TiO2-FeO-Ti2O3体系熔体局域结构和输运性质的机器学习分子动力学模拟

Machine Learning Molecular Dynamics Simulations of Local Structure and Transport Properties of TiO2-FeO-Ti2O3 Melt

  • 摘要: 钛铁矿还原熔炼过程存在反应速率不高、渣铁分离不好、钛渣质量不优的问题。钛渣熔体输运性质的调控是实现高品质钛渣高效制备的关键。本论文采用神经网络训练得到机器学习势函数,并根据原子力和体系能量验证其准确性。本论文采用获取的机器学习势函数,开展了TiO2-FeO-Ti2O3体系的局域结构和输运性质的分子动力学模拟。结果表明:TiO68-八面体和TiO69-八面体参与网络骨架的构建,TiO68-八面体的稳定性大于TiO69-八面体。不同FeO含量下,体系中TiO68-和TiO69-占比都占主导地位。当FeO含量从5%增加到19%时,体系中团簇氧和桥氧向非桥氧和自由氧转变,体系的DSC值从1.37降低到0.62,Q4、Q5和Q6转变为Q0、Q1、Q2和Q3,DOP值从4.34降低到1.84。当FeO含量从5%增加到19%时,体系的复杂度和聚合度降低,网络骨架的整体强度降低,体系的黏度值从0.043 Pa·s降低到0.037 Pa·s。本论文的研究结果将为高品质钛渣的低碳、高效制备奠定理论和技术基础。

     

    Abstract: There are some problems in the reduction smelting process of ilmenite, such as low reaction rate, poor separation of slag and iron, and inferior quality of titanium slag. The control of the transport properties of titanium slag melt is the key to achieve the efficient preparation of high-quality titanium slag. This work uses neural network to obtain machine learning potential function, and verifies its accuracy according to atomic force and system energy. In this work, the molecular dynamics simulation of the local structure and transport properties of TiO2-FeO-Ti2O3 system is studied by using the obtained machine learning potential function. The results show that TiO68- octahedron and TiO69- octahedron are involved in the construction of network skeleton, and the stability of TiO68- octahedron is higher than that of TiO69- octahedron. Under different FeO contents, the proportions of TiO68- and TiO69- octahedron in the system are dominant. When the content of FeO increases from 5% to 19%, the tricluster oxygen and bridge oxygen in the system are transformed into non-bridge oxygen and free oxygen, the DSC value of the system decreases from 1.37 to 0.62, Q4, Q5 and Q6 are transformed into Q0, Q1, Q2 and Q3, the DOP value decreases from 4.34 to 1.84. When the content of FeO increases from 5% to 19%, the complexity and polymerization degree of the system decrease, the overall strength of the network skeleton decreases, and the viscosity value of the system decreases from 0.043 Pa·s to 0.037 Pa·s. The results will lay a theoretical and technical foundation for the low-carbon and efficient preparation of high-quality titanium slag.

     

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