The Coming of Sea Cement
The making of cement uses huge amounts of fossil-fuel-generated heat and so it is the third largest source of greenhouse gas pollution in the U.S. By one account making one ton of cement creates one ton of carbon dioxide, or more.
There are some life forms on earth that have been making cement since, well, forever, and so humans are starting to consider using their processes. Marine coral take calcium and magnesium from sea water and make carbonates out of it at normal temperatures and pressures.
A company called Calera plans to take the heat from the vent stacks of fossil-fuel power stations and use it to dry a slurry made from sea water and the carbon dioxide emissions from the stacks. The process makes chalk which is then used as a substitute for Portland cement. There are other companies on the trail of this process as well.
Since the product removes from the atmosphere and then sequesters carbon dioxide into a useable product that can then be used to create a building, the idea is that will go a long way toward reducing the global warming pollution from buildings – in the U.S. buildings account for 48 percent of that global warming pollution.
One hurdle of course are the regulators that approve structural components like concrete and the other is the people who build with things like concrete. So Calera will be first offering a blend that contains both Portland and the chalk.
Some of the flue gasses from California’s Moss Landing power plant are already turning out material for evaluation and Caltrans is interested in testing the cement from this process.
