Search Results (33)

The aim of this work is to study the correlations of the elemental composition in the “soil–grape–wine” chain to determine the regional origin of Chardonnay grapes and wine. Soil samples (n = 40) from five vineyards in the Anapa region, Russia, taken from eight different depths, grapes from these vineyards (n = 75), and wines obtained from these grapes (n = 5) were analyzed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. The mineralogical composition of the soils was determined using thermal and X-ray phase analysis. The mineralogical composition of vineyard soils mainly consists of calcite, quartz, nontronite, vermiculite, and muscovite. According to spectrometric analysis, the distribution of both the total content and the mobile forms of elements in soil profiles turned out to be similar. The content of Na, Ca, and Sr increased with increasing sampling depth, while the content of Co, Cu, Fe, Ni, Mn, Pb, and Zn decreased. Regardless of the area of cultivation, the predominant elements in grapes are K, Ca, Na, and Mg. It is established that the elemental profiles of grapes and wine are correlated. At the same time, during the winemaking process, a decrease in the concentration of most elements (Al, Ba, Ca, Cu, K, Mg, Mn, Ni, Rb, Sr, Ti, and Zn) is observed. It has been shown that the vine is able to accumulate not only mobile but also less bioavailable forms of metals from the soil (Cu, Fe, K, Rb, Ti, and Zn), while the migration of Ca and Na remains low (<7%). Using discriminant analysis, a model of grape identification based on the concentrations of Al, Li, Mn, Na, Pb, and Rb was developed. This model demonstrated a high accuracy (100% for training and test datasets) in grape classification by region, confirming that the elemental “fingerprint” is a reliable marker of terroir. Full article

Yangjiatang Village traces its origins to the late Ming and early Qing dynasties. It has evolved over more than 400 years of history. There are 78 rammed-earth buildings left, making it one of the most complete and largest rammed-earth building complexes in East China. This study investigated the traditional rammed-earth houses in Yangjiatang Village, Songyang County, Zhejiang Province. By combining field investigation, microscopic characterization, and experimental simulation, we systematically revealed the erosion resistance of rammed earth in a subtropical humid climate was systematically revealed. Using a combination of advanced techniques including drone aerial photography, X-ray diffraction (XRD), microbial community analysis, scanning electron microscopy (SEM), and soil leaching simulations, we systematically revealed the anti-erosion mechanisms of rammed-earth surfaces in Yangjiatang Village. The study found that (1) rammed-earth walls are primarily composed of Quartz, Mullite, lepidocrocite, and Nontronite, with quartz and lepidocrocite being the dominant minerals across all orientations. (2) Regulating the community structure of specific functional microorganisms enhanced the erosion resistance of rammed-earth buildings. (3) The surface degradation of rammed-earth walls is mainly caused by four factors: structural cracks, surface erosion, biological erosion and roof damage. These factors work together to cause surface cracking and peeling (depth up to 3–5 cm). (4) This study indicates that the microbial communities in rammed-earth building walls show significant differences in various orientations. Microorganisms play a dual role in the preservation and deterioration of rammed-earth buildings: they can slow down weathering by forming protective biofilms or accelerating erosion through acid production. Full article

Clay minerals contain significant amounts of Fe in their alumosilicate framework, and this structural Fe can be reduced and re-oxidized, constituting a potentially renewable source of reduction equivalents in sedimentary environments. However, dissolution and/or clay mineral transformations during microbial Fe reduction contradict this concept. Here, we investigate how Fe reduction and re-oxidation affect the propensity of Fe to be released from the clay mineral structure and use selective sequential extractions in combination with Mössbauer spectroscopy. Negligible amounts of Fe were released in the sequential extraction of high Fe content clay minerals NAu-1 and NAu-2. Once aqueous Fe(II) was added as a reductant, the extraction procedure recovered the initially added Fe amount and up to 30% of the Fe from the clay mineral structure as both Fe(II) and Fe(III). Similar extents of Fe mobilization were found for clay minerals partly reduced (7%–20%) with dithionite, suggesting that mobilization was reduction-induced and independent of the source of reduction equivalents (Fe(II), dithionite). Although higher Fe reduction extents mobilized more structural Fe, i.e., >90% in fully reduced clay minerals, re-oxidation largely reverted the reduction-induced Fe mobilization in clay minerals. Our finding of reduction-driven Fe mobilization provides a plausible explanation for conflicting reports on Fe release from clay minerals and how extensive Fe atom exchange between aqueous and clay mineral Fe occurs. Full article

Cyanobacteria are a widespread group of photosynthesizing prokaryotes potentially relevant for space exploration, as they can produce both oxygen and organic matter. These organisms have been repeatedly proposed as tools for colonizing planetary bodies in the solar system. We used several Martian regolith simulants to support the growth of three widespread filamentous cyanobacteria (Desmonostoc muscorum UTAD N213, Anabaena cylindrica UTAD A212 and an uncharacterized Desmonostoc sp.). All cyanobacteria grew well on the surface of the commercial simulants MGS-1 and MMS-2 and in soluble extracts obtained from them, suggesting that these Martian regolith analogs contain everything necessary to sustain cyanobacterial growth, at least in the short term. We also evaluated the survival of the two Desmonostoc species under desiccation and UV-B radiation, using the same regolith simulants and two clays: Montmorillonite and nontronite. Desiccation hindered growth, but both cyanobacteria were able to recover in less than 30 days in all cases after desiccation. Short irradiation times (up to 1000 kJ/m²) did not consistently affect survival, but longer ones (24,000 kJ/m²) could fully sterilize some samples, although cyanobacteria within MGS-1, montmorillonite and nontronite showed signs of recovery in the long term (>70 days). Clays led to very fast recoveries, particularly montmorillonite. Full article

This article presents the results of laboratory studies on the smelting of nickel–chromium-containing ferroalloys from low-grade nickel ores from Kazakhstan. X-ray phase analysis was performed on raw materials, which included quartz, nontronite, chromium metahydroxide, goethite, magnetite, iron chromite, and nickel (II) silicate. The reduction reactions of metal oxides with carbon and carbon monoxide were studied as the temperature increased. Experimental smelting was carried out in a Tammann furnace at 1500–1550 °C using three types of reducing agent: RK coke, as well as its mixtures with low-ash Shubarkol coal, in ratios of 75:25 and 50:50. The second option demonstrated the highest economic efficiency, achieving a 91% nickel recovery rate, reduced coke consumption, and a slag-to-metal ratio of 3.07. Chemical analysis showed that the nickel content in the obtained alloys ranged from 2.5% to 6.5%, while chromium content ranged from 2.6% to 4.5%. X-ray phase analysis confirmed the presence of Fe₂Ni_0.6Si, Fe₅Si₃, and Fe₂CrSi phases in the alloy structure. Local element concentrations varied within the following ranges: Fe—55–59%, Ni—2–10%, Cr—2–7%, and Si—29–35%. The results of this study confirmed the feasibility of producing a nickel–chromium-containing alloy with a nickel content of 2–10% and a chromium content of 2–7%. Full article

The Biggenden gold-bearing Fe skarn deposit in southeast Queensland, Australia, is a calcic magnetite skarn that has been mined for Fe and gold (from the upper portion of the deposit). Skarn has replaced volcanic and sedimentary rocks of the Early Permian Gympie Group, which formed in different tectonic settings, including island arc, back arc, and mid-ocean ridge. This group has experienced a hornblende-hornfels grade of contact metamorphism due to the intrusion of the Late Triassic Degilbo Granite. The intrusion is a mildly oxidized I-type monzogranite that has geochemical characteristics intermediate between those of granitoids typically associated with Fe-Cu-Au and Sn-W-Mo skarn deposits. The skarn mineralogy indicates that there was an evolution from prograde to various retrograde assemblages. Prograde garnet (Adr_11-99Grs_1-78Alm_0-8Sps_0-11), clinopyroxene (Di_30-92Hd_7-65Jo_0-9), magnetite, and scapolite formed initially. Epidote and Cl-bearing amphibole (mainly ferropargasite) were the early retrograde minerals, followed by chlorite, calcite, actinolite, quartz, and sulfides. Late-stage retrograde reactions are indicated by the development of nontronite, calcite, and quartz. Gold is mainly associated with sulfide minerals in the retrograde sulfide stage. The fluids in equilibrium with the ore-stage calcites had δ¹³C and δ¹⁸O values that indicate deposition from magmatically derived fluids. The calculated δ¹⁸O values of the fluids in equilibrium with the skarn magnetite also suggest a magmatic origin. However, the fluids in equilibrium with epidote were a mixture of magmatic and meteoric water, and the fluids that deposited chlorite were at least partly meteoric. δD values for the retrograde amphibole and epidote fall within the common range for magmatic water. Late-stage chlorite was deposited from metasomatic fluids depleted in deuterium (D), implying a meteoric water origin. Sulfur isotopic compositions of the Biggenden sulfides are similar to other skarn deposits worldwide and indicate that sulfur was most probably derived from a magmatic source. Based on the strontium (⁸⁷Sr/⁸⁶Sr) and lead (²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb) isotope ratios, the volcanic and sedimentary rocks of the Gympie Group may have contributed part of the metals to the hydrothermal fluids. Lead isotope data are also consistent with a close age relationship between the mineralization at Biggenden and the crystallization of the Degilbo Granite. Microthermometric analysis indicates that there is an overall decrease in fluid temperature and salinity from the prograde skarn to retrograde alterations. Fluid inclusions in prograde skarn calcite and garnet yield homogenization temperatures of 500 to 600 °C and have salinities up to 45 equivalent wt % NaCl. Fluid inclusions in quartz and calcite from the retrograde sulfide-stage homogenized between 280 and 360 °C and have lower salinities (5–15 equivalent wt % NaCl). In a favored genetic model, hydrothermal fluids originated from the Degilbo Granite at depth and migrated through the shear zone, intrusive contact, and permeable Gympie Group rocks and leached extra Fe and Ca and deposited magnetite upon reaction with the adjacent marble and basalt. Full article

The peridotite massifs of New Caledonia are characterised by complex hydrodynamics influenced by intense inherited fracturing, uplift, and erosion. Following the formation of the erosion surfaces and alteration processes, these processes drive chemical redistribution during weathering; particularly lateritisation and saprolitisation. Magnesium, silica, and trace elements such as nickel and cobalt—released as the dissolution front advances—are redistributed through the system. New observations and interpretations reveal how lateritic paleo-land surfaces evolved, and their temporal relationship with alteration processes since the Oligocene. Considering the geometry of discontinuity networks ranging from micro-fractures to faults, the transfers occur in dual-permeability environments. Olivine dissolution rates are heterogeneously due to differential solution renewal caused by erosion and valley deepening. Differential mass transfer occurs between mobile regions of highly transmissive faults, while immobile areas correspond to the rock matrix and the secondary fracture network. The progression of alteration fronts controls the formation of boulders and the distribution of nickel across multiple scales. In the saprolite, nickel reprecipitates mostly in talc-like phases, as well as minor nontronite and goethite with partial diffusion in inherited serpentine. The current nickel distribution results from a complex interplay of climatic, hydrological and structural factors integrated into a model across different scales and times. Full article

The use of clays for thermal treatments and cosmetic purposes continues to be a worldwide practice, whether through the preservation of native cultural traditions, pharmaceutical formulations or integrative health and well-being practices. Special clays, such as bentonites, are very common for healing applications due to their high cation exchange capacity (CEC), high specific surface area (SSA) and alkaline pH values and, therefore, are used in multiple therapeutic and dermocosmetic treatments. Numerous bentonitic deposits occur on Porto Santo Island with different chemical weathering degrees. This research evaluates which residual soils have the most suitable characteristics for pelotherapy. The texture of residual soils varies from silt loam to loamy sand and SSA between 39 and 90 m²/g. The pH is alkaline (8.7 to 9.6), electrical conductivity ranges from 242 to 972 µS/cm, and CEC from 50.4 to 86.8 µS/cm. The residual soils have a siliciclastic composition (41.36 to 54.02% SiO₂), between 12.52 and 17.65% Al₂O₃ and between 52 and 82% smectite content, which are montmorillonite and nontronite. Specific heat capacity (0.5–0.9 J/g°C) and cooling kinetics (14.5–19 min) show that one residual soil has the potential to be suitable for pelotherapy according to the literature. Moreover, the residual soils have As, Cd, Co, Cr, Hg, Mn, Ni, Pb, Sb and V concentrations higher than the limits of guidelines for cosmetics and pharmaceutical products. Full article

The article presents the results of obtaining a composite material by sintering nickel-containing raw materials mixed with carbon-containing materials, namely using coke and semi-coke. The sintering process was performed at a charge layer height of 240 mm and the temperature of the lower layer was T = 1200 °C. The results of the sieve analysis showed (a fraction of 10 mm) that the yield of a suitable composite material using coke was 68.3% and with semi-coke 67.0%. The average nickel and chromium content in the composite materials was 1.42% and 3.07%, accordingly. As a result of determining the strength characteristics of the obtained composite materials with various reducing agents by dropping from a height of 2 m onto a steel pallet, it was found that the obtained composite materials have high mechanical properties in terms of strength of 81% and 89.2%. The results of the elemental composition at the studied points and the thermal analysis of the studied composite material are presented. The mineralogical composition of the composite material is presented in the form of serpentine and nontronite, and the empty rock is made of quartz and talc. The activation energy of thermal analysis by the method of non-isothermal kinetics were calculated. The results of experiments on the production of composite materials from nickel-containing raw materials will be recommended for obtaining the optimal composition of composite materials at the stage of pilot tests and industrial development of the developed technology for processing nickel ores of the Republic of Kazakhstan. For the processing of nickel-poor nickel ores, it is of great importance to obtain optimal technological and technical and economic indicators that ensure low cost of nickel in the resulting product. Full article

Clay minerals have a great influence on the resulting properties of ceramic bodies. Fly ash as a waste material from burning black coal in power plants is a potentially valuable source of oxides (Al₂O₃, SiO₂ or Fe₂O₃) for this production. Considering the process of ceramic firing, it is important to understand the thermal behavior of individual ingredients. The thermal behavior of natural smectite minerals (montmorillonite, beidellite, hectorite and nontronite) and their mixtures with added fly ash at different ratios (10%, 30% and 50%) was investigated. The phase analysis was obtained using X-ray diffraction and FT-IR spectroscopy. Under heating to 1200 °C, the structural changes of smectites were divided into four steps including dehydration, dehydroxylation, decomposition and crystallization of new phases. The addition of fly ash caused a shift in the reaction temperatures for all the mentioned phases. These changes were most noticeable for mixtures with hectorite; on the contrary, they were least noticeable for beidellite mixtures. Total mixture mass loss continually decreased with increasing fly ash amount. The obtained experimental thermal data can be applicable not only in the production of ceramic bodies or energy waste processing but also in construction and ensuring the safety of municipal waste landfills. Full article

Rhenium (Re) is an extremely rare element, with a crustal abundance of approximately 0.4 parts per billion (ppb) and a sea water concentration of 8.3 parts per trillion (ppt). However, Re concentrations in anoxic marine sediments range from 2 to 184 ppb, which is attributed to reduction of the highly soluble perrhenate ion (Re(VII)O₄⁻) to insoluble Re(IV) species. Anoxic sediments typically contain Fe(II) and sulfide species, which could potentially reduce Re(VII) to Re(IV). In this study, we examined the interactions of KReO₄ with magnetite (Fe₃O₄), siderite (FeCO₃), vivianite (Fe₃(PO₄)₂•8H₂O), green rust (mixed Fe(II)/Fe(III) layered double hydroxide), mackinawite (FeS), and chemically reduced nontronite (NAu-1) using X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy to determine the valence state and speciation of Re. Uptake of Re by green rust was rapid, with ~50% associated with the solids within 2 days. In contrast, there was <10% uptake by the other Fe(II) phases over 48 days. Reduction of Re(VII) to Re(IV) was only observed in the presence of green rust, producing clusters of bidentate-coordinated Re(IV)O₆ octahedra.. These results suggest that except for green rust, the potential for other Fe(II)-bearing minerals to act as reductants for ReO₄⁻ in sedimentary environments requires further investigation. Full article

This research delves into the vital aspect of adapting local soil properties for 3D printing and explores the mix design of collected earthen materials to tackle challenges in printability, shrinkage, and mechanical properties. Initially, soil samples from six local sites underwent characterization based on Atterberg’s limits, focusing on identifying the most suitable high-clay-content soil. The soil with a higher clay content was used for further study, and its clay type was determined using an X-ray diffraction (XRD) analysis, revealing the presence of 49% kaolinite, 15% nontronite, and 36% illite clay minerals. Four earthen mixes were designed by including stabilizers (i.e., hydrated lime), natural pozzolana, and degradable natural fibers (wheat straw fiber). Subsequently, the study examined their rheological properties, shrinkage behavior, compressive and flexural strength, and printability (including extrudability and buildability). The pure soil mixture excelled in printing quality and mechanical strength, but suffered from cracking and drying shrinkage due to its high nontronite clay content. The existence of 15% nontronite clay mineral in the soil resulted in significant shrinkage and extensive cracking of specimens. However, fiber incorporation effectively mitigated large cracks and reduced shrinkage to as low as 2.6%. Despite initial expectations, introducing lime and pozzolana as soil stabilizers did not improve strength, prevent shrinkage, or improve the printability of soil mixes. Full article

The research of organoclays has been occurring for many years to develop and add value to these inorganic materials for several industrial applications, such as pollutant absorbers or impermeable plastics. The organoclay applications are intrinsically related to organo-modification and the structure of clays. This study shows the preparation and characterization of organoclays produced by a nontronite type clay (calcic bentonite) from the Tosagua Formation in the peninsula of Santa Elena in Ecuador. These clays were purified and centrifuged before organo-treatment. The purification and separation processes were used to remove organic matter and carbonates, and a cationic interchange from calcic to sodic (Ca²⁺ to Na⁺) was carried out. Organo-modification was performed using two types of cationic compounds, i.e., Oleylmethylbis (2-hydroxyethyl) ammonium chloride and Di (hydrogenated tallow alkyl) quaternary amine to organoclay with different surface hydrophobicity. The samples were characterized by X-ray diffractometry (XRD), infrared spectrometry (FT-IR), thermo-gravimetry (TGA), and scanning electron microscopy (SEM) to analyze the effect after the mentioned treatment and the resulting organoclays by the addition of these surfactants. The results confirm the significant intercalation of the organic treatment suitable for environmental remediation, compatibilizing recycled plastics, or improving performance in different hydrophobicity systems for industrial applications. Full article

The southern island of the Philippines is abundant in silicate minerals, including the province of Lanao del Norte. However, some of these resources in the region are untapped for use as raw materials in the production of various ceramic products for industrial, pharmaceutical, and nanotechnology applications. These could include tiles, sanitary ware, dinnerware, insulating bricks, porcelain, membranes and coatings. Some of the explored minerals are the red clay in the municipality of Linamon, diatomaceous earth in Kapatagan and black cinder in Salvador. It is the aim of this study that these minerals are evaluated in terms of their physical and chemical properties so that these will be used for optimum application. The properties that were determined were their specific gravities, raw and fired surface colors, Atterberg limits, particle size distribution, thermal properties, morphologies and mineralogical compositions. Pellets were formed for each raw material and fired at two temperature levels 1000 °C and 1200 °C to evaluate their physical properties. Linamon red clay has a 38.88% cumulative passing size of 150 µm, and the black cinder of Salvador and diatomaceous earth of Kapatagan have cumulative passing sizes of 96.53% and 60.12% at 150-micron sieve, respectively. The common mineral contents of the three samples are montmorillonite, quartz and andesine. Black cinder fired at 1200 °C has the darkest shade of red with a greasy quasi-submetallic luster. It attained the highest fusion coverage on the platform among the three materials, which makes it a potential supplement or replacement for feldspar in clay-based triaxial materials for ceramic production. The diatomaceous earth has the potential to be a secondary clay content source and a good source of flux for a certain temperature range. Both the red clay and diatomaceous earth were classified as plastic materials that are suitable for brick production, and the red clay is also feasible for pottery production. These are a few of the features of the clay minerals in the region that present suitable properties for application as raw materials in the production of ceramic tiles and hollow ceramic products. Full article

Glaucony occurrences have been reported both from exposed transgressive and overlying highstand system tracts. However, its occurrences within highstand deposits are often invoked as the result of underlying condensed section reworking. Detailed textural, mineralogical and geochemical reports of glaucony grains in highstand deposits remain elusive. The northern Gulf of Cadiz shelf (SW Iberia) offers a unique opportunity to investigate late Holocene glaucony authigenesis in a well-documented time-stratigraphic context, where transgressive deposits are locally exposed on the seafloor and are laterally draped by highstand muddy deposits. In this study, glaucony grains extracted from a core retrieved from a highstand muddy depocenter off the Guadiana River were investigated by means of digital microscopy, X-ray diffraction (XRD), and electron microscopic methods (FESEM-EDX and TEM-HRTEM). To better constrain the glaucony origin (autochthonous vs. allochthonous) in highstand muddy deposits, glaucony grains from surficial samples—taken from exposed transgressive deposits—were also investigated. Glauconitization in the studied core can be largely attributed to the replacement of faecal pellets from c. ~4.2–1.0 cal. ka BP. Both XRD and TEM-HRTEM analyses indicate that glaucony consists mainly of an R1, with a minor presence of R0, smectite-rich (nontronite) glauconite-smectite mixed-layer silicate, made up of 35–75% glauconitic layers and 65–25% of interstratified smectite layers. At the mineral lattice level, minor individual 7Å layers (berthierine) were also identified by HRTEM. Shallow radial cracks at the pellet surface, along with globular and vermiform-like biomorphic to low packing density lamellar-flaky nanostructures, mineralogical properties, and K-poor content (average 0.4 atoms p.f.u.) indicate a scarcely mature glauconitization process, attesting to formation of the grains in situ (autochthonous). Glaucony grains from exposed transgressive deposits, i.e., in the tests of calcareous benthic foraminifera, do not share a genetic relationship with the grains investigated in the highstand deposits, thus supporting the autochthonous origin of glaucony within the highstand deposits. Our combined dataset provides evidence of a multiphase history for autochthonous glaucony formation in the Guadiana shelf, as its genesis is traced to both transgressive and highstand conditions. While eustatic sea-level changes favoured glaucony formation under transgressive conditions, factors such as protracted low sediment supply and the establishment of a strong nutrient-rich upwelling system in the study area promoted glaucony development during late Holocene highstand conditions. Full article