HNO3氧化去除铀反萃液中的C2O^2—4

研究了用ＨＮＯ３氧化去除ＴＲＰＯ流程铀的（ＮＨ４）２ＣＯ３反萃液中Ｃ２Ｏ＾２－４的条件。将含铀的（ＮＨ４）２ＣＯ３反萃液调节成０．２￣０．８ｍｏｌ．Ｌ＾－１Ｈ２Ｃ２Ｏ４－７．５￣９．５ｍｏｌ．Ｌ＾－１ＨＮＯ３溶液,在１００℃下蒸馏回流７ｈ,其中的Ｃ２Ｏ＾２－４被完全分解去除,得到ＵＯ２（ＮＯ３）２－ＮＨ４ＮＯ３溶液。蒸馏回流过程中,ＮＨ４ＮＯ３部分分解,在该条件下操作是安全的。     

HNO3氧化去除铀反萃液中的C2O42-

研究了用HNO3氧化去除TRPO流程铀的 (NH4 ) 2 CO3反萃液中C2 O4 2 - 的条件。将含铀的(NH4 ) 2 CO3反萃液调节成 0 2～ 0 8mol·L- 1H2 C2 O4 7.5～ 9.5mol·L- 1HNO3溶液 ,在 10 0℃下蒸馏回流 7h ,其中的C2 O4 2 - 被完全分解去除 ,得到UO2 (NO3) 2 NH4 NO3 溶液。蒸馏回流过程中 ,NH4 NO3部分分解 ,在该条件下操作是安全的。     

HNO3氧化去除Np-Pu反萃液中的H2C2O4

研究了用HNO3 氧化去除TRPO流程反萃Np Pu的H2 C2 O4反萃液中H2 C2 O4的条件。 7 5mol·L-1HNO3 0 .3mol·L-1H2 C2 O4混合液于 90℃下蒸发 1 3 0h和 1 0 0℃下蒸馏回流 6h ,H2 C2 O4可完全分解去除 ;混合液中添加适量催化剂MnCO3 ,于 1 0 0℃下蒸发或蒸馏回流 ,H2 C2 O4分解加速 ,1～ 1 5h内H2 C2 O4完全分解。蒸发或蒸馏回流过程中产生的HNO2 把Np(Ⅳ )氧化为Np(Ⅴ )和Np(Ⅵ ) ,95 %以上的Pu保持Pu(Ⅳ )。     

HNO3-H2C2O4体系中Np和Pu的分离研究

研究了30％TBP-煤油在不同的硝酸-草酸混合溶液中对Np,Pu各价态的萃取分配,在HNO     

TRPO中Am3+,Pu(Ⅳ),UO2+2,TcO-4的反萃及其红外光谱和裂解色谱分析

研究了硝酸、草酸、碳酸钠和碳酸铵对4种不同来源的TRPO/煤油中Am^3 ,Pu(Ⅳ),UO2^2 和TcO4^-的反萃,观察了碳酸钠溶液反萃铀时的乳化现象,比较了上述4种TRPO的红外光谱、裂解色谱。结果表明,不同来源的TRPO具有相似的基团,但组成有差别。     

TBP—TRPO／煤油萃取HNO3,UO^2＋2,Pu（Ⅳ）,Am^3＋,TcO4^—和Cs …

研究了磷酸三丁酯（ＴＢＰ）－三烷基氧膦／煤油对ＨＮＯ３、ＵＯ＾２＋２、Ｐｕ（Ⅳ）、Ａｍ＾３＋、ＴｃＯ４＾－和Ｃｓ＾＋的萃取;探讨了该体系对ＵＯ＾２＋２和硝酸的负载容量,分析了该体系对Ａｍ＾３＋和ＴｃＯ４＾－的协萃现象,并进行了草酸反萃体系中Ｐｕ（Ⅳ）的研究。     

正丁醛作还原剂时用TBP/煤油萃取分离铀、钚和镎的研究Ⅰ.正丁醛反萃TBP/煤油中的Np

为了解正丁醛在还原反萃分离铀、钚、镎过程中的作用,以正丁醛为还原剂,进行了硝酸水溶液反萃含U(Ⅵ)、Np(Ⅵ)或U(Ⅵ)、Np(Ⅵ)、Pu(Ⅳ)的TBP/煤油中Np的实验研究,测定了串级实验时Np在各萃取器中的分布,讨论了正丁醛、镎、铀、硝酸浓度、相比等对镎在萃取器中分布的影响.单级实验结果表明,正丁醛的加入和延长正丁醛与镎的相互作用时间,有利于从有机相中反萃镎;正丁醛的加入对铀、钚分配比的影响不大;但铀浓度增加会增加镎的反萃.串级实验结果表明,镎在1BP中的比例小于10%;第二级加入正丁醛时,正丁醛和镎在各级的分布较合理,能兼顾镎的去污与反萃.为了减少铀的损失,需要采用较高的硝酸浓度;在1BW中出现少量白色沉淀.     

利凡诺法测定HNO3—H2C2O4混合液中的NO∧—2

用利凡诺（Rivanol）法研究并测定HNO3氧去除了TRPO流程Np、Pu反萃液中H2C2O4时产生的NO∧-2。实验在0.48mol/L HCl介质中,利用Rivanol溶液与NO∧-2生成樱红色配合物性质,用分光光度法测定,结果表明,质量比R（NO∧-3/NO∧-2）≤3.6×10∧4和R（C2O∧2-4/NO∧-2)≤4×10∧3时,均对NO∧-2的测定无影响,方法对NO∧-2的检测下限为0.02mg/L,相对标准偏差为3%,重加回收率为97%～105%。     

HNO3洗涤法去除TRPO相中的H2C2O4

研究了ＨＮＯ３洗涤法去除ＴＲＰＯ相中Ｈ２Ｃ２Ｏ４的条件。结果表明,用５．５ｍｏｌ／Ｌ ＨＮＯ３２级洗涤ＴＲＰＯ流程中Ｈ２Ｃ２Ｏ４反萃Ｎｐ、Ｐｕ段的ＴＲＰＯ相,可以完全去除Ｈ２Ｃ２Ｏ４,ＴＲＰＯ相不再出现混浊。再用（ＮＨ４）２ＣＯ３溶液从ＴＲＰＯ相中反萃Ｕ（Ⅵ）,水相不再产生白色沉淀。确保ＴＲＰＯ提取锕系元素的萃取流程正常进行。     

HEDPA反萃TRPO/煤油和TRPO-TBP/煤油中UO22+、Pu(Ⅳ)、Am3+和TcO4-

研究了用两种不同来源的2-羟乙基-1,1-二膦酸(HEDPA)配制的不同硝酸浓度、不同HEDPA浓度的溶液对30 %TRPO(混合三烷基氧膦)/煤油和20 %TRPO-20 %TBP(磷酸三丁酯)/煤油中UO22+、Pu(Ⅳ)、Am3+和TcO4-的反萃.提出了用HEDPA为反萃剂的TRPO流程.     

Enthalpy measurements of La2Te3O9 and La2Te4O11

Enthalpy increment measurements on La₂Te₃O₉(s) and La₂Te₄O₁₁(s) were carried out using a Calvet micro-calorimeter. The enthalpy values were analyzed using the non-linear curve fitting method. The dependence of enthalpy increments with temperature was given as: H°(T) − H°(298.15 K) (J mol⁻¹) = 360.70T + 0.00409T² + 133.568 × 10⁵/T − 149 923 (373 ? T (K) ? 936) for La₂Te₃O₉ and H°(T) − H°(298.15 K) (J mol⁻¹) = 331.927T + 0.0549T² + 29.3623 × 10⁵/T − 114 587 (373 ? T (K) ? 936) for La₂Te₄O₁₁.     

The crystal structure of Th3B2C3

The crystal structure of Th₃B₂C₃ has been determined by single crystal X-ray analysis. The lattice parameters of the monoclinic cell (first setting) are: $\text{a = 3.703 (2)}\text{A}\text{?}\text{, b = 9.146 (4)}\text{A}\text{?}\text{, c = 3.773 (1)}\text{A}\text{?}\text{and γ = 100.06 (7)°}$; space group: P2/m (C$\text{1}\text{2}{}_{\mathrm{h}}$), Z = 1. Intensity measurements were obtained from a fourcircle diffractometer. The structure was solved by Patterson methods and refined by full matrix least squares calculation. For an asymmetric set of 401 independent reflexions the final R-value is 0.079. The structure contains octahedra, tetrahedra and trigonal prisms of Th-atoms. The trigonal prisms are centered by boron atoms, Th-octahedra by carbon atoms Cl; Carbon atoms C2 actually have octahedral coordination 5 Th + 1 B. The structural chemistry of Th₃B₂C₃ with respect to the crystal structures of ThC and ThBC is discussed.     

Reactivity of hydrogen peroxide towards Fe3O4, Fe2CoO4 and Fe2NiO4

The kinetics of CRUD oxidation by H₂O₂ has been studied using aqueous suspensions of metal oxide powder. Fe₃O₄, Fe₂CoO₄ and Fe₂NiO₄ were used as model compounds for CRUD. In addition, the activation energies for the reaction between H₂O₂ and the three CRUD models were determined. The rate constants at room temperature were determined to 6.6 (±0.4) × 10⁻⁹, 3.4 (±0.4) × 10⁻⁸ and 1.6 × 10⁻¹⁰ m min⁻¹ for Fe₃O₄, Fe₂CoO₄ and Fe₂NiO₄, respectively. The corresponding activation energies are 52 ± 4, 44 ± 5 and 57 ± 7 kJ mol⁻¹, respectively. The mechanism of the reaction is briefly discussed indicating that the final solid product in all three cases is Fe₂O₃. In addition to the experimental studies, the theoretical grounds for kinetics of reactions in particle suspensions are discussed. The theoretical discussion is also used to explain the somewhat unexpected trends in reactivity observed experimentally.     

HfO2 and Ta2O5 as grain growth inhibitors in Eu2O3

Because of the high neutron capture cross section for five consecutive europium isotopes, Eu₂O₃ is of interest as a control material for nuclear reactors. A tendency toward excessive grain growth degrades its mechanical properties. Small amounts of HfO₂ and Ta₂O₅ were added to the Eu₂O₃ in attempts to suppress this grain growth. Three at % substitution of Hf for     

Carbon deposition from a γ-irradiated CO2/CO/CH4/C2H6 gas mixture on the manganese oxides MnO, Mn3O4 and Mn2O3

The composition of oxides formed on steel surfaces within power reactors may influence heat transfer efficiency. Previous studies have indicated that carbon is deposited on spinal-type oxides containing manganese, iron, cobalt, nickel and chromium. In this investigation, characterised manganese oxides have been subjected to γ-irradiation under conditions similar to those experienced in reactors in an effort to understand the catalytic processes involved in deposit initiation and growth. Mn₃O₄ and Mn₂O₃, under the conditions present in the γ-cell, were reduced to MnO during the time of exposure. Relative carbon deposition rates were observed to follow the trend MnO>Mn₃O₄≈Mn₂O₃.     

An experimental study on linear differential scattering coefficients of the radioactive compounds UO2(C2H3O2)2 · 2H2O and Th(NO3)4 · 5H2O at 60 keV

The linear differential scattering coefficients at 60 keV have been measured for UO₂(C₂H₃O₂)₂ · 2H₂O (uranyl-acetate) and Th(NO₃)₄ · 5H₂O (thorium-nitrate) radioactive compounds at seven angles ranging from 60° to 120° at intervals 10°. The obtained results have been compared with relativistic and non-relativistic theoretical values.     

Reduction of UO2 by H2

The reactivity of H₂ towards UO₂²⁺ has been studied experimentally using a PEEK coated autoclave where the UO₂²⁺ concentration in aqueous solution containing 2 mM carbonate was measured as a function of time at p_H2∼40 bar. The experiments were performed in the temperature interval 74-100 °C. In addition, the suggested catalytic activity of UO₂ on the reduction of UO₂²⁺ by H₂ was investigated. The results clearly show that H₂ is capable of reducing UO₂²⁺ to UO₂ without the presence of a catalyst. The reaction is of first order with respect to UO₂²⁺. The activation energy for the process is 130 ± 24 kJ mol⁻¹ and the rate constant is k_298K=3.6×10⁻⁹ l mol⁻¹ s⁻¹. The activation enthalpy and entropy for the process was determined to 126 kJ mol⁻¹ and 16.5 J mol⁻¹ K⁻¹, respectively. Traces of oxygen were shown to inhibit the reduction process. Hence, the suggested catalytic activity of freshly precipitated UO₂ on the reduction of UO₂²⁺ by H₂ could not be confirmed.     

Thermoelectric power studies of ferromagnet U2ScB6C3

The thermoelectric power (TEP) of a ferromagnet U₂ScB₆C₃ (T_C = 61 K) has been measured in the temperature range 5-300 K. The TEP is positive over the whole measured temperature range and reaches a relatively large value at room temperature of 29 μV/K. Below 30 K and above 200 K the TEP follows a straight line S(T) ∼AT, with slope of 0.23 and 0.085 μV/K², respectively. The change in the slope can be explained by the electron-phonon interaction renormalization effects or spin-reorientation associated with a change in the electronic structure. Analysing the temperature dependence of the ratio [S(T)/T]/[S_300 K/300] and taking into account the specific heat data, we suggest that spin fluctuations are another important factor in determining the thermoelectric power behaviour of U₂ScB₆C₃.