A New Source of Lithium For Batteries: Geothermal Power Plants
September 30, 2011 Leave a comment
From Scientific American: In a double-dose of environmental goodness, a new technology allows lithium (the key component of lithium-ion batteries that power portable electronics and most electric cars) to be collected as a byproduct of geothermal power production.
Geothermal electricity is generated by pumping up hot water from deep underground and using the heat to make gas turn turbines and power a generator. This can be done by a) pumping up steam in the first place, and making that turn the turbines, b) pumping up hot, high-pressure water and then turning it into steam by decreasing its pressure, or c) pumping up hot water and transferring its heat to another fluid with a lower boiling point, like butane or pentane, turning those into gas. This last solution means that the water doesn’t have to be quite as hot to get the job done.
In any of these cases, the used water is then pumped back down to the source, maintaining the underground reservoir. The new development in question, from Lawrence Livermore National Laboratory, adds an extra step: before injecting the water back underground, they use a novel extraction process to remove its lithium content. This water (or brine, meaning it carries dissolved salts) has had a long time to dissolve the minerals around it underground, making it a rich source of seemingly everything:
The Salton Sea brine contains a host of other elements, and Simbol hopes to extend the extraction process to manganese and zinc—also used in batteries and metal alloys—as well as potassium, which is a vital nutrient and fertilizer, among other applications. “This brine has got half the periodic table in it and that’s a good news–bad news situation,” Erceg says, noting that cesium, rubidium and silver might also be produced the same way. The company is also exploring options for using the process’s waste silica—more commonly known as sand—in the cement industry.
This is clearly a step up from lithium mining; extracting lithium from a renewable, constant source that’s brought right to you. If this new technology simultaneously encourages the development of alternative energy and feasible electric cars, I’ll consider it a big win all-around.