Physical properties of lightweight insulating castable refractory

September 10, 2018

Physical properties of lightweight insulating castable refractory

By selecting a lightweight mullite aggregate with a porous structure, an alumina hollow sphere and high alumina refractory fiber containing zirconium with a small thermal conductivity, the insulation performance of the furnace roll can be improved, the heat loss carried by the cooling water can be reduced; the volume density is reduced,to achieve the purpose of reducing the weight of the furnace roll and the power consumption of the rotation.

Through the addition of 0.1~1 mm coke gemstones, it compensates for the deterioration of the performance of lightweight aggregates less than 1 mm, and improves the comprehensive performance of refractory castable through the excellent thermal shock resistance and high temperature performance of coke gemstones.

Through the use of additives such as water reducing agent, organic defoaming agent and silane coupling agent, the construction fluidity of the castable is improved, the water addition amount of the castable is reduced, the construction quality and comprehensive performance of the cast lining of the furnace roll are improved.

Compared with the conventional furnace roll heavy castable (bulk density 2.2g·cm-3, thermal conductivity 0.738 W·(m·K), the bulk density is reduced by 25.8%, with lighter bulk density, the thermal conductivity is reduced by about 57%, which has better insulation effect. At the same time, the lightweight insulation castables have higher strength at low, medium and high temperature.With the increase of temperature, the mechanical properties of the castables are relatively stable, and no large fluctuations occur.

It can be seen that the reasonable design of various admixtures in the formula greatly improves the bending strength, crushing strength and mechanical vibration resistance of the lightweight castable. The compressive strength of the castable at room temperature reaches 24.5 MPa, which is much higher than that of ordinary lightweight castable. The mechanical properties not only meet the requirements of demoulding and handling, but also fully meet the requirements of the direct use of the furnace rolls after baking at 300 ° C. The rate of change of the line after each temperature treatment is small, indicating that there is better volume stability.