Extraction of vanadium(Ⅳ) from sulphate acid solution was studied using organophosphorous-based extractants D2EHPA,EHEHPA and CYANEX 272 in kerosene.The different parameters affecting the extraction of vanadium(Ⅳ) under equilibrium conditions were separately investigated to elucidate the stoichiometry of the extracted species.The distribution ratio of vanadium increased with increasing equilibrium pH of the aqueous phase,concentration of the extractants and temperature.D2EHPA was found to be a stronger extractant,having greater pH functionality than EHEHPA and CYANEX 272.Extraction of vanadium(Ⅳ) by these organophosphorous-based extractants involved cation exchange mechanism,and the extracted species appear to be VORz(HR)2 in the low equilibrium pH and VOR2 in the higher equilibrium pH,where HR refers to the three acidic extractants.%采用有机磷类萃取剂-D2EHPA,EHEHPA和CYANEX272在煤油体系中从硫酸介质中萃取钒(Ⅳ).考察溶液pH值、萃取剂浓度、钒离子浓度、温度对钒萃取性能的影响,并确定萃合物的组成.结果表明:随着水相pH值、萃取剂浓度和温度的升高,钒(Ⅳ)的分配比增大.D2EHPA可以在更低的pH值下萃取钒(Ⅳ),表明其对钒的萃取能力大于EHEHPA和CYANEX272.萃取机理研究结果表明:3种有机磷类萃取剂对钒的萃取均符合离子交换机理,在低pH值条件下萃合物组成为VOR2(HR)2,在高pH值下萃合物组成为VOR2 (R表示萃取剂).
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