The influence of secondary aluminum dross on lime desulfurization for hot metal

The desulfurization effect of CaO-secondary aluminum dross (SAD) composite desulfurizer in hot metal was studied in present work. The thermodynamic reaction mechanism of desulfurization with CaO as desulfurizer under the action of SAD was discussed. The experimental results indicated that the desulfurization ability of CaO significantly improved with the addition of SAD. Metallic aluminum can effectively reduce the oxygen potential in molten melt, which is conductive to the thermodynamics conditions of desulfurization reactions. When CaO-SAD composite desulfurizer is used, C3A calcium aluminate with low melting point can be generated, which improves the fluidity of desulfurizer at experimental temperatures. Meanwhile, it prevents the formation of high melting point 2CaO<middle dot>SiO2 on the surface of lime particles and promotes a sustainable desulfurization reaction. When the ratio of CaO/SAD is 0.9 and 1.0, the utilization rate of CaO in desulfurizer is about 10%, which is higher than that of calcium-aluminate based desulfurizer. The application of SAD as a desulfurizer for hot metal in the steel industry can provide a new approach for the comprehensive utilization of SAD.