Dissolution behaviour of lime in converter slag: evolution of morphology and ions migration

Abstract

The dissolution behaviour of lime in converter slag at 1300–1500 °C was studied, and the evolution of morphology and component ions migration under different dissolution time were examined. The results showed that with the increase of dissolution time, the lime surface changed from irregular to regular, and micropores and cracks were formed. The lime melting is a diffusion phenomenon, the slag promoted lime dissolution through these cracks and micropores, the mass transfer coefficient of Fe2+ in the boundary layer is the smallest, which is 5.4 × 10−7 cm/s, and the linear equation fitting the reaction rate constant versus temperature is ln vr = –24.43/T - 14.62. Moreover, the lime dissolution was a process of melting from outside to inside, layer by layer, the CaO-SiO2 complex phases were formed on the surface of lime and CaO-FeO complex phases were formed inside.