无机离子交换剂去除放射性废水中~(137)Cs的研究进展

无机离子交换剂凭借其独特的物理化学性能,及其在去除放射性废水中137Cs的突出表现,引起人们的广泛关注。概述了硅铝酸盐、杂多酸盐、亚铁氰化物、不溶性多价金属酸性盐、不溶性多价金属水合氧化物、钛硅酸盐等不同类型无机离子交换剂去除放射性废水中137Cs的研究进展,介绍了无机离子交换剂去除放射性废水中137Cs的典型应用,以期为我国放射性废水的处理及处置提供借鉴。     

含铯废水膜处理工艺中吸附剂的选择

在含铯废水无机离子交换吸附-微滤膜处理工艺的吸附剂研究中,以134Cs为示踪剂研究了蒙脱石、蛭石及亚铁氰化锌钾对Cs的吸附效果以及体系各种因素对吸附的影响。依据研究结果,结合絮凝沉淀和中空纤维膜微滤一体化处理工艺（CMF）运行参数,从中筛选出亚铁氰化锌钾作为含铯废水膜处理工艺中的吸附剂,初步确定吸附剂投加量为0.33g/L。     

新型铯选择性吸附剂的合成及性能

在金属镍粉表面原位合成了与金属基体紧密结合的亚铁氰化镍钾(KNiFC/Ni)吸附剂。经分析,其表面为面心立方晶系的亚铁氰化镍钾(KNiFC),厚度约为40~80nm,晶格参数为0.996 0nm,化学组成可表示为K1.4Ni1.3Fe(CN)6。结果表明:该吸附剂不水解,对137 Cs具有较高的吸附容量,非常快的吸附速率,很高的选择性,Cs的吸附分配系数(Kd)可达105 mL/g,即使在1.0mol/L NaNO3溶液中,Kd值也大于103 mL/g;该吸附剂吸附137 Cs为典型的离子交换机制,NH+4由于具有和Cs+相近的离子半径所以竞争最为强烈。本吸附剂有望用于含铯废液的处理及137 Cs的分离或提取。     

CuFC吸附-微滤工艺处理含~(137)Cs废水

采用单级亚铁氰化铜(CuFC)吸附-微滤工艺去除实验模拟废水中的~(137)Cs,研究废水中~(137)Cs初始活度浓度(C0)、吸附时间、pH值、竞争离子以及CuFC投加量对去污因子的影响。分别用去离子水、地表水和海水配制模拟废水,当模拟废水中~(137)Cs的初始活度浓度分别为4.24×10~5、2.84×10~5、2.84×10~5 Bq/L,吸附时间为90min,pH值为7,CuFC投加量为80 mg/L,不投加竞争离子时,本工艺的去污因子分别达到2.06×10~4、1.62×10~4和9.36×10~1,说明CuFC吸附-微滤工艺是一种高效的含~(137)Cs废水处理工艺,且具有可观的应用前景。     

用无机离子交换法从酸性高放废液中去除铯研究进展

60年代以来人们十分关注用离子交换法从配性高放废液中去除和回收∧137Cs。本文对比和评价了沸石、多价金属磷酸盐、磷钼酸铵及其复合离子交换材料、不溶性亚铁氰化物、钛硅化合物等无机离子交换剂。结合笔者的最新研究成果,并考虑了含铯废液交换剂的进一步处置问题,提出了为我国生产堆高放废液中去除∧137Cs的无机离子交换材料,对我国的后处理中去除铯的研究提供参考。     

除Sr、Cs无机交换剂的制备及性能

为去除废液中的Sr、Cs等裂变产物,用制备的亚铁氰化铜钾和亚铁氰化钴钾无机交换剂进行了初步研究。结果显示,亚铁氰化铜钾交换剂对Sr、Cs离子的静态饱和交换容量最大值分别为80、160mg／g,对Sr、Cs离子的动态交换容量最大值分别为17、130mg／g;亚铁氰化钴钾交换剂对Sr、Cs离子的静态饱和交换容量最大值分别为80、70     

裂变放射性核素^90Sr、^137Cs分离的研究进展

对近年来裂片核素^90Sr、^137Cs的分离技术如沉淀法、萃取法、无机离子交换法等研究的进展进行评述,同时展望了可能潜在的高放废物（液）处理技术路线。对汽液矿化处理^90Sr、^137Cs废液做了简单介绍。新型高效萃取剂冠醚（DtBuCH18C6）和杯冠芳烃（BOBCalixC6）对^90Sr和^137Cs离子有比较好的选择性;绿色萃取技术如离子液体萃取技术、超临界流体萃取技术也在^90Sr、^137Cs萃取分离中得到应用。晶态钛硅酸盐（CST）和金属硫化物（KMS-1）在碱性条件下对^137Cs和^90Sr有比较高的选择性。汽液矿化处理能将含有^90Sr、^137Cs的低放废液转化成稳定的硅铝酸矿物。虽然理论上能有效地将^90Sr和^137Cs从高放废液中分离出来,但是高放乏燃料的最终处置技术还有待进一步探索。     

用钛酸盐陶瓷固化含铯亚铁氰化钛钾无机离子交换剂的初步研究

本文对在我国高放废液全分离流程中产生的含铯亚铁氰化钛钾无机离子交换剂的固化进行了初步研究。结果表明,对于含铯亚铁氰化钛钾无机离子交换剂,可先用热分解－催化氧化法除去其中的氰并将其转变为各种固体氧化物,然后用由碱硬锰矿（ＢａＡｌ２Ｔｉ６Ｏ１６）、假板钛矿（ＦｅＴｉ２Ｏ５）及金红石（ＴｉＯ２）三种矿相组成的钛酸盐陶瓷固化体对其进行固化包容。制备出的陶瓷固化体性能稳定,物理稳定性和化学稳定性与硼硅酸盐玻     

含铯亚铁氰化钛钾无机离子交换剂的分解—催化氧化法处理

含铯量较高的亚铁氰化物的固化总问题未得很好解决的主要原因是高温操作中亚铁氰根会发生分解，放出剧毒的氰气，具有较大的危险性，本研究表明，金属氧化物ＣＧ－１以氰气的氧化分解有较强的催化作用，可以很好地将含氰废气中的氰除去，使之转变为无害的ＣＯ２和Ｎ２，在此基础上提出了一个分解催化氧化法处理工艺，用以处理高放含铯废液分离流程中产生的含铯亚铁氰化钛钾无机离子交换剂，该工艺首次将含铯交换剂加热分解，然后用催     

放射性废物泥浆中~(90)Sr,~(137)Cs和~(239,240)Pu的化学形态分析

采用连接提取法和平行提取法分析了放射性废物泥浆中^90Sr,^137Cs和^239,240Pu的化学形态。实验结果表明,^90Sr主要以碳酸盐键合态和有面物键合态存在,^137Cs主要以残渣态存在,^239,240Pu主要以有机物键合态和残渣态存在。     

含草酸的硝酸溶液对锆合金的腐蚀行为

本工作模拟草酸钚沉淀母液蒸发浓缩工艺的运行条件,依据GB/T 4334.3-2000的实验要求,开展了含草酸的硝酸溶液对锆合金板材和焊件的腐蚀行为研究.采用称重法获得了腐蚀速率数据,采用扫描电镜观察金属表面的腐蚀形貌,并测定了腐蚀溶液中金属离子的浓度.结果表明:模拟实验条件下锆合金各腐蚀样品腐蚀速率均极低,测得的锆合金...     

EDXRF法测定石灰岩矿中Ca含量

介绍了用能量色散X射线荧光光谱(EDXRF)法测定石灰岩矿中Ca含量的分析方法。该方法将石灰岩矿样品粉碎,加入AgNO_3溶液反应产生AgCl沉淀,用EDXRF法测量AgCl沉淀物中Ag含量,再通过测得的Ag含量换算成Ca含量。实验结果表明:该方法测量结果的相对误差不大于0.7%,RSD不大于1.6%;与WDXRF法比较,测量石灰岩矿中Ca含量为49.28%时,其相对误差为1.38%。     

超铀元素化学形态研究现状

本文对超铀核素化学形态的研究方法及研究范围进行了总结,并指出对天然水中超铀元素形态研究化学方法主要是共沉淀法和溶剂萃取法。直接的形态研究方法比常规分光光谱法有更高的探测灵敏度,目前,在开发直接的形态研究方法上进行了很多工作。这些方法是激光致热透镜光谱法（LTLS）和激光致光透镜光谱法（LPLS）,这两种方法都是利用激光作为光源,而且提供的形态的灵敏度比常规分光光谱法高2～3个数量级。同时应用TRLFS法（时间分辨激光荧光光谱法）进行的形态实验表明了TRLFS法可用于研究发射荧光的锕系离子的地球化学的形态。     

Chromium-molybdenum steels for fusion reactor first walls — a review

Chromium-molybdenum steels have recently become of interest as a first wall and blanket structural material for fusion reactors. This application will be assessed, and possible approaches on how Cr---Mo alloys may be further developed for this application will be proposed.Generally, the Cr---Mo steels can be divided into two categories: unmodified, basically Cr---Mo---C steels and Cr---Mo---C steels modified by the addition of carbide-forming elements. Extensive research and development efforts have been conducted on the unmodified steels, especially Cr-1 Mo and 12 Cr---Mo steels. Considerable work has also been done on 12 Cr---Mo steels modified with additions of V, Nb, Ti and W. In recent years much of the research effort on this type of alloy has been directed at developing modified Cr---Mo steels with less than 12% Cr (generally 9%) for applications where the “stainless” properties imparted by chromium additions of at least 12% are not needed.We will examine the unmodified and modified steels in terms of hardenability, precipitation processes (stability at elevated temperatures), strength, and toughness. Where possible, we will discuss the effects of irradiation on these properties. Such a study leads to the types of tradeoffs that may be necessary between the well-researched unmodified Cr-1 Mo steel and a high-chromium modified steel.     

Use of a pulsed column contactor as a continuous oxalate precipitation reactor

The current objective of coprecipitating uranium, and minor actinides in order to fabricate a new nuclear fuel by direct (co)precipitation for further transmutation, requires to develop specific technology in order to meet the following requirements: nuclear maintenance, criticity, and potentially high flowrates due to global coprecipitation. A new type of device designed and patented by the CEA was then tested in 2007 under inactive conditions and with uranium. The patent is for organic confinement in a pulsed column (PC). Actually, pulsed columns have been working for a long time in a nuclear environment, as they allow high capacity, sub-critical design (annular geometry) and easy high activity maintenance. The precipitation reaction between the oxalate complexing agent and a surrogate nitrate - cerium(III) or neodymium(III) alone, or coprecipitated uranium(IV) and cerium(III) - occurs within an emulsion created in the device by these two phases flowing with a counter-current chemically inert organic phase (for example tetrapropylene hydrogen—TPH) produced by the stirring action of the column pulsator. The precipitate is confined and thus does not form deposits on the vessel walls (which are also water-repellent); it flows downward by gravity and exits the column continuously into a settling tank.The results obtained for precipitation of cerium or neodymium alone in a short column of small diameter have demonstrated that high throughputs are feasible without system malfunctions. The measured particle size of the precipitates ranges from 20 to 40 μm on average, and the measured device outflow indicates that the precipitation reaction is complete. These results suggest that this laboratory design can be extrapolated to an industrial column. Moreover, a recent test campaign demonstrated that a uranium-cerium coprecipitate easily forms when the two nitrates are mixed in a pulsed column of the same size operating under very similar process conditions. Qualitatively, the coprecipitate meets the process requirements to filter, calcine and fabricate the new nuclear fuel in the downstream steps.     

西安凹陷中南部地下热水补给的环境同位素证据

应用环境同位素方法对西安凹陷中南部深层和浅层地下热水补给进行研究,结果显示,西安凹陷中南部浅层地热水样点主要分布在大气降水线附近,个别点发生δ^18O漂移,表明其接受来自秦岭北麓现代降水和古降水的混合补给,深层地热水氚含量小于1 TU,^14C测年平均在两万年以上,表明其接受秦岭北麓全新世前古降水补给;深、浅层地下热水接受补给的方向为西南方向,补给高程为839～1746m;深层（热水埋深为1000～4000m）、浅层（热水埋深小于1000m）地下热水接受补给时的年平均温度为0．69℃,补给环境为孔隙裂隙型地下热水系统。     

气载放射性物质在采样系统管路中的沉积问题

本文叙述了核设施气态流出物采样系统中气载放射性物质（放射性气体和放射性气溶胶）在采样系统管路中的沉积问题。放射性物质在采样系统管路中的沉积，会导致实际浓度被低估，使采样失去代表性。对于气溶胶粒子的情况，在一定条件下，沉积粒子的再悬浮，又会导致采样测量结果高估气溶胶的实际浓度，同样会使采样失去代表性。作者近年在国家环保总局从事环境影响评价管理，深感解决此问题的迫切性，但在核设施的设施者和运行者中还存在一些模糊认识。本文的目的是引起有关人士对气载放射性物质，特别是气溶胶粒子在采样系统管路中沉积问题的重视和研究。     

The aging response of zirconium-tin alloys

The potential for precipitation hardening in binary Zr-Sn alloys has been examined. Transmission and scanning electron microscopy, hardness measurements, optical microscopy and X-ray diffraction were used to study alloys with the following nominal compositions: (a) 1.5%, 5%, 7% and 9% Sn, produced from Zr of iodide purity, and (b) 8% Sn, made from sponge purity Zr. Following solution treatments in the α- or β-phases, little or no precipitation response was observable under most aging conditions, including times for up to 1000 h at temperatures in the range 700 K to 1000 K. The only evidence for significant precipitation was in Zr-8% Sn, where recrystallization was induced by aging material that had been β-quenched and then cold-worked. With this treatment, precipitation proceeded in a discontinuous manner by the formation of particles, probably Zr₄Sn, at the grain boundaries during recrystallization. The resulting volume fraction was more than an order of magnitude less than expected from the phase diagram. It is concluded that the solvus line for the α-Zr(Sn) solid solution may be incorrect and the solubility of Sn is higher than previously believed. In addition, it is evident that the diffusional kinetics for phase decomposition are very sluggish. The potential for precipitation strengthening in Zr-rich Zr-Sn alloys by thermal aging is poor.     

天山北坡土壤有机碳δ~(13)C组成随海拔梯度的变化

本文选择天山北坡三工河流域作为研究区,基于碳稳定同位素技术,分析土壤有机碳(SOC)δ~(13)C值随降雨量的变化,研究不同海拔梯度土壤剖面δ~(13)C值随采样深度的变化。结果显示,三工河流域降雨量在300mm以下的采样点,SOCδ~(13)C值随降雨量的增加呈递减趋势(R2=0.97),而降雨量在300mm~500mm的采样点,δ~(13)C值随降雨量变化不明显(R2=0.04);三工河流域纯C3植物采样点土壤剖面δ~(13)C值随采样深度呈现明显的富集效应,即土壤剖面下层δ~(13)C值大于上层,其平均差值为1.01‰,与其他相关区域研究结果一致;而沙质荒漠和土质荒漠采样点剖面下层与上层SOCδ~(13)C平均差值为4.33‰,其变化趋势与纯C3植物采样点相反,且其表层δ~(13)C值接近C4植物来源,底层接近C3植物来源,推断其地上历史植被可能经历了由C3到C4的演替过程。     

The influence of precipitation conditions on the properties of ammonium diuranate and uranium dioxide powders

Continuous precipitation in one and two stages was investigated to determine the effect of precipi nation variables on the properties of ADU precipitates and the sinterability of subsequent UO₂ powders in pellet fabrication. The pH at which precipitation occurred was the most important parameter in determining the size of ADU agglomerates and the settling rate and filterability of the slurry. In two-stage precipitation, the ADU properties were determined by the proportion of uranium precipitated at different pH values. Washing nitrate from ADU appeared not to affect the properties of the subsequent UO₂ pswder but a significant decrease in filterability occurred when the ADU was extensively washed. When ADU was reduced to UO₂ at 600 °C the agglomerate structure of the ADU was retained. The larger the agglomerates in the UO₂ powder (lower pH of precipitation of precursor ADU) the less sinterable it was; pseudomorphs of large agglomerates were still discernible in the sintered pellets. Thus settling rate of the ADU slurry gave an early indication of the likely sinterability of the resultant UO₂ powder since both were functions of agglomerate size.