High temperature (35)Cl nuclear magnetic resonance study of the LiCl-KCl system and the effect of CeCl3 dissolution.
High temperature (35)Cl nuclear magnetic resonance study of the LiCl-KCl system and the effect of CeCl3 dissolution.
复制标题
高温(35)Cl核磁共振研究LiCl-KCl体系及CeCl3溶解的影响。
DOI：
10.1039/c6fd00003g
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发表时间：
2016
影响因子：
3.4
通讯作者：
Zhang H
中科院分区：
文献类型：
--
作者：
Zhang H
本文研究了LiCl-KCl系统在一定温度范围内的动力学，以了解在熔盐高温处理过程中，这些系统中的常见离子氯周围的局部结构。氯-35核磁共振（NMR）对共振核的局部环境及其在扩散时标上的运动敏感。因此，它是一个很好的探针的原子尺度过程控制这些熔盐的粘度，扩散系数和电导率。利用高温核磁共振（NMR）谱，从室温到890 °C，在KCl浓度为0-100 mol %的范围内，以10 mol%的间隔，测定了（Li，K）Cl盐混合物中~（35）Cl的平均各向同性化学位移（~（35）Cl δ）和自旋-晶格弛豫时间（T1）。两种端员盐中的~（35）Cl δ与固体卤化物中的阳离子-阴离子半径比一致，平均阳离子-阴离子半径比可以用来解释~（35）Cl δ随组成的变化。四极相互作用被认为是负责的自旋-晶格弛豫的35 Cl，和T1弛豫的激活能已获得的所有组合物。测得的T1（35 Cl）活化能不随组成线性变化，并在50%KCl处达到峰值，这也与该系统的Chemla点相一致。它们也与等效电导率测量值吻合良好。为了研究系统对溶质的响应，将8重量%的CeCl 3添加到纯LiCl中作为替代锕系元素。诱导的位移为120 ppm，T1（35 Cl）的活化能增加了四倍。这是一个有前途的初步结果，为探测这些高温处理盐的动力学上的锕系元素溶解的效果。
This paper examines the dynamics of the LiCl–KCl system over a range of temperatures in order to understand the local structure surrounding chlorine, which is the common ion in these systems, during molten salt pyro-processing. Chlorine-35 nuclear magnetic resonance (NMR) is sensitive to the local environments of the resonant nuclei and their motion on a diffusive timescale. Thus, it is a good probe of the atomic scale processes controlling the viscosities, diffusivities and conductivities of these molten salts. The average isotropic chemical shifts (35Clδ) and spin-lattice relaxation times (T1) of 35Cl in (Li,K)Cl salt mixtures have been obtained over a compositional range of 0–100 mol% KCl with an interval of 10 mol% using high temperature nuclear magnetic resonance (NMR) spectroscopy from room temperature up to 890 °C. The 35Clδ in the two end member salts are consistent with the cation–anion radius ratio as previously measured on the solid halides and the average radius ratio of cation to anion, can be used to explain the variation of 35Clδ with composition. The quadrupolar interaction is found to be responsible for the spin-lattice relaxation of the 35Cl, and the activation energies for T1 relaxation have been obtained for all compositions. The measured T1 (35Cl) activation energies do not vary linearly with composition and peak at 50% KCl, which also coincides with the Chemla point for this system. They also are in good agreement with the values from equivalent conductivity measurements. To investigate the response of the system to solutes, 8 wt% of CeCl3 was added to the pure LiCl as a surrogate actinide. The shift induced was 120 ppm and the activation energy for the T1 (35Cl) increased by a factor of four. This is a promising preliminary result for probing the effect of actinide dissolution on the dynamics of these pyro-processing salts.
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DOI：
10.1098/rspa.1947.0016
发表时间：
1947
期刊：
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
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DOI：
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