(1. 江西理工大学 材料冶金化学学部，赣州 341000；
2. 虔东稀土集团股份有限公司，赣州 341000；
3. 有研科技集团有限公司，北京 100088)
摘 要: 针对碳酸钠沉淀较难获得晶型碳酸钇的问题，本文以碳酸钠为沉淀剂，通过常规沉淀探索和FBRM-PVM测试研究温度、pH、陈化、晶种等因素对碳酸钇晶型沉淀的影响，并对碳酸钇沉淀结晶过程进行深入分析。结果表明：在(80 ℃，pH 5.9~6.0)条件下，可得到沉降性能较优并具有一定结晶度的沉淀产物，此时碳酸钇的结晶过程是诱导成核→晶粒生长→Ostwald熟化的动态平衡过程；而高温搅拌陈化过程对碳酸钇的结晶没有起到正面的作用，但其剪切成核和接触成核作用可以使沉淀产物中较大颗粒逐渐转化为较小颗粒，使体系内颗粒平均粒度减小；另外，晶种的存在可以促进沉淀产物结晶转化并且加速Ostwald熟化，在晶种循环过程中，晶体生长的过程是成核→针状和片状生长→针状与片状晶体聚集成类球形水菱钇型碳酸钇晶体。实验在1次晶种循环的条件下即可得到粒度12.0 μm且分散性均匀的晶型碳酸钇。本文将为碳酸钠沉淀制备晶型碳酸钇提供理论指导。
关键字: 碳酸钠；FBRM-PVM；结晶；碳酸钇；Ostwald熟化
（1. Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. Qiandong Rare Earth Group Co., Ltd., Ganzhou 341000, China;
3. General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:In view of the difficulty in obtaining crystalline yttrium carbonate by sodium carbonate precipitation process, the sodium carbonate was used as precipitant, the effects of temperature, pH, aging and seed crystals on the crystalline precipitation of yttrium carbonate were studied by conventional precipitation experiment and FBRM-PVM, and the precipitation crystallization process of yttrium carbonate was analyzed as well. The results show that the precipitation crystallization process of yttrium carbonate is a dynamic equilibrium process of induced nucleation→crystal particles growth→Ostwald ripening at 80 ℃ and pH 5.9-6.0. Under this condition, the precipitate product with better settling properties and certain crystallinity is obtained. In addition, the high temperature stirring aging process has no positive effect on the crystallization of yttrium carbonate. But the shear nucleation and contact nucleation in the aging process can gradually transform the larger particles into smaller particles, leading to a decrease in the average particle size in the system. Moreover, seed crystals can promote crystallization transformation and accelerate Ostwald ripening. In the seed cycle process, the crystal growth process is a process of nucleation→needle-like and sheet-like growth→needle-like and sheet-like crystals aggregated into spherical crystals of tengerite type yttrium carbonate. Finally, crystalline yttrium carbonate with a particle size of 12.0 μm and uniform dispersion can be obtained under the conditions of the first cycle of seed crystals. The research in this paper will provide theoretical guidance for the preparation of crystalline yttrium carbonate by sodium carbonate precipitation.
Key words: sodium carbonate; FBRM-PVM; crystallization; yttrium carbonate; Ostwald ripening
