New cement breakthrough from Germany?

New cement breakthrough from Germany?
29 December 2010

Cement producers have been able to chip away at energy use over the years by using more efficient equipment and operations. But a process that could dramatically reduce the amount of energy it takes to produce cement or the amount of CO2 cement puts out could be a breakthrough in terms of reducing greenhouse gas emissions. At Germany’s Karlsruhe Institute of Technology, chemist Peter Stemmermann says his lab has an approach that will do both (reports National Geographic).

Called Celitement, it’s a sort of an imitation cement that is heated to about 570ºF (300ºC) a fifth of the temperature needed by regular cement—a huge energy savings. By starting with a mixture lower in calcium and using different kinds of silicon components than ordinary cement, and by adding water earlier in the process, among other things, Stemmermann’s ersatz cement alters the chemical reaction and slashes the amount of CO2 unleashed. 

The finished product can be used in standard-issue construction machinery. “You just have to mill it a little bit, and it reacts like ordinary cement,” Stemmermann says. “Everybody wants a cement that can be used with regular machines.”

Stemmermann says affordability is, indeed, Celitement’s biggest challenge. “We need less energy, but to start with, we will be more expensive,” he says. “If you just compete with ordinary Portland cement, you have to be cheaper—and that’s just not possible.”

For now, Stemmermann and his partners are pushing Celitement, which seems to be more resistant to corrosion than ordinary cement, as a solution to specific needs. One application, he says, might be wastewater treatment plants, where harsh chemicals are used in concrete-lined lagoons full of waste. Stemmermann thinks Celitement would last longer, saving money in the long run even if it cost more to start with. “If you come up with a cement which is more durable, nobody has a problem to pay more,” he says. “We need to have some additional value.”

So far, Celitement has been produced on a very small scale in Stemmermann’s Karlsruhe lab, a few pounds at a time. But investors are impressed enough to fund a small pilot plant scheduled to open in 2011, and the Germany’s Schwenk Zement is working with the researchers to open a plant that can churn out 66,000t of Celitement a year by 2014. If the method takes off, it could make a significant dent in the construction industry’s contribution to greenhouse gases.
Published under Cement News