Amount Of SiO2 Research Articles

Petrogenesis of the Late Carboniferous Trondhjemite in Central Inner Mongolia in North China and Constraints of Intra-Oceanic Subduction in the Southern Paleo-Asian Ocean

Intra-oceanic subduction is a fundamental process on Earth, the study of which can improve the understanding of plate tectonic processes and the history of continental growth. Here, we report on newly recognized trondhjemite in the north of Diyanmiao ophiolite belt in North China. The trondhjemite was found along the Erenhot-Hegenshan suture zone. U-Pb zircon dating revealed that the trondhjemite crystallized at 309 ± 2.1 Ma. The trondhjemite had a high amount of SiO2 (68.94–76.45 wt %), Al2O3 (13.37–15.90 wt %), and Sr (232–601 ppm); and a low amount of K2O (1.57–2.70 wt %), Y (6.91–9.39 ppm), Ni (1.10–4.19 ppm), and Cr (1.55–13.50 ppm). The Na2O/K2O ratios were 1.90–4.37. There was a lack of negative Eu anomalies. It was relatively enriched in large-ion lithophile elements (LILEs) such as Rb, Ba, K, and Sr; was depleted in high-field-strength elements (HFSEs) such as Nb, Ta, Ti, and P; and had low total rare-earth element (REE) contents (27.73–49.63 ppm) with distinct REE fractionation (chondrite-normalized (La/Yb)N of 5.76–10.52), which was similar to adakitic rocks formed by partial melting of subducted oceanic crust. The trondhjemite, together with Diyanmiao ophiolite (335.6 Ma), may have formed during the stages of intra-oceanic subduction, suggesting that in the Early Carboniferous–Late Carboniferous, the southern Paleo-Asian Ocean was in its subduction stage.

Performance Research and Formulation Optimization of High-Performance Local Insulation Spray Coating Materials.

Bird pest control has become a major task for the operation and maintenance of distribution network lines. Epoxy resin that cures quickly at room temperature can be used to coat locations where birds frequently build their nests. However, epoxy resin has enormous internal stress and is brittle, so it is essential to toughen it. In this paper, for a room temperature curing system composed of polyurethane-modified epoxy resin and a polythiol curing agent, three kinds of particles, i.e., Al2O3, SiO2, and Mg(OH)2, were used to modify a polyurethane modified epoxy resin. Orthogonal experiments were designed to study the effects of different fillers on the comprehensive properties of polyurethane-modified epoxy resins. The experimental results showed that there were not only independent effects of different kinds if particles on the resin, but also synergistic effects of multiple particles. Nanoparticles can reduce the defects introduced by microparticles to a certain extent and improve the mechanical and electrical properties of the resin. The overall performance of the resin was optimized when the amounts of SiO2, Al2O3, and Mg(OH)2 were 1.7%, 2.5%, and 7%, respectively. The tensile strength of the resin was increased by 70%, the elongation at a break by 67.53%, and the breakdown strength by 20.31% compared with before the addition of filler. The microscopic morphology and thermal properties of the resin before and after the addition of filler were also studied. Adding fillers caused more cracks to absorb part of the energy when the resin matrix was stressed and increased the rigidity of the resin matrix and the resin’s glass transition temperature (Tg) by 13.48 °C. Still, the temperature corresponding to the maximum rate of weight loss (Tmax) remained unchanged.

Solvothermal Prepared Slag Nanocomposite as a Catalyst for Organic Dye Photodegradation

Steel slag nanocomposite was synthesized in this study using a solvothermal preparation technique from raw electric arc furnace (EAF) slag. XRF, SEM, FTIR, and UV–Vis spectroscopy techniques were used to characterize the prepared nanocomposite. The XRF result shows a high amount of SiO2 and Fe2O3 constituent in the slag with a small weight percentage of TiO2. The prepared slag nanocomposite was utilized for methylene blue (MB) dye degradation. The Photodegradation result from the study indicated an optimum degradation efficiency of 77.07 % at a 40 min irradiation time. The effect of pH variation and catalyst dosage on photodegradation was studied. The results reveal that photodegradation of the dye occurs best in an alkaline solution and that increasing the catalyst dosage above the reaction threshold reduces the degradation efficiency.

Sawdust Recycling in the Development of Permeable Clay Paving Bricks: Optimizing Mixing Ratio and Particle Size

The permeable pavement system (PPS) has effectively contributed to stormwater management as a low-impact development (LID) technology. The suitability of clay bricks, consolidated with waste materials, for sustainable PPS applications in urban infrastructure needs further attention. In this study, several series of permeable clay paving bricks samples were prepared by mixing different ratios and particle sizes of sawdust (SD) with clay soil and firing at 900 °C. The raw soil and SD samples were characterized through sieve analysis, X-ray Fluorescence (XRF), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FTIR). The bricks were tested for their compressive strength, bulk density, apparent porosity, water adsorption, permeability coefficient, and stormwater treatment efficiency. The clay soil comprised 17.5% clay/silt with appropriate amounts of SiO2 (50.47%), Al2O3 (19.14%), and fluxing agents (15.34%) and was suitable for brick manufacturing. XRD and FTIR analysis revealed that the soil predominantly comprises quartz, dolomite calcite, feldspar, kaolinite, illite, and chlorites. The SD samples were enriched with amorphous and crystalline cellulose. The compressive strength of the bricks decreased, while the permeability of the bricks increased with an increasing percentage of SD. An optimal percentage of 10% SD achieved a 21.2 MPa compressive strength and a 0.0556 m/s permeability coefficient, meeting the ASTM specifications for PPS. The optimal size of SD, between 0.5 and 1.0 mm, achieved the desired compressive strength of the bricks. The permeable bricks effectively removed the total suspended solids (TSS), turbidity, and BOD5 from the stormwater, which complies with the guidelines for wastewater reuse applications.

Assessment on Optimal Level of Reactive Biosilica Affected by Incineration Conditions in Perlis Rice Husk Ash as Supplementary Cementitious Materials in Concrete

Rice husk (RH) is an agricultural waste transformed to produce secondary by-products and is widely accepted as a substitution of cement or concrete mixtures. This paper deals with the optimal level of SiO2 content due to various incineration conditions of rice husk grown in Perlis, Malaysia. RH was burnt in a controlled environment with a targeted temperature of 650, 750 and 850 °C at various incineration period between 1 and 6 h. All the ashes were assessed for visual inspection and physiochemical and mineralogical properties using X-ray fluorescence (XRF) and X-ray diffraction (XRD). From the analysis, a significant amount of SiO2 in the range of 89–93 wt % was successfully obtained with the preferable properties of supplementary cementitious materials: amorphous silica with high reactivity, ultrafine size, and large surface area. Contrary, the burning temperature of 850 °C greater than 4 h incineration period is not advisable to be used as it transformed into a crystalline phase. No obvious color changes were observed for the ashes as the amount oxide compound of K2O causes carbon entrapped in surface melting. To sum up, 650 °C incineration for 1 h shows an optimum result, and the RH is bearable to reduce the negative impact on the environment.

Silica nanoparticles derived from Arundo donax L. ash composite with Titanium dioxide nanoparticles as an efficient nanocomposite for photocatalytic degradation dye

Water pollution is a serious problem that threatens both developed and developing countries. Several methods have been used to purify contaminated water, among which the photocatalytic decomposition approach is widely used to purify contaminated water from organic pollutants. In this work, biomass derived SiO2 nanoparticles composite with TiO2 semiconductors used as an efficient photocatalyst for degradation of RhB dye molecules under UV−visible light irradiation is proclaimed. The different weight percentages of Arundo donax L. ash-derived SiO2 nanoparticles combined with TiO2 nanoparticles were prepared through the wet impregnation method. The photocatalytic degradation ability of the as-prepared samples has been scrutinized against the degradation of Rh B dye in which the pronounced photocatalytic degradation efficiency 93.7% is successfully achieved on 50 wt % SiO2-50 wt % TiO2 nanocomposite photocatalyst. The catalytic performance of the nanocomposite decreases with an increase of 50%–75% in SiO2 nanoparticles. There could have been a decrease in degradation efficiency due to an excess amount of SiO2 covering TiO2 nanoparticles, which prevented photons from reaching the nanoparticles. The efficiency of cyclic decomposition of the 50 wt% SiO2-50 wt% TiO2 composite showed only a slight change in photocatalytic capacity compared to the first cycle, which ensures the durability of the sample. However, the hydroxyl radical species play the main role in the degradation process, which has been confirmed by the scavenger test. The probable reaction mechanism is also deliberated in detail. The high photocatalytic performance of novel eco-friendly SiO2-TiO2 photocatalyst make it ideal for water purification applications.

High efficient and clean utilization of coal for the carbothermic reduction of silica

In order to alleviate the problems of large amount of reducing agent, low output and high energy consumption in the production process of industrial silicon, TGA, SEM, XRD, Raman spectroscopy and other methods were used to study the properties of carbonaceous materials prepared from distiller’s grains (DG) and soft coal (SC) in the ratio of 20:80 and 50:50, and their effects on the reaction behavior of silica reduction process. The results showed that sorghum distillers’ grains (S-DG) had a strengthening effect when mixed with SC at a 20% mixing ratio, and Tmax and activation energy are reduced. Corn distillers’ grains (C-DG) inhibit the graphitization of SC to a greater extent and produce amorphous carbon structures. Through the silica carbothermal reduction experiment, it was found that there are a large number of SiC diffraction peaks in the S-DG and a small amount of SiO2, but there is basically no SiO2 in the C-DG. This shows that in the process of carbothermic reduction, silica first reacts in large quantities to form SiC, so the reduction effect of C-DG on silica is better.

Kaman (Kırşehir-Türkiye) floritlerinin mineralojik ve gemolojik özellikleri

Fluorites are found in the region between Hamit, Karakütük, Bayındır and Yeniyapan villages of the Kaman District (Kırşehir-Türkiye). Fluorites are located in altered levels due to faults in quartz syenites containing gray-pink colored K-feldspar, plagioclase and quartz, amphibole and biotite type mafic minerals in the Upper Cretaceous aged. Central Anatolian Granitoids, Fluorites observed in purple and green in places, pink, yellow, white colors as veins reaching from a few centimeters to two meters, purple and green in places, pink, yellow, white colors.
 According to X-Ray diffraction (XRD) analysis results, quartz syenites are composed of quartz, feldspar and clay minerals; fluorites are composed of fluorite and quartz mineral combination. According to Wavelength Dispersive XRF (WDXRF) analysis results, it is observed that the amount of F in purple fluorites is 39.8%, the amount of CaO is 51.2%, the amount of SiO2 is 8.68%, the amount of F in green fluorites is 46.7%, the amount of CaO is 51.5%, and the amount of SiO2 is 1.15%. As a result of cathodoluminescence analysis, the presence of rare earth elements (REE) terbium (Tb), erbium (Er), dysprosium (Dy) and samarium (Sm) elements were observed in fluorites.
 In order for the fluorites in the region to be used as a gemstone; while features color variety, texture, and easy workability are revealed as positive features, features such as low hardness, low strength in atmospheric conditions, and cleaved structure in coarse crystals are determined as negative features. For this reason, the fluorites in the region can be used as gemstones, however it is important that they undergo improvement methods (saturation with epoxy).

Design and preparation of a novel organic–inorganic hybrid for reducing fire hazards of epoxy

AbstractHerein, a novel type of organic–inorganic hybrid (SiO2‐Co‐BHMTPMPA) with core‐shell structure was designed to reduce the fire risk of epoxy resin (EP). The chemical composition and micro‐morphology of SiO2‐Co‐BHMTPMPA were characterized by XRD, FTIR, TGA, XPS, and SEM. As observed by SEM images, the SiO2‐Co‐BHMTPMPA exhibited spherical morphology while a large amount of SiO2 was attached on the surface to form a covering layer. The SiO2‐Co‐BHMTPMPA hybrids showed better dispersion state within epoxy matrix, in comparison with that of Co‐BHMTPMPA. According to TGA and cone calorimeter test, the thermal stability and fire safety of EP/SiO2‐Co‐BHMTPMPA have been significantly improved. Compared to neat epoxy, the epoxy composites with 2 wt% SiO2‐Co‐BHMTPMPA exhibited a low mass loss rate, increased residual char of 68.4%, reduced 36.0% in peak heat release rate (PHRR) and a drop of 28.5% in peak smoke production rate (PSPR), respectively. The good dispersibility, catalytic carbon formation and smoke inhibition ability of SiO2‐Co‐BHMTPMPA hybrid led to the reduction of fire risk of epoxy composites.

An interfacial study between SrZr0.85Cu0.15O3-δ and barium oxide-containing borosilicate glass sealant for solid oxide fuel cell application

The broad and widespread commercialisation of solid oxide fuel cells still requires a lot of research and development. Since the fuel cell consists of several components, compatibility of these components is necessary. Because structural, thermal or chemical changes in any of the cell components affect the overall working of the cell. In the present work, perovskite structured SrZr0.85Cu0.15O3-δ (cathode) and a glass sealant, 45SiO2–40BaO–10B2O3–5ZrO2, are mixed in the ratio of 70:30 wt %, respectively and heat-treated at 800 °C for 1, 10, 100 and 500 h in the air. The X-ray diffraction results show the presence of some minor amounts of detrimental phases, i.e. BaSrSi2O6 and SiO2. However, the presence of these phases is minute compared to the major crystalline phase (SrZrO3). Grain size increases with increasing heat-treatment duration with a well-connected cathode-sealant interface. The coefficient of thermal expansion is in the required range as prescribed for solid oxide fuel cells even after 500 h of heat treatment of the diffusion couple at 800 °C.

The anti-corrosion performance of reinforcement behaviour of silica from different sources in bio-based paints

PurposeThe aim of this study is to investigate the usability of horsetail, sunflower stalk, wheat stalk and corn stalk ashes as additives in paints and their performance against corrosion resistance when used.Design/methodology/approachThe ashes of horsetail, sunflower stalk, wheat stalk and corn stalk were investigated in this study in single, binary and ternary combinations with three different percentages as additives in paints. Samples of concrete with any combinations of ashes resisted against the corrosion of steel reinforcements, but horsetail ash proved to be the most effective.FindingsIt can be said that these research results show that the paint containing horsetail ash is an excellent coating material that can be used in paints for the corrosion resistance of steel in reinforced concrete. The corrosion rate decreased with the increase in the amount of reactive SiO2. There was less mass loss with the formation of resistance against corrosion in the horsetail ash added concretes. That is why horsetail ash is one of the most effective options for the aforementioned purpose.Originality/valueBeing cheap and easily obtainable, the materials used for coating in this study are perfect candidates for industrial use.

Ultra-selective microfiltration SiO2/carbon membranes for emulsified oil-water separation

Microfiltration SiO2/carbon membranes were fabricated by compositing SiO2 microspheres into carbon membrane matrix through facile blending, shaping and pyrolysis. The chemical groups, thermal stability, pore structure, microstructure, morphology, mechanical strength and surface hydrophilicity of the membranes were characterized by the technologies of Fourier-transform infrared spectroscopy, thermogravimetry, bubble pressure method, X-ray diffraction, Scanning/Transmission electron microscope, compressive stress and water/oil contact angle, respectively. The effect of SiO2 amount on the structure and separation performance of the membranes for the purification of oil-water emulsion was investigated. The results showed that the incorporation of SiO2 microspheres improved the surface hydrophilicity/oleophobicity, matrix density, oil removal and anti-fouling ability of carbon membranes. The highest oil removal is up to 99.99%, along with the water permeation flux of 5550 kg·m−2 h−1 MPa−1 for resultant carbon membranes made by the precursor containing 8 wt% SiO2 microspheres. The present work offers an easy approach for preparing microfiltration carbon membranes with highly efficient removal of oil from wastewater.

Stability of a Mixed‐Valence Hydrous Iron‐Rich Oxide: Implications for Water Storage and Dynamics in the Deep Lower Mantle

AbstractIncorporation of water into mantle compositions can have significant effects on the phase relations in the systems. In this study, we synthesized an iron‐rich hexagonal hydrous phase (referred to as “HH1‐phase”) under the high pressure‐temperature (P‐T) conditions of the deep lower mantle and determined the crystal structure of the HH1‐phase at 79 GPa using the multigrain crystallography method. The chemical formula obtained was Fe12.76O18Hx (x ∼ 4.5) in the Fe‐O‐H system. To demonstrate the role of HH1‐phase for water storage in multicomponent systems relevant to mantle compositions, we investigated the stability of HH1‐phase in both MgO‐rich pyrolitic and SiO2‐rich basaltic compositions. Our results indicate that the HH1‐phase serves as major water storage in a pyrolitic composition, whereas the Al‐rich CaCl2‐type δ‐phase and SiO2 phase are major water storage phases in a SiO2‐rich basaltic composition. Incorporation of considerable amounts of SiO2, MgO, and Al2O3 into the HH1‐phase expands its stability field from 98 GPa in the Fe‐Al‐O‐H system to at least 108 GPa (corresponding to ∼2,400 km depth) in the Mg‐Si‐Al‐Fe‐O‐H system. Plumes of hot upwelling rock rooted at the base of the lower mantle have been proposed as a possible origin of hotspot volcanoes. The hydrous Fe‐rich HH1‐phase, if included into the material of upwelling plumes, will decompose on its rising to the upper part of the lower mantle and release water. Our results should provide constraints on water storage in the deep lower mantle and have implications for deep mantle dynamics.

Oxidation behaviour of interlocking SiC–Si coating for graphite prepared by preoxidation and gaseous silicon infiltration process

An interlocking SiC–Si coating on graphite was fabricated by a method combining preoxidation and gaseous silicon infiltration processes. The effect of preoxidation time on the microstructures and oxidation behaviour of the coating was investigated. After preoxidation of graphite at 900 °C for 10 min, the thickness of the as-obtained SiC–Si coating increased from 35 μm to 80 μm, and the penetration depth of the SiC–Si phase was up to several hundred microns. The isothermal oxidation test at 1500 °C suggested that the mass loss of coated graphite decreased from 5.42% after 6 h to 1.28% after 110 h, and the 15 times thermal shock test between 1500 °C and room temperature suggested that the mass loss decreased from 13.20% to −0.34% because of preoxidation. The improved oxidation performance is ascribed to the fact that the interlocking structure of the SiC–Si coating alleviates crack propagation during oxidation, and a large amount of glassy SiO2 produced on the thick SiC–Si layer migrates and seals the defects in the coating. It is believed that the construction of an interlocking structure offers a technological basis to produce oxidation protective coatings for carbon-based materials in high-temperature applications.

Effect of carbon nanotubes on the microstructure and properties of plasma electrolytic oxidized ceramic coatings on high silicon aluminum alloy

Ceramic coatings with carbon nanotubes were prepared on high silicon aluminum alloy by plasma electrolytic oxidation. The microstructure, phase, and elemental compositions of the matrix and ceramic coatings were characterized by metallographic microscope, X-ray diffraction, field emission scanning electron microscope, micro confocal Raman spectrometer and energy dispersive spectrometer. The functional groups contained in the coating were characterized using Fourier infrared spectrometer and X-ray photoelectron spectroscopy. The electrochemical workstation and thermal conductivity meter were employed to study the corrosion resistance and thermal conductivity of ceramic coatings. The effect of CNTs on the morphology, microstructure, coating formation and growth, corrosion resistance and thermal conductivity of PEO coatings on ADC12 Al alloy was investigated. The results showed that the micropores on the surface of the PEO coating can be used as discharge channels for various migrating ions and particle groups in the electrolyte to participate in the formation and inward and outward growth of the coatings. CNTs participated in the formation and growth of ceramic coating by surface adsorption, melt wrapping and fusion reaction during the plasma electrolytic oxidation process. The coating contains mainly α-Al2O3, γ-Al2O3, SiO2 and small amount of SiC phases. The changes of electrochemical corrosion and thermal conductivity of the PEO coatings are related to the regulation of the coating microstructure by CNTs.

Complementary evaluation of potential barriers in semiconducting barium titanate by electrostatic force microscopy and capacitance–voltage measurements

Electrostatic force microscopy (EFM) was used to directly image the impact of SiO2 content variations on the grain boundary potential barriers in semiconducting BaTiO3-based ceramics. The grain boundary barriers were shown to be significantly thinner and more pronounced as the amount of SiO2 was increased from 0 to 5 mol%. The EFM results were confirmed by capacitance–voltage (C–V) measurements which proofs the accuracy of both methods and highlights their importance for gaining a better understanding of the interrelations between material composition and electrical properties.

Resource Assessment and Possible Industrial Applications of Bauxite Occurrences in Parts of the Mambila Plateau, NE Nigeria

Bauxites are normally formed from underlying aluminosilicate rocks as a result of tropical weathering. In our previous 2 papers, we presented the Geology, possible host, mineralogy, and geochemistry of the bauxites of Mambila Plateau, NE Nigeria. The bauxite was formed from residual chemical weathering of trachyte and occurs as a blanket cover over saprolite. XRD results showed gibbsite as the major mineral with small amounts of hematite, kaolinite, and quartz. Geochemistry of the bauxite ore is characterized by enriched Al2O3 (39.50-78.20.0%), erratic amounts of SiO2 (2.89-5.13%) and Fe2O3 (5.98-21.96%). In this study, the resources of Mambilla Bauxite Deposits (Block I and Block II) have been estimated to be 7,529,312.5 metric tons using block method of vertical geological cross-section bearing in mind that the Mambilla Bauxite Deposits have been explored by pitting on a regular grid pattern of 100 m×100 m. The bauxite deposit in Block II has met the requirement for metallurgical grade bauxite as standard specification (IS: 5953-1985, Reaffirmed [1]). While, Block I deposit has not met such specifications. Sustained investment in bauxite exploration is required to upgrade the ore reserves for sustainable development of a mining enterprise.

Preparation of Waterproof and Air-Permeable Membrane by Water Surface Spreading Method for Metal-Air Battery

The electrochemical performance of metal–air batteries is sensitive to environmental humidity, which significantly limits its wide application in an air environment. In this paper, a waterproof and breathable polydimethylsiloxane (PDMS) composite membrane has been successfully synthesized by the water spreading method for metal–air batteries. The effects of spreading times and fillers (hydrophobic SiO2 and silicalite-1) on the water vapor and air permeability of the PDMS membrane were investigated. The results demonstrate that increasing the spreading times and adding an appropriate amount of hydrophobic SiO2 can improve the waterproof quality and air permeability of the PDMS membrane. The optimized membrane was assembled into a metal–air battery, and the effects of the membrane on the running resistance, cycle number, and polarization voltage of the battery were evaluated. The hydrophobic SiO2–PDMS membrane significantly reduces the running resistance of the battery and improves the cycle number of lithium–air batteries by 25% and that of zinc–air batteries by 100% in an air environment (40% RH, 25 °C). The polarization voltage is also significantly reduced, indicating great potential in applications.

Elevated Temperature Deformation of P/M Dispersion - Strengthened Copper and Aluminium

Abstract Paper deals with the low cost route of the preparation of SiC/Si3N4 nanocomposite. It is shown that SiC nanoinclusions distributed within the Si3N4 matrix can be produced by carbothermal reduction of fine SiO2 particles added into a starting mixture. The amount of SiC nanoinclusions can be adjusted by the appropriate amount of SiO2 + C additives. Almost full density of the final composite was achieved by hot-pressing at 1750 °C using a “special” heating regime allowing the outgasing of CO as a product of carbothermal reduction.

SiC–Si3N4Nanocomposite Prepared by the Addition of SiO2+ C

AbstractPaper deals with the low cost route of the preparation of SiC/Si3N4nanocomposite. It is shown that SiC nanoinclusions distributed within the Si3N4matrix can be produced by carbothermal reduction of fine SiO2particles added into a starting mixture. The amount of SiC nanoinclusions can be adjusted by the appropriate amount of SiO2+ C additives. Almost full density of the final composite was achieved by hot-pressing at 1750 °C using a “special” heating regime allowing the outgasing of CO as a product of carbothermal reduction.