15th April 2024
Green cement? Part 1
Cement is made by heating limestone and clay together at very high temperatures. The clay and limestone is converted to a dried out material called clinker, whilst at the same time releasing large amounts of carbon dioxide. The clinker when ground to a powder is what we know as cement.
The production of cement has a very high carbon footprint arising from a) the energy needed to roast the clay and limestone which invariably comes from fossil fuels, and b) the carbon dioxide released during manufacture. Each tonne of cement produces up to 622kg carbon dioxide.
Cement is widely used in large quantities across the globe in the construction of buildings, roads, drains and various other types of infrastructure. CO2 emissions from cement account for 7% of all global emissions – 1605 tonnes per year. Here in the UK cement produces about 4b tonnes CO2.
https://www.bbc.co.uk/news/science-environment-46455844
The Green Tau 