Measures to improve the life of electric arc furnace lining



1. Selection of refractory materials.

Refractories for furnace building have strict standards for alumina content, bulk density, compressive strength at room temperature, flexural strength at high temperature and apparent porosity. Magnesia carbon brick has the characteristics of good corrosion resistance, good high temperature strength, long service life, etc., and is widely used in the construction of furnace linings.

2. Masonry of furnace lining.

The furnace lining must be of good quality. When laying bricks of various types of road linings, attention should be paid to leveling, the brick gaps should be controlled at 2-3mm, and the furnace door and steel tapping should be built in strict accordance with the requirements. In the early days, the furnace body mostly used air hammer to tie the tar magnesia lining as a whole. The working conditions of the workers were poor. At the same time, the lining had low bulk density, large apparent porosity, poor resistance to slag erosion and erosion, and severe slag line erosion during the smelting process. After switching to tar-magnesia sand combined brick masonry, not only the production process is mechanized and automated, and the bulk density is also increased from 2.3 to above 2.8. The slag erosion and erosion resistance are greatly improved, especially in the slag line and tapping. Near the mouth, the anti-erosion ability is obviously enhanced.

3. Reasonably determine the diameter of the pole center circle of the electrode.

The life of the furnace lining has a great relationship with the distribution of the electrode center circle (the circle made by the center of the electrode hole in a regular triangle). The diameter of the electrode center circle determines the electrode distribution position and the power distribution of the three-phase electrode, which has a greater impact on the melting rate of the charge and the life of the furnace lining. Increase the diameter of the pole center circle of the electrode, the electrode is close to the furnace wall, and the furnace lining will accelerate the corrosion rate under the high temperature of the arc, and the heating of the charge in the middle of the furnace body will be weakened; reduce the diameter of the pole center circle of the electrode, the steel material in the middle of the furnace body will be easier Local high temperature is generated, and the melting rate of the charge on the slope slows down. According to the experience of steel mills, when the diameter of the electrode circle is equal to 0.35-0.39 of the diameter of the melting chamber at the level of the furnace door, the life of the furnace lining is the best, and the minimum coefficient is used when the diameter of the melting chamber of the electric furnace is larger.

4. Optimize and strictly enforce the operating rules.

The life of the furnace lining is related to many factors and is closely related to the smelting operation. Incorrect smelting operation will shorten the life of the furnace lining. Including the strict power supply system to control the temperature of molten steel, charge processing and charging, popularize the foam slag process, rationally organize production, and shorten the smelting time.

5. Maintenance of furnace lining

Add an appropriate amount of light-burned dolomite to the charge to increase the MgO content in the slag, and increase the alkalinity of the slag to reduce the erosion of the furnace lining. Furnace repair is an important part of improving the life of the furnace lining, which can effectively reduce the loss of the furnace lining. Generally, the dry gunning method is adopted. After tapping, take the time to strengthen the gunning for severely corroded parts such as both sides of the furnace door, tapping mouth, and No. 2 slag line. Gunning mending is based on the principles of uniform mending, quick mending, and thin mending to improve the adhesion rate of gunning material, reduce heat loss, achieve good sintering effect and reduce furnace lining erosion. When there is a large area of potholes at the bottom of the furnace, the wet patch method is used, and brine or water glass is used as the adhesive. Timely maintenance of the furnace lining can effectively extend the furnace life.

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