In the field of steelmaking and refining, phosphorus is impurities. The steel is produced by removing reacted with slug to it. Improving the reaction speed of phosphorus contribute significantly to the reduction of steel making process and it can achievement by increase interfacial area between slug and metal. So the purpose of this research is to increase interfacial area efficiently by electromagnetic force (EMF) instead of inert gas. It revealed that it is possible to sloshing of the liquid metal by electromagnetic force in horizontal directions by numerical simulation and increasing the interfacial area during sloshing. Performs approximate analysis by linear theory for horizontal sloshing of the multiliquid-layer and compered with the numerical value. In addition, new vertical sloshing method that is locally applied electric field and magnetic field is devised.