INFLUENCE OF MAGNESIUM SULFATE SOLUTION IMPREGNATION ON HYDRATION RESISTANCE OF MAGNESIA-CHROME BRICKS

摘要

The fused-rebonded magnesia-chrome bricks with 26% Cr_2O_3 were vacuum impregnated by magnesium sulfate (MgSO_4) solution. The physical properties of specimens before and after impregnation such as bulk density, apparent porosity, CCS, CMOR and HMOR ( 1450°C, 0.5h ) were analyzed. The pore size distribution of the specimens before and after impregnation was measured by the aid of mercury porosimeter. Hydration resistance and slag resistance of the specimens with and without the impregnation were compared by autoclave test and crucible slag test at 1600°C for 3h respectively. The microstructure of the specimens was characterized by means of SEM and EDS.The results showed that: The hydration resistance of the impregnated specimen was remarkably improved. Apparent porosity and the pore size of the specimens were decreased by MgSO_4 solution impregnation. The percentage of the pores over l0μm decreased to 67.67% from 84.13% before the impregnation. CCS and CMOR of the specimens increased significantly after the impregnation. The impregnated specimen showed better slag resistance than the unimpregnated one. The impregnation had little effect on HMOR.