The diamagnetic mode of OGMS

Open gradient magnetic separation (OGMS) has so far been carried out in the so-called paramagnetic mode. In order to improve magnetic separation efficiency it is necessary to utilize the negative mass susceptibility of diamagnetic particles in an arrangement which will facilitate their deflection away from the paramagnetic stream. This can be done by moving the launching point from the edge of the separation zone into a region of high magnetic energy density close to the separator wall and by inclining the separator. The separation process then relies more on repelling the diamagnetic species than attracting the paramagnetic ones. Hence the name diamagnetic for such a mode of separation. The newly discovered diamagnetic mode of open gradient magnetic separation (OGMS) is described in detail both theoretically and experimentally. Excellent agreement between the theory and experiment is found and the new method is applied to a pilot plant beneficiation of trona.