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Three factors affecting the selection of dry magnetic separator

Date:2020-05-27 12:05:47

Dry magnetic separator is suitable for magnetite, magnetic pyrite, roasted ore, ilmenite and other materials with a particle size of less than 3mm. It is also used for iron removal of coal, non-metallic ore, and building materials.


1. Thickness of the feed layer: it has a great relationship with the particle size of the raw material to be processed and the content of magnetic particles. The coarse feed layer is generally thicker than the fine particles. When processing coarse-grained ore, the thickness of the ore-feeding layer is about 1.5 times that of the largest particle. It can process about 4 times of the largest particle in the middle particle size, and up to 10 particles in the thickness of fine particle material. When the content of magnetic materials in the raw materials is not high, the feed layer should be thinner. If it is too thick, the magnetic particles in the lowermost layer are under the pressure of the upper layer material, and the magnetic force cannot be absorbed, causing the recovery rate to decrease. When the content of magnetic particles is high, the ore-feeding layer may be thicker.
2. Magnetic field strength and working clearance: it is closely related to the particle size, magnetic height and operation requirements of the processed materials. When the working clearance is fixed, the magnetic field strength between the poles is determined by the ampere turns of the coil, and the turns cannot be adjusted, so the magnetic field strength can only be adjusted by changing the magnitude of the exciting current. When dealing with the cleaning operations such as Hongzun with strong magnetism, the weak magnetic field should be used, and the materials with weak magnetism and the cleaning operations should be handled. The field strength should be higher. When the current is fixed, changing the size of the working gap can not only change the strength of the magnetic field, but also change the gradient of the magnetic field, so as to reduce the sharp increase of the gap magnetic force. Generally, the size of the treated particles should be minimized in order to increase the recovery rate. During cleaning, it is better to increase the gap to increase selectivity and grade, but at the same time, the magnetizing current should be increased properly to ensure the required magnetic field strength.
3. Feeding rate: The feeding rate is determined according to the speed of the vibration tank (or belt). Its speed determines the mechanical force of the time when the ore particles are stopped in the magnetic field. The greater the rate, the shorter the ore particles are stopped in the magnetic field. The mechanical forces received by the ore particles are mainly gravity and inertial knives. Constant, inertial force is proportional to the square of velocity. The magnetic force of the weak magnetic ore particles in the magnetic field surpasses the gravity, so the rate exceeds a certain limit. Because the inertial force increases, the absorbed magnetic force will be insufficient, causing the acceptance rate to drop. Therefore, when selecting weak magnetic minerals, it is advisable to adopt a feeding rate lower than that of strong magnetic minerals. As usual, when selecting, there are more monomer particles in the quality guess, and the magnetism is stronger. The feed rate can be increased. When scanning, the quality guess contains more contiguous bodies and the magnetism is weaker, which is an improvement. The acceptance rate should be lower for the mine rate; when disposing of fine particles, in order to facilitate the loosening of the ore particles, the frequency of the vibration tank should be higher and the amplitude is smaller; when disposing of coarse particles, the opposite is true. Appropriate operating conditions should be determined through implementation based on the ore nature and the requirements for sorting quality. When disposing of a large number of metal ores, the materials should be connected to dry and narrow grade ore feeding, which is conducive to the progress of the index. The experience shows that the more sieving grades of raw particles, the better the indicators.




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