New method of manufacturing cement removes CO2 from the air

A new concrete manufacturing technique extracts carbon dioxide out of the air, or directly out of industrial exhaust pipes, and turns it into synthetic limestone.

With cement manufacturing responsible for 4% to 8% of the world’s carbon dioxide emissions, this breakthrough could be a significant development in the effort to reduce greenhouse gas. Consider that the pace of construction worldwide has been robust, particularly in China, in recent years. And, cement production worldwide could grow 23% by 2050.

Portland cement is made with limestone that is quarried and then heated to high temperatures, an energy-intensive process that releases huge amounts of carbon dioxide. The new technique, which has already been demonstrated in California, could not only slow the advance of climate change, but actually help to reverse it.

The inventor was inspired by how coral transform minerals in seawater to a shell-like substance. The “low-energy mineralization” technique he developed turns captured CO2 into calcium carbonate, the material synthesized by coral.

New York City has two very large buildings dedicated to answering the 911 calls of its five boroughs. With more than 11 million emergency calls annually, it makes perfect sense. The second of these buildings, the Public Safety Answering Center II (PSAC II) is located on a nine-acre parcel of land in the Bronx. It’s an imposing 450,000 square-foot structure—a 240-foot-wide by 240-foot-tall cube. The gleaming aluminum cube risesthe equivalent of 24 stories from behind a grassy berm, projecting the unlikely impression that it might actually be floating. Like most visually striking structures, the building has drawn as much scorn as it has admiration.