Crystallization and Morphological Evolution of Yttrium Carbonate
来源期刊：Journal of Rare Earths2006年第S2期
论文作者：李永绣 黄婷 黎敏 周雪珍 罗军明 何小彬
文章页码：64 - 68
摘 要：The crystallization and morphological evolution of yttrium carbonate when aging at 50 ℃ after its precipitation by ammonium bicarbonate with feed molar ratio NH4HCO3∶YCl3=2 were investigated by means of XRD, SEM and pH situ-determination. It was found that pH value and deposit volume of the solution all deceased in a two-step manner during aging. Correspondingly, the spherulitic needle-aggregate yttrium carbonate formed initially was transformed into 2-D flake and 3-D regulate grain particles. However, X-ray patterns of all the crystalline yttrium carbonates are identified with the structure of tengerite Y2（CO3）3·2H2O. These facts demonstrate that the crystallization of yttrium carbonate follows Oswald′s rule of stages that the final stable morphology of crystalline yttrium carbonate is transformed from 1-D to 2-D, and then to 3-D by two or more steps through the mechanism of dissolution-recrystallization. A fast crystallization method of yttrium carbonate with large particle size was proposed.
李永绣，黄婷，黎敏，周雪珍，罗军明，何小彬
摘 要：The crystallization and morphological evolution of yttrium carbonate when aging at 50 ℃ after its precipitation by ammonium bicarbonate with feed molar ratio NH4HCO3∶YCl3=2 were investigated by means of XRD, SEM and pH situ-determination. It was found that pH value and deposit volume of the solution all deceased in a two-step manner during aging. Correspondingly, the spherulitic needle-aggregate yttrium carbonate formed initially was transformed into 2-D flake and 3-D regulate grain particles. However, X-ray patterns of all the crystalline yttrium carbonates are identified with the structure of tengerite Y2（CO3）3·2H2O. These facts demonstrate that the crystallization of yttrium carbonate follows Oswald′s rule of stages that the final stable morphology of crystalline yttrium carbonate is transformed from 1-D to 2-D, and then to 3-D by two or more steps through the mechanism of dissolution-recrystallization. A fast crystallization method of yttrium carbonate with large particle size was proposed.
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