Dissolution Behavior of Slag Modifiers in Molten BOF Slag

Ir. Gaurav Tripathi, Dr. Annelies Malfliet, Prof. Bart Blanpain, Dr. Muxing Guo

In recent years, many possibilities have been explored for the valorisation of Basic Oxygen Furnace (BOF) slag. BOF slag amounts to nearly half of the substantial quantities of steel slag being produced in Europe. By hot stage engineering of BOF slag, for instance by adding slag modifiers such as Al2O3 or SiO2, the final slag composition and mineralogy can be influenced to allow its subsequent utilization as a high added value material. The dissolution behavior of these modifiers into the slag is of significant importance to optimize the hot stage slag engineering. Fast dissolution is desired to allow sufficient time for the modifiers to react with other components in the slag, for instance to stabilize free CaO and MgO. In this study, the dissolution behavior of Al2O3 particles in molten BOF slag has been studied between 1500 and 1600 °C. The Al2O3 particles dissolve incongruently in the slag. The various phases formed during the dissolution process and their behavior in the dissolution zone have been studied for a better understanding of the process.