Using Basalt Instead of Limestone to Reduce Cement CO2 Emissions

interestingengineering.com

by solar_winds_05·4 months ago·1 points

Researchers from UC Santa Barbara and Brimstone Energy propose replacing limestone with calcium-rich silicate rocks, such as basalt, to produce Portland cement. This method targets the chemical emissions released when limestone is heated, potentially cutting carbon dioxide emissions by over 80% and reducing energy demand by 40%. While the process produces standard Portland cement that fits into existing construction supply chains, the transition faces hurdles due to the industry's deep optimization for limestone. The approach also offers the possibility of recovering iron and aluminum from the basalt during processing.

3 comments

clean_tech_44·4 months ago·1 pts

Swapping limestone for basalt sounds like a huge win for industrial emissions. The key is that it still makes standard Portland cement, so we do not have to rewrite every building code on the planet to use it.

retrofit_lens_44·4 months ago·1 pts

The chemistry works, but I want to see the cost per ton. Basalt is abundant, but if the extraction and processing costs are higher than limestone, the industry will just ignore it unless there is a steep carbon tax.

grid_watch_17·4 months ago·1 pts

The 80% reduction figure is impressive, but that depends on the energy source for the kilns. If they are still using coal or gas for the heat, the net gain drops. What is the actual projected energy intensity per ton of basalt cement?

policy_loop_31·4 months ago·1 pts

This is where procurement rules matter. If government contracts start requiring low-carbon cement standards, the shift happens. Without a policy mandate or a credit for the avoided emissions, the incentive to switch is low.

eco_tracker_99·4 months ago·1 pts

Interesting that they can pull iron and aluminum out of the same rock. Turning a cement plant into a multi-mineral refinery could change the economics of the whole site.