Development Of High-gradient Permanent Magnetic Separator With Inclined Cylinder And Its Application

High gradient magnetic separation originated from the US in the last 1960s, which inaugurated a new way to separate the low-grade, fine grain size and weakly magnetic ore. With the development of high gradient magnetic separation theory and equipment, it has broken the traditional application, and enters the fields of medical science and biology, etc.The separation cylinder of high gradient magnetic separator (HGMS) has two basic configurations, that is, horizontal configuration and vertical configuration. The gravity of particles in the separation process is competitive force in this type of HGMS. With the development of rare earth permanent magnet materials and the necessity of energy conservation, magnetic separation equipment tends to applying permanent magnet. This paper developed a high gradient permanent magnetic separator with inclined cylinder (HGPMSIC); the main features of the machine are as follows:①The separation cylinder is inclined configuration, the inclined angle can be adjusted between 0～90°, and rotational speed is the range of 0-20r/min. These features can change the hydrodynamics of plup and the effect of gravity, to some degree, gravity acts as a separation force in the beneficiation process.②The magnetic system of HGPMSIC was a semi-closed magnetic circuit permanent magnetic system, and magnetic covering angle was 125°. The iron yoke fixed the magnets and convey magnetism to reduce flux leakage, so that magnetic lines concentrated in the separation area.③The cylinder of HGPMSIC drived by a gear variable speed motor and a rigid flange coupling, and the adjustment of inclined angle is achieved through the Electromotive handspike.During the separation process of HGPMSIC, there were many forces acting on the micro-fine mineral particle, including magnetic force, fluid force, gravity, the interaction between particles (electrostatic force and van der Waals force), etc.The magnetic force and component of gravity perpendicular to the slope were separation force; the fluid force and component of gravity parallel to the slope were competitive force. The interaction force between particles was significant in the case of the very fine particles (<2μm).Separation of hematite and quartz, as an example, calculating various forces of the particles in different sizes and inclined angles, and analyzing the method and conditions of particles captured. The fraction of hematite captured decreases with decreasing the angle. Increasing rotational speed, lengthening magnetic medium and reducing the flow thickness were conducive to the capture of the particles.The intensity magnetic separation tailings as a real sample, were treated by HGPMSIC, the contents of TFe was 17.92%, and mainly existed in hematite, limonite, siderite and other weakly magnetic minerals. The operating parameters were inclined angle (5～45°) and rotational speed (4～20r/min) of HGPMSIC. The grade of magnetic concentrate increased with the increment of inclined angle, and decreased by increasing rotational speed; the recovery increased as the angle decreased, and the rotational speed had an optimal value, at which the recovery was highest. After a magnetic separation, the grade of concentrate was up to 33.18%, the recovery was 41.60%. So the HGPMSIC had a practical effect on treating the tailings.It shows that the test results were consistent with the design principle; therefore, the design of HGPMSIC was reasonable.The finite element analysis of magnetic system and magnetic medium of HGPMSIC were conducted by software ANSYS, which can realize the magnetic properties of the magnetic system and magnetic medium intuitively. The magnetic properties of magnetic medium with different shapes and sizes were also analyzed comparatively. Consequently, the magnetic system and magnetic medium of HGPMSIC can be optimized by finite element simulation analysis to reduce the development costs of this device.