Abstract
Four kinds of spinel-type manganese oxides were prepared by the acid treatment of lithiummanganates which were obtained with different methods and conditions. Their bulk and surfaceproperties were investigated by chemical, X-ray, DTA-TG analyses, and nitrogen adsorption-desorptionat-196°C. Although their X-ray diffraction patterns resembled each other, the DTA-TGcurves and surface characteristics varied widely depending on the preparation conditions.
The adsorptive properties of the manganese oxide adsorbents for lithium ions were investigatedin the brine of Daquidham salt lakes and in NH4Cl-NH3(aq) buffer solutions containing LiCl. Lithium uptake from the brine varied between 1.4 and 25.9 mg/g depending on the preparationconditions. The lithium uptake by the adsorbent was well correlated with its weight loss between 100 and 300°C in the TG curve. This correlation suggests that the lithium ion adsorption takesplace not on the redox-type sites but on the Li-specific ion-exchange sites of the spinel-type manganese oxide.
