Factors affecting heat insulation of lightweight refractories

2. Analysis of factors affecting heat insulation of lightweight refractories
(3) Bulk density
The thermal conductivity of lightweight refractories has a linear relationship with bulk density, that is, the thermal conductivity increases with the increase of bulk density. The volume density directly reflects the internal porosity of the lightweight refractory. The low volume density indicates that the product has more pores, the contact points between the solid particles are reduced, the solid phase conductivity of heat is reduced, and the thermal conductivity will be low.
(4) Temperature
The thermal conductivity of lightweight refractories has a linear relationship with temperature, that is, the thermal conductivity increases with the increase of temperature. However, compared with dense refractories, the thermal conductivity of lightweight refractories increases much smaller with temperature. This is because the dense refractory material mainly transfers heat in the solid phase. When the temperature increases, the thermal movement of the molecules in the product is intensified, which improves the thermal conductivity. In light refractory materials, most of the structure is gas phase structure (65-78%), and the thermal conductivity of the gas phase changes less than the solid phase when the temperature rises.