Magnetic force on a magnetic particle within a high gradient magnetic separator

► Magnetic field and the gradient decide magnetic force on a particle in HGMS (High Gradient Magnetic Separation). ► We calculated the field and the gradient of a superconducting HGMS system by finite element method. ► We could calculate magnetic force on a particle consisting of major impurities in the condenser water of a thermal power station. HGMS (High Gradient Magnetic Separator) uses matrix to make high magnetic field gradient so that ferro- or para-magnetic particles can be attracted to them by high magnetic force. The magnetic force generated by the field gradient is several thousand times larger than that by background magnetic field alone. So the HGMS shows excellent performance compared with other magnetic separators. These matrixes are usually composed of stainless steel wires having high magnetization characteristics. This paper deals with superconducting HGMS which is aimed for purifying waste water by using stainless steel matrix. Background magnetic field up to 6T is generated by a superconducting solenoid and the stainless steel matrixes are arranged inside of the solenoid. Based on magnetic field calculated by FEM (Finite Element Method), we could calculate magnetic force acting on a magnetic particle such as hematite and maghemite consisting of major impurities in the condenser water of a thermal power station.