Lithium from oilfield brines, so-called “petro-lithium”, is an expensive and technically challenging undertaking. Proponents underestimate the difficulty in extracting lithium from spent oilfields. Some of these wells are up to four kilometers deep, the brine needs to be pumped and trucked to a storage site, then the lithium has to be separated from all the other impurities which could include uranium, thorium, magnesium and potash. It's neither an easy nor a cheap process and no company has yet been able to do it on a commercial scale.d
