Study On Fine Coal Strong Permanent Magnet Magnetic Filter

The resource endowment, which is poor in oil and lacks natural gas but is rich in coal, China's energy energy constitution is determined by coal, and combustion is used as the most important utilizing form, both which result in china becoming a typical coal-burning air pollution country. Dry-type strong magnetic separation technology is a source control technology, pollution-free, low cost, which is considered to be ideal way to effectively alleviate air pollution caused by coal-burning in China. Permanent magnetic separation has a huge advantage in the energy-saving, but the research of combining pulverized coal dry separation desulfurization with the permanent magnet magnetic separation is not much yet, and at home and abroad there isn't magnetic separation equipment for sorting the very weak magnetic susceptibility powder of pyrite in coal. This paper has carried out pulverized coal dry strong magnetic separation related research by taking advantage of MagNet software. Firstly, the theoretical research typical permanent magnetic systems were carried out, on that basis putting forward the multi-multidimensional permanent magnet magnetic system by optimization and combination of different magnetization directions and specifications of the NdFeB using adopting extrusion and cladding magnet technologies, and designing assembly equipment for, and the special equipment prototype was explored. The sorting experiment has been made using equipment prototype, and then this magnetic system have been studied using MagNet software. In the end a structure optimal parameter configuration was presented. The research results show that: MagNet software can stimulate reliable numerical results, which provides an effective means for the magnetic system design and optimization. When designing and configurating magnetic system, extrusion and cladding magnet technologies can be used to improve the magnetic field strength, and closed magnetic circuit structures should be given priority. As configurating separation space of magnetic system, the force of magnetic particles in the lateral is bigger than that in the vertical direction. The fine coal expriment of dry permanent magnet magnetic separation has chieved noticeable results using the designed new high field strength permanent magnet magnetic filter.Sulfur reductions of 44% and ash reductions of 43%, respectively were obtained, while the clean coal yield reaches 95.61%, correspondingly the size is 0.15~0.074mm.The separation effeciency is almost equal to the Nantong coal of wet centrifugal gravity separation and Cha Zhuang coal of electromagnetic wet separation, which provide an experimental basis for the study on permanent magnet dry magnetic separation of fine coal deash and desulphurization technologies.To further understand the magnetic field characteristics of this new type of magnetic system, the energy functional of the corresponding magnetic field numerical solution is established.Magnet simulation shows that Extruding magnet soft iron to conduct magnetism and sheathing magnet to gather magnetism indicate a good effect, magnetic field strength has been improved significantly.When soft iron thickness of 4mm and diameter ratio of ring magnet(diameter ratio of ring magnet) 10/3, simulated maximum magnetic field strength ofφ29.2mm separation space is up to 3.298T. While the average of the maximum magnetic field strength can be up to 1.5T (measured value of 1.3T), It prove that magnetic circuit design is basically reasonable. The structural parameter optimization of magnetic system showed that thickness ratio of soft iron and the ring magnet has a big influence on the magnetic field strength and exists an optimal ratio between them. The magnetic field strength first increases and then decreases along with increasing of thickness ratio of soft iron and ring magnet ranging from 1:20 to 1:4. Diameter ratio of ring magnet has little effect on the magnetic field strength changes.The the extention length of soft iron has an impact on the magnetic field strength, soft iron extending out the magnetic separation space,can play the role of gathering magnetism.The magnetic field strength increases with the extention length of soft iron in the separation space, but the trend of increasing gradually becomes slow. And extension length of soft iron is to be limited because of restrictions on the separation space. The magnetic field strength and gradient is both high near the magnetic matrix.The higher background magnetic field strength of separation areas, the more significantly the magnetic field inhomogeneity of the separation areas after adding in magnetic matrix, and the magnetic field gradient is also greater. The optimization results provides theoretical basis for studying on such a magnetic filter magnetic system.