Study On Electromagnetic Purification Of Iron-rich Phase From Aluminum Melt

As a new technique of purification, electromagnetic purification (EMP) 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. High frequency alternating magnetic field was used in the experiment, It mainly makes use of the different conductivity between the iron-rich phase and melt, and can remove micron-grade iron-rich phase from metal melt by the extrusion force of electromagnetic field, hence realize the aim of melt purification.In this paper, electromagnetic body force has been deduced based on the Maxwell equation. And a calculation model which can calculate the migrated velocity of the solid grain in the molten metal has been set up. Further more, the influencing factor on the electromagnetic separation efficiency has been analyzed, including the magnetic field intensity, tube diameter, acting time and so on. Al-2%Fe alloys were used in the experiment performing to investigate the migrating behavior of the primary iron-rich phase in the quiescent melt. By adding Mn into melt to change the shape of iron-rich phase, the effect of the shape of iron-rich phase on electromagnetic purification efficiency was investigated, Al-5%Fe particle reinforced composite material was produced by electromagnetic purification process under high frequency magnetic field.The microstructure and component of the alloys were analyzed, the optimal parameters were optimized, when the tube diameter is 10mm, magnetic field intensity is 0.04T, and acting time is 30s, a very good separation effect can reach. The shape of iron-rich phase can be altered by adding the Mn, when Mn/Fe molar ratio is 1.3～1.5, the long need-like iron-rich phase was changed into piece or sphere, which was easy to migrate in the aluminum melt. Electromagnetic filtration with manganese can remove iron-rich phase better, drop the Fe content, and make separation efficiency enhanced, so that the elongation was enhanced further, from 4.0% to 29.2%. At last, Al-5%Fe particle reinforced composite material was fabricated, whose surface layer is rich in Fe(8%～8.5%) with hardness up to 80HV, and a transitional layer existed between the center area and the surface layer, making the reinforced phase and matrix jointed firmly.