Aluminum Degassing Methods used in the aluminum foundry mainly include the Air Liquide method, Snif method, Alpur method, in line degassing system, online degassing system.
Aluminum Degassing Methods
Air Liquide method is a primary form of continuous performance treatment outside the furnace. The bottom of the device is equipped with a permeable brick. The nitrogen gas forms a tiny bubble through the permeable brick and rises in the melt. The bubble absorbs gas and impurities in the process of contact and movement with the melt, and brings out the surface to produce purification effect. Although this method can remove slag, the effect is not ideal
Snif method: the abbreviation of rotating nozzle inert gas floating method is an external treatment device for aluminum melt developed by United carbide company. There is no filtering device in this method. There are two graphite gas rotating nozzles in the two chambers. The gas is opened into dispersed fine bubbles through the rotor of the nozzle. At the same time, with the melt stirred by the rotor, the bubbles are evenly dispersed into the whole melt, so as to produce the purification effect. This method avoids the aggregation of bubbles caused by blowing gas in a single direction, and the continuous gas channel formed by floating upward shortens the contact time between gas and melt, thus affecting the purification effect. The blowing gas is nitrogen and argon. In order to improve the purification effect, 2% ~ 5% chlorine can be mixed.
Alpur method: developed by bischner company in France. In addition, the rotating nozzle is used to spray the refined gas into the melt in the form of micro bubbles. But different from the snif nozzle, it stirs the melt into the nozzle at the same time to contact with bubbles, which improves the purification effect. The gases are nitrogen and argon
The melt in line degassing system is a kind of melt furnace invented by cona1co in 1982. The aluminum melt enters the cylindrical reaction chamber in a tangent way from the inlet of the, which makes the melt rotate. The lower part of the reactor is equipped with gas nozzles, dispersing small bubbles and dispersing bubbles into the whole reactor by rotating melt, resulting in better purification effect. After the melt flows out of the reaction chamber, it enters the ceramic foam filter and can enter non-metallic inclusions. The gas used for purification is argon, and a small amount of chlorine can also be added.
AdTech Online degassing system adopts advanced high silicon melting technology to get a long service time, degassing rotor, heater protection thimble, and thermocouple protection thimble to adopt ceramic manufacturing technology that can meet producing high-precision aluminum requirements. Online degassing unit shall be installed between the furnace and casting equipment. It is used for hydrogen (H) and slag removal from molten aluminum. The online degassing unit has dual functions: processing and heating. It serves high precision molten aluminum purification industry.