The hydrogen content and non-metallic inclusions in aluminum and aluminum alloy melts have an important impact on the quality of secondary aluminum. Aluminum and aluminum alloy melt purification technology can improve the quality of secondary aluminum. Therefore, the aluminum and aluminum alloy melts must be purified.
In the past, the commonly used method for purifying aluminum and aluminum alloy melts was to use inert gas to refine the melt in batches in the holding furnace, and to filter the melt with glass cloth during the transfer process. Generally speaking, the purification effect of furnace melt purification treatment on aluminum and aluminum alloy melts is quite limited.
With the continuous improvement of the quality requirements for secondary aluminum, this type of aluminum and aluminum alloy melt processing methods can no longer meet the requirements. As a result, the MINT method (melt in-line treatment system), SNIF spinning nozzle inner flotation, Alpur rotary degassing method, LARS rotary degassing method, DBF deep bed filtration method, ceramics On-line purification technology of aluminum and aluminum alloy melt such as ceramic tube filtration and CFF ceramic foam filtration.
The successful application of online purification technology in the secondary aluminum industry provides a reliable guarantee for reducing the hydrogen content in aluminum and aluminum alloy melts, removing non-metallic inclusions, and improving the purity of aluminum and aluminum alloy melts and the quality of secondary aluminum.
The filtration after the hydrogen removal treatment is the most effective and reliable means to remove non-metallic inclusions in the aluminum melt. There are many ways to filter, the most effective ones are corundum filter tube and foam ceramic filter plate. Corundum tube filter has high filtration efficiency, but it is more expensive and inconvenient to use. The foam ceramic filter plate is convenient to use, good in filtering effect, and low in price. It is widely used all over the world.
At present, aluminum alloy melts are filtered by foam ceramic filter plates. At present, the technology of box-type foam ceramic filter plate is generally used. It is a filter box with a gas preheating cover system. When the molten aluminum passes through the filter plate, the inclusions in the melt are mechanically blocked by the filter to achieve the purpose of eliminating separation. This method has a good filtering effect.