Al_(2)O_(3)对熔融态高炉渣结构与黏度影响的分子动力学模拟  

Molecular dynamics simulation of effect of Al_(2)O_(3) on structure and viscosity of molten blast furnace slag

作　　者：曹亚然 徐博 王铮铮 田晨 龙跃 CAO Yaran;XU Bo;WANG Zhengzheng;TIAN Chen;LONG Yue(College of Metallurgy and Energy,North China University of Technology,Tangshan 063210,Hebei,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《烧结球团》2022年第6期57-65,共9页Sintering and Pelletizing

基　　金：国家自然科学基金区域创新发展联合基金资助项目(U20A20271);河北省自然科学基金资助项目(E2020209209)。

摘　　要：Al_(2)O_(3)过高会引起高炉渣性能(尤其是流动性)的恶化,给高炉正常冶炼带来一系列不良的影响。为了研究Al_(2)O_(3)对熔融态高炉渣结构与性能的影响规律,本文利用分子动力学方法系统研究不同Al_(2)O_(3)质量分数下熔融态高炉渣的微观结构及黏度变化情况,基于BMH势函数分析径向分布函数(RDF)、配位数(CN)、键长、键角分布函数和均方位移(MSD)等微观结构信息。结果表明:熔体中Si和Al主要以[SiO_(4)]^(4-)和[AlO_(4)]^(5-)四面体的形式存在,随着Al质量分数的增加,Si-O和Al-O的配位数逐渐向4靠近,预示着[SiO_(4)]^(4-)和[AlO_(4)]^(5-)四面体的结构变得越来越稳定;熔体中Si-O、Al-O、Ti-O、Mg-O、Ca-O键的键长分别为1.59、1.77、2.35、2.29、2.31?,各键的键长随着Al_(2)O_(3)质量分数的增加并无明显变化;O-Si-O、O-Al-O、Si-O-Si和Si-O-Al的键角分别在109°、104°、145°、135°附近波动,其中O-Si-O键角分布曲线的峰高和峰宽保持最为稳定,再次表明高炉渣熔体内[SiO_(4)]^(4-)四面体结构基本不受Al质量分数的影响,是高炉渣网络结构中最为稳定的骨架结构。桥氧Si-O-Si质量分数降低,Al-O-Si和Al-O-Al质量分数升高,非桥氧Si-O-Ca、Al-O-Ca、Si-O-Ti、Si-O-Mg、Al-O-Ti、Al-O-Mg质量分数呈下降趋势;利用均方位移(MSD)、爱因斯坦方程及黏度之间的关系函数,计算不同Al_(2)O_(3)质量分数下熔体内各原子的自扩散系数和黏度,结果表明:随着Al_(2)O_(3)质量分数的增加各原子的自扩散系数逐渐减小,黏度逐渐增大,当Al_(2)O_(3)质量分数超过16%时,黏度增加变得缓慢。Excessive Al_(2)O_(3) will worsen the performance of blast furnace slag(especially fluidity)and bring a series of adverse effects on normal smelting of blast furnace.In order to study the influence of Al_(2)O_(3) on the structure and properties of molten blast furnace slag,molecular dynamics method is used to systematically study the microstructure and viscosity changes of molten blast furnace slag with different Al_(2)O_(3) mass fractions,and the microstructure informations such as radial distribution function(RDF),coordination number(CN),bond length,bond angle distribution function and mean square displacement(MSD) are analyzed based on BMH potential function.The results show that Si and Al in the melt mainly exist in the form of [SiO_(4)]^(4-) and [AlO_(4)]^(5-) tetrahedrons.With the increase of Al mass fraction,the coordination number values of Si-O and Al-O gradually approach 4,which indicates that the structures of [SiO_(4)]^(4-) and [AlO_(4)]^(5-) tetrahedrons become more and more stable.The bond lengths of Si-O,Al-O,Ti-O,Mg-O and Ca-O in the melt are 1.59,1.77,2.35,2.29 and 2.31 ?,respectively,and the bond lengths of each bond have no obvious change with the increase of Al_(2)O_(3) mass fraction.The bond angles of O-Si-O,O-Al-O,Si-O-Si and Si-O-Al fluctuate around 109°,104°,145°,135°,respectively,and the peak height and peak width of the O-Si-O bond angle distribution curve remain the most stable,which onceagain indicates that the [SiO_(4)]^(4-) tetrahedral structure in the blast furnace slag melt is basically not affected by Al mass fraction,and it is the most stable skeleton structure in the blast furnace slag network structure.The mass fraction of bridging oxygen Si-O-Si decreases,the mass fraction of Al-O-Si and Al-O-Al increases,and the mass fraction of non-bridging oxygen Si-O-Ca,Al-O-Ca,Si-O-Ti,Si-O-Mg,Al-O-Ti and Al-O-Mg decreases.The self-diffusion coefficient and viscosity of each atom in the melt with different Al_(2)O_(3) mass fraction are calculated by using the relation function between

关 键 词：高炉渣 分子动力学 桥氧 四面体 黏度 

分 类 号：X757[环境科学与工程—环境工程] TF09[冶金工程—冶金物理化学]