The refractory bricks at the bottom of the glass furnace melting pool, as a key part to support the furnace structure and maintain the temperature stability of the melting pool, have withstood multiple tests such as high temperature, chemical erosion and physical impact for a long time. Over time, the refractory bricks will gradually erode, affecting the proper operation of the furnace and the quality of the glass. This article will elaborate on the erosion process of refractory bricks at the bottom of the glass furnace melting pool, and discuss its influencing factors and response strategies.
First of all, we need to understand the basic composition and working environment of refractory bricks at the bottom of the glass furnace melting pool. Refractory bricks are usually made of high-temperature materials such as high-aluminum, silica or zirconium, and have excellent high-temperature resistance and corrosion resistance. During the glass production process, the temperature of the molten pool is usually as high as over 1400°C. Alkaline oxides, acidic oxides and other impurities in the glass liquid will corrode the refractory bricks.
The erosion process of refractory bricks at the bottom of the glass furnace melting pool is a complex and slow process. During the operation of the furnace, the refractory bricks are first affected by high temperature, and their surface gradually oxidizes and sinters, forming a dense oxide layer. However, as the erosion progresses, this oxide layer is gradually destroyed, exposing the internal brick structure. At this time, the corrosive substances in the glass liquid begin to react chemically with the components in the brick, causing the brick to gradually dissolve and destroy.
In terms of chemical attack, alkaline oxides are one of the main factors in the corrosion of refractory bricks. Alkaline oxides react with the alumina and silica in the refractory bricks to produce low-melting substances that flow in the molten pool and erode the surface of the refractory bricks. In addition, acidic oxides will also corrode refractory bricks. Although their erosion rate is relatively slow, long-term accumulation will also cause significant damage to refractory bricks.
In addition to chemical corrosion, physical corrosion is also an important factor in the corrosion of refractory bricks. The scouring and abrasion caused by the flow of molten glass in the molten pool will continuously destroy the surface structure of the refractory bricks and accelerate their erosion process. At the same time, bubbles and impurities in the molten pool will also cause impact and wear on the refractory bricks.
The bottom of the glass melting furnace mostly adopts a multi-layer structure and has good insulation, which greatly reduces heat loss. The temperature of the bottom of the tank increases by about 200°C, which reduces the viscosity of the glass liquid there and intensifies the flow, which also strengthens the protection of the bottom of the tank. Scour and erosion. Not only that, the glass liquid can easily penetrate into the joints of poorly sealed bricks, interact with the refractory material to generate bubbles, form a three-phase interface condition, and cause upward undercutting.
The impurity iron brought in with the batch materials and broken glass when adding materials will cause more serious erosion; especially at the joints of bricks, bubbles will be generated after the impurity iron invades the joints or pores of the bricks, eroding holes in the bottom of the pool, and reacting with the glass liquid to refractory The upward undercutting produced at the material contact surface is similar.
The erosion of the bottom of a modern glass melting furnace comes from two aspects: first, direct erosion of the parts that are in contact with the glass liquid; second, erosion of the lower sealing layer (lining), causing damage to the bottom bricks.
The entire erosion process is divided into four stages: glass liquid or impurities penetrate from the brick joints; the sealing layer begins to be damaged; the foaming glass liquid penetrates into the space between the paving bricks and the lining at the bottom of the pool; "upward drilling corrosion" occurs, causing the pool bottom pavement to Facing tiles damaged.
Therefore, the iron oxides in the glass raw materials are controlled to the lowest allowable limit. Especially for silica sand with a large dosage, the iron oxide content is required to be less than 0.2%.
As the erosion continues, the performance of the refractory bricks gradually decreases, and its strength and corrosion resistance decrease, leading to problems such as increased temperature fluctuations in the molten pool and decreased glass quality. When the corrosion reaches a certain level, the refractory bricks may be damaged or fall off, seriously affecting the normal operation of the furnace.
In order to deal with the corrosion problem of refractory bricks, the following measures can be taken: first, select high-quality refractory brick materials to improve their high temperature resistance and corrosion resistance; secondly, optimize the furnace operation process to reduce the temperature of the melt pool and the content of corrosive substances; In addition, the refractory bricks should be inspected and maintained regularly to detect and deal with erosion problems in a timely manner; finally, advanced refractory brick protection measures should be adopted, such as spraying refractory paint, setting up protective layers, etc., to extend the service life of the refractory bricks.
In short, the erosion process of refractory bricks at the bottom of the glass furnace melting pool is a complex and slow process, which is affected by many factors. By understanding the erosion mechanism and influencing factors, we can take effective measures to slow down the erosion rate and extend the service life of the refractory bricks, thereby ensuring the normal operation of the furnace and the quality of the glass.
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