Researches On Preparation Of Y-Al Based Ceramic Pigments By Co-precipitation Method And Decomposition Comparison Of Typical Rare Earth Minerals

Rare earths have important use in the ceramic pigments because of its special physical and chemical properties. The ceramic colorants doped with rare earths have attracted much interest in the recent years. In this paper, the preparation and the testing methods of the chroma of the ceramic colorants doped with yttrium have been studied considering the rich yttrium resource in country. Furthermore, the economic indicator of the resolving technology of the rare earth mines have been also analyzed and compared. The details have been described as below:The technology of Y-Al-Cr colorant prepared by the co-precipitation method have obtained with different precipitants by regular design experimental conditions method. The resolving temperature of van system have been measured by DTA. The physical properties such as phase and light reflect properties was studied by the method of XRD, reflect spectra analysis and particle size distribution test. The results show that the color of the samples were turned from French grey to heavy gray, which was also compared with that obtained by the solid state method. Additives experiment show that suitable additives can decrease the synthesis temperature of the colorants while improve the chroma of the samples. The red colorants with good chroma can be derived in the 1300℃with the calcium carbonate and rluorol as additives, whose weights were 4.3% and 3.1% of the total weight of the yttria and alumina, respectively.Comparing the conditional reflect spectra testing method with modern digital testing technology, the results shows that the reflectivity or the variation of the chroma can be well demonstrated by 1st rank derivative of the conditional reflect spectra testing method, while the experimental results can be conveniently and rapidly expressed by the modern digital testing technology.The samples in which the Y was substituted with other rare earth (La, Ce, Pr, Sm, Eu, Gd, Dy, Ho, Er, Yb et.al) in Y-Al-Cr system were also synthesized. The results show that the colorants doped with Dy, Ho, and Yb have good chroma. The influences of the Fe, Co, Mn and Cu on the color of the colorant have been also discussed.In the end, the economic benefit of the resolving technology of the common rare earth mines has been analyzed.