高等学校化学学报 ›› 2003, Vol. 24 ›› Issue (9): 1652.

• 论文 • 上一篇    下一篇

过饱和铝酸钠溶液中氢氧化铝自发成核动力学规律的研究

李洁, 陈启元, 尹周澜   

  1. 中南大学化学化工学院, 长沙 410083
  • 收稿日期:2002-08-26 出版日期:2003-09-24 发布日期:2003-09-24
  • 通讯作者: 李洁(1965年出生),女,博士,主要从事冶金物理化学和材料化学研究.E-mail:phychemlijie@hotmail.com E-mail:phychemlijie@hotmail.com
  • 基金资助:

    国家自然科学基金(批准号:59874031);国家重大基础发展规划研究项目(批准号:G199906492-3)

Studies on the Kinetics of Unseeded Nucleation of Aluminum Trihydroxide from Supersaturated Sodium Aluminate Solutions

LI Jie, CHEN Qi-Yuan, YIN Zhou-Lan   

  1. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
  • Received:2002-08-26 Online:2003-09-24 Published:2003-09-24

摘要: 用电导法和吸光光度法首次对苛性比相同的不同浓度过饱和铝酸钠溶液自发分解过程进行了实时跟踪研究,获得铝酸钠溶解氢氧化铝自发成核动力学方程,探索了H2O和Na+对氢氧化铝自发成核过程的影响.结果表明,过饱和铝酸钠溶液分解为氢氧化铝属化学反应控制过程;H2O参与了溶液分解过程控制步骤的反应;K+和Na+等阳离子参与了溶液的重构,但对溶液分解的控制步骤影响不大.

关键词: 铝酸钠溶液, 氢氧化铝, 自发成核, 结晶动力学

Abstract: Under isothermal batch crystallization condition, unseeded nucleation of Al(OH)3crystals from supersaturated caustic aluminate solution was studied by in situ conductivity and absorbance measurements. The nucleation kinetics of Al(OH)3crystals were obtained and the influence of H2O and Na+on the unseeded nucleation were investigated. The experimental results indicate that, when the molar ratio of Na2O to Al2O3is fixed in Na2O-Al2O3-H2O system. The crystallization of Gibbsite display two kinds of nucleation mechanism with variation of H2O content. When Na2O in the crystallization system is substituted by K2O, the induction period of the crystallization is prolonged, but the active energy and the reaction order are all found to be independent of the alkali ion. It can be concluded that, the nucleation of Al(OH)3crystals in supersaturated alminate solution is a chemical reaction controlled process, H2O and Na+take part in the reconstruction of alminate ions though they are not present in the overall-reaction of Al(OH)3crystallization. H2Ois related to the key procedure of the decomposition of supersaturated sodium alminate solution. Yet, Na+has little effects on the controlling-step.

Key words: Sodium aluminate solutions, Al(OH)3, Unseeded nucleation, Crystallization kinetic

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