Refractory bricks are made of heat-resistant ceramic materials, similar in shape to ordinary building bricks, so they are often used in building kilns and various thermal equipment.The main component of refractory bricks is alumina, which can be up to 50-80%. Relatively, the silicon content is less.
High temperature refractory brick
Silica-containing refractory bricks can be used in steelmaking furnaces up to 1648°C (3000°F), which can melt many ceramics, and even refractory bricks will partially melt. The high-temperature surface insulation tiles (HRSI) used in the space shuttle’s insulation system are also made of the same material, which is used in the space shuttle’s insulation.
Alkaline refractory bricks are used for the smelting of non-ferrous metals, because these refractory bricks will continuously dissolve the acidic silicon-containing slag. The most commonly used refractory bricks are chrome-magnesite or magnesite-chrome refractory bricks (depending on the proportion of magnesite and chromite)
Low temperature refractory brick
Many materials can be used as lower temperature refractory bricks. Magnesium oxide is often used as the inner lining of the furnace, and silicon-containing refractory bricks are the most common linings in furnaces and waste incinerators. The inner lining of the inner layer is generally used as a sacrificial part, and high-aluminum-containing refractory bricks can be used to prolong the time that the inner layer can withstand. Refractory bricks often see cracks on the inner layer after starting to use, which means that more expansion joints are needed when they are used for the first time. However, the inner layer is now used as expansion joints. As long as the integrity of the structure is not affected, there is no problem. Silicon carbide with high corrosion resistance is commonly used in waste incinerators and cremation furnaces. Red refractory bricks are used for chimneys and wood-burning ovens.