利用废弃矿井封存二氧化碳

An abandoned mineral mine near Stanford University is providing geoscientists new insights on how to permanently entomb（埋葬） greenhouse gas emissions in the Earth. For two years, a team of Stanford researchers has been trying to unravel a geological mystery at the Red Mountain mine about 70 miles east of the campus. The abandoned mine contains some of the world's largest veins of pure magnesium carbonate, or magnesite -- a chalky mineral made of carbon dioxide (CO2) and magnesium. How the magnesite veins formed millions of years ago has long been a puzzle.

Now the Stanford team has proposed a solution. Their findings could lead to a novel technique for converting CO2, a potent greenhouse gas, into solid magnesite. The results will be presented at the 2013 fall meeting of the American Geophysical Union (AGU) in San Francisco.

"Conventional geological storage involves capturing CO2 from industrial smokestacks（烟囱） and injecting it as a fluid into the subsurface," said Kate Maher, an assistant professor of geological and environmental sciences at Stanford. "But there is concern that the carbon dioxide would eventually leak back into the atmosphere. Our idea is to permanently lock up the CO2 by converting it into a stable mineral."

Power plants and other industries are responsible for more than 60 percent of global CO2 emissions, according to the International Energy Agency . Sequestering the CO2 in magnesite deposits would prevent the gas from entering the atmosphere and warming the planet, Maher explained.