离子液体[Emim]PF_6-邻二氮菲超声萃取铁尾矿中的铁

Ultrasonic Extraction of Trace Iron in Iron Tailings with Ionic Liquid [Emim]PF_6-Phenanthroline

铁尾矿不仅造成资源的浪费,同时也给环境带来严重的污染。针对铁尾矿具有组分复杂且铁含量较低的特点,本文采用离子液体[Emim]PF6-邻二氮菲超声萃取分离体系,对铁尾矿样品中的铁进行萃取。为提高铁尾矿中铁的萃取率,考察了离子液体用量、温度、pH值等萃取条件对萃取率的影响。结果表明,在萃取体系中加入0.8 mL邻二氮菲、1.0 mL离子液,控制温度80℃、pH值为7.3、萃取时间为30 min时,铁矿泥中微量铁的萃取率可达92.74%,而且共存离子K+、Na+、Ca2+、Mg2+、Zn2+不影响水相中铁的测定。对使用后的离子液体进行反萃取研究发现,当反萃取时的pH>11时,回收的离子液体稳定性降低;而低温加热对使用后的离子液体反萃取影响较小,使用后的离子液体经NaOH处理回收,其红外谱图与使用前基本一致,表明回收的离子液体可重复使用。与传统的液液萃取方法相比,本萃取方法具有离子液体用量少、萃取率高、易回收等特点,可用于铁尾矿中金属铁的回收利用。

Iron tailings are not only a waste of resource, but also bring serious environmental pollution. On account of the complex components and lower iron content in iron tailings, the ultrasonic extraction system of ionic liquid [ Emim] PF6-phenanthroline to extract trace iron from iron mud samples has been improved and the method is described in this paper. In order to improve the iron extraction rate from iron railings, the effect factors were studied, such as the ionic liquid dosage, temperature and pH value on the extraction rate. The results show that the extraction rate of the trace iron from iron mud reached 92.74% under the addition of 0.8 mL phenanthroline, 1.0 mL ionic liquid, and the pH value was 7.3 when the extraction time was 30 minutes at 80℃. Moreover, the coexistence ions of K ^＋ , Na^＋, Ca^2＋, Mg^2＋ and Zn^2＋ had no effect on iron determination. Meanwhile, the back extraction study for the used ionic liquid revealed that the stability of the recovered ionic liquid was lowered when the pH value was more than 11. However, low temperature heating had relatively slight effects for back extraction on the used ionic liquid. The used ionic liquid can be treated and recovered with NaOH solution and the infrared spectrogram remained almost the same as the new ones, which can be reused after the recovery. Compared with the traditional methods of liquid-liquid extraction, this method has the advantages of lower dosage of ionic liquid, higher rate of extraction and easier recovery, and it can be applied to the recovery of the iron from iron tailings.