Rotary Degassing for Aluminum Alloy Melt Purification

Rotary degassing purification method is a kind of bubble floatation method, and it is also the most widely used aluminum alloy melt purification method. Rotary blowing degassing purification method by degassing unit is to pass inert gas in aluminum alloy melt in the aluminum alloy melt. It is broken and ejected at high speed when flowing through the rotating nozzle blades at the lower part, resulting in a large amount of foreign air bubbles.

Rotary Degassing

Since the partial pressure of hydrogen in the bubble is zero, the hydrogen dissolved in the aluminum alloy melt continues to enter the bubble according to the principle of hydrogen removal kinetics until the partial pressure of hydrogen in the bubble increases to meet the concentration of hydrogen in the aluminum alloy melt. Balance is reached when a certain relationship is reached. After the surface of the bubbles, the hydrogen in the bubbles enters the atmosphere. At the same time, the bubbles also have the function of adsorbing the oxidation inclusions in the aluminum alloy melt, and also take away the hydrogen adsorbed on the oxidation inclusions.

In the process of rotating spraying and degassing to purify the aluminum alloy melt, the rotating nozzle rotates at a high speed. During the rotation of the nozzle, the fluid sprayed by the nozzle blades produces strong turbulence. The bubbles ejected from the high-speed rotating nozzle are quickly captured by the liquid ejected by the nozzle blades and the relatively slow liquid around the nozzle near the nozzle. The bubbles are affected by the turbulent shear stress generated by the two layers of fluid. When the bubble can withstand, it is cut from it and split into two bubbles.

The split bubbles are captured by other tangent liquid layers, and they can continue to split into smaller bubbles until the shear stress between the two fluids is not enough to break the bubbles or the bubbles get out of the scope of the shear stress. This can produce bubbles that are smaller and more uniform than single or multi-tubes, effectively increase the specific surface area, and effectively increase the mass transfer and diffusion capacity, and at the same time extend the contact time of the gas-liquid interface. , Make the purification bubbles escape, so that you can get an excellent purification effect.

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