Alkaline Elements Research Articles

Reagentless Modified Water and Its Biological Activity

It is established empirically that bidistilled water acquires anomalous physicochemical properties when placed in strong spatially inhomogeneous physical fields. In particular, the dependences of the redox potential (RP) on рН and the dipole moment on temperature, as well as the occurrence of metastability, cannot be described within classical concepts. A model is proposed to explain qualitatively these anomalous properties. The pH of reagentless modified water (RMW) free of alkaline elements may reach 9 to 12. The electrical conductivity of this water exceeds that of its chemical analog by a factor of 8 to 30. The acid-base properties of RMW are determined by the concentration ratio of solvated protons and hydroxyls that do not enter the composition of cluster ions. In other words, RMW free of alkaline elements exhibits alkalinity. This water is shown to be biologically active: it increases the synthesis of tumor necrosis factor by immune-competent cells (both in vivo and in vitro) by a factor of 3 to 4, leads to inhibition of reverse transcriptase of human immunodeficiency virus, and promotes spontaneous hydrolysis of proteins in solutions.

Пірогенні зміни ґрунтів соснових насаджень

Унаслідок низових пожеж відбуваються зміни фізико-хімічних і біологічних властивостей ґрунтів. Досліджено пірогенні зміни властивостей ґрунтів у чистих соснових лісах, що ростуть у різних природних зонах України. У соснових насадженнях після низових пожеж у результаті як часткового, так і повного згорання підстилки утворюється попіл, що в подальшому впливає на хімізм верхнього шару ґрунту. Подібні особливості відзначали в різних природних зонах України. Надходження попелу в ґрунт призводило до зростання рН верхнього гумусового горизонту. Оскільки таке явище є одноразовим, то в подальшому після дощів значення рН водного витягу знижувалося до природнього рівня. Причиною пірогенних змін є високий уміст у попелі лужних металів. Інтенсивність змін реакції та вмісту лужних катіонів залежить від рівня згорання підстилки. Найбільш відчутними є зміни у разі повного згорання підстилки. Зазначені зміни мають поверхневий характер, тобто переважно притаманні лише верхньому шару ґрунту. На більшій глибині реакція не відрізняється від контролю.

Coordinating Ability of Anions, Solvents, Amino Acids, and Gases towards Alkaline and Alkaline-Earth Elements, Transition Metals, and Lanthanides.

After briefly reviewing the applications of the coordination ability indices proposed earlier for anions and solvents toward transition metals and lanthanides, a new analysis of crystal structures is applied now to a much larger number of coordinating species: anions (including those that are present in ionic solvents), solvents, amino acids, gases, and a sample of neutral ligands. The coordinating ability towards s-block elements is now also considered. The effect of several factors on the coordinating ability will be discussed: (a) the charge of an anion, (b) the chelating nature of anions and solvents, (c) the degree of protonation of oxo-anions, carboxylates and amino carboxylates, and (d) the substitution of hydrogen atoms by methyl groups in NH3 , ethylenediamine, benzene, ethylene, pyridine and aldehydes. Hit parades of solvents and anions most commonly used in the areas of transition metal, s-block and lanthanide chemistry are deduced from the statistics of their presence in crystal structures.

Geochemical and hydrogeological factors influencing high levels of radium contamination in groundwater in arid regions

One of the most challenging environmental issues in arid regions is radionuclide groundwater contamination; typically, radionuclide sources, mobility, and spatial distributions are not well understood. The main objectives of this study are to investigate the groundwater hydrochemistry and identify the factors governing the radium occurrences and mobility. Groundwater samples were collected from shallow unconfined zone and deep confined Saq sandstone aquifer in the Hail area, Saudi Arabia. They were analyzed for major, minor, and trace elements as well as radium isotopes (226Ra and 228Ra). The hydrochemical relationships, water facies, spatial distribution, and the factor analysis were integrated to elucidate the governing processes in the system. The hydrochemical facies exhibited four water types characterized by earth alkaline and alkaline elements. Most samples contained sulfates and chlorides. The hydrochemical processes affecting groundwater included the dissolution of certain minerals, mixing between modern and fossil water types, and reverse ion exchange. There are high concentrations of nitrate in the unconfined zone, with low concentrations in areas under confining conditions. High radium concentrations were recorded in the groundwater, and the 226Ra and 228Ra activity concentrations of the examined samples were 11% and 98% above the World Health Organization (WHO) guidelines, respectively. The spatial distribution of 226Ra showed high activity concentration in the shallow zone under prevailing oxidizing conditions. High 228Ra contamination was identified in the confined zone where the redox potential appears to decrease and the temperature increases result in higher mobility or desorption of the radium ions. In the unconfined zone, the oxidation of Fe+2 in the groundwater and precipitation of Fe+3 in the aquifer pore spaces and co-precipitation with barite can accelerate radium adsorption. The 228Ra/226Ra ratio classified the radium groundwater enrichment into three main clusters, namely, those depending on the redox potential values, the primary source distribution, and enrichment in 226Ra relative to 228Ra. Five major factors influencing groundwater hydrochemistry were identified using factor analysis. The first factor explained the processes resulting in the dissolution of the silicate minerals and thereby increased the uranium mobility. The second factor encompassed processes leading to a rise in the groundwater salinity. The third factor identified thorium minerals as the source of the 228Ra. The fourth factor was ascribed to the decrease in radium through sorption processes or co-precipitation with barite. The fifth factor referred to by the uneven distribution of Th and U containing minerals in the aquifer.

Scale deposits in tunnel drainage systems – A study on fabrics and formation mechanisms

Rapid deposition of chemical sediments, particularly calcium carbonate, is a widespread phenomenon in tunnel constructions, which can significantly disturb water draining. The removal of the scale deposits in the drainage setting is labor and cost intensive. Prediction or prevention of these unwanted scale deposits are challenging and require detailed knowledge on their site-specific source, formation mechanisms and environmental dependencies. This case study combines a mineralogical, (micro)structural, isotopic, microbiological, and hydrochemical approach to understand the formation of scale deposits in an Austrian motorway tunnel. Chemical and isotopic results revealed that all investigated solutions originate from a distinct local aquifer. High pH (11), indicative high alkaline element concentrations (Na 26 mg/l; K 67 mg/l), originated from concrete leaching, and a strong supersaturation in respect to calcite (SI > 1) are representative for the environmental setting of scaling type 1. This type is characterized by the formation of calcite, aragonite, and rarely documented dypingite (Mg5(CO3)4(OH)2*5H2O), and yields in a highly porous material showing minor indications of microbial presence. In contrast, scale deposits of type 2 are strongly microbially influenced, yielding dense and layered mineral deposits, typically consisting of calcite. The corresponding aqueous solution revealed elevated Mg concentration (38 mg/l) and a high molar Mg/Ca ratio (0.8). Scale deposits containing distinct aragonite precipitates next to calcite, mostly growing in pore spaces of the scale fabric, are accounted as type 3. Therein, dypingite is always growing on top of aragonite needles, indicative for prior CaCO3 precipitation. The composition of corresponding solutions shows the highest Mg/Ca ratio (1.1). Scale type 4 is characterized as a compact deposit consisting entirely of calcite. Its corresponding solution exhibits a molar Mg/Ca ratio of 0.6. From the obtained data sets a conceptual model was developed describing the distinct operative and (micro)environmental conditions responsible for the distinct diversity of scale deposits.

Tetragonal tungsten bronze phase thin films in the K–Na–Nb–O system: Pulsed laser deposition, structural and dielectric characterizations

Pulsed laser deposition parameters have been determined to synthesize pure Tetragonal Tungsten Bronze (TTB) phase thin films in the (K,Na)–Nb–O system (KNN). In relation to the high volatility of alkaline elements, it was found that the target composition and the target-substrate distance are of first importance. The TTB phase was identified by X-ray and electron diffraction and the surface microstructure consisting mainly of nanorods supports the formation of hallmark of the TTB phase. Poly-oriented nanorods have been obtained on both C-plane sapphire and (111)Pt/TiO2/SiO2/(001)Si substrates whereas horizontal nanorods oriented along the (hk0) planes have been grown on (100) and (110) SrTiO3. All the nanorods are parallel together when grown on (110) SrTiO3 and they present two in-plane orientations rotated of 90° from each other on (100) SrTiO3. Dielectric characteristics (dielectric permittivity εr, and loss tangent tanδ) have been measured at low (1 kHz - 1 MHz) and high (1 GHz–40 GHz) frequencies, on films deposited on Pt coated silicon and sapphire, respectively. A value of εr = 200 at 1 kHz with tanδ = 0.015 were measured in a parallel plate capacitor configuration, whereas εr = 130 and tanδ = 0.20 at 10 GHz were retrieved from transmission lines printed on the KNN TTB thin film grown on C-plane sapphire. Raman investigations of the TTB films were performed in the temperature range 77–873 K, confirming the TTB phase formation and the absence of structural transition. Piezoelectric Force Microscopy measurements evidenced a piezoelectric signal although no switching could be performed. However the dielectric measurements, complicated by high leakage currents when a DC voltage was applied, did not evidence any proof of ferroelectricity for the undoped KNN TTB films whereas results reported on other niobates (A,A′)6Nb10O30 (with A: K, Na and A’: Sr, Ba, Ca) have shown Curie temperatures, lying between 156 °C and 560 °C, separating the paraelectric phase (space group: P4/mbm N°127) and the ferroelectric one (space group: P4bm N°100).

Evolution of cations speciation during the initial leaching stage of alkali-borosilicate-glasses

AbstractAlkali-borosilicate glasses (ABS) are used as host immobilization matrices for different radioactive waste streams and are characterized by their ability to incorporate a wide variety of metal oxides with respectively high waste loadings. The vitreous wasteform is also characterized by very good physical and chemical durability. The durability of three ABS compositions were analyzed by investigating their leaching behavior using the MCC1 test protocol and these data were used to investigate the waste components retention in the altered layer and the evolution of the interfacial water composition during the test. The results indicated that the Mg species evolution is exceptional with respect to other alkaline elements and dependent on glass matrix composition and leaching progress, while transition elements speciation is fairly constant throughout leaching process and independent on glass compositions. Si and B species are changing during leaching process and are affected by waste composition. For modified wasteform sample, evolution of Mg, Si and B species is respectively constant, whereas at highest waste loading, these elements have fairly constant speciation evolution within the first 2 weeks of leaching.

Mineralization of rare metals in the lakes of East Kazakhstan

Purpose. Study on the chemical composition of lake waters, salt brines, brine and bottom sediments to identify the mineralization of rare metals and other types of minerals. Methodology. Mass spectrometric studies (mass spectrometer with inductively coupled plasma ICP-MS 7500cx from AgilentTechnologies) for the purpose of high-precision analytical studies on the chemical composition of salt lake water in order to assess the content of rare elements. The use of unmanned aerial vehicles for linking and geometrizing lakes. Findings. Field surveys on the geometrization and linking of lakes were carried out. From the materials obtained with the help of the drone, orthophotoplans were created (with a measurement accuracy of up to 1 centimeter), as well as a digital terrain model and a digital terrain model. A complex of analytical works was carried out using inductively coupled plasma spectrometry. When analyzing the distribution graphs of the absolute content of micro-components in the waters of the lakes of the Delbegeteysky massif, it was found that all samples were enriched with sodium, phosphorus, iron, magnesium and barium. The results of the analyses revealed the predominance of sulfates and chlorides in the composition of the surface waters of most of the water bodies of the Delbegeteysky massif. At the Burabai site, lake waters are characterized by an alkaline reaction of the environment (on average = 8.71). At the same time, the salinity of water bodies varies from 05 to 9 g/dm3. Originality. Large-scale outcrops of granites of the Kalba complex (P1), with which a rare-metal type of mineralization is genetically associated, are known to be on the selected study sites. Quartz-wire-greisen and quartz-wire tin, tin-tungsten and tungsten formations are also widely developed. Considering the large geochemical migration ability of rare alkaline elements in the thickness of loose sediments as a result of intensive geodynamic processes in the East Kazakhstan region, it is possible to assume the possibility of their migration to the upper horizons and accumulation in salt lakes localized within the area of development of granite intrusions of Permian age and associated deep tectonic faults. Practical value. The results of the research can serve as a revival of the rare metal industry in the region, which will allow developing new high-tech industries and creating new jobs in this area. The obtained results can be used for setting up further exploration and operational work on the selected promising areas.

Using Petrogeochemical Modeling to Understand the Relationship between Paleozoic Magmatism in the Kola Region and Its Precambrian History

The Kola region hosts numerous Paleozoic massifs of ultrabasic alkaline rocks and carbonatites with deposits of commercially valuable metals, such as iron, tantalum, niobium, and rare earth elements. These magmatic complexes are characterized by high contents of alkaline elements at generally low contents of SiO2 and/or Al2O3. In this study, we examined the precursors to the formation of the unique Paleozoic alkaline province through studying the early Precambrian stages in the evolution of the Kola collision area, from where these unique features probably originated. We mathematically modeled the changes in the chemical composition of these rocks. The obtained data can be used for metallogenic forecasting, which indicated a number of Precambrian objects in the region, namely, the Lapland Granulite Belt of the Kola region and granulite belts in Eurasia. The mathematical modeling performed during this research depicted a linear trend that defined the style of the changes in the chemical composition at the transition from the metaultrabasic-basic rocks of the Lapland granulite belt to the group of belts in Eurasia. These differences are statistically significant with respect to the obtained trend (chemical composition projected on the trend), mainly manifested as increased SiO2 and Al2O3 contents with a decreasing total alkalis content, which is opposite to the indicated trends of the changing chemical composition in the Paleozoic alkaline rock units of the Kola region. We concluded that one of the reasons for the unique composition of the Paleozoic magmatism products could be a specific feature of the earlier Neoarchean stages of the tectonic-magmatic activity in the northeastern Baltic Shield, which implies a close relationship between later geological events and the early Precambrian history, at least in the study area.

Little precious lithium?

Lithium is on everybody´s lips these days, due in part to the 2019 Nobel Prize in Chemistry awarded to our own EQ Board member M. Stanley Whittingham and co-recipients John B. Goodenough and Akira Yoshino for their research in breakthrough battery technology. Lithium is the lightest metal and, like other alkaline elements, it is highly reactive. Thus, it occurs only in its oxidized form. Because of its many interesting properties—high electropositivity, low weight, relative stability—lithium is widely used in the production of polymers, as antidepressants, as a fusion fuel candidate, as flux in ceramics and glasses, and as a “rocking chair” intercalating ion in Li-ion batteries. Li-metal batteries, which would be even more effective, unfortunately are not reliable and safe enough to be applied broadly. The transition from combustion-based to electric mobility in transportation raises the question of increasing demand and limitations of new material supply chains. Lithium might become a very critical element, although it is abundantly found even in oceans because of its water solubility. Geological lithium resources are not easy to quantify—the published data vary according to political whims—but are certainly abundant: at least 15 million metric tons of reserves are proven. Lithium extraction from brines and hard-rock mines, currently around 40,000–50,000 metric tons, will increase dramatically along with the price of battery-grade lithium salts. Better technologies will be required at the extraction sites to safely provide larger amounts of this future high demand material and, therefore, more and more precious raw material. Until now, recycling lithium has not been an economical option. However, as the demand for raw material for millions of new Li-ion batteries increases—for the storage of electricity from newly installed renewable energy sources and for the huge number of new electric vehicles—the number of end-of-life batteries will pile up. The Li-ion battery industry will require efficient recycling, reuse, refurbishment, and electrode regeneration to limit the environmentally intense mining of lithium. The regeneration of lithium-containing materials and effective extraction of lithium from ceramics, glass, ores, and e-waste by efficient delithiation, mechanochemical, soft hydrometallurgical, electrochemical, bioleaching, or solvothermal processes will avoid the deposition of lithium salts and prevent the increasing dissipation of lithium in the environment. Because lithium wastes are partly water-soluble and might be toxic or could interfere in other unforeseen ways with the biosphere, follow-up problems for human beings cannot be excluded. Only intense materials research for an efficient circular economy and green chemistry recycling processes will guarantee a waste-neutral future as well as a smooth energy transition to prevent new waste-related problems, such as CO2 dissipation-initiated climate change, for lithium.

Extra CO2 capture and storage by carbonation of biomass ashes

Eight biomass ashes (BAs) produced at 500 and 900 °C were studied to definite their composition, phase transformations, carbonation-decarbonation behavior, and CO2 capture and storage (CCS) potential. Light microscopy, powder X-ray diffraction, scanning electron microscopy, as well as differential-thermal, thermo-gravimetric and chemical analyses were used for that purpose. It was found that most of the BAs studied have high contents of alkaline-earth and alkaline elements represented by carbonates, bicarbonates, oxyhydroxides, chlorides, sulphates, phosphates, and inorganic amorphous material, and such minerals and phases have a key role for CCS by BA. There is an intensive formation of newly formed carbonates as a result of solid–gas reactions between alkaline-earth and alkaline oxyhydroxides and volatile CO2 formed during biomass combustion. Subsequently, additional post-combustion carbonates and bicarbonates are formed by both solid–gas and solid-liquid reactions between the unreacted oxyhydroxides and carbonates in BA and CO2 occurring in air and water during BA storage. The decomposition temperature of carbonates is mostly at 600–900 °C and the mass loss measured in this temperature range approximately determines the CO2 volatilization from the carbonates in BAs. The measured CO2 volatilization (or CCS) for the BAs studied is between 1 and 27% (mean 11%). It was emphasized that the biomass energy can be not only carbon-neutral, but also with some extra CCS potential due to fixation and immobilization of atmospheric CO2 in BA. Therefore, the future large-scale bioenergy production can contribute enormously for reducing CO2 emissions and can decrease or eliminate the application of expensive technologies for CCS.

Dissolution-Induced Surface Roughening and Oxygen Evolution Electrocatalysis of Alkaline-Earth Iridates in Acid

Summary Alkaline and alkaline-earth iridates have garnered much attention, as they can outperform traditional IrO2 for oxygen evolution electrocatalysis under acidic conditions. Despite the advantages of their catalytic properties and significant reduction of Ir utilization, dissolution of alkaline and alkaline-earth elements into acid media can be a serious drawback that may confine long-term applications. By using atomic-column-resolved scanning transmission electron microscopy, we demonstrate the surface variations of three alkaline-earth iridates, AIrO3 (A = Sr or Ba). Directly identifying the structural transformation into metastable nanocrystallites or an amorphous state, we elucidate that substantial surface roughening can be induced by alkaline-earth elemental leaching. In particular, ∼20-fold increases in the active surface area in pseudocubic SrIrO3 and monoclinic BaIrO3 are notable structural features. Our findings emphasize both the impact of surface structure on the overall catalytic activity and consequently the important control of chemical leaching to attain a high surface area in iridate-based catalysts.

Low work function Ca doped graphene as a transparent cathode for organic opto-electronics and OLEDs

Graphene is an excellent candidate for a transparent electrode since it has high lateral conductivity and optical transparency, but due to its high work function, between 4.5 and 5eV, it can serve as a good transparent anode but poor transparent cathode due to a barrier for electrons injection. Reducing graphene’s work function is thus essential to make it an ideal transparent cathode as well. Naturally, n-type doping of graphene increases its Fermi level and thus reduces the work function. Among many choices of n-type dopants alkaline element can be good candidate, here we present a study of calcium (Ca) n-doped graphene to be serve as a transparent cathode. Several measurements were carried out on Ca doped graphene and compared them with pristine graphene as a reference, such as: Raman spectroscopy, x-ray photoelectron spectroscopy (XPS) Field effect transistor (FET), transparent electron microscopy (TEM), and photoemission spectroscopy. Our results show that doping graphene with 1 nm of evaporated Ca on the surface reduces its work function by nearly 1eV. We further performed current-voltage characteristics of graphene/Alq3/Ag structures having undoped and doped graphene cathodes. The structures with doped graphene showed an increase of two orders of magnitude in current under the same applied bias due to the contacts barrier reduction. The results confirm the effectiveness of Ca-doped graphene for reducing the barrier for electron injection from graphene to next adjacent organic layer. It demonstrates the feasibility of Ca doped graphene to serve as a transparent cathode in organic devices in general and in OLEDs in particular.

Change of electrophysical properties of the Si(111) and Si(100) surface in the process of ion implantation and next annealing

The change in the electrical properties of the Si(111) and Si(100) surfaces during ion implantation and subsequent annealing was studied. The possibilities of controlling of the electrophysical properties of the Si(111) and Si(100) surface layers by the implantation of ions of alkaline and alkaline-earth elements are analyzed. Some electrophysical properties of semiconductors containing p- and n-structures and the possibilities of their application in electronics are discussed.

МИНЕРАЛОГО-ГЕОХИМИЧЕСКИЕ ОСОБЕННОСТИ ИСТОЧНИКА ЯМКУН (ЗАБАЙКАЛЬСКИЙ КРАЙ)

Актуальность. Источник Ямкун известен как один из немногих радиоактивных источников на территории Забайкальского края. Его воды ранее использовались для лечения болезни Кашина–Бека (уровской болезни), в настоящее время на его базе функционирует краевой центр медицинской реабилитации для лечения заболеваний костно-мышечной, нервной систем, в том числе ДЦП, а также заболеваний кожи. Цель: выявление минералого-геохимических особенностей компонентов источника Ямкун. Объекты: воды озера, ручья, травертины, железистые осадки в русле ручья, солевые отложения на трубе каптажного колодца, растительность (лишайники, мхи, хвоя сосны, листья тополя). Методы: масс-спектрометрия с индуктивно связанной плазмой, инструментальный нейтронно-активационный анализ, рентгеновская дифрактометрия, сканирующая электронная микроскопия. Результаты. Воды источника Ямкун являются гидрокарбонатными кальциево-магниевыми, радиоактивными радоновой природы Они существенно обогащены Mn, Fe, Be, As, Zr, Cs, Hg, Tl, Li, Co, Ba относительно воды оз. Байкал. Обогащение воды редкими щелочными и щелочноземельными элементами (Li, Be, Cs), а также Hg, Tl, As и Zr позволяет предположить, что их источником являются редкометалльные гранитоиды. При разгрузке вод наблюдается современное минералообразование в виде «ямкунской пены» (арагонит) на поверхности водных ванн, трубах каптажного колодца (несквегонит) и ручье (железистые осадки). Железистые осадки и травертины представлены в основном магнезиальным кальцитом. При этом в железистых осадках выявлены в больших количествах соединения Fe и Mn, вероятно гидроксиды. В гидроксидах Mn встречаются также соединения Ba, K, Cl, в гидроксидах Fe – As, P, Si, Al. Из редких микровключений в травертинах отмечены интерметаллические соединения Cu и Sn, La-Ce карбонат, а также сульфид As (леллингит?). Установлена унаследованность состава современных железистых осадков и травертинов. Образующиеся травертины обогащены теми же элементами, что и вода в источнике.

Аналитическое описание удельной электропроводности расплавов галогенидов KHal и расчет ее для расплава KAt

In this paper, the analytical description of the specific conductivity of the potassium halogenides melts KHal (Hal – F, Cl, Br, I) is presented. The analitical description is provided on dependence of the specific conductivity on the halogen order number ӕ = f(Z), the ionic radius of halogen-ion ӕ = f(r), the ionic potential ӕ = f(1/r), the electronegativity difference ӕ = f(∆χ) ((∆χ = χ (Hal) – χ(K)). The interrelation of a reduced property with an order number ӕ/Z = f(Z) is considered. According to the obtained analytical dependencies, the calculation of the value of the potassium astatide specific conductivity is given for temperatures above the melting point on 5, 10, 50, 75, 100, 150 и 200°, in literature Information for KAt absent. The calculation was carried out using comparative methods for calculating M.Kh. Karapetyan in the coordinates of "property-parameter" and "property-property." Least squares method was applied for processing the analytical description results with the choice of optimal dependencies on the maximum correlation coefficient and the minimum standard deviation. The analysis of the interrelation of the calculated numerical values with similar characteristics for NaAt и LiAt is presented. Comparison of the specific conductivity obtained numerical values of the astatide potassium melt showed good consistency with the values ӕ obtained from the straight line dependence ӕТпл+n = a∙ ӕТпл+5 (n = 10°…200°) and also with similar characteristics for lithium astatide and sodium astatide. The analytical calculation results allow to describe the temperature dependence of the potassium halogenides specific conductivity, including KAt. The calculation method can be used to describe the melts specific conductivity in the same type series of compounds of alkaline and alkaline-earth elements that make up electrolytes for chemical current sources.

Geochemistry of sillimanite-magnetite-kaolinite of metasomatic rocks of the island of Great Tyuters (gulf of Finland, Russia)

Among the secondary quartzites of the island of the Great Tyuters there are extended linear zones with a capacity of up to 3 meters, clearly visible in detailed satellite images. They are composed of sillimanite-magnetite-kaolinite metasomatites discovered for the first time. The formation of metasomatites is associated with fragmentation of quartzites and the subsequent introduction of fluids of a substance saturated with various components. Metasomatites are enriched with Al2O3 (16–23 wt.%), in contrast to 2–5 wt. per cent of this oxide is present in their substrate – quartzite. In metasomatic rocks dominated by iron oxide, quartzite – ferrous. The rocks do not contain any alkaline and alkaline-earth elements. They are enriched with Zr (146–199 g/t) and a number of other elements, including impurities and rare earth, among which prevail Ce (34 g/t) and La (17 g/t). REE of both breeds is characterized by a small and close degree of fractionation ((La/Yb)n=6.55 and 6.17). Metasomatites on a set of minerals do not differ from quartzites, but differ in their quantitative ratios and composition. Of particular interest is the magnetite of metasomatites. It contains many quartz inclusions with kaolinite edges. Quartz inclusions, in turn, contain inclusions of titanium magnetite crystals. In the formation of metasomatites, there were several stages of the metasomatic process with a changing composition of fluids and different acidity-alkalinity of the mineral formation medium. The development of metasomatites in linear zones, the disintegration of their substrate, the high content of kaolinite – all this gives them a similarity with weathering cows. However, the same set of minerals in metasomatite and its substrate, the complete absence of sulfides and sulfur, the presence of magnetite with double mineral inclusions – such features distinguish these rocks from the classical weathering crust.

Microstructural Evolution of Blast Furnace Coke During Experimental Heating \u2014The IFORS Approach

Blast furnace coke has been experimentally heated between 850 °C and 1100 °C by varying the gas composition and the alkali content of the raw coke. Raman spectroscopy and “Iterative Fitting of Raman Spectra” (IFORS) evaluates the microstructural change of coke during the experiments. The obtained results indicate a significant microstructural variation within a bulk sample. This variation controls significantly the coke quality as estimated from standard experiments (23.9 < CRI > 38.3). A bulk sample with a CRI value <30 is composed dominantly of lumps showing a relatively low structural ordering. During experimental heating, the structural ordering of such lumps increases. A bulk sample with a CRI value >30 is composed dominantly of lumps showing a relatively high structural ordering. During experimental heating, the structural state of such lumps remains unchanged unless a strong reaction is induced by adding alkaline elements. It is supposed that, under laboratory conditions, thermal and chemical energy, affecting a microstructurally low-ordered coke, first reorganizes the structural state of the individual coke lumps, retarding the onset of the Boudouard reaction.

Aquatic environment and anthropogenic factor effects on distribution of trace elements in surface waters of European Russia and Western Siberia

The distribution of trace elements of anthropogenic origin, especially toxic metals, is an environmental problem. We present the first results of research into the geochemistry of lake waters and metallic pollution in European Russia (ER) and Western Siberia (WS), based on a survey of 367 lakes from the tundra to the steppe zones. The content of more than 80 elements in the lake water was studied; the influence of airborne contamination and the geochemistry of water were estimated. We found that the concentrations of alkaline and alkaline-earth elements, as well as As, V, Co, U, Nb, Sb, increase with a change in the climatic gradient. This fact is explained not only by airborne contamination, but also by the geochemistry of lakes and the climatic factor (increased evaporation concentration). Anthropogenic eutrophication leads to an increase in the content of Fe, Sr, Mo, and acidification—Zn, Cd, Ni, Cu, and especially Pb. There are industry-specific influences: the waters of the northern regions of ER are enriched by Ni, Cd, As, Sb and especially Se because of the emissions from copper-nickel smelters. The oil and gas industry (WS) leads to increased concentrations of V, Pb and Mo in water. We assess the metallic pollution status of surface water in the Eurasian region of Russia using an enrichment factor (EF). In surface waters of ER and WS, metal concentrations do not exceed the maximum permissible concentration, but we have established higher concentrations of many elements in the background, including toxic ones. Prolonged low doses of toxic elements can be a potential hazard to ecosystems and humans. The results showed that from the northern to the southern regions the EF increases for most of the analyzed elements. It can be assumed that with climate warming the concentration of metals in these bodies of water will increase and this is dangerous for the environment.

Mechanical, in-vitro biological and antimicrobial characterization as an evaluation protocol of a ceramic material based on alkaline activated metakaolin

The study aimed to correlate mechanical, physical and biological properties (in-vitro) of a ceramic material, based on alkaline activated metakaolin (MK) and CaCO3, to be used in the health sector. The designed materials reached compressive strengths in the range of 18 MPa to 29 MPa, after 7 days of curing, and porosity between 50 and 30%. The higher strength materials were subjected to a reactivity test for the formation of a layer of hydroxyapatite in the presence of simulated body fluid (SBF). By means of scanning electron microscopy, the in-situ growth of rounded crystals was identified, indicating the presence of elements such as Ca and P in its chemical composition. For the evaluation of the biological and anti-bacterial response, a system with the capacity to form a calcium phosphate layer on its surface was selected, with an increase in the pH value of the SBF solution and a compressive strength of at least 25 MPa. The results of the biological protocol showed that the material, due to its high pH, generates haemolysis or the rupture of red blood cells, indicating that the developed material needs to be modified in its chemical composition to decrease the high pH or to guarantee, by means of an additional processing stage, to decrease leaching of alkaline elements to the body fluid and thus not cause harmful effects on the human body. On the other hand, after being evaluated against several bacteria it was identified that the material had an inhibitory effect on Pseudomonas aeruginosa which makes suitable the material to be used in external applications.