01. Steel making system
The steelmaking system includes converter, electric furnace, off-furnace refining furnace, ladle and tundish and other equipment.
In the electric furnace, the dry vibrating material, the prefabricated or cast-in situ furnace cover or the triangle area of the furnace cover are all used with good results.
In the converter and electric furnace, the damage is generally repaired by fire-resistant spray paint, which includes manual repair, wet, dry or flame spraying and slag splashing.
In the converter, the slag splashing technology is generally used to protect the furnace, and the furnace age can reach more than 10,000 times.
There are many types of refining furnaces outside the furnace, and the inserted tube liner body of RH and DH degassing devices is generally poured into a whole with high aluminum refractory castable, and the service life is 20 to 80 times.
Ladle and tundish are the important auxiliary equipment of steelmaking furnace, and also the thermal equipment that consumes the most refractory materials. In the past, ladle was generally made of fired brick masonry such as clay refractory brick, high-aluminum refractory brick, semi-silicon brick and wax stone brick, with a service life of 10 to 70 times. When using ladle blowing or continuous ingot casting, due to high steel temperature and long residence time, the package age drops sharply. Therefore, countries attach great importance to the development of packaging materials and have made remarkable progress.
200t ladle used in converter of a steel plant is lined with aluminum-magnesium castable and free-flowing material. The ladle age is about 95 times and 80 times respectively.
The 300t ladle used in the converter of a steel plant is lined with high purity aluminum and magnesium castable. After repair, the ladle age is generally about 260 times, and the single consumption of refractory material is below 1.78kg.
Many steel mills in the country are not more than 100t ladle, with new technology aluminum magnesium refractory castable, its age is about 90 times, and the cost of pouring steel is 5.50 to 7.50 yuan per ton of steel.
The lining of the middle bag is made of insulation board or magnesia paint, and the slag weir is made of mullite, aluminum-magnesia and magnesia refractory castable, which can meet the technical requirements of continuous casting steel.
Integral spray gun for off-furnace refining, used for ladle slag blowing or ladle powder spraying, etc. The parts above the slag line are made of high aluminum refractory castable, and the parts from the slag line to the nozzle are made of low cement corundum refractory castable.
02. Iron making system
The ironmaking system includes sintering, coking and blast furnaces and their auxiliary equipment. Belt sintering machine ignition furnace with refractory plastic and clay combined refractory castable on site, or with phosphate refractory castable prefabricated block lifting, its service life is 3~6 years.
When the line ignition device is used, the top of the furnace is pressed down more, the working condition of the furnace becomes better, and the light and high strength refractory castable or refractory fiber and its products can be used as lining, and better results can be obtained.
The heat insulation layer, the coating layer and the door of the coke oven are poured with refractory castable. When the furnace head is damaged, it is repaired with spray paint. In addition, dry quenching equipment also uses heavy or light refractory castable;
Blast furnace is continuous production of iron making equipment. Small blast furnaces used to be mounted with aluminate cement and high alumina phosphate refractory castable prefabricated blocks, but now they are generally constructed with resin bond aluminum-carbon unfired bricks.
The large blast furnace water wall is rammed with silicon carbide castable, the furnace bottom cushion and the surrounding brick joints are filled with refractory castable and silicon nitride filler, and the furnace lining is repaired with refractory pressing material and refractory spray paint when it is damaged, so as to extend the service life and make the furnace age reach 10 or even 15 years.
The iron outlet of blast furnace is generally blocked with loose Al2O3-SiC C clay, which can ensure the stability of iron outlet and normal operation.
The blast furnace discharge groove was originally rammed with refractory ramming material, and the per-ton iron consumption of the groove material was about 1.1kg. Now with low porosity dense refractory casting, a one-time iron flow of about 100,000 t, a generation of gap age accumulated iron flow of about 900,000 t, resistant material per ton of iron consumption is less than 0.38kg. At the same time, the free flow refractory castable and non-baking refractory castable are also applied in the blast furnace iron hook.
The inner lining of medium and small blast furnace hot blast furnace is made of refractory castable precast block. The burners of hot blast furnaces can be masonry with refractory castable blocks or poured in situ, and the ball tops are poured with castable working lining. The body of the large hot blast stove relies on the light spray coating of the first layer of the shell with a volume density of about 1.3g/cm3, and the top of the ball is sprayed with a layer of acid-resistant spray coating to form the overall lining. Corundum refractory castable and other materials are used for on-site watering to obtain a good use effect. Torpedo type iron pot and iron mixer generally use fire-resistant castable in part or in whole, and can also be repaired with fire-resistant spray paint, and the use effect is better.
03. Building materials system
Building materials systems include industrial sectors such as cement, glass and ceramics.
Cement kiln lining with high aluminum phosphate or magnesium and magnesium chromium non-fired bricks, service life of 6 to 18 months, local also use amorphous refractory materials.
In a rotary kiln of a large cement plant, the amount of refractory castable is 19%~35%, the main varieties are low cement refractory castable, aluminate cement refractory castable, silicon carbide refractory castable and thermal insulation castable.
In the glass industry, the tin tank on the float glass production line is made of refractory castable. In addition, when the glass tank kiln is damaged, it is repaired with silica repair material. Silicone-insulated castable is generally used when the new pool kiln is insulated. Ceramic industry kiln, sometimes with silicon carbide refractory castable and light refractory castable.
04. Rolling system
There are many kinds and large quantities of industrial furnaces in the rolling system, and the operating temperature is generally below 1400℃, which are flame furnaces.
The kiln of the system can be lined with amorphous refractory materials, and good economic results have been obtained.
The rolling furnace is lined with refractory plastic, which has a long service life. Using clay combined with refractory castable as a whole to irrigate the lining, the service life is generally 4 to 10 years.
For regenerative heating furnace, the micro-expansion refractory castable should be selected as the lining, which has been used for more than 2 years and is intact. The forged steel heating furnace is generally intermittent operation, large temperature change and vibration, etc., with brick lining, the use of 2 to 5 months, with adhesive combined with refractory castable can be used for more than 2 years
As we all know, the use of steel rolling heating furnace temperature <1400℃ and intermittent operation, domestic and foreign production practice has proved that the lining material should be selected Al203≤65%, drying and 1400℃ after burning pressure strength of 20~25Mpa and not less than 60Mpa, you can achieve the purpose of longevity. Because of the high aluminum content and strength of the refractory castable, its thermal shock resistance is poor, easy to flake and crack when used, affecting its life.
05. Other industrial systems
In the petrochemical industry, lightweight refractory castable with a bulk density of 0.5 to 1.0g/cm3 for tubular heating furnaces is constructed by manual coating or spraying and has a service life of about 5 years.
The use of refractory spray coating for lining has also obtained better results. In particular, wear-resistant refractory castables have been applied in platinum reforming units, which can eliminate heat-resistant steel tortoise mesh system, and its life has also been improved.
Various conversion furnace lining, the use temperature is 600~1500℃, generally use aluminate cement refractory castable, low cement refractory castable and corundum castable, etc., service life of 3~6 years;
In the non-ferrous metallurgy industry, the thermal equipment such as lead-zinc closed blast furnace, flash furnace, electrolytic cell and rolling heating furnace are partially used with amorphous refractory lining.
Recently, anti-permeable refractory castables have been widely used in aluminum electrolytic cells, and satisfactory results have been obtained. In the lining of steam boilers, the use of amorphous refractory materials is the earliest and most common. Generally use aluminate cement heavy or light refractory castable, service life of about 10 years.
The high alumina, corundum and SiC refractory castables and refractory plastics used in fluidized bed power generation boilers have high strength and good wear resistance, which meet the design and use requirements. In addition, amorphous refractories are also used in machinery, fire resistance and waste incineration industries, and good results have been achieved.
