Study on microwave-assisted grinding and liberation characteristics for Ludwigite

Abstract To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of −75 μm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 μm, both of which were larger than microwave-treated samples. The particle-size distribution of the grinding products for treated ore was more uniform, and the amount of coarse and over-ground particles decreased significantly. The specific surface area, pore volume and pore diameter of the large particles were effectively increased after microwave heating, which improved the crushing and grinding characteristics of the grinding products by lowering the relevant mechanical properties. The monomer liberations of magnetite, ascharite and serpentine of microwave-treated ore samples were 55.33%, 35.48% and 74.98%, respectively, which represented an increase of 12.06%, 9.37% and 6.22% in comparison to untreated ore samples. The bonding characteristics among different minerals were altered through microwave treatment to weaken the bonding force and reduce the proportion of interlocked minerals, which allows these complex minerals to easily liberate after secondary grinding.