Classification of refractory materials
1. Acidic refractory materials usually refer to refractory materials with SiO2 content greater than 93%. Their main characteristic is that they can resist the erosion of acidic slag at high temperatures, but are prone to react with alkaline slag. The commonly used acidic refractory materials are silica bricks and clay bricks. Silica bricks are siliceous products containing over 93% silicon oxide, and are made from raw materials such as silica and waste silica bricks. They have strong resistance to acid slag erosion, high softening temperature under load, and do not shrink or even slightly expand after repeated combustion; But it is susceptible to erosion by alkaline slag and has poor thermal vibration resistance. Silicon bricks are mainly used in thermal equipment such as coke ovens, glass melting furnaces, and acid steelmaking furnaces. Clay bricks are mainly made of refractory clay and contain 30% -46% alumina. They are weakly acidic refractory materials with good thermal vibration resistance and corrosion resistance to acidic slag, and are widely used.
2. Alkaline refractory materials generally refer to refractory materials mainly composed of magnesium oxide and calcium oxide. These refractory materials have high refractoriness and strong resistance to alkaline slag. For example, magnesia brick, magnesia chrome brick, chrome magnesia brick, magnesia alumina brick, dolomite brick, magnesium olivine brick, etc. Mainly used for alkaline steel furnaces, non-ferrous metal smelting furnaces, and cement kilns.
3. Aluminum silicate refractory materials refer to refractory materials mainly composed of SQ2-AI2O3, which can be divided into three categories based on their AI2O3 content: semi silica, clay, and high alumina.
4. Melting and casting refractory materials refer to refractory products with a certain shape that are poured by melting the mixture at high temperature using a certain method.
5. Neutral refractory materials refer to refractory materials that are not easily reactive with acidic or alkaline slag at high temperatures, such as carbon refractory materials and chromium refractory materials. Some classify high alumina refractory materials as such.
6. Special refractory materials are a new type of inorganic non-metallic material developed on the basis of traditional ceramics and general refractory materials.
7. Amorphous refractory materials are a mixture composed of refractory aggregates, powders, binders, or other additives in a certain proportion, which can be used directly or mixed with appropriate liquids before use. Unstructured refractory material is a new type of refractory material that is not calcined, and its refractoriness is not less than 1580 ° C.
