The formation of an inner slag layer during the dissolution of MgO particles in ladle slag

摘要

The presence of nonmetallic inclusions is a significant problem during clean steel production. One of the major tasks in steelmaking is to control the amount, size, and distribution of inclusions, as well as to removing them from molten steel as much as possible. In this present work, four types of slag with different basicity, MgO and Al2O3 content were used to simulate the ladle refining slag. The effects of slag composition and temperature on the dissolution rate of MgO particles were investigated using the direct dissolution method. The experimental results show that the dissolution rate of MgO particles strongly depends on the slag compositions and temperature. During dissolution process, once spinel product forms around the MgO core, the dissolution rate decreases remarkably. The formation and function of the inner slag layer between the MgO core and the spinel product were investigated in detail. The inner slag was possible to act as a transfer passage for Mg element from the MgO core to the spinel product. The rate-limiting step of MgO dissolution was determined by the diffusion of spinel product toward the bulk slag.