What refractory materials are generally used in steelmaking furnaces in steel mills?

I don’t quite understand it either, so I helped look into it; I hope it can be helpful. There are many types of refractory materials for steelmaking furnaces, which are divided into acidic refractory materials and alkaline refractory materials. Most of them are oxides with very high melting points. Silicon dioxide, found in acidic refractory materials, can withstand high temperatures of up to 1700 degrees Celsius ； Magnesia-carbon bricks, which are alkaline refractory materials, can withstand high temperatures of over 2000 degrees. The temperature for steel manufacturing is usually around 1600 degrees. The refractory materials in tube steelmaking furnaces are very thick; they are also corroded and worn away by the high-temperature molten steel during use. Special machines are required to spray refractory material onto the damaged areas for repair, and these materials have a limited service life.

I found some information; let’s learn about it together! Refractory materials: Inorganic non-metallic materials with a refractoriness of over 1580°C. Refractoriness refers to the Celsius temperature at which a conical sample of refractory material can resist the effects of high temperatures without softening or melting, in the absence of any load. Refractory materials emerged alongside high-temperature technology, roughly originating in the middle of the Bronze Age. During the Eastern Han Dynasty in China, clay-based refractory materials were already used as kiln materials and molds for firing porcelain. At the beginning of the 20th century, refractory materials evolved toward higher purity, greater density, and products capable of withstanding ultra-high temperatures. At the same time, non-shaped refractory materials that required no firing and had low energy consumption, as well as refractory fibers, emerged. In modern times, with the development of nuclear energy technology, space technology, and new energy technologies, refractory materials with excellent comprehensive properties such as high-temperature resistance, corrosion resistance, thermal shock resistance, and erosion resistance have been put into use. 　　There are many types of refractory materials, which are generally classified according to their refractoriness into ordinary refractory materials (1580–1770°C), advanced refractory materials (1770–2000°C), and super-grade refractory materials (above 2000°C) ； Based on their chemical properties, they are classified into acidic refractory materials, neutral refractory materials, and alkaline refractory materials. In addition, there are also fire-resistant materials for special occasions. 　　Acid-resistant refractory materials are primarily composed of silicon oxide, with silica bricks and clay bricks being the most commonly used ones. Silicon bricks are siliceous materials with a silicon oxide content of over 93%; their raw materials include silica and used silicon bricks. They exhibit strong resistance to corrosion by acidic slags, a high temperature at which they begin to soften under load, and no volume contraction even after repeated calcination, with slight expansion occurring instead ； However, it is susceptible to erosion by alkaline slag and has poor resistance to thermal shock. Silicon bricks are mainly used in thermal equipment such as coke ovens, glass melting furnaces, and acid steelmaking furnaces. Clay bricks are made primarily from refractory clay and contain 30% to 46% aluminum oxide; they are weakly acidic refractory materials with good resistance to thermal shock and corrosion resistance against acidic slag, making them widely used. 　　Neutral refractory materials are primarily composed of alumina, chromium oxide, or carbon. Corundum products with over 95% alumina content are high-quality refractory materials with a wide range of applications. Chromium bricks, whose main component is chromium oxide, exhibit good corrosion resistance to steel slag, but have poor resistance to thermal shock and a low deformation temperature under high-temperature loads. Carbon-based refractory materials include carbon bricks, graphite products, and silicon carbide products. They have a very low coefficient of thermal expansion, high thermal conductivity, good resistance to thermal shock, high strength at high temperatures, resistance to corrosion by acids, alkalis, and salts, are not wetted by metals or slag, and are lightweight. It is widely used as a lining material for high-temperature furnaces, as well as in the reactors of the petroleum and chemical industries. 　　Alkaline refractory materials are primarily composed of magnesium oxide and calcium oxide, with magnesia bricks being the most commonly used. Magnesia bricks containing 80% to 85% or more magnesium oxide exhibit excellent resistance to alkaline slags and iron slags, and have a higher refractoriness than clay bricks and silica bricks. It is mainly used in open-hearth furnaces, oxygen-blown converters, electric furnaces, non-ferrous metal smelting equipment, as well as some high-temperature equipment. 　　Refractory materials used in special applications include high-temperature oxide materials such as alumina, lanthanum oxide, beryllium oxide, calcium oxide, zirconium oxide, etc., as well as refractory compound materials such as carbides, nitrides, borides, silicides, and sulfides ； High-temperature composites mainly include cermets, high-temperature inorganic coatings, and fiber-reinforced ceramics. 　　Overview of refractory materials: Refractory materials generally refer to inorganic non-metallic materials with a fire resistance temperature of over 1580°C. They include natural ores as well as various products manufactured through specific processes to meet certain requirements. Possessing certain high-temperature mechanical properties and good volume stability, they are essential materials for various high-temperature equipment. 　　Types of refractory materials: 1. Acidic refractory materials generally refer to those with a SiO2 content of over 93%. Their main characteristic is their ability to resist erosion by acidic slags at high temperatures, but they tend to react with alkaline slags. Commonly used acidic refractory materials include silica bricks and clay bricks. Silicon bricks are siliceous materials with a silicon oxide content of over 93%; their raw materials include silica and used silicon bricks. They exhibit strong resistance to corrosion by acidic slags, a high temperature at which they begin to soften under load, and no volume contraction even after repeated calcination, with slight expansion occurring instead ； However, it is susceptible to erosion by alkaline slag and has poor resistance to thermal shock. Silicon bricks are mainly used in thermal equipment such as coke ovens, glass melting furnaces, and acid steelmaking furnaces. Clay bricks are made primarily from refractory clay and contain 30% to 46% aluminum oxide; they are weakly acidic refractory materials with good resistance to thermal shock and corrosion resistance against acidic slag, making them widely used. 　　2. Alkaline refractory materials generally refer to refractory materials whose main components are magnesium oxide or a combination of magnesium oxide and calcium oxide. These types of refractory materials have high fire resistance and strong ability to resist alkaline slag. Such as magnesia bricks, magnesia-chromium bricks, chromium-magnesia bricks, magnesia-alumina bricks, dolomite bricks, forsterite bricks, etc. It is mainly used in basic steelmaking furnaces, non-ferrous metal smelting furnaces, and cement kilns. 　　3. Aluminum silicate refractory materials refer to refractory materials whose main components are SiO2 and Al2O3. Based on their Al2O3 content, they can be classified into three categories: semi-siliceous (Al2O3 15–30%), clay-based (Al2O3 30–48%), and high-alumina (Al2O3 greater than 48%). 　　4. Cast refractory materials refer to refractory products of certain shapes that are produced by melting a mixture at high temperatures and then pouring it. 　　5. Neutral refractory materials refer to refractory materials that do not readily react significantly with acidic or alkaline slags at high temperatures, such as carbon-based refractory materials and chromium-based refractory materials. Some also classify high-alumina refractory materials in this category. 　　6. Special refractory materials are new types of inorganic non-metallic materials that have been developed on the basis of traditional ceramics and conventional refractory materials. 　　7. Amorphous refractory materials are mixtures composed of refractory aggregates and powders, binders, or additional admixtures in certain proportions; they can be used directly or after being mixed with an appropriate liquid. Amorphous refractory materials are a new type of refractory material that does not require calcination, with a fire resistance of at least 1580°C. 　　Commonly used ordinary refractory materials include silica bricks, semi-silica bricks, clay bricks, high-alumina bricks, magnesia bricks, etc. 　　Commonly used special materials include AZS bricks, corundum bricks, directly bonded magnesia-chromia bricks, silicon carbide bricks, silicon nitride-bonded silicon carbide bricks, as well as non-oxide refractory materials such as nitrides, silicides, sulfides, borides, and carbides ； Refractory materials such as calcium oxide, chromium oxide, aluminum oxide, magnesium oxide, beryllium oxide, etc. Commonly used thermal and fire-resistant materials include diatomite products, asbestos products, insulation boards, etc. Commonly used amorphous refractory materials include furnace repair materials, refractory ramming materials, refractory castables, refractory plastic compounds, refractory mortars, refractory spray repair materials, refractory projection materials, refractory coatings, lightweight refractory castables, and gunning mixes. 　　The physical properties of refractory materials include structural properties, thermal properties, mechanical properties, service properties, and handling properties. 　　The structural properties of refractory materials include porosity, bulk density, water absorption, air permeability, and pore size distribution. 　　The thermal properties of refractory materials include thermal conductivity, coefficient of thermal expansion, specific heat, heat capacity, thermal diffusivity, thermal emissivity, etc. 　　The mechanical properties of refractory materials include compressive strength, tensile strength, flexural strength, torsional strength, shear strength, impact strength, wear resistance, creep resistance, bond strength, elastic modulus, etc. 　　The performance characteristics of refractory materials include refractoriness, load softening temperature, reflow line change, thermal shock resistance, slag resistance, acid resistance, alkali resistance, hydration resistance, CO erosion resistance, electrical conductivity, oxidation resistance, and more. 　　The workability of refractory materials includes consistency, slump, fluidity, plasticity, adhesiveness, resilience, setting time, hardening properties, etc. 　　(Reference: http://www.fm086.com/Article/Article.asp?id=77779)

It depends on whether it is used in steel mills, where high requirements are placed on the refractory materials for converters, refining furnaces, or tundishes within the steel mill processes. The refractory materials used in different sections of each furnace also vary. Of course, both the steelmaking process and the type of furnace require consideration when selecting refractory materials of different types. What you said is too general; it would be better if you could be more specific