锂、铷和铯吸光光度分析进展

本文以锂、铷和铯的光度测定法为主,和其它分析方法相对比,总结了光度法测锂、铷和铯。对于设备不完全的试验室及目前国内尚未有专门论文介绍锂、铷和铯的吸光光度法来说有现实意义。该论文总结全面,数据可靠。     

叔BAMBP萃取分离铷、铯新工艺

对含有丰富的锂、钾、铷、铯等有价元素的锂云母矿用石灰烧结法或氯化焙烧法提取锂盐以后,钾、铷、铯均在母液中富集,综合回收铷铯,不仅可进一步降低锂盐生产成本,而且为促进铷、铯在国民经济中的广泛应用创造了有利的条件。 国外生产铷铯盐类,大多数采用复盐沉淀法,如氯锡酸法、亚铁氰化锌法等。这类方法一般流程复杂冗长,分离效果差,产品纯度不高,收率低,生产成本高。近年来,也有采用离子交换法如AMP离子交换与斜     

中国有色金属工业总公司科技进步奖获奖项目简介

为综合利用锂云母资源,提高铯、铷、钾的分离效果,北京有色金属研究总院和江西分宜有色金属冶炼厂开展了叔BAMBP从提钾母液中分离铷、铯的工艺研究。 叔BAMBP从锂云母——石灰法提钾母液中萃取分离铷、铯新工艺,流程短,工序少;金属回收率高(铯>98％,铷>94％);原     

锂云母硫酸盐法提取锂铷铯的研究

采用硫酸盐法综合回收锂云母中的锂、铷、铯。结果表明,以硫酸钾、硫酸钙、硫酸钡作为混合盐,锂云母与混合硫酸盐质量比为1∶0.45,在900℃焙烧1h后稀酸浸出,锂、铷、铯浸出率分别为92.2%、61.5%、63.8%。浸出液经净化除杂后,浓缩沉锂,可获得零级碳酸锂,沉锂母液可用于铷、铯回收。     

采用硫酸熟化—水浸工艺从锂云母中提取锂铷铯

采用硫酸熟化—水浸工艺进行综合提取锂云母中锂、铷、铯的研究,考察了硫酸浓度、酸矿比、熟化温度、熟化时间、浸出温度、液固比等对锂、铷、铯浸取率的影响。结果表明,提取锂、铷、铯的最优工艺条件为:酸矿比1∶1、硫酸浓度70%、120℃熟化8h、液固比4∶1、50℃浸出1h。在此条件下,锂、铷、铯的浸出率分别为91.42%、88.83%、90.09%。     

宜春锂云母石灰石烧结法提锂母液中回收钾、铷、铯的研究

一、前言 江西宜春锂云母精矿除含丰富的锂外,还有较多的铷,铯、钾等有用元素。继石灰石烧结法提取锂盐的研究完成后,我们又研究了从提锂母液提取钾(钠)、铷、铯的工艺流程。提取了纯度>95％的碳酸氢钾、纯度>95％的氯比铯以及纯度>85％的氯化铷。达到了综合利用的目的。     

全国锂铷铯学术技术交流会

<正> [本刊讯] 全国锂、铷、铯学术技术交流会,于1987年6月8日至11日在广州召开。这次会议是由锂铷铯科技协作组牵头组织召开的,来自厂矿企业、科研设计院所、大专院校的科技工作者49人出席了会议。会议收到论文24篇,内容涉及近年来国内外锂铯铷科学技术的进展、生产工艺、设备研制以及理论研究等方面,特别是锂的应用和锂资源的综合开发工作又有了新的突破。     

全国锂铷铯学术技术交流会在广州召开

中国有色金属工业总公司科技协作网和科技情报网于1987年9月8～11日在广州联合召开了全国锂铷铯学术技术交流会。参加会议的49位代表在会上共交流了24篇论文。 自上次会议以来的两年时间内,锂铷铯的研究与生产均取得了很大成绩,全国锂辉石、锂云母及     

介绍新书“国外锂铷铯冶金”

“国外锂铷铯冶金”一书是我国近年所发表的有关国外锂、铷、銫冶金全面情况的仅有专著。本书共分8章,(1)锂、铷、銫的资源及技术经济情况,(2)从锂矿石生产锂盐(3)     

从锂云母浸出液中分离铷铯试验研究

采用溶剂萃取法对某锂云母浸出液中的铷、铯进行分离试验。考察萃取剂浓度、料液碱度和萃取相比对铷、铯萃取分离效果的影响。萃取分离铯、铷的较优条件为:萃取剂t-BAMBP浓度0.7mol/L、环己烷+磺化煤油为稀释剂、相比O/A=1、料液碱度0.3mol/L、萃取时间10min,铷萃取率为90.0%,铯萃取率为32.0%。负载有机相洗涤条件为:洗涤液氯化钠浓度0.1mol/L、相比O/A=1、洗涤时间10min,铷洗脱率为80.0%,铯洗损率为9.36%,分离效果较好。     

Selective Extraction of Li,Rb, and Cs and Precipitation of Lithium Carbonate Directly from Lithium Porcelain Stone

Russian Journal of Non-Ferrous Metals - The expected increase in demand for alkali metal raises a concern over the difficulty in extracting Li, Rb, and Cs from hard rock ores. A four-step process...     

Mechanism of the interaction of slimes of alumina production with carbonate solutions

In the course of laboratory investigations, it is established that slimes of desiliconization of alumina production possess selective properties with respect to alkali metals during interaction with carbonate solutions. By the magnitude of sorption by slimes, cations of alkali metals are arranged in the series Li > K > Rb > Cs. In general, selectivity of slimes is determined both by the ion-exchange properties and by the formation of binary and ternary carbonates of alkali metals and calcium.     

Off-resonance nutation nuclear magnetic resonance study of framework aluminosilicate glasses with Li, Na, K, Rb or Cs as charge-balancing cation

Framework aluminosilicate glasses with varying charge-balancing cation (Li, Na, K, Rb and Cs) have been studied with 27Al and 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) and 27Al on-resonance and off-resonance nutation NMR spectroscopy. This first application of off-resonance nutation NMR to disordered samples proves that it is a promising technique for the determination of mean quadrupole interactions in amorphous systems. Linewidths for Al decrease systematically with increasing size of the cation, due to a decrease in the quadrupole interaction from 5.0 MHz for the Li glass to 2.8 MHz for the Cs glass. A simple point-charge model effectively predicts the decrease in the quadrupole interaction. This indicates that the alkali ion is located close to aluminum. Looking at the residual linewidth after subtraction of the quadrupole broadening, the Al chemical shift distribution does not change significantly with the type of alkali ion. The same is true for the observed Si linewidth.     

Effects of alkali cations on the nuclear magnetic resonance intensity of 23Na in rat liver homogenate

Effects of alkali cations on the nuclear magnetic resonance intensity of 23Na were studied in rat liver homogenate. The loss in the resonance intensity of 23Na in the homogenate was able to be divided into two components, one of which is abolished by the addition of Cs+ ("Cs-sensitive component"), the other being insensitive to Cs+ ("Cs-insensitive component"). Both components were sensitive to guanidinium ion. In a pH range of 7.4-4.9, the Cs-sensitive component varied remarkably, but the Cs-insensitive component remained virtually unchanged. The sequence of effectiveness of alkali cations (300 mmol/kg sample) in restoring the fractional intensity of 23Na was: Cs approximately Na greater than Li approximately Rb greater than K. It was suggested that the sequences of effectiveness of alkali cations in abolishing the two components are quite different from each other. The present results were examined within the framework of a simple model. Within this framework, the results suggest that there occur, in particulate fractions, sites whose affinity for Cs+ is sufficiently lower than that for Na+.     

Distribution of 14 elements in tissues and organs of oceanic seabirds

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 microg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 microg/g dry weight).     

Adduct formation between alkali metal ions and anionic LV(V)O(2)(-) (L(2-) = tridentate ONS ligands) species: syntheses, structural investigation, and photochemical studies

Syntheses of alkali metal adducts [LVO(2)M(H(2)O)(n)] (1-7) (M = Na(+), K(+), Rb(+), and Cs(+); L = L(1)(-)L(3)) of anionic cis-dioxovanadium(V) species (LVO(2)(-)) of tridentate dithiocarbazate-based Schiff base ligands H(2)L (S-methyl-3-((5-(R-2-hydroxyphenyl))methyl)dithiocarbazate, R = H, L = L(1); R = NO(2), L = L(2); R = Br, L = L(3)) have been reported. The LVO(2)(-) moieties here behave like an analogue of carboxylate group and have displayed interesting variations in their binding pattern with the change in size of the alkali metal ions as revealed in the solid state from the X-ray crystallographic analysis of 1, 3, 6, and 7. The compounds have extended chain structures, forming ion channels, and are stabilized by strong Coulombic and hydrogen-bonded interactions. The number of coordinated water molecules in [LVO(2)M(H(2)O)(n)] decreases as the charge density on the alkali metal ion decreases (n = 3.5 for Na(+) and 1 for K(+) and Rb(+), while, for Cs(+), no coordinated water molecule is present). In solution, compounds 1-7 are stable in water and methanol, while in aprotic solvents of higher donor strengths, viz. CH(3)CN, DMF and DMSO, they undergo photoinduced reduction when exposed to visible light, yielding green solutions from their initial yellow color. The putative product is a mixed-oxidation (mu-oxo)divanadium(IV/V) species as revealed from EPR, electronic spectroscopy, dynamic (1)H NMR, and redox studies.     

High selectivity of the i(f) channel to Na+ and K+ in rabbit isolated sinoatrial node cells

The ionic selectivity of the hyperpolarization-activated inward current (i(f)) channel to monovalent cations was investigated in single isolated sinoatrial node cells of the rabbit using the whole-cell patch-clamp technique. With a 140 mM K+ pipette, replacement of 90% external Na+ by Li+ caused a -24.5 mV shift of the fully activated current/voltage I/V curve without a significant decrease of the slope conductance. With a 140 mM Cs+ pipette, the i(f) current decreased almost proportionally to the decrease in external [Na+]o as Li+ was substituted. These responses are practically the same as those observed with N-methyl glucamine (NMG+) substitution, suggesting that the relative permeability of Li+ compared with Na+ for the i(f) channel is as low as that of NMG+. When Cs+ or Rb+ was substituted for internal K+, the fully activated I/V relationship for i(f) showed strong inward rectification with a positive reversal potential, indicating low permeability of the i(f) channel for Cs+ and Rb+. These results show that the i(f) channel is highly selective for Na+ and K+ and will not pass the similar ions Li+ and Rb+. Such a high degree of selectivity is unique and may imply that the structure of the i(f) channel differs greatly from that of other Na+ and K+ conducting channels.     

Folding of an mRNA pseudoknot required for stop codon readthrough: effects of mono- and divalent ions on stability

Unfolding of an mRNA pseudoknot that induces ribosome suppression of the gag gene stop codon in Moloney murine leukemia virus has been studied by UV hyperchromicity and calorimetry. The pseudoknot melts in two steps, corresponding to its two helical stems. The total enthalpy of denaturation is approximately 170 kcal/mol, approximately the value expected for the secondary structure. At low salt concentrations (<50 mM KCl) the unfolding transitions are not two-state, but they approach two-state behavior at higher salt concentrations. The structure is preferentially stabilized by smaller alkali metal ions (Li+ > Na+ > K+ > Rb+ > Cs+) and by NH4+; the same preferences are exhibited by one of the stems in the context of a hairpin. Divalent metal ions are not required to fold the pseudoknot but do stabilize it further. To examine divalent ion effects over a wide concentration range, urea was used to lower the RNA unfolding temperature and was shown not to affect characteristics of the pseudoknot unfolding in other respects. The pseudoknot binds divalent ions somewhat more tightly than a hairpin but shows only weak selectivity for different size ions. It is suggested that a region of "intermediate" divalent ion binding affinity, in between highly ligated specific sites and purely delocalized ion binding in character, is created by the pseudoknot fold but that nonspecific, delocalized ion binding contributes at least half the free energy of pseudoknot stabilization by Mg2+.     

贵金属元素光度分析法进展

评述了近年来贵金属光度分析的进展。内容包括概述 ,水相吸光光度法 ,萃取光度法 ,动力学光度法 ,化学计量学及其它光度法等。引用文献 1 88篇。     

Ouabain-sensitive ion fluxes in the smooth muscle of the guinea-pig's taenia coli

1. Tissues with raised intracellular Na levels, produced by incubation in K-free media, were used throughout. The uptake of 42K by these Na-loaded tissues was followed for 10 min in the presence and absence of 1-37 X 10(-4) M ouabain, this being sufficient to inhibit Na pumping maximally. Subtraction of the uptake seen in the presence from that seen in the absence of ouabain gave estimates of the pumped ouabain-sensitive K uptake. 2. In Na-free (MgCl2) medium this depended on the [K]0 in a sigmoidal fashion with a half maximal [K]0 for activation of some 4mM. The maximal uptake of K was 3 m-mole/kg.min corresponding to a transmembrane flux of some 12-5 p-mole. cm-2.sec-1. 3. In the presence of Na the K activation curve became more obviously sigmoid and higher concentrations of K were needed to achieve a given active K influx. The results were well fitted by assuming that Na and K competed for two identical, non-interacting sites on the external pump face. 4. Addition of K during the efflux of 24Na into a Na-free (MgCl2) medium led to an increased rate of tracer loss. The magnitude of this increase depended on the [K] used in a hyperbolic fashion and it was abolished by addition of ouabain. The [K] causing half-maximal activation of ouabain-sensitive Na efflux was in the order of 1-2 mM. 5. When the [K] in the uptake media was 1-5 mM; Na, Li, Rb and Cs all inhibited ouabain-sensitive K uptake, the order of effectiveness being Rb greater than Cs greater than Na greater than Li. With a E1TKA10 OF 0-15 MM low concentrations of Cs and Rb were shown to stimulate K uptake. Such an effect is predicted by assuming two ion binding sites on the pump's outer face, and that the pump can translocate mixtures of K and either Rb or Cs...