DIBK-TBP体系萃取分离锆铪(英文)

采用 DIBK 和 TBP 混合萃取剂在硫氰酸盐介质中对锆铪进行萃取分离,考察 TBP 的加入量、水相酸度、料液中锆铪浓度、盐析剂加入量、萃取温度和萃取时间等因素对锆铪分离的影响。结果表明:DIBK-TBP 体系优先萃取铪;在优化工艺条件下,即 20%的 TBP、水相酸度 3.0 mol/L、硫酸铵加入量 0.8～1.25 mol/L、室温、萃取时间 10 min,锆铪的分离系数可达到 9.3。     

锆铪分离的湿法工艺比较及分析

介绍了N235／P2O4—硫酸体系、MIBK—硫氰酸体系和TBP—盐酸硝酸体系分离锆、铪的工艺流程，分别从有机相、料液、萃取洗涤工艺参数、流程工序以及各流程特点对3种分离工艺的优缺点进行了比较。     

锆及锆合金中铪的发射光谱测定

文中用正交实验法就光谱缓冲剂、电极、电流等因素对锆中铪谱线强度影响作了系统实验。证明以上因素对铪谱线增强作用不明显。找到了用一套标准同时测锆及锆合金中铪的合适条件。定量范围3×10~(-3)～1×10~(-1)％。     

用甲基异丁基酮萃取分离锆铪的工艺评价

简要评述了用甲基异丁基酮（MIBK）萃取分离锆铪方法的基本原理、分离工艺和条件、萃取设备。指出，MIBK在硫氰酸体系中萃取分离锆铪分离效果好，技术成熟，可进行规模生产。MIBK法的主要缺点是必须用有毒的SCN作稀释剂，工艺复杂而冗长，操作不易控制，劳动强度大，收率低。MIBK在水中有较大的溶解度，废液不易处理，给工艺操作和环境带来极大困难。     

锆铪分离工艺的发展及现状

介绍了国内外锆铪分离工艺的发展;分析了国外锆铪分离工艺的研究主要是改进正在实施的锆铪分离工艺的环境污染问题;指出改进锆铪冶炼工艺,降低原材料消耗和成本,提高锆铪回收率是我国锆铪生产研究的主要方向。     

用TBP萃取分离锆和铪的工艺研究

研究了以碱熔-盐酸法代替碳氯法制备氧氯化锆溶液，用TBP(磷酸三丁酯)萃取分离锆、铪的工艺。研究结果表明：碱熔-盐酸法制备氧氯化锆，通过提纯可以获得低硅的氧氯化锆溶液，用TBP萃取不产生乳化，两相分离清楚。经小试、中试和扩大连续运转试验，证实了分离效果好、萃取过程不产生乳化、工艺操作稳定、回收率高，可获得原子能级的氧化锆和氧化铪。用TBP萃取分离锆和铪可应用于工业生产。     

Equilibrium and kinetic data of adsorption and separation for zirconium and hafnium onto MIBK extraction resin

The equilibrium and kinetics of methyl isobutyl ketone (MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity, initial total concentrations of zirconium and hafnium and temperature. The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm, and the Freundlich isotherm constants (K_F) are 3.53 and 0.64 mg/g, respectively. The equilibrium data of zirconium also fit the Langmuir adsorption isotherm, and the saturation adsorption capacity (Q_max) and the Langmuir isotherm constant (K_L) are 75.93 mg/g and ?0.012 7 L/g, respectively. The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model, and the rate constants of pseudo-second-order equation (k₂) are ?0.019 and 0.41 g/(mg·min), respectively. Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.     

含锆铝合金的力学性能和强化机理

研究了高强铝合金的力学性能与Zr含量的关系，计算了合金的各种强化因素值。研究发现：合金的抗拉强度巩和屈服强度如σ0.2均随Zr含量的增加而增大，增幅分别达到11．8％和12．6％；合金延伸率δ在Zr添加量不高时随Zr含量的增加而增大，在Zr含量为0．06％时出现峰值，随后合金延伸率δ逐渐稳定在8％左右。结合合金显微特征，合金强化机理主要包括晶粒细化、颗粒弥散强化及形变强化，在Zr含量为0．16％的合金中相应的强化值分别为21.35和14MPa.     

MIBK双溶剂萃取法制备原子能级氧化锆和氧化铪的工艺设计

介绍了国内外制备原子能级氧化锆、氧化铪工艺的研究现状，并对各种工艺流程的优劣进行了技术经济分析。江西晶安高科在我国率先完成了规模为30以的原子能级氧化锆、氧化铪分离工艺中试。其采用MIBK＋有机试剂L双溶剂萃取法分离锆铪，得到的氧化锆中氧化铪含量小于0．006％，氧化铪纯度大于98％。     

碱熔法氯化法制备氯氧化锆的技术经济比较

由于我国核电工业的发展对金属锆、铪的需求将大幅增加,根据国家规划,至2020年我国将再建30座核电站,届时核电装机容量将由目前的57×105kW增到约34×106kW。核级海绵锆、海绵铪的用量将达到103t。以国内公司的生产运行指标为例,比较了碱熔法、碳化氯化法和沸腾氯化法3种制备氯锆方法的技术经济指标。比较结果表明,3种方法中沸腾氯化法成本最低,其单耗成本依次为沸腾氯化法为8345元,碱熔法为9117元,碳化氯化法为12505元。     

Hf和Zr含量对FGH96合金平衡相及PPB的影响

采用材料热力学计算软件Thermo-calc,计算了FGH96合金中的平衡相,并结合显微组织观察、能谱和相分析,探讨Hf、Zr含量对γ’相和碳化物的影响,及对消除PPB的作用。结果表明:Hf和Zr不会导致产生新相,主要影响MC和γ’相的析出行为与成分。Hf和Zr能显著改变MC型碳化物的组分,增加其热力学稳定性和数量,促进MC型碳化物在合金中的均匀分布,抑制MC向M23C6转变;Hf还可以参与形成γ’相,增加其数量。Hf、Zr有助于消除FGH96合金中的原始颗粒边界(PPB)。     

Optimization of parameters,characterization and thermal property analysis of hafnium ethoxide synthesized by electrochemical method

Hafnium ethoxide was synthesized using electrochemical method. Optimization experiments were used to optimize various parameters namely Et₄NBr concentration(c): 0.01–0.06 mol/L, solution temperature (t): 30–78 °C, polar distance (D): 2.0–4.0 cm and current density (J): 100–400 A/m². The electrolytic products obtained under optimum conditions of c=0.04 mol/L, t=78 °C, D=2.0 cm and J=100 A/m² were further isolated by vacuum distillation under 5 kPa. The product was characterized by Fourier transform infrared (FT-IR) spectra, nuclear magnetic resonance (NMR) spectra. The results indicated that the product was hafnium ethoxide. ICP analysis suggested that the content of hafnium ethoxide in the final product exceeded 99.997%. Thermal properties of the product were analyzed by TG/DTG. The vaporization enthalpy of hafnium ethoxide was found to be 79.1 kJ/mol. The result confirmed that hafnium ethoxide was suitable for the preparation of hafnium oxide by atomic layer deposition.     

Corrosion behavior of hafnium in anhydrous isopropanol and acetonitrile solutions containing bromide ions

The corrosion behaviors of hafnium in Et₄NBr isopropanol and acetonitrile(ACN) solutions were investigated using electrochemical measurements, ICP-AES and SEM techniques. Results revealed that the open circuit potential gets more positive due to the increased passivity of the surface oxide film with increasing immersion time until it reaches a steady state value. The potentiodynamic anodic polarization curves did not exhibit an active dissolution region near corrosion potential due to the presence of an oxide film on the electrode surface, which was followed by pitting corrosion. SEM images confirmed the existence of pits on the electrode surface. Cyclic voltammetry and galvanostatic measurements allowed the pitting potential (?_pit) and the repassivation potential (?_p) to be determined. ?_pit increased with increasing potential scanning rate but decreased with increasing temperature, Br^? concentration and ACN concentration. The impedance spectra showed that the resistances of the solution and charge transfer decreased with the increase of ACN concentration.     

Hydrogen evolution and corrosion behavior of zirconium tubing in sub- and supercritical water

Hydrogen evolution is inevitable during the oxidation of zirconium in high-temperature water. A fraction of this evolved hydrogen diffuses into the cladding material, and the remaining is carried away by the reactor coolant. In this study, hydrogen evolution and corrosion behavior of zirconium-702 in high-temperature water are investigated using a continuous tubular flow-through reactor. The results show that at a constant pressure of 25 MPa, the evolution of hydrogen gas from an oxidized zirconium reactor surface is approximately 24 times larger at 500°C than at 350°C. At higher temperatures, the zirconium reactor tubing exposed to water shows ballooning, with bending before the rupture near the exit end of the reactor tube, where the concentration of evolved hydrogen is the highest.