The Development Of Permanent High Gradient Magnetic Separator

Magnetic separation is one kind of simple and effective material processing method, which can avoid the pollution caused by chemical method and has low cost. It must find more and more application because of the character of our country's iron ore resource, namely low grade finely disseminated and lots of valueable elements associated, and of the growing demand for high grade industry mineral for the future.The high gradient magnetic separator is one of the most important equipment to process weak magnetic hematite. It can recover the magnetic mineral by the greatest degree under a suitable grinding fineness, and then an ultimate concentrate will be obtained after being treated by reverse flotation. At present the widely used HGMS is the electromagnetic pulsation high gradient magnetic separator, and its background field intensity may reach above 1.0T, unfortunately with a high consumption of electricity and water. At the foundation of development of magnetic material industry, this paper designed a permanent magnetism high gradient magnetic separator. The background magnetic field intensity can be up to 0.65～0.75T with NdFeB, and it uses stainless steel rods with high permeability as magnetic media, the surficial magnetic induction of which will reach 1.2T.The main units in PHGM include a cylinder, the trough body, feeding unit, unloading unit, supporting, gearing and a frequency conversion speeder. Magnetic systerm has a curve surface, with the magnetic poles alternately arranged axially, and with an arc of 180°in the radial direction. The media can be magnetized when passing through magnetic field. The pulp is feeded through feeding unit. Magneitic particles are captured by media and transported to region without field and collected in the concentrate area by washing water. Nonmagnetic fraction falls directly into tailing area through the splits between the media. The total mass of PHGM is 1193kg with power of 3.0kW, and a simple structure, and operated conveniently.Under the conditions of grinding fineness approximately 80% of -0.074mm, 30%～40%of ore density,3r/min～5r/min of rotational speed of tube body, 0.15MPa of the hydraulic pressure,3.5kg/min of the feed, a Fe concentrate has been obtained with grade of 40.21%, recovery of 73.84% in the separation of hematite from Anshan with Fe grade of 26.65% by the PHGM. And one other Fe concentrate has been obtained with grade of 45.57%, recovery of 70.34% in the separation of the same sample by the PHGM first and then HGMS. And moreover the HGMS'load is reduced by 60% in the process, which improves the working efficiency greatly.The development of permanent magnetism high gradient magnetic separator is conducted in this paper and its separation mechanism is discussed. A good separating performance can be received by the PHGM from experiments. It gives a new basis for the separating of weak magnetic mineral such as hematite and for the permanent magnetism of the high gradient magnetic separation equipment.