China Nonferrous Metallurgy

Microwave intervention in the grinding and leaching process of vanadium-bearing shale has a positive effect on reducing grinding energy consumption and improving leaching efficiency and leaching rate. This study conducted experimental comparisons between conventional grinding leaching and microwave grinding leaching conditions, and studied the microwave strengthening mechanism through microscopic morphology analysis technology and COMOSL electromagnetic thermal stress simulation. The conditional experiment shows that after microwave intervention in grinding and leaching, the grinding time can be shortened by 33.33%, saving about 31.06% of grinding energy consumption, increasing the vanadium recovery rate by 6.18%, and shortening the leaching time by 79.17%. The COMSOL simulation results indicate that when vanadium shale particles come into contact with each other, electric field polarization occurs, generating high-temperature hot spots of 300~2500℃, which damage the mineral structure; at the same time, due to the different dielectric properties between mineral components, their heating rates also vary, which will result in a temperature difference of 500~2000℃ and a thermal stress of 4.87~78.5GPa, leading to heterogeneous dissociation and increasing the grindability of vanadium shale. There are also high temperature hot spots in the process of microwave assisted leaching. Local high temperature destroys the mineral structure and refines the particle size of minerals. With the increase of exposed surface of vanadium bearing minerals, the collision frequency between hydrogen ions and active site increases, accelerating the dissolution of vanadium. This study can provide theoretical basis and reference for the microwave assisted grinding leaching process.