Characteristics of lightweight refractory bricks

In contemporary industries where mineral resources are becoming increasingly scarce, eco-friendly and environmentally friendly refractory products have become the first choice for thermal enterprises, and the use of lightweight refractory bricks is increasing day by day. Lightweight refractory bricks are characterized by good thermal insulation properties. It can reduce the weight of the kiln body during use, thereby reducing energy consumption and improving the economic benefits of the enterprise.

Lightweight insulating bricks are a type of insulating refractory material, which refer to refractory bricks with high porosity, low volume density and low thermal conductivity. Lightweight refractory bricks are characterized by their porous structure and high thermal insulation.

There are many classification methods for lightweight refractory bricks:

1. Classified by volume density, those with a volume density of 0.4-1.3g/cm³ are ultra-lightweight refractory bricks.

2. Classification according to usage temperature. The use temperature is 600-900℃ for low-temperature insulation materials; the temperature between 900-1200℃ is medium-temperature insulation material; the temperature exceeding 1200℃ is high-temperature insulation material.

3. Classify according to product shape. One is shaped lightweight refractory bricks, including clay insulating refractory bricks, high alumina insulating refractory bricks, siliceous refractory bricks and some pure oxide lightweight refractory bricks; the other is unshaped lightweight refractory bricks , such as lightweight refractory concrete, etc.

The heat storage loss of industrial kiln masonry and the heat dissipation loss of the furnace surface generally account for about 24% to 45% of fuel consumption. Using lightweight refractory bricks with low thermal conductivity and small heat capacity as the furnace body structural material can save fuel consumption; at the same time, because the kiln can heat up and cool down quickly, it can improve equipment production efficiency; it can also reduce the weight of the furnace body and simplify the kiln. The furnace structure improves the quality of refractory bricks, reduces the ambient temperature and improves working conditions.

The disadvantages of lightweight refractory bricks are large porosity, loose structure, and poor slag resistance. Molten slag quickly invades the pores of the refractory brick body, causing it to fragment. It cannot be used in direct contact with molten slag and liquid metal; It has low mechanical strength, poor wear resistance and poor thermal stability. It cannot be used in load-bearing structures, nor should it be used in parts that are in contact with the furnace charge and suffer serious wear.

Due to the above-mentioned characteristics of lightweight refractory bricks, lightweight refractory bricks are generally not used in industrial kilns in areas of the furnace that are in contact with the charge, where there are slag and high-velocity hot air to neutralize large mechanical vibrations. Lightweight refractory bricks are often used as the thermal insulation layer, lining or insulation of kilns.