I. Introduction
High Gradient Magnetic Separation (HGMS) is an efficient way to recover weakly magnetic minerals. Since the 1970s, HGMS separators have been implemented to the recovery of the magnetic ore such as hematite, siderite limonite and rare earth minerals, and purification of non-metallic ore like quartz, feldspar, fluorite and kaolin [1]. In order to prevent matrix clogging and improve beneficiation efficiency, Vertical-ring High Gradient Magnetic Separators (VHGMS) with pulsating mechanism were invented and successfully applied to treat weakly magnetic minerals [2].