CORROSION BEHAVIOR OF MgO-C REFRACTORY ACCOMPANIED BY BUBBLE FORMATION IN MOLTEN SLAG

摘要

The corrosion test of magnesia-carbon refractory, MgO-C refractory, has been carried out by rotating the cylindrical samples in molten slag at 1673K. The corrosion behavior was affected by the slag composition. The decrease of corrosion rate was observed with the decrease of the contents of MgO in the slag. The rotation speed did not affect the corrosion rate at the rotation speed from 0 to 300 rpm. The experimental result suggested that the movement of CO bubble through the boundary layer affected strongly the dissolution rate of MgO grains. To ascertain the effect of the movement of CO bubble on the dissolution rate of MgO grain, a simulated experiment was performed at room temperature. The bubble was formed in the pore and was detached from the rotating cylinder by buoyancy in the solution. The rate of the increase of the pore size was proportional to the number of bubbles being detached from the pore per unit time, and was not affected by the rotating speed. It was speculated that the MgO grain of MgO-C refractory dissolved rapidly in the slag because the slag convection flow into the pore occurred accompanying by the detachment of CO bubbles from the surface of the refractory. The reduction of the rate of CO bubble formation is effective to improve the corrosion resistance of MgO-C refractory in molten slags.