完全熔融状态下SiO_2-Al_2O_3-CaO体系的黏度分析与预测

Analysis and Prediction of the Viscosity of the SiO_2-Al_2O_3-CaO Ternary System in Completely Molten State

基于网状结构模型概念，简要分析了SiO2-Al2O3-CaO体系各组分在网状结构中的作用。网状结构模型理论认为Al2O3为两性物，Al^3＋易形成四配位，部分电荷由具有较低场强的碱金属或碱土金属离子补偿。为考察SiO2-Al2O3-CaO体系随n（CaO）／[n（CaO）＋n（Al2O3）]比值变化的黏度特性，研究了n（CaO）／[n（CaO）＋n（Al2O3）]比值在0．4-0．6附近的黏温曲线变化规律。结果表明，硅熔体黏度随n（CaO）／[n（CaO）＋n（Al2O3）]比值的增大呈现先缓慢升高后降低的趋势，但当n（CaO）/[n（CaO）＋n（Al2O3）]比值为0．5时，其黏度并非为最大值。基于流体流动特性，提出了SiO2-Al2O3-CaO体系在完全熔融状态下的黏度预测模型，并同传统的Urbain模型进行比较。结果表明，本模型预测效果好于Urbain模型，预测值同实验值更为接近。

Based on the theory of random network model, the effects on the structure role in the SiO2-Al2O3-CaO ternary system for each component was analysed. The theory of random network model considers the arnphoteric role of Al2O3 in the silicate system, and its strong preference for tetrahedral coordination with its charge deficit being compensated by alkaline earth metal cations, Mn^＋ etc. For studying the varied viscosity with the ratio of n（CaO）/[n（CaO）＋n（Al2O3）] in the SiO2-Al2O3-CaO ternary system, the relationship between viscosity and component with the ratio of that typically in the range of 0.4,-0.6 was investigated. The results show that, with the ratio of n（CaO）/[n（CaO）＋n（Al2O3）] increasing from 0.4-0.6, the viscosity of the silicate melts increases slowly at first, and then decreases fiercely, but when that was at 0.5, the viscosity of silicate melts never reaches the maximum. Ground on the properties of fluid, the mathematical model for SiO2-Al2O3-CaO ternary system in completely molten state was established, which was better than the conventional Urbain model, and good agreement between experimental value and prediction one was obtained.