Adsorption Characteristics of Lithium Adsorbent Aimed at Recovery of Lithium from Geothermal Fluid

Abstract

In this study, the precursor (spinel-type lithium manganeseoxide) was synthesised using the solid-state methodfollowing Kitajou (2005), and adsorbent (spinel-typemanganese oxide) was prepared by extracting Li+ from HClsolution. To investigate the effect of synthesis conditions onlithium adsorption properties, various conditions, includingLi/Mn mole ratio (0.5, 0.75) and heating temperature(350Ž, 450Ž, 550 Ž ) were selected. As a matter ofpractical convenience, simulated geothermal fluids wereprepared at 100 mgl-1(Li), 700 mgl-1(SiO2) and 1400 mgl-1(Na), and the pH of the adsorption experiment wascontrolled at pH11 in order to prevent silica scaling duringpretreatment. XPS and XAFS analyses were used toinvestigate the adsorption of lithium by the preparedadsorbent. The largest lithium uptake was found at a Li/Mnmole ratio of 0.75 and a heating temperature of 550Ž. XPSanalysis was used to measure the surface amount of lithium.Mn K-edge XAFS analysis revealed the redox type site inthe adsorbent