MIT researchers find a way to make cement greener

A group of researchers at MIT have announced that they have found a way to eliminate carbon emissions from cement production. The scientists say that it's well known that the production of cement, which is the leading construction material in the world, is a significant source of greenhouse gas emissions. The team says that cement production alone accounts for about 8% of all greenhouse gas emissions.

To put a finer point on it, MIT researchers say that if cement production were a country, it would be the world's third-largest emitter. The researchers have come up with a new way to manufacture the material that could eliminate greenhouse gas emissions from the cement manufacturing process and possibly make other useful products in the process.

Currently, about a kilogram of carbon dioxide is released for every kilogram of cement made today. Portland cement is the most widely used standard variety. It's created by grinding limestone and cooking it with sand and clay at higher heat. The heat is typically made by burning coal. Researchers say that their process eliminates or drastically reduces greenhouse gasses created from the burning coal and released when heating the limestone.

The new process uses an electrolyzer where a battery is hooked to two electrodes in water to produce bubbles of oxygen from one electrode, and bubbles of hydrogen from the other, as the electricity splits the water molecules. The new process dissolves the pulverized limestone in the acid at one electrode a with carbon dioxide released and lime precipitating out as a solid at the other electrode. The lime, or calcium hydroxide, can then be processed in another step to produce the cement.

The carbon dioxide is produced in a pure, concentrated stream and can be sequestered easily. Once sequestered, it can be used to create products like a liquid fuel to replace gas or used in oil recovery and carbonated beverages. The result is production with no carbon dioxide released into the environment.