New low-carbon cement may slash emissions
April 21, 2009
A small British company with a new variety of cement could sharply cut the carbon footprint of one of the biggest emitting industries, according to Reuters. The cement sector accounts for 5 percent of global carbon dioxide emissions. Wales-based Cenin said its cement replacement cuts carbon dioxide emissions by as much as 75 percent per tonne while the bigger players can only manage 10-20 percent. Cenin claims it can reduce CO2 emissions to just a quarter of a tonne for every tonne of cement produced and hopes to get a zero-carbon cement on the market in the near future. The cement is made from industrial by-products from the steel and energy sectors, eliminating the need to quarry raw materials and for energy-intensive kilns, co-director Martyn Popham told Reuters. On average, almost 1 tonne of carbon dioxide is emitted with every tonne of cement produced. The most efficient cement companies can reduce this to 0.8-0.9 tonnes of CO2. All the major producers are trying to reduce those emissions in order to comply with the European Union''s Emissions Trading Scheme and to cut costs in the economic slowdown. Cenin can currently only produce 75,000 tonnes per year of cement -- a small slice of the 2.75 billion tonnes produced globally. Cement is made by forming a calcium silicate product from limestone and clay minerals in a kiln, which requires very hot temperatures, releasing high levels of CO2 as it burns. Most low-carbon cements on the market are based on magnesium silicate, which takes less energy to heat. Such so-called ''novel'' cements have been criticized for being of poorer quality than Portland cement, the main material used by the construction sector. The small-scale production of cement replacements, the need for rigorous testing, and the lack of capital investment for new projects right now all hamper the chances of a low-carbon rival overtaking the leading cement product.