Alkaline Elements Research Articles

Fluid properties and ore-forming process of the giant Jiajika pegmatite Li deposit, western China

The world class Jiajika lithium deposit in the Songpan-Ganze orogenic belt, western China is related to Late Mesozoic S-type granitic pegmatite. More than 500 pegmatite veins have been discovered in the Jiajika deposit and they show well defined zonal mineral pattern, including microcline pegmatite zone (Ⅰ), microcline-albite pegmatite zone (Ⅱ), albite pegmatite zone (III), albite-spodumene pegmatite zone (IV), and albite-lepidolite pegmatite zone (Ⅴ) from the center outward. Pegmatite Li orebodies are primarily hosted in zones III, IV and V. Barren samples of zones I and II were collected from the recent Jiajika Scientific Drilling (JSD) project performed in the years of 2020–2021 and ore samples of zones III, IV and V were collected from outcrop pegmatite veins No. 308, No. 134, and No. 528, respectively. Fluid inclusions in quartz from the Jiajika deposit include intermediate density CO2-bearing inclusions (type A), high density aqueous inclusions (type B), and low density CO2-rich inclusions (type C). Type A inclusions are predominant in zones I and II, whereas coexisting type B and C inclusions are prevailing in zones III, IV and V. Fluid inclusion microthermometry indicates that type A inclusions in zones I and II show homogenization temperatures ranging from 328 to 362 °C and salinities from 1.2 to 4.5 wt%. Type B inclusions and coexisting type C inclusions in the zones III, IV and V show homogenization temperatures of 278 to 336 °C and 301 to 358 °C, respectively. Their salinity values are 8.1 to 11.6 wt% and 0.8 to 3.6 wt%, respectively. The estimated pressures of type A inclusions are 310 to 424 Mpa, and those of immiscible type B and C inclusions are 151 to 239 Mpa. The change of fluid types with decreasing pressure indicates that extensive fluid immiscibility occurred during the formation of Li pegmatite veins in zones III, IV and V. Moreover, the LA-ICP-MS microanalysis demonstrates that chemical composition of fluid inclusions in this deposit is relatively simple, mainly containing Li, Na, K, Rb, Cs, B, and As. Such enrichment of alkaline elements (Li, Na, K, Rb and Cs) and volatile elements (B and As) is a typical geochemical index for lithium pegmatite. We suggest that the high-degree fractionated of parent magma and strong fluid immiscibility promoted the formation of the giant Jiajika Li deposit. This study highlights that immiscible fluid inclusions and strong enrichment of alkaline elements in inclusions can be an excellent tool for explorations of lithium pegmatites like Jiajika.

BaZrO3-modified (K,Na)NbO3-based lead-free piezoceramics: Enhanced electrical properties and high fatigue resistance

As legislative restrictions on the use of hazardous lead-containing materials are approaching and the demand for environmentally-benign piezoelectric materials continues to grow, there is an urgent need for viable lead-free piezoelectric alternatives. (K,Na)NbO3 (KNN)-based ceramics are environmentally-friendly, however, their piezoelectric properties still fall short of those of commercial lead-based ceramics. Herein, we report an alternative KNN material with the composition of (100-x)(K0.49Na0.49Li0.02)(Nb0.8Ta0.2)O3-xBaZrO3 + 2 wt % MnO ceramics prepared by a conventional solid-reaction approach. The addition of BaZrO3 produces finer domains and thus improves the piezoelectric and dielectric properties. MnO acts as sintering aid to reduce alkaline elements volatilization by lowering the sintering temperature. The mitigated volatilization of alkaline elements significantly reduces the concentration of oxygen vacancies, and thus contributes to enhanced piezoelectric properties. An optimal normalized strain (d33*) up to 476 pm/V at room temperature with a low driving electric field of 1.5 kV/mm is achieved at x = 4. More encouragingly, the ceramics also possess excellent temperature stability and fatigue resistance.

Separation of Cs+ from Rb+ and Cs+ co-existing solution by Cs3Bi2I9 precipitation to produce CsI

Cesium and rubidium are highly-priced rare alkaline elements that are quite difficult to separate from each other. In this paper, Cs+ was successfully separated from co-existing solutions of Cs+, Rb+ and K+ in the form of Cs3Bi2I9 precipitation. The effects of various factors (pH value, Bi3+/Cs+ molar ratio, reaction time, and decomposition temperature) on the separation ratio of Cs+ were explored. The results showed that the maximum recovery of Cs+ was 98.55% from the solution with a Cs/Rb ratio of 1.28. The content of Rb+ in Cs3Bi2I9 was 0.189%, indicating that the method can effectively separate rubidium and cesium from each other. The separation factor of cesium-rubidium was 85. By subsequent vacuum thermal decomposition, Cs3Bi2I9 was directly converted to CsI and BiI3. The purity of CsI was greater than 99.00%, and BiI3 was recycled back to produce Cs3Bi2I9. This process has the advantages of low cost, short process, environment-friendly, and simple operation.

Characteristics of Tamarind Seed Biochar at Different Pyrolysis Temperatures as Waste Management Strategy: Experiments and Bibliometric Analysis

Household activities and beverage industries that use tamarind often generate waste in the form of tamarind seeds. Tamarind seeds account for approximately 40% of the total weight of the fruit. If these tamarind seeds are not properly managed, they end up as waste with no economic or other benefits. One effective waste management strategy is to convert tamarind seeds into biochar. This research aims to examine the characteristics of biochar produced from tamarind seeds at different pyrolysis temperatures. The results indicate that as the pyrolysis temperature increases, the fixed carbon content also increases. Pores begin to form on the surface of the biochar at a temperature of 400°C. We have identified functional groups such as C-H, O-H, C≡N, C≡C, C=C, C=O, CH3, C-O, and C-C in the biochar. The dominant elements in tamarind seed biochar are K2O, CaO, P2O5, SO3, and MgO, which are part of macronutrients and alkaline elements with the potential to improve soil quality as soil amendments.

The Evolution of the REE-Bearing Özvatan Nepheline Syenite-Carbonatite Complex, Central Turkey: Mineralogical, Geochemical, and Stable Isotopic Approaches

Carbonatite complexes and associated fenite zones are famous for their high-grade rare metal ores. The carbonatite–fenite complexes generally contain high concentrations of light rare earth elements (LREE), thorium (Th), and uranium (U). While most carbonatites are closely related to continental rift zones, some complexes can be observed in post-collisional tectonic environments. The Özvatan nepheline syenite–carbonatite complex is an example of post-collisional carbonatitic magmatism in Central Anatolia, Turkey. The magmatic suite is generally composed of silica-undersaturated ultra-alkaline rocks and carbonatite dikes accompanied by high-intensity fenite zones. The carbonatites of the complex are generally dominated by coarse-grained calcite minerals accompanied by fluorite phenocrysts and may also contain minor amounts of rock-forming silicate minerals. The metasomatic aureole zones (fenites) are mainly composed of euhedral nephelines, K-feldspars, aegirines, augites, and garnets. Carbonatites of the Özvatan complex show enrichments in Ca and F with depletion of alkaline (K and Na) elements. Carbonatites and fenite zones of the Özvatan complex host a variety of incompatible elements, including La, Ce, Nd, Th, U, and Nb. The isotopic composition and general geochemical properties of carbonatites in the study area represent mantle-derived carbonatites rather than crustal limestones/skarns.

Detection of Rubidium and Samarium in the Atmosphere of the Ultrahot Jupiter MASCARA-4b

Ultrahot Jupiters (UHJs) possess the most extreme environments among various types of exoplanets, making them ideal laboratories to study the chemical composition and kinetics properties of exoplanet atmosphere with high-resolution spectroscopy. It has the advantage of resolving the tiny Doppler shift and weak signal from exoplanet atmosphere and has helped to detect dozens of heavy elements in UHJs including KELT-9b, WASP-76b, and WASP-121b. MASCARA-4b is a 2.8 days UHJ with an equilibrium temperature of ∼2250 K, which is expected to contain heavy elements detectable with the Very Large Telescope (VLT). In this letter, we present a survey of atoms/ions in the atmosphere of the MASCARA-4b, using the two VLT/ESPRESSO transits data. Cross-correlation analyses are performed on the obtained transmission spectra at each exposure with the template spectra generated by petitRADTRANS for atoms/ions from element Li to U. We confirm the previous detection of Mg, Ca, Cr, and Fe, and report the detection of Rb, Sm, Ti+, and Ba+ with peak signal-to-noise ratios (S/Ns) > 5. We report a tentative detection of Sc+, with peak S/Ns ∼ 6 but deviating from the estimated position. The most interesting discovery is the first-time detection of elements Rb and Sm in an exoplanet. Rb is an alkaline element like Na and K, while Sm is the first lanthanide series element and is by far the heaviest one detected in exoplanets. Detailed modeling and acquiring more data are required to yield abundance ratios of the heavy elements and to understand better the common presence of them in UHJ’s atmospheres.

PENGARUH ALKALI SILIKA REAKTIF PASIR TERHADAP KUAT TEKAN MORTAR RENDAMAN

Mortar is a building material made of cement, fine aggregate, and water. To get a good mortar strength, the properties, and characteristics of each of the mortar constituents must also be studied further. Aggregates containing silica can be reactive or non-reactive to alkaline elements in cement. The purpose of this study was to determine the effect of alkaline silica reactive sand on the compressive strength and flexural strength of mortar immersed in seawater. This research uses an experimental method, namely Rangkas sand, Bangka sand and Lumajang sand which have gone through the XRF (X-Ray Fluorescence) testing process to determine the percentage of compound content contained. The research method to determine the reactivity of the sand refers to ASTM C 1260. The compressive strength and flexural strength of the mortar were tested with two variations of immersion, namely by using fresh water and sea water. The immersion of the mortar was carried out for 7, 14, 28 and 56 days. From the results of testing the compressive strength and flexural strength of mortar at the age of 28 days had the same results for fresh water and seawater immersion, namely sand with high potential for reactive alkali silica has low compressive strength and flexural strength values ​​for all types of immersion. The freshwater immersion method has been used to test the mortar's flexural and compressive strength. It has a higher compressive and flexural strength value than the seawater immersion mortar, with a percentage ratio of 27.1% of compressive strength and 17.3% of flexural strength in mortar, with an immerse age of 28 days.

Individual Effects of Alkali Element and Wire Structure on Metal Transfer Process in Argon Metal-Cored Arc Welding.

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.

Mitigating alkali-silica reaction in cement mortars through microbial carbonate precipitation technique

Alkali-Silica Reaction (ASR) is a major cause of durability reduction in cement mixtures. This reaction takes place between the reactive silica contained in aggregates and the alkaline elements contained in cement (sodium and potassium), producing a hydrophilic gel known as glass water. This gel swells upon absorbing water, causing a damaging internal pressure in the mortar. This study aimed to investigate the impact of Microbial-Induced Calcite Precipitation (MICP) with Sporosarcina pasteurii on the progress of ASR in cement mortars. The mortars were made using the accelerated mortar bar method (ASTM C1260) by substituting 0, 25, 50, 75, and 100 % of aggregates with waste glass, as the extreme material causing ASR. The glass was treated by two methods named Wet Calcite Precipitation (WCP) and Fixed Calcite Precipitation (FCP), which both involved spraying 0.5 ml/cm2 of bacterial suspension on the glass. After 28 days of exposure to alkaline conditions, the mortars were examined by Scanning Electron Microscopy, X-ray Diffraction spectroscopy, and Energy-dispersive X-ray spectroscopy to verify the occurrence of ASR. The mortars were subjected to the expansion test, the ultrasonic pulse velocity (UPV) test, and the compressive strength test to measure their physical and mechanical properties. Both MCP treatments managed to significantly reduce the adverse effects of ASR (compared to the control) at the 95 % confidence level. Between WCP and FCP, WCP was more effective in improving the results of UPV and expansion tests, and FCP was more effective in improving compressive strength. The findings showed that MICP can effectively inhibit the adverse effects of ASR in cement mortars.

Enhanced piezoelectric properties for potassium sodium niobate lead-free piezoelectric ceramics prepared by microwave technology

Potassium-sodium niobate (Na, K)NbO3 (NKN) powder was synthesized at low temperature via microwave-assisted hydrothermal solovthermal method (MHSM). The resultant powder was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD results showed that pure (Na, K)NbO3 powder with a single perovskite structure was successfully synthesized when the concentration of mineralization exceeded 1 M. In order to reduce the volatilization of alkaline elements, NKN ceramics derived from 5M-powder were prepared in a microwave furnace. Microstructure, stoichiometry, and electrical properties of the obtained ceramics were investigated. The piezoelectric coefficient (d33), electromechanical coupling coefficient (kp) and remnant polarization (Pr) of the sample sintered at 1050 ℃ show optimal values of 132 pC/N, 38% and 26.3 µC/cm2, respectively. The results indicate that the microwave heating is a promising method for synthesizing and sintering NKN-based ceramics.

Static tests to assess acid mine drainage potential of copper sulfide flotation tailings

Most copper flotation tailings contain a significant amount of sulfide minerals that can generate effluent resulting from the oxidation of sulfides when they are exposed to oxygen and water. This study aimed to characterize and evaluate the acid drainage potential of five different copper flotation tailings, named samples I, II, III, IV, and V. Sample I was taken from an industrial operation, while Samples II, III, IV, and V were produced in pilot plant tests. All samples were characterized and submitted to static acid drainage tests, such as paste pH, Net Acid Generation (NAG) pH, and Modified Acid-Base Accounting (MABA). The sulfur as sulfide/total sulfur mass ratios varies from 0.40 up to 0.89 showing the presence of a high amount of minerals rich in pyrite and alunite, being higher than 13 wt% of pyrite in samples IV and V and around 19 wt% of alunite in sample III. Samples I and II presented a high number of alkaline elements, totalizing more than 8 wt% of K2 O+CaO+MgO, while samples III, IV, and V show the lowest amount of these elements (<4 wt%). Only samples III, IV, and V show Paste pH results lower than 5.0, indicating superficial oxidation on their surfaces and/or the presence of water-soluble acidity minerals. Due to the high pyrite content in samples III and IV, it was not possible to measure their NAG pH due to the high heat released with the addition of hydrogen peroxide. The low NAG pH obtained with sample III (5.30) was due to its high pyrite content (0.30 wt%) in comparison with the results obtained with sample I (NAG pH of 8.15 and 0.10 wt% of pyrite), and sample II (NAG pH of 8.18 and 0.10 wt% of pyrite). The MABA results show that samples III, IV and V presented acid drainage potential due to the neutralization potential (NP)/acidity potential (AP) ratio being lower than 1. On the other hand, samples I and II presented NP/AP ratio higher than 4, not showing potential to generate acid drainage. Due to these results, it is recommended to carry out acid drainage kinetic tests with samples III, IV, and V to determine the long-term weathering rates, evaluate lag time to acid generation and provide reaction rates for geochemical modeling.

Thermodynamic analysis of the processes of interaction and formation of nitrogen and sulfur compounds during the combustion of Kansk-Achinsk coals

The paper identifies and examines the mechanisms of the interaction of nitrogen and sulfur compounds during the combustion of Kansk-Achinsk coals (KAC). The researches were carried out on the basis of the model of extreme intermediate states (MEIS) developed at The L.A. Melentiev Institute of Energy Systems and presented in a number of publications. The KAC of various deposits characterized by different content of sulfur and mineral components are considered. On the basis of computational experiments, the influence of alkaline elements of the mineral part (Ca, Na, K) on the formation of NO and SO2 was determined. The temperature interval of the transition of condensed calcium sulfate to sulfur dioxide during the combustion of KAC of various (including new) deposits has been clarified. Based on the modeling of thermodynamic states, the results of industrial tests are considered, in which inversely proportional dependences of NO and SO2 on the resulting calcium sulfate have been recorded. These dependences can be explained by multidirectional energy flows during the formation of CaSO4/c and NOx.

Получение Al2O3 с пониженным содержанием примесей щелочных элементов

Synthesis of Al2O3 with a reduced content of impurities of alkaline elements by different treatment ways of NH4AlCO3(OH)2 was investigated. It was found that the hydrothermal treatment of NH4AlCO3(OH)2 lead to boehmite formation and further calcination of that lead to alumina formation with less content of alkaline elements to compare with Al2O3 obtained by roasting and washing of NH4AlCO3(OH)2.

Difference of flue gas desulfurization performance and desulfurization mechanism of steel slag obtained under various cooling methods

Steel slag has excellent desulfurization capacity due to its high content of alkaline. However, the current researches mainly focus on the desulfurization rate, and there is no report on the desulfurization capacity of steel slag and influence of steel slag cooling methods on desulfurization. In this paper, the difference of flue gas desulfurization performance of steel slag under three cooling methods (chilling, natural-cooling and low-cooling) were discussed through the variation patterns of pH, desulfurization rate and sulfur capacity in the desulfurization process. The order of desulfurization efficiency of steel slag with different cooling methods was chilling > natural-cooling > low-cooling. Subsequently, the desulfurization mechanism was investigated by comparing the elemental distribution and phase composition of raw materials and desulfurization products, as well as the cation analysis of the desulfurization solution. The alkaline elements Ca, Mg, Mn, and Fe in the chilled steel slag were located in the glass phase, and of them dissociated during the process of flue gas desulfurization, which was the fundamental reason for the efficient flue gas desulfurization capacity. Finally, the flue gas desulfurization performance of chilled steel slag and widely used CaO and CaCO3 were compared, and the flue gas desulfurization capacity of sharply chilled steel slag was slightly higher than that of CaCO3. Therefore, the steel slag obtained by chilling method can replace limestone, which is more friendly to the environment.

Experimental research on the properties of foamed mixture lightweight soil with red mud

Red mud (RM) is a kind of alkaline waste produced by the extraction of alumina from bauxite. According to statistics, approximately 1.5 billion tons of RM are produced worldwide annually. The existing storage methods of RM not only occupy a large number of land resources but also damage to environment owing to the presence of highly alkaline and trace heavy metal elements. This study converted wasted RM into foamed mixture lightweight soil (FMLS), a type of eco-friendly material primarily made of foam and cement. Investigations were done into the flowability, unconfined compressive strength (UCS), durability, and microstructure of FMLS with RM (FMLSR). 10 %, 15 %, 20 %, 25 %, and 30 % substitution percentages (by weight) of RM for cement were taken into consideration. The results show that the compressive strength of FMLSR was greatest when the RM replacement percentage was 20 %, and the water stability coefficient of FMLSR was greater than 0.7 when the RM replacement percentage was less than 25 %. Although the FMLSR cured for 28d generated more C-S-H gels and had a better microstructure when the replacement percentage of RM was 20 %, the UCS was still lower than that of FMLS without RM due to the relatively low Ca/Si ratio of the generated C-S-H gels. The utilization of RM not only consumes large amounts of waste and reduces environmental pollution but also frees up many land resources and reduces carbon emissions.

Assessment of nutritional approaches to nutritional requirements

The article presents the results of scientific, economic and physiological experiments conducted on Ukrainian black-spotted and red-spotted cows in different phases of lactation: Ukrainian (2009), English FIM (2004) and US NRC (2001) feeding standards. It was found that feeding dairy cows according to the Ukrainian (2009) English (FIM, 2004) and US NRC (2001) provides almost the same productivity.&#x0D; In general, in all diets, the ratio between Calcium and Phosphorus was more than 2: 1, due to the excess in the diets of Calcium in two or more times. The ratio of Potassium to Magnesium in all diets was more than three, which is recommended for cows. It was found that the cation-anion balance in the diets of dairy cows was within physiological limits. Alkaline elements were predominant acidic, ie the balance was positive.&#x0D; The concentration of crude fat in the NRC, 2001 and FIM, 2004 was significantly lower (26.3 - 53.0 %), and that the content of Calcium, Phosphorus, Sulfur, Iron, Cobalt, Manganese, Iodine and Selenium compared to Ukrainian standards in all phases of lactation. Cows that received rations according to NRC and FIM norms had higher milk productivity than Ukrainian ones, but unevenly during lactation phases.&#x0D; Thus, in the first phase of lactation, according to English standards, milk yields were 3.3% higher, and according to US standards - 3.4% lower compared to Ukrainian standards. In the second phase of lactation milk yields according to Ukrainian and English standards were almost the same. Whereas under US standards, milk yields were 6.6% higher than in Ukraine.&#x0D; In the third phase of lactation, milk yields were 3.9% higher in English standards and 8.1% higher in US standards than in Ukrainian standards.

The productivity effects of macroalgal biochar from Ulva Linnaeus bloom species on Arabidopsis thaliana Linnaeus seedlings

ABSTRACT Intensive agricultural practices and poor management of organic waste have adverse effects on aquatic ecosystems, where excessive macroalgal proliferation can occur to form ‘green tides’, with negative environmental, ecological and socioeconomic impacts. One novel method for converting a problematic material into a valuable resource is to use excess algal biomass as a feedstock for biochar production. With a high elemental composition, such a resource might be suitable to redress soil deficiencies and to ameliorate soil fertility. Green macroalgae from the Ulva genus, in bladed (predominantly U. rigida), tubular (predominantly U. prolifera) and mixed morphological (U. rigida and U. prolifera) phenotypes, were used to produce biochars. A pot trial within a controlled-environment chamber was carried out to determine the effects of amending high- and low-fertilizer compost with algal biochars (applied at 0, 0.5, 1, 2 and 5% w/w) on the growth rate of Arabidopsis thaliana. A commercial wood-based biochar was used under similar treatments as a control. Weekly imaging and final harvest weights provided additional growth data; composition data including ultimate and proximate analyses, pH, Brunauer–Emmett–Teller (BET) surface area and hydropyrolysis of the dried macroalgae and algal biochars were also conducted. Significant enhanced growth in seedlings grown with biochar amendment were not observed in high- or low-fertilizer compost, and the addition of algal biochars at 5% w/w to high-fertilizer soil significantly reduced plant growth. Elemental analysis revealed that the algal biochars contained high quantities of alkaline elements including sodium. It was hypothesised that salinity was the primary factor affecting plant growth at higher biochar application rates, despite the algae being sourced from an estuarine environment. Biochar provenance and composition is highly significant: using the catch-all term ‘biochar’ ignores both the range of materials and composition that could be used to create it and its subsequent impact within the soil. HIGHLIGHTS First plant trial using biochar predominantly from Ulva species. Negative impact seen with 5% algal biochar on plant growth. High sodium concentrations putatively identified as reduced plant growth cause.

Hydro-Geochemical Applications and Multivariate Analysis to Assess the Water–Rock Interaction in Arid Environments

Thirty groundwater samples were taken from Assiut’s northern outskirts. The physicochemical properties of these samples were investigated. For the evaluation of water–rock interaction, the saturation index (SI), chloro-alkaline indices (CAI1 and CAI2), Gibbs ratios for cations and anions (GC and GA), principal component analysis (PCA), and hierarchical cluster analysis (HCA) were used. (1) With the exception of five samples that were supersaturated, the rest of the groundwater samples were under-saturated with carbonate mineral dissolution (calcite, dolomite, and aragonite) and evaporite mineral dissolution (anhydrite, gypsum, halite, and sylvite). (2) The presence of ion exchange between alkali elements (Na+ + K+) and earth alkaline elements (Ca2+ + Mg2+) is explained by the positive values of the chloro-alkaline indices. (3) In four groundwater samples, negative chloro-alkaline indices suggest reverse ion exchange and an increasing alkali element content. (4) The Gibbs diagram demonstrates that, with the exception of four samples that reflect saline groundwater, the majority of the groundwater samples are freshwater recharging from the fresh surface water in the research area. (5) Groundwater types include Ca-HCO3 (11%), Mg-HCO3 (48%), Na-HCO3 (23%), Mg-Cl (13%), and Na-Cl (3%). (6) The alkali, earth alkaline elements, and sulphate are the key controls on groundwater salinity, according to PCA and HCA. (7) The somewhat saline groundwater in the research area’s western desert margins should not be used since it poses a health danger to people.

The Catalytic Effect from Alkaline Elements on the Tar-Rich Coal Pyrolysis

Tar-rich coal has been widely concerned because of its high tar yield. Two kinds of tar-rich coals were studied by Thermogravimetric-Mass spectrometer-Fourier transform infrared (TG-MS-FTIR) to obtain the pyrolysis characteristics. TG-MS-FTIR was used to study the mass loss, gaseous compounds evolution, and functional group information of tar-rich coal during pyrolysis. Mass loss is mainly caused by water release and macromolecular decomposition. The results showed that there were two stages of mass loss in the pyrolysis process. In addition, the gas release signal detected by mass spectrometry is consistent with the functional group information detected by FTIR. The main gaseous products include H2, H2O, CO, CO2, and CH4. In addition, the effect of ash content on the pyrolysis of oil-rich coal and the catalytic effect of internal minerals on coal pyrolysis are also discussed, and the thermal pyrolysis characteristics of coke-rich oil coal are put forward. The results provide a new idea for the study of pyrolysis characteristics of tar-rich coal.

In-situ analysis of the lithium occurrence in the No.11 coal from the Antaibao mining district, Ningwu Coalfield, northern China

The occurrence of lithium (Li) in coal serves as the foundation for understanding the mechanism of its enrichment in coal and migration during combustion. However, owing to its low atomic weight, Li cannot be detected using conventional microbeam analyses, severely limiting its use. The high-Li Antaibao No.11 coal seam with a concentration of 99.1 μg/g Li was studied to determine the mode of occurrence and enrichment of Li. When compared to Chinese coal, the Antaibao No.11 coal is richer in SiO2, Al2O3, and TiO2. The carrier of Li was preliminarily determined using statistical correlation. In addition, two high-Li coal benches were subjected to in-situ analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The TOF-SIMS data show three types of Li occurrences in the first high-Li coal sample with a content of 179 μg/g. The main carriers of Li in this sample are illite, montmorillonite, chlorite, and tourmaline, according to the chemical maps for Li, Si, Al, Na, K, Ca, Mg, and Fe. This high-Li sample was formed by the interaction of two seawater-influenced coal seams. The interaction of fresh and saline waters makes the Li occurrence more variable. However, with a Li concentration of 260 μg/g in the second Li-enriched coal sample, Li only matches with Si and Al, indicating that Li is primarily found in kaolinite. This sample is formed between the parting and the seam with the greatest transgression. Boehmite is found in this sample in relation to the bauxite-bearing weathering crust. Locally, boehmite acts as a barrier to the infiltration and interaction of Li and other alkali and alkaline elements. As a result, Li is only associated with Si and Al. The terrigenous materials deposited within the original peat are responsible for the enrichment of Li in this sample.