Introducing the new Sialon alternative for graphite rotor impeller & 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.
A 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, impellers 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.