Experiment Research Of Electromagnetic Purification Of Molten Aluminum Alloy With High Frequency Magnetic Field

Electromagnetic Purification (EMP), which is a new technique of purification, has become one of research focuses because of its non-pollution, high-efficiency and less effect of the different density between the melt and nonmetallic inclusions. So AC magnetic field purification, which is one of the electromagnetic purification, has also become one of the main study hots because of its convenient application.In this paper, electromagnetic body force has been deduced on the base of the Maxwell equations and the model of EMP which can calculate purification time and efficiency of different diameter inclusions in molten metal has also been set up.In order to accurately analyze the effect of high frequency electromagnetic field on the non-metallic inclusions, the EMP experiments have been done with the 100 μm , 30 μm and 10 pm primary silicons which are used to simulate the nonmetallic inclusions and are produced by 18%(with phosphor and without phosphor), 12.6% and 10% Al-Si alloys respectively. The results show that the primary silicons are more suitable to simulate the non-metallic inclusions in molten aluminium. When the magnetic induction intensity is 0.03T, the non-metallic inclusions with the diameter 100 μm can be eliminated in 10 seconds. And the single non-metallic inclusions with the diameter 10 μm can also be eliminated by electromagnetic repulsive force.The key problem in EMP is how to eliminate minor diameter non-metallic inclusions. So alumina particles with diameter 5 μm have been added into molten aluminum at certain position.The following experiments are done:1. In order to verify the flow in molten aluminum with Electromagnetic body force, alumina particles have been added into melt at certain position with 0.7mm diameter iron core which is wrapped by aluminum foil;2. In order to simulate EMP in hollow pipe, alumina particles have been added into melt with 2mm diameter iron which is wrapped by aluminum foil;3. With alumina particles in the melt, EMP has been performed without iron core in tubule. The results show that when the magnetic induction intensity is more than 0.03T, the flow in themolten aluminum will strongly affect on elimination of minor diameter non-metallic inclusions. And even if the experiment is done in hollow pipe and the purification time is 120 seconds, thealumina particles with diameter 5 μm cannot be completely eliminated when the magnetic induction intensity is 0.06T.