赤泥酸浸提钒

Leaching of Red Mud with Different Acids for Extraction of Vanadium

采用H2SO4,HCl,HNO3三种浸出剂提取赤泥中的钒,考察了酸浓度对钒浸出率的影响,对赤泥、浸出液和浸出渣进行了分析,研究了钒溶液的热力学,绘制了不同价态钒浓度对数与pH值关系图.结果表明,H2SO4最适合赤泥酸浸提钒,在液固比5 mL/g、反应温度90℃、反应时间1 h和H2SO4浓度5.5 mol/L条件下,钒浸出率为88%.经H2SO4浸出后,赤泥中的板钛矿、钙钛矿、白云石、赤铁矿和白云母均一定程度溶解,出现硬石膏物相.浸出液pH=0.47,溶液呈蓝色,钒呈4价,钒浓度为0.006773 mol/L,赤泥中的V(IV)与SO42-形成VOSO4,提高了钒的溶解度,拓宽了其稳定存在区间.随H2SO4浓度升高,VO2更易溶解且溶解产物VOSO4更稳定.

Leaching of vanadium from red mud with different acids was carried out, and the effect of acid concentration on the recovery rate of vanadium studied. Furthermore, the red mud, leaching solution and leaching slag were analyzed, the thermodynamics of vanadium solution in sulfuric acid medium was analyzed under standard conditions, where the diagrams of concentration logarithm-pH value under different valence vanadium were drawn. The results show that sulfuric acid was more suitable for recovery of vanadium from red mud. The recovery rate of vanadium could reach 88% under the conditions of ratio liquid to solid of 5 mL/g, reaction temperature of 90 ℃, reaction time of 1 h and sulfuric acid concentration of 5.5 mol/L. The brookite, perovskite, dolomite, hematite and muscovite were dissolved at a certain degree and the anhydrite phase appeared after leaching of red mud with sulfuric acid. The results of pH value of 0.47, colour of blue, valence state of four and vanadium concentration of 0.006773 mol/L were obtained in the leaching system. VOSO4 was generated from V（IV） in sulfuric acid medium, which could increase the solubility of vanadium and broaden its stability range. Furthermore, VO2 was easier to dissolve and VOSO4 more stable with increasing of sulfuric acid concentration.