γ辐射对30%TRPO-煤油萃取性能及物理参数的影响

测试了γ辐照剂量对国产三烷基氧膦(TRPO)萃取性能、反萃性能(U、Pu、Am、En、Pm)、物性参数(密度、粘度、折光率、紫外透光率)的影响。用红外光谱观察了辐解产物的特征峰,检出了聚合物、烷基膦酶、亚硝基化合物、硝基化合物、羰基化物等辐解产物,用简单的5%Na_2CO_3-1mol/L HNO_3-H_2O洗涤法,可把主要的辐解产物除去。研究结果表明:TRPO具有良好的辐照稳定性,可以安全地用于处理强放废液和某些超铀靶件。     

γ辐照30%三烷基氧化膦-煤油体系萃取乳化的研究

研究了γ辐射三烷基氧化膦（TRPO）的乳化性能，实验表明，萃取水相酸度的增加，有利于去乳化作用。γ辐射对305TRPO－煤油－硝酸体系的乳化作用有显著影响，不同厂家生产的TRPO具有不同的乳化性能。γ辐照的磷酸三丁酯(TBR)－煤油－硝酸体系较TRPO－煤油－HNO3体系分相和去乳化速度较快。但当用5％Na2CO3溶液洗涤上述两个体系时，TBP－煤油体系有机相去乳化速度较慢，其平衡水相有乳化现象，而TRPO－煤油体系虽分相慢，但分相后有机相的去乳化速度较快，其平衡水相无乳化现象。     

γ辐照对三烷基氧化膦萃取Fe(Ⅲ)的影响

三烷基氧化膦具有优越的锕系元素萃取性能和较高的辐照稳定性。 30 %TRPO -煤油已被用作高放废液 (HAW )处理的萃取剂 ,HAW中常含有大量的Fe(Ⅲ )。研究了辐照 30 %TRPO-煤油溶剂的萃取和反萃取性能。萃取剂吸收剂量为 0 .1× 10 5— 10 .0× 10 5Gy。研究结果表明 ,在吸收剂量 0 .1× 10 5— 1.0× 10 5Gy时γ辐照对萃取分配比没有影响 ,当吸收剂量达到 3.0×10 5Gy时Fe(Ⅲ )的萃取分配比显著增加。试验表明用 0 .6mol/L草酸溶液洗涤辐照有机相可以消除辐照的影响     

γ辐照对TRP0流程萃取体系乳化性能的影响

研究了处理高放废液的TRPO流程的萃取剂TRPO经γ辐照后的乳化情况。提出了在所研究的体系中对乳化程度的衡量方法。研究了平衡水相PH值和吸收剂量对萃取体系乳化的影响,结果表明：乳化与水相PH密切相关,且随着有机相吸收剂量的增加,乳化程度加剧。考察了TRPO辐解产生的辐解产物对乳化的影响,结果表明：TRPO和稀释剂辐照生成的聚合产物是引起乳化的主要原因。体系的乳化可以通过酸化、碱洗或采用离心萃取器等方法减轻甚至消除。     

三烷基氧膦对硝酸介质中钌的萃取行为

研究了三烷基氧膦(TRPO)对硝酸介质中钌的萃取行为。使用TRPO为萃取剂,煤油(OK)为稀释剂,重点考察了萃取平衡时间、水相硝酸浓度、温度、萃取剂浓度、亚硝酸盐浓度等因素对钌的萃取影响,并进行了钌的三级错流萃取实验。另外,还研究了硝酸浓度、温度等因素对钌的反萃过程影响。结果表明,由于钌在水相和有机相中存在着多个种态的平衡和转化过程,热力学和动力学作用相互影响,使得TRPO对钌的萃取行为以及有机相中钌的反萃行为均十分复杂。为进一步了解TRPO对高放废液中钌的萃取行为,进行了TRPO/煤油对不同酸度、浓缩倍数的模拟高放废液中钌的萃取和反萃实验,相关结果为进一步优化TRPO流程工艺提供了重要参考。     

二芳基二硫代膦酸对Am(Ⅲ)和Ln(Ⅲ)的萃取

合成了二苯基二硫代膦酸(DPDTPI)、二氯苯基二硫代膦酸(DCPDTPI)、二甲基苯基二硫代膦酸(DMP-DTPI)、二(2,5-二甲基苯基)二硫代膦酸(DDMPDTPI)和二(3,5-二氯-4-甲基苯基)二硫代膦酸(DDCMPDT-PI)共5种二芳基二硫代膦酸类萃取剂,并研究了它们的二甲苯溶液在HClO4-NaClO4体系中,对Am(Ⅲ)和稀土元素的萃取行为。结果表明,萃取能力按DDCMPDTPI>DMPDTPI>DPDTPI>DCPDTPI>DDMPDTPI的顺序减弱;对镅的萃取选择性由大到小的顺序为:DCPDTPI>DPDTPI>DDMPDTPI>DMPDTPI>DDCMPDTPI,所获得的最大分离因数α(Am/Eu)分别为21,4.4,1.8,1.3和1.0。5种二芳基二硫代膦酸对镧系元素的萃取均为正序萃取。     

γ辐照30%三烷基氧化膦—煤油体系萃取乳化的研究

研究了γ辐射三烷基氧化膦（TRPO）的乳化性能。实验表明，萃取水相酸度的增加，有利于去乳化作用。γ辐射对30?RPO-煤油-硝酸体系的乳化作用有显著影响，不同厂家生产的TRPO具有不同的乳化性能。γ辐照的磷酸三丁酯（TBP）-煤油-硝酸体系较RTPO-煤油-HNO3体系分相和去乳化速度较快。但当用5?a2CO3溶液洗涤上述两个体系时，TBP-煤油体系有机相去乳化速度较慢，其平衡水相有乳化现象，面TRPO-煤油体系虽分相慢，但分相后有机相的去乳化速度较快，其平衡水相无乳化现象。     

用三烷基(C_6-C_8)氧磷(TRPO)从强放废液中萃取锕系、镧系元素的研究

本文研究了三烷基(C_6-C_8)氧膦(TRPO)对锕系、镧系元素及裂变产物的萃取行为;测得了铀、镎、钚、镅、锔等20余种离子在30％TRPO-煤油-硝酸溶液中的分配比以及部分离子的被萃络合物形式;测定了稀释剂、萃取剂浓度、温度、盐析剂等因素对TRPO萃取三价锕系和镧系元素的影响,为用TRPO萃取剂从强放废液中提取有用元素提供了基础数据。     

三烷基(混合)氧膦的结构分析及其对镎、钚的萃取

本文用红外光谱和核磁共振谱研究了TRPO的组成及萃取结构,证明了萃取是由膦酰基上氧原子的孤对电子配位引起的,萃取络合物为配位络合物。研究了 TRPO萃取水和硝酸的平衡常数及络合物结构形式。还用~(238)Np示踪和α液体闪烁测量研究了TRPO-煤油-硝酸体系中各种价态的镎、钚萃取和反萃取情况。     

用三烷基(C_6-C_8)氧膦(TRPO)萃取-液体闪烁计数法测定水溶液中微量α核素的研究

用三烷基氧膦(TRPO)作萃取剂,二甲苯为溶剂,2.5-二苯基噁唑为闪烁体研究了TRPO及杂质元素的猝灭效应,结果表明萃取-液体闪烁计数法用于测量大量杂质元素及氨羧络合剂中的~(233)U,~(239)Pu,~(241)Am微量α核素具有简便、迅速,灵敏高度等优点。     

Evaluation study on properties of a macroporous silica-based CMPO extraction resin to be used forminor actinides separation from high level liquid waste

Basic properties of a silica-based octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) extraction resin (CMPO/SiO2-P) was investigated.Adsorption behavior for some rare earth elements (RE) which are constituents of high level liquid waste (HLLW) and the long-term stability of the extraction resin in nitric acid solution were examined.The CMPO extraction resin was significantly stable in 3 mol·L?1 HNO3 solution at 50oC.Furthermore,the RE(III) were efficiently separated from non-adsorptive fission product (FP) elements such as Sr(II) in a column experiment using a highly nitric acid solution.The separation behaviors of the elements are considered to result from the difference in their adsorption and elution selectivity based on the complex formation with CMPO.There was no strong dependency of RE(III) separation efficiency on feed solution flow rate.Only from the perspectives of the acid-resistant behavior of CMPO extraction resin and the elution kinetics for the metal ions with the extraction resin,the CMPO extraction resin can be used in the modified MAREC process for HLLW partitioning.     

Enhancement of the Mutual Separation of Lanthanide Elements in the Solvent Extraction Based on the CMPO-TBP Mixed Solvent by Using a DTPA-Nitrate Solution

The mutual separation behavior of rare earth elements was studied in the system based on the neutral extractant CMPO (n-octyl(phenyl)-N,N-diisobutylcarbamoyl methylphosphine oxide) and aminopolyacetic acid DTPA (diethylenetriamine pentaacetic acid). The extractability of lanthanides decreased monotonously with increasing of atomic number in the system of 0.2 M CMPO-1.0 M TBP-n-dodecane (TRUEX solvent) and 0.05 M DTPA-NaNCO₃ or hydroxylamine nitrate (HAN) solution. The separation factor of La/Lu was 6,600 using 0.05 M DTPA-3M NaNO₃ solution (initial pH=2.0). The mutual separation of lanthanides in the CMPO/DTPA system was greatly improved when compared with the general TRUEX system. The separation factor was not affected by the initial pH of the solution (1.8–2.2), the salting out reagent (NaNO₃ and HAN), or its concentration (2, 3 M). The experimentally obtained separation factors of lanthanide elements were reproduced by a simple model based on the distribution ratios in the TRUEX extraction system and the stability constants of DTPA-metal complex. The mutual separation between light lanthanides is attributed to the selectivity of DTPA, while CMPO mainly influences the separation of heavy lanthanides.     

从高放废液中提取锕系元素的研究—TRPO萃取体系的改进

观察了用ＴＲＰＯ萃取法直接处理我国生产堆高放废液产生第三相的情况，研究了稀释法和加入添加剂地形成三相及以镅为代表的锕系元素的萃取能力的影响，对ＴＢＰ－ＴＲＰＯ－煤油萃取系进行了辐照稳定性研究。     

Separation of actinoids from HLW by thiacalix[4]arene compound impregnated silica ion-exchanger

If trivalent actinoids such as Am can be separated from high-level radioactive liquid waste (HLLW) generated by the PUREX process, long-term heat and radiation hazards can be significantly reduced in the disposal of this waste. This paper reports the effective separation of Am through the use of a chelating ion-exchange method that uses an octylphenyl-N,N-diisobutylcarbomoyl phosphine oxide (CMPO) or thiacalix[4]arene compound impregnated silica ion-exchanger. The separation of Cs and Sr from HLLW can be achieved using a CMPO impregnated silica ion-exchanger (CMPO-exchanger). Actinoids and lanthanoids can then be eluted from the CMPO-exchanger, with the resulting solution then treated to separate the actinoids using a thiacalix[4]arene compound impregnated silica ion-exchanger. Thiacalix[4]arene compound impregnated silica ion-exchangers have been shown to effectively separate actinoids from lanthanoids in a weak-acid solution. The influence of gamma ray irradiation on adsorption is also investigated. The adsorption of Am remains high even after irradiation of the ion-exchanger.     

A Nuclear Magnetic Resonance Study on Ligand Exchange Reactions in La(III), Nd(III), and U(VI) Nitrato Complexes with n-Octyl(pheny1)-N,N-Diisobutylcarbamoylmethylphosphine Oxide in Non-aqueous Solvents

The exchange reactions of n-octyl(pheny1)-N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in La(III), Nd(III), and U(VI) nitrate complexes with CMPO (La(III)-, Nd(III)-, and U(VI)-CMPO complexes) have been studied in CD₃COCD₃ by means of ³¹P NMR method. The number of CMPO coordinated to the first coordination sphere of La(III) ion was directly determined to be 3 by the area integrations of ³¹P NMR signals of free and coordinated CMPO molecules. The same coordination number of 3 was also obtained for the U(VI)-CMPO complex. The coordination number was not determined for the Nd(III)-CMPO complex, because of its paramagnetic behavior. The exchange rate constants of CMPO in La(III)- and U(VI)- CMPO complexes were obtained by the two-site exchange model. Paramagnetic line broadening was observed in the Nd(III)-CMPO complex and the rate constant for the exchange of CMPO was determined by the line-broadening method. The exchange rates of CMPO in La(III)- and Nd(III)-CMPO complexes depend on the free CMPO concentration ([CMPO]), while that in U(VI)-CMPO complex is independent of [CMPO]. The dissociative (D) and dissociative interchange (I_d ) mechanisms were proposed for the exchange reactions in the La(III)- and Nd(III)-CMPO complexes, and dissociative (D) or I_d mechanism was proposed for the U(VI)-CMPO complex. The dissociative rate constants (s^?1) at 25°C and activation parameters ΔH^# (kJ·mol^?1) and ΔS^# (J·K^?1·mol^?1) are 4.76x10³, 28.7±0.1, ?78.4±0.2 for La(III)-CMPO complex, 4.72x10³, 42.6±0.4, ?31.7±1.3 for Nd(III)-CMPO complex, and 3.20x10³, 46.9±0.6, ?20.5±2.2 for U(VI)-CMPO complex, respectively.     

Structural and Electrochemical Studies on Uranium(VI) Nitrato Complex with n-Octyl(phenyl)-N,N-Diisobutylcarbamoylmethylphosphine Oxide in Non-aqueous Solvents

The structure of uranyl nitrato complex with CMPO [n-Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide] in solid state and in non-aqueous solvents without containing free CR/IPO has been studied by using IR spectrophotometer, ¹³C- and ³¹P-NMR. The carbonyl(vcO) and phosphoryl(vpO) stretching bands of coordinated CMPO were observed at lower wavenumber than the corresponding bands of free CMPO in both the states. The ¹³C and ³¹P peaks assigned to the carbonyl carbon and phosphoryl phosphine of coordinated CMPO was detected in the lower field than that of free CMPO. From these results, it was concluded that the uranyl nitrato complex with CMPO in both the states has the structure with two nitrate and one CMPO coordinated as bidentate in the equatorial plane of uranyl ion, i.e., UO₂(NO₃)₂·CMPO. Furthermore, the electrochemical studies of UO₂(NO₃)₂·CMPO complex in CH₃CN have been carried out using cyclic and normal pulse voltammetric methods. It was found that the UO₂(NO₃)₂·CMPO complex is reduced to U(V) complex at around ?1.22V vs. Fc/Fc⁺ (ferrocene/ferrocenium) and that the resulting reductant is oxidized to U(VI) at around +0.04V vs. Fc/Fc⁺.