Those steps (along with follow-up reactions to restore the acid or other chemicals to a usable state) obviously add up in terms of cost and energy use. Tallying up the energy to do all this using normal techniques, researchers found that you need to use twice as much energy as conventional production from limestone.
Interestingly, according to thermodynamics, the chemical transformation of basalt minerals into calcium oxide requires only about half the time as the transformation of limestone. The problem is that our techniques for facilitating chemical transformations are quite inefficient, so we can’t even come close to what is theoretically possible.
Better option?
The researchers note that there are at least some known laboratory techniques that could significantly improve our efficiency if they could be implemented on a large scale, but even if we were stuck using double the energy, producing portland cement from basalt would significantly reduce CO.2 emissions. This is because the direct liberation of CO2 Limestone is eliminated and because the entire process can run on electricity.
Assuming you use electricity from the fossil-fuel-dominated grid, they estimate that emissions will be cut by about 30 percent. Using clean electricity would eliminate most of the remaining emissions.
Obviously, there will be a trade-off cost, which usually wins out over the sustainability of the habitable environment.
But there’s another interesting aspect to this idea: Basalt’s other components also have value. Iron, magnesium and aluminum can also be separated and recovered, and the leftover silicate material can serve as an additive to portland cement instead of something like coal ash. So if these things were done together, the process could become more economically viable.
There are a lot of ifs and buts, but this relatively simple analysis can at least indicate what would need to be done to make it viable. And given that cement is one of the toughest measures in the struggle to reduce global greenhouse gas emissions, concrete solutions are welcome.
Communications Stability, 2026. DOI: 10.1038/s44458-026-00056-4 (About DOI).
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