基于分子动力学研究熔渣的微观结构特性
Research on the Microstructure Characteristics of Molten Slag Based on Molecular Dynamics

冶金熔炼过程中的非铁组元在升温条件下的粒子迁移及分子尺度的相互作用直接影响着微观粒子之间的反应进程，进而影响着熔渣宏观物理化学性质。本文利用分子动力学计算分析CaO-SiO₂-MgO(-Al₂O₃₎熔渣体系的高温结构，并通过计算偏径向分布函数分析Ca-O、Mg-O、Si-O及Al-O的键长。结果表明：相较于Si-O和Al-O来说，Ca-O和Mg-O空间扩散速度较快，活跃能力更强。键长关系为Ca-O > Mg-O > Al-O > Si-O，且由于Ca-O、Mg-O的键长较大，反应势垒较小，使得Ca-O、Mg-O高温反应性好；CaO-SiO₂-MgO体系中加入Al₂O₃时，因[AlO₄]^5？微观网络结构和反应特性与[SiO₄]^4？相近，可以部分地替代[SiO₄]^4？与碱性氧化物发生反应，导致Si-O的键长变短。通过红外光谱对熔渣结构进行了表征，红外光谱分析在一定程度上验证了分子动力学模拟结果的准确性。在CaO-SiO₂-MgO熔渣体系加入Al₂O₃会加快微观粒子的扩散速率，以此改变了多元体系内部化学反应的进行。
The metallurgy reaction process was influenced directly by the particle migration and the interaction with the molecule scale of the non-ferrum component in the smelting process when the temperature was increased. In this paper, molecular dynamics calculations are used to analyze the high temperature structure of the CaO-SiO₂-MgO (-Al₂O₃) slag system, and the bond lengths of Ca-O, Mg-O, Si-O and Al-O are analyzed by calculating the partial radial distribution function. The results show that compared with Si-O and Al-O, Ca-O and Mg-O have a faster spatial diffusion rate and a stronger active capacity. The bond length relationship is Ca-O > Mg-O > Al-O > Si-O, and because the bond length of Ca-O and Mg-O is larger, the reaction barrier is smaller, which makes Ca-O and Mg-O have good reactivity at high temperature. When Al₂O₃ is added to the system, because [AlO₄]^5？ microscopic network structure and reaction characteristics are similar to [SiO₄]^4？, it can partially replace [SiO₄]^4？ and react with alkaline oxides, resulting in shorter Si-O bond length. The structure of molten slag was characterized by infrared spectroscopy, which verified the accuracy of molecular dynamics simulation results to a certain extent. Adding Al₂O₃ to the CaO-SiO₂-MgO slag system will accelerate the diffusion rate of microscopic particles and promote the progress of chemical reactions in the multi-element system.