The current aluminum melt processing technology has been developed from a single degassing or filtration in the past to a continuous treatment technology combining degassing and filtration. In order to improve the quality of aluminum materials, aluminum foundries use the two functions of degassing and filtering to process molten aluminum simultaneously.
Non-metallic inclusions and gas (mainly H) in the melt are the key factors that affect the casting process and the quality of the ingot. Aluminum alloy has a serious tendency to oxidize and get gas. In the smelting process, it is in direct contact with the furnace gas or the outside atmosphere. During the smelting and aluminum liquid transfer, gas and inclusions will be generated in the melt due to gas absorption and oxidation. The cleanliness of molten aluminum is reduced, and inclusions and gases in the metal have a significant impact on the strength, fatigue resistance, corrosion resistance, and stress corrosion cracking performance of aluminum alloy profiles. Effectively controlling the oxidized inclusions in the melt and improving the internal quality of cast rods and slabs have become the common goal pursued by metallurgy, casting, and material processing.
The aluminum melt processing purification is mainly degassing and slag removal, so a series of advanced purification technologies such as online degassing and ceramic filter filtration is used to purify molten aluminum. Online degassing and filtration treatment can ensure the quality of molten aluminum and avoid product complaints and disputes caused by insufficient purity of downstream processing customers.
The aluminum alloy purification adopts the international advanced degassing filter system. The online degassing system adopts dual-rotor gas refining device technology. The dual-rotor gas refining device has high efficiency in removing gases, inclusions and certain harmful elements in the aluminum melt, and can achieve a satisfactory hydrogen removal effect, ensure the internal quality of the ingot.
Filtration is the most effective and reliable method to remove non-metallic inclusions in aluminum alloy melt. Melt filtration includes mesh filtration, foam ceramic plate filtration, and microporous ceramic tube filtration. Currently, foam ceramic plate filtration is widely used. The CFF filtration system adopts single-layer and two-stage filtration according to the throughput of molten aluminum per unit quantity of the casting platform, and meets the filtration requirements of high-end customers according to the requirements of customers in production.
