Estimation of thermodynamic properties of molten fluxes by molecular dynamics

通过分子动力学估计熔融熔剂的热力学性质

• 批准号: 11650757
• 负责人: TSUKIHASHI Fumitaka
• 金额: $ 2.3万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650757/
• 关键词: molecular dynamics; thermodynamics; phase diagram; potential function; refining; flux; fluoride; oxide; 分子動力学法; ポテンシャル

Calculation of the thermodynamic properties of molten oxides is useful for the development of reining of metals in case that the measurement of properties is experimentally difficult. The molecular dynamics and the molecular simulation are very effective method for the estimation of the properties of gas and liquid phases. The purpose of this study is to establish the estimation method of the thermodynamic properties of ionic solutions by using the molecular dynamics.In this study, the thermodynamic properties of melts of calcium, oxide and halide mixture such as Ca-CaO-CaF_2 melt were calculated, since these fluxes are used for the purification of metals and the measurement of the thermodynamic properties of these melts is difficult.The potential function of components such as CaO, CaF_2, CaCl_2, BaO, BaF_2, etc. was investigated for the calculation of molecular dynamics. A lot of potential functions are reported for ionic material. However, the potential function that is suitable for the estimation of all properties is not available. In this study, the Born-Mayer type potential and the soft core potential was applied and the parameters of potentials were determined by comparing the observed melting point of ionic solutions and the calculated one. The Gibbs free energy of the CaO-CaF_2, CaF_2-BaF_2, BaO-BaF_2 systems were calculated by using the potential parameters of compounds and the stability of the systems were discussed. The phase diagrams were obtained from the calculated thermodynamic propertied such as the Gibbs free energy. Furthermore, the activities of components were calculated.It is shown in this study that the thermodynamic properties of ionic melts can be estimated by the molecular dynamics.

熔融氧化物的热力学特性的计算对于在实验上的测量很难进行测量时，对于金属的重新制定很有用。分子动力学和分子模拟是估计气体和液相性质的非常有效的方法。这项研究的目的是通过使用分子动力学来建立离子溶液的热力学特性的估计方法。在这项研究中，计算了钙，氧化物和卤化物混合物（例如CA-CAO-CAF_2）的热力学特性，例如CA-CAO-CAF_2熔体，由于这些通量用于纯化金属，并且这些熔体的热力学特性的测量很困难。动力学。报道了离子材料的许多潜在功能。但是，尚无适合所有属性估计的潜在函数。在这项研究中，应用了伯恩型电势和软核电位，并通过比较观察到的离子溶液的熔点和计算出的参数来确定电位的参数。通过使用化合物的潜在参数计算CAO-CAF_2，CAF_2-BAF_2，BAO-BAF_2系统的Gibbs自由能，讨论了系统的稳定性。相图是从计算出的热力学性质（例如Gibbs自由能）获得的。此外，计算了组件的活性。这在这项研究中表明，离子熔体的热力学特性可以通过分子动力学估算。