The ultra-fine powder of the batch material can easily cause flying materials during the glass melting process. The corrosion of refractory materials in the glass furnace mainly involves the chemical attack of flame gas, fly material, alkali vapor and glass liquid on the refractory materials in the furnace at high temperatures. The fly material mainly erodes the upper part of the furnace (including the large chute, breast wall, Various parts of the small furnace) and the regenerator. Among them, the regenerator is more serious, because the fly material is easily carried into the regenerator by the airflow in the kiln, erodes the regenerator, causes damage or blockage of the regenerator, and affects the heat exchange effect and service life. At present, alkaline bricks are generally used for the upper and middle layers of the better regenerator lattice bodies. The upper layer is mostly directly bonded with high-purity
magnesia bricks, and the middle layer is mostly directly bonded with magnesia-chrome bricks. Production practice shows that the main damage forms are chemical erosion and thermal stress damage. The main crystal phase of high-purity magnesia bricks is periclase. When the temperature is above 1430℃, periclase crystals will gradually grow up under the action of alkali steam. The volume change will cause cracks, breakage, powdering and peeling on the surface of the brick. At the same time, the SiO2 in the fly material will gradually enter the cracks and change the ratio of CaO/SiO2 in the matrix part, and then form a large amount of eutectic diopside (CMS2), magnesia sclerite (C2MS2), forsterite Substances such as stone (M2S) and magnesia rhodonite (C3MS2) have a large volume effect and accelerate the cracking, crushing, powdering and peeling of periclase.
If the V2O5 concentration in the flue gas composition is high, 3CaO·V2O5 (calcium aluminate) will be decomposed into low ettringue calcium, with the lowest eutectic point of 618°C, and it will be a liquid phase at the upper working temperature of the lattice, and will be weakly reducing Will evaporate. The formation of calcium aluminate changes the ratio of CaO/SiO2 in the magnesia brick on the one hand, and changes the stable range of the matrix to the eutectic range of the CaO-MgO-SiO2 ternary system; on the other hand, calcium aluminate ( The liquid phase) penetrates into the bricks, which will promote the growth of periclase crystals and cause the magnesia bricks to deform, crack, break, pulverize and peel off.
In addition, in the range of 950~1150℃, if V2O5 and SiO2 exist at the same time, when Na2O/SO3<1, a reaction will occur: harmful sulfates are generated, which accelerates the corrosion of magnesia bricks. The upper part of the grid is the easiest to contact Na2CO3, SiO2 in the flying material and V2O5 in the heavy oil. Therefore, the grid body is most vulnerable to erosion. In order to reduce the occurrence of flying materials, it is necessary to control the ultrafine powder in each raw material in the batch. The ultrafine powder in the batch material mainly comes from silica sand, quartz sand, limestone, etc. As long as the purchase of raw materials is carried out in strict accordance with the standards, in the preparation process of the batch materials, the content of the superfine powder of the batch materials can be reduced, the generation of flying materials can be reduced, and the service life of the furnace can be improved.
