Natural Quartz Research Articles

Controllable preparation and multifunctional application of high-strength porous anorthite ceramics

Porous anorthite ceramics, as emerging green materials, garner significant interest in applications such as catalyst carriers, thermal insulation, and sound absorption due to their distinctive structural and functional attributes. In the present study, porous ceramics with anorthite as the main phase were prepared using the natural minerals kaolin, calcite, and quartz as raw materials, combined with a simple and environmentally friendly foam gel-casting method. By adjusting the additive content, we optimized the viscosity and stability of the slurry, and further investigated the impact of the slurry's foaming capacity on the resulting porosity, pore size, mechanical strength, and other key properties of the ceramics. Notably, the porous anorthite ceramic with 15 g/L of foaming agent demonstrated a porosity of 70.57%, a bulk density of 0.81 g/cm3, and a thermal conductivity of 0.26 W/(mK), along with a commendable compressive strength of 8.85 MPa due to the homogeneous sub-spherical pore structure and plate-like anorthite grains. The suitability of these porous ceramics for catalyst carrier applications was confirmed through the effective photodegradation of a methyl orange solution.

Preparation and characterization of quartz ceramic proppant replacing natural quartz sand by solid waste silica fume

AbstractThe improper disposal of industrial wastes will cause environmental pollution and economic losses due to the loss of active ingredients. Solid waste silica fume and pyrolusite powder were used to synthesize quartz ceramic proppant by pelleting and sintering to replace natural quartz sand for unconventional oil and gas exploitation. The effects of pyrolusite powder content and sintering temperature on the apparent density, breakage ratio, and acid solubility of the proppant were thoroughly studied. The phase composition and microstructure of the proppant were characterized by X‐ray diffraction and scanning electron microscopy, respectively. The results revealed that the main crystal phase of the proppant prepared without pyrolusite was cristobalite, while that with pyrolusite was cristobalite and quartz, and the content of quartz phase increased gradually with increasing the pyrolusite content. The addition of pyrolusite remarkably increased the density and improved the performance of the proppant due to the resulting glass phase at high temperatures and the presence of andradite. As adding 20% pyrolusite, the apparent density of the proppant sintered at 900°C was 2.26 g/cm3, while the breakage ratio under 28 MPa closed pressure and acid solubility reached the minimum, 9.89% and 5.3%, respectively, meeting the industrial standard requirements.

Influence of water on crystallographic preferred orientation patterns in a naturally deformed quartzite

Abstract. Laboratory experiments demonstrate that intragranular water exerts an important control on deformation within quartz, causing weakening and promoting plasticity. The role of water in natural quartz deformation, however, remains unclear, as recent studies find an inverse relationship between water content and the magnitude of plastic strain. Furthermore, little work has investigated the effects, if any, of water on the relative activity of various slip systems in quartz. We focus on a naturally strained quartzite from the Antietam Formation of the Blue Ridge in Virginia, USA. Quartz water content ranges from < 50 to > 2000 ppm H2O. Water content and crystallographic data were correlated for 968 grains, enabling us to explore the relationship between water content and quartz crystallographic preferred orientation (CPO) patterns. “Dry” (< 150 ppm H2O) and “wet” (> 500 ppm H2O) subsets show distinct CPOs; c axes of dry grains define a cross girdle oriented perpendicular to the extension direction (x), whereas c axes of wet grains are concentrated along the perimeter of the pole figure. All water content subsets show grains clustered near the direction of maximum shortening (z), consistent with activity of the basal 〈a〉 slip system. The cross girdle in the driest grains suggests activity of prism 〈a〉 and possibly rhomb 〈a〉, whereas the orientation of the wettest grains implies a contribution from prism [c] slip. These slip system interpretations are supported by analyses of intragranular misorientations. These results indicate that water content impacts the relative activity of various slip systems in natural quartz, potentially affecting application of the quartz opening angle thermometer.

Microbiological indicators of the biofilms microparticles of quartz sand and polypropylene after short-term exposure in soil

The purpose of this study was to investigate dynamics of biofilm biomass on microparticles of natural material quartz sand and the artificial material polypropylene (plastisphere) as well as change in biofilm-forming microorganisms’ number under a short-term in situ field study. In this study microparticles of polypropylene and quartz sand ranging in size from 3 to 5 mm were used. The total microbial count and the number of sulfate-reducing bacteria in the biofilm (by traditional culture-based microbiological methods) and the biofilm biomass (by the method with the crystal violet) were investigated. According to the determined microbiological indicators, over time (90 days) on the polypropylene it was observed decreasing of both the number of studied groups of microorganisms and the formation of a microbial biofilm, compared to the quartz sand. Determination of microbiological indicators of the materials surface allows understanding the aspects of their preservation/removal from the environment and requires additional research.

Fate and transport of fragmented and spherical microplastics in saturated gravel and quartz sand.

Microplastics in urban runoff undergo rapid fragmentation and accumulate in the soil, potentially endangering shallow groundwater. To improve the understanding of microplastic transport in groundwater, column experiments were performed to compare the transport behavior of fragmented microplastics (FMPs ∼1-µm diameter) and spherical microplastics (SMPs ∼1-, 10-, and 20-µm diameter) in natural gravel (medium and fine) and quartz sand (coarse and medium). Polystyrene microspheres were physically abraded with glass beads to mimic the rapid fragmentation process. The experiments were conducted at a constant flow rate of 1.50 m day-1 by injecting two pore volumes of SMPs and FMPs. Key findings indicate that SMPs showed higher breakthrough, compared to FMPs in natural gravel, possibly due to size exclusion of the larger SMPs. Interestingly, FMPs exhibited higher breakthrough in quartz sand, likely due to tumbling and their tendency to align with flow paths, while both sizes (larger and smaller relative to FMPs) of SMPs exhibited higher removal in quartz sand. Therefore, an effect due to shape and size was observed.

The Strong Thermally and Optically Stimulated Luminescence of Solonópole (Ceará, Brazil) Natural Quartz: Comparing Records and Proposing New Insights

The Strong Thermally and Optically Stimulated Luminescence of Solonópole (Ceará, Brazil) Natural Quartz: Comparing Records and Proposing New Insights

Development and characterization of PVA-based nanocomposites with graphene and natural quartz nanoparticles for energy storage applications

This study presents the development and characterization of polymer nanocomposites (PNCs) using polyvinyl alcohol (PVA) as a matrix, incorporating graphene (Gr) and natural quartz nanoparticles (NQNs) as nanofillers. The graphene content was fixed at 1 wt%, while the quartz content was varied at 3 wt%, 7 wt%, and 11 wt%. The NQNs were derived from natural quartz rocks, which were ground and milled to nanosize, emphasizing the utilization of natural materials. Comprehensive characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), and extensive electrical and dielectric measurements. SEM and EDS analyses revealed the nearly spherical shape of the NQNs, with sizes ranging from 25 to 88 nm and an average size of 61.2 ± 13.1 nm. XRD patterns indicated a decrease in crystallinity of the polymer matrix with increasing NQNs content, with the PVA/Gr-11 wt% NQNs showing nearly amorphous characteristics. FTIR spectra demonstrated the incorporation of NQNs within the PVA matrix, affecting the chemical bonding and reducing the intensity of characteristic peaks. UV–Vis spectra indicated a significant decrease in the optical bandgap with the addition of NQNs, suggesting enhanced electronic properties. The electrical conductivity measurements, at a frequency range of 50 Hz to 8 MHz and temperature range from 20 °C to 80 °C, showed that the incorporation of Gr, a two-dimensional (2D) material, and NQNs significantly enhanced the conductivity of the nanocomposites, with the optimal performance observed at 7 wt% NQNs. Dielectric measurements revealed that the PVA/Gr-7 wt% NQNs nanocomposite exhibited superior dielectric properties, with higher dielectric constant and lower dielectric loss compared to pure PVA. Nyquist plots indicated reduced bulk resistance and enhanced thermal stability for the PVA/Gr-7 wt% NQNs composite. Capacitance-frequency and conductance-frequency analyses of the fabricated capacitor confirmed this composite's superior performance for dielectric capacitors. The optimized PVA/Gr-7 wt% NQNs nanocomposite, leveraging the unique properties of natural quartz and 2D graphene, demonstrated significant improvements in electrical and dielectric properties, making it a promising candidate for advanced dielectric capacitors in energy storage applications. The study confirms the innovative use of natural and 2D materials to develop energy storage devices.

Comparison of TL characteristics of natural quartz and zircon.

The dosimetry of different minerals is carried out to investigate the dose received by the population in case of a nuclear accident. Retrospective dosimetry is a field where there is a continuous search to find new materials. Beach sand minerals, namely quartz and zircon, were exposed to beta and gamma radiation and studied separately. A comparison of the thermoluminescence (TL) output of different peaks of quartz for beta and gamma was studied. Comparison of quartz peaks with the TL output of zircon peaks was carried out. TL output for a constant dose of gamma is always higher compared to the TL output received due to beta.

Geochemical reactions initiated by subglacial abrasion of natural quartz and alkali feldspar

Geochemical reactions initiated by subglacial abrasion of natural quartz and alkali feldspar

Deconvolution and Growth curve for Thermoluminescence glow curves

In this work, a new program is presented that, in addition to performing the deconvolution of Thermoluminescence glow curves, allows the user to store multiple deconvolution data. This data is stored in an internal database, which allows the fitted parameters to be compared. After these deconvolutions, the program allows the user to summarize the values of the selected parameters. These values can be fitted with some of the available functions to observe the behavior of each parameter for each isolated peak. The program was tested with data from the GLOCANIN project to observe the accuracy of the deconvolution in synthetic and real samples with different number of peaks. Natural quartz grains obtained from sediments and irradiated with different doses were used for the Growth curves. After deconvolution, five peaks were identified, which showed different behaviors; these new data were fitted with different functions using the same program.

Energy-saving technology of silicate pressed material with use of micro-porous silica-earth raw materials

Purpose. Research on the possibility of producing a silicate material that hardens under reduced parameters of autoclave processing, due to the introduction of natural zeolite into the raw material mixture. The methods. To solve the problems set in the work, following methods were used:generalization and analysis of theoretical and experimental data of domestic and foreign authors; analytical studies of raw materials (chemical, mechanical and physical-mechanical methods); laboratory experiment using physical and mechanical tests. The study of the properties of raw materials was carried out according to standardized methods. Findings. It has been proven that natural zeolite is an effective component of silicate pressed materials for reducing heat energy consumption during their autoclaving. It was established that with a low zeolite content, the compressive strength of lime-zeolite stone practically does not differ from the strength of limestone-sandstone. A study of the influence of the autoclave treatment regime on the strength of silicate pressed concrete, which was made using a lime-zeolite binder, was carried out. It has been experimentally confirmed that the strength-to-strength ratio of pressed silicate material on a lime-zeolite binder (compared to a similar pressed silicate material on a lime-sand binder) depends to a lesser extent on the water vapor pressure during autoclaving. The originality. The dependences of the compressive strength limit of samples-beams made of lime-zeolite binder at different mass ratios of lime:siliceous component, as well as the dependence of the compressive strength limit of silicate pressed materials on a lime-zeolite binder on water vapor pressure during autoclave processing. Practical implementation. The results of the research can be used at enterprises of the building materials industry in the production of silicate bricks. Replacing natural quartz sand with natural zeolite reduces the production cost of lime-zeolite binder, and the reduction of water vapor pressure during autoclaving of silicate pressed material on lime-zeolite binder reduces the consumption of high-value natural gas.

Influence of Different Types of Surfactants on the Flotation of Natural Quartz by Dodecylamine.

The synergistic effect among flotation agents is why combined flotation agents exhibit superior performance compared to single flotation agents. This research investigates the influence of three surfactants with different charges of polar groups, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and octanol, combined with dodecylamine (DDA), on quartz flotation. Through the implementation of flotation tests, bubble-particle adhesion induction time testing, gas-liquid two-phase foam properties testing, and surface tension testing, it is revealed that substituting part of the DDA with these surfactants can either enhance or at least maintain the quartz recovery, affect the adhesion induction time, reduce the surface tension of the flotation system, and change the foaming performance and foam stability, depending on their mole ratio in the combined collector. Compared to DDA alone, combining CTAB or OCT with DDA can significantly increase quartz recovery, while SDS with DDA only yields an approximate recovery. Combining SDS or OCT with DDA can reduce the foam stability, while CTAB with DDA enhances the foam stability. The effect of the combination of surfactants and DDA on the adhesion induction time of quartz grains of different sizes with bubbles is the same; furthermore, there is a negative correlation between the adhesion induction time and the recovery, while the foaming properties and stability of foam are positively correlated with the recovery.

Silane Gas Production Through Hydrolysis of Magnesium Silicide by Hydrochloric Acid

Monosilane (SiH4) is a common precursor for the production of high-purity silicon for solar PV applications. As an alternative to carbothermic reduction of silica to produce metallurgical grade silicon with subsequent conversion to silane, an alternative route over magnesiothermic reduction of silica to Mg2Si has been explored in our earlier work. In the current work, silane gas production through hydrolysis of Mg2Si in HCl acid solution was studied. Two sources of Mg2Si were chosen: a commercial Mg2Si source and a Mg2Si source produced through magnesiothermic reduction of high-purity natural quartz. Effects of various parameters on the hydrolysis of Mg2Si, including different experimental setups, temperature of the acid solution, acid concentration, reaction time, and relative amounts of reactants were studied. The evolution of produced gases was determined by two different methods: firstly, by passing the produced gas through a KOH solution to capture Si with subsequent analysis of the Si content in the KOH solution by inductively coupled plasma mass spectrometry and secondly, on-line gas analysis by GC–MS. The silane distribution between different silane species with reaction time was evaluated and the activation energy of silane formation was calculated. The results indicated comparable silane yields obtained from the on-line GC–MS method and KOH solution analysis method, as well as for commercial Mg2Si and the Mg2Si–MgO mixture produced through magnesiothermic reduction. Furthermore, adding HCl acid to Mg2Si in water led to higher SiH4 formation yield than adding Mg2Si to acid. However, the total silane yield for the two methods was similar at approximately 32%.Graphical

Effect of alpha irradiation on the saturation characteristics of fine-grained quartz OSL

A negative relationship has been reported for the characteristic saturation dose (D0) of the quartz optically stimulated luminescence (OSL) signal and the quartz grain size, of which the mechanism is still not understood. Here, the natural coarse-grained quartz samples (63–90 μm, 90–125 μm) are artificially ground into fine grains and the effect of alpha irradiation on the D0 values of the ground fine grains is investigated. The ground fine grains (4–11, 11–45, 45–63 μm) have similar D0 values as the coarse grains. Laboratory alpha irradiation is administered on the artificial 4–11 μm quartz fraction. The D0 shows an increasing trend with the amount of alpha irradiation; meanwhile, the proportion of the fast OSL component decreases and the proportions of the medium and slow components increase with alpha irradiation. The higher D0 after alpha irradiation may be a result of the higher proportion of electron traps related to the medium component. However, the increasing trend of D0 stops when the alpha dose reaches a certain amount, and the degree of D0 increase induced by alpha irradiation cannot fully account for the much higher D0 values of the fine quartz grains in nature.

High-Temperature Reactive Wetting of Natural Quartz by Liquid Magnesium.

High-temperature wetting of natural, high-purity quartz (SiO2) and liquid magnesium (Mg) was investigated at temperatures between 973 and 1273 K. Sessile drop experiments using the capillary purification (CP) procedure were carried out under an Ar gas atmosphere (N6.0), eliminating the native oxide layer on the surface of Mg melt. The results showed that the wetting behavior was strongly dependent on temperature. At 973 and 1073 K, the wetting system displayed relatively large contact angles of 90° and 65°, respectively, demonstrating modest wetting. The wetting increased to some extent by increasing the temperature to 1123 K with a wetting angle of 22°. However, the SiO2/Mg system demonstrated complete wetting at temperatures of 1173 K and above. Furthermore, interface microstructure examination showed different reaction product phases/microstructures, depending on the wetting experiment temperature.

The 450 nm (2.8 eV) cathodoluminescence emission in quartz and its relation to structural defects and Ti contents

Abstract The origin of the common blue 450 nm (2.8 eV) cathodoluminescence (CL) emission in natural and synthetic quartz has been investigated using a combination of CL microscopy and spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and trace-element analysis by electron micro-probe analysis as well as inductively coupled plasma-mass spectrometry (ICP-MS). The study shows that the appearance of the ~450 nm emission band can be attributed to two different defects in quartz. First, a transient luminescence can be explained by structural defects in oxygen deficient quartz. The luminescence model implies self-trapped exciton (STE) emission related to oxygen vacancies. This type of CL emission is frequent in high-purity synthetic quartz and natural quartz of hydrothermal origin. Second, in Ti-rich quartz from natural samples (e.g., quartz phenocrysts in rhyolites) and synthetic quartz of Ti-diffusion experiments, an additional 450 nm (2.8 eV) emission was detected, which is stable under the electron beam. The intensity of this ~450 nm emission band correlates with the concentration of trace Ti in quartz, and substitutional Ti4+ at the Si4+ position was proved by EPR spectroscopy. In quartz crystals with elevated Ti concentrations both intrinsic and extrinsic blue CL emissions at ~450 nm can coexist, hindering a thorough characterization and quantification of the CL signal. A reliable distinction of the two different CL emission bands is possible by fitting the peaks of the CL spectra, and the peak width of the 450 nm emission can be used to differentiate the STE from the Ti4+ emission. However, the definitive technique is through the observation of CL peak shape change over time at a point by collecting a time series of CL spectra in conjunction with EPR spectroscopy and trace-element analysis of the Ti concentration.

Thermoluminescence properties and new insights on the UV-vis absorption features of colorless quartz after γ-ray irradiation.

In this paper, we present the results of research on the thermoluminescence (TL) and optical absorption (OA) properties of colorless natural quartz (including natural quartz samples, sodium ion (Na+) rich samples (by diffusion), and alkali metal (M+) ion poor samples (by sweep)). In detail, the relationship between the TL glow peaks and the emission wavelength was determined. The dynamics parameters (E T, s, τ) have been computed for all TL peaks on the glow curve. The recombination mechanism electron-hole with the participation of the region energy has been determined for all electron traps in the temperature range of 50-430 °C through thermally stimulated conductivity measurement (TSC). Nonlinearity and approaching signal saturation are observed at doses above 22 Gy for the electron trap at 110 °C, above 45 Gy for the electron trap at 238 °C, and 80 Gy for the electron traps at 325 °C and 375 °C. The role of irradiation and heat treatment in the formation of absorption centers as well as the relationship of these centers to electronic traps have been also investigated in detail. The role of M+ ions and hydrogen ions (H+) for the absorption bands in the UV-vis region has been discussed. The results of the combination of the TL measurement and monochromatic light absorption according to temperature show that the TL process occurs concurrently with the reduction of the absorbent center produced in the irradiation process.

Study on the visible-light absorption of quartz with different valence states of iron

Synthetic colorless quartz with ion-implanted iron is compared with natural citrine quartz containing iron to study their coloring mechanisms after heating in different atmospheres.

Influence of aluminium doping on high purity quartz glass properties.

High purity natural quartz is used as raw material for the manufacture of quartz glass crucibles for solar-grade silicon ingots production. One key challenge for cost-effective ingot pulling is to maximise the ability of the crucible to withstand the process conditions (i.e., silicon load and temperature about 1500 °C) without deformation. In order to improve this glass property, aluminium was coated into the raw quartz materials. Our results showed that an addition of up to 1000 wt ppm Al substantially reduces deformation of glass and improves viscosity at high temperatures. This is likely due to the reduction of stability of OH groups in the quartz glass as well as a trapping effect of aluminium on oxygen vacancies. This hypothesis is also supported by atomistic models. In the presence of Al, formation energies of silanol groups (Si-O-H) were much higher than without. Furthermore, the presence of Al in the structure significantly reduces mobility of the oxygen vacancies. It was also found that formation of oxygen vacancies hinders cristobalite crystallisation, on the other hand, Al atoms themselves induce local weakening of the Si-O bond which accelerates the kinetics of the reconstructive phase transition from glassy state to crystalline phase. This was also confirmed experimentally in our study.

Mathematical Modeling of Technological Processes of Concreting Monolithic Structures From Fine-Grained Mixtures

Introduction. The introduction of innovative technologies and materials in the construction industry is constrained by a number of reasons associated with insufficient knowledge of technological processes and the increased cost of highly efficient innovative materials. Therefore, studies in the field of monolithic concrete technology, reflecting the features of concreting structures from self-compacting mixtures and aimed at reducing their cost due to the use of construction waste, are relevant. The purpose of this work is experimental and statistical modeling of rheological characteristics of finegrained self-compacting concrete mixtures and physical and mechanical properties of concretes depending on the influence of two recipe factors — consumption of superplastifying additive and particle size distribution of aggregate including construction wastes.Materials and Methods. For the preparation of fine-grained self-compacting concrete mixtures, portlandcement CEM 0 52,5N, natural quartz sand and crushed concrete sand of a mixture of three fractions of 0.63–5.0 mm and a chemical additive - a superplasticizer based on polycarboxylate esters Polyplast PK were used. Process characteristics of fine-grained self-compacting mixtures (workability, viscosity, fluidity) were determined by standard methods. The shear limits of the mixtures were set by means of an instrument comprising a cylinder with a nozzle and a glass base with circumferential marking. Modeling of rheological and physical-mechanical properties of fine-grained self-compacting concretes was carried out using a two-factor simplex-summed plan on a hexagon inscribed in a circle, which is one of the most convenient for solving technological problems of construction materials science.Results. Experimental-statistical models of rheological characteristics of fine-grained self-compacting mixtures and strength properties of concrete were obtained, adequately describing experimental data.Discussion and Conclusion. The use of mathematical planning methods of the experiment made it possible to comprehensively assess the influence of the two most significant recipe factors on the technological processes of concreting monolithic reinforced concrete structures from fine-grained self-compacting mixtures using aggregate from construction waste. It was established that optimal content of grains from crushed concrete in natural sand is 30–35 %, and dosage of superplasticizer Polyplast PK is 1.2–1.25 % of binder weight.