The explorations of heat transport properties of minerals under extreme conditions are critical for understanding the formation and evolutionary processes of the Earth. Here, we perform systematic study on viscosities and thermal conductivities of diopside with different calcium contents under high temperature and high pressure through molecular dynamics simulations. The results demonstrate that both viscosities and thermal conductivities of diopside increase with rising pressure and decrease with increasing temperature. The effects of calcium content on the transport properties of diopside are distinct. Higher calcium content leads to the increase of viscosity and the reduction of thermal conductivity under extreme conditions. These behaviors are attributed to the larger ionic radii of Ca2+ions compared to other cations in diopside, which result in compressed local structures and enhanced interatomic interactions. These findings provide valuable insights into the transport properties, energy transformations, and lithospheric dynamics of silicate minerals under extreme conditions, and offer a deeper understanding of geophysical processes within Earth's interior.

Regulators specific adsorption mechanism underlying the selective flotation separation of pyrite from magnesium silicate minerals

Analysis of geochemical and mineral compositions of volcanic soil affected by Merapi eruption in Central Java Indonesia using laser-induced breakdown spectroscopy with calibration-free.

Synthesis of Methylated Silica from Mineral Silicate Raw Materials

Longmaxi shale is one of major and earliest shale gas formations in China, which hosts significant reserves and produces substantial amounts of natural gas. A thorough understanding of how mineral composition and geomechanical properties govern fracture initiation and propagation in the Longmaxi shale is therefore essential in designing hydraulic fracturing operations. In this study, nine core samples from different layers of the Longmaxi shale in Well A at Sichuan Basin were collected and a series of experiments were conducted, including X-ray diffraction, triaxial and uniaxial compression tests, brittleness index assessment, scanning electron microscopy, and nuclear magnetic resonance. Results reveal that samples from layers S6–S9 are rich in clay minerals, whereas layers S1–S5 are dominated by siliceous minerals. From the top to the bottom of the reservoir, a noticeable increase presents in total organic carbon (TOC), porosity, natural gas content, and silica mineral proportion. Young’s modulus shows a positive correlation with silicon mineral content but a negative correlation with clay content. Under high-stress conditions, shale with low quartz content tends to exhibit ductility, which inhibits fracture propagation. Quantitative models were established to predict brittleness and interpret the mechanical behavior of marine shale reservoirs.

Manganese nodules in the Clarion-Clipperton Fracture Zone (CCZ) of the eastern Pacific Ocean have been considered a target for the development of useful metal resources for more than half a century, due to the depletion of onshore resources and advances in mining technology, and are currently the closest to development. Because sediment surface disturbances and suspended plumes are expected to occur due to manganese nodule mining, characterizing sediments in exploitable areas as an environmental baseline is important to minimizing impacts on the marine environment. Here, we report on sediment properties in the Japanese exploration areas, DORD West Area and APEI-10, an area of particular environmental interest, in the western CCZ, where data are scarce compared with the eastern CCZ. We analyzed grain-size composition, chemical composition, and metals, including mercury, to a depth of 20 cm in the sediment. Based on the distribution patterns, metals were divided into group 1 (Mn, Ni, Cu, Zn, Cd, and rare earth elements), group 2 (Fe, Cr, As, and Pb), and group 3 (Hg), with each group observed to be affiliated with manganese oxides, silicate minerals, and organic materials, respectively. Mercury concentrations (<10 ng g−1 to 102 ng g−1) were comparable to those of deep basins; nevertheless, their fluxes were very low, reflecting the limited sedimentation of organic matter. The bulk compositions of the sediments from the western CCZ in this study were similar to those in the eastern-to-central CCZ, although the strong manganese concentrations in the topmost 10 cm of the eastern CCZ were not observed here. We suggest that during the last glacial period, when bottom-water dissolved oxygen concentrations were lower, the east–west gradient of surface primary production and organic matter flux was stronger than today, resulting in less extensive manganese reduction in surface sediments in the western CCZ.

The upstream areas of the two drinking water sources are located in the expansive soil development zone of central Anhui Province. This study focuses on investigating the spatial distribution characteristics of N, P, Fe, Mn and pH, in surface soil, deep soil, as well as upstream tributaries, reservoir water bodies, and surface sediments within the watershed of two drinking water sources. The research results showed that the surface soil has been severely acidified in upstream of two drinking water sources in Hefei, while the deeper soil is slightly alkaline. The long-term, excessive application of nitrogen and phosphorus fertilizers is the primary cause of surface soil acidification. Iron and manganese in alkaline environment readily form insoluble hydroxide precipitates that solidify in deep soil layers. Iron and manganese in acid environment readily undergo redox reactions to form divalent iron ions and manganese ions. The divalent iron ions and manganese ions enter water bodies through leaching and surface runoff. Long-term, heavy application of nitrogen fertilizer and phosphate fertilizers have resulted in N and P enrichment in the tillage layer. Under conditions of rainfall runoff and agricultural drainage, this accelerates N and P migration into water bodies. The chemical index of alteration (CIA) of the surface and deep soils in the study area are higher than 65, which indicates that the surface and deep soils in the study area are moderately weathered. Illite and vermiculite in the expansive soil are iron-bearing silicate minerals. Therefore, the iron of Illite and vermiculite silicate minerals have the possibility of entering the surface water bodies. The concentration of iron in the water body fulfills the conditions for succession from green algae to cyanobacteria. The two reservoirs and their tributaries are potentially at risk of eutrophication. In addition, Fe and Mn of the expansive soil of the containing iron and manganese films and iron-manganese nodules readily enter surface water bodies during the rainy season. In summary, the soils, water bodies, and sediments within drinking water source watersheds are an interconnected system. Studying the spatial distribution characteristics of N, P, Fe, Mn and pH is of important significance for developing precise measures to safeguard water quality in source watersheds. Therefore, the ecological measures should be taken to cover bare soil, such as the banks of river slopes are converted into ecological berms to reduce soil erosion. The organic agriculture should be promoted in the water protection zones to reduce the use of chemical fertilizers. It is necessary to strengthen the study of the release law of surface sediments from Dongpu and Dafangying Reservoirs. It will provide scientific data for the waterworks to take water from two reservoirs in a stratified manner. It is strictly prohibited to cause surface and deep soil to be exposed by extensive excavation in water source protection zones.

Compositions containing bitumen emulsions and solids have many applications, such as soil stabilization, cold mix asphalt preparation, dust binding, surface dressing and slurry sealing. Therefore, the interaction of bitumen with minerals is of great interest in science and applications. In the interaction of bitumen emulsion with a mineral surface, one of the processes that influence the properties of the bitumen-mineral composition is the formation of interface layers. Nuclear magnetic resonance can provide insights into the interactions of bitumen and minerals at the molecular level. However, the presence of magnetic constituents in most solids as well as the background magnetic field gradients at the interface does not allow the use of NMR to its full potential. In this work, we describe a 1H NMR approach to study the interface layer formed by a specified bitumen emulsion in the presence of non-magnetic as well as magnetic minerals. This approach is based on the consecutive flushing off of "bulky" components of the bitumen emulsion and the following extraction of the surface layer material, which can then be analyzed by NMR spectroscopy. As a proof of concept, this technique was tested on samples prepared using a bitumen emulsion and four different silicate minerals. The 1H NMR study showed that interfacial layers may accumulate asphaltenes adsorbed to mineral surfaces to a different extent depending on the specific elemental composition of minerals. More asphaltenes were detected in the interfacial layers on surfaces of studied minerals with a higher content of calcium.

The world's longest continuously operating Zn and Pb smelters were based in the Katowice-Szopienice area, for 180 years. In the current study, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD), and Atomic Absorption Spectroscopy (AAS) were used to examine recently collected topsoil samples from 0–10 cm depth. AAS studies revealed extremely high concentrations of heavy metals in the topsoil. Zinc, Pb, and Cd concentrations exceeded 10,000, 4,650 and 204 mg kg–1, respectively. The metals are mostly derived from sulphides, oxidized Zn-Pb ores, smelter slags, and emissions from metallurgical processes, such as metal alloy production. The abundance of each group of minerals depends on the type of industrial activity in the area (Zn or Pb metallurgy, metal rolling mills, smelter waste dumps, etc.). Sources of potentially toxic Pb, Cd, As and Sb are primary and secondary mineral assemblages. The largest part of Zn and Pb is bound in minerals that are products of base-metal ore weathering and in synthetic silicate minerals formed during Zn smelting. Smithsonite, hemimorphite and cerussite are among the most common secondary minerals. Metals from carbonate and silicate minerals are mobilized more slowly. Leaching tests showed that there is a risk of transfer of toxic Cd ions into soil solutions (>20% of Cd is present in the ion-exchange fraction). Our study will be useful for planning reclamation and revitalization efforts aimed at minimizing the adverse impact of metal-bearing minerals on the environment

Hydrogen cyanide,HCN, is a fundamental building block in astro-and cosmochemical environments, known for its ability to form prebioticallyrelevant molecules such as nucleobases. Although its polymerizationis inhibited under the cold, dilute conditions of the interstellarmedium, the higher temperatures of more evolved rocky bodies, combinedwith the presence of mineral surfaces, can catalyze the reaction.In this study, we use atomistic simulations grounded on the densityfunctional theory (DFT) to elucidate the complete tetramerizationpathway of HCN to diaminomaleonitrile (DAMN) and diaminofumaronitrile(DAFN), catalyzed by the crystalline Mg2SiO4 forsterite (120) surface. Results demonstrate that the intrinsicacid–base properties of the surface facilitate chemical bondformation/cleavage needed for HCN oligomerization, lowering activationbarriers by ∼120–220 kJ mol–1 withrespect to the gas-phase. Kinetic analyses reveal that the reactionsare feasible at temperatures above 300 K, particularly under conditionspresent in warm, rocky bodies such as asteroids, meteorites, and planetarysurfaces. The presence of water further accelerates key steps by assistingproton transfer processes. These findings support a model in whichMg-rich silicate minerals (abundant in the early Solar System) mayhave directly catalyzed the formation of complex organic molecules,which, in turn, are precursors of more complex biomolecules, therebycontributing to the essential chemical inventory for the emergenceof life on early Earth and other primitive planets with propitiousconditions.

Abstract The evolution and structure of sub-Neptunes may be strongly influenced by interactions between the outer gaseous envelope of the planet and a surface magma ocean. However, given the wide variety of permissible interior structures of these planets, it is unclear whether conditions at the envelope–mantle boundary will always permit a molten silicate layer or whether some sub-Neptunes might instead host a solid silicate surface. In this work, we use internal structure modeling to perform an extensive exploration of surface conditions within the sub-Neptune population across a range of bulk and atmospheric parameters. We find that a significant portion of the population may lack present-day magma oceans. In particular, planets with a high atmospheric mean molecular weight and large envelope mass fraction are likely to instead have a solid silicate surface, since the pressure at the envelope–mantle boundary is high enough that the silicates will be in solid postperovskite phase. This result is particularly relevant given recent inferences of high-mean molecular weight atmospheres from JWST observations of several sub-Neptunes. We apply this approach to a number of sub-Neptunes with existing or upcoming JWST observations and find that in almost all cases, a range of solutions exist that do not possess a present-day magma ocean. Our analysis provides critical context for interpreting sub-Neptunes and their atmospheres.

Abstract Enstatite chondrites (ECs) formed on at least two parent bodies, EH and EL. After the accretion of the EC parent bodies, EC material was subjected to varying degrees of parent body thermal metamorphism (measured by petrologic types 3–6), due to heat released by radioactive isotope decay. Current schemes to determine the petrologic type of the ECs are qualitative and ambiguous, and many studies have included known or misclassified shock‐melted ECs, which altogether have led to inconsistent classifications. In this study, we attempt to distinguish shock‐melted ECs from other ECs so that we can assess the effects of thermal metamorphism alone. We identified a suite of geochemical parameters that allow us to classify rapidly cooled, quenched shock‐melt ECs, including high‐Fe (Mg,Mn,Fe)S monosulfide, high‐Cr troilite, and high‐Ni kamacite. We then screened out shock‐melted samples. This then allowed us to establish a quantitative scheme to determine the petrologic type of an EC. This classification scheme is based on the petrography and geochemistry of glass, silicate minerals, sulfides, and metal. Specifically, for EH chondrites (which are similar but distinct from the EL group), among other parameters, the size and abundance of feldspar progressively increase from EH3 to EH6 (<13 μm, <8.5% modal% to >13 μm, 11.5 modal%), while the FeO content of enstatite changes from types 3–4 to types 5–6 (<0.45 wt% to >0.45 wt%). Additionally, we build on the work of others to propose a scheme that subdivides the EH3. Using the average Cr 2 O 3 content of olivine, we divide the EH3 and EH4 chondrites into EH3 Low (mean Cr 2 O 3 > 0.25 wt%) and EH3 High ‐EH4 subtypes (Cr 2 O 3 < 0.25 wt%).

Abstract The interface between the electrocatalyst and electrolyte is critical in seawater electrolysis for hydrogen production, yet optimizing interfacial H‐bond for enhanced catalytic activity and stability remains a significant challenge. This work demonstrates surface Lewis base (LB)‐mediated reconstruction of interfacial water H‐bond network within the electrochemical double layer toward enhanced seawater oxidation. The LB silicate species can be effectively immobilized on the surface of Ni(OH) 2 by electrochemical activation. In situ spectroscopy experiments show the LB‐induced reconstruction of the H‐bond network facilitates rapid OH − enrichment, reduces local acidity, and prevents surface Cl − corrosion on Ni(OH) 2 , significantly improving seawater oxidation activity and long‐term stability. Theoretical calculation further elucidates the key mechanism of the highly wettable silicate layers that can preferentially adsorb OH − while resisting Cl − . The optimized Ni(OH) 2 ‐Silicate achieves 121 mV reduction in overpotential at 200 mA cm −2 , stable operation for 620 h at industrial 1 A cm −2 , and robust activity for over 270 h at 1 A cm −2 in alkaline anion‐exchange membrane seawater electrolyzer. This LB‐induced strategy paves an avenue of regulating the interfacial microenvironment for durable chloride‐resisting electrocatalysis.

High sulfate solubility induced by silicate minerals: Implications for the formation of carbonatite-related rare earth element deposits

Achieving the thermal reinforcement between aluminum sensing elements and composites in induction welding via silane layers

Influences of hydrological and agricultural conditions on selenium distribution in groundwater: A case study in Sanjiang plain, Northeast China.

Selective separation of iron-bearing silicate minerals from hematite via a novel collector: surface interaction mechanistic investigation

Thermo-chemical coupled activation of multisource solid waste for silicon fertilizer preparation.

Remediation of asbestos with poplar and willow species and gene regulation network behind asbestos toxicity tolerance in trees.

The Ordos Basin is renowned for its development of continentaland transitional marine-continental shale formations, particularlywithin the Triassic Yanchang Formation’s Chang 7 member, whichfunctions as a primary stratum for shale oil reservoirs. These reservoirsare characterized by pronounced heterogeneity, posing substantialchallenges to their exploitation. In order to facilitate the assessmentand potential evaluation of these shale oil reservoirs during exploratoryphases, the present study concentrates on the Lower Triassic Chang7 shale located in the southwestern region of the Ordos Basin. Employinga diverse array of analytical techniquessuch as X-ray diffraction(XRD), total organic carbon (TOC) measurement, nitrogen adsorption(N2), high-pressure mercury intrusion (HPMI), microscopicthin sections, cast thin sections, and argon ion polished scanningelectron microscopythis research meticulously examines thereservoir spaces within silty shales. The lithological compositionis predominantly composed of siliceous minerals, with the reservoirspaces largely consisting of mineral matrix pores that include bothintergranular and intragranular porosity. The distribution of porevolume is primarily occupied by macropores and mesopores, while thestructure of these pores is significantly influenced by the TOC contentand the prevalence of siliceous minerals. The volumetric presenceand specific surface area of macropores and mesopores, alongside poreradius, demonstrate a negative correlation with TOC levels and a robustpositive correlation with felsic content, although they exhibit apronounced negative correlation with clay minerals. Conversely, thecorrelation with carbonate rock minerals appears to be negligible.Collectively, the pore structure is influenced by the content of organicmatter, felsic, and clay minerals, with felsic exerting the most substantialimpact. The research results indicate that pore development in theChang 7 Member shale reservoirs of the Longdong area is jointly controlledby mineral composition and the degree of OM evolution. This suggeststhat, in practical exploration, siliceous-rich, clay-poor silty shalesgenerally offer more favorable reservoir conditions. Conversely, intervalswith relatively high OM content that have not yet reached the hydrocarbongeneration threshold require integrated evaluation alongside theirthermal evolution stage to more accurately assess their reservoirpotential.