Aluminum degassing system adopts a dual-rotor gas refining device, which refining gas is blown through the rotating nozzle to generate tiny bubbles. The rotating nozzle is made of graphite. The nozzle structure design takes into account the uniform ejection of bubbles. The rotating impeller is also used to break the bubbles, increase the contact area and contact time between the bubbles and the aluminum melt, and improve the effect of purifying the aluminum melt.
Due to the high viscosity of aluminum alloy melt, if the diameter of the vent hole is too large, it is easy to stick aluminum and block the pores. According to the gas flow rate and the pressure of the molten metal in the cylinder, it is calculated that the diameter of the rotor pores is 2mm to ensure the purification treatment effect. The degassing unit itself has two heaters, which are used to preheat the container before injecting the aluminum melt, and can maintain or increase the melting degree according to the characteristics of the cast alloy.
On-line aluminum degassing system mainly ensures that the three requirements of degassing, alkali metal removal, and slag removal are met during the casting of molten aluminum to ensure the purity of molten aluminum.
The hydrogen is removed by dissolving and adsorbing hydrogen into the bubbles. The high-speed rotating nozzle breaks the large and fast-floating large bubbles into countless small bubbles, increasing the surface area of the refined gas more than ten times or even dozens of times. These small refining bubbles are evenly dispersed in the molten aluminum and float slowly.
Alkaline metal reacts with chlorine to produce chlorine salt to remove the alkaline metal slag trapped by the bubbles, and the larger slag inclusion and bubble collision are trapped.
Smaller slag inclusions are captured by the radial cross-section of the bubbles, and then the slag inclusions rise to the surface with the bubbles to form scum, thereby obtaining a better purification and refining effect of molten aluminum.