东北大学学报:自然科学版 ›› 2020, Vol. 41 ›› Issue (4): 510-515.DOI: 10.12068/j.issn.1005-3026.2020.04.010

• 材料与冶金 • 上一篇    下一篇

CaF2对CaO-Al2O3-CaF2熔体结构影响的分子动力学研究

张晓博, 刘承军, 姜茂发   

  1. (东北大学 多金属共生矿生态化冶金教育部重点实验室, 辽宁 沈阳110819)
  • 收稿日期:2019-10-14 修回日期:2019-10-14 出版日期:2020-04-15 发布日期:2020-04-17
  • 通讯作者: 张晓博
  • 作者简介:张晓博(1989-),男,辽宁鞍山人,东北大学博士研究生; 刘承军(1974-),男,河南获嘉人,东北大学教授,博士生导师; 姜茂发(1955-),男,山东栖霞人,东北大学教授,博士生导师.
  • 基金资助:
    国家自然科学基金资助项目(51874082,51774087).

Molecular Dynamics Study on Effect of CaF2 on Melt Structure of CaO-Al2O3-CaF2

ZHANG Xiao-bo, LIU Cheng-jun, JIANG Mao-fa   

  1. Key Laboratory for Ecological Metallurgy of Multimetallic Ores, Ministry of Education, Northeastern University, Shenyang 110819, China.
  • Received:2019-10-14 Revised:2019-10-14 Online:2020-04-15 Published:2020-04-17
  • Contact: LIU Cheng-jun
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摘要: 采用分子动力学的方法研究了不同CaF2含量下CaO-Al2O3-CaF2三元渣系熔体结构的变化规律,包括熔渣的短程结构、中程结构和键角的变化.结果表明:Ca—F,Al—F,Ca—O,Al—O的平均键长分别为0.2345,0.1895,0.2325,0.1745nm.随着CaF2的加入,Ca2+与配位的阴离子(O2-,F-)存在动态平衡现象,总配位数维持在6~7之间.研究体系中Al—O四面体结构存在由复杂(Q4和Q3)向简单(Q2和Q1)的转变,同时还会发生Al—O四面体[AlO45-向[AlO3F]4-结构的转变,两种转变的综合作用使熔体的网络结构解聚,为CaF2改善CaO-Al2O3-CaF2熔渣的流动性提供了合理的微观解释.键角分析表明F-在体系中更多的是替换原来O2-的位置,以Al3+为核心的网络结构依然为四面体结构,没有引起大规模的原子重新排列.

关键词: CaO-Al2O3-CaF2, 熔体结构, 分子动力学, 键长, 键角

Abstract: In CaO-Al2O3-CaF2 ternary slag system, the variations of the melt structures including the short-range and medium-range structure, and bond-angle change of the slag with different CaF2 content were studied using molecular dynamics(MD)method. The results showed that the average bond lengths of Ca—F, Al—F, Ca—O and Al—O are 0.2345, 0.1895, 0.2325 and 0.1745nm,respectively. With the addition of CaF2, there is a dynamic equilibrium between Ca2+and the coordination anions(O2- and F-), and the total coordination number(CN)is maintained between 6 and 7. The Al—O tetrahedral structure in the system can be transformed from the complex(Q4 and Q3)to simple(Q2 and Q1)structure and from the Al—O tetrahedral[AlO45- to[AlO3F]4- structure, resulted to depolymerize the network structure of the melt. These observations from atomic scale well explain that the addition of CaF2 can improve the fluidity of CaO-Al2O3-CaF2 slag. The bond angle analysis indicates that the F- in the system is more likely to replace the original O2- position and the network structure with the Al3+ core has still be a tetrahedral structure, which does not cause a large-scale atomic rearrangement.

Key words: CaO-Al2O3-CaF2, melt structure, molecular dynamics, bond length, bond angle

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