With the significant CO2 emissions resulting from the production of cement from limestone, scientist Nikolaos has developed a green cement capable of absorbing CO2.
The production of concrete cement involves several steps: heating crushed limestone, clay, and sand to a temperature of 1,450 degrees Celsius using fuels such as coal and natural gas.
This process generates a substantial amount of CO2. Producing one ton of this type of cement (Portland cement) releases between 650 and 920 kg of CO2. In fact, the 2.8 billion tons of cement produced worldwide in 2009 accounted for 5% of the total CO2 emissions.
Consequently, researcher Nikolaos Vlasopoulos has experimented with a new production method aimed at eliminating emissions from the cement manufacturing process. This method is estimated to absorb about 100 kg of CO2 for every ton of cement produced. The new cement is called Novacem.
Vlasopoulos discovered the formula for Novacem while he was a student at the Royal College of London (UK). Vlasopoulos stated: “I researched various types of cement made by mixing magnesium oxide with Portland cement and realized that by adding water to the magnesium mixture without limestone (which contains a lot of CaCO3, a substance that releases CO2 when heated), the new cement achieved the desired hardness, especially when fired in gas.”
Novacem cement is of comparable quality to conventional limestone cement.
Vlasopoulos is currently determining the precise formula to ensure that Novacem products match the quality of limestone-based cement.
Another study by Calera, a company based in California (USA), aims to reduce the CO2 emissions of Portland cement. However, the new Calera cement tends to supplement Portland rather than serve as a replacement like Novacem.
Novacem faces challenges in designing an industrial-scale production process. To achieve cost parity with Portland cement, Novacem needs to be produced at a capacity of 500,000 tons per year.
The future of this environmentally friendly green cement raises many questions. Nevertheless, this new material truly has the potential to transform the current construction industry, contributing to better environmental protection.
Source: Technology Review
