The Major Applications of Refractory Products

Refractory materials are used in numerous fields of the national economy, such as steel, non-ferrous metals, glass, cement, ceramics, petrochemicals, machinery, boiler manufacturing, light industry, electric power, military industry, etc. It is an indispensable basic material to ensure the production, operation, and technological development of the mentioned industries. Let's take a look at major applications of refractory products.

Furnace: units used in the metal foundry industry are lined with various refractory components (including silicon dioxide, aluminosilicate, high alumina, zirconium, magnesium oxide, spinel, chromium, and magnesium carbon) and forms (overall, prefabricated shapes and bricks). Most smelting furnaces and holding furnaces in the metal foundry industry are equipped with ceramic refractory materials. The selection of these refractory materials is designed to minimize the reaction with the specific metal being processed. The main refractory lining devices include reverberation furnace, crucible (pot) furnace, trough induction furnace, coreless induction furnace, electric arc furnace, and ladle furnace. These furnaces are lined with various refractory materials, including silicon dioxide, alumina silicate, high alumina, zircon, magnesia, spinel, chromium, and magnesia carbon.

Missile: Improved pneumatic valve and improved thrust directional valve missile. In one embodiment, the refractory lining for pneumatic valves allows for better valve operation and better valve performance. A thin-walled cylindrical sleeve made of rhenium or other suitable refractory metal is contained in the cylinder. Therefore, the valve piston can move in the refractory sleeve, with higher reliability and better performance. Refractory sleeve cylinder liner can quickly withstand high temperatures and keep running. In such a harsh environment, including the corrosive/erosive environment generated by the passage of hot propellant gas, the refractory cylinder liner has a more reliable service life and is lighter than a traditional valve made entirely of refractory metal.

Gas turbines: Driven by the increased combustion temperature of gas turbines and the need for better emission control, the use of complex materials and processes has promoted the major development of combustion hardware. The main basis for the material changes that have been made is to improve high-temperature creep resistance without sacrificing oxidation/corrosion resistance. Traditionally, the components of the combustion chamber were made of rolled nickel-based superalloys. Hastelloy X is a material with higher creep strength and was used between the 1960s and 1980s. Nimonic 263 was introduced later and has higher creep strength. As the combustion temperature of the new HA-188 gas turbine model further rises, cobalt-based superalloys have recently been used in certain parts of the combustion system to improve the creep rupture resistance.

Bio-fuel boiler: Refractory materials are used in the internal structure of biofuel boilers (lining). These materials are non-metallic inorganic materials, which do not melt or decompose at high temperatures (600-2000°C). The main components of the lining are made of shaped refractories (bricks, blocks, etc.) and unshaped (concrete, mortar, lining, etc.).

Rocket Nozzle: Refractories are mainly used in ultra-high temperature areas. The area most affected by high temperatures in rockets is the nozzle throat area. Rocket nozzles are widely used in mechanical components such as tactical missiles and weather surveillance satellites. This rocket nozzle works at high temperatures because a large amount of high-temperature exhaust gas produced by combustion passes through the throat area, which is the area with the smallest cross-sectional area. Therefore, the material of the rocket nozzle must have good mechanical properties, such as high melting point, good thermal shock resistance, and low thermal expansion coefficient to maintain propulsion performance. Refractory materials including niobium, tantalum, molybdenum, and tungsten have strong heat resistance and wear resistance. These materials have unique mechanical properties such as high melting points, boiling points, and densities. Among all refractory materials, rhenium has unique mechanical properties.

Combustion chamber partition wall: Silica bricks are mainly used to build partition walls of coke oven carbonization combustion chambers, open-hearth regenerators, high-temperature load-bearing parts of hot blast stoves, and other high-temperature furnaces. The SiO2 content of silica bricks is more than 93%, the main component is phosphorous quartz, cristobalite, residual quartz, and glass.

The overall lining of furnaces: Ramming materials are mainly used for the general lining of various industrial furnaces, such as open hearth bottom, electric furnace bottom, induction furnace lining, ladle lining, threading trough, etc. The ramming material is a bulk material formed by a strong ramming method, which consists of a certain size of refractory material, binder, and an additive.

Metallurgy Industry: High alumina bricks are mainly used in the metallurgical industry to construct plugs and nozzles for blast furnaces, hot blast stoves, electric furnace roofs, steel drums and pouring systems. More than 48%, mainly composed of corundum, mullite and glass.