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铀矿浓缩物的溯源研究在核法证学中具有重要地位,通过测量其中的铅、锶同位素丰度比能为溯源提供部分地理指示信息。对铀矿浓缩物中铅、锶同位素的精准测量主要受制于大量铀与微量铅、锶的分离、富集。本文利用Eichrom Sr树脂对铅、锶的特效吸附性,通过正交试验对影响铅、锶回收率的主要因素(淋洗酸度、流速、体积)进行了优化,确定了最佳淋洗条件;进而利用UTEVA树脂对铀的特效吸附性,与Eichrom Sr树脂联用,实现了铀矿浓缩物中大量铀与微量铅、锶的分离,有效降低了因铅、锶洗脱液中铀含量过高而引起的基体效应。实验结果表明:铅、锶回收率均 90%,铅、锶洗脱液中的铀含量低于500ng,优于文献报道值(48. 8μg)。利用该方法对实际铀矿浓缩物样品进行测量,分析结果显示铅、锶同位素丰度比可以作为铀矿浓缩物的地理溯源判据,为今后建立铀矿浓缩物中铅、锶同位素数据库提供技术支持。 相似文献
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Sr、Nd、U等同位素体系被广泛应用于地球表生过程中年代测定及物源示踪等研究,高效地分离这些同位素体系,对于推广这些同位素方法的应用具有重要现实意义。若要同时分析地质样品中Sr、Nd、U三种元素的同位素,现有方法往往需要消解两份样品,一份用于Sr-Nd而另一份用于U的分离提纯。这种方法不但增加了样品用量,而且需要多次蒸干溶液转换介质,既延长了分离流程也增加了样品被污染的风险。为了提高样品利用率和分析效率,本文通过将树脂柱串联改进了分离流程,提出一种仅需消解一份样品,便可同时提取Sr、Nd、U三种元素的新方法。本方法中Sr的分离采用Sr特效树脂,包含Nd在内的稀土元素(REE)的分离采用AG50W-X8树脂,U的分离采用UTEVA特效树脂。实验中将三种树脂柱串联,采用3mol/L硝酸淋洗液淋洗,同步进行平衡树脂、上样、洗杂志,避免了蒸干操作。分离后的淋出液使用电感耦合等离子体质谱仪(ICP-MS)测试元素含量。结果表明：U的回收率接近99.9%,Sr的回收率超过90%,Nd的回收率超过80%;同时三种树脂柱串联的分离流程,主要基体元素(K、Ca、Na、Ba、Fe、Rb等)的去除率均超过9... 相似文献
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本文推荐一种用萃取色谱法测定地质样品中的铀和钍的方法。溶样后，用Fe(OH)3沉淀法预富集铀和钍，再用UTEVA树脂分离，使分离的铀和钍电沉积在不锈钢圆盘上，再用α能谱法测定。用晶质铀矿、珊瑚和花岗岩标准物质评价该法。测得的铀和钍含量及^234U/^238U和^230Th/^234U活性比值与标准值十分一致。发现钚的存在会干扰分离，但利用氨基磺酸亚铁还原就可解决此问题。该法的化学回收率与阴离子交换法相近，但萃取色谱法能用较少试剂进行较快分离。 相似文献
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水体的铀同位素比值是反演古海洋及古大气氧化还原变化的有效手段,但是天然水样品中铀元素含量较低,需要对水体进行富集和纯化。文章将水中铀元素不同的富集方法结合UTEVA树脂柱二次分离的回收率进行比较,并对比了其相对于参考值的偏倚程度,使用多接收电感耦合等离子质谱仪(MC-ICP-MS)测定分离纯化后样品的铀同位素比值(235U/238U和234U/238U)。结果表明Ca3(PO4)2共沉淀的富集方式回收率最高(78.5%),且比值偏倚程度较小(235U/238U偏倚值为0.007%,234U/238U偏倚值为0.064%),并可以大幅度降低杂质干扰,适用于水中铀元素的富集。 相似文献
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本文研究了5208萃淋树脂(异烷基膦酸二丁酯)分离富集钍的效果:经柱色层分离后钍能100％回收,并且钍容易洗脱;100毫克铀、50毫克钛、30毫克稀土、20毫克锆及大量的其它杂质元素不影响测定钍。拟定了岩石矿石中钍的测定方法,该法上柱酸度较低,操作简便,适应性广,测定范围为千分之几到百万分之几的钍。 相似文献
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<正>传统热电离质谱法准确测量土壤样品中的~(234)U/~(238)U具有较大的难度,主要原因有:①土壤中铀含量低,234U丰度小,不易准确测定;②传统的溶样方法采用硝酸溶解样品及阴离子树脂U/Th分离,由于硝酸体系中U分离系数低,使得分离回收率较低;③采用传统三带点样技术,样品中铀的电 相似文献
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TBP分离偶氮溴膦Ⅲ分光光度法测定矿石中铀 总被引：1，自引：0，他引：1
本文研究了新显色剂偶氮溴膦Ⅲ(BPA) Ⅲ)光度测定铀(Ⅵ)的条件,并结合TBP萃淋树脂分离富集较好地消除铀(Ⅵ)的伴生元素钍、稀土、锆、钙等的干扰。用于矿物中痕量铀的测定,狄得满意结果。 相似文献
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岩矿中微量铀一般采用萃取色层和离子交换色层法分离,偶氮胂Ⅲ分光光度法或2-(5-溴-2-吡啶偶氮)5-二乙基胺苯酚(Br-PADAP)-溴化十六烷基三甲胺(CTMAB)胶束增溶等方法测定。上述方法对岩矿中ppm量铀的测定操作繁杂。近年来我们利用纸色谱的特点,与干扰元素分离后直接在色谱纸上显色,用薄层色谱扫描法(或目视法)测定铀。方法简便快速,灵敏度高,可测定岩矿中0.0000x—0.00x％的铀。 相似文献
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Ion exchange resins are used successfully to extract and concentrate uranium ions from aqueous solutions although the procedures are time consuming. They utilize rather cumbersome resin columns, and consequently they have found little practical application in large geochemical surveys of isolated areas. An alternative approach using resin packages is proposed. The “package” is a teabag — convenient, cheap, disposable, and readily sealed. Laboratory and field tests indicate that the method combines simplicity, speed and economy with excellent precision and detection limits. Although the packaging procedure was designed specifically for the extraction of uranium from natural waters under field conditions, the method can be modified to extract elements other than uranium and presents a viable alternative to resin columns in a standard laboratory. 相似文献
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高纯硝酸银中痕量杂质元素的存在会影响其性能和质量,为提高现代测试技术分析痕量杂质元素的准确度,需要解决的首要问题是通过加入沉淀剂或还原剂将银除去,克服基体元素的基体效应。本文提出采用10 mL 10 g/L柠檬酸-5 g/L乙醇酸作络合保护剂,12 mL 100 g/L氯化铵作沉淀剂,建立了沉淀基体分离-电感耦合等离子体质谱同时测定高纯硝酸银中15种痕量杂质元素的分析方法。探讨了络合剂和沉淀剂浓度及用量、质谱干扰及同位素选择、非质谱干扰及内标选择、实验空白值等因素对测定结果的影响。在最佳的实验条件下,Cu、Pb、Ni、Mn、Au、Pd、Pt、Rh、Ru、Ir元素在0~100 ng/mL,Fe、Hg、Bi、Cr、Sn元素在0~250ng/mL浓度范围内呈良好的线性关系。方法检出限(3σ)为0.005~0.062 ng/g,方法精密度(RSD,n=11)为0.6%~2.6%,加标回收率为94.1%~103.1%。与现行的分析方法相比,本方法采用的络合剂和沉淀剂能将基体元素与杂质元素完全分离而不影响测定结果;实验流程简单快速,检出限低,准确度和精密度均满足了实际样品的分析要求。 相似文献
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在自行研制的低成本热电离飞行时间质谱仪(TI-TOF-MS)基础上,开展了应用TI-TOFMS法测定铀矿钻孔样品中铅同位素示踪铀矿勘查的研究。文中介绍了样品的前处理,铅的分离和富集步骤,仪器测量及数据处理等。TI-TOF-MS法测量铅同位素比值~(204)Pb/~(206)Pb、~(207)Pb/~(206)Pb和~(208)Pb/~(206)Pb的精密度分别为0.94%、0.37%和0.14%,可满足铀矿同位素示踪的要求。通过对北方某铀矿钻孔岩心取样的测量结果表明,TI-TOF-MS测量铅同位素的方法能够用于示踪铀矿。 相似文献
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稀土、钍、铀、锆、铌、钽、磷等元素的分离,以纸色层方法为简易快速[1,2]。但现有方法均采用沉淀或其它方法将稀土与大部份伴生元素分离后再进行色层分离,或经多次色层达到分离,失去纸色层方法的优越性。本文为适应微量矿物分析,利用各元素氟化物溶解度不同,一些离子的盐酸络合物可被酮类、醇类等有机溶剂萃取,及它们的分配系数各有差异,选用丁醇-氢氟酸-盐酸体系进行纸上分离,使稀土与其它伴生元素达到一次分离,然后分别进行测定。 相似文献
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高纯度的钛及钛合金具有良好的可塑性,当有杂质存在时变得脆而硬而影响其性能,准确分析杂质元素的含量有利于对钛生产工艺进行质量控制。对于杂质元素的分析,现行国家标准方法是采用样品蒸发温度较高的直流电弧作为光源,摄谱仪测定,需要经过显影、定影、测量黑度等步骤,操作繁琐,流程长,测量误差较大。本文应用中阶梯光栅和电荷耦合器件(CCD)组成的直流电弧(DC Arc)原子发射光谱仪(波长范围200~800nm),谱线干扰分析和谱线强度测量可以同时进行,能更大限度地获取光谱信息,建立了快速测定钛及钛合金中10种微量杂质元素(锰锡铬镍铝钼钒铜锆钇)的分析方法。实验讨论了测定过程中的四类谱线干扰,包括钛作为基体元素的谱线干扰、钛合金中添加的化学成分元素干扰、铁谱线的干扰、杂质元素之间的干扰,确定了适当的分析线;并应用一种浅孔薄壁细颈杯形电极装入试样,提高了样品的蒸发效果;用氯化银和碳粉的混合物作缓冲剂,提高了待测元素的谱线强度。本方法的检测范围为0.001%~0.06%,精密度小于15%,回收率为90.0%~110.0%,适合于大批量钛及钛合金样品中杂质元素的同时检测。 相似文献
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B. F. Myasoedov S. N. Kalmykov Yu. M. Kulyako S. E. Vinokurov 《Geochemistry International》2016,54(13):1156-1167
In this paper, we consider the present-day situation and outlooks of the development of nuclear power generation in Russia and other countries. It was noted that the implementation of the concept of a closed nuclear-fuel cycle accepted in Russia relies on the solution of the problem of the disposal of spent nuclear fuel (SNF) and radioactive waste (RAW). This paper presents the main results of investigations focused on the development of radiation-safe methods of manufacturing nuclear fuel elements, including mixed uranium–plutonium oxide fuel for fast-neutron reactors; creation of low waste-production technologies of SNF processing and RAW disposal; and the analysis of fundamental features of the behavior and speciation of radionuclides in environmental objects for the development of efficient methods of radioecological monitoring and remediation of radionuclide-contaminated areas. 相似文献
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为寻找有效且简单的克服基体效应的方法,我们研究了树脂吸附铀的行为:742阴离子树脂具有孔径大,吸附洗脱快等优点,本文择其吸附快之长处,对少量粉末状742树脂(280目以上)吸附铀的可能性进行了探索试验,富集分离效果良好。最终拟定在硫酸介质中以742阴离子树脂静态吸附分离铀,X-射线测量的方法,操作简单易行,方法灵敏度高、稳定。适应于地质、选冶样品中0.00X～X% 相似文献
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A novel manganese dioxide (MnO2) resin is suitable for the determination and decontamination of lead isotopes (208Pb, 207Pb, 206Pb) in aqueous solutions at trace concentrations. This is desirable due to the toxic nature and high abundance of lead in the environment. Current techniques are both time consuming, expensive and not suitable for low-level lead decontamination. The MnO2 resin has been demonstrated to pre-concentrate with extraction efficiency above 90% for a range of pH values, and with a mean extraction of 92.5% from fresh waters at a flow rate of 100?ml?min?1. The lead distribution coefficient is 1.3?×?104 (pH 7) with tolerance to calcium and sodium. Adsorption isotherms have been investigated and the resin shown to follow the Langmuir adsorption isotherm with a saturation point of 41.5?mg per g of MnO2 resin. 相似文献
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According to the present concept for final storage of spent nuclear fuel in Sweden, the spent fuel, encapsulated in copper or copper/steel canisters, will be placed in tunnels in a deep rock formation. The canisters will be surrounded by compacted bentonite clay acting as a buffer material. In connection with a safety analysis of such a storage facility, the total solubility of certain elements (e.g., uranium) as well as the transport properties (e.g., retardation due to sorption on mineral surfaces) of the long-lived radionuclides released from the canister have to be predicted or measured. The chemical conditions, governing the solubility and speciation of trace elements encountered in and around the repository depend on interactions between the ground water and the engineering materials in the repository and a production of oxidants due to radiolysis in the spent fuel. In the present study the speciation and solubility of uranium and neptunium in a bentonite-ground water system and in ground waters with compositions measured at a site at äspö, SE Sweden, have been calculated. The calculations have been carried out using a recent version of the geochemical computer code PHREEQE and the database HATCHES 5.0. Predictions of the uranium and neptunium concentrations in the ground water in the vicinity of a damaged high level waste repository have also been performed. The uranium concentration in the water in the bentonite barrier is predicted to be of the same order of magnitude or lower than that found in some granitic ground waters. For neptunium the calculations are uncertain due to the small amount of experimentally determined thermodynamic data and few verifications under the conditions (pH - Eh - carbonate concentration) considered. The predicted concentrations (ca 10–12 m, corresponds to ca 0.006 Bq/l) may be regarded as high, considering the high toxicity of neptunium and its long half-life. 相似文献