Concentrations Of Alkali Elements Research Articles

Quantitative analysis of Li, Na and K in single-element standard solutions using portable laser-induced breakdown spectroscopy

Laboratory-based laser-induced breakdown spectroscopy (LIBS) instruments have proven themselves for trace element analysis of an extensive range of elements. As portable devices have evolved greatly in recent years, new areas of field application are opening up. However, no portable LIBS (pLIBS) has yet been used for quantitative inorganic water analysis. The aim of this study was to explore whether pLIBS combined with a surface-enhanced liquid-to-solid conversion method can quantify light alkali element concentrations in standard solutions. Multivariate calibrations were performed with single-element standard solutions at detection limits of 0.006, 0.011 and 0.007 mg l −1 for Li, Na and K, respectively. Coefficients of determination ( R 2 ) for the calibration lines from 0.1 to 100 mg l −1 for Li and Na, and 0.1 to160 mg l −1 for K were between 0.96 and 0.99. It has been shown that the surface preparation technique used improves the homogeneity of the spread and shape of the evaporation residue and thus the accuracy and precision of the analysis. Hence, this study demonstrates that it is possible to quantify light alkali metals in single-element standard solutions in the range of 0.1 to 160 mg l −1 using handheld LIBS.

Spectroscopic study of the coloured gems in a 19th century pendant from Einsiedeln Abbey

AbstractNineteen green‐coloured gems adorning a cross‐shaped pendant from the end of 19th century, belonging to Einsiedeln Abbey (Switzerland), were examined using non‐destructive methods. Estimated weights of the gems are ranging from about 0.19 to 2.34 carats. Natural multiphase inclusions with jagged outlines were observed in all samples under optical microscope. Raman bands characteristic of beryl were observed in all samples with a 532‐nm laser excitation. Raman spectra of the samples with a 785‐nm laser at higher wavenumber found to be similar to emeralds containing low concentration of alkali elements. Their ultraviolet–visible–near‐infrared (UV–Vis–NIR) spectra display absorption bands related to chromium and vanadium; no absorption bands related to iron were observed. Using a combination of spectroscopic and microscopic methods, the samples were adequately identified as natural emeralds, with Colombia as their most probable source.

H2O–CO2 solubility in alkali-rich mafic magmas: new experiments at mid-crustal pressures

Volatile solubility in magmas depends on several factors, including composition and pressure. Mafic magmas with high concentrations of alkali elements are capable of dissolving larger quantities of H2O and CO2 than subalkaline basalt, which possibly contributes to large explosive eruptions. Existing volatile solubility models for alkali-rich mafic magmas are well calibrated below ~ 200 MPa, but at greater pressures the experimental data are sparse. To fill in this gap, we conducted a set of mixed H2O–CO2 volatile solubility experiments between 400 and 600 MPa at 1200 °C in six mafic compositions with variable alkali contents (Stromboli, Etna, Vesuvius, Erebus, Sunset Crater, and the San Francisco Volcanic Field). Results from our experiments indicate that existing volatile solubility models for alkali-rich mafic magmas, if extrapolated beyond their calibrated ranges, do not accurately describe CO2 solubility at mid-crustal pressures. We adapt an existing thermodynamic model to reflect our higher-pressure experimental data by determining model parameters $$\Delta {\text{V}}_{r}^{0,m}$$ (partial molar volume change of CO2 reaction) and K0 (equilibrium constant) for each studied composition. In these compositions, $$\Delta {\text{V}}_{r}^{0,m}$$ is found to vary between ~ 15 and ~ 25 cm3 mol−1, while ln K0 ranges from − 14.9 to − 14.0. The calculated solubility curves show good agreement with CO2 solubility data from the experiments and provide a more accurate description of CO2 solubility than purely empirical fits. These new experiments indicate while CO2 solubility is increased in alkali-rich mafic magmas, it is not simply controlled by total alkali content but rather the full multicomponent magma composition.

Effects of Water Leaching on the Ash Sintering Problems of Wheat Straw

Biomass energy has been used for decades in lieu of fossil fuels. However, biomass, such as wheat straw, typically contains a high concentration of alkali elements, which is likely to induce unfavorable conditions during combustion, such as slagging, agglomeration, and corrosion in the boiler. This study investigated the effects of leaching on the chemical compounds and sintering temperatures of wheat straw ash before and after leaching by tap water. Ash melting and sintering degree tests were conducted using hot-stage microscopy and a scanning electron microscope, respectively. The results show that the ash content in wheat straw decreased by 26.09% (from 4.14% to 3.06%) following leaching, as did the chlorine (Cl), sulfur (S), and nitrogen (N). Meanwhile, the ash-related elements such as potassium (K), magnesium (Mg), and silicon (Si) reduced after leaching too. Additionally, the higher heating value increased slightly, from 19.25 to 19.53 MJ/kg. At the same time, leaching improved the ash melting temperatures of wheat straw during combustion and minimized the ash sintering degree. Similar results were also shown in scanning electron microscope (SEM) images, which clearly indicated that the leached samples had a lighter sintering degree than the original samples. Overall, the leaching process had a positive effect on the ash sintering problems of wheat straw.

Elution of Cs and Sr from tea leaves (Camellia sinensis (L.) Kuntze) to green tea evaluated by PIXE analysis

We performed a particle-induced X-ray emission (PIXE) analysis of tea leaf samples (Camellia sinensis (L.) Kuntze) to evaluate the possibility of internal radiation exposure due to the intake of green tea contaminated with [Formula: see text]Cs and [Formula: see text]Sr. The tea leaf samples were obtained from tea trees (Camellia sinensis cv. ‘Yabukita’) cultivated with stable Cs and Sr added to the soil. We prepared the used leaf samples which were placed in distilled hot water (90[Formula: see text] for 1 min) as well as the unused leaf samples. The results of PIXE analysis combined with the internal standard method using Indium as a standard element showed little elution of Ca and Sr from the leaves to green tea, while the concentration of alkali elements, including Cs in the leaf, decreased by 30–40% after the tea was extracted.

The Mesozoic Caosiyao giant porphyry Mo deposit in Inner Mongolia, North China and Paleo-Pacific subduction-related magmatism in the northern North China Craton

The Caosiyao giant porphyry Mo deposit is located in the Wulanchabu area of Inner Mongolia, within the northern North China Craton (NCC). It contains more than 2385Mt of ore with an average grade of 0.075% Mo. In the Caosiyao mining district, Mo mineralization occurs mainly in a Mesozoic granite porphyry as disseminations and stockworks, with some Mo distributed in Archean metamorphic rocks and diabase as stockworks and veins. The host granite porphyry is composed of two different phases that can be distinguished based on mineral assemblages and textures: one phase contains large and abundant phenocrysts (coarse-grained), while the other phase is characterized by fewer and smaller phenocrysts (medium-grained). Zircon U–Pb–Hf analyses of the former phase yielded a concordant 206Pb/238U age of 149.8±2.4Ma with a 206Pb/238U weighted mean age of 149.9±2.4Ma and εHf(t) values ranging from −12.2 to 18.3, while the latter phase gave a concordant 206Pb/238U age of 149.0±2.2Ma with a 206Pb/238U weighted mean age of 149.0±2.1Ma and εHf(t) values ranging from −13.1 to 17.7. Five samples of disseminated molybdenite have a 187Re–187Os isochron age of 149.5±5.3Ma with a weighted average age of 149.0±1.8Ma, whereas six veinlet-type molybdenite samples have a well-constrained 187Re–187Os isochron age of 146.9±3.1Ma and a weighted average age of 146.5±0.8Ma. Thus, it is suggested that the Mo mineralization of the Caosiyao deposit occurred during the Late Jurassic (ca. 147–149Ma), almost coeval with the emplacement of the host granite porphyry (ca. 149–150Ma). The host granite porphyry is characterized by high silica (SiO2=71.52–74.10wt%), relatively high levels of oxidation (Fe2O3/FeO=0.32–0.94wt%) and high alkali element concentrations (Na2O+K2O=8.21–8.76wt%). The host granite porphyry also shows enrichments in U and K, and depletion in Ba, Sr, P, Eu, and Ti, suggesting strong fractional crystallization of plagioclase, biotite, and accessory minerals. These observations, together with high SiO2 contents and a high differentiation index (DI=89.04–92.44), indicate a strong differentiation of the granite magma.Based on geological, geochronological, isotope systematics, and geochemical studies, we propose, for the first time, a genetic model for the Caosiyao porphyry Mo deposit. Under a regional extensional setting caused by far-field tectonics related to the Paleo-Pacific subduction during the Late Jurassic, a series of geodynamic, magmatic, and ore-forming processes took place, including formation of multi-directional and multi-phase faults, emplacement of the granitic host rocks, and Mo mineralization. Highly silicic, highly oxidized, and alkali-rich granitic magma, derived from partial melting of old lower crust, intruded into the country rocks. This highly differentiated granitic magma and the exsolved ore-forming fluids, enriched in Mo, migrated upward and interacted with the wall rocks. Eventually, ore minerals precipitated in fractures, resulting in the extensive deposition of molybdenite.

Concentrations of alkali elements in green tea leaves evaluated using PIXE analysis

The concentrations of alkali elements in Japanese green tea leaves were evaluated using particle-induced X-ray emission (PIXE) analysis combined with an internal standard method to investigate the elution of radioactive cesium into green tea using potassium and rubidium. The concentrations of potassium and rubidium of used tea leaf samples were lower than those of unused samples, whereas no significant differences in the concentrations of the other elements were observed between them. In addition, we found a similarity in the relative concentrations between potassium and rubidium although the other elements showed different aspects. These results suggest that it is possible to investigate the elution of radioactive cesium into green tea using potassium and rubidium as substitutes of cesium.

In situ analysis of Na and K in a laminar premixed flame by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS) was used to in situ monitor the concentration of alkali elements in combustion environments. Particular efforts were made to optimize the temporally resolved spectra of Na and K elements. Calibration curves were constructed by relating the intensities of the specific lines to the corresponding elemental concentrations. The detection limits of Na and K elements were found to be temperature-dependent. The results indicate that LIBS can be a powerful tool for in situ monitoring Na and K concentrations in combustion environments.

Flame-retarding polylactic-acid composite formed by dual use of aluminum hydroxide and phenol resin

Abstract Flame retardancy of polylactic acid (PLA) was improved by dual use of aluminum hydroxide (AH) and phenol resin as safe flame retardants to allow PLA to be widely applied in durable products including electronic devices. Adding more than 50 weight-percent (wt%) of a specific AH which contains a low concentration of alkali elements sufficiently improved the flame retardancy of PLA. However, other important characteristics of the resulting PLA composites, such as flexural strength and fluidity, were decreased owing to the high concentration of AH. On the other hand, the simultaneous addition of phenol resins (including phenol novolac resin and tri-phenol methane resin) and the specific AH improved the flame retardancy of the PLA composites. This enhancement effect on flame retardancy, which was mainly due to the formation of homogeneous char layers produced by the phenol resins on the surface of the PLA composites during combustion, permitted the specific AH concentration to be reduced, thereby improving these characteristics of the composites. In particular, a high-molecular-weight phenol novolac resin (HMw PN resin) showed highly flame-retarding effect. While using phenol resins adversely affected the action of an organic crystalline nucleus agent for PLA, the use of HMw PN resin improved the problem because its concentration in the PLA composite was reduced due to its highly flame-retarding effect.

Studies on radioactive cesium and alkali elements in lentinula edodes (Shiitake) based on PIXE analysis

Particle-induced X-ray emission (PIXE) analysis of Lentinula edodes mushrooms (Shiitake mushrooms) contaminated with radioactive cesium was performed to study relationships between concentrations of alkali elements in the shiitake mushroom samples and their radioactive cesium levels. The shiitake mushrooms were cultivated using radiocontaminated hard wood logs due to the nuclear power plant accident in Fukushima. The significant localization of radioactive cesium was found in the pileus region of the shiitake mushroom from autoradiographic observation. The concentrations of alkali elements in the shiitake sample were measured by PIXE analysis. The PIXE analysis has shown that the concentrations and transfer coefficients of potassium and rubidium in the pileus are much higher than the other parts of the shiitake sample as is the case of radioactive cesium. It is suggested that radioactive cesium is transferred into shiitake mushrooms in a manner similar to potassium and rubidium. The results of this work have shown the possibility to be able to use rubidium as an elemental tracer for radioactive cesium.

Palaeoproterozoic A-type felsic magmatism in the Khetri Copper Belt, Rajasthan, northwestern India: petrologic and tectonic implications

A number of small Palaeoproterozoic granitoid plutons were emplaced in the Khetri Copper Belt, which is an important Proterozoic metallogenic terrane in the northeastern part of Aravalli mountain range. Contiguous Biharipur and Dabla plutons are located about 15 km southeast of Khetri, close to a 170 km long intracontinental rift zone. The plutons are composed of amphibole-bearing alkali-feldspar granites, comprising microcline-albite granite, albite granite and late-stage microgranite. The albite granite in Biharipur is confined to the margins of the pluton, and shows extensive commingling with the synchronous mafic plutonics. Geochemically, the albite granites are characterised by low K2O (∼0.5 wt.%) and elevated Na2O (∼7.0 wt.%) abundances. By contrast, the microcline-albite granite does not show any significant mafic-granite interactions and shows normal concentrations of alkali elements. The granitoids display high concentrations of the rare earth (except Eu) and high field strength elements, high values of Ga/Al (>2.5), agpaitic index and Fe*-number. These features together with their alkaline metaluminous and ferroan nature classify the rocks as typical A-type within-plate granites. All the granitoid facies display similar REE and incompatible element profiles indicating their cogenetic nature. These granitoids were emplaced in a shallow crustal chamber under relatively low pressures, high temperature (≥850 °C) and relatively oxidising conditions. The oxidised nature, HFSE concentrations and Nd isotope data (ɛNd = −1.3 to −2.9) favour derivation of these granitoid rocks from crustal protoliths. The generation of albite granite is attributed to the replacement of alkali feldspar and plagioclase of the original granite by pure albite as a consequence of pervasive infiltration of a high Na/(Na + K) fluid at the late-magmatic stage. This model may have wider significance for the generation of albite granites/low-K granites or albitites in other areas. The A-type plutonism under consideration seems to be an outcome of ensialic rifting of the Bhilwara aulacogen.

Diffusion-driven extreme lithium isotopic fractionation in country rocks of the Tin Mountain pegmatite

Lithium concentrations and isotopic compositions in the country rocks (amphibolites and schists) of the Tin Mountain pegmatite show systematic changes with distance to the contact. Both Li and δ 7Li decrease dramatically along a ∼10 m traverse from the pegmatite into amphibolite, with Li concentration decreasing from 471 to 68 ppm and δ 7Li decreasing from + 7.6 to − 19.9. Rubidium and Cs also decrease from the pegmatite contact into the country rock, but only within the first 2 m of the contact, after which their concentrations remain constant. Neither mixing between pegmatite fluids and amphibolite, nor Li isotope fractionation by Rayleigh distillation during fluid infiltration is a likely explanation of these observations, due to the extremely light isotopic composition required for the amphibolite end-member in the mixing model ( δ 7Li = − 20) and the similarly extreme isotopic fractionation required in a Rayleigh distillation model. Rather, these variations are likely due to isotopic fractionation accompanying Li diffusion from the Li-rich pegmatite (Li = 450 to 730 ppm) into amphibolites (Li = 20 ppm). The fact that other alkali element concentrations vary only within 2 m of the contact reflects the orders of magnitude faster diffusion of Li relative to heavier elements. Quartz mica schists in contact with the pegmatite also show large variations in both Li and δ 7Li as a function of distance from contact (∼1 wt.% to ∼70 ppm and + 10.8 to − 18.6, respectively), but over a longer distance of > 30 m. Lithium concentrations of the schist decrease from ∼1 wt.% adjacent to the contact to ∼70 ppm 300 m from the contact; the latter is a typical concentration in metapelites. The nature of the δ 7Li variations in the schists is different than in the amphibolites. Schists within the first 2 m of the contact have nearly identical δ 7Li of + 10, which mimics that of the estimated bulk pegmatite (+ 8 to + 11). At a distance of 30 m the δ 7Li reaches the lowest value in the schists of − 18.6 (similar to the lowest amphibolite measured). At a distance of 300 m the δ 7Li climbs back to + 2.5, which is within the range of δ 7Li of other schists in the region and metapelites worldwide. The behavior of Li in the schists can also be modeled by Li diffusion, with the effective diffusion coefficient in the schist being ∼10 times greater than that in the amphibolite. The effective diffusion coefficients of Li in the amphibolite and schist are > 2 orders of magnitude greater that those in minerals, which implicates the importance of fluid-assisted grain-boundary diffusion over solid-state diffusion in transporting Li through these rocks.

Application of multi-element statistical analysis for regional geochemical mapping in Central Japan

Some 434 stream sediment samples were collected in Central Japan for a nationwide geochemical mapping project. The resulting geochemical maps are compared with geological, mineral resource and land use maps. Spatial distribution patterns of elemental concentrations in stream sediments are determined mainly by surface geology. Elevated elemental concentrations of alkali elements, Be, Ga, Y, Cs, Ba, lanthanide (Ln), Tl, Th, and U are consistent with outcrop areas of granite, felsic volcanic rock, and accretionary complexes. High concentrations of MgO, Al 2O 3, P 2O 5, CaO, 3d transition metals, Zn, and Sr are present in sediments supplied from mafic volcanic rock, high pressure metamorphic rocks, and mafic-ultramafic rocks in accretionary complexes. A procedure is established and guidelines are set for a statistical test suite for geochemical mapping. Analysis of variance (ANOVA) and multiple comparison tests are effective for comparing means among the data subsets that are classified by parent lithological materials. Among the many procedures that have been proposed for multiple comparison tests, the Holm procedure was selected for this study. Multiple comparison statistically confirmed the correspondence of elemental abundance in stream sediments with surface geologies. However, visual interpretation of some elements is inconsistent with results of multiple comparison. According to the Holm procedure, the U content in stream sediments is affected not by granite, but by felsic volcanic rock. The Holm procedure clarifies that As, Sb, and Bi, that are not explained by the presence of mineral deposits, are enriched significantly in samples derived from accretionary complexes. Hydrothermal activity on the ocean floor might affect their levels of enrichment. Significant enrichment of Cu, Zn, Cd, Sn, Sb, Hg, and Pb observed in urban areas are also supported by the Holm procedure. The authors inferred that these sediment samples had been contaminated.

Groundwater Colloid Properties and their Potential Influence on Radionuclide Transport

ABSTRACTColloid facilitated transport is still an issue in radioactive waste management. Sophisticated phenomenological transport models are available, but progress is required to fully understand mechanisms and parameters. This study lead in this direction. Investigation of the marl groundwater colloids in steady-state conditions at Wellenberg, shows that their concentration is independent of the water flow rate. Their generation is caused by the re-suspension of the rock clay fraction only. The re-suspension process is presently being studied under flow transient conditions. Extension of our measurements to other safety relevant systems as well as a literature survey show that the colloid concentration under steady-state conditions is correlated to the concentration of alkali elements and earth alkali elements. The higher their respective concentration, the fewer colloids are occurring. Considerations on colloid contamination models are also included. The paper emphasises various colloid transport mechanisms including colloid generation from the irreversibly contaminated aquifer.

Strontium, boron, oxygen, and hydrogen isotope geochemistry of brines from basal strata of the Gulf Coast sedimentary basin, USA

Significant spatial heterogeneities exist in the stable isotopic composition of saline formation waters from reservoirs of the Smackover Formation (Upper Jurassic). We focused on the southwest Arkansas shelf, a structurally simple portion of one of the interior basins of the northern Gulf Coast sedimentary basin. Here, faulting and facies changes juxtapose dominantly oolitic carbonate strata against basal evaporites, red beds, and siliciclastics, as well as metamorphosed basement rocks. Brines from this area have exceptionally high Br and alkali element concentrations and have spatially heterogeneous hydrogen sulfide concentrations. Strontium, boron, oxygen, and hydrogen isotope compositions exhibit coherent relations with other aspects of brine geochemistry. Sr isotope compositions range from those expected for carbonates and evaporites deposited from Jurassic seawater (0.7071) to radiogenic ratios as high as 0.7107. Generally, most radiogenic Sr isotope values are associated with H 2S-rich waters which also have elevated alkali element (Li, B, K, Rb) concentrations. These alkali element-rich waters are associated with portions of the South Arkansas fault system which reach basement. Boron isotope compositions are similarly heterogeneous, ranging from values of +26 to +50%.. Brines with highest B contents are most depleted in 11B, consistent with boron input from brines generated from high-temperature siliciclastic diagenetic reactions. Normalizing B contents to Br in the brines reveals a reasonable mixing trend between a Dead Sea-type composition and Texas Gulf Coast-type shale/sand reservoir waters. Oxygen and hydrogen isotope data exhibit regional variations which are controlled by meteoric water invasion along the northern limb of the southwest Arkansas Fault, which has surface expression. Although oxygen isotope compositions are often near equilibrium with respect to reservoir carbonate, it is more difficult to ascribe trends in δD values to local water-rock interaction. The stable isotope trends can be explained either in terms of an evolved marine evaporite brine or a water evolved via water-rock interaction, and mixing with meteoric water in the vicinity of the southwest Arkansas Fault. Spatial heterogeneity in isotopic composition of formation waters from this relatively restricted study area suggests that assumptions of a homogeneous Sr reservoir in dating regional mineralization events require careful assessment in ancient systems.

Cesium and rubidium in submarine hydrothermal fluids: Evidence for recycling of alkali elements

Cs, Rb, and K concentrations have been measured in hydrothermal fluids from the East Pacific Rise (EPR), southern Juan de Fuca Ridge, and Mid-Atlantic Ridge (MAR). The results of a time series from 21°N (EPR) show a fall in the Cs/Rb ratios from 1979 to 1985. Together with results from other areas, the data are consistent with a cracking front moving from weathered oceanic crust into fresh basalt within the magma chamber that supplies the heat for hydrothermal convection. Interaction of hydrothermal fluids with basalts that have undergone low-temperature weathering results in recycling of the alkalis (and other elements) between oceanic crust and seawater. These data demonstrate that the concentration of alkali elements in hydrothermal fluids do not represent a rigid constraint on the global magnitude of the circulation of seawater through axial high-temperature hydrothermal systems.

Strontium Isotopes in some Seamount Basalts from the Northeastern Pacific Ocean

87Sr/86Sr ratios in seven seamount basalts from the northeastern Pacific Ocean range from 0.7022 to 0.7034 and correlate significantly with chemical composition as expressed by the ratio K2O/(K2O + Na2O). These basalts seem to be similar to oceanic island basalts in alkali element concentrations, 87Sr/86Sr and K2O/(K2O + Na2O) ratios suggesting similar mantle source materials, possibly least depleted in dispersed elements. However, in places, seamount basalts also appear to resemble ridge tholeiites. Large differences in 87Sr/86Sr and Rb/Sr ratios for the samples from the Cobb seamount appear to indicate isotopic variations in the source materials, perhaps resulting in the formation of different lava flows within the seamount.

Abundance and distribution of alkali elements in australites

Sodium and potassium have been determined by flame photometric methods and lithium, rubidium and caesium by emission spectrographic techniques in fourteen australites from Western Australia, South Australia and the Northern Territory. Arithmetic means of the analytical data are: Li, 42 p.p.m; Na, 0.95 per cent; K, 1.89 per cent; Rb, 84 p.p.m; Cs, 2.7 p.p.m. These figures are of the same order of magnitude as terrestrial abundances, and match the abundances in sedimentary rocks somewhat better than those for igneous rocks. The averages for sodium and potassium are virtually identical to those found by Pinson and Schnetzler (1959) for eleven philippinites and indochinites. The dispersion in concentration of the alkali elements is much smaller than in specific terrestrial rock types such as granites, but is distinctly greater than the small dispersion found in chondrites. It is a significant variation, being greater than the limits of analytical precision for the individual elements. All the elements show a close association with one another. Co-efficients of correlation ( r) range from +0.730 for the pair Li-Rb to +0.962 for the pair Na-K, and the degree of correlation is statistically “highly significant.” It is concluded that such a coherence arises from a physical process such as mixing, rather than by chemical means. A regional variation in composition, with higher concentrations of alkali elements towards the west of Australia, is observed.