Molecular Dynamics Study of the Structural Properties of Calcium Aluminosilicate Slags with Varying Al2O3/SiO2 Ratios
Molecular Dynamics Study of the Structural Properties of Calcium Aluminosilicate Slags with Varying Al2O3/SiO2 Ratios
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DOI：
10.2355/isijinternational.52.342
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发表时间：
2012-03
影响因子：
1.8
通讯作者：
K. Zheng;Zuotai Zhang;Feihua Yang;S. Sridhar
中科院分区：
文献类型：
--
作者：
K. Zheng;Zuotai Zhang;Feihua Yang;S. Sridhar
通过分子动力学模拟研究了在CaO含量固定的情况下，不同Al2O3/SiO2比例的铝硅酸盐钙渣的结构变化。在实际应用中，研究结果与高溶铝钢连铸过程中化学成分变化引起的渣结构显著变化有关。随着Al2O3/SiO2摩尔比的增加，Q4四面体（含4个桥接氧的四面体）增加，NBOs（非桥接氧）减少，表明形成了更聚合的网络。随着Al2O3/SiO2摩尔比的增加，氧三聚体浓度急剧增加，达到24%，Al （CNAl-O）的配位数也从CAS1的4.02增加到CAS11的4.11，表明[AlO4]取代[SiO4]后，熔渣中出现了高配位数的Al。nbo倾向于与Si配位，而Al倾向于在更聚合的环境中作为网络中间相定位。计算了Al的回避程度，表明Al回避原理适用于富SiO2地区。
Molecular dynamics simulation was explored to investigate the change of structure of calcium aluminosilicate slags with varying Al2O3/SiO2 ratios at a fixed CaO content. In practice the results of the study are relevant to the significant changes in slag structure caused by the changes in chemical composition during continuous casting of steels containing high amounts of dissolved aluminum. It was found that Q4 tetrahedral species (tetrahedron with four bridging oxygens) increase while NBOs (non-bridging oxygen) decreases with increasing Al2O3/SiO2 mole ratio, suggesting that a more polymerized network was formed. The concentration of oxygen tricluster increased dramatically up to 24% with increasing Al2O3/SiO2 mole ratio, and the coordination number for Al (CNAl–O) was also observed to increase from 4.02 for sample CAS1 to 4.11 for sample CAS11, suggesting that high coordination number of Al presents in the slag melt with the substitution of [AlO4] for [SiO4]. NBOs prefer to be coordinated with Si and Al tends to be localized in more polymerized environment as network intermediate phases. The degree of Al avoidance was calculated and the Al avoidance principle is applicable in the SiO2 rich regions.