Comparative study on grinding kinetics behavior of vanadium-titanium magnetite ore before and after microwave pretreatment

Abstract

Vanadium-titanium magnetite underwent closed circuit crushing before and after microwave pretreatment. Subsequently, batch grinding tests were conducted on the crushed products, with varying grinding times. Ultimately, the m-order grinding kinetics model of the ore was established both before and after microwave pretreatment. The results show that microwave pretreatment causes a significant increase in the number of micro-cracks on the ore's surface. Moreover, the specific surface area and pore volume of the ore increase by 17.29% and 40.98% respectively. These changes result in a reduction in the mechanical properties of the ore. During the grinding tests, the number of micro-cracks is found to be the primary factor influencing the grinding speed in the initial stage. However, as the grinding progresses, the grinding probability becomes the main factor affecting the grinding speed. The coarse particle size of the microwave-treated ore exhibits a significantly higher grinding speed than the untreated ore. Conversely, the grinding speed of fine particle size ore change slightly. The application of microwave-assisted grinding for vanadium-titanium magnetite proves advantageous in improving the particle size composition of the grinding product. Consequently, this can lead to enhanced separation efficiency and concentrate quality.