Graphite rotor

Graphite rotor is mainly used for purification of aluminum liquid. The liquid aluminum alloy purification process is the main means to improve the overall performance of aluminum alloy. During the purification process, the purification method of mixing the purification gas with the solvent and blowing the aluminum melt using the rotation of the graphite rotor is currently an internationally advanced treatment method.
Working principle of graphite rotor for degassing aluminum liquid: The graphite rotor consists of two parts: the rotor rod and the nozzle. The transmission system drives the graphite rotor to rotate, and argon or nitrogen is blown into the aluminum melt through the rotor rod and nozzle. The high-speed rotating graphite rotor breaks up the argon or nitrogen gas that enters the aluminum melt, forming many small bubbles that are dispersed in the molten metal. At the same time, the rotating rotor also promotes the diffusion of hydrogen and inclusions in the aluminum melt, causing them to interact with the aluminum melt. Bubble contact, the bubbles in the melt rely on the principle of gas partial pressure difference and surface adsorption to absorb hydrogen in the melt, adsorb and oxidize slag inclusions, and are taken out of the melt surface as the bubbles rise, so that the melt can be purified.
Anti-oxidation graphite rotor is made of high-purity graphite. The quality of the graphite itself has a significant impact on the service life of the rotor. At the same time, the surface is coated with an antioxidant protective coating, which can extend the service life to 50-60 days.
Use and maintenance of graphite rotor:
1. The rotating nozzle is made of high-purity graphite. In addition to breaking bubbles, the structure of the nozzle also uses the centrifugal force generated by stirring the aluminum alloy melt to make the melt enter the nozzle and mix evenly with the horizontally injected gas to form gas. /Jet liquid flow to increase the contact area and contact time between bubbles and aluminum alloy liquid, and improve the degassing and purification effect.
2. The high-temperature resistant and anti-oxidation graphite rotor treated by a special process is 3-4 times more durable than non-oxidation-resistant rotors. It can be stored at around 700℃ for 55-65 days, and above 1000℃ for 25-35 days. There is an anti-oxidation protective coating on the surface, which can extend the service life to 50-60 days.
3. Before the aluminum casting graphite rotor is immersed in the aluminum liquid, it should be preheated at about 100mm above the liquid level for 5 to 10 minutes to avoid the impact of rapid cooling on the material; gas must be introduced before the rotor is immersed in the liquid; the rotor should be lifted out of the liquid before the gas supply is stopped. surface to avoid clogging the air holes of the rotor nozzle.
    4. The main cause of graphite rotor damage is high-temperature oxidation: the main component of graphite is carbon. Graphite undergoes significant oxidation in air conditions above 600°C. The products of the carbon oxidation reaction are CO and CO2 gases, which cannot protect the rotor. Function: Generally speaking, the degassing box cannot be completely sealed, and most of the inner chambers of the box are not filled with protective gas for protection, so oxidation of the graphite rotor is inevitable. Due to oxidation, the diameter of the rotor shaft gradually becomes smaller until it breaks and is scrapped.