Vanadium Extraction by Sodium-Manganese Composite Roasting from Vanadium-Containing Refining Tailings of Titanium Tetrachloride

To explore the extraction and utilization of vanadium resources from titanium tetrachloride purification tailings, sodium-manganese composite roasting and oxalic acid leaching, a new process for vanadium extraction, and proposed based on a thermodynamic analysis of the roasting process. This study focuses on investigating the influence of various factors, including the solid-liquid ratio of the wash solution, roasting temperature, MnO/V2O5 molar ratio, and NaCl addition, on the phase composition of the roasted clinker and the vanadium leaching rate. Leaching kinetics were further explored after determining the optimal process conditions. NaCl-MnCO3 composite roasting effectively alters the phase composition of vanadium, lowering the experimental roasting temperature and reducing the amount of sodium salt required. The optimal experimental conditions were determined as follows: roasting temperature of 750 degrees C, roasting time of 2 h, 6% NaCl addition, MnO/V2O5 molar ratio of 1.5, liquid-solid ratio of 10:1 mL/g for leaching, leaching temperature of 50 degrees C, oxalic acid solution pH 2.5, and leaching time of 30 min. Under these conditions, the V leaching rate achieved was 96.65% using the NaCl-MnCO3 composite roasting method, representing an increase of nearly 19% compared to using MnCO3 alone as the roasting salt, and an increase of nearly 25% compared to using NaCl alone. The V leaching process follows the nuclear shrinkage model, which is controlled by both chemical reaction and diffusion mechanisms. The apparent activation energy of this process is 40.83 kJ/mol.