Optimization of the separation chamber structure of a pneumatic dry low-intensity drum magnetic separator based on a multi-physical field coupling model

Dry magnetic separator is the workhorse for processing fine-grained magnetite in arid and remote regions. In this study, a pneumatic dry low-intensity drum magnetic separator (PDLDMS) with a side vertical upward feeding was designed and optimized based on a multiphysics numerical model. The structural parameters of the separation chamber were designed and optimized by predicting the separation performance and particle dynamic trajectory of the PDLDMS. All predictions indicated that the structural parameters of the separation chamber affected the capture behavior of particles with different sizes and relative magnetic permeability. An appropriate increase in the spacing of the separation chamber was conducive to reducing the entrapment of the particles with a lower relative magnetic permeability and improving the grade of the concentrate. An appropriate increase in the waveform amplitude of the separation chamber was conducive to improving the recovery of the fine-grained particles with a higher relative magnetic permeability and improving the recovery of the concentrate. The optimum PDLDMS performance was achieved at a separation chamber spacing of 40 mm and a separation chamber waveform amplitude of 20 mm. By comparing the experimental results with simulated results, the accuracy of the PDLDMS recovery and grade prediction results were verified.