Study on the Structure and Properties of High-Calcium Coal Ash in the High-Temperature Zone of a Blast Furnace: A Molecular Dynamics Simulation Investigation

Molecular dynamics simulations were carried out to study the behavior of high-calcium coal ash in the high-temperature zone of a blast furnace. The radius distribution function, coordination number, structural unit, transform performance, and fluidity were analyzed. The results showed that CaO did not cause significant variation of the Si-O bond length in the aluminosilicate, except when the CaO content reaches 40%. The simulation results indicated that, as the CaO content increases, the transport properties of the coal ash will become better and the viscosity will accordingly be lower. The reason for this phenomenon is that CaO depolymerized the microscopic network structure of the aluminosilicate, which caused more bridge oxygen to convert to non-bridge oxygen, thereby reducing the degree of polymerization of the system. Meanwhile, through the analysis of potential energy, it was also proved that CaO has the function of improving the system energy and reducing stability. Our studies have fully related the viscosity change and microstructure of high-calcium coal ash in the high-temperature zone of a blast furnace.