Cement production is responsible for as much as 5% the world's annual production of CO2 and the world can't get enough of the stuff. So when Sami first wrote about Novacem, a cement substitute made from magnesium silicate, it was exciting stuff. Could this really make a dent in the 2.9 billion tonnes of cement that's made every year?
Other people also appear to think it is exciting; Novacem was named Material of the Year by Material Connexion,, the big materials consultancy, earlier this year.
Andrew Dent, Vice President of Material Connexion, said in a press release:
Concrete constitutes the greatest amount of manmade material on this planet--one that is claimed to contribute to 5% of humanity's carbon footprint," said Dr. Dent. "With a simple change of ingredient, Novacem has achieved what could be one of the single largest reductions in CO2 emissions in construction to date. This carbon negative cement reduces carbon emissions of poured concrete from 800Kg emitted per ton to 50kg absorbed per ton.
The calcium carbonate in conventional cement is pretty common- it is limestone. One question raised by a commenter in Sami's post was, where is all the magnesium silicate going to come from to make the Novacem? They explain on their website:
This production process is based on 20 years of research on the mineral carbonation of magnesium silicates. These minerals are widely dispersed with accessible worldwide reserves estimated to significantly exceed 10,000 billion tonnes.
In fact, it is pretty common; it's talc.
The Novacem product is not yet on the market, and there are some questions about it in the industry. The American Ceramic society noted after the award was announced:
According to members of the ACerS' Cement Division, magnesium-based cements are far from new and have been around since at least 1867. They are sometimes known as "Sorel cements."
While magnesium-based cements have a different chemistry than the magnesium silicate cements proposed by Novacem, some members of the division believe that they would likely be much more expensive than Portland-based cements.
One perplexing thing about this product is that there doesn't appear to be any independent research on the properties of the Novacem cement, and that would be important to examine, for example, the durability and water-resistance of Novacem's product compare with Portland-based cement. So, some caution must be exercised in regard to accepting their claims.
But the Materials Connexion people are pretty smart cookies when it comes to materials, and I doubt they would give out this award if it wasn't the real deal.