单长链烷基酸性磷酸酯对锆的萃取和保留

EXTRACTION AND RETENTION BEHAVIOUR OF ZIRCONIUM BY MONOALKYL LONG CHAIN ACIDIC PHOSPHATE

本文研究了在30％TBP-单长链烷基酸性磷酸酯(MLCAP)-煤油-HNO_3和MLCAP-煤油-HNO_3两个体系中,萃取剂浓度、水相中H^+、总NO_3^-、稳定锆和铀的浓度及温度等因素对Zr的萃取行为和酸、碱洗涤后Zr的保留行为的影响。还对萃取反应机制进行了初步探讨。结果表明,在实验条件下,MLCAP与Zr生成组成为2:1的萃合物;当MLCAP存在于30％TBP-煤油中时,会使Zr的萃取明显增加并易产生界面物;在用Na_2CO_3洗涤有机相时,不能将Zr有效洗脱并易产生乳化现象,使溶剂质量变坏和造成分相困难。乳化生成的程度与体系中稳定锆的浓度和MLCAP的存在量有关。

The extraction behaviour of Zr in 30% TBP-monoalkyl long chain acidic phosphate (MLCAP) -kerosene-HNO3 and MLCAP-kerosene-HNO3 system is studied. The retentive percentage of Zr in organic phase scrubbed by 0.01 mol/1 HNO3 and 5% NaCO3 solution is determined. The mechanism of extraction of Zr by MLCAP is also studied preliminarily. The results indicate that the Zr:MLCAP is equal to 1=2 in the extracted complex. While MLCAP is present in 30% TBP-kerosene-HNO3 system, the distribution coefficient of Zr increases significantly and the tendency toward forming interfacial crude increases. The formed complexes are scrubbed difficultly by 0.01mol/1 HNO3 and 5% Na2CO3 solution and emulsification easily induced. The emulsion extent depends on the concentrations of Zr and MLCAP. The presence of MLCAP with concentration as low as 2×10-4mol/l can lead to serious phase separation problem when the solvent is contacted with 5% Na2CO3 solution even though the concentration of Zr is of trace amount.