Preparation of Silica Gels Containing Rare Earth Ions from Sodium Metasilicate and Rare Earth Chloride

Hiroaki NISHIMURA, Toshio SUGIZAKI††, Osamu MORIYA* and Toshifumi KAGEYAMA

Department of Chemistry, National Defense Academy; Hashirimizu, Yokosuka-shi 239-8686 Japan
Department of Industrial Chemistry, Faculty of Engineering, Kanto-Gakuin University; Mutsuura, Kanazawa-ku, Yokohama-shi 236-0032 Japan
†† Lintec Co. Ltd.; 5-14-42, Nishiki-cho, Warabi-shi 335-0005 Japan

Several silica gels containing rare earth ions such as neodymium, samarium, or yttrium, which differed in composition, were obtained readily from sodium metasilicate and chlorides of rare earth. The reaction was carried out at room temperature in an aqueous solution, pH value of which was adjusted to be below 1 at first step to generate monomeric silicic acid, and then the solution was neutralized to be pH=7. The spectral data of IR and UV of resulting gels suggested that rare earths dispersed well in silica phase. The TG-DTA analyses of gels showed characteristic exothermic peaks, which related with the formation of crystals of rare earth silicates. The types of crystals, obtained after calcination of gels at the temperature of exothermic peaks, were influenced apparently by the composition of rare earth and silicon.

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