There are many factors that affect the life of aluminum alloy melting furnace lining, mainly including refractory quality, furnace construction quality, furnace loading and cleaning operations, aluminum liquid erosion of refractory materials, alkali metals and alkaline earth metals Na, K, Mg in aluminum liquid erosion of refractory materials, and refractory wear. According to the damage factors of aluminum alloy melting furnaces, there are mainly the following effective measures to prolong the refractory lining for aluminum alloy melting furnaces:
01 Correct selection of furnace refractory materials is very important for prolonging the life of melting furnace/insulating furnace lining. It is necessary to select refractory materials with high Al2O3 content and those that do not produce free SO2 during use, and the content of impurities such as Fe2O3, TiO2, NaO, K2O, etc. in the materials should be as low as possible to minimize the reduction of Fe2O3, TiO2 and SiO2 by aluminum during aluminum alloy smelting and the formation of expanded phases of potassium nepheline and nepheline; it is necessary to select refractory materials with low cement content in the furnace lining to reduce the linear shrinkage of the refractory lining during operation, improve the thermal shock resistance of the furnace lining material, and avoid cracks in the furnace lining material due to thermal shock and aluminum leakage.
02 Construction process During the masonry of the smelting/insulating furnace, the construction process used must be appropriate. It is necessary to strictly control technical parameters such as brick joints, mortar saturation, water addition amount of castables, stirring time, etc. to avoid excessive brick joints due to improper furnace construction technology, resulting in aluminum liquid leakage in the brick joints during furnace operation, which affects the service life of the furnace lining.
03 Furnace baking process The correctness of the furnace baking process is crucial to the service life of the refractory material. During the furnace baking process, it is necessary to control the initial preheating time and heating speed of the furnace, set the necessary insulation time, so that the heat has enough time to diffuse into the furnace lining, maintain the uniformity of the furnace lining temperature, reduce the temperature gradient in the furnace lining and the stress generated by the temperature gradient to the minimum, and prevent the furnace lining from cracking due to stress concentration.
04 Furnace building process Due to the problems of many brick joints, poor integrity and poor strength in the traditional brick masonry furnace process, it is easy to cause rapid cooling and heating caused by frequent opening and closing of the furnace door (furnace cover) and collisions during operation during use, causing some parts of the furnace to be easily damaged. High-strength and low-cement content castables are used in the key parts of the smelting furnace, and the integral casting one-time molding process is used for the furnace lining masonry casting, so that the strength of the key parts of the furnace lining is improved and improved, which can greatly increase the overall service life of the smelting/insulating furnace.
05Operation process Carefully and conscientiously operate the melting/holding furnace. Whether it is manual charging or charging by a charging car, try to avoid the collision and impact of solid charge or charging machinery on the refractory materials at the bottom and wall of the furnace when loading the furnace.
06Change the traditional furnace cleaning method and change the currently commonly used manual cold furnace cleaning to hot furnace cleaning by a furnace cleaning car. Because in the cold state, the various impurities, slag and corundum nodules adhering to the bottom and wall of the furnace are particularly tightly combined with the refractory lining. If they are forcibly cleaned, they will inevitably cause serious damage to the refractory lining. In the hot state, due to the high ambient temperature in the furnace, the impurities, slag and corundum nodules adhering to the bottom and wall of the furnace have great elasticity and plasticity. At this time, cleaning can utilize their hot deformability to greatly reduce the damage to the lining refractory materials.
07The service life of the refractory materials of the aluminum melting furnace is very important for producing high-quality aluminum alloy casting products at a lower unit cost. The factors that affect the service life of refractory linings are very complex. Furnace building materials, masonry technology, furnace baking system, alloy types, daily operations, furnace cleaning methods, and daily maintenance all have an important impact on the service life of refractory linings. Therefore, extending the service life of refractory linings of melting/holding furnaces is a comprehensive project.
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