What could be better than building concrete structures without creating more CO2? How about this: a new form of cement that actually absorbs carbon dioxide rather than being a primary source of its man-made emissions.
Consider this: 1 out of 20 units of carbon released by human activity into the atmosphere comes directly from concrete – this does not even take into account other construction-related activities, such as on-site vehicles or other building materials.
So how does an age-old, nearly-universal building material move from being destructive to the environment to being constructive for pollution? “By replacing the calcium carbonates used in cement formulation with magnesium silicates, and by using a low-temperature production process that runs on biomass fuels … developing a new class of cement that offers performance and cost parity with ordinary Portland Cement, but with a negative carbon footprint.”
““Our cement is based on magnesium oxide (MgO) and hydrated magnesium carbonates. Our production process uses accelerated carbonation of magnesium silicates under elevated levels of temperature and pressure (i.e. 180oC/150bar). The carbonates produced are heated at low temperatures (700oC) to produce MgO, with the CO2 generated being recycled back in the process. The use of magnesium silicates eliminates the CO2 emissions from raw materials processing. In addition, the low temperatures required allow use of fuels with low energy content or carbon intensity (i.e. biomass), thus further reducing carbon emissions. Additionally, production of the carbonates absorbs CO2; they are produced by carbonating part of the manufactured MgO using atmospheric/industrial CO2. Overall, the production process to make 1 ton of Novacem cement absorbs up to 100 kg more CO2 than it emits, making it a carbon negative product.”
Novacem’s Carbon Negative Cement is two steps in the right direction, simultaneously displacing a carbon-intensive building block and substituting it with something that goes beyond simply doing no harm. As for awards: “Novacem is a World Economic Forum Technology Pioneer for 2011 and features on MIT Technology Review’s list of the ten most important emerging technologies for 2010. It is also on the Global Cleantech 100, is a Wall Street Journal Technology Innovation winner and a Bloomberg New Energy Pioneer for 2010.”