粉煤灰酸浸溶液中铁铝离子的萃取分离

Extraction and Separation of Iron and Aluminum Ions from Acid Leaching Solution of Fly Ash

采用N503和TBP、正辛醇、煤油组成的复合萃取体系,对粉煤灰酸浸溶液中的铝与铁进行萃取分离,考察盐酸浓度、氯离子浓度、萃取剂比例对Fe3+萃取率的影响,以低浓度HCl溶液反萃负载铁有机相,并通过逆流实验确定最佳工艺条件.结果表明,采用N503:TBP:正辛醇:煤油=3:1:1:5(j)的萃取体系,在初始铁浓度为0.96 mol/L、铝浓度为0.22mol/L、萃取相比O/A=2:1条件下,经5级逆流萃取,Fe3+的萃取率大于99.8%,铝几乎没有损失.用0.01mol/LHCl溶液作反萃剂,反萃相比O/A=2.5:1,经6级逆流反萃,反萃液中铁浓度达1.8mol/L.分析了有机相负载铁前后官能团的红外光谱图.

The extraction and separation of iron and aluminum ions from acid leaching solution of fly ash were carried out in the composite extraction system with N503 and TBP as extractants, n-octanol as modifier and kerosene as diluent. The effects of concentration of HCl in aqueous phase, concentration of chlorine ion and volume fraction of N503 in organic phase on the extraction were examined. And stripping of iron from the iron-loaded organic phase with low HCl solution was conducted and the optimum conditions were obtained by the countercurrent experiments. The results showed that over 99.8% of iron was extracted, but aluminum almost remained unchanged, from the extraction system of 30%（φ） N503, 10%（φ） TBP, 10%（φ） n-octanol and 50%（φ） kerosene under the conditions of initial iron concentration at 0.96 mol/L, aluminum concentration 0.22 mol/L, extractant phase ratio O/A 2：1 and five extraction stages. 0.01 mol/L HCl solution was used as stripping solution, under the stripping conditions of phase ratio O/A at 3：1 and six stripping stages, the iron concentration in the final stripping solution reached 1.8 mol/L. In addition, the FT-IR spectra of both the pure and iron-loaded phases were also presented.