The influence of magnetic field frequency on eddy current separation

Solid waste contains a large amount of non-ferrous metal resources. Eddy current separation can separate and enrich them. Increasing the eddy current force of is the key to improving efficient separation. The alternating magnetic field frequency plays an important role in regulating the eddy current force. It includes the magnetic roller speed and pole pair configuration. In this study, based on electromagnetic field theory and COMSOL Multiphysics simulation, the influences of the magnetic roller speed and pole pair configuration on the eddy current force of particles with different radii are investigated. And eddy current mechanism and magnetic field mechanism are revealed to explain the relationship between the magnetic roller speed, the pole pair configuration and eddy current force, respectively. Study shows that the optimal magnetic roller speed decreases as the particle size increases and the optimal pole pair configuration is 6 pairs for separating particles with the radii of 2 ~ 16 mm. The results are beneficial for the magnetic roller design and production cost reduction, which will be used to separate larger size range materials. And they also can guide the setting of optimal operating parameters according to the particle sizes.

固体废物中蕴藏着大量的有色金属资源，涡流分选技术可对其进行分离与富集。提升涡流作用力是实现高效分选的核心关键。交变磁场频率在涡流作用力的调控中发挥着重要作用，其调控要素涵盖磁辊转速与极对数配置。本研究基于电磁场理论与COMSOL Multiphysics（多物理场仿真软件）仿真，探究了磁辊转速与极对数配置对不同粒径颗粒涡流作用力的影响规律，并分别通过涡流作用机制与磁场作用机制，阐释了磁辊转速、极对数配置与涡流作用力三者间的关联。研究结果表明，最优磁辊转速随颗粒粒径增大而降低；针对粒径2~16mm的颗粒进行分选时，最优极对数配置为6对。该成果有助于磁辊的设计优化与生产成本管控，可用于分选更广粒径范围的物料，同时也能指导根据颗粒粒径设置最优运行参数。