化工进展 ›› 2020, Vol. 39 ›› Issue (3): 1101-1107.DOI: 10.16085/j.issn.1000-6613.2019-1009

• 材料科学与技术 • 上一篇    下一篇

粒度对氢氧化铝低温相变动力学的影响

范伟东1,2(),李旺兴1(),韩东战1,2,郑纯辉2   

  1. 1.中南大学冶金与环境学院,湖南 长沙 410083
    2.中国铝业郑州有色金属研究院有限公司,河南 郑州 450041
  • 收稿日期:2019-06-24 出版日期:2020-03-05 发布日期:2020-04-03
  • 通讯作者: 李旺兴
  • 作者简介:范伟东(1977—),男,博士研究生,研究方向为精细氧化铝。E-mail:22543647@qq.com

Influence of particle size on kinetics of low temperature phase transformation of aluminum hydroxide

Weidong FAN1,2(),Wangxing LI1(),Dongzhan HAN1,2,Chunhui ZHENG2   

  1. 1.School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China
    2.Zhengzhou Non-ferrous Metals Research Institute Corporation Limited of Aluminum Corporation of China limited, Zhengzhou 450041, Henan, China
  • Received:2019-06-24 Online:2020-03-05 Published:2020-04-03
  • Contact: Wangxing LI

摘要:

利用综合热分析仪分析技术、激光粒度分析、扫描电镜和X射线衍射研究了粒度对氢氧化铝在低温相变转化成勃姆石过程的影响,并采用Kissinger方程、Ozawa方程和Crane方程进行了不同粒度的氢氧化铝在低温相变过程的动力学参数计算。结果表明:普通砂状氢氧化铝在相变过程有2个较为明显的吸热峰,将砂状氢氧化铝研磨至中位径D50在12μm左右时,相变过程仍然有2个明显的吸热峰;当氢氧化铝中位径D50在1μm左右的氢氧化铝,相变过程则只有1个吸热峰。根据Kissinger方程和Ozawa方程计算结果,随着粒度的降低,其相变活化能也相应的降低,说明降低氢氧化铝粒径,有利于勃姆石的制备。根据XRD图谱显示,低温煅烧后,样品的主要物相为勃姆石,此外还含有少量的三水铝石,粒径越细,煅烧后样品中勃姆石含量越高。

关键词: 氢氧化铝, 勃姆石, 相变动力学, 粒度

Abstract:

The function of particle size to the transformation of aluminum hydroxide to boehmite under low temperature conditions were investigated by comprehensive thermal analysis technique, laser particle size analyzer (LPSA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Meanwhile, Kissinger equation, Ozawa equation and Crane equation were applied for analysis of the influence of particle size on phase transformation of aluminum hydroxide. The results showed that two clear endothermic peaks were appeared in the course of phase transformation of normal sandy aluminum hydroxide and grinded sandy aluminum hydroxide, and only one endothermic peak was appeared in the course of phase transformation of micron aluminum hydroxide which medium diameter was about 1μm. According to the results of calculations with Kissinger equation and Ozawa equation, the activation energy of phase transformation of aluminum hydroxide was decreased along with the decrease of particle size, which showed that a lower particle size was benefit for phase transformation from aluminum hydroxide to boehmite. The XRD of aluminum hydroxide after calcinations showed that the primary crystal phase was boehmite and the secondary crystal phase was gibbsite. The content of boehmite was increased with the decrease of particle size.

Key words: aluminum hydroxide, boehmite, phase transformation kinetics, particle size

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