CaO-SiO2-Al2O3-MgO-Na2O (CSAMN), as a basic system, has been extensively studied and widely applied in the field of mold flux. The thermal conductivity parameter of melt film as a critical indicator affects the heat transfer during the continuous casting process. However, many details of the CSAMN thermal conductivity still remain unclear. Herein, the thermal conductivity of the molten CSAMN system under different compositions was calculated at 1773 K based on equilibrium molecular dynamics simulation. The structure of the CSAMN system was further investigated to explore the relationship between composition and thermal conductivity. The results show that the thermal conductivity of CSAMN melt has a significant positive correlation with the CaO/SiO2 (C/S) mole ratio. The Si-O/Al-O network depolymerizes with an increase in the C/S mole ratio and polymerizes with the increasing Al2O3/SiO2 (A/S) mole ratio. The bridging role of Ca2+ is enhanced with the increase in the C/S mole ratio and slightly decreases with the increasing A/S mole ratio. The connection of the Al-O and Si-O network and the bridging role of Ca2+ promote phonon transmission, which in turn increases the thermal conductivity of the CSAMN melt.

中文翻译：

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CaO-SiO2-Al2O3-MgO-Na2O 熔体热导率的计算洞察

CaO-SiO2-Al2O3-MgO-Na2O（CSAMN）作为一种基本体系，在保护渣领域得到了广泛的研究和广泛应用。熔膜热导率参数作为关键指标影响连铸过程中的传热。然而，CSAMN 热导率的许多细节仍不清楚。在此，基于平衡分子动力学模拟计算了不同成分下熔融 CSAMN 系统在 1773 K 时的热导率。进一步研究了 CSAMN 系统的结构，以探索组成与热导率之间的关系。结果表明，CSAMN熔体的热导率与CaO/SiO2(C/S)摩尔比呈显着正相关。Si-O/Al-O 网络随着 C/S 摩尔比的增加而解聚，并随着 Al2O3/SiO2 (A/S) 摩尔比的增加而聚合。Ca2+ 的架桥作用随着 C/S 摩尔比的增加而增强，并随着 A/S 摩尔比的增加而略微降低。Al-O 和 Si-O 网络的连接以及 Ca2+ 的架桥作用促进了声子传输，进而增加了 CSAMN 熔体的热导率。