The potential of ultrasonic pretreatment enhancing selective surface dissolution to improve the floatability of spodumene with different size fractions was verified and investigated. For coarse particles of −0.15 + 0.0385 mm, compared with traditional pretreatment methods, ultrasonic pretreatment could optimize the physicochemical properties of the surface, markedly increased the amount of NaOL adsorbed on the mineral surface, and improved the floatability of the spodumene. For fine particles of −0.0385 mm, both pretreatment methods (Ultrasonic and Traditional) could greatly increase the flotation recovery, but ultrasonic pretreatment had no obvious advantage compared with traditional method. ICP combined with XPS analysis were conducted to investigate the dissolution mechanism of spodumene surface in different pretreatment system. Si species on the surface of coarse particles were easily dissolved into the solution under the effect of ultrasound, which increases the relative content of Al and Li species on the surface. This was conducive to the adsorption of the collectors on the surface. However, the selective dissolution of the fine particle surface was weakened by excessive energy intake in the ultrasonic system, which neutralized the advantage brought by the large amount of dissolution, making the results obtained by the two preprocessing methods the same.

Dry permanent magnetic separators have been widely used in the mineral and coal processing industries due to their simple operation and high separation efficiency. These tools not only discard some amount of bulk gangue from the raw ore, thereby reducing the volume of the grinding operation and cutting energy consumption, but also do not require water in the sorting process, thereby expanding their applicability to arid and cold areas. With the depletion of global iron ore resources, a dry, low-cost processing or pre-sorting prior to the wet separation has received the attention of industrial practitioners as a potential alternative. The performance of dry magnetic separators plays a critical role in dry processing This paper reviews the dry magnetic separators available in the literature and describes their operating principles, separation performance, and applications. A detailed comparison of different separators is also conducted to evaluate the differences in their sorting performance and mechanisms and to provide a reference for the optimization of dry magnetic separators.