This book presents the physicochemical properties and structure of high-alumina slag in the ironmaking process. The book consists of seven chapters demonstrating the effect of Al2O3 on the properties and structure of slag. Based on experimental research and practical requirements, a revolutionary technical route for blast furnace smelting of high-alumina iron ore is proposed. The book presents the scientific basis and offers theoretical guidance for the large-scale utilization of high-alumina iron ore in ironmaking process. Therefore, it is of interest for not only academic researchers but also practitioners in this field.