Empa researches carbon dioxide-negative cement
More than four billion tons worldwide each year, and rising: Cement is by far the most widely used building material and inevitably releases large quantities of the CO2 “bound” in the limestone during its production from burnt lime. Although manufacturers around the world have already significantly reduced the amount of their greenhouse gas emissions – but the more global warming progresses, the more urgently alternatives are called for.
Binders on the basis of the mineral olivine
Cements based not on limestone, aka calcium carbonate (CaCO3), but on magnesium carbonates are one source of hope. Empa experts have been investigating such binders for years on the basis of the mineral olivine, which is available in large quantities in Norway, for example. In simple terms, magnesium oxide obtained from this magnesium silicate can be processed with water and CO2 to produce cement. The bottom line is that more carbon dioxide is bound than emitted – in other words: a carbon sink.
But unlike conventional cements, whose hardening has been researched down to the tiniest detail, these materials still raise many questions. The research project “Low Carbon Magnesium-Based Binders” led by Empa expert Barbara Lothenbach should soon provide answers – thanks to an Advanced Grant from the Swiss National Science Foundation with funding of ca. 2.2 million EUR.
Further information can be found on the Empa website.