λ-MnO_2担持多孔性セラミックス複合体の開発

概要

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A new granulation method was proposed for modifying microcrystalline inorganic ion-exchangers into granular shape suitable for practical applications. By this method the ion-exchanger can be supported in porous ceramics having large particle size for column operations. Spherical composite materials of λ-MnO_2 and porous ceramics, for example, were examined by X-ray powder diffraction (XRD), chemical analysis, specific surface area determination and electron probe microanalysis. The composites were produced by impregnating the pores in ceramics with lithium and manganese nitrates (Li/Mn molar ratio=0.5) and transforming the nitrates to LiMn_2O_4 by heating and then to λ-MnO_2 by acid-treatment. The optimum heating temperature was about 600℃ at which almost all the nitrates crystallized to form LiMn_2O_4 and little amounts of impurities such as α-Mn_2O_3, β-MnO_2, Mn_3O_4, etc., were present. After acid-treatment λ-MnO_2 was confirmed to be distributed uniformly in the ceramics particles. These composites had large specific surface areas up to 250 m^2・g^<-1> and adsorbed Li^+ ion selectively from a mixed alkali metal ions solution.
1992-06-01