The principle of the online Metal Degassing Unit is to allow the molten aluminum to fully contact the inert gas in a purification room, so that the hydrogen present in the molten aluminum diffuses into the inert bubbles with zero hydrogen partial pressure and escapes liquid level. The solid inclusions suspended in the aluminum liquid will also be adsorbed on the surface of the bubbles and be removed together.
After online purification treatment for molten aluminum, the hydrogen content of molten aluminum can be reduced to half of the original value. Non-metallic inclusions with a particle diameter below 50μm can be removed by 50%, and those above 100pm can be removed by 90%. Adding Cl2 in the inert gas can increase the hydrogen removal rate from 50% to 65%, and also remove 60%-75% of Na and Li. This is useful for the production of aluminum-magnesium alloys and the direct extraction of molten aluminum from the electrolytic cell to produce aluminum Material is very important.
The inert gas can be dispersed into tiny bubbles into the aluminum liquid through the rotating nozzle. The emotional gas can be nitrogen or argon. Nitrogen must be high-purity nitrogen with a purity greater than 99.995%. The cost of argon is higher than that of nitrogen, but its advantage is that it will not react with molten aluminum to form compounds at high temperatures. After the aluminum liquid is purified online, the hydrogen content should be below 0.12mL/100g(Al). For products with strict quality requirements, the hydrogen content should be below 0.10m/100g(Al).
The time for the molten aluminum to pass through the Metal Degassing Unit is very short. After processing, it is difficult to completely separate the smaller slag and inclusions from the molten aluminum in such a short time. In order to ensure the cleanliness of molten aluminum, all purification devices outside the furnace are equipped with filtering devices to remove suspended debris.