Process and Kinetic Assessment of Vanadium Extraction from Vanadium Slag Using Calcification Roasting and Sodium Carbonate Leaching

The leaching process of vanadium from the calcification-roasted vanadium slag by sodium carbonate was researched. The effect of the main parameters on the sodium carbonate leaching process was investigated, and a kinetics analysis for the process using a new shrinking core model is presented. The results indicate that the leaching rate of vanadium significantly depends on the leaching temperature. Under the conditions of 6% CaO additive content in the roasted samples, 10:1 ml g(-1) liquid-solid ratio, 80 g L-1 Na2CO3, and 30 min at 90 degrees C, the leaching rate of vanadium is 86.64%. The clean and efficient utilization of vanadium slag can be achieved by the calcification roasting and sodium carbonate leaching process. Scanning electron microscopy/energy dispersive x-ray spectroscopy analysis shows that the vanadium slag can be effectively leached by sodium carbonate with few impurities drawn into the solution. The leaching kinetics of this process shows that the interfacial transfer and diffusion across the product layer affect the leaching at the same time. Moreover, the calculated activation energy of the leaching process is 40.93 kJ/mol, and the reaction order of the sodium carbonate concentration is 0.49.