For many decades, lithium compounds have been used in ceramic glass, enamels, adhesive, lubricant greases, and metal alloys. More recently, with advent of lithium ion batteries, lithium has been increasingly used in the rechargeable batteries of portable devices and new electric cars, because of its high energy density and expected lower cost as compared to nickel-metal hydride batteries. Brines make up more than 60% of the world’s lithium resources, from which lithium has been extracted conventionally by the removal of undesirable ions such as magnesium and calcium followed by concentration of the brine in solar evaporation ponds and the chemical precipitation of lithium compounds from the concentrated brine. Such extraction processes are slow, environmentally intrusive, and climate dependent, which has spurred a search for more efficient and environmentally friendly technologies. Among alternative approaches is selective lithium sorption by inorganic ion exchangers such as manganese oxides, namely H1.6Mn1.6O4 and H1.3Mn1.7O4, which have been studied widely over the past three decades. The complexity of the synthesis methods, loss of manganese, and the presence of impurities have prevented the commercial use of such ion exchange sorbents. In this work, we use a relatively simple co-precipitation method to produce a Li1.6Mn1.6O4 precursor with minimal impurities, as confirmed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and chemical analyses. The prepared ion sieve material, H1.6Mn1.6O4, is used to extract lithium from a sub-100 ppm Li bearing petrobrine with total dissolved solids of &gt;180,000 ppm. The results show a remarkably high distribution coefficient for Li (Kd&gt; 6,000 mg L-1) with overall Li recovery &gt;95%. In addition, the sorbent benefits from a fast kinetics owing to its high surface area, as evidenced by surface area analysis. The extracted lithium can be concentrated to more than 5,000 ppm in a mineral acid while concentrations of other major cations, such as Na and Mg, are less than 1,000 ppm. The loss of sorbent was found to be 1-2% at each cycle, indicating high chemical stability. The lithium concentrate can be polished and processed further to produce Li2CO3 or LiOH for use in batteries.

Lithium extraction from Alberta oilfield brines

2019 Fall National Meeting

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