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研究了硫酸体系中质子化的叔胺类萃取剂N235对钒萃取性能的影响及萃取机制。实验过程中考察了萃取振荡时间、水相初始p H、萃取剂浓度、SO2-4浓度对钒萃取性能的影响。结果表明:在有机相组成为5%N235+5%仲辛醇+90%磺化煤油,相比(O/A)为1∶2的条件下,N235萃取钒的平衡时间为2 min;水相初始p H在2.5~4.0之间时,钒的萃取率随初始p H的增大略微下降;当初始p H为2.5时,钒的萃取率达到最大,为94.46%。SO2-4离子浓度对萃取率有一定的影响,萃取率随其浓度的增加而减小;萃取率随着N235初始浓度的增加而增大,浓度过大不利于萃取过程的进行。当水相p H为2.0~4.0时,水相中钒主要以H2V10O4-28,HV10O5-28等络合阴离子形式存在。采用饱和容量法和等摩尔系列法研究了N235对钒的萃取机制,当水相平衡p H值为2.0时,萃合物中钒与N235的摩尔比,即萃合比([V]/[N235])为2.5;平衡p H为4.0时,萃合比为2.0,并分别得到了相应的萃取方程。
The effect of protonated tertiary amine extractant N235 on the extraction of vanadium and the extraction mechanism were studied. The effects of extraction oscillation time, initial pH of aqueous phase, extractant concentration and SO2-4 concentration on the extraction performance of vanadium were investigated. The results showed that the equilibration time of N235 extracting vanadium was 2 min when the organic phase consisted of 5% N235 + 5% sec-octanol + 90% sulfonated kerosene and the O / A ratio was 1: 2. When the initial phase p H is between 2.5 and 4.0, the extraction rate of vanadium decreases slightly with the increase of initial p H; when the initial p H is 2.5, the maximum extraction rate of vanadium is 94.46%. The concentration of SO2-4 had a certain influence on the extraction rate. The extraction rate decreased with the increase of its concentration. The extraction rate increased with the initial concentration of N235. The concentration was too large to be conducive to the extraction process. When the water phase p H is 2.0-4.0, vanadium in the aqueous phase mainly exists as complex anions such as H2V10O4-28 and HV10O5-28. The extraction mechanism of vanadium by N235 was studied by the saturated volumetric method and the equimolar series method. The molar ratio of vanadium to N235 in the extract was (V / N235]) was 2.5. When the equilibrium p H was 4.0, the extraction ratio was 2.0, and the corresponding extraction equations were obtained.