Silica Sand Research Articles

Adsorption of Fluoride from Water Using Aluminum-Coated Silica Adsorbents: Comparison of Silica Sand and Microcrystalline Silica

Two aluminum-coated silica adsorbents were evaluated using silica sand and microcrystalline silica as aluminum-oxide-based adsorbents with different crystalline silica base materials. The aluminum coating contained mainly amorphous aluminum oxides for both aluminum-coated silica adsorbents. The adsorption of fluoride onto both adsorbents was favorable according to the Langmuir and Freundlich adsorption equations, while the physical adsorption of fluoride occurred for both adsorbents according to the Dubinin–Raduskevish (D-R) equation. The adsorption of fluoride was stronger for aluminum-coated silica sand based on adsorption parameters from the Langmuir, Freundlich, and D-R adsorption equations, with the stronger binding of fluoride likely due to the observed greater specific adsorption. The adsorption capacity determined using the Langmuir equation was about 7 times greater for aluminum-coated microcrystalline silica primarily due to the 1.22-orders-of-magnitude-larger surface area of aluminum-coated microcrystalline silica, whereas the surface-normalized adsorption capacity was 2.4 times greater for aluminum-coated silica sand, possibly due to more aluminum being present on the surface of silica sand. Fluoride adsorption occurred over a broad pH range from 3 to 10 for both adsorbents, with nearly the same pHPZC of 9.6, while aluminum-coated microcrystalline silica displayed a higher selectivity for fluoride adsorption from different natural water sources.

Investigation on mechanical behavior of engineered cementitious composites incorporating alkali‐resistant glass fiber and quarry dust

AbstractAt present, engineered cementitious composites (ECC) are rapidly replacing ordinary concrete in the building production due to its superior durability and mechanical qualities. Enormous researches have been done on ECC incorporating various fibers, industrial wastes, supplementary cementitious materials and super plasticizers. As far as fiber is concerned, poly vinyl alcohol fiber was widely explored. In this study, attempt has been made to involve alkali resistant glass fiber as a replacement for poly vinyl alcohol fiber. In addition, the high rate related with ECC as a result of the utilization of micro‐sized silica sand has restricted its extensive pertinences. Thus, this study recommends utilization of quarry dust to replace fine silica sand in the ECC at amounts ranging from 0% to 100% in order to establish a green, sustainable and cost‐effective ECC. The flowability and mechanical demeanor of the ECC mixtures in terms of the tensile, compressive and flexural properties were evaluated. It is arrived that 2% of volume fraction would be the optimum dosage by which better mechanical properties can be achieved. As a result of the present research findings, it is found that the quarry dust could be a better substitute for silica sand up to 75% without any compromise in compressive and flexural strengths. To attain higher tensile qualities, however, it might not be appropriate to replace more than 50% of the silica sand with quarry dust. Cost analysis of the ECC mixtures show that using quarry dust as aggregate is both cost‐effective and sustainable.

Expression of Concern: Synergy of silica sand and waste plastics as thermoplastic composites on abrasive wear characteristics under conditions of different loads and sliding speeds

Expression of Concern: Synergy of silica sand and waste plastics as thermoplastic composites on abrasive wear characteristics under conditions of different loads and sliding speeds

Changes of Temperature and Moisture Distribution over Time by Thermo-Hydro-Chemical (T-H-C)-Coupled Analysis in Buffer Material Focusing on Montmorillonite Content

Bentonite is used as a buffer material in engineered barriers for the geological disposal of high-level radioactive waste. The buffer material will be made of bentonite, a natural clay, mixed with silica sand. The buffer material is affected by decay heat from high-level radioactive waste, infiltration of groundwater, and swelling of the buffer material. The analysis of these factors requires coupled analysis of heat transfer, moisture transfer, and groundwater chemistry. The purpose of this study is to develop a model to evaluate bentonite types and silica sand content in a unified manner for thermo-hydro-chemical (T-H-C)-coupled analysis in buffer materials. We focused on the content of the clay mineral montmorillonite, which is the main component of bentonite, and developed a model to derive the moisture diffusion coefficient of liquid water and water vapor based on Philip and de Vries, and Kozeny–Carman. The evolutions of the temperature and moisture distribution in the buffer material were analyzed, and the validity of each distribution was confirmed by comparison with the measured data obtained from an in situ experiment at 350 m in depth at the Horonobe Underground Research Center, Hokkaido, Japan.

Co-Gasification of Polyethylene and Biomass in Catalytic Bed Material

In this work, a simplified comprehensive three-dimensional numerical model is developed to study the effect of hydrogen production on co-gasification of biomass and low-density polyethylene (LDPE). CFD software AVL Fire 2020 inbuilt algorithms were employed to develop the gas phase while the solid phase was developed by user-defined FORTRAN subroutines. Solid hydrodynamics, fuel conversion, homogenous and non-homogenous chemical reactions, and heat transfer, including radiation, subroutines were defined and incorporated into AVL FIRE explicitly. Species concentrations of the syngas were analyzed for co-gasification of Beechwood and LDPE for three distinct types of bed materials (silica sand, Na-Y zeolite, and ZSM-5 zeolite). Then, the model is validated with experiment results available in the literature for a lab-scale fluidized bed reactor. The highest hydrogen production was observed in Na-Y zeolite followed by ZSM-5 zeolite and silica in both numerical and experimental analysis for the co-gasification of Beechwood and LDPE, providing a reasonable agreement between the numerical and the experimental results. Therefore, the current model predicts the enhancement of the quality of hydrogen-rich syngas through the application of co-pyrolysis within a fluidized bed reactor, incorporating a catalytic bed material.

Physically simulating the dispersion of chopped carbon fibres in mortar

Carbon fibre dispersion exerts a critical influence on the characteristics of carbon fibre-reinforced cement mortars (CFRCMs). This study accordingly investigated the dispersion of chopped carbon fibres (CCFs) in mortar using physical experiments with a transparent simulated mortar system comprising colloidal silica and silica sand as replacements for cement and aggregate, respectively, and evaluated the microstructures and conductive performances of corresponding CFRCM specimens. In the simulated solutions, bundled CCFs in order were more prone to disperse into single fibres than clustered ones in disorder due to no physical fixation, colloidal silica prevented the formation of CCF clusters during stirring, and the shear force of moving sand dispersed but also broke CCFs. In the CFRCMs, sand aggregates reaggregated dispersed CCFs while larger sand particles increased CCF dispersion and improved specimen conductivity. Thus, decreasing the amount of CCFs clusters before dispersion, and a short stirring time in a single direction should be provided to prepare CFRCMs with well-dispersed CCFs. Meanwhile, a more dispersible aggregate and less formation of void should be also essential.

Rapid, graded sand preparation method using grain size distribution results for cement mortar testing

Adhering to ASTM C109/C109M-20 standards ensures quality in cement mortar specimens. However, achieving the required sand gradation per ASTM C778-21 can be challenging. This paper presents a faster method for adjusting sand gradation without compromising ASTM quality standards. The proposed method involves analyzing six silica sand samples of different gradations, pre-screening sands, using Excel Solver for optimal mixture ratios, making automated gradation tweaks with precise calculations, and validating the gradation to ensure ASTM compliance. After making the adjustments, compressive strength tests were conducted on mortars with the modified sands, and the results were compared with those of standard-graded sand. Based on statistical analysis, the new method yielded reliable outcomes with compressive strengths similar to standard sands. This innovation offers a more efficient alternative, paving the way for streamlined practices in civil engineering.

Waste silica sand as a possible pozzolanic filler to produce cement mortars: experimental investigation

The present paper discusses experimental results obtained on several mortars prepared using a commercial type1 OPC cement, a commercial limestone aggregate with maximum particles dimension below 5 mm, superplasticizer and water. Different amounts of a waste silica sand, in form of loose powder, derived from the industrial production of refractory blocks, were added to the above basic components. Several additional samples were also prepared using same basic commercial components added by different amounts of a fine limestone filler. This latter set of compositions was used to prepare samples to be used as reference materials. Waste silica sand and fine limestone filler were used as received from their producer. During preparation, pastes containing silica sand showed better workability compared to all the other blended components. All hydrated materials displayed fair compressive strength and low water absorption after curing, but those containing silica sand showed the best mechanical performances due to their low residual porosity and to the pozzolanic reaction which could enable application for the production of structures in direct contact with water or aggressive environments such as sewers or tanks suitable for the containment of organic substances.

Installation of open-ended piles: A numerical investigation into the effects on the state of silica sand

Up to this day, there are great uncertainties in the design procedures of monopiles, especially concerning the soil state condition and penetration response during their installation. A numerical model, based on the Coupled Eulerian method and using the hypoplastic law with intergranular strain, is proposed and validated in this paper, after which a series of open-ended pile installation tests have been carried out numerically, to investigate the influence of the jacked installation on the initial conditions for three types of silica sand. A range of soil densities and pile diameters is considered in this analysis. A full investigation of the installation forces, stress level, changes in volume-stress level and voids ratio is conducted. The numerical solution provided a correlation between the penetration resistance and the granulometric properties of the studied sands. Subsequently, the radial stresses in the surrounding soil mass are correlated with the type of sand and its relative density. The stress-volume state of a set of points in the soil domain during installation is presented and discussed from the critical state framework, revealing the contribution of the in-situ state in the pile installation. Finally, the lateral earth pressure resulting after installation is presented.

Utilization of Bengkalis Beach Sand Silica as Raw Material in the Synthesis of Zeolite 4A

Zeolite 4A is a porous material that is widely used as an adsorbent, catalyst, membrane, ion exchanger, molecular sieve, etc. As a source of silica in the synthesis of zeolite 4A, silica from natural materials, biomass waste or chemicals has been used. In this research, silica extracted from Bengkalis beach sand (BBS) was used as raw material. The silica content in its oxide form, silicon oxide (SiO2) in BBS reaches 90%. The synthesis of zeolite 4A was carried out using a hydrothermal process, by varying the mole ratio of Si/Al from the reactant sodium silicate to sodium aluminate, namely 1.2:1; 1.4:1; 1.6:1 at reaction temperatures of 100, 110 and 120°C. Based on characterization using X-ray diffraction and an infrared spectrometer, the best conditions were obtained at a mole ratio reactant of 1.6, a reaction temperature of 100°C with a crystallinity percentage reaching 80.97%. Based on SEM-EDX analysis, the zeolite has an agglomerated morphology with a Si/Al ratio of around 1.09. The surface area, pore volume, and pore diameter of the synthesized zeolite were analyzed using a Brunauer-Emmet-Teller (BET) technique, respectively 81.844 m2/g, 0.039 cm3/g, and 3.07 nm.

Synergistic effects of cold rolling and age hardening on the hardness and tensile characteristics of AA6061 hybrid composites

The present study involves the fabrication of aluminium alloy 6061 matrix hybrid composites with varying weight fractions of silica sand and copper particles by employing the conventional stir casting method. The combined influence of age hardening (AH) and low temperature thermomechanical treatment (LTMT) on the hardness and tensile properties of AA6061 hybrid composites was investigated. The uniform dispersion of the particles in the matrix was confirmed by microstructure analysis and the improvement of Brinell hardness values. The composites exhibited higher tensile strength and hardness than the base alloy. Both AH and LTMT enhanced the properties of the hybrid composites and a comparison between them revealed the best results for LTMT hybrid composites. The LTMT hybrid composite with 3 wt% silica sand and 3 wt% copper (3S3C) subjected to 12% rolling deformation and aged at 100 °C had the highest hardness and tensile strength of 144.26 HV and 290 MPa respectively. The hardness and tensile strength of AA6061-3S3C hybrid composite subjected to LTMT in peak aged condition showed an improvement of 125 and 97% respectively when compared with those of AA6061 alloy. Fracture surface analysis of the thermomechanical treated composites in peak aged condition showed a mixed mode of failure dominant with the ductile fracture.

Analisis Pembuatan Paving Block Menggunakan Campuran Limbah Pecahan Keramik & Pasir Silika sebagai Pengganti Sebagian Pasir terhadap Kuat Tekan (Literature Review)

This literature article details the results of a review of the latest literature which focuses on the use of ceramic shard waste and silica sand as additional materials in making paving blocks. In the context of sustainable development, this literature highlights the positive potential of utilizing ceramic waste as a contribution to waste reduction and resource efficiency. The addition of silica sand, as an additional material, apparently has a significant effect on increasing the strength and durability of paving blocks. Through a synthesis of information from various studies, this article also highlights the need for further research to optimize ingredient composition and evaluate the overall impact, both in terms of sustainability and product quality. By summarizing key findings, this article provides a holistic view of the use of ceramic shard waste and silica sand in the context of paving block manufacturing, supporting sustainable technological development in the construction sector.

Dug Well Water Quality to Reduce Pollution Parameters Kapasa Village, Biringkanaya District, South Sulawesi

The quality of dug well water should comply with established regulations. The pollution caused by bacteria to water in the ground widens to ± 2 meters at a distance of 5 meters from the source of pollution 3 and narrows to a distance of 11 meters in the direction of the ground flow. This type of research is descriptive research, namely to determine the use of silica sand filter media, activated carbon in filter reactors on reducing TDS, Nitrite (NO2), Dissolved Manganese and MPN Coliform by comparing the composition of the filter media with reference to clean water quality standards Permenkes No. 2 In 2023, the samples in this research were dug wells located in Kapasa Village, Biringkanaya District, Makaasar City. The results of this research after the filtration intervention of manganese media, activated charcoal and silica sand, found that TDS, color, Manganese Nitrite (NO3) had decreased levels of environmental pollution, this is in accordance with the Regulation of the Minister of Health of the Republic of Indonesia Number 2 of 2023. Conclusions from the results research shows that silica sand, manganese and activated charcoal filtration media, TDS, manganese nitrate (NO2) and MPN Coliform can effectively reduce water pollution levels in dug wells in accordance with the Minister of Health Regulation. So the risk of infectious and non-communicable diseases can be overcome with the intervention of silica sand, manganese and activated charcoal filtration media.

Sand Improvement by Surface Percolation Method Using Urease-Containing Substance Extracted from Soybean Seed

Background. In recent decades, the microbial and plant-derived urease have been used for sand stabilization by the calcium carbonate precipitation method, especially with Sporosarcina pasteurii. However, calcium carbonate precipitation using plant-derived urease has received less attention. Purchasing the extracted and purified commercially available plant-derived urease for the sand improvement is costly. The plant-derived urease-containing crude extract (enzyme substance) is cheaper than purified (commercial) urease. In the present study, the feasibility of sand improvement by enzyme-induced calcium carbonate precipitation method was investigated with urease-containing crude extract (extracted from soybean). Methods. The distilled water, instead of phosphate buffer, was used to provide the main enzyme extraction medium. Also, the effects of temperature, time, and dilution on the activity of the urease-containing crude extract by the electrical conductivity meter were investigated. Results. The results showed that the extraction temperature had a significant effect on the behavior of the enzymes, and according to the results, the temperature range between 19 and 25°C is suitable for the enzyme extraction. The four-layer surface percolation method was used to improve the sand, and 0.75 equimolar (eqM) concentration of urea-CaCl2 cementation solution is suitable for sand improvement using the UCE extracted from soybean seed. Conclusion. Silica sand was successfully improved by the EICP method using the four-layer surface percolation method, and significant unconfined compressive strength and elasticity modulus were obtained. XRD and XRF analysis also confirmed the successful precipitation of calcium carbonate between the sand particles.

The Mechanical and Self-Sensing Properties of Carbon Fiber- and Polypropylene Fiber-Reinforced Engineered Cementitious Composites Utilizing Environmentally Friendly Glass Aggregate

In order to facilitate waste glass recycling and enable the monitoring of concrete structures, this study prepares a new type of self-sensing engineered cementitious composite (ECC) via the use of glass sand instead of silica sand. The health monitoring of a concrete structure is achieved through the addition of polypropylene (PP) fibers to enhance the flexural toughness of concrete, and adding carbon fibers (CFs) to make the concrete self aware, enabling it to sense the load changes and structural damage. The fiber dosage of ECC is optimized to analyze the effects of different fiber types and dosages on the mechanical and self-sensing properties of concrete. The results show that the hybrid fibers produce a good synergistic effect on mechanical properties, and the presence of excess fibers causes the mechanical properties of concrete to deteriorate. The critical fiber volume fraction required for the strain hardening of PP ranges from 0.75% vol to 1% vol. At different PP dosages, the CF dosage shows a positive correlation with the initial crack strength. By analyzing the effect of varied curing times and CF doping on the initial resistivity, it is found that the threshold value of CF conductivity is 0.7% vol. The role of CFs in the flexural sensitivity and pressure sensitivity tests is explained from the perspective of fiber distribution, and the fiber distribution theory is verified with scanning electron microscopy (SEM). The optimal level of CF doping for flexural sensitivity and pressure sensitivity is determined to be 1.1% vol and 0.7% vol via the use of self-sensing performance tests, respectively. An increase in PP fiber doping leads to a decrease in the initial resistivity and self-sensing properties of the material. The results of this research provide guidance regarding how to determine the optimal fiber dosage flexibly for different engineering works.

Mechanical performance of low-carbon ultra-high performance engineered cementitious composites (UHP-ECC) with high-volume recycled concrete powder

Reusing recycled concrete powder (RCP) from construction waste for ultra-high performance engineered cementitious composites (UHP-ECC) markedly enhances its sustainability. This paper explores the mechanical properties and environmental benefit of low-carbon UHP-ECC containing high-volume RCP as the replacement of cement, ground granulated blast furnace slag (GGBS) and silica sand. The results indicate that UHP-ECC has a loose microstructure when a high percentage of cement is replaced with RCP, while replacing silica sand with RCP results in a denser microstructure. Substituting 75% of cement with RCP reduces the compressive strength and flexural strength of UHP-ECC by 24% and 17.6%, respectively. Substituting RCP for silica sand and GGBS does not significantly affect the compressive strength of UHP-ECC, albeit slightly reducing its flexural strength. Under the application of uniaxial tensile loading, the introduction of RCP improves the ductility of UHP-ECC at a 25% substitution rate, whether replacing silica sand or binder materials. However, as the substitution rate increases, replacing cement and silica sand with RCP decreases the ductility of UHP-ECC. Specifically, reductions of 10% and 7.6% in ultimate tensile strain are discerned when substituting 75% of cement and 100% of silica sand with RCP in UHP-ECC, respectively. Conversely, substituting a large volume of GGBS with RCP can further enhances the ductility of UHP-ECC, with an 15.5% increase in ultimate tensile strain when replacing all GGBS with RCP. By adjusting the RCP content to serve as an alternative to traditional binders and sand, it is possible to achieve a more sustainable UHP-ECC characterized by ideal mechanical strength and ductility, and RCP-blended UHP-ECC demonstrates favorable environmental and economic benefits.

Binder Jetting 3D Printing of Binary Cement-Siliceous Sand Mixture.

Three-dimensional printing allows accurate geometries to be obtained across a wide range of applications and it is now also moving into the architecture and construction industry. In the present work, a unique binary mix composed of ordinary Portland cement (OPC) and quick-setting cement (QSC) was combined with silica sand aggregate in different proportions for a customized binder jetting 3D printing (BJ3DP) process. Specimens were printed using the blended dry powders and deionized water to determine the impact of the processing variables on the properties of the realized specimens. The results show that the properties are influenced by the binary mix proportions and the layer thickness. The investigation found significant improvement in mechanical performance on increasing the proportion of OPC and optimal conditions were identified with proportions of 35 wt% OPC and 5 wt% QSC. Notable enhancements were also observed as the layer thickness was reduced.

The Effect of Operating Variables on the Performance of Column Flotation of Silica Sand

This paper presents the results of a study performed on silica sand samples to determine the effect of operating parameters (collector type and dosage, solids content in the pulp, pulp pH and air flow rate) on the concentrate grade and mass recovery in laboratory-scale column flotation. Through the analysis of variance (ANOVA), it was determined that the pulp pH had a significant impact on all four of the observed grade parameters (mass contents of SiO2, Al2O3, Fe2O3 and TiO2 in the concentrate). Air flow rate had a significant impact on the mass contents of SiO2 and Al2O3. The solids content in the pulp only significantly affected the mass content of Fe2O3. The mass recovery was significantly influenced by the pulp pH, with a high level of significance (p-value (p) = 0.002917), as well as by the air flow rate (p = 0.010285). On the basis of a model of the relationship between the respective grade parameters and tested operating variables, it was determined that with the use of the Aeromine 3030C collector (at a dosage of 500 g/t) the highest-grade concentrate regarding the mass contents of SiO2, Al2O3 and TiO2 was achieved with a pulp pH within a range from 2.4 to 3 and an air flow rate above 26 L/h. The lowest mass content of Fe2O3 in the concentrate was achieved at a pulp pH in a range from 2.2 to 2.8 and a solids content in the pulp between 2.0% and 3.5%.

Experimental investigation of thawing behavior of saline soils using resistivity method

Abstract Electrical resistivity method has been widely used to study permafrost and to monitor the process of freezing-thawing. However, a thorough understanding of the mechanism of electrical response during thawing is missing. In this study, we investigated the thawing behavior of saline soils in the temperature range from roughly −10 to 15°C considering the effects of soil type and salinity. A total of nine experiments were performed with three soil types (silica sand, sandy soil, and silt) and three salinities (0.01, 0.1, and 1 S m−1). The results show that resistivity variations with temperature can be divided into three stages. In Stage I, tortuosity and unfrozen water content play major roles in the decrease of resistivity. In Stage Ⅱ, which is an isothermal or near isothermal process, resistivity still decreases slightly due to the thawing of residual ice and pore water movement. In Stage III, ionic mobility plays an important impact on decreasing resistivity. In addition, the isothermal process is found to only occur in silica sand that can be explained by latent heat effect. Exponential and linear models linking temperature with resistivity are used to fit the experimental data in Stages I and III. The fitting parameter in different models shows great correlation with soil type and salinity. Furthermore, unfrozen water content below 0°C is also estimated and uncertainty of estimation is analyzed.

Toxicological Evaluation toward Refined Montmorillonite with Human Colon Associated Cells and Human Skin Associated Cells.

Montmorillonite has been refined to overcome uncertainties originating from different sources, which offers opportunities for addressing various health issues, e.g., cosmetics, wound dressings, and antidiarrheal medicines. Herein, three commercial montmorillonite samples were obtained from different sources and labeled M1, M2, and M3 for Ca-montmorillonite, magnesium-enriched Ca-montmorillonite, and silicon-enriched Na-montmorillonite, respectively. Commercial montmorillonite was refined via ultrasonic scission-differential centrifugation and labeled S, M, or L according to the particle sizes (small, medium, or large, respectively). The size distribution decreased from 2000 nm to 250 nm with increasing centrifugation rates from 3000 rpm to 12,000 rpm. Toxicological evaluations with human colon-associated cells and human skin-associated cells indicated that side effects were correlated with excess dosages and silica sand. These side effects were more obvious with human colon-associated cells. The microscopic interactions between micro/nanosized montmorillonite and human colon-associated cells or human skin-associated cells indicated that those interactions were correlated with the size distributions. The interactions of the M1 series with the human cells were attributed to size effects because montmorillonite with a broad size distribution was stored in the M1 series. The M2 series interactions with human cells did not seem to be correlated with size effects because large montmorillonite particles were retained after refining. The M3 series interactions with human cells were attributed to size effects because small montmorillonite particles were retained after refining. This illustrates that toxicological evaluations with refined montmorillonite must be performed in accordance with clinical medical practices.