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,Ca^2+与配位的阴离子(O^2-,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(Q^4和Q^3)向简单(Q^2和Q^1)的转变,同时还会发生Al—O四面体[AlO4]^5-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O^2-的位置,以Al^3+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.
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 0.1745 nm,respectively.With the addition of CaF2,there is a dynamic equilibrium between Ca^2+and the coordination anions(O^2-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(Q^4 and Q^3)to simple(Q^2 and Q^1)structure and from the Al—O tetrahedral[AlO4]^5- 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 O^2- position and the network structure with the Al^3+ core has still be a tetrahedral structure,which does not cause a large-scale atomic rearrangement.
作者
张晓博
刘承军
姜茂发
ZHANG Xiao-bo;LIU Cheng-jun;JIANG Mao-fa(Key Laboratory for Ecological Metallurgy of Multimetallic Ores,Ministry of Education,Northeastern University,Shenyang 110819,China)
出处
《东北大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第4期510-515,共6页
Journal of Northeastern University(Natural Science)
基金
国家自然科学基金资助项目(51874082,51774087).
