What are the types of commonly used ladle refractories?

1) Clay bricks, the content of A12O3 in clay bricks is generally between 30%-50%, which is low. It is mainly used for ladle permanent layer and ladle bottom.

2) High alumina bricks. The content of A12O3 in bricks is between 50%-80%, which is mainly used in the working layer of the ladle.

3) Wax stone bricks. The brick is characterized by a high SiO2 content. Generally, it is more than 80%, which is better than the erosion resistance and integrity of clay bricks, and does not hang slag. It is commonly used for ladle walls and ladle bottoms.

4) Zircon bricks. The brick is mainly used for the ladle slag line part. The ZRO2 content in bricks is generally between 60%-65%.

5) Magnesia carbon bricks. The brick is mainly used for ladle slag line parts, especially suitable for multi-furnace continuous pouring occasions. The MGO content in bricks is generally about 76%, and the carbon content is between 15%-20%. It is characterized by low erosion to slag, good erosion resistance and spalling resistance.

6) Aluminum-magnesium castable. The castable is mainly used for steel ladle body, which is characterized by the reaction of MGO and A12O3 in the castable under the action of molten steel to form aluminum oval spinel, which improves the slag resistance of the lining and the thermal shock resistance.

7) Aluminum-magnesia-carbon bricks. This brick is a ladle lining developed on the basis of aluminum-magnesium castable, which has a long service life.

8) Do not burn bricks. At present, almost all the materials used for fired bricks in ladles can be made into corresponding unfired bricks. It is characterized by a relatively simple production process and low production process. The brick itself has a certain mechanical strength and erosion resistance, which is convenient for masonry.

If the ladle itself is also used for refining, you can also choose MGO-CR2O3-A10O3 series and MGO-CAO-C series refractories, mainly including: magnesia-chrome bricks, magnesia-chrome aluminum bricks, dolomite bricks, etc.

When using bricks with ink content as ladle lining, it is best to apply a layer of anti-oxidation coating on its surface to prevent oxidation and looseness on the surface of the lining when burning the ladle, which will affect its service life.

Large ladles are mainly made of magnesia carbon bricks, of course, there are intermediate layers (such as better high-alumina castables), thermal insulation materials, etc

Small ladles with aluminum-magnesium castables are enough!

The general category is classified as permanent layer and working lining.

The specific varieties are: breathable bricks (corundum), ladle bricks (magnesia-carbon or corundum), permanent layer castable (high alumina), bottom reinforcement material, tank edge repair material and so on.

1) Clay refractory bricks (2) High alumina refractory bricks.

1. Silica refractory. Silica refractory is a refractory with SiO2 as the main component and SiO2 mass fraction of not less than 93%, which can be shaped or unshaped. The refractory material has the advantages of thermal conductivity, high load softening point, and strong resistance to acid slag erosion, but the biggest disadvantage is low thermal shock stability.

Therefore, the refractory is mainly used as a structural material for coke ovens, glass melting furnaces, acid steelmaking furnaces and other thermal equipment.

2. Aluminosilicate refractories. Aluminosilicate refractories are refractories with Al2O3 and SiO2 as the main components. According to the different Al2O3 content in refractories, it can be divided into semi-siliceous (mass fraction 15% 30%), clay (mass fraction 30% 48%) and high alumina (mass fraction 48%) refractories.

The refractory has the advantages of light weight, thermal stability and good thermal insulation performance, but its starting deformation temperature is 1400. Therefore, aluminosilicate refractories are generally used as insulation materials in the metallurgical industry and are not used in working layers.

3. Magnesia refractory material. Magnesia refractories are refractories with chlorite-based crystal phase and MGO mass fraction greater than 80%. Affected by the composition of magnesia raw materials, the main components of magnesia refractories are MGO, FeO, Fe2O3, Al2O3, SiO2, Cao, with a melting point of up to 2800, and the refractory degree of magnesia refractory materials reaches 2000, so magnesia refractories have good high temperature resistance.

Magnesia refractories include magnesia bricks, forsterite refractories, magnesium-aluminum spinel refractories, magnesia-chromium refractories, and white jade refractories. Among them, magnesia-chromium refractories are made of magnesia and chromite, and magnesia is the main component. Compared with traditional magnesia bricks, magnesia-chromium refractories have stronger thermal stability and are widely used in non-ferrous smelting furnaces.

However, because hexavalent chromium has serious harm to the environment and human health, especially it will cause serious pollution to water, it is necessary to strictly control the alkaline medium and oxygen partial pressure in the production and production process.

4. Dolomite refractory materials. Dolomite refractory is an alkaline refractory with dolomite as the main raw material and MGO and CAO as the main components, in which the mass fraction of CAO is 40% 60%, and the mass fraction of magnesium oxide is 30% and 40%. The refractory temperature of dolomite refractory is above 1780, and the starting temperature of load softening is 1550, which shows that it has good high temperature stability.

Dolomite refractory material is a strong alkaline refractory material, which has strong slag resistance to alkaline slag, but has poor slag resistance to acid slag. Therefore, the refractory material is mainly used for open-hearth furnace walls and bottoms, rotary kiln firing belts, etc.

Refractories are divided into two categories: ordinary and special refractories.

1. Ordinary refractories refer to conventional products used in metallurgical furnaces, cement kilns, glass kilns and other thermal kiln linings, most of which are processed from natural raw materials. Ordinary refractories are divided into acidic, neutral, and basic according to their chemical properties.

2. Special refractories are new inorganic non-metallic materials developed on the basis of traditional ceramics and general refractories. The materials used in special refractories are of high purity, mostly oxides, compounds and high-temperature composite materials, and are used in special kilns, smelting blast furnaces and other special parts that are not prepared at high temperatures.

Commonly used refractories are:

1. Corundum bricks.

Corundum brick refers to refractory products with alumina content greater than 90% and corundum as the main crystalline phase. Very high compressive strength at room temperature (up to 340MPa). High load softening onset temperature (greater than 1700 °C).

It has good chemical stability and strong resistance to acidic or alkaline slag, metal and liquid glass.

2. Silicon carbide bricks.

Refractory products made of silicon carbide as the main raw material. Silicon carbide content 72% 99%. Generally, black silicon carbide (SiC content of more than 96%) is used as raw material, and binder (or no binder) is added, and it is prepared by batching, mixing, molding and firing.

1. According to the level of refractoriness:

Common refractories: 1580 degrees Celsius to 1770 degrees Celsius.

Advanced refractories: 1770 degrees Celsius to 2000 degrees Celsius.

Premium refractory material: more than 2000 degrees Celsius.

2. According to the manufacturing method, refractory materials can be divided into: fired products, unfired products, and unshaped refractories.

3. Classification according to the chemical properties of materials: acid refractories, neutral refractories, alkaline refractories.

4. Classification according to the composition of chemical minerals: This classification method can directly characterize the basic composition and characteristics of various refractory materials, and is a common classification method in production, use and scientific research, and has strong practical application significance.

5. Classification of amorphous refractory materials: castables, spray coatings, ramming materials, plastic, pressing materials, projection materials, and dry vibrating materials.

Magnesia, magnesia, aluminum, magnesium, carbon, zirconium refractories, special refractories.

A class of inorganic non-metallic materials with a refractory degree of not less than 1580. Refractory resistance refers to the Celsius temperature at which the refractory conical specimen resists high temperature without softening and melting without load.

However, the definition of refractory alone is no longer a complete description of refractories, and 1580 is not absolute. It is now defined as a material whose physical and chemical properties allow it to be used in a high-temperature environment, called a refractory material.

Refractories are widely used in metallurgy, chemical industry, petroleum, machinery manufacturing, silicate, power and other industrial fields, and are the largest in the metallurgical industry, accounting for 50% and 60% of the total output.

Refractory materials are used in various fields of the national economy such as steel, non-ferrous metals, glass, cement, ceramics, petrochemicals, machinery, boilers, light industry, electric power, military industry, etc., and are indispensable basic materials to ensure the production and operation of the above-mentioned industries and technological development, and play an irreplaceable and important role in the development of high-temperature industrial production.

Since 2001, under the strong pull of the rapid development of high-temperature industries such as steel, nonferrous metals, petrochemicals, building materials, etc., the refractory industry has maintained a good growth trend and has become a major producer and exporter of refractories in the world. In 2011, China's refractory production accounted for about 65% of the world's total, and its production and sales ranked first in the world.

Auxiliary raw materials can be divided into binders and additives. The function of the binder is to make the refractory body have sufficient strength during production and use. Commonly used are sulfurous acid pulp waste liquid, asphalt, phenolic resin, aluminate cement, water glass, phosphoric acid and phosphate, sulfate, etc., and some of the main raw materials themselves have the role of binders, such as binding clay; The role of additives is to improve the production or construction process of refractory materials, or to strengthen certain properties of refractory materials, such as stabilizers, water reducers, inhibitors, plasticizers, foaming agents, dispersants, expansion agents, antioxidants, etc.

In the past, clay was listed as an acidic raw material, which was not suitable. The acidity of refractory raw materials is based on free silica (SiO2), because according to the chemical composition of refractory clay and siliceous raw materials, there is much less free silica in refractory clay than siliceous raw materials. Because there is 30% 45% alumina in general refractory clay, and alumina is rarely in a free state, it must be combined with silica to form kaolinite (Al2O3·2SiO2·2H2O), even if there is a small amount of excess silica, the effect is very small.

As a result, refractory clays are much less acidic than siliceous raw materials. Some people believe that refractory clay decomposes into free silicic acid and free alumina at high temperatures, but this does not change from there, and when it continues to be heated, free silicic acid and free alumina will combine to form Enlaite (3Al2O3·2SiO2). Enlaiite has good acid resistance to alkaline slag, at the same time, due to the increase of alumina content in refractory clay, its acidic substance gradually weakens, when the alumina reaches 50%, it will appear alkaline or neutral properties, especially in the clay bricks made under ultra-high pressure, high density, fine and compact, low porosity, and the resistance to alkaline slag is stronger than silica under high temperature conditions.