Sialon Rotor and Shaft is a best alternative for graphite rotor and shaft for degassing in molten aluminium. Sialon degassing rotor is composed of a sialon shaft and sialon rotor with quick or threaded coupling and by the rotor impeller. The degassing rotor geometry is designed for adapting to degassing devices used in furnaces and ladles. The sialon rotor can be used in a wide temperature range: from 650 to 1400° C. The sialon has excellent non-wetting properties and a very long service life compared to graphite rotors and shafts.
The Sialon rotor shaft impeller is designed to inject and evenly disperse an ascending flow of tiny bubbles of the process gas (inert gas, with a possible addition of chlorine to reduce alkali). Now, we introduce the new Sialon alternative for graphite degassing rotor and shaft to be used for degassing in molten auminium. Graphite rotors, impellers and shafts are widely used for dispersing hydrogen of Aluminium.
During aluminum and aluminum alloy smelting, hydrogen produced by chemical action with steam diffuse in molten aluminum, which will cause inner structural defect to aluminum products.
In order to avoid such defect, most aluminum factories apply dissolved gas floating method to purify molten aluminum. i.e. inert gases such as nitrogen, argon is injected into molten aluminum, and hydrogen will be brought to molten aluminum. surface with spread and rise of inert gas.
Sialon Rotor and shaft set is necessary to inject inert gas and stir for degassing regarding both intermittent and continuous online degassing methods. Because of its unique properties of heat-resistance, anti-oxidation, high strength and non- infiltration, Sialon becomes the optimal choice for material of rotor and shaft, which is known as graphite rotor/impeller and shaft set.
Nowadays, as an alternative to graphite rotors and shafts, ultrasonic degassing in molten aluminium has now become the standard. A 20 kHz ultrasonic generator creates cavitation which disperses the hydrogen in the aluminium bath. This technology is also used for ultrasonic grain refinement and ultrasonic micro-alloying in molten non-ferrous melts.
