rock, in a circular process. It claims the capture is cheaper and more efficient than previous methods.CarbonCure injects the CO2 into a concrete mixer, where it mineralizes, becoming permanently captured even if the building using the concrete is demolished. In the process, it strengthens the mix, requiring less cement and cutting costs.Direct air capture (DAC) has faced a great deal of skepticism, and concrete has the reputation as one of the worst carbon offenders, so this project — one of the first that can fairly be called carbon removal — could go a long way toward convincing investors that the former can help the latter change its ways, with a technology that is, at least some day, commercializable.I talked with Heirloom CEO Shashank Samala and CarbonCure CEO Robert Niven about their respective processes, how they work together, and what the project says about the future of carbon removal. Get full access to Volts at www.volts.wtf/subscribe