Corrosion Behavior of Various Refractory in Molten Slag

摘要

The corrosion tests of sintered MgO, electro-fused Al_2O_3, MgO-C, MgO-C with a dense layer, Al_2O_3-NiO and Al_2O_3-Cr_2O_3 brick were carried out in CaO-SiO_2-Fe_xO-CaF_2 melt under forced convection conditions at 1673K. The corrosion rate was obtained by the decreasing of the radius of the rotating cylinder per unit time. EPMA analysis was carried out for the cross section of the cylinder after the corrosion test to observe the corroded surface of the refractory and the change of the constituent concentration of the slag penetrated into the pore. The rate-determining step, which was mass transfer through the boundary layer, in the corrosion process was classified into three types. They were normal diffusion of the solute, accelerated mass transfer by moving bubbles and decreased mass transfer by prevention of the slimy layer or the suspension around the refractory. The dissolution of the bonding part of the grains depended on the activity of the refractory constituents in the penetrated slag through the pores. The instructions of the development of new refractory with high corrosion resistance were given from the results of the study.