Corundum is a kind of polycrystalline alumina material. Alumina is one of the main components of the earth's crust, which has the advantages of abundant resources, relatively cheap and easy to obtain. Corundum has high temperature resistance, high strength, high hardness, electrical insulation, corrosion resistance and other physical and chemical properties. Therefore, corundum has become a widely used refractory material.

The melting point of corundum is as high as 2050°C. The fire resistance of corundum products is greater than 1900°C, the load softening starting temperature is about 1850°C, the limit use temperature is 1950°C, and the long-term use temperature is 1800°C. However, the coefficient of thermal expansion of corundum is 8.SXKr6TT1, which belongs to the medium and low thermal shock resistance of the material. With a hardness of 9, corundum is a high-hardness mineral, only lower than only lower than diamond and a few synthetic minerals. Alumina product strength is high, room temperature compressive strength up to 2000mpa; The bending strength at room temperature can reach more than 250mpa, and the bending strength can reach 150mpa at 100ctc. High-density alumina products can better resist the corrosion of iron, aluminum, nickel, vanadium and other molten metals; At room temperature, it is not corroded by sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, but at high temperature, sodium fluoride and concentrated sulfuric acid have a certain erosion effect on alumina. Alumina has certain resistance to the erosion of glass and slag.

Corundum alumina refractory castable has high compressive strength, excellent high temperature function, stable volume, small heat transfer coefficient, strong slag hydrophile resistance, corrosion resistance and wear resistance, convenient construction, comprehensive furnace wall structure, no H2.CO and other combustible substances recovery hazards, is a circulating system fluidized bed boiler in large and medium-sized power plants. High temperature kiln. Ideal high strength fireproof material wear-resistant products for metallurgical industry.
This product should use white corundum or iron oxide as fireproof material stone, plus various ultrafine powder and calcium aluminate concrete fusion agent, according to the proportion of high-end amorphous refractory insulation materials to be mixed.
Corundum refractory casting material with fused tube white corundum or iron oxide as fireproof material stone, plus a variety of ultrafine powder and calcium aluminate concrete fusion agent, according to the proportion of high-end amorphous refractory insulation materials, adjust the stone particles, improve the fusion agent, improve the refractory casting characteristics, the overall application of the actual effect is strong.

Characteristics of corundum refractory castable
1. High impact toughness in high temperature natural environment,
2. Good wear resistance. Good corrosion resistance.
3. High temperature volume reliability.
4. Strong antioxidant working ability.
The main uses of corundum refractory casting materials: mainly used in the lining of various high-temperature furnaces and high-temperature prefabricated components, such as rotary kiln front kiln, coal injection pipe, molten steel vacuum pump degassing device, metallurgical industry and argon integral paint gun lining, heating furnace top triangle lining, LF furnace cover, energy industry catalytic reaction cracked tube reactor high temperature wear-resistant lining.
Corundum refractory castable processing process:
Material selection - seasoning - mixing - bagging - storage.
1. Select the raw materials for making corundum refractory castable according to the secret recipe.
2. Proportionally configure the original configuration to manipulate the corundum refractory castable stone. Particle Indicates the particle size.
3. First stir the configured particles, then stir the stone, and then pour the particles into the stone for 8-12 minutes.
4. Mixed corundum refractory castable is packed into tonnage bag, equipped with preservative and fusion agent, and then sealed.
5. Store packed corundum refractory castable in the warehouse, and make time mark and waterproof and moisture-proof solutions.
Corundum refractory castable engineering construction method:
According to the main use, choose the construction method, flow casting or vibration casting. Today, people take vibration pouring as an example, first pour the mixed refractory pouring material into the abrasive tool, and then put the vibrator into the refractory pouring material and start to vibrate. After the surface of the refractory casting material is returned to the slurry, it is slowly removed, and the same part cannot be vibrated for a long time.
Corundum refractory castable project construction common problems:
1. Pour the dry ingredients into the blender and blend for 2 minutes.
2. Add water according to the actual use, and strictly control the water requirement.
3. The mixed slurry is recommended to grasp the material and join the group without water leakage.
4. Pay attention to the construction temperature, select heating or temperature reduction countermeasures if necessary, and ensure that the construction temperature is specified.
5. The prepared refractory castable needs to be used several times, and the solidified castable can not be used again.
6. Prevent the incorporation of dirt and harm the construction quality.
Common problems of corundum refractory castable in engineering construction.
Corundum refractory casting material should be made of corundum as stone and particle material, and add some fusion agent. It has excellent aluminum refractory casting material and mullite refractory casting material with high impact toughness and cavitation resistance, but slightly weak heat shock resistance. It is mainly used for lining raw materials of furnace such as heating furnace, hot blast furnace, hot blast furnace and porcelain kiln.
Inspection of corundum refractory castable before construction:
(1) Check the surface and cleaning of the mechanical equipment to be poured, and stipulate the cleaning of the construction surface.
(2) Check the intact state of engineering construction machinery, mixing, vibration strength special tools and other intact accessories.
(3) Check the appearance, specifications, layout and welding quality of the anchor parts, and do a good job of expansion compensation for the metal anchor parts (asphalt or other countermeasures).
(4) Check the application of surrounding corundum bricks and the lining and insulation board of related refractory bricks to prevent moisture in corundum refractory castables.
(5) Check the packaging and production date of corundum refractory castable, and conduct a pre-test to check whether it is invalid.
(6) Check the tap water in the construction of the project, and the water body exceeds the standard of domestic water. Therefore, when the new project inspection fails, the qualified side should be solved before the construction of the project. Corundum refractory casting material that is invalid at expiration shall not be used. Corundum refractory casting material construction site should ensure constant power, can not terminate the project construction.
Common problems in engineering construction
(1) Formwork: corundum refractory casting material construction formwork can use thick steel plate or rosewood (plywood), the formwork should have sufficient compressive strength, good stiffness, no shape, no movement, no leakage, rigid formwork should be coated with defilm agent, wood formwork should be coated with waterproof paint, the same formwork should be cleaned first, and then paint can be applied. Maintenance and cleaning holes are made of wood for standard mold shells. The metal material of the support point wood magic board should press more than 4 legs per square meter (to avoid obvious heat conduction), and the press leg should be welded with the anchor part as the basic welding (that is, the template press leg should be welded on the anchor part).
(2) Concrete water-cement ratio: When mixing corundum refractory pouring materials, the instructions should be strictly followed and the operation should not exceed the limit. On the premise of ensuring the characteristics of the construction of the project, less water should be added and more water should not be added.
(3) Mixing: the mixing time of corundum refractory pouring material should be greater than 5 minutes (calculated according to the instructions), and the forced mixer is used in actual operation. When stirring, dry stir first, then add 90% water to stir, and then slowly add the remaining water to stir again according to the wet zone level until it reaches the appropriate working level. Mixing different corundum refractory pouring materials should be cleaned in blender.
(4) Application of corundum refractory castable: Corundum refractory castable is used in the whole bucket and bag, and the mixed corundum refractory castable is used up in 40 minutes. This time, it should also be appropriately reduced in the natural environment of high temperature and dry work. Corundum refractory castable that has already condensed or even clumped shall not be poured into the mold frame or mixed with water.
(5) Vibration: When corundum refractory castable is poured into the mold frame, vibrator levels should be used first, the height width ratio should not exceed 400mm, and the vibration interval should be about 350mm. When vibrating, minimize contact with the anchor, do not damage the heat insulation plate, and do not vibrate or revive in the same part for a long time.