Cause analysis of aluminum melt bubbling， porous ceramic filter
Melt churning and bubbling will occur during the smelting, purification, and casting process of aluminum alloy. This phenomenon is mainly due to the volume expansion of the water vapor released from the contact part of the aluminum melt when heated. The source of water vapor is mainly from the following conveniences:
1. The crystallization water inside the refractory material in contact with the aluminum melt is not completely discharged
For refractory materials such as smelting furnace lining, porous ceramic filters, purification equipment lining, degassing unit, launder lining, etc. that are directly in contact with the aluminum melt, after the masonry or molding is completed, the baking temperature curve is set unreasonably, and the baking time at the medium and low-temperature stage is short, the internal water of crystallization is not completely removed; during use, the remaining internal crystallization water is heated and discharged again, and after entering the aluminum melt, the temperature rises and the volume expands rapidly, causing the aluminum liquid to churn and bubble. This phenomenon is generally easy to appears when the equipment is put into use. With the prolongation of the use time, the churning and bubbling of the aluminum melt will gradually decrease or disappear.
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2. The refractory material in contact with the aluminum melt is damp to produce adsorbed water
Some equipment has a low frequency of use and long intervals of use. When the equipment is idle, it absorbs water vapor in the air to form adsorbed water. The baking preheating is insufficient, and the internal adsorbed water is not completely removed. When the aluminum melt contacts the refractory material, the temperature rises, the water vaporizes and discharges the refractory material into the aluminum melt, and the rapid volume expansion causes the aluminum melt to churn and bubble. This phenomenon generally occurs at the beginning of each casting and does not occur at the end of use or continuous use.
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3. Water leakage in the contact place between the refractory material and the water-cooling equipment
This phenomenon mainly occurs in the refractory part. The contact part between the refractory material of the refractory plate and the crystallizer water tank is not tightly sealed, and the water in the water tank leaks into the refractory material. When the temperature rises, the water vaporizes and the refractory material is discharged into the aluminum melt. The rapid volume expansion causes the aluminum melt to churn and bubble. This phenomenon generally occurs in the entire cycle of the casting process, even every casting.
porous ceramic filter
