Vanadium Extraction from Vanadium-chromium Solution by Hydrothermal-hydrolysis Precipitation

Efficient extraction and separation of vanadium from vanadium solution containing high concentration of chromium and sodium was investigated by hydrothermal-hydrolysis method to solve the treatment difficulties of wastewater with high concentration of Na⁺ and NH₄⁺ produced in traditional vanadium precipitation by ammonium salts and provide favorable conditions for the following chromium extraction,according to the characteristics of vanadium-chromium solution obtained by process of sodium roasting-water leaching of high-chromium vanadium slag for vanadium and chromium extraction.The relationship between parameters （hydrolysis temperature,p H and reaction time） and rates of vanadium precipitation and chromium loss was studied.The results show that near 90% of vanadium precipitation rate and vanadium pentoxide （V₂O₅） satisfying YB/T 5304—2011 standard which is produced by calcination of the waterwashed hydrolysis product can be obtained with reaction at 120 ℃ for 180 min in p H = 1.8 system.