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The cement industry, vital for global construction, faces pressure over its large carbon footprint. Cement production traditionally uses limestone, and heating it releases significant carbon dioxide. This process is responsible for about 8% of global CO2 emissions, making cuts essential to meet climate targets.
Why Cement Production is a Climate Challenge
The standard process heats limestone above 1,500 degrees Celsius. This chemical reaction releases CO2 directly from calcium carbonate. Each ton of cement produced emits around 500 kilograms of CO2, creating a significant environmental barrier.
Basalt: A Greener Alternative
Scientists propose switching to carbon-free, calcium-rich silicate rocks like basalt. A study in Communications Sustainability found ample global basalt reserves to supply cement production for hundreds of thousands of years using current methods.
Cuts in Emissions and Energy Use
Basalt offers significant benefits. Cement made from this rock could need up to 60% less energy than limestone-based cement. CO2 emissions per ton could drop from over 600 kilograms (using limestone and natural gas) to just 43-59 kilograms with basalt. This change could sharply reduce the industry's climate impact. Even using current fossil fuels, CO2 emissions could fall by over 25%.
Economic Benefits and Quicker Rollout
The research also points to potential cost savings from lower energy use. Basalt rocks can contain valuable metals, which could be recovered as by-products. Unlike some new "green cement" types needing extensive testing, this basalt method uses current technology. This could speed up adoption in the construction sector, avoiding long development and demonstration periods. The end product is standard Portland cement, compatible with existing uses. The study suggests a significant shift, offering a practical way to decarbonize a key global industry.