Cement sans carbon emission!

In a study published in a recent issue of Chemical Communications, a team of researchers from Virginia’s George Washington University explain a revolutionary way to make lime cement that releases zero CO2 emissions – and costs less too. Given that cement manufacture comes next after fossil plants in emissions, this is very significant. The world consumes about 3 trillion kg of cement annually. Every 10 units of cement will release 9 units of CO2. So it is a huge problem for the increasingly unstable climate we are creating for ourselves. Of the two ways that making cement releases carbon dioxide, separating the lime from the limestone (decarbonation, or removing the carbon atom and two oxygen atoms in limestone (CaCO3) to obtain lime (CaO) with CO2) accounts for 70% of the emissions. The other 30% is because it takes a lot of heat to heat the kiln reactors, burning fossil fuels. Solar thermal power when used not just to heat the limestone – but also to help in electrolysis produces a different chemical reaction without a carbon dioxide byproduct. When electrolyzed below 800°C, the molten limestone forms lime, C, and O2. When electrolyzed above 800°C, the product is lime, CO, and ½O2. These products are useful industrial chemicals. Their carbon monoxide byproduct (in the higher temperature reaction) can be used to make fuels, purify nickel, and form plastics and other hydrocarbons. No carbon emissions. Cheap. And even better, it has wide applications. The next step would be is simply scaling up the fairly straightforward process for commercialization. Surely a welcome find,especially with the massive amount of building infrastructure poised to spring up.