Degassing and refining non-ferrous melts with rotating rotor
One of the technologies widely used in the world, along with fluxes, is the technology of degassing molten aluminum and its alloys by processing the melt with rotating rotor with inert gas purging.
1. Operation principle:
A special rotor is immersed in the aluminum melt which starts to rotate at a speed of 350 – 600 rpm, and an inert gas (most often nitrogen) is purged through it. The processing time is from several minutes to 10 minutes. The special shaped rotor with channels ensures uniform distribution of inert gas bubbles in the melt. The rotor material based on SiC/C is specially designed for long-term operation in the aluminum melt. On average, the inert gas consumption (if nitrogen) is 20 liters of nitrogen per minute for every 100 kg of the aluminum melt. So, to process 1,000 kg of the aluminum melt, you should process for 10 minutes at a flow rate of 20 liters of nitrogen per minute.
2. This technology enables the following:
·Degassing effectively by hydrogen removal from the aluminum melt. The lowest possible hydrogen level is achieved using this technology. The operation principle is based on hydrogen diffusion from the melt into inert gas bubbles;
·To remove some non-metallic inclusions due to the bubbling effect.
3. It has the following advantages compared with treatment with flux:
· higher degree of degassing (hydrogen removal) from the aluminum melt;
· low operating costs;
· environmental compliance;
· degassing in furnaces during continuous casting of metal.
4. Rotor service life:
It depends on the alloy, melt temperature, grade of fluxes used, rotor speed and processing time. The average operating life according to some plant data is the following:
- Shaft furnace with a capacity of 2,000 kg: the service life was 20 weeks with a processing time of 4 minutes, processing was with the refining flux;
- Induction furnace with a capacity of 350 kg: 588 operating cycles with a processing time of 10 minutes.
- Bath furnace: more than 2.000 operating cycles with a processing time of 2-10 minutes.
Rotor before (left) and after (right) long operation
Distribution of bubbles of inert gas during operation of the rotor
Some standard rotor sizes
Length of the rotor together with the holder
|up 600 to 1200 mm|
|150 mm||150 mm|
|75 mm||94 mm|
5. We offer both a complete set of melt processing equipment in this way, as well as spare parts - special rotors from Morgan Molten Metal Systems