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Application Of Phosphate Combined With High Alumina Refractory Castable In Aluminum Melting Furnace
Dec 18, 2018

In recent years, aluminum alloy products have become the most widely used non-ferrous metal materials. Therefore, melting furnaces and holding furnaces for aluminum alloy smelting are also increasing. In the melting process of aluminum alloys, aluminum liquid, molten slag and air are prolonged for a long time. Corrosion, the refractory castables used are damaged frequently, which seriously affects the production needs of enterprises. Therefore, it is urgent to seek refractory castables with high resistance to erosion and good performance.


Aluminum melting furnace


Phosphate combined with high alumina refractory castables with high density and high wear resistance. Compared with traditional high alumina refractory castables, it has the following main features:


1. This high-aluminum refractory castable is combined with phosphate liquid to produce strength through chemical coagulation reaction, which has the advantages of fast hardening and high early strength. The strength of room temperature × 3h is much higher than the traditional high aluminum castable and low cement castable.


2. The castable binder is liquid phosphate. No water is added during the construction process to avoid the performance deviation caused by the amount of water added. When packaging, the matrix material is packaged separately from the bonding agent, and the ratio is more precise during the construction process.


3. The castable has strong anti-corrosion performance to molten iron and aluminum alloy solution.


4. The castable can be well combined with refractory materials of other materials to meet the needs of emergency quick repair of the kiln.


5. Since no water is added during the construction process, rapid heating and rapid drying can be achieved in the process of the oven. A series of problems caused by improper baking of refractory castables like traditional cement are avoided. This is more effective for irregularly shaped and thicker construction bodies.


Phosphate high alumina castable


Construction of phosphate combined with high alumina refractory castable


The combination of phosphate-bonded high-aluminum castables and traditional castables is very different. The following points should be noted in the construction work:


1, the model


The die is a necessary part of the construction of refractory castable. When the phosphate is combined with the high alumina castable, the metal formwork and the wooden formwork can be used. The metal formwork has good effect, but the cost is high. When using a wooden formwork, it is necessary to apply the lubricant evenly before installation, wipe off the excess part, and prevent the lubricant from falling on the surface of the hearth, thus affecting the combination of the castable and the furnace body.


2, stirring


Phosphate combined with high aluminum castables hardens quickly, so the mixing time is very short. From mixing to pouring construction, it usually takes 2 minutes. If it is more than 2 minutes, it may affect the construction quality. After the mixing operation is finished, the castable on the mixer should be cleaned and finally washed with water.


It should be noted that: 1) the material cannot be stopped once it starts to stir. 2) The material cannot see water during the mixing process, otherwise it may burst during the post-baking process.


3, pouring


1) Since the castable after agitation is very viscous, the fluidity is poor, and hardening starts in a very short time. Therefore, the mixture should be poured into the mold immediately after the mixture is evenly mixed, and the shaker is used to level the first time after pouring. If the amount of construction is large, the vibrator should be used continuously, and if necessary, use two wheels instead. Note that the insertion depth of the vibrator should not exceed 60 mm to prevent voids due to hardening of the material and affect the construction quality.


2) After the castable material is hardened, it will bulge upward beyond the height of the designed construction body due to expansion. Therefore, the surface finish should be performed before the construction body is cured.


3) After the completion of the construction, the construction body rapidly heats up due to chemical changes between the materials, and the strength increases sharply. If the temperature rises quickly, the mold can be hardened by 30 to 60 minutes. If the temperature rises slowly, the mold can be removed in 3 hours. It should be noted that the longer the hardening time, the more difficult it is to remove the mold, so it is necessary to demolish the mold as soon as possible according to the temperature rise.


 


Effect of phosphate combined with high alumina refractory castable


The use of phosphate combined with high alumina refractory castables not only effectively extends the service life of the aluminum melting furnace and the holding furnace lining, but also reduces the number of repairs. The practical application proves that after 5 months of use in the aluminum melting furnace, the wall hanging slag is not obvious, and the trace of aluminum slag erosion is hardly seen.


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