Application of instantaneous power draw analysis to investigate the impact of microwave heating on kimberlite ore crushing

Abstract

Traditional crushing methods rely on a limited number of existing natural cracks as the source of crack propagation to break ore particles. Microwave-assisted crushing, on the other hand, facilitates the crushing process by inducing intergranular and transgranular cracks in ore particles. This not only reduces the energy consumption of the crusher but also improves the production rate of the process. In this study, microwave-assisted crushing of kimberlite ore is investigated ingeniously by examining the change in power draw trends to understand better the roles of larger cracks and smaller cracks induced by microwave treatment. An innovative calculation method is proposed to enable continuous monitoring of power draw instead of average power consumption. This method establishes a quantitative standard for exploring ore crushing capacity and the mechanisms of rock samples. From this study, the cumulative specific crushing energy and crushing time reduction in microwave-treated samples can be attributed to three distinct mechanisms. Firstly, the preferential generation of comparatively bigger cracks on large particles improves the breakage rate within the accumulating zone. Secondly, the generation of sufficient comparatively smaller cracks on large particles contributes to a lower peak net power amplitude. Lastly, the well-distributed generation of cracks across all particle sizes results in a shorter declining zone and an overall improvement in crushing time. The most significant reduction in both crushing energy and crushing rate is observed with the high microwave energy input. However, even at lower microwave energy inputs, substantial reductions in specific crushing energy and crushing time can still be achieved. This study demonstrates that the proposed method can be applied to other comminution systems, whether with or without microwave assistance.