(1. 江西理工大學(xué) 材料冶金化學(xué)學(xué)部，贛州 341000；
2. 虔東稀土集團(tuán)股份有限公司，贛州 341000；
3. 有研科技集團(tuán)有限公司，北京 100088)
摘 要: 針對(duì)碳酸鈉沉淀較難獲得晶型碳酸釔的問題，本文以碳酸鈉為沉淀劑，通過(guò)常規(guī)沉淀探索和FBRM-PVM測(cè)試研究溫度、pH、陳化、晶種等因素對(duì)碳酸釔晶型沉淀的影響，并對(duì)碳酸釔沉淀結(jié)晶過(guò)程進(jìn)行深入分析。結(jié)果表明：在(80 ℃，pH 5.9~6.0)條件下，可得到沉降性能較優(yōu)并具有一定結(jié)晶度的沉淀產(chǎn)物，此時(shí)碳酸釔的結(jié)晶過(guò)程是誘導(dǎo)成核→晶粒生長(zhǎng)→Ostwald熟化的動(dòng)態(tài)平衡過(guò)程；而高溫?cái)嚢桕惢^(guò)程對(duì)碳酸釔的結(jié)晶沒有起到正面的作用，但其剪切成核和接觸成核作用可以使沉淀產(chǎn)物中較大顆粒逐漸轉(zhuǎn)化為較小顆粒，使體系內(nèi)顆粒平均粒度減小；另外，晶種的存在可以促進(jìn)沉淀產(chǎn)物結(jié)晶轉(zhuǎn)化并且加速Ostwald熟化，在晶種循環(huán)過(guò)程中，晶體生長(zhǎng)的過(guò)程是成核→針狀和片狀生長(zhǎng)→針狀與片狀晶體聚集成類球形水菱釔型碳酸釔晶體。實(shí)驗(yàn)在1次晶種循環(huán)的條件下即可得到粒度12.0 μm且分散性均勻的晶型碳酸釔。本文將為碳酸鈉沉淀制備晶型碳酸釔提供理論指導(dǎo)。
關(guān)鍵字: 碳酸鈉；FBRM-PVM；結(jié)晶；碳酸釔；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
