Al2O3-SiO2-CaO-FeO四元体系煤灰结构及流动性关系的实验和理论研究

将分子动力学、热力学计算与实验结合研究了Al₂O₃-SiO₂-CaO-FeO四元体系灰渣黏度变化机理。在Al₂O₃-SiO₂-CaO-FeO四元体系中，钙铁质量比（简称钙铁比，下同）增加，黏度下降，黏温曲线类型由结晶渣转变为玻璃渣，钙铁比为2时为黏温特性转变的拐点。钙铁比小于2时，体系中的矿物质主要是结晶矿物质，体系中降温过程中生成晶体矿物较多，当钙铁比大于2时，体系以无定形矿物质为主；从微观角度分析，钙铁比增加导致体系中Al由六配位（AlO₆]^9-）转变为四配位（AlO₄]^5-），钙铁两种原子对体系中六配位铝的影响存在竞争作用。体系中的桥氧含量降低，体系的聚合程度降低，稳定性降低。通过四元体系的氧键为桥梁，建立了碱性组分含量与黏度的函数关系。

Experimental and theoretical investigation on relationship between structures of coal ash and its fusibility for Al2O3-SiO2-CaO-FeO system

The molecular dynamics simulation, thermal dynamic calculation and experimental investigation were combined to illustrate ash slag viscosity variation mechanism for Al₂O₃-SiO₂-CaO-FeO system. The viscosity declines and the viscosity curve is transformed from crystalline slag to glassy slag with increasing mass ratio (C/F) of calcium to ferrous oxide in Al₂O₃-SiO₂-CaO-FeO system. There is an inflexion point when the C/F is equal to 2. When the C/F is below 2, there are mainly crystalline minerals in the system. While the C/F is above 2, there are mainly amorphous minerals in the system. With the increase of C/F, six-coordinated Al (AlO₆]^9-) is transformed to four coordinated Al(AlO₄]^5-) microscopically. Besides, the content of bridging oxygen decreases while that of non-bridging oxygen increases. Quantified function between base composition and viscosity are constructed based on the stability coefficients defined by oxygen bond species.