Types and uses of refractory materials

Types and uses of refractory materials

Refractory materials refer to materials that can maintain their stable structure and performance under high temperature environment. They are widely used in high-temperature industrial furnaces, kilns, furnace linings and other equipment in metallurgy, ceramics, glass, cement and other industries. The following are the types of refractory materials and their main uses:

Classification by composition

1. Acidic refractory materials

Quartz bricks: Made of quartz sand, with high refractoriness, good acid resistance, but poor alkali resistance.

Alumina silicate bricks: Containing bauxite or bauxite, widely used, with good thermal stability and chemical stability.

Clay bricks: With refractory clay as the main raw material, containing 30%~46% alumina, good thermal vibration resistance, and corrosion resistance to acidic slag.

Main ingredients: mainly silicon dioxide (SiO₂).

Features: Has good acid resistance, but easy to react with alkaline slag.

Uses: Mainly used in thermal equipment such as coke ovens, glass melting furnaces, acidic steelmaking furnaces, etc.

2. Alkaline refractory materials

Magnesium bricks: The main component is magnesium oxide, which is resistant to high temperature and alkali, and has excellent resistance to slag erosion.

Lime bricks: Made of quicklime, converted into calcium oxide, mainly used in blast furnace linings.

Magnesium-chrome bricks, chrome-magnesia bricks, magnesia-alumina bricks, dolomite bricks, forsterite bricks, etc.

Main components: mainly magnesium oxide (MgO) or calcium oxide (CaO).

Features: High refractoriness and strong ability to resist alkaline slag.

Uses: Mainly used in alkaline steelmaking furnaces, non-ferrous metal smelting furnaces and cement kilns.

3. Neutral refractory materials

Chrome bricks: Chromium-containing materials, resistant to high temperature and corrosion, mainly used in steel smelting and other industries.

Mullite bricks: Mullite is the main component, made of clay ore through high temperature sintering, with good thermal stability and strength, and the refractoriness is generally between 1200~1400℃.

Zirconium refractory materials: excellent high temperature resistance, good chemical stability, suitable for special occasions such as papermaking and aerospace.

High-aluminum refractory materials: made from bauxite, with high aluminum content and high refractoriness, suitable for high temperature areas of high temperature furnaces.

Features: It is not easy to react significantly with acidic or alkaline slag at high temperatures.

Uses: Widely used in the linings of various high-temperature furnaces, such as steel smelting furnaces, ceramic kilns, etc.

Classification by shape and preparation process

1. Refractory bricks

Features: The most common form of refractory materials, with good strength and corrosion resistance.

Uses: Widely used in the linings of blast furnaces, industrial furnaces and other equipment.

2. Refractory coatings

Features: Coating materials made of refractory particles and binders can improve the refractory performance of the lining and reduce heat loss.

Uses: Used to brush on the surface of the lining to improve the refractory and service life of the lining.

3. Refractory castables

Features: Mix refractory particles with cement, gypsum and other binders, cast and mold, and use them for repairing the lining of high-temperature furnaces.

Use: Used to repair and reinforce the lining of high-temperature furnaces.

4. Ceramic fiber

Features: The fibrous material formed by high-purity bauxite as raw material and high-temperature treatment has excellent thermal insulation and fire resistance.

Use: Widely used in high-temperature insulation and protection, such as the insulation layer of kilns and heat pipes.

5. Amorphous refractory materials

Features: A mixture composed of refractory aggregates and powders, binders or other additives in a certain proportion, which can be used directly or after adding appropriate liquids.

Types: furnace repair materials, refractory ramming materials, refractory castables (different from the previous refractory castables, this is a broader concept, including various forms of amorphous refractory materials), refractory plastics, refractory mud, refractory gunning materials, refractory projection materials, refractory coatings (similar to the previous refractory coatings, but a type of amorphous refractory materials), lightweight refractory castables, etc.

Uses: used for lining repair, thermal insulation, etc. of various high-temperature equipment.

Special refractory materials

1. Casting refractory materials

Features: Refractory products with a certain shape are cast after the batch is melted at high temperature by a certain method.

Uses: Used to manufacture special parts of high-temperature equipment, such as the taphole of blast furnaces and the mouth of steelmaking furnaces.

2. Carbonaceous refractory materials

Features: Mainly made of carbon materials, with high conductivity and high temperature resistance, but easily oxidized in a strong oxidizing environment.

Uses: Widely used in electric arc furnaces, and also used to manufacture the lining of high-temperature reactors, etc.

3. Special refractory materials

Features: New inorganic non-metallic materials developed on the basis of traditional ceramics and general refractory materials, with special physical and chemical properties.

Types: Such as silicon nitride combined with silicon carbide bricks, nitrides, silicides, sulfides, borides, carbides and other non-oxide refractory materials.

Uses: Used to manufacture special parts of high-temperature equipment and special applications in high-temperature environments, such as thermal protection systems of spacecraft, shielding materials for nuclear reactors, etc.

In summary, there are many types of refractory materials, each of which has its own unique composition, characteristics and uses. When selecting refractory materials, it is necessary to determine the appropriate material type according to the specific use environment and requirements.