Thermodynamics of mixing and ordering in solid solutions with coupled substitutions: A computer simulation approach

耦合取代固溶体中混合和排序的热力学：计算机模拟方法

• 批准号: 5447106
• 负责人: Professor Dr. Björn Winkler
• 金额: --
• 依托单位: Fachrichtung Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5447106?language=en
• 关键词: Thermodynamics; mixing; ordering; solid; solutions

The chemical variability of many rock-forming minerals - solid solutions, is determined bythe coupled-substitution mechanism. This mechanism permits a cation to enter the lattice of ahost mineral even when its charge does not match the average charge of the particular site.The termodynamic behaviour of such solid solutions is complicated due to the development ofcationic order both at inermediate and at the end-member compositions. Static lattice energycalculations (SLEC) and Monte Carlo simulations are the only tools which permit relatisticmodeling of these phase. The success of this approach is determined by the quality of theempirical interatomic potentials used to constrain the SLEC. We propose to make the use ofan already developed self-consistent set of interatomic potentials for the system Si4+, Al3+,Mg2+, Ca2+, Na+, K+, Fe2+, Fe3+, Mn2+, Ti4+, ZR4+, Y3+, P5+, O2-, which shows goodperformance in predicting magnitudes of the mixing and ordering enthalpy in a variety ofminerals and industrially important compounds. The main outcomes of the project will be thedevelopment of realistic activity-composition models for solid solutions with coupledsubstitutions such as CaMg, = (Na,K)(Al, Fe3+) in clinopyroxene, Mg,Si=Al,Al inclinopyroxene and perovskite, (Na,K)Si=CaAl ind feldspar and Si,Zr4+=P5+, Y3+ in zircon.

许多岩层矿物质的化学变异性 - 固体溶液，由耦合验证机制确定。这种机制允许阳离子进入Ahost矿物的晶格，即使其电荷与特定位点的平均电荷不符合。由于在无数和末端成员组成上的阳离子的发展，这种固体溶液的术语动力学行为变得复杂。静态晶格能量量表（SLEC）和蒙特卡洛模拟是唯一允许对这些阶段进行相对模拟的工具。这种方法的成功取决于用于限制SLEC的经验质量。我们提议使AN的使用已经开发了系统Si4+，Al3+，Mg2+，Ca2+，Na+，K+，Fe2+，Fe3+，Fe3+，MN2+，Ti4+，Zr4+，Zr4+，y3+，y3+，p5+，p5+，o2-，这显示出良好的峰值和量中的序列，以及量的混合和序列的杂物和序列，并且有量的混合和量的杂物，工业重要的化合物。 The main outcomes of the project will be thedevelopment of realistic activity-composition models for solid solutions with coupledsubstitutions such as CaMg, = (Na,K)(Al, Fe3+) in clinopyroxene, Mg,Si=Al,Al inclinopyroxene and perovskite, (Na,K)Si=CaAl ind feldspar and Si,Zr4+=P5+, Y3+ in锆石。