Sorption of lithium from a geothermal brine by pelletized mixed aluminum-lithium hydrous oxides

An inorganic ion exchanger was evaluated by the Bureau of Mines for recovering lithium from geothermal brines. The ion exchanger or sorbent was mixed hydrous oxide of aluminum and lithium that had been dried at 100 C. The dried precipitate was pelletized with a sodium silicate binder to improve flow rates in sorption tests. The sorbent was loaded to 2 mg Li/g of pellets and sorption from the solution was independent of the concentrations of Ca, Fe, Mn, and Zn. Manganese and zinc were sorbed by the pellets but did not suppress lithium sorption. Lithium was desorbed with water, but none of the washing solutions investigated removed entrained brine without stripping lithium. The complex nature of the sorption mechanisms is discussed.