Classification of Different Refractory Products

Refractory products can be divided into three categories: acid-base refractory materials, neutral refractory materials, and alkaline refractory materials. For example, the key component of acid-refractory materials is silica, and the iconic products are silica bricks and clay bricks.

Silica bricks are siliceous products containing more than 94% silicon. Its raw materials include silica and waste silica bricks. Acid-resistant slag is highly corrosive, has a high load softening temperature, and its volume does not approach or even slightly increase after repeated calculations. However, alkaline slag easily corroded it and has poor thermal shock resistance. Silica bricks are mainly used in thermal equipment such as coke ovens, glass furnaces, acid-base steelmaking furnaces, etc. Clay bricks use refractory clay as the main raw material, and the alumina content is 30%-46%. It is a weakly acidic refractory material with strong heat and shock resistance. Resistant to acid and alkali slag corrosion, widely used.

The main components of neutral refractory materials are aluminum oxide, chromium oxide, or carbon. High-alumina corundum products are high-quality refractory materials that are widely used. Chromium bricks with chromium oxide as the main component have good resistance to steel slag corrosion, but under high-temperature loads, their thermal shock resistance is weak and their deformation temperature is low. Carbon refractory materials include carbon bricks, graphite products, and silicon carbide products. It has the characteristics of a low linear expansion coefficient, good heat transfer performance, good high-temperature impact resistance, high-temperature resistance and strength, and acid, alkali, and salt corrosion resistance. Especially under the conditions of weak acid and weak alkali, it has good acid resistance and is not wetted by metal and slag. It is widely used as a high-temperature furnace lining material and can also be used as autoclave lining in petroleum, chemical, and other industries.

Magnesium oxide and calcium oxide are the main components of alkaline refractory materials and magnesia bricks are commonly used refractory materials. Magnesia bricks with a magnesium content of more than 80% to 85% have good resistance to alkaline slag and iron slag, and their fire resistance is higher than clay bricks and silica bricks. It is mainly used in open hearth furnaces, oxygen-blown converters, electric furnaces, non-ferrous metal smelting equipment, and some high-temperature equipment.

On the other hand, non-oxide refractory materials such as AZS bricks, corundum bricks, fused magnesia chromium bricks, silicon carbide bricks, silicon nitride fused silicon carbide bricks, nitrides, silicides, sulfides, borides, carbides, Calcium oxide, chromium oxide, aluminum oxide, magnesium oxide, beryllium oxide, etc. are also commonly used. Diatomaceous earth products, asbestos products, insulation boards, etc. are commonly used as thermal insulation refractory materials. Commonly used unshaped refractory materials include patching materials, refractory ramming materials, refractory castables, refractory plastics, refractory mud, refractory gunning materials, refractory castables, refractory coatings, lightweight refractory castables, gun mud, etc.