激光分离同位素法概述

介绍激光分离同位素的基本情况、基本方法及技术发展的基本条件。     

稳定同位素的分离与应用

介绍了国内外稳定同位素的发展以及Ｄ，＾１３Ｃ，＾１５Ｎ，＾１８Ｏ等稳定同位素的分离，并对标记化合物的生产和应用作了概述。     

同位素分离理论在硼同位素分离中的应用

离子交换色谱法是分离硼同位素的非常有前途的方法,然而工艺过程的影响因素较多,分离实验的工作量很大,为验证同位素分离理论在描述硼同位素分离中的有效性,并将其用于指导硼同位素分离过程,减少实验次数和不确定性,文中采用多柱串联色谱分离实验方法,研究了非稳态下硼同位素在色谱柱中的分布和Y.Fujii同位素分离理论在描述硼选择性螯合树脂分离硼同位素体系的有效性,并将其理论应用于制备工艺设计和验证实验。研究结果表明:Y.Fujii的同位素分离理论除可较好地描述该体系色谱带中同位素的分布情况,理论计算结果与实验数据吻合,制备验证实验的测定结果与理论设计吻合,Y.Fujii同位素分离理论能较好地指导硼选择性螯合树脂分离硼同位素体系的工艺过程。     

热扩散法分离氧同位素

<正> 热扩散法分离混合物是本世纪四十年代末发展起来的一种分离技术。由于热扩散法具有分离系数大、设备简单和容积较小的优点,因此适用于需极多分离单元、平衡时间长而产量又低的混合物的分离。     

热扩散塔分离甲烷和氢的实验研究

引言用甲烷直接合成C_2以上的碳氢化合物非常困难,例如,由甲烷脱氢合成乙烯,按热力学计算在1000K下甲烷的平衡转化率只有4.8％,所以至今甲烷仍主要用作燃料．为了充分利用这一化工基础原料,作者利用热扩散塔进行了甲烷的催化脱氢反应,使反应与分离同时进行,大幅度提高了甲烷的转化率．为考察热扩散的分离效果,本文用甲烷脱氢反应的主要成分甲烷和氢混合物为原料,在热扩散塔中分别进行了空塔和填料塔的热扩散分离实验,考察了一些操作参数对分离效果的影响,以期对反应操作条件提供必要的参考．l原理所谓热扩散现象,就是在温度场…     

利用激光法测量橡胶材料的热扩散系数及比热

用激光法对轮胎用4种胶料的热扩散系数和比热值进行了测量，在测量温度范围内，实验结果与温度线性相关。对影响误差的因素进行了分析，并用校核实验验证了装置的准确性和精确性。     

LPCE法同位素分离制备低氘水的工艺研究

液相催化交换(LPCE)法是一种操作方便高效的氢同位素分离方法。本文对LPCE法同位素分离制备低氘水的工艺进行了深入的实验研究。通过研究发现,在液相催化交换方法(LPCE)生产低氘水过程中,如果气液比达到1.5,随着温度的递增,总体积传质的系数Kya值会先升高后降低。而当反应温度一旦超过60℃,这一系数会持续地下降,因此,60℃被认为是最佳的反应温度。此外,LPCE方法在制备低氘水时候,最优气液比会因交换反应温度的不同而有所变化。气液比的增大会导致总体积传质系数Kya值上升,但是过高的气液比可能会导致气液带动,可能进一步引发液泛,从而使交换反应效率反而下降。     

锇同位素的分离与制备

对锇同位素分离与制备进行了调研和探讨。通过电磁分离实验得到锇同位素的小样，其中^187Os同位素的收率丰度为26．5％，如扣除本底污染，^187Os收集纯度达50．1％，达到一次电磁分离的国际水平。在此基础上，进一步探讨批量生产锇同位素的几种可行性方案。     

不锈钢丝螺旋圈填料塔在分离稳定同位素中的应用

<正> ~(15)N是氮元素中的一种稳定同位素。目前世界上主要采用两种方法生产~(15)N产品。其一是NO低温精馏法;其二是NO—HNO_3化学交换法。后者是以49％的硝酸和SO_2为原料,采用NO—HNO_3体系在交换塔中进行质量交换与传递。该法在常温常压下操作。生产代表国家是原民主德国和原苏联。 1 工艺流程 我们是采用NO—HNO_3化学交换法分     

离子交换色谱法分离硼同位素的研究进展

综述了离子交换色谱法分离硼同位素的进展。在目前的研究方法中,主要采用强碱性阴离子交换树脂、弱碱性阴离子交换树脂和硼特效树脂作为柱填充材料,本文对于这3种树脂的优缺点进行了比较,最后对影响单级分离因子的因素进行了讨论。表明离子交换色谱法是一种极具潜力的硼同位素分离方法,具有高效节能的特点。     

Ne同位素分离中微量杂质的气相色谱法

用气相色谱法测定热扩散法生产的Ne同位素气体的化学纯度。Ne同位素产品中的杂质主要为O2和N2(≤0.1%)及极微量的CO2、CH4、Ar、He、H2。Ne同位素产品分析过程借助控制待测气体中关键组分O2、N2的方法可以间接表征Ne同位素气体的化学纯度。实验采用H2气为载气、分子筛为固定相、柱温40.5°C,O2、N2检测灵敏度分别为0.0113%/mm、0.0331%/mm。进样方式为活动定体积进样,样品量≤2mL,平均偏差分别为0.01%、0.03%。     

Isotope Separation of Nitrogen by Ion Exchange Chromatography in a Cascade System

The ion exchange chromatography technique in a cascade process was used to separate stable isotopes of nitrogen (¹⁴N/¹⁵N). For this purpose, three column systems (with different internal diameters, S1?14.5 cm; S2–9.5 cm; S3–5.2 cm) were used that contained the cationic resins DOWEX 50 WX8 (as H⁺ and equilibrated with H₂O) and measured 1.7 m in height. Isotopic fractionation of nitrogen occurs during displacement band chromatography (DBC) of the NH₃ (aq) solution with a 0.75 mol L^?1 NaOH solution. The active sites of the resin were previously saturated to form NH₄ ⁺ (RNH₄) with a 0.75 mol L^?1 solution of (NH₄)₂SO₄ at a natural isotopic abundance (0.366 at. %) in ¹⁵N. The NH₄ ⁺/NH₃ (aq) equilibrium was determined during the DBC, which enriched the rear portion of the band with ¹⁵N. In S1, enrichment of approximately 5 at. % of ¹⁵N in the last 10 cm was achieved. After four interactions (couplings) between S1–S2, an enrichment of approximately 50 at. % of ¹⁵N was obtained. During the interaction between S2–S3, after the second coupling, an isotopic enrichment of approximately 90 at. % of ¹⁵N was observed, which produced 70 g month^?1 of (¹⁵NH₄)₂SO₄.     

Comparative Study of the Model and Optimum Cascades for Multicomponent Isotope Separation

The possibility of estimating the minimum total flow in a cascade with concentrations of a target component given in the product and waste flows by means of a model match abundance ratio cascade (MARC) is studied. The parameters required to describe MARC characteristics are the total number of separation stages, the feed flow location, and the M* parameter, which is equal to a half-sum of mass numbers of the target and the supporting components. Specific research carried out independently in two scientific labs in China and Russia has demonstrated that the integral parameters of the MARC, optimized by the M* parameter, are very close to that of the optimum by the minimum total flow cascade found by means of numerical optimization. The calculation is performed for separation of krypton isotopes when the end component ⁷⁸Kr and the intermediate component ⁸³Kr are considered to be the targets. It paves the way to use the optimized MARC parameters for two purposes: first, for fast and easy evaluation of the real cascade parameters and second, as an initial guess in its further direct numerical optimization, thereby allowing significant savings in computation time.     

离散流量离心分离级联的数值优化

在连续流量离心分离级联的数值优化上已有不少研究,从理论上提供了最优化的级联模型.但实际中级联各级的离心机台数必为整数,即各级流量为离散值,因此为了获取更好的分离效益,研究离散流量级联的数值优化,使其尽可能接近连续流量级联是十分必要的.论文比较了不同的优化方式,找到了简便高效地完成此种情况下数值优化的方式和策略.结果表明,离散流量和连续流量两种情况下最优级联的形状参数是完全一致的;具体的水力学参数并不相同,但相差不大.最后审视并改进了处理整实型变量混合优化的策略,减少了优化工作量,提高了优化效率.     

A Truly Ideal Cascade: Net Cascade

This paper reports the finding of a new type of cascade, named as net cascade, which achieves no-mixing of concentrations at any confluent point in multicomponent isotope separation. A method of realizing no-mixing is described in detail. The idea is that the cuts at a stage calculated from all components should be identical, which imposes conditions on the choice of separation factors. Solving the equation system resulting from these conditions gives the appropriate choice. Taking the separation of tungsten hexafluorideas an example, a no-mixing net cascade is constructed. Other properties of the net cascade are studied preliminarily.     

关于同位素硼-10的分离和生产

叙述了同位素硼 １０的分离技术,唯有三氟化硼—苯甲醚化学交换精馏法是当今世界美、俄等国工业生产规模所采用的技术路线。     

硼同位素开发进展与生产

采用化学交换法分离硼同位素,通过在三氟化硼—苯甲醚体系中进行了硼同位素分离生产性试验,使得硼-10同位素在液相富集,硼-11同位素在气相中富集,达到了硼同位素分离与生产目的.经过生产性试验表明：在三氟化硼—苯甲醚体系中通过级联装置可以实现硼同位素的分离,且操作稳定、连续、可靠,可用于工业化生产.硼同位素分离试生产获得了交换塔和络合塔正常运行参数;实现了在分解塔内将络合物成功分解的工艺技术;解决了物料精馏净化技术问题;验证了在交换塔内采用聚四氟乙烯丝网填料富集硼同位素可行性,试验了操作压力、流量等工艺参数对硼-10同位素富集的影响,研究了填料的性能,为实现工业化的投建打下了坚实的基础.     

Improvement in separation of the batch-type thermal diffusion column with impermeable barriers inserted between the plates

Rather than one impermeable barrier, the installation of more impermeable barriers between the plates in a batch-type thermal diffusion column substantially enhances the separation efficiency by further properly reducing the remixing effect. Theoretical analysis shows that when the barriers are installed at the best positions, maximum degree of separation, maximum concentration of the top product or minimum concentration of the bottom product may be obtained. Considerable improvement is obtained especially when the ratio K'; of transport constants (i.e. K_c/K_d) is large.     

高效固液分离设备的设计和试验

简介一种新型高效固液分离设备的构造、原理、设计、特点,探讨了设备试验过程中的现象,提出了设备的工艺设计参数。     

A Calculation Procedure for Designing Ideal Centrifugal Separation Cascades

Abstract

A numerical method is presented for determining flow rates in centrifugal isotope separation cascades that satisfy the required “ideal cascade” conditions. This method is an iterative method, which in the iteration process uses the q-iteration method to give the concentration and distributions of components under a specified hydraulic status for a cascade; and then, based on the concentration distributions, solves the algebraic equations describing the hydraulic status of the cascade to improve the specified hydraulic status towards the required “ideal cascade” conditions. The material losses in the cascade pipes and centrifuges are taken into account. Numerical simulations are performed by taking an MARC cascade with variant stage separation factors as an example. The results from four cases with and without material losses are compared. The results demonstrate that the method works very well, and show that when the material losses are nonexistent or very small, the concentration distributions can exactly satisfy the “ideal cascade” condition; but when the material losses are large, the “ideal cascade” condition can not be satisfied, but the method can produce a solution that allows the condition to be approximately satisfied.