How to do EAF repair

 From the point of view of the furnace repair materials, there are dry repair and wet repair. The charging material is magnesia [w(MgO)>78%] or roasted dolomite, and tar (hydrocarbon) is used as a binder during dry repair. The binder used for wet repair is brine (MgCl2·xH2O) or water glass (Na2SiO4·yH2O), which is often used in the furnace lining where the damage is serious or the slope is large, and it is difficult to repair. The dosage ratio of asphalt and magnesia is about 1:10, and the dosage of brine, water glass or magnesia should be kneaded into a group and not loose.

Throw the furnace repair material to the eroded place, and sinter the furnace repair material and the furnace lining into a whole by the heat energy of the furnace lining. When the furnace is repaired with magnesia and asphalt mixture, the liquid asphalt is filled between the magnesia at high temperature, and decomposes and volatilizes, and what remains is fixed carbon, which is used as a skeleton to lock the magnesia particles into a whole. Carbon only volatilizes above 4000°C. When wet filling is used, the moisture of MgCl2·xH2O or Na2SiO4·yH2O is volatilized at high temperature, and MgO·MgCl2 compound is formed in the gap of magnesia, which plays the role of locking magnesia.

The principle of repairing furnace is high temperature, thin repair and quick repair. Minimize high-temperature radiation and heat dissipation, and operate quickly.

After tapping, immediately use a shovel to fill the two sides of the tapping hole and the furnace slope, so that the heat loss is less, and then use a large shovel to repair the two sides of the furnace door. Because the charging material depends on the residual temperature in the furnace for sintering, the faster the charging, the less heat loss in the furnace, and the higher the temperature, the better the sintering. After tapping, the door of the furnace and the tapping port are easily cooled by the cold air, and the slope of the tappin hole port is related to whether the molten steel can be fully poured (if the molten steel is not exhausted, the furnace bottom is easily damaged, and it is easy to use the next furnace. The chemical composition is unstable), so it is necessary to repair both sides of the furnace door and the steel outlet first. In order to avoid the residue sticking at the furnace slope, it is also possible to scrape it with an iron rake before repairing the furnace. The rest of the parts are relatively difficult to cool, and can be repaired after the two sides of the furnace door and the tapping hole brick are repaired. For the slag line and furnace slope near the three-phase electrode, due to the effect of the arc, there is more erosion, so pay attention to it. repair. It needs to be thinly filled, because it is too thick at once, and the inner layer of magnesia is poorly heated and cannot be sintered well, resulting in the floating of large pieces of magnesia during the smelting process and the viscosity of the slag, so the thickness of the furnace is generally not more than 25mm. When the amount of furnace repair is large, some lime can also be added to the dolomite magnesia to further protect the furnace body.

The time for repairing the furnace depends on the erosion situation and the capacity of the furnace, generally 3~5min.?We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality EBT taphole block are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:How to do EAF repair
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