Mass transfer behaviour of Mg in low carbon aluminium killed steel during LF refining

Inclusions containing Mg existed in low carbon aluminium killed steel even though Mg is not added during LF treatment. To investigate the mass transfer mechanism of Mg in low carbon aluminium killed steel, both industrial practice and kinetic calculations were carried out in the present work. The results from industrial practice showed that Mg concentration in molten steel and inclusions increased with refining time during ladle furnace treatment. The inclusion size tended to become smaller with the increase of Mg concentration in the inclusions. The erosion rate of refractory with different composition was tallied. A refractory-slag-metal-inclusion multiphase reaction model was developed to investigate mass transfer mechanism underlying the variation of Mg among the steel, the slag, inclusions and the refractory. The calculated results exhibited a good predictability of the content of Mg in the molten steel, slag and inclusions. The results showed that Mg dissolved into molten steel in two ways: the first is in the way of slag/steel reaction, the second is in the way of refractory erosion which is the main way.