CaO-Al2O3-SiO2熔渣结构和热导率的分子动力学模拟

利用分子动力学模拟研究CaO-Al₂O₃-SiO₂三元熔渣的微观结构和热导率。针对六组不同Al₂O₃含量的熔渣,基于BMH势函数分析了径向分布函数、键长、键角分布函数、氧类型和微结构单元Qⁿ等微观结构信息。结果表明硅和铝在熔渣中以四面体网络结构存在,硅氧四面体较铝氧四面体更为稳定。随着铝含量增加,熔体中的键长和四面体中心角无明显变化,Al-O-Al和Si-O-Al键角逐渐减小;网络中的桥氧(BO)和三配位氧(TO)含量增加,Q³和Q⁴含量增多,在高铝区出现较多的五配位铝(Al^V)。采用Muller-Plathe方法计算了熔渣的热导率,随着铝替代硅原子,网络的聚合程度增加,强化了熔体的热输运能力,热导率呈现增大趋势。

Molecular Dynamics Simulation of Microstructure and Thermal Conductivity of CaO-Al2O3-SiO2 Slag

The microstructure and thermal conductivity of CaO-Al₂O₃-SiO₂ ternary slag was studied using molecular dynamics simulation.For six groups of slag with different Al₂O₃ content,the radial distribution functions(RDF),bond length,bond angle distribution functions,oxygen type and tetrahedral units Qn were analyzed based on BMH potential function.The silicon and aluminum as network former exist in tetrahedral network structure in the slag,and the silicon-oxygen tetrahedron is more stable.With the increasing of Al₂O₃ content,the bond length and tetrahedral center angle in the slag almost unchanged while the bond angles of Al-O-Al and Si-O-Al decrease.It was found that the percentages of bridge oxygen(BO)and tricluster oxygen(TO)increases.The content of Q³ and Q⁴ also increases with more five-coordinated aluminum(Al^V)appearing in the high aluminum region.The Muller-Plathe method was used to calculate the thermal conductivity of the slag.As aluminum replaced silicon atoms,the degree of polymerization of the network increased,which strengthened the thermal transport capacity of the molten slag,and the thermal conductivity showed an increasing trend.