Because they can withstand pressure, chemicals, and heat while maintaining strength and form, refractories are a crucial component of inner furnace linings in big businesses. Steel has a melting point of about 2,802°F, whereas it can withstand temperatures from 500 to 3,326°F. Refractory materials have a melting point that ranges from 3,300°F to 6,000°F in their purest form.
Despite the brief hiatus brought on by the COVID-19 epidemic, the construction sector is expanding quickly, particularly in developing countries like India and China.
With the expansion of infrastructure, demand for steel and iron is skyrocketing across various industries, including transportation (roads, rails, and residential buildings). As a result, the need for refractories would be fueled by the growing building activity.
Usage of Refractories
• The linings for kilns, furnaces, incinerators, and reactors are made of refractory materials.
• Additionally, they are used to surface flame deflector devices for rocket launch structures and to create crucibles and molds for casting glass and metals.
• The usage of refractories in the iron and steel industry today accounts for around 70% of total production.
• Production of metals, glass, paper, and cement
Refractory Advantages
Refractoriness- Refractoriness is the capacity to tolerate extremely high temperatures without melting or deforming under specific service circumstances.
• Under-Load Refractoriness (or Strength)
When employed in metallurgical processes, refractories should support a range of loads. For this reason, it is crucial that refractory materials have great mechanical strength, even at working temperature, in order to support the largest load without breaking.
• Measurement Stability
Dimensional stability refers to a material’s resistance to any volume change when subjected to high temperatures over an extended period of time.
• Thermal Deflation and Growth
Solid solids expand and compress when heated and cooled, respectively. A refractory material must have the least amount of thermal expansion feasible for developing practical furnaces.
• Texture
Due to their high porosity and low weight, textured bricks are more resistant to rapid fluctuations in temperature. However, they have weak crushing power. These bricks are more vulnerable to corrosion and abrasion.
As opposed to coarse and light-textured bricks, which have high porosity, fine or dense-textured bricks have low porosity and are hence heavier. These are less resilient to abrupt temperature fluctuations. These bricks are less prone to corrosion and action, nevertheless.
• Thermal Spalling
Internal stresses and strains emerge as a result of the unequal contraction and expansion of refractory materials brought on by rapid temperature fluctuations. The term “thermal spalling” refers to the cracking, breaking, or fracturing of refractory brick when exposed to high temperatures.
• Inertness to Chemicals
A refractory material used as a furnace wall liner should be chosen such that it is inert in operation and does not produce flammable byproducts when charged with fuel ashes, slags, furnace gases, and other chemicals.
• Heat Absorption
The heavy and dense fore clay bricks are suitable for regenerators, and checker-works, including in stoves for coke ovens, blast furnaces, etc., since they have a larger heat capacity.