The Cement that Eats Carbon Dioxide

Cement, a vast source of planet-warming carbon dioxide (making the 2bn tonnes of cement used globally every year pumps out 5% of the world’s CO2 emissions – more than the entire aviation industry), could be transformed into a means of stripping the greenhouse gas from the atmosphere, thanks to an innovation from British engineers.

Making traditional cement results in greenhouse gas emissions from two sources: it requires intense heat, and so a lot of energy to heat up the ovens that cook the raw material, such as limestone. That then releases further CO2 as it burns. But, until now, no one has found a large-scale way to tackle this fundamental problem. Novacem’s cement, based on magnesium silicates, not only requires much less heating, it also absorbs large amounts of CO2 as it hardens, making it carbon negative.

According to Novacem, its product can absorb, over its lifecycle, around 0.6 tonnes of CO2 per tonne of cement. This compares to carbon emissions of about 0.4 tonnes per of standard cement. The company is confident the material will be strong enough for use in buildings but acknowledged that getting licenses to use it will take several years of testing.

Original article: Alok Jha. The Guardian. 31 December 2008. Read more…