The Study On Direct Extracting Vanadium From Vanadium-Titanium Magnetite Concentrate

In the vanadium extraction process by means of sodium roasting and water leaching, calcium and vanadium can generate calcium vanadate which has low water solubility and is not beneficial to water leaching process. To vanadium materials with high calcium, it can cause some vanadium loss and bring severe environmental pollution. So calcium be regarded as harmful ingredients. In order to solve the above problems, this paper deals with the study on the vanadium extraction process by calcium roasting and acid leaching from vanadium-titanium magnetite concentrate, and proposes a clean process.Magnetic separation results show that:When the particle size is between200and300mesh and the magnetic field intensity is1.7A, the total ferrum content is highest and up to52%, the vanadium recovery rate comes up to95%, and the silica content falls to4.07%.Calcium roasting results indicate that:(1) High temperature is conducive to the roasting reaction, and the suitable addition amount of calcium carbonate is7%. For static test, material shape does not affect roasting results, and when the roasting temperature come up to1150℃, vanadium leaching rate can reach80%. For dynamic test, because of better oxygenation environment, when the roasting temperature is1100℃, vanadium leaching rate can reach80%, and at the same time vanadium leaching rate has nothing to do with grain size and the binder type.(2) In contrast to sodium roasting, calcium roasting needs the higher temperature; Both vanadium leaching rate are more or less the same and a little higher than80%.Leaching test shows that:(1) Comprehensively considering the impurities content, energy consumption and other factors, the appropriate leaching condition is that pH=2.0, leaching time t=3h, leaching particle size being200-300mesh, S:L=1:2.(2) Adjust the pH value of leaching solution by adding roasting clinker and mixing, then heat the solution. When its volume reduce by half, the solution is filtered. At this time, vanadium, phosphorus and silicon content in the filtrate all can correspond with the requirements of vanadium precipitation.The precipitation of vanadium results showes that:Ammonium ployvanadate can be abtained by adding ammonium sulfate to rich vanadium solution in acid condition. The optimum technology condition is determined to be that pH=2.0-2.5, precipitation temperature T=90℃, precipitation time t=30min, the ammonificatin coefficient K=3.0. After roasted, the product purity of vanadium pentoxide is98.3%, and its quality achieves national standards (GB3283-87).