A newly identified method of producing a compound commonly used in antacids is the key to a process that provides a viable pathway for significant industrial-scale reductions in man-made greenhouse gas emissions, according to a new paper published by an 色界吧 geologist and an international team of researchers.
Published today in , the paper describes a novel low-carbon method of producing magnesium hydroxide, a highly reactive material that when combined with carbon dioxide produces magnesium carbonates, inorganic salts with a variety of commercial uses.
Magnesium hydroxide鈥檚 ability to react with CO2鈥攖he most significant of the Earth鈥檚 long-lived greenhouse gases鈥攈as long been understood, says Occidental Professor of Geology and paper co-author Christopher Oze. What has been lacking is an energy-efficient industrial process capable of producing enough magnesium hydroxide to have a substantial impact on global warming.
鈥淭he process we describe is effective, uses existing technology, produces commercially useful byproducts, is easily scalable and sequesters more carbon dioxide than it emits,鈥 Oze says. 鈥淚t鈥檚 potentially revolutionary in reducing greenhouse gas emissions.鈥
The key ingredient is olivine, a common greenish mineral found around the world. Ground into a powder, combined with hydrochloric acid and subjected to a direct electrical current, trials show that 100 metric tons of olivine would yield 35 metric tons of magnesium hydroxide and 35 metric tons of amorphous silicate鈥攁 versatile material used in the manufacture of semiconductor circuits and cement, among other uses.
Because the new process makes it possible to produce magnesium hydroxide in bulk, the compound can be shipped directly to industrial and manufacturing sites to 鈥渕ineralize鈥 the carbon dioxide being produced and keep it out of the atmosphere. 鈥淚t has much greater utility than other options being explored, such as transporting and injecting carbon dioxide into the ground,鈥 Oze says.
More importantly, this simple method may result in net negative carbon dioxide emission, even if coal-fired energy was used to power the process, the paper notes. Additionally, the acid used in the process is completely recoverable for reuse.
How large an impact could the new process have on greenhouse gases? Given the abundance of olivine around the world (it鈥檚 related to serpentinite, the official California state rock), operations on a massive scale could in theory remove and sequester all of the estimated 40 billion metric tons of man-made carbon dioxide produced last year and continue to do this for hundreds of years.
鈥淭he simplest solution would be to reduce CO2 emissions,鈥 Oze says. 鈥淏ut here鈥檚 a scalable process that鈥檚 readily available, so that if we鈥檙e collectively willing to operate at the level of magnitude needed, we are ready to sequester and use people-made CO2 at a scale once thought impossible.鈥
Oze鈥檚 co-authors are Allan Scott, Vineet Shah, Nan Yang, Aaron Marshall and Matthew Watson of the University of Canterbury, New Zealand; and Barney Shanks and Chris Cheeseman of Imperial College London, UK.
