Preparation of Silica Gels Containing Rare Earth lons from Sdium Metasilicate and Rare Earth Chloride

摘要

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 w~ adjusted to be below 1 at first step to generate monomeric silicic acid, and then the solution was to be pH =7. The spectral data of IR and UV of resulting gels suggested that rare earths dispersed weE, silica phase. The TG—DTA analyses of gels showed characteristic exothermic peaks, which re~at.ed with the formation of crystals of rare earth silicates. The types of crystals, obtained after calcination d~ the temperature of exothermic peaks, were influenced apparently by the composition of rare eaulka.i siboon