杂质离子对萃取法从石煤酸浸液中分离纯化钒的影响

含钒石煤经焙烧、硫酸浸出后,酸浸液中含有高浓度的Fe3+、Fe2+、Al 3+和Mg2+等杂质离子。以D2EHPA和TBP为萃取剂,磺化煤油为稀释剂,采用萃取法对该酸浸液进行钒的提纯试验,考察杂质离子对钒萃取率的影响。结果表明,在配制的纯溶液中,V4+的萃取率明显高于V5+;Fe3+质量浓度大于5g/L时会显著降低V4+萃取率;Al 3+和Mg2+的质量浓度低于10g/L时,其共萃率明显降低。对实际酸浸液进行还原处理后,99%的V4+能够被萃取回收,而大部分Fe2+、Al 3+和Mg2+则存在于萃余液中。少数共萃的Fe2+在反萃作业后留在贫有机相中,Al 3+和Mg2+在沉钒后留在沉钒尾水中,不影响V2O5纯度。

Effect of Impurities on Vanadium Purification from Acid Leaching Solution of Stone Coal with Solvent Extraction Process

Stone coal was roasted and sulfuric acid leached. Separation of vanadium from the vanadium containing solution with impurities of Fe3 , Fe2 , Al3 and Mg2 was conducted through solvent extraction process with D2EHPA and TBP as extractant and sulfonated kerosene as diluent. The effects of impurities on vanadium extraction rate are discussed. The results show that extraction ratio of V4 is higher than that of V5 , and Fe3 has a negative effect on extraction ratio of V4 when its mass concentration exceeds 5 g/L. The co-extraction ratios of Al3 and Mg2 markedly decrease when their mass concentrations are lower than 10 g/L. Extraction experiments with D2EHPA indicates that 99% of V4 can be extracted from the real leaching solution after reduction process, leaving most of Fe2 , Al3 and Mg2 in raffinate. The extracted Fe2 remains in the stripped organic phase, and Al3 and Mg2 remain in the waste water of vanadium precipitation. Pure V2O5 can be obtained.