Reasons for Damage of Converter Lining and Protective Measures
Converter smelting is a series of physical and chemical reaction processes under high-temperature conditions. In this process, the furnace lining is corroded by a series of strong mechanical, physical and chemical effects. The main reasons for the damage to the converter lining are as follows.
1. Mechanical impact erosion.
The operations of adding scrap steel and adding molten iron are directly directed to the lining of the converter. This has a strong impact, abrasion, and erosion on the large surface furnace lining, which is the main factor for the corrosion of the furnace lining refractory material.
2. Physical effects.
During the smelting process, the refractory lining of the converter is scoured and worn by high-temperature airflow and high-temperature solutions. For example, the scouring of refractory materials such as furnace walls and furnace caps by the airflow in the furnace; the melting and scouring of the furnace lining by molten steel and slag; and the softening and melting loss of the furnace lining caused by the high-temperature reaction during the smelting process.
3. Chemical action.
The working layer of the converter lining is generally made of magnesia carbon bricks. Magnesia carbon brick contains a certain amount of graphitic carbon, which has poor wettability with molten slag, which can hinder the penetration of molten slag into the brick body. Its thermal conductivity is good, and the thermal vibration resistance of the lining brick can be greatly improved so that the life of the magnesia carbon brick lining is longer. However, there is a strong oxidizing atmosphere in the converter furnace. In the smelting process, high-temperature oxidizing gas will oxidize and remove part of the carbon in the brick, causing the brick structure to become loose and brittle. Thus, it is lost and corroded under the scouring of smoke and fluid.
4. The furnace lining is peeling off.
The spalling of the lining brick caused by thermal vibration, and the spalling caused by the decomposition of the mineral composition of the lining brick itself.
Protection of Furnace Lining and Measures to Improve Furnace Lining Life
Improve the quality of masonry. The masonry quality of the converter lining is the foundation of the furnace age. First of all, the quality of furnace lining bricks (including specifications, dimensions, and performance) must be qualified. Then the furnace lining is laid in strict accordance with the technical requirements.
Optimize the smelting operation process. The composition of molten iron and the processing system all have an impact on the life of the furnace lining. For example, when the content of Si in the molten iron is high, the content of SiO in the slag is correspondingly high, and the corrosion and erosion of the furnace lining will also increase.
Strengthen furnace body maintenance. Slag splashing to protect the furnace is the main means of maintaining the furnace lining in daily production. But there are other maintenance methods based on the damage location and extent of the lining bricks. Maintenance of the furnace bottom is mainly based on repairing the furnace. First, determine the damage thickness, and then repair the furnace with the repair material. The repairing charge is magnesia cold repairing charge or repairing bricks. The charging surface of the furnace body can be maintained by a combination of gunning and charging materials. According to the damage condition, the tapping port shall be replaced as a whole or be pedested with a repairing charge. The trunnion and slag line can only be repaired by gunning.
As the saying goes, know yourself and the enemy, and you will win every battle. Only by understanding the causes of damage in the converter smelting process can we find a way to extend the service life of the refractory lining for the converter. Refractory brick manufacturers, through years of production and sales experience, provide high-quality refractory lining materials for various industrial furnace equipment. Please contact us for kiln refractory brick lining materials. Or send your refractory lining material requirements to our customer service mailbox, and we will provide you with refractory brick products that best suit your production needs according to your specific working conditions.
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