Selective recovery of vanadium from high-chromium vanadium slag by a mechanically activated low-sodium salt roasting-water leaching process

Stabilizing the toxic element chromium and improving vanadium recovery are crucial for the economic and efficient treatment of high chromium-bearing vanadium slag. This study employed mechanical activation to enhance vanadium extraction from high chromium-bearing vanadium slag through a low-sodium salt roasting-water leaching process. The effects of Na2CO3 addition, roasting temperature, and roasting time were investigated to determine the optimal roasting parameters. Subsequently, the effects of mechanical activation on the morphological and microstructural changes were characterized using a laser diffraction particle size analyzer, a micropore physisorption analyzer, scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The effects of mechanical activation on the extraction of vanadium and chromium were determined by leaching the roasted samples after varying activation times. The results indicated that mechanical activation decreased particle size, increased surface area, and enhanced the activity of the samples. The leaching results demonstrated that mechanical activation enhanced the leaching efficiency of vanadium by 5 %, reduced the optimum roasting temperature by 50 ℃, and slightly increased the leaching efficiency of chromium by 0.5–1 %. [Display omitted] •High Chrome Vanadium slag requires mechanical activation.•The leaching rate of V reached 94 % and the leaching rate of Cr was less than 7 %.•A significant amount of Cr is stabilised in the vanadium tailings in a non-water soluble state.•Effective in reducing environmental pollution from V and Cr.