In-situ X-ray Observation and Microstructural Analysis on Slag Penetration into Magnesia Refractories

摘要

The behavior of slag penetration into MgO refractory was investigated by combining in-situ X-ray observation with microstructural analysis of the samples after penetration experiments. The following results are obtained: The slag penetrates rapidly into the refractory, reacting with MgO particles in the refractory. The slag penetrates unevenly into the refractory with uneven pore size in a path like a tree, firstly along the main path (large pore), and then extending to the branch path (small pore), while evenly into the refractory with even pore size. The rate of slag penetration increases with increasing pore radius of the refractory, T. Fe concentration in the slag and experimental temperature, and with decreasing the slag basicity (C/S ratio). In the case of the 10mass percent Al_2O_3-bearing slag, the rate of slag penetration is less than that of the Al_2O_3-free slag in the initial stage. The penetration of the 10mass percent Al_2O_3-bearing slag into the sample with the apparent porosity of 31 percent stopped after reaching 23mm in height under the present experimental conditions, which was much smaller than that of the Al_2O_3-free slag. In the initial stage of penetration, the penetration height is proportional to the square root of penetration time, and the penetration behaviors of the slag can be qualitatively explained based on a capillary model. The penetration of the Al_2O_3-bearing slag is remarkably suppressed by the formation of MgO-FeO- Al_2O_3 spinel caused by the reaction of Al_2O_3 and FeO in the penetrated slag with MgO particles and MgO dissolved from the refractory.