Major Minerals Research Articles

Thermodynamics and mechanisms of silver tailings roasting processes

To separate and extract all the useful components of tailings, taking silver tailings as the object, the thermodynamics of silver tailings during the roasting processes was investigated, and the phases transformation mechanism of major minerals were obtained. Based on the mineralogy characteristics of silver tailings, the standard Gibbs free energy changes for the chemical reactions in the roasting processes were calculated; the thermal chemical behaviors and the mineral phases transformation were investigated using TG/DTG-DSC and XRD; and the microstructure changes with chemical composition of microregions were characterized through SEM-EDS. The thermochemical reaction characteristics for the roasting activation of tailings and sodium carbonate at different temperatures were as follows: at 450–650 °C, the ankerite, siderite and sulfide in tailings were oxidized and decomposed, while the crystal transformation of quartz and chlorite occurred; at 650–750 °C, quartz, muscovite and chlorite decomposed to form soluble sodium silicate, sodium aluminum silicate, diopside, sodium ferrite and copper ferrite etc; at 750–800 °C, due to the increase in products with low melting point, the roasted samples melted. During the roasting processes, the surface of minerals depressed and the structures were destroyed. These results can provide a theoretical foundation for thoroughly resource utilization of tailings.

Chemical and mineralogical properties of Guanajibo clay (Plinthic Kandiudults)

A profile of Guanajibo clay (Plinthic Kandiudults) was evaluated to determine the ironstone content in the horizons and its chemical, physical and mineralogical properties. The mineralogy was characterized by X-ray diffraction (XRD) and the iron and aluminum oxide content determined by selective dissolution, using citrate-bicarbonate dithionite (CBD) and ammonium oxalate (OX) extractions. Soil color and the color of ground ironstone were determined with Munsell color charts. Soil texture, pH, and effective cation exchange capacity (ECEC) were also evaluated. The highest content of ironstone per unit mass was found in the Ap horizon (4.6%), decreasing in the Bt (0.9%) and Btv1 (1.0%) horizons. An increase in ironstone content was observed in the Btv2 horizon (3.8%), which suggests that this horizon was formed from alluvial deposits containing ironstone. No ironstone was found in the Btv3 horizon. The texture of the Ap horizon was a sandy clay, and the other horizons had a clay texture. Clay content reached a maximum value of 92.8% in the Btv3. The ECEC was low for the whole profile, ranging from 2.37 cmolc/kg in the Ap horizon to 4.37 cmolc/kg in the Btv3 horizon. The low ECEC is indicative of mineralogy dominated by highly weathered clay minerals like kaolinite and iron and aluminum oxides. The XRD analysis confirmed the presence of kaolinite, goethite, quartz, hematite and gibbsite in the clay fraction (< 2 mm) of the soil. A small peak corresponding to 2:1 clay minerals, probably Al-hydroxy interlayer vermiculite or montmorillonite, was observed in clay samples from the Ap, Bt and Btv1 horizons. The major mineral components of the ironstone were goethite, kaolinite and quartz. The fine earth fraction (150 µm) of the Btv1 horizon had a 2.8% CBD extractable iron content and a ratio of OX/CBD less than 0.10, meeting the two requirements established by Soil Taxonomy to qualify as plinthic. The other horizons met the requirement of OX/CBD ratios of less than 0.10, but had less than 2.5% iron extractable by the CBD method. Soil management practices that prevent soil erosion must be implemented in this soil to ward off exposure of plinthite to the surface and its irreversible hardening to ironstone.

Two Processes of Anglesite Formation and a Model of Secondary Supergene Enrichment of Bi and Ag in Seafloor Hydrothermal Sulfide Deposits

The in situ element concentrations and the sulfur (S), and lead (Pb) isotopic compositions in anglesite were investigated for samples from seafloor hydrothermal fields in the Okinawa Trough (OT), Western Pacific. The anglesite grains are of two kinds: (1) low Pb/high S primary hydrothermal anglesite (PHA), which is formed by mixing of fluid and seawater, and (2) high Pb/low S secondary supergene anglesite (SSA), which is the product of low-temperature (<100 °C) alteration of galena in the seawater environment. The Ag and Bi in the SSA go through a second enrichment process during the formation of high Pb/low S anglesite by galena alteration, indicating that the SSA and galena, which may be the major minerals host for considerable quantities of Ag and Bi, are potentially Ag-Bi-enriched in the back-arc hydrothermal field. Moreover, REEs, S and Pb in the OT anglesite are likely to have been leached by fluids from local sub-seafloor volcanic rocks and/or sediments. A knowledge of the anglesite is useful for understanding the influence of volcanic rocks, sediments and altered subducted oceanic plate in hydrothermal systems, showing how trace metals behave during the formation of secondary minerals.

Mineral Content and Magnetic Properties of River Iron Sand from Jayapura, Papua

In this study, we investigated the mineral content and magnetic properties of river iron sand from Jayapura, Papua. The iron sand was collected from the Waimbow River in the Waibu District, whereas the bulk samples were extracted using a permanent magnet. The extracted iron sand was characterized using X-ray fluorescence and X-ray diffractometer to identify the elemental composition and structural phase. Meanwhile, the vibrating sample magnetometer was also applied to characterize the magnetic properties. The results show that the iron sand contains magnetite as a major mineral, with soft magnetic properties. The hysteresis curve shows that the iron sand has a high saturation magnetization of 27.8 emu/g, remanent magnetization of 2.34 emu/g, and coercive field of 21.3 Oe. These results also indicate that the iron sand formation in northern Papua was mainly due to lithogenic factors.

Assessment of Avroman Limestone Formation for Portland Cement Industry, Halabja Area, Kurdistan Region, NE-Iraq

Limestone is the main constituent of the raw materials used in manufacturing cement. In this study, the limestone deposits from the Avroman Formation are evaluated by using chemically and mineralogical techniques for their suitability to be used as a raw material for the cement industry. Twenty-one samples of limestone are collected from different beds of the Avroman Formation for petrographic study which shows that the limestone samples consist mainly of crystalline calcite. Physical and mechanical tests are performed in addition to the mineralogical and geochemical analysis using x-ray diffraction (XRD), x-ray fluorescence (XRF). Geological review and obtained results show that there is a good potential for industrial-grade limestone. The major clay minerals in the clay samples are chlorite, illite, montmorillonite, were as kaolinite appears as minor clay minerals. The geochemical analysis indicates that the limestone of Avroman formation has a wide range of CaO (46.13-56.00), Al2O3 (0.01-0.86), SiO2 (0.00-1.51), Fe2O3 (0.00-1.25), MgO (0.24-0.71), K2O, Na2O, TiO2, and MnO are traces. The physical properties (water absorption and moisture content) and chemical-mineralogical composition of the formation reflect that the dry process is preferable for the production of Portland cement. Mechanical analyses, especially compressive strength show that the quarrying and crushing will be competitive economically during manufacturing. From the results of the analyses, we conclude that the limestone of the formation and clay material of the study area are of good quality and fulfill the international standards of Portland cement.

Meteorite impact craters as hotspots for mineral resources and energy fuels: A global review

The ever-increasing recovery rate of natural resources from terrestrial impact craters over the last few decades across the globe offers new avenues for further exploration of mineral and hydrocarbon resources in such settings. As of today, 60 of the 208 terrestrial craters have been identified to host diverse resources such as hydrocarbons, metals and construction materials. The potential of craters as plausible resource contributors to the energy sector is therefore, worthy of consideration, as 42 (70%) of the 60 craters host energy resources such as oil, gas, coal, uranium, mercury, critical and major minerals as well as hydropower resources. Among others, 19 craters are of well-developed hydrocarbon reserves. Mineral deposits associated with craters are also classified similar to other mineral resources such as progenetic, syngenetic and epigenetic sources. Of these, the progenetic and syngenetic mineralization are confined to the early and late excavation stage of impact crater evolution, respectively, whereas epigenetic deposits are formed during and after the modification stage of crater formation. Thus, progenetic and syngenetic mineral deposits (like Fe, Ni, Pb, Zn and Cu) associated with craters are formed as a direct result of the impact event, whereas epigenetic deposits (e.g. hydrocarbon) are hosted by the impact structure and result from post-impact processes. In the progenetic and syngenetic deposits, the shock-wave induced fracturing and melting aid the formation of deposits, whereas in the epigenetic deposits, the highly fractured lithostratigraphic units of higher porosity and permeability, like the central elevated area (CEA) or the rim, act as traps. In this review, we provide a holistic view of the mineral and energy resources associated with impact craters, and use some of the remote sensing techniques to identify the mineral deposits as supplemented by a schematic model of the types of deposits formed during cratering process.

Nutritional Evaluation of Brillantaisia patula Leaves

Aim: To determine the nutritional and anti-nutritional compositions of Brillantaisia patula leaves using standard analytical methods.
 Place and Duration of Study: The proximate, mineral and anti-nutritional compositions were determined in the chemistry laboratory of Ekiti State University, Ado – Ekiti while the amino acid was determined at the Analytical Laboratory of Multi-Environmental Management Consultant, Lagos, Nigeria.
 Methodology: The proximate composition was carried out using the methods of Association of Official Chemists (AOAC) while mineral and anti-nutritional compositions were determined using standard analytical methods. Amino acid analysis was carried out through ion exchange chromatography (IEC) using the Technicon Sequential Multisample (TSM) Amino Acid Analyser.
 Results: The proximate composition ranged from 3.18% (crude fat) to 38.6% (carbohydrate). The major mineral constituents of the sample were: P (1061 mg/100g), K (874 mg/100g), Ca (799 mg/100g), Na (82.6 mg/100g) and Mg (24.3 mg/100g) while the minor mineral constituents were: Fe (26.9 mg/100g), Zn (7.7 mg/100g) and Mn (6.05 mg/100g). The evaluated anti-nutritional contents were: 6.71 mg/g oxalate, 5.37 % saponin, 1.0 mg/100g tannin and 4.72 mg/kg cyanide. Additional results showed that the leaves contained eighteen amino acids with values ranging from 0.504 g/100g cp (tryptophan) to 14.0 g/100g cp (glutamic acid). The value of the total essential amino acids (TEAA) with histidine was 45.6g/100g cp while the total non-essential amino acid (TNEAA) was evaluated to be 46.5 g/100g cp.
 Conclusion: Brillantaisia patula leaves could be utilized as a good source of essential amino acids and important mineral elements.

Mineralogical Characterization and Acid Pretreatment of a Gold Calcine Leach Residue

Miners around Zimbabwe used to supply gold concentrates from sulphide flotation to the Kwekwe Roasting Plant (Zimbabwe) for toll treatment. The concentrates were roasted in Edward’s roasters and the calcine product was leached by cyanidation. Due to inefficient roasting, overall gold recoveries of 75–80% left behind a rich calcine leach residue at the Kwekwe Roasting Plant. The characterization performed to establish a potential process route involved several techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), fire assaying and inductively coupled plasma (ICP). Assays conducted on samples from the 350,000 tons tailings dam residue, created over the operational years, gave an average Au grade of 8.58 g/t and 12.54 g/t for Ag. The base metals assayed—0.11% Cu, 0.10% Pb, 0.17% Zn and 26.05% Fe. SiO2 (36.1%), Fe2O3 (36.9%), Mg3Si4O10 (OH)2 (8.9%), NaAlSi3O8 (6.9%), and Fe3O4 (6.4%)—were the major mineral phases in the cyanide leach residue. SEM gold scans on 24 polished sections showed only 2 discrete gold particles of less than 5 µm, with one partially liberated and associated with quartz, while the other was fully liberated. Therefore, the particulate gold in the calcine leach residue was negligible. It was deduced from the analysis after ultrafine milling (P80 < 5 µm) followed by cyanidation that 68.53% of the gold was sub-microscopic. Direct cyanidation using bottle roll resulted in only 2.33% of the total gold being leachable, indicating that the calcine leach residue was highly refractory. Diagnostic leaching by sequential use of acids in order of their strength resulted in HCl leachable phases (CaCO3, CaMg(CO3)2, PbS, Fe1-XS, and Fe2O3) freeing 4.2% of the total Au during subsequent cyanidation leach. H2SO4 leachable phases (Cu–Zn sulphides, labile FeS2) released an additional 26.57% during cyanidation, whereas HNO3 leachable phases (FeS2, FeAsS) released a further 20.98% of Au. After acid treatment and subsequent cyanidation, hot caustic leach of the residue followed by carbon in pulp resulted 4.43% of the total gold being eluted. Therefore, 4.43% of the total gold was surface bound. From the analysis after diagnostic acid leaching, it was deduced that a total of 54.08% of the gold was in the acid-leachable phase. Due to cost and environmental considerations, H2SO4 was selected for the evaluation of acid digestion as a pretreatment stage followed by cyanidation. Increasing the H2SO4 strength for the pretreatment of the calcine leach residue increased gold recoveries during cyanidation.

Data-driven machine learning approach to predict mineralogy of organic-rich shales: An example from Qusaiba Shale, Rub’ al Khali Basin, Saudi Arabia

The Qusaiba Shale is a proven source rock for the Palaeozoic petroleum system of the middle east and it is targeted as a potential source of unconventional shale gas potential reservoirs in Saudi Arabia and recently considered a possible source of unconventional gas. Mineralogy of shale plays a key role in the successful design and performing the hydraulic fracturing operations and in turn evaluating the production potential. There is limited research available in the literature on the application of artificial intelligence for mineralogical prediction, which motivate us to perform this research on the Qusaiba Shale. The study aims to predict the Qusaiba Shale mineralogy, specifically clay and quartz minerals using readily available conventional logs, where both minerals are the major constituents of shale and help in assessing the brittle and ductile zones within the shale formation. Three lithofacies were defined in the Qusaiba Shale based on different geological and sedimentary features of core samples, and they have different ranges of quartz and clay content. Predictive models were developed for two utmost important minerals present in Qusaiba Shale formation including clay and quartz using artificial intelligence techniques. An adaptive neuro-fuzzy inference system (ANFIS) and artificial neural networks (ANN) were employed to precisely predict the two major minerals contents in Qusaiba Shale formation. All four models were found to have good accuracy. ANN-based models exhibited minimal errors with AAPE and RMSE of 2.53 and 1.45 for quartz and 3.43 and 2.01 for unseen data points for clay prediction models respectively. ANFIS-based prediction models presenting the AAPE and RMSE 2.67 and 1.83 for predicted quartz values and 3.59 and 1.89 for the clay content respectively. The applied artificial intelligence predictive model for major minerals in Qusaiba Shale i.e., clay and quartz would be a viable and useful approach to achieve valuable information about minerals content in shale for prospective evaluation of shale gas reservoirs. The results of this work would be useful in prospect evaluation and optimizing the production from unconventional shale gas reservoirs in Saudi Arabia. Moreover, the approach used may provide insights into replacing traditional mineralogy determination methods to save cost and resources in the absence of cores and mineralogy logs in the unconventional Qusaiba Shale resource. Furthermore, applying the same artificial intelligence approach and steps could be used for the field development of other shale gas and oil fields worldwide.

MANUFACTURING TECHNIQUE AND CONSERVATION TREATMENT OF A UNIQUE GILT-BRONZE STATUETTE EXCAVATED THROUGH RESTORATION OF THE STEP PYRAMID, SAQARA

Unexpected excavation of the Osirian statuette was inaugurated in 2021 during a conservation project at the first step in the western façade of King Djoser Pyramid which dates back to the Ptolemaic era. Varies strategies of the examination techniques, such as stereo and polarizing microscopes, and scanning electron microscopy coupled to energy dispersive X-ray spectrometry and X-ray diffraction were undertaken to characterize the chemical structure of gilt-layer, preparatory layer, and bronze alloy to evaluate their condition. This paper describes the actual condition of the statuette after excavation inside the King Djoser Pyramid, and characterization of the corrosion phases, and determines the best technique for conservation. Visual investigation revealed that the core of the bronze statuette was in good condition, but most gold with gesso was misplaced. Investigation and analyses results demonstrate that amazing technique which gilding has been accomplished as a thin layer over the white substrate from gesso. X-ray diffraction establishes that cuprite and atacamite resulting from the activation corrosion were the major minerals covering the statuette. Besides, calcite and gypsum were detected, which are to be a part of the preparatory layer. EDX results demonstrate that pure gold was likely used in the gilding layer. The gilt-bronze statuette was made of multi-layered surfaces. The solid cast was used in the crafting technique. Fixation of remaining plaster to metal was undertaken using Clucel G (4%). The figure was immediately treated via popular methods as mechanical tools and solvents. Benzotriazole inhibitor (3%) was used to cure the activation of bronze disease. The coating system was applied by using 3% paraloid B72. Finally, the statuette was preserved in the storage with the appropriate conditions.

The source, host minerals, and enrichment mechanism of lithium in the Xinmin bauxite deposit, northern Guizhou, China: Constraints from lithium isotopes

Most bauxites in China can be classified as the paleoweathering crust sedimentary type (PCS type) and are normally enriched with lithium (Li). However, the source, host minerals, and enrichment mechanism of Li in bauxites are poorly understood. This study takes the Xinmin bauxite deposit, a typical PCS type in northern Guizhou, China, as a case to trace the Li source and its enrichment using Li isotopes. The Xinmin bauxite deposit is a typical PCS type deposit with high Li contents (average = 756 × 10−6) and heavy Li isotopic compositions (δ7Li) (average = 0.83‰). The Hanjiadian Formation’s silty shale (S1–2hj) and the Huanglong Formation’s limestone (C2h) are the parent rocks of the Xinmin bauxite deposit. The Dazhuyuan Formation (P1d), as bauxite-bearing rocks of the Xinmin bauxite deposit, was formed via diagenesis from the parent rocks’ weathering products. According to the Li isotope fractionation mechanism under chemical weathering, the Dazhuyuan Formation (P1d) should have a lighter δ7Li than parent rocks. However, the δ7Li of the Dazhuyuan Formation (P1d) is heavier than that of parent rocks, indicating that the Dazhuyuan Formation’s original δ7Li was altered by adding external-source Li characterized by heavy δ7Li. Considering the sedimentary environment and Li isotopes, this study proposes that the Li carried by surface runoff characterized by heavy δ7Li is the main source of Li in the Xinmin bauxite deposit. The correlations between clay minerals vs. Li contents and δ7Li show that illite and kaolinite may be the major host minerals of Li in the Xinmin bauxite deposit. Furthermore, the positive correlations of Li vs. Na2O and MgO indicate that smectite is another possible Li host mineral. Combined with the formation process of a PCS type bauxite deposit, this study proposes that Li enrichment occurs during the primary bauxitic material formation stage. During this stage, the Li carried by surface runoff converged into the coastal restricted basin where the primary bauxitic materials were deposited. After small-scale transgression, retention water formed in the basin with the rise in the groundwater table. The retained water evaporated under a hot and dry climate, and Li carried by surface runoff accumulated in the basin and was finally adsorbed by clay minerals such as illite, kaolinite, and smectite in the primary bauxitic materials. This mechanism can significantly increase Li contents and δ7Li in the PCS type bauxite deposit. Additionally, this mechanism implies that the migration process of Li in surface runoff during the formation of primary bauxitic materials determined the present Li contents and δ7Li of a PCS type bauxite deposit, mainly controlled by the sedimentary environment and hydrologic and climatic conditions at that time.

Chemical, nutritional, and bioactive compositions of fresh, washed, and blanched shiitake

Washing and blanching are two important steps for the processing of fresh good grade small shiitake into casual snacks and prepared foods. This study explored their effects on the dimensions, weights, proximate compositions, taste and bioactive compounds of the shiitake caps and stipes. Results showed that the dimensions and weights of the caps and stipes increased after washing but decreased after blanching. On a dry basis, washing did not affect the nutrients and bioactive compounds contents of shiitake except sugars and polyols compared to fresh samples. However, blanching greatly reduced all the quality contents of the shiitake. The major minerals in the caps and stipes were potassium, magnesium and calcium. The main polyol, sugar, free amino acid, and 5'-nucleotide of shiitake were mannitol, trehalose, glutamine and 5'-adenosine monophosphate, respectively. Equivalent umami concentration (EUC) in the caps was three-fold higher than that in the stipes. Ergosterol, ergothioneine, γ-aminobutyric acid (GABA), and total phenols contents in the caps were significantly higher than those of the stipes, but the polysaccharides showed the reversed. Overall, both caps and stipes contain the necessary nutrients and bioactive compounds, and the blanching significantly affected the above-mentioned components of all tested samples.

Physicochemical Properties of Organophilic Clay Developed Using Hexadecyltrimethylammonium Chloride (HDTMAC) Modifier

Aims: Ogwuta clay from Unwana in the South Eastern part of Nigeria was modified by ion exchange reaction using hexadecyltrimethylammonium chloride (HDTMAC).
 Study Design: This study was analyzed experimentally and instrumentally.
 Place and Duration of Study: This study was carried out at the Department of Pure and Industrial Chemistry, Faculty of Science, University of Port Harcourt, Nigeria. The sample collection, literature search, experiment, results and analysis lasted for one and half years.
 Methodology: Physicochemical and thermal properties of the clay were determined after modification using classical and spectroscopic techniques. A combination of the wet and dry method (X-ray Fluorescence) was used to determine the metal oxide composition. Other techniques included; Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetry (TG). The Cation Exchange Capacity (CEC) was determined using the methylene blue method with a value of 16.4 meq/100g after modification.
 Results: The product was slightly acidic with pH 4.3. Silica (SiO2), alumina (Al2O3), Na+, and K+ were found to be 47.58 %, 18.99%, 2.27, and 0.23% respectively. The clay was limited in mineral impurities with 0.0% T4+, 0.41% Mg2+, and 0.11% Ca2+ but high in carbonaceous matter with loss on ignition (LOI) of 13.17%. A C-H asymmetric stretching was visible around the 2931.9 cm-1 region as revealed by the Fourier Transform Infra-Red analysis. The X-Ray Diffraction analysis of the modified clay showed a basal spacing of 8.121 Å. Also, the X-Ray Diffractogram revealed kaolinite as the major clay mineral with the presence of quartz and polygorskite.
 Conclusion: This study posits that the modified clay can be potentially suitable for the adsorptive removal of organic contaminants in aqueous and real life media.

Major Chemical Compounds and Mineral Elements of Astragalus membranaceus Cultivated on the Qinghai-Tibet Plateau with Different Planting Densities.

Astragalus membranaceus is a well-known herb that is widely used in the food and pharmaceutical industries. However, its commercial development has been limited due to wild resource shortages. This study was conducted in 2018 and 2019 to assess the effect of planting density on the major chemical compounds and mineral elements and biomass yield of A. membranaceus. The biomass yield (7,700.956 kg) reached the maximum at M2 planting density in 2018. In 2019, astragaloside IV reached its maximum concentration (0.117 %) at M2 group, which was significantly different from the concentrations obtained at the other groups. Calycosin-7-O-β-D-glucoside (0.062 %) reach its maximum concentration in 2019 at M5, but not significant with M2. The concentration of major chemical compounds among the five groups in 2018 and 2019 all conformed to the Chinese Pharmacopoeia standards. In 2018, the mineral elements (Al, Ba, Fe, Li and Mn) content was higher at M2 than other groups. However, a general decrease in the mineral elements content was observed at M2 group in 2019. Enrichment analysis demonstrated that the enrichment capacity was highest for phosphorus. In conclusion, according to the TOPSIS results, M2 planting density was recommended as the optimal application. For optimal economic benefits, A. membranaceus should be harvested when it is 2 years old.

Stochastic modeling and analysis of the bitcoin protocol in the presence of block communication delays

AbstractWe analyze the protocol of the bitcoin blockchain by using the PRISM probabilistic model checker. In particular, we (i) extend PRISM with the ledger data type, (ii) model the behavior of the key participants in the protocol—the miners—and (iii) describe the whole protocol as a parallel composition of processes. The probabilistic analysis of the model highlights how forks happen and how they depend on specific parameters of the protocol, such as the difficulty of the cryptopuzzle and the network communication delays. Our results confirm that considering transactions in blocks at depth larger than 5 as confirmed is reasonable because the majority of miners have consistent blockchains up‐to that depth with probability of almost 1. We also study the behavior of networks with churn miners, which may leave the network and rejoin afterwards, and with different topologies.

A Dusty Atmospheric River Brings Floods to the Middle East

AbstractTorrential rainfall and rapid snowmelt in April 2017 caused deadly floods in northwestern Iran. An atmospheric river (AR), propagating across the Middle East and North Africa, was found responsible for this extreme event. The snowmelt was triggered by precipitation and warm advection associated with the AR. Total satellite‐based rainfall for April 2017 was moderately below normal, suggesting that a heavy flood can happen during dry years. The AR was fed by moisture from the Mediterranean and Red Seas. Despite its adverse societal consequences, this event was beneficial to the recovery of the desiccating Lake Urmia. The impacts of this AR were not limited to flooding; it also facilitated dust transport to the region. This distinct characteristic of the ARs in the Middle East is attributed to major mineral dust sources located along their pathways. This event was reasonably predicted at 7‐day lead time, crucially important for successful early warning systems.

The Source Matters-Effects of High Phosphate Intake from Eight Different Sources in Dogs.

Simple SummaryThe vast majority of pet food products on the market contain the major mineral phosphorus in amounts exceeding the recommended daily allowance. A considerable amount of phosphorus in such products is highly water-soluble and bioavailable. Even though a sufficient supply of phosphorus is important for the body, an excessive intake can be harmful, especially in renal patients but also healthy individuals. This study investigated the effects of an excessive intake of organic phosphate sources (e.g., meat and bone meal) and inorganic phosphate salts compared with a balanced control diet without inorganic phosphates on factors of the body’s phosphorus regulatory system in healthy, adult beagle dogs. Most inorganic phosphates but not the organic phosphorus sources caused significant changes in these regulatory factors compared with the control diet. We conclude that the use of these inorganic phosphates in pet food is potentially harmful and should be restricted.Elevated serum phosphate concentrations are an established risk factor for cardiovascular disease and mortality in chronic kidney disease in various species. Independent associations of other parameters of phosphorus metabolism, such as phosphorus intake from different sources and serum concentrations of phosphorus, as well as parameters involved in the regulation, such as parathyroid hormone (PTH) or markers of bone turnover, have been studied in less detail. Therefore, the serum kinetics of phosphate, PTH, and the bone resorption marker bone-specific alkaline phosphatase (BAP) were investigated after 18 days of feeding a control diet and diets supplemented with eight different organic and inorganic phosphate sources aiming at 1.8% phosphorus per dry matter and calcium to phosphorus ratio between 1.3 and 1.7 to 1. Eight healthy beagle dogs (f/m, 2–4 years, 12.9 ± 1.4 kg body weight) were available for the trial. Highly significant differences in the serum kinetics of phosphorus, PTH, and BAP with the highest postprandial levels after feeding highly water-soluble sodium and potassium phosphates were found. We conclude that the use of certain inorganic phosphates in pet food is potentially harmful and should be restricted.

Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations.

Spodumene concentrate from the Pilbara region in Western Australia was characterized by X-ray diffraction (XRD), Scanning Electron Microscope Energy Dispersive Spectroscopy (SEM-EDS) and Mineral Liberation Analysis (MLA) to identify and quantify major minerals in the concentrate. Particle diameters ranged from 10 to 200 microns and the degree of liberation of major minerals was found to be more than 90%. The thermal behavior of spodumene and the concentration of its polymorphs were studied by heat treatments in the range of 900 to 1050 °C. All three polymorphs of the mineral (α, γ and β) were identified. Full transformation of the α-phase was achieved at 975 °C and 1000 °C after 240 and 60 min treatments, respectively. SEM images of thermally treated concentrate revealed fracturing of spodumene grains, producing minor cracks initially which became more prominent with increasing temperature. Material disintegration, melting and agglomeration with gangue minerals were also observed at higher temperatures. The metastable γ-phase achieved a peak concentration of 23% after 120 min at 975 °C. We suggest 1050 °C to be the threshold temperature for the process where even a short residence time causes appreciable transformation, however, 1000 °C may be the ideal temperature for processing the concentrate due to the degree of material disintegration and α-phase transformation observed. The application of a first-order kinetic model yields kinetic parameters which fit the experimental data well. The resultant apparent activation energies of 655 and 731 kJ mol−1 obtained for α- and γ-decay, respectively, confirm the strong temperature dependence for the spodumene polymorph transformations.

Petrology and geochemistry of metapelites from Asenitsa unit, Central Rhodope massif

Asenitsa unit metapelites (Central Rhodope massif) have a high variability in mineral, bulk chemical and trace element composition. Kyanite, staurolite and garnet are the major minerals in schists and show intensive retrograde change. Discrimination diagrams based on immobile trace elements indicate continental island arc or active margin setting of deposition.

Major Mineral Fraction and Physical Properties of Carbonated Peridotite (Listvenite) From ICDP Oman Drilling Project Hole BT1B Inferred From X‐Ray CT Core Images

AbstractWe quantified mineral proportions in listvenite (completely carbonated peridotite) in Hole BT1B drilled across the basal thrust of the Samail ophiolite by the International Continental Scientific Drilling Project Oman Drilling Project using 3D X‐ray Computed Tomography (XCT). We analyzed >250,000 XCT images from a continuous ∼200 m listvenite core. Histograms of the intensity of X‐ray attenuation of each XCT core‐slice image were fitted assuming that the listvenites are composed of magnesite, quartz, and dolomite. The XCT mineral peaks were confirmed by comparison with chemical mapping data obtained using an X‐ray fluorescence (XRF) core scanner. Listvenite matrix is composed almost entirely of magnesite and quartz, consistent with discrete XRD and XRF data. Veins are composed mostly of dolomite. The mean abundance of dolomite in listvenite from BT1B is 11 vol.%, whereas that in core sections within 15 m of the basal thrust is >50 vol.%, suggesting the basal thrust acted as a source of Ca‐ and CO2‐rich fluids. The SiO2:MgO:CaO molar ratio in the entire core from BT1B is 42:52:6, similar to that of onboard XRF data for discrete samples (41:54:5), whereas average Oman peridotites have ratios of (39:60:1), indicating Ca addition perhaps during carbonation. P‐ and S‐wave velocities and density of listvenite are close to those of peridotite and are higher than those of serpentinites. These results suggest that limited material transfer during carbonation and hydration of the Samail ophiolite, except for Ca, CO2, and H2O. Listvenites formed in the mantle wedge above subduction zones may be an overlooked reservoir for carbon in the Earth's interior.