EQUILIBRIUM AND NONEQUILIBRIUM EXTRACTION SEPARATION OF RARE-EARTH-METALS IN PRESENCE OF DIETHYLENETRIAMINEPENTAACETIC ACID IN AQUEOUS-PHASE

被引:14
作者
AZIS, A [1 ]
MATSUYAMA, H [1 ]
TERAMOTO, M [1 ]
机构
[1] KYOTO INST TECHNOL,DEPT CHEM & MAT TECHNOL,SAKYO KU,KYOTO 606,JAPAN
关键词
SOLVENT EXTRACTION; RARE EARTH METAL; DIETHYLENETRIAMINEPENTAACETIC ACID; NONEQUILIBRIUM SEPARATION; ORGANOPHOSPHORUS EXTRACTANT;
D O I
10.1252/jcej.28.601
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
Equilibrium and non-equilibrium extraction separations of rare earth metals were carried out in the presence of chelating agent in the aqueous phase. The separation systems of the rare earth metal mixtures used were Y/Dy, Y/Ho, Y/Er and Y/Tm, and the chelating agent and the extractant were diethylenetriaminepentaacetic acid (DTPA) and bis (2,4,4-trimethylpentyl) phosphinic acid (CYANEXR(R) 272), respectively. For Y/Dy and Y/Ho systems, higher selectivities were obtained in equilibrium separation compared with those in non-equilibrium separation. On the other hand, the selectivities in non-equilibrium separation were higher for Y/Er and Y/Tm systems. In the separation condition suitable to each system, the addition of DTPA to the aqueous phase was found to be very effective for obtaining higher selectivities. The distribution ratios of the rare earth metals and the selectivities in the equilibrium separations obtained experimentally were thoroughly analyzed by considering various equilibria such as the extraction equilibrium and the complex formation equilibrium between rare earth metals and DTPA in the aqueous phase. Moreover, the extraction rates and the selectivities in the non-equilibrium separations were also analyzed by the extraction model considering the dissociation reactions of the rare earth metal-DTPA complexes in the aqueous stagnant layer. Based on these analyses, we presented an index which is useful for selecting the optimum operation mode, that is, for determining whether equilibrium or non-equilibrium separation should be employed. Using this index, we can predict that the selectivities under equilibrium conditions are higher than those under non-equilibrium conditions for Y/Dy and Y/Ho systems, while for Y/Er and Y/Tm systems, higher selectivities are obtained under non-equilibrium conditions. The experimental results were in agreement with predictions by this index. Further, the selectivities in various systems including other chelating agents and extractants were discussed based on this index.
引用
收藏
页码:601 / 608
页数:8
相关论文
共 21 条
[1]   USE OF COMPLEX-FORMING AGENTS FOR EXTRACTION SEPARATION OF CERIUM GROUP OF RARE-EARTH ELEMENTS IN SYSTEMS WITH NEUTRAL ORGANO-PHOSPHORUS EXTRACTANTS [J].
ALFARED, S ;
ZANTUTI, F ;
KRYLOV, YS .
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES, 1988, 125 (02) :381-391
[2]   DISSOCIATION RATES OF VARIOUS HEAVY RARE-EARTH METAL-DIETHYLENETRIAMINEPENTAACETIC ACID COMPLEXES [J].
AZIS, A ;
MATSUYAMA, H ;
TERAMOTO, M .
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1995, 28 (03) :334-339
[4]   EXTRACTION AND SEPARATION OF RARE-EARTH ELEMENTS BY TRI-NORMAL-OCTYLMETHYLAMMONIUM NITRATE AND BETA-DIKETONE USING WATER-SOLUBLE COMPLEXING AGENT [J].
HIRAI, T ;
KOMASAWA, I .
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1991, 24 (06) :731-736
[5]   SYNERGISTIC EXTRACTION OF RARE-EARTH ELEMENTS BY TRI-NORMAL-OCTYLMETHYLAMMONIUM NITRATE AND BETA-DIKETONE [J].
KOMASAWA, I ;
MIYAMURA, M .
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1991, 24 (03) :306-311
[6]   SEPARATION OF CERIUM AND EUROPIUM BY EXTRACTION WITH TRIBUTYL-PHOSPHATE AND DI(2-ETHYLHEXYL)PHOSPHORIC ACID IN N-ALKANE FROM NITRATE SOLUTIONS [J].
KOPUNEC, R ;
KOVALANCIK, J .
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES, 1989, 129 (02) :295-303
[7]   KINETIC-STUDIES OF EXCHANGE-REACTIONS BETWEEN RARE-EARTH METAL-IONS AND THEIR DIETHYLENE-TRIAMINEPENTAACETIC ACID COMPLEXES [J].
MATSUYAMA, H ;
OKAMOTO, T ;
TERAMOTO, M .
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1989, 22 (05) :460-468
[8]   EXTRACTION MECHANISM OF RARE-EARTH-METALS IN THE PRESENCE OF DIETHYLENETRIAMINEPENTAACETIC ACID IN AQUEOUS PHASE [J].
MATSUYAMA, H ;
OKAMOTO, T ;
MIYAKE, Y ;
TERAMOTO, M .
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1989, 22 (06) :627-635
[9]   SELECTIVE SEPARATION OF YTTRIUM IONS FROM OTHER RARE-EARTH IONS USING NONEQUILIBRIUM EXTRACTION [J].
MINAGAWA, Y ;
YAJIMA, F .
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 1992, 65 (01) :29-33
[10]  
MINAGAWA Y, 1977, Patent No. 52150717