LITHIUM EXTRACTION FROM WAIRAKEI GEOTHERMAL WATERS.

Lithium is the most likely constituent of geothermal waters to be worth extracting, and the well-known coprecipitation method with aluminum hydroxide has been investigated for Wairakei waters. In field experiments optimum conditions were at pH equals 10. At 30 degree C lithium recoveries were over 95%, and at 64 degree C over 50%. Laboratory experiments showed that, after coprecipitation, aluminum hydroxide gel filters easily and the lithium can be rapidly desorbed from the gel at 60 degree C. A simple adsorption-desorption continuous process may be possible which would recycle about 95% of the aluminum used. This process is limited by the geothermal water in the aluminum hydroxide gel.