Fe_(x)O-SiO_(2)-CaO-MgO-“NiO”系镍渣势函数及分子动力学模拟

Potential Function and Molecular Dynamics Simulation for Fe_(x)O-SiO_(2)-CaO-MgO-“NiO”Nickel Slag

从非经验参数角度构建基于两原子模型的Fe_(x)O-SiO_(2)-CaO-MgO-"NiO"渣的势函数,利用分子动力学模拟揭示调控镍渣组分与结构及物理化学性能之间的关系。结果表明:BMH(Born-Mayer-Huggins)势函数能够较好表征Fe_(x)O-SiO_(2)-CaO-MgO-"NiO"系镍渣的势能。当镍渣中CaO含量为15 wt.%时,Si4+-Si4+间配位数最小,此时熔渣的聚合度最低,有利于扩散。当Fe元素由Fe^(2+)转换为Fe^(3+)后,和O^(2-)结合能力更强,会导致熔渣更难以扩散,因而镍渣的黏度迅速升高,造成冶炼条件恶化,因此在镍闪速熔炼时要严格控制Fe^(2+)/Fe^(3+)的比例。模拟计算的黏度与实测值吻合较好,表明构建的势函数能够较好地反映镍渣的物化性能。

Potential function ofFe_(x)O-SiO_(2)-CaO-MgO-"NiO"nickel slag in a two-atom model is constructed with nonempirical parameters.Microstructure and physicochemical properties of nickel slag are explored with molecular dynamics simulation.It shows that the potential energy ofFe_(x)O-SiO_(2)-CaO-MgO-"NiO"nickel slag can be characterized well with BMH(Born-Mayer-Huggins)potential function.It is beneficial to diffusion as CaO content of nickel slag is 15 wt.%,at which the coordination number of Si4+-Si4+and the polymerization degree of slag are the lowest.The binding capacity of Fe with O^(2-)become stronger as Fe element is converted from Fe^(2+)to Fe^(3+),which makes the slag difficult to diffuse.It makes the viscosity of nickel slag increases rapidly and the smelting conditions become deteriorate.Therefore,the ratio of Fe^(2+)/Fe^(3+)should be controlled strictly during nickel flash smelting.The simulated viscosity is consistent with measured value.It shows that the potential function reflects physical and chemical properties of nickel slag well.