Stay Cool

Many prominent scientists warn that increasing levels of carbon dioxide in the atmosphere could cause global warming. With governments debating restrictions on carbon dioxide emissions, technologies for carbon dioxide disposal may have a bright future. Scientists have experimented with a variety of disposal methods, such as recycling carbon dioxide to beverage manufactures, or injecting it beneath the ocean floor, but none of these solutions lock up CO₂ permanently. That’s the advantage of an idea proposed by three scientists at the Los Alamos National Laboratory in New Mexico.

Particle physicists Klaus Lackner and Christoper Wendt, and materials scientist Daryl Butt, knew that CO₂ forms a stable compound with magnesium silicate, but it takes centuries for the reaction to occur in nature. Once it does, however, the carbon dioxide is trapped for millions of years. To speed up the process, the researchers dissolved magnesium silicate in hydrochloric acid, producing magnesium hydroxide, a compound that forms a long lasting bond with CO₂ in about half an hour.

The Loa Alamos team hasn’t yet demonstrated the idea is economically feasible on a large scale. But the researchers envision a process in which magnesium silicate would be strip-mined and trucked to carbon dioxide disposal plants which would be constructed near where carbon dioxide is produced. At the disposal plant, the magnesium hydroxide would be soaked in hydrochloric acid to form magnesium hydroxide, which readily bonds with carbon dioxide under pressure to form magnesium carbonate. The magnesium carbonate would then be transported back to the strip mine and used as fill.

"There would be thousands of these [CO₂ disposal] plants," says Lackner, if they are to have significant effect on atmospheric carbon dioxide levels. – Sharon Parmet