A BASIC BRICK CONTAINING FUSED MgO-TiO_2-CaO AGGREGATES FOR LIME FURNACE

摘要

Due to chemical corrosion by the interface of spinel basic brick and lime in the hot zone of the vertical lime furnace, different particle size and concentration of fused MgO-TiO_2-CaO (MTC) aggregates were studied in the development of a new MgO corrosion resistance brick. The oxide composition of MTC used was 78% MgO, 12.5% TiO_2 and 6.5% of CaO, which promoted the most adequate thermal and mechanical properties. The best physical properties obtained were for bricks containing 30% of MTC when compared to a standard spinel brick, that is: lower apparent porosity and higher abrasion resistance and better mechanical properties. The thermal shock resistance was similar to spinel brick composition. Comparative lime corrosion test with conventional MgO, used on the hot zone of vertical lime furnace, and MTC bricks was conducted using a rotary furnace at 1500°C for 720 minutes. The corrosion products were characterized using the following techniques: Chemical Analysis; X-Ray Diffractometry (XRD); Scanning Electronic Microscopy (SEM-EDS); Mercury Porosimetry and Helium Picnometry.