The ladle is responsible for the dual tasks of carrying molten steel and refining outside the furnace. The temperature of the molten steel in the ladle ranges from about 1550 to 1620°C, and the ladle must withstand the impact of severe cold and heat during service. Since the use conditions of the refining ladle are extremely harsh, the arc erosion of the slag line and ladle wall is very serious, resulting in premature damage to the refractory material and becoming the main reason that restricts its service life. Therefore, the requirements for ladle brick lining are higher than those for molten iron ladle brick lining.
The first part is the working layer. The working layer is in direct contact with molten steel and slag during ladle smelting. It is eroded by molten steel and steel slag, and is susceptible to large temperature differences. Therefore, the refractory materials used in the working layer are often seriously damaged and require regular checking and replacement. This layer generally uses aluminum-magnesium carbon bricks. In order to improve the service life of the ladle, the refractory materials in key parts such as ladle slag line bricks, purging plugs, sliding plates and nozzles should be kept synchronized with the ladle lining life.
The second part is the permanent layer, with a thickness of 30-60mm. The permanent layer is inside the working layer. The permanent layer plays the main role of the ladle. It plays a vital role in preventing leakage of molten steel and maintaining the safe operation of the ladle. Therefore, the The service life is related to the quality of this layer. The permanent layer generally uses corundum spinel castable, which has good resistance to slag erosion and penetration and excellent spalling resistance, and can well resist the above corrosion. At present, the service life of permanent lining is about 1.5-2 years.
The third is the insulation layer. The insulation layer is the outer layer of the lining, close to the steel plate, and has a thickness of about 11-15mm. The main function of the insulation layer is to insulate the molten steel, reduce the heat loss of the molten steel, and reduce the steelmaking energy consumption.
The sliding nozzle is composed of an upper nozzle, an upper slide plate, a collect nozzle and a lower slide plate. During the operation, the movement of the lower slide plate can be used to adjust the overlap of the upper and lower injection holes to control the flow. There are two adjustment methods, namely hydraulic mode and manual mode. Since the sliding nozzle has to withstand the erosion of high-temperature steel slag, the static pressure of molten steel, and the effects of rapid cooling and heating, the refractory material is required to be resistant to high temperatures, erosion, rapid cooling and heating, good slag resistance, and have sufficient high-temperature strength.
| Item | Magnesia carbon brick | Magnesia-alumina--carbon brick | Alumina-magnesia-carbon brick | Magnesium aluminum spinel castable | Ladle upper and lower nozzle brick | Ladle nozzle seat brick |
| Al2O3；% | / | / | ≥75 | / | / | ≥90 |
| MgO；% | ≥80 | ≥75 | / | / | / | / |
| Al2O3+MgO；% | / | ≥80 | ≥80 | ≥85 | / | / |
| C；% | ≥5 | ≥5 | ≥5 | / | / | / |
| ZrO2 | / | / | / | / | ≥70 | / |
| Apparent porosity；% | ≤4.0 | ≤5.5 | ≤7 | / | ≤22 | ≤24 |
| Bulk density；g/cm3 | ≥3.1 | ≥3.05 | ≥3.2 | ≥2.85 | ≥3.8 | ≥2.95 |
| Cold crushing strength；Mpa | ≥40 | ≥50 | ≥60 | ≥20 | / | ≥60 |
| Application | slag line | slag line | Ladle wall and bottom | permanent layer | Ladle bottom | Ladle bottom |
Hot blast stove
Refractory materials for casting
Refractory materials for Blast furnace
Coking
Pretreatment of Liquid Iron
