Experimental Research On Electromagnetic Separation Of Metal Droplets From Liquid Steel Slag

As by-product of steel production,the annual output of steel slag is quite huge.Steel slag typically contains waste iron and steel about 8-15%.Traditional steel mills recycle the waste iron and steel in the steel slag by crushing,magnetic separation,screening process,the processing technology is complex,the investment in equipment is large,the metal recovery rate is low,and the environment pollution is heavy.Aim at the physical property differences of slag and steel(specific gravity,electrical conductivity,viscosity,inter facial tension),a new separation method which is completely different from the traditional way between slag and steel separated by a electromagnetic field will be proposed in this proposal.Numerical and experimental studies were performed on the effects and laws of separation of slag and steel in molten steel slag by using the modulated helical magnetic field.1.The experimental measurements were performed to study the magnetic field intensity distribution of its internal space of modulated helical magnetic field device.The results show that the magnetic field strength is generally characterized by strong at both ends and weak center,but the attenuation at the center is small.The driving effect of the liquid GaInSn(liquid at room temperature)were measured under the mode of electromagnetic field.The results show that the metal liquid can be driven obviously bi the device and different driving effects in the forward and reverse directions of the metal liquid can be achieved.2.In the high-temperature thermal experiment,whether the modulated helical magnetic field was applied or not,and under the effect of the mode spiral magnetic field,the effects on the separation of slag and steel of the magnetic field strength and the acting time were studied.The experimental results show that the separation effect of slag and steel can be improved significantly through applying electromagnetic field and the separation effect is best when the modulated helical magnetic field strength is about 40mT;Different electromagnetic field action time also had a certain influence on the separation effect of slag and steel.The separation effect is best when the action time is 80 s.3.In order to understand the process of metal droplets coalescence and separation better,the Ga InSn alloy and Glycerol were used to simulate high-temperature thermal experiment at room temperature to observe the aggregation,coalescence and separation of metal droplets.The result shows that the application of electromagnetic fields can promote metal droplets to merge.But the repeatability of the experimental results can't be guaranteed under the same conditions.4.A numerical model was established with a commercial software COMSOL to simulate the distribution of magnetic field and the electromagnetic force effected on the metal droplets in the two-phase system of liquid slag and liquid steel under the condition of the modulated helical magnetic field.The simulation results show that when the rotating magnetic field rotates at 150 rpm,the magnetic induction intensity on a metal droplet with a diameter of 5mm is about 250 mT,and the metal droplets can be deformed and finally merged.This study shows that based on the physical properties differences of slag and steel by using electromagnetic separation methods and the Lorentz force,to move the liquid metal and achieve the purpose of electromagnetic separation is feasible.Further quantitative analysis should be carried out in order to apply these techology to practical production.