铀钼矿石及碳酸盐型铀矿石标准物质研制

根据我国铀矿石的特点及相关元素的实际含量,研制了5个水平的标准物质用于加强铀矿科研和矿山生产的质量管理,监控分析检测工作质量,其中3个为以铀钼矿石为基体的铀钼矿石标准物质,2个为碳酸盐型铀矿石标准物质。并将铀钼矿石标准物质中的铀、钼、铁、硅（二氧化硅）、磷、氟、钒、砷、碳、硫,及碳酸盐型铀矿石标准物质中的铀、钙、镁、铝、硅（二氧化硅）、磷、钒、有机碳、无机碳等元素进行定值。分别采用F检验法和t检验法评价了标准物质的均匀性和稳定性。结果显示,所制得的标准物质的均匀性和稳定性均符合要求。各元素的定值采用多家实验室比对定值,定值数据均满足“一级标准物质技术规范”数据统计要求。     

岩石、矿石及矿物中微量铌、钽的测定方法

铌、钽的分离和测定是分析化学中的难题之一,至今尚未得到彻底解决。尤其是有些矿区的岩石和矿石,其矿物组合复杂,干扰铌、钽测定的元素种类较多,而且铌、钽比值相差又很悬殊,从而对微量铌、钽的测定更增加了困难。本文针对某些矿区的几类岩石、矿石中微量铌、钽的测定问题,在原有方法的基础上进行了一些试验,根据初步实验结果,提出如下的分析方案,以供进一步工作时参考。     

铀矿石浓缩物中砷、铅、镉、汞的分析

正随着我国核电事业的发展,对铀的需求日益增加。铀矿石是提取铀产品的重要原料,铀矿石浓缩物中杂质元素的分析对产品质量控制具有重要意义。本工作采用光谱/质谱法分析了两个铀矿石浓缩物样品中汞、砷、镉、铅的含量。铀中杂质元素的分析技术较为成熟,已有多篇文献报道,国标及行标中也规定了部分铀产品中杂质的分析方法。但采用光谱/质谱法测定铀矿石浓缩物中砷、汞含量的研究尚未见文献报道。     

用螢光伦琴光谱法测定金属量测量样品中的铀

为发现各种元素的异常值,常采用半定量光谱分析方法。这种方法的特点是:快速、经济、灵敏度高和所用样品称量少。该方法的灵敏阈对大多数元素来说均低于其最低异常值,因此用此分析方法可以发现这些元素的异常值。但是半定量光谱分析不能测定铀的异常值,因为该方法的灵敏阈为0.01％铀,而对大多数类型的岩石来说铀的克拉克值较该值低二个数量级。所以通常都采用放射性测量(α或β)法或萤光法测定金属量测量样品中的铀。α辐射测量结果与样品中钾的存在和人工放射     

二氧化铀中氧/铀比的示波极谱测定

本文拟定了用示波极谱仪测定二氧化铀中氧/铀比的方法。采用1.4M H_3PO_4 1.6MH_2SO_4为底液,测定范围溶解后立刻测定为10—100微克/毫升及氧化后总铀测定为600—1200微克/毫升。样品用磷酸溶解,以硫酸稀释防止产生磷酸铀(Ⅳ)胶状沉淀;取出一份溶液直接极谱测定铀(Ⅵ),再取出另一份溶液用高锰酸钾将四价铀氧化成六价,用亚硫酸钠破坏过量的高锰酸钾,测定总铀量,以差减法求出铀(Ⅳ),实验的结果与库博塔(H.Kubota)计算法和伯德(R.M.Burd)图解法一致。方法的精密度为±2%,微量的铁(Ⅲ)、镍(Ⅱ)、硼(Ⅳ)、硅(Ⅳ)、铜(Ⅱ)、铝(Ⅲ)、钨(Ⅵ)、锰(Ⅱ)、钼(Ⅵ)、钒(Ⅴ)等杂质元素对铀的测定无影响,方法简便、快速,不需分离,适宜于工厂例行分析。     

分光光度法测定模拟高放废液中的磷含量

建立了模拟高放废液中磷含量的分析方法。该法是在铋盐存在下,溶液中的正磷酸与钼酸铵形成磷钼黄(磷钼杂多酸),磷钼黄经抗坏血酸还原后形成磷钼蓝,于分光光度计上测量吸光度从而获得样品中的磷含量。开展了磷钼蓝吸收波长、形成酸度、显色试剂用量、稳定时间、干扰离子、重加回收率、精密度等实验。结果表明:在0.8mol/L硝酸溶液中,依次加入硝酸铋、钼酸铵、抗坏血酸能使磷完全形成磷钼蓝,在室温下、40min内磷显色稳定,于分光光度计695nm处有最大吸收,同时硅(0.3mg/L)、铁(4.0mg/L)、镍(2.9mg/L)、铀(0.8mg/L)、铈(0.8mg/L)、镁(0.4mg/L)、锰(1.0mg/L)、铝(2.0mg/L)、铜(1.6mg/L)、铌(0.2mg/L)、锶(0.4mg/L)不影响磷含量(0.2mg/L)的测定。采用该法测定模拟高放废液中磷的含量,重加回收率为99.80%~103.34%,测量的相对标准偏差优于3.0%(n=6),满足分析要求,可用于真实高放废液中磷含量的测量。     

六种常见中药材钾、硫、铬、锰、钒、锆元素含量的研究

采用自主搭建的X射线荧光分析及商用的电感耦合等离子发射光谱方法,对几种常见的植物类(胎菊、北板蓝根)、动物类(蝉蜕、地龙)和中成药类(郁金银翘片、葶贝胶囊)药材样品中典型元素硫、钾、铬、锰、钒、锆的含量进行了分析研究,该套X射线荧光分析(X-ray Fluorescence,XRF)系统对于Cr、Mn元素的检出限较好。分析结果发现在多数药材样品中有较高含量的钾元素,而过量高钾的摄入会对人体心脏和肾脏造成负担,因此根据标准给出每日摄入量小于100 g?d~(-1)的参考值。同样在多数样品中检测到较高含量的硫元素,推测可能是制药工艺中的化学添加物富集所致,需引起关注并值得进一步研究。所有样品中均检测出较低含量的钒、锆元素,说明该中药材样品中不存在显著的钒、锆元素污染。在某些动物类和中成药类药材样品中,检测到超标存在的铬、锰元素,在非必要时需要减少用量。根据铬元素生素矿物质可耐受最高每日摄入量小于0.5 mg?d~(-1)的标准,给出了这几种药材样品的建议每日最大摄入量:植物类样品小于2.841 g?d~(-1)、动物类样品小于0.958 g?d~(-1)、中成药类样品小于0.935 g?d~(-1)。     

某火山热液铀矿床的铀矿石、沥青铀矿电渗析和浸出实验

一、引言某地火山热液铀矿床矿石中铀、钼元素的存在状态,经过研究虽获得了一些结果,尤其是对铀的赋存状态有了比较成熟的意见,但是对钼的赋存状态,尚未完全解决。为此,我们基于野外及室内工作,初步尝试利用电渗析法并配合浸出实验,来研究铀矿石中铀、钼元素的赋存     

铀裂变产物中放射性Nb~(95)的测定

本文研究并制定了在热铀溶液中分离测定Nb~(95)的方法。此方法是在格伦迪宁水解法测定铌的基础上加以改进而制定的。改进了做源的沉淀形式,以8-羟基喹啉铌的沉淀形式做源、称重、测量放射性强度。该法操作简单,适用于冷却了45天后热铀溶液中Nb~(95)的分离及测定。产额在75—90%的范围内。γ放射性测量的精密度以单值的相对标准偏差表示为1.5%,对单个元素的去污因数大于10~3,平行操作四个样品可以在4—5个小时内完成。     

ICP-MS法测定铀化合物中的5个杂质元素

建立了电感耦合等离子体质谱法(ICP-MS)测定铀化合物中的锰、镍、铜、铝和镁等5个杂质元素的方法。将样品和铀化合物标准物质消解后,通过配置一系列不同铀含量的工作曲线,将标准溶液和样品中铀含量控制在相同水平,采用基体匹配法测量各杂质元素的含量。该方法的检出限为0.008 ng·mL~(-1)～0.038 ng·mL~(-1)。通过实验可知溶液中铀浓度控制在100μg·mL~(-1)以下时,铀标准物质可以得到准确的结果。通过此方法测量了比对样品中锰、镍、铜、铝和镁的结果,含量范围为2.11μg·g~(-1)～84μg·g~(-1)U。     

Sorption-Extraction Processes in Uranium Hydrometallurgy: Coextraction of Valuable Components and Dual-Purpose Technology

Sorption-extraction processes for obtaining finished coproducts during processing of uranium ores with valuable components, such as Mo, V, W, Re, Au, Sc, rare-earth elements, Y, Cs, Cu, Ta, Nb, Zr, Hf, Mn, Sn, and Se, are described. Special attention is focused on experience in extraction decontamination of phosphoric acid with its uranium and thorium content decreased by a factor of 20 and obtaining from it ecologically pure phosphate fertilizers and feed phosphates.Data are generalized for three variants of profitable coproduction of the final products: sorption and desorption of valuable components together with uranium and separation of the extracted components at the extraction refining stage; sorption of variable components together with uranium and separation of the components at the desorption stage; separate sorption extraction of uranium and valuable components on selective and highly concentrating ionites. 1 figure.     

Radiation-induced segregation in titanium alloys

Radiation-induced segregation (RIS) of V, Mo, Nb, Ta, Zr, and Sn in binary titanium alloys was investigated to test the solute size effect correlation in hcp alloys. Undersize Mo segregates weakly toward the sinks. Nb and Ta, which are slightly oversize in Ti, undergo little or no RIS. Oversize Zr solute in Ti segregates away from the sinks, whereas undersize Ti solute in Zr is enriched at sinks. All of these results are in accord with the solute size effect correlation. Surprisingly, Sn, which is significantly oversize in Ti, appears to segregate very little. The postirradiation annealing of Ti-3V and Ti-8Al-1V-1Mo confirmed that segregation of undersize V toward sinks is radiation-induced. Measurements of temperature and dose dependence in binary and complex alloys showed that the degree of V segregation has a maximum at ~ 600 °C and obeys parabolic growth kinetics in its early stages but probably saturates at a rather low dose ( ~ 0.8 dpa).     

The use and performance of graphite and metal ISSECs in tokamak fusion reactors

Carbon and the metallic elements molybdenum, niobium, vanadium and tungsten have been considered for use as an ISSEC (Internal Spectral Shifter and Energy Converter) in tokamak fusion reactors. All five materials have been shown to reduce the radiation damage in the 316 SS structural first wall and thus increase the first wall lifetime. On a per unit thickness basis, a tungsten ISSEC is most effective in this regard followed by Mo, Nb, V and carbon ISSECs in decreasing order. If the ISSEC is restricted to transfer its heat to the first structural wall by thermal radiation only, the maximum allowable thickness a carbon ISSEC can have is limited to 9.5 cm, Mo ISSEC to 7.5 cm, Nb to 8.5 cm, V to 4.5 cm and a W ISSEC to 6 cm for a 1 MW/m² neutronic and 4 W/cm² surface heat loading. If the ISSEC is cooled by radiation plus conduction, the maximum allowable thickness goes up to 13 cm for C, 10 cm for Mo, 8 cm for V and stays the same for Nb and W. The only ISSEC material to result in an overall reduction in total blanket radioactivity at shutdown is carbon while all of the metallic ISSECs increase the total activity. On the other hand, the long term activity (at 1000 years after shutdown) is increased for Mo, Nb and V ISSECs while it is reduced by C and W. The carbon and V ISSECs reduce the energy production per fusion while Nb and W increase it slightly and Mo results in a 15–17% energy production increase. On a relative cost basis, metallic ISSECs cost 30–55 times more than a carbon ISSEC when used at the maximum thicknesses given above. Among the four metals studied, Mo is considered to be the best material for use as an ISSEC. A definitive choice between a graphite and Mo ISSEC is difficult at this time as both materials have strong positive features; carbon being superior from radioactivity, afterheat, cost and fabricability standpoint, but molybdenum being more effective in reducing the radiation damage in the first structural wall and increasing the energy multiplication in the blanket.     

K-shell X-ray fluorescence cross-sections and intensity ratios for some pure metals at 59.5 and 123.6 keV

K-shell X-ray fluorescence cross-sections for some pure metals such as Cr, Fe, Co, Cu, Zn, Ga, Se, Y, Mo, Cd, In, Sn, Te, Ba, Ta, W and Bi have been theoretically and experimentally determined. The Cr, Fe, Co, Cu, Zn, Ga, Se, Y, Mo, Cd, In, Sn, Te and Ba metals were excited by 59.5 keV γ-ray from 50 mCi ²⁴¹Am radioactive source and the Ta, W and Bi targets were excited by 123.6 keV γ-ray from 25 mCi ⁵⁷Co radioactive source. The characteristic K X-rays emitted by samples were detected by using a super Si(Li) detector having a resolution of 150 eV at 5.9 keV. In addition, the I_Kβ/I_Kα intensity ratios for these metals were studied. The obtained experimental values of the K-shell X-ray fluorescence cross-sections and the I_Kβ/I_Kα intensity ratios have been compared with theoretical values. The measured values were in good agreement with theoretical values.     

类铀矿岩材料制备及氡扩散系数测定的实验研究

扩散过程是主导氡在铀矿岩中运移与析出的主要方式。铀矿原岩辐射较大且取样困难,不利于开展有关室内实验。为了解决以上问题,依据相似理论,以某花岗岩为原型,选取石英砂、铀尾砂、水泥、精铁粉和微硅粉等为原材料,制备了3种不同材料配比的圆柱形类铀矿岩试样,并测定了原型和试样的物理力学参数;然后采用密闭腔体法测量了原型和试样在不同包裹方式下的累积氡浓度,推导氡的扩散性能参数的计算公式,通过计算获得了原型和试样的氡扩散长度和扩散系数。实验结果表明:花岗岩原型与所制备的类铀矿岩的颗粒密度、抗压强度、抗拉强度、内聚力和内摩擦角相似比的均值分别为1.09∶1、3.93∶1、4.28∶1、3.47∶1和1.00∶1;花岗岩原型的扩散系数为0.146×10^-6m²·s^-1,类铀矿岩的扩散系数介于0.114×10^-6～0.594×10^-6m²·s^-1之间,两者的相似比介于0.25∶1～1.28∶1之间。研究认为所制备的试样3在一定程度上可用来模拟花岗岩型铀矿岩,以满足室内实验的需求。     

查干诺尔盆地地下水中铀和伴生元素特征及其研究意义

为了剖析和预测查干诺尔盆地铀成矿的有利地带,运用放射性水文地质研究方法,通过对所采集的53个上升泉地下水化学样品进行铀与硒、钼、铼和钒等元素含量的测定,系统地分析了铀及其伴生元素的含量特征.结果表明,查干诺尔盆地西部地下水中铀与硒、钼、铼和钒含量等值线呈NE向展布,并从NW向SE方向铀含量具有由低到高、再由高到低的变化趋势.通过综合分析地下水样测试数据及其在外生后成砂岩型铀成矿作用方面的成因联系,结合区域地质和水文地质等成矿条件,认为盆地西部构造斜坡区具有良好的铀成矿前景,并圈定出5片成矿远景区:古宁浑迪、冲果勒浑迪、哈沙廷呼都格、安达特浑迪和那尔图远景区.     

热液铀矿(火山岩型)成分分析标准物质的研制

研制了10种热液铀矿(火山岩型)成分标准物质,对每种热液铀矿(火山岩型)标准物质中的U、Th、Mo、Cu、Pb、Zn、Co、Ni、Cr、Na_2O、CaO、FeO、Fe_2O_3、TiO_2、P_2O_5、CO_2、F、S等成分进行了定值,其中U的质量分数为7.33~2 583μg/g。根据国家一级标准物质研制规范(JJG 1006-1994)和ISO导则35的要求,对10种热液铀矿(火山岩型)标准物质候选物进行均匀性和稳定性检验,其结果符合要求;对每种热液铀矿(火山岩型)标准物质候选物采用9个实验室合作定值的方法进行定值,得到定值结果和相应的不确定度。     

Void formation and solute segregation in ion-irradiated niobium-base alloys

The void-volume fraction in unalloyed Nb and Nb-base binary alloys containing either ~ 2.4 a/o Mo, Ti, Zr, Hf, Ni, Fe, V or Ta has been determined from observations of specimens by transmission electron microscopy following 3.0-MeV ⁵⁸Ni⁺ ion irradiation at 1225 K to ~ 50 dpa. Also, the thermal- and irradiation-induced segregation of these substitutional-atom solutes to the specimen surface and within the irradiation-damaged layer have been determined by use of the Auger Electron Spectroscopy technique. In addition, the segregation of the intrinsic, interstitial-O impurity (~ 0.06 a/o) in these irradiated or annealed materials has been determined. The void-volume fraction and the segregation of solutes have been shown to be correlated by the solute diffusivity and the relative chemical affinity of the substitutional solutes for O. The correlated diffusion of vacancy defects and O atoms is postulated to explain the experimental results.     

Deuteron-Induced Cross Section Calculations of Some Structural Fusion Materials

The development of fusion materials for the safety of fusion power systems and understanding nuclear properties is important. The reaction cross-section data have a critical importance on fusion reactors and development for fusion reactor technology. In this study, the theoretical cross sections of some structural fusion materials such as Cr, V, Fe, Ni, Zr and Ta in deuteron-induced reactions have been investigated. The new calculations on the excitation functions of ⁵⁰Cr(d, α)⁴⁸V, ⁵¹V(d, 2n)⁵¹Cr, ⁵¹V(d, 4n)⁴⁹Cr, ⁵⁴Fe(d, α)⁵²Mn, ⁵⁴Fe(d, n)⁵⁵Co, ⁵⁸Ni(d, α)⁵⁶Co, ⁹⁶Zr(d, n)⁹⁷Nb, ⁹⁶Zr(d, 2n)⁹⁶Nb and ¹⁸¹Ta(d, 2n)¹⁸¹W reactions have been carried out up to 90 MeV incident deuteron energies. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the geometry dependent hybrid model and hybrid model. Equilibrium effects have been calculated according to the Weisskopf–Ewing model. The ALICE/ASH computer code has been used in all calculations. The calculated results have been compared with the experimental data existing in EXFOR database and found to be in good agreement.