引用本文:
李德谦, 张杰, 徐敏. 2-乙基己基膦酸单(2-乙基己基)酯(HEH[EHP])萃取稀土元素机理的研究Ⅰ.稀土元素(Ⅲ)在HNO3-H2O-HEH[EHP]体系中的分配及温度和溶剂效应[J]. 应用化学,
1985, 2(2): 17-23.
Citation: Li Deqian, Zhang Jie, Xu Min. STUDIES OF EXTRACTION MECHANISM OF RARE EARTH COMPOUNDS WITH MONO(2-ETHYL HEXYL)2-ETHYL HEXYL PHOSPHONATE(HEH[EHP])Ⅰ.THE DISTRIBUTION OF RARE EARTH COMPOUNDS IN THE SYSTEM HNO3-H2O-HEH[EHP]AND THE EFFECT OF TEMPERATURES AND SOLVENTS[J]. Chinese Journal of Applied Chemistry, 1985, 2(2): 17-23.
Citation: Li Deqian, Zhang Jie, Xu Min. STUDIES OF EXTRACTION MECHANISM OF RARE EARTH COMPOUNDS WITH MONO(2-ETHYL HEXYL)2-ETHYL HEXYL PHOSPHONATE(HEH[EHP])Ⅰ.THE DISTRIBUTION OF RARE EARTH COMPOUNDS IN THE SYSTEM HNO3-H2O-HEH[EHP]AND THE EFFECT OF TEMPERATURES AND SOLVENTS[J]. Chinese Journal of Applied Chemistry, 1985, 2(2): 17-23.
2-乙基己基膦酸单(2-乙基己基)酯(HEH[EHP])萃取稀土元素机理的研究Ⅰ.稀土元素(Ⅲ)在HNO3-H2O-HEH[EHP]体系中的分配及温度和溶剂效应
摘要:
本文研究了HEH[EHP]的正己烷溶液在不同浓度(0-11M)的硝酸介质中萃取稀土元素(Ⅲ)的平衡规律。借助IR、NMR测定和斜率法研究了不同硝酸浓度下的萃取平衡反应,计算了不同萃取机理的浓度平衡常数。研究了温度和溶剂对萃取平衡的影响,测定了不同硝酸浓度和温度下各相邻元素对的分离因数,计算了萃取平衡反应的焓变值△H、相对自由能变化值ΔZz以及相对熵变值ΔSz,并考察了这些热力学函数随原子序数的递变规律。
English
STUDIES OF EXTRACTION MECHANISM OF RARE EARTH COMPOUNDS WITH MONO(2-ETHYL HEXYL)2-ETHYL HEXYL PHOSPHONATE(HEH[EHP])Ⅰ.THE DISTRIBUTION OF RARE EARTH COMPOUNDS IN THE SYSTEM HNO3-H2O-HEH[EHP]AND THE EFFECT OF TEMPERATURES AND SOLVENTS
Abstract:
The extraction behaviour of rare earth elements(Ⅲ) from nitric acid soltition by HEH[EHP]-hexane has been systematically investigated. The mechanism of extraction carried out in different acidities is discussed in terms of slope, IR and NMR data obtained. It is concluded that at low aqueous acidity, rare earths(Ⅲ) are extracted by a cation-exchange reaction with hydrogen liberation: Ln3++3(HL)2(0)
Ln(HL2)3(0)+3H+ (1) and at high aqueous acidity the extraction is accompanied by a solvation reaction similar to that for TBP; Ln3++3NO3-+2(HL)2(o)
Ln(NO3)3·4HL(o) (2) The influences of temperature and solvent upon the extraction equilibrium under different conditions were discussed in detail. The equilibrium constants (K1 anb K2) andthe thermodynamic functions (ΔH, ΔZn and ΔSz)of extraction reaction were calculated.The dependency of K,ΔZz and ΔSz on the atomic number of rare earth elements werealso discussed.
Ln(HL2)3(0)+3H+ (1) and at high aqueous acidity the extraction is accompanied by a solvation reaction similar to that for TBP; Ln3++3NO3-+2(HL)2(o)Ln(NO3)3·4HL(o) (2) The influences of temperature and solvent upon the extraction equilibrium under different conditions were discussed in detail. The equilibrium constants (K1 anb K2) andthe thermodynamic functions (ΔH, ΔZn and ΔSz)of extraction reaction were calculated.The dependency of K,ΔZz and ΔSz on the atomic number of rare earth elements werealso discussed.-
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