Permanent lining castable with low bulk density and thermal conductivity: bauxite castable for tundish obtained by adding pearlescent sand

摘要

The low thermal conductivity and light mass of castables for tundish permanent linings are crucial for minimizing the heat loss of molten steel. In consideration of the low bulk density and thermal conductivity of pearlescent sand, the thermal insulation performance of castables was attempted to be improved by adding pearlescent sand. Pearlescent sand was modified to prevent the strength of its porous structure from deteriorating. The modification mechanism of pearlescent sand and the effect of pearlescent sand on the performance of bauxite castables were studied. The results suggested that the addition of the modified pearlescent sand significantly raised the apparent porosity and decreased the bulk density of bauxite castable. At 1000 & DEG;C, the bulk density of more than 60% of the modified pearlescent sand-bauxite castable was only 2.03 g/cm(3). The mechanical properties and thermal shock resistance of the modified pearlescent sand-bauxite castable were inferior to those of conventional bauxite castable but were adequate to meet the use conditions of castables for tundish permanent linings. At high temperatures of 200-800 & DEG;C, the thermal conductivity of more than 60% of the modified pearlescent sand-bauxite castable was smaller than that of conventional bauxite castable. The addition of the modified pearlescent sand can greatly reduce the thermal conductivity and bulk density of bauxite castable.

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