Quartz Research Articles

МЕХАНОАКТИВАЦІЯ ПОРТЛАНДЦЕМЕНТУ ТА ЇЇ ВПЛИВ НА ВЛАСТИВОСТІ БУДІВЕЛЬНИХ КОМПОЗИЦІЙ РІЗНОГО ПРИЗНАЧЕННЯ

The issues considered in the article are related to determining the effect of mechanical activation on the properties of cement-water compositions and building mortars based on them. The activation of cement in combination with the use of ground quartz sand and the superplasticizer Relaxol-Super PC is relevant for this study. The amount of quartz sand was adjusted in the range from 0 to 40% of the cement mass, and the superplasticizer (0,15 – 1,5%) of the binder mass. The use of this technology ensures acceleration of cement hydration processes, maintaining the required level of composition mobility with a lower consumption of mixing water, and intensification of exothermic heating. The presented experimental data made it possible to evaluate the effect of the binder activation period and the superplasticizer consumption on the flow of the aqueous cement-containing composition. It was found that the main contribution to the decrease in the water-solid ratio (provided that equiviscous compositions are obtained) is achieved by activating the cement-containing composition for 180 sec. with the addition of 1,5% superplasticizing additive. The water-solid ratio decreases by more than 50%. A further increase in the amount of plasticizer has low efficiency and has little effect on decreasing the water-solid ratio. Activation in combination with reduced water hardening of the cement-water composition contributes to both an increase in the heating intensity and an increase in its maximum temperature. After activation, the maximum temperature increased by 5-11% compared to the non-activated cement-water composition. The peak of the exothermic reaction for the mechanically activated cement-water composition occurs 3 hours earlier compared to the non-activated mixture. The increase in the strength of the mortar on mechanically activated cement with the addition of a superplasticizing additive reached 71% compared to the control.

SOME SEA GLASS PEBBLES FROM SÃO MIGUEL AZORES, PORTUGAL: PHYSICAL FEATURES, CHEMISTRY AND POTENTIAL RAW MATERIALS

Three Sea Glass pebbles collected on the shoreline of the island of São Miguel Azores, in Portugal, called white, blue and black, were analyzed by mesoscopic means, and by XRD, XRF (handheld), and SEM-EDS. They are rounded, matte, and translucent, with a hardness of around 6 and low density. They are all amorphous to XRD. All three have the same proportion in Si (SiO2) and Al, while they differ in most of the other chemical components. White and blue are sodium-potassium-barium, and black are sodium-calcium. Blue has Co as its pigment, while black has Fe/Mn oxyhydroxides. It is likely that quartz sand, quartz containing Al and Ti, was added at least in part as plant ash (Na, K, Mg, S, Cl). However, Ba may have had calcined barite as its raw material, which appears sporadically in microaggregates. Therefore, the Azores SG could be classified as possible genuine sea glass.

Insights into the synergistic effects between deposited Fe oxides and dissolved organic matter in influencing perfluorooctanoic acid transport in saturated porous media

Perfluorooctanoic acid (PFOA) transport in the subsurface environment is relevant to drinking water safety, while the compounding effects of soil components on PFOA migration are poorly understood. Laboratory miscible-displacement experiments were conducted using saturated sand columns to explore how metal oxide surfaces and dissolved organic matter (DOM) jointly affect PFOA transport in porous media. Retardation factors indicated that Fe oxide coating inhibited PFOA migration due to electrostatic interaction. However, PFOA recovery rates changed insignificantly, decreasing by less than 4 % when the proportion of Fe oxide-coated sand reached 50 %. DOM (1 mg/L humic acid) in the pore water slightly decreased PFOA recovery rates (by about 10 %) in quartz sand, indicating the effect of hydrophobic interaction on PFOA migration. When the PFOA solution containing 1 mg/L humic acid was injected into the column containing Fe oxide-coated sand, PFOA recovery was significantly decreased by nearly 20 %, and the retardation factor was more than doubled. This could be attributed to the stronger hydrophobic effect provided by the higher DOM deposition on the Fe oxide surface. These results, supported by SEM-EDS, zeta potential, and model fitting data, highlight the microscopic mechanisms by which interactions between metal oxides and DOM influence PFOA transport. However, this inhibitory effect disappeared at higher humic acid concentrations (20 mg/L), indicating the risk of PFOA re-migration when the DOM concentration greatly exceeds the adsorption capacity of the media for it. The findings of this work have implications for predicting or controlling the environmental risks of PFOA in soil and groundwater.

A Simplified Calibration Procedure for DEM Simulations of Granular Material Flow

The discrete element method (DEM) has emerged as an essential computational tool in geotechnical engineering for the simulation of granular materials, offering significant advantages over traditional continuum-based methods such as the finite element method (FEM) and the finite difference method (FDM). The DEM’s ability to model particle-level interactions, including contact forces, rotations, and particle breakage, allows for a more precise understanding of granular media behavior under various loading conditions. However, accurate DEM simulations require meticulous calibration of input parameters, such as particle density, stiffness, and friction, to effectively replicate real-world behavior. This study proposes a simplified calibration procedure, intended to be conducted prior to any granular material flow DEM modeling, based on three fundamental physical tests: bulk density, surface friction, and angle of repose. The ability of these tests, conducted on dry quartz sand, to accurately determine DEM micromechanical parameters, was validated through numerical simulation of cylinder tests with varying height-to-radius ratios. The results demonstrated that this calibration approach effectively reduced computational complexity while maintaining high accuracy, with validation errors of 0% to 12%. This research underscores the efficacy of simplified DEM calibration methods in enhancing the predictive reliability of simulations, particularly for sand modeling in geotechnical applications.

Sensor parameters and adsorption behaviour of rhodamine-based polyacrylonitrile (PAN) nanofiber against dichloromethane vapour

This study is focused on the determination of sensor and adsorption parameters ofrhodamine-based polyacrylonitrile (PAN) nanofiber during the dichloromethane vapour exposure due to a very limited investigation of the rhodamine-based PAN nanofiber sensor. Quartz crystal microbalance (QCM) measurement system is employed to monitor the sensor response to dichloromethane vapour. This nanofiber sensor demonstrates a highly sensitive, stable, reproducible response and concentration dependence behaviour. A good stability, with an excellent recovery occurred. Sensor parameters such as the limit of detection (153 ppm), the limit of quantification (465 ppm), the sensitivity (0.0215 Hz/ppm), response (2 s) and recovery (3 s) times are determined using QCM measurement results. Pseudo first-order and Elovich adsorption models have proved that dichloromethane vapours are adsorbed bythis nanofiber sensor andthe amount of vapour adsorption rate is increased when the concentration of dichloromethane vapour increases.Owing to its achieved sensor parameters, high adsorption feature and simple fabrication process with a low cost, this proposed sensing device is expected to be a promising alternative for monitoring dichloromethane vapour sensing application at room temperature.

Viscoelastic Properties of Electrospray‐Deposited Polymer Shells via Quartz Crystal Microbalance With Dissipation (QCM‐D)

AbstractMultilayer polymer films are extensively used in multiphase separation. Electrospray deposition (ESD) is an important technique for fabricating such films with tunable morphology. Viscoelastic properties of polystyrene (PS) nanoshell coatings produced by ESD on gold and spin‐coated PS surfaces are evaluated using Quartz Crystal Microbalance with Dissipation (QCM‐D). The thickness of PS films on gold increases with flow rate from ∼200 nm at 0.5 to ∼400 nm at 1.5 mL h−1, accompanied by an order‐of‐magnitude increase in dissipation due to larger particle sizes from shorter droplet flight times. This effect is absent on spin–coated PS films, suggesting the onset of the self‐limiting effect of charges. Although the shear moduli for ESD films calculated from Voigt models is only 0.08%–0.20% of the bulk PS modulus, the stiffness ratio of spray‐coated PS to a single shell is (5.00–13.3) × 103 m−1, due to shell–shell and shell–substrate interactions. These are novel results related to the interparticle friction obtained using QCM‐D for the first time. This work demonstrates that mechanical properties of particulate viscoelastic films with potential applications in high surface area sensors, such as size‐selective membranes for protein or electrolyte adsorption, can be evalauted by QCM‐D with nanograms of material.

Approaches for predicting the soil-water characteristic curves of compacted quartz sand based on particle packing theory

The soil-water characteristic curve (SWCC) is an important basis for describing hydraulic properties, which is closely related to environmental problems such as the migration of toxic substances from groundwater and soil. The SWCC models vary considerably with respect to the void ratio or bulk density. However, the void ratio and bulk density of the same soil change at different depths or positions within a flat space. Accurate simulation or calculation requires a precise SWCC, but measuring every SWCC under each density or void ratio condition is difficult. In this study, two particle packing models, the Kwan model and the modified linear packing density model (MLPDM), were introduced into the van Genuchten (VG) model to predict the SWCC for soil at the minimum void ratio (the maximum dry density). Then, the prediction method of the SWCCs for the same soil with different densities or void ratios was given. A series of laboratory tests using quartz sand mixtures were conducted to verify the accuracy of two extended models (the K-VG model and the M-VG model). For the K-VG model, the average RMSE was 0.020. For the M-VG model, the average RMSE was 0.017. In general, the SWCCs predicted by the two extended models were consistent with the measured values.

Material Design and Performance Study of a Porous Sound-Absorbing Sound Barrier

A new type of porous sound-absorbing sound barrier was developed with quartz sand and self-developed polysiloxane resin. The forming process of the material was studied. The test specimens of the porous sound-absorbing sound barrier were prepared with different mesh numbers of quartz sand and different proportions of resin, and the void properties, compressive strength, durability, and acoustic performance were investigated. Based on the mix design results, it is suggested that 20-mesh quartz sand and a 10:1 mass ratio of quartz sand are used to prepare the porous sound-absorbing sound barrier. The durability study showed that the porous sound-absorbing sound-barrier material had good salt and alkali resistance, poor acid resistance, good water stability, and freeze–thaw stability. The laboratory acoustic test and practical engineering application results showed that the porous sound-absorbing sound barrier had excellent acoustic performance and good noise-reduction effects.

Research of heat conductivity of quartz material

In the article the results of a study of heat conductivity and thermal resistance of quartz-containing materials were presented. The object of the study was a quartz mineral from the Aktas deposit, located in the Ulytau district of the Karaganda region. The initial size was a piece of quartz mineral measuring 5–10 mm, which was disassembled mechanically. To prepare the samples under study, quartz powder 0.2 mm thick, crushed by the electric pulse method, was used. Electropulse technology is one of the methods based on the influence of Yutkin, accompanied by the formation of a specially formed high-voltage pulsed electrical discharge inside a volume of liquid. The pulse discharge frequency of the electrohydropulse installation for grinding the mineral to the required fraction was f = 3 Hz, the pulse capacitor capacitance C = 0.4 μF, the pulse discharge voltage U = 18–37 kV. The samples under study were made in the following dimensions: width 100 mm, length 100 mm, height 25 mm. To evaluate the thermophysical properties of manufactured samples in a stationary mode, the ITP-МG4 “100” installation was used, which determines the heat conductivity and thermal resistance of materials for thermal insulation of industrial equipment and pipelines in accordance with GOST 7076, based on the thermoelectric method, and GOST 30256, based on the thermal probe method. As a result of the study, a graph of the temperature dependence of heat conductivity and thermal resistance of quartz-containing materials was obtained. Based on the results obtained, it was established that the thermophysical parameters of the sample containing quartz are lower compared to the sample consisting of cement.

AN ANALYSIS ON THE USE OF MODIFIED EXPANDED PERLITE AND PUMICE IN INORGANIC BONDED FIBROUS COMPOSITE BOARDS

It is often stated that there is an energy efficiency difference between optimum energy use and actual energy use in the world. In the construction industry, various building materials are produced and used to optimize energy efficiency in buildings. Among these building materials, inorganic bonded fibrous composite boards, whose energy efficiency criteria have begun to be improved, are widely used both in Türkiye and in the world. This article presents an experimental analysis of the utilization of modified expanded perlite and pumice as key constituents in the development of inorganic bonded fibrous composite boards. The study investigates the influence of these modified porous materials on the physical, mechanical, and thermal properties of the composite boards. For this purpose; composite mortars were produced using micronized quartz sand, a hybrid fiber consisting of cellulose and glass fiber, modified expanded perlite (MEP) with stearic acid (1, 2, 3, 4, 5, 6, 7, 8, 9 wt.%) and modified pumice (MPU) with stearic acid (1, 2, 3, 4, 5, 6, 7, 8, 9 wt.%). In order to make a comparison, a control mortar that did not contain modified expanded perlite and modified pumice was produced. Through a series of experiments, it is concluded that the density values of all other mixture designs with MEP and MPU aggregate additives under equivalent conditions are lower than the control sample. The water absorption values of the samples always remained below the control sample, and with the increase in the MPU ratio and decrease in the MEP ratio, the water absorption values of the samples also decreased. The average modulus of rupture (MOR) value of control sample in the analysis made after 14 days of curing under ambient conditions is 3.73 MPa. The highest MOR value of the test samples is 3.51 MPa, which is the mixture using the highest MPU. The thermal conductivity value of the control mixture is 0.352 W/mK. The thermal conductivity value of test mixtures with MEP and MPU aggregates varies between 0.175 W/mK and 0.287 W/mK.

Progress of joint process research on purification of high purity quartz sand

High-purity quartz sand is an important raw material for semiconductors, photovoltaics, aerospace and other cutting-edge fields, high-quality natural crystals can no longer meet the urgent demand for high-purity quartz in the domestic market, and it is imperative to accelerate the realisation of high-quality quartz purification technology from non-quality mineral sources. This paper summarises the joint process flow in the unused scenario, and outlines the main methods for the purification of quartz sand in China at present, including pretreatment, ultrasound-assisted leaching, chlorination roasting, etc., from the point of view of the joint process, and puts forward the problems that exist in these methods, so as to provide certain references for the research on the purification process of high-purity quartz sand in China.

Quantification of scalings in dynamic environments using a combination of Quartz Crystal Microbalance and Raman Microscopy

Quantification of scalings in dynamic environments using a combination of Quartz Crystal Microbalance and Raman Microscopy

Effect of loading rate on local deformation of rock-like models with locked segment

To investigate the influence of loading rate on the local deformation and failure characteristics of rock-like models with a locked segment, this study fabricated them using quartz sand and barite powder as aggregates, and gypsum as cementing material. Uniaxial compression tests, combined with strain cube monitoring and the digital image correlation technique, were employed to analyze the mechanical properties, internal and external deformation characteristics, crack propagation, and failure modes at different loading rates. The results showed that as the loading rate increased, the strength of these models initially increased significantly and then slightly decreased, primarily due to the complex interaction between the longitudinal and transverse deformations of the models and the stress concentration intensity at the crack tips. The fluctuation in the principal strain axis's deflection angle revealed the complex process of stress wave propagation and particle adjustment within the models, with more pronounced fluctuations observed at higher loading rates. The stress intensity factors, KIand KII, at the crack tips first increased and then decreased with increasing loading rate, with KI consistently higher than KII. The strain concentration phenomenon in the rock-like models occurred earlier with increasing loading rates, and the corresponding crack closure stress exhibited a decreasing trend. Higher loading rates caused earlier crack initiation and faster propagation. As the loading rate increased, the crack paths shortened, and both damage density and severity increased significantly, indicating brittle failure. This study provides important experimental evidence and theoretical support for understanding the effects of loading rate in rock mass engineering.

Experimental study on the influence of particle morphology on compression characteristics of coral sand in South China Sea

Particle morphology is an important physical parameter that influences the engineering properties of coral sand, especially its compressibility. According to the quantitative analysis of particle morphology via the dynamic image analysis technology, a series of one-dimensional compression tests on coral sand and quartz sand with different particle morphology and densities were performed to reveal the effect of particle morphology on the compressibility of coral sand. The results demonstrated that the morphology of particles can be quantified using the shape-angularity group indicator (SAGI), whereas the SAGI of coral sand was greater than that of quartz sand. Coral sand exhibited a yield stress ranging from 1 to 2.5 MPa, and compressive deformations in both coral sand and quartz sand were dominated by irreversible plastic deformation. As the SAGI and densification increased, the number of particle coordination increased while the contact stress between grains decreased, which caused the yield stress of coral sand specimens to increase as well as the compression index and particle crushing rate to decrease. The SAGI of quartz sand particles remained relatively unchanged while that of coral sand particles gradually decreased after crushing, i.e., the coral sand particles developed a more regular shape after crushing.

The effect of manganese and carbon on the mechanical properties of the welded layer of the bucket teeth of the Hadfield steel excavator

The paper investigates the effect of the surfacing composition’s chemical structure (the manganese and carbon concentrations’ ratio) on the mechanical properties of the surfacing layer on Hadfield steel for increasing the durability of the products made from it, namely the excavator bucket’s teeth. Two criteria, namely the impact toughness and wear resistance of the coating, were chosen as optimization parameters. The assessment of the impact strength of the deposited coating was carried out on the Sharpie samples on the pendulum copra, and the wear test was carried out according to the Brinly-Haworth scheme in the conditions of samples’ abrasion with quartz sand. Wear resistance of Hadfield steel, containing 1.1% C and 13% Mn, was taken as a unit of wear resistance in these experiments. To determine the optimal coating modes, the active experiment with the application of mathematical planning methods was conducted. The obtained response surfaces and graphs of equal output lines make it possible to establish the level of studied factors’ influence on the optimization parameter. In order to analyze the influence of given factors on the optimization criteria, scatter plots with histograms were constructed, which make it possible to determine the rational values ​​of the selected optimization criteria graphically - impact toughness and wear resistance of the coating

X-ray imaging crystal spectrometer (XICS) diagnostic on the HL-3 tokamak

The construction of an X-ray imaging crystal spectrometer (XICS) diagnostic system on the HL-3 tokamak plays a crucial role in measuring core plasma parameter profiles, including ion temperature, electron temperature, rotational velocity, and impurity radiation profiles. This diagnostic system has been specifically designed to provide detailed and accurate data essential for understanding the behavior and characteristics of tokamak plasma. The resonance spectral line (w line of Ar XVII at 3.9494 Å) and its satellites of helium-like argon ions were chosen on the basis of the HL-3 parameter range. A spherically bent quartz crystal (1012) with a lattice constant of 2d = 4.562 Å, a curvature radius of Rc = 3.0 m, and a size of 10 cm (high) × 5 cm (wide) was mounted on an adjustable displacement platform in the XICS system. The position was adjusted in three dimensions (vertical, inclined, rotation) to effectively record the spectra of the helium-like argon ions. The XICS has a tangential angle of 49° for the toroidal direction in the magnetic axis. This layout accounts for 65.6 % of the toroidal rotation velocity component. The XICS system was set at an 11° poloidal angle in the mid-plane to cover a plasma range of 10 cm above to 50 cm below the mid-plane, which corresponds to the q = 1 surface of the HL-3 plasma (elongation κ > 1.8). This XICS layout produced a spectrum with poloidal and toroidal rotational contributions, requiring decoupling through data processing. In general, because the contribution of the poloidal rotation velocity is much smaller than that of the toroidal rotation velocity, it can be ignored. The XICS system offers a spatial resolution of ∼1.5 cm and a temporal resolution of 5–10 ms on the basis of a high-performance PILATUS3 × 900 K detector. The spectral resolution is λ/Δλ∼4×104, which satisfies the experimental measurement requirements. Preliminary results of ion and electron temperature profiles were obtained for the HL-3 tokamak.

Characteristics and Mechanism of Hematite Dissolution and Release on Arsenic Migration in Heterogeneous Materials

The migration of arsenic in groundwater is influenced by the heterogeneity of the medium, and the presence of iron minerals adds complexity and uncertainty to this effect. In this study, a stratified heterogeneous sand column with an embedded hematite lens at the coarse-to-medium sand interface was designed. We introduced an arsenic-laden solution and controlled groundwater flow to investigate the spatiotemporal characteristics of arsenic migration and the impact of hematite dissolution. The results showed that the medium structure significantly influenced the arsenic migration and distribution within the lens-containing sand column. The clay layers directed the lateral migration of arsenic, and the arsenic concentrations in deeper layers were up to seven times greater than those on the surface. The extraction experiments of solid-phase arsenic revealed that the main adsorption modes on quartz sand surfaces were the specific adsorption (F2) and adsorption on weakly crystalline iron–aluminum oxides (F3), correlating to the specific and colloidal adsorption modes, respectively. Monitoring the total iron ions (Fe(aq)) revealed rapid increases within the first 14 days, reaching a maximum on day 15, and then gradually declining; these results indicate that hematite did not continuously dissolve. This study can aid in the prevention and control of arsenic contamination in groundwater.

Effect of particle size, water saturation, inorganic salt and methane on the phase equilibrium of CO2 hydrates in sediments

Understanding the thermal stability of gas hydrate in complex marine geological environment is of importance to hydrate-based carbon sequestration. In this work, the factors affecting the equilibrium of CO2 hydrate in ocean sediments, including quartz sands, inorganic salts and gas impurities were quantitatively measured in a temperature range from 273 to 283 K and a phase equilibrium model of hydrate was established. To reveal the distribution in pore structure, the micro-morphologies of hydrate-bearing sediments were measured by cryo-SEM. Results showed that reduction of initial water saturation, addition of NaCl and CH4 were found to have inhibitory effect on CO2 hydrate equilibrium. Initial water saturation reduced the equilibrium temperature by the capillary pressure, but only 0.3–0.7 K temperature depression was observed as the water saturation reduced to 5 %. About 5.7 K in the average temperature depression was found by the addition of 10 wt% NaCl and 24 mol% CH4. NaCl and CH4 influenced the hydrate equilibrium by changing the water activity and chemical potential of hydrate water lattice. SEM images showed that the hydrate formed in pores of quartz sand had porous surface and coated the sand particles like a layer of cells which are 5–20 μm in diameter, suggesting the hydrate layer exists between the liquid and gas phase. Based on the van der Waals-Platteeuw model, a hydrate equilibrium model was developed. The model provided a good prediction of the hydrate equilibrium in the presence of quartz sand, NaCl and CH4 with an averaged deviation of ±4.2 %, which had the potential to be applicated in more complexed ocean sedimentary environment.

Dual approach in textile wastewater treatment: optimisation and comparison of fluidised-bed and conventional Fenton processes

ABSTRACT This study optimises secondary textile dyeing wastewater removal using fluidised-bed Fenton (FBR-Fenton) and standard Fenton processes for chemical oxygen demand (COD) and colour removal efficiency. The Box–Behnken response surface approach optimised pH, iron ion concentration, and hydrogen peroxide concentration. At pH 3.3, [Fe2+] = 2.6 mm, [H2O2] = 6.4 mm in the fluidised bed reactor with 67 g/L quartz sand, with a 50% bed expansion after 40 min, the FBR-Fenton process removed 75.8% COD and 98.0% colour. The standard Fenton method was tuned to pH 3.2, [Fe2+] = 3.1 mm, [H2O2] = 6.6 mm, and COD and colour removal effectiveness of 69.7% and 97.5%, respectively. FBR-Fenton enhanced COD and total iron removal efficiency, reduced chemicals, and reduced sludge by 28.0% compared to conventional Fenton. This study also showed quartz sand reusability in FBR-Fenton treatment cycles. Experimental results matched response surface model predictions, proving regression equation correctness.

Characterization and application of fine aggregate from Rio Branco do Sul – PR with quartz filler additions: innovations in concrete performance

Understanding the properties of a material is essential to ensure its efficient application and achieve good results. This study addresses the characterization and applicability of quartz sand from the Rio Branco do Sul region, Paraná (PR), Brazil, in civil construction, focusing on procedures such as ceramic block laying, plastering, and rendering. Additionally, quartz filler (quartz powder) was added as a pozzolanic additive in fractions of 10% and 20% relative to the weight of the cement, along with samples without additives, to compare the results. To evaluate performance, the test specimens were subjected to two curing processes: thermal curing, aimed at activating pozzolanic reactions between the quartz powder and the chemical components of the concrete; and wet curing, which, although it does not stimulate chemical reactions, preserves the physical effects of the addition, such as reducing the concrete’s porosity and increasing its compressive strength. The specimens were analyzed at 7, 14, 21, and 28 days of age.