Industrial Fly Ash Research Articles

Performance of industrial fly ash based stabilized mine haul roads under seasonal moisture changes

Mine haul roads play an important role in the mining industry. They are often designed as unsealed roads, which are frequently damaged due to seasonal moisture variation, especially when the subgrade soil is expansive clay. In this study, the performance of mine haul roads built on expansive clay soil is investigated for seasonal moisture variation using experimental and numerical investigations. Shrinkage, swelling, soil water characteristics curve (SWCC) tests, and direct shear testing were first performed to assess the hydraulic and shear performance of the control and municipal solid waste incineration (MSWI) fly ash-treated soils. The swelling reduced from 1.95 to 1.02, while the shrinkage reduced from 3.4% to 1.84% after the addition of 20% MSWI fly ash. SWCC results showed that the MSWI fly ash addition reduces the void spaces and increases residual saturation. The consolidation settlement reduced by 50% after adding 20% MSWI fly ash. The cohesion of both soil and MSWI fly ash-treated samples exhibited a bell-shaped trend with moisture increase, in contrast to friction angles which decreased with increasing saturation levels. 3D numerical models were used to predict the performance of control soil and MSWI stabilized mining haul roads using the experimental test data. The control pavement experienced increased settlement and rutting as saturation levels increased. The behaviour of the stabilized pavement differed, with the model having a 20% degree of saturation showing the least deformation due to increased stiffness from high suction. Overall, this study highlights the benefits of MSWI fly ash-based soil stabilization in improving the performance of mine haul roads under seasonal moisture changes. The findings emphasize the importance of considering the degree of saturation and stabilization techniques in pavement design to mitigate settlement and enhance overall performance.

EcoBlendNet: A physics-informed neural network for optimizing supplementary material replacement to reduce the carbon footprint during cement hydration

The addition of supplementary cementitious materials (SCMs) to cement triggers a complex chemo-physics from intricate mineral admixture interactions. This work develops EcoBlendNet, a novel physics-informed neural network (PINN), to analyze carbon emissions during SCMs-enhanced cement hydration. EcoBlendNet integrates experimental data and the chemo-physical aspects of cement hydration in a heated cement paste for various mixing blends, including Portland cement, cement-fly ash blends, and cement-slag blends. EcoBlendNet accurately predicts concrete maturity and strength, capturing early-age temperature rises. Achieving a remarkable relative L2 error of 0.03 with just 5% of training data, it facilitates efficient mesh-free analysis. The study demonstrates that transitioning from cement-blend to cement-fly ash and cement-slag blends can significantly reduce CO2 emissions without compromising strength development. Quantitative analysis suggests that replacing 45–80% of cement with industrial fly ash and slag can decrease CO2 emissions by 60–80% during cement hydration. Thus, EcoBlendNet, validated through experimentation, offers a practical and eco-friendly approach to concrete construction, bridging the gap between theory and practice.

Effect of Non-Class Fly Ash on Strength Properties of Concrete

Developing of green construction and reducing CO2emissions in the environment is a priority for industry in the coming years. Recycling fly ash in the concrete industry is a well-known way to reduce environmental impact. Aside from this benefit, there are numerous other positive effects of incorporating fly ash into concrete; however, in this research, the objective is to replace cement with a different percentage of non-class fly ash with high CaO, more than 42%. The analyzed variables are non-class fly ash properties, the effect of fly ash presence on the main properties of concrete and examining the optimum of non-class fly ash in ordinary concrete C-25/30 and high-performance concrete C-50/60. All investigations took place in the laboratory by producing 24 different mix designs and more than 1000 specimens to examine: consistency, setting time, shrinkage, and compressive strength in the short and long terms of curing. Recycling industrial waste in new construction, especially fly ash because of its non-uniform properties, still has some obstacles and is not a practical issue, but the future must be environmentally friendly, and this research proves that the objective of producing sustainable ordinary and high-performance concrete was achieved by replacing 40% of cement with non-class high CaO content fly ash. Doi: 10.28991/CEJ-2024-010-03-02 Full Text: PDF

Mechanothermal assessment of outdoors aged hybrid glass fibre reinforced polymer composite filled with fly ash as industrial waste

Industrial fly ash impregnated glass fibre reinforced polymer (GFRP) composites were examined to assess their overall characteristics in adverse ambient conditions, keeping in mind that use of filler materials in FRP composites was expected to enhance the strength properties of the material. GFRP composite specimens with 2–10 wt % industrial fly ash were fabricated in the laboratory. These were exposed to open ambient ageing for 120 days. The samples impregnated with 8 wt % fly ash and aged for 120 days were seen to absorb the minimum moisture and exhibited the maximum ILSS of 35.19 MPa and flexural strength of 690 MPa, respectively. These samples also exhibited the highest Tg of 101.53°C as revealed through low temperature DSC. It was also observed that the 8 wt% fly ash containing samples aged in the open for 120 days showed the ILSS to be 5.83% higher and Tg to be 21.95% higher as compared to the unaged GFRP samples without fly ash. FTIR spectra confirm the trend of thermo-mechanical properties. Both optical and scanning electron microscopy of the fractured surfaces of the test samples revealed the modes of mechanical failure of the hybrid GFRP composite with their indicative properties at optimized extent of fly ash dispersion.

Examining the endpoint impacts, challenges, and opportunities of fly ash utilization for sustainable concrete construction

Fly ash has been widely used as a cement substitute to improve the sustainability of concrete. Although the advantages of fly ash have been extensively documented, there is a gap in understanding why its use in mass concrete applications remains low in some countries, such as the Philippines. Thus, this work aims to understand the issues that impede waste utilization, particularly fly ash in the concrete construction industry, quantify the impact of the current practice, and identify opportunities for sustainable fly ash utilization. Endpoint impact analysis was conducted through the life cycle using SimaPro 9.3 to quantify the impacts on human health, ecosystem, and resources of 31 concrete mixtures of low, normal, and high strength design with 0 to 20% fly ash as cement replacement. In-depth, semi-structured interviews with key stakeholders were undertaken to determine the institutional, economic, social, and technological challenges related to the utilization of waste materials in large-scale concrete construction. More than 90% of the total impact of concrete contributes to damage to human health, primarily caused by global warming and fine particulate matter. The use of fly ash at 20% replacement by weight of cement benefits resources more significantly than human health and the ecosystem. The use of chemical admixture to improve strength has a significant impact on resources. High fly ash replacement for normal and high-strength concrete has a greater reduction in all endpoint categories than for low-strength design. Recommendations are proposed to maximize the beneficial impact of using fly ash in the concrete industry.

Utilization of Fly Ash Waste in the Cement Industry and its Environmental Impact: A Review

The cement industry is one of the most important industries in the development of a country. However, the production activities of the cement industry also cause significant environmental impacts, one of which is air pollution. One of the by-products of fuel combustion in the cement industry is fly ash, which if not managed properly can pollute the air and the surrounding environment. This research aims to provide an overview of the environmental impacts of using fly ash in the cement industry, especially in relation to air pollution. This research uses the literature review method, which is by collecting and reviewing literature or documents related to the research topic. The data sources used in this research are scientific journals, books, and other related documents. Data analysis in this study was carried out by reviewing and examining literature or documents related to the research topic, then summarizing and compiling the results of the analysis into an overview. Based on the results of this study, it can be concluded that the use of fly ash in the cement industry has significant environmental impacts, especially related to air pollution. However, there are several technologies and fly ash processing methods that can reduce the environmental impact of cement industry production activities, such as the use of fly ash as raw material for making lightweight concrete or as raw material for the production of other building materials.

Effect of Class F Fly Ash on Strength Properties of Concrete

Reducing the amount of CO2 emissions in the environment is one of the priorities of the EPA and other environmental agencies. A way to reduce CO2 emissions is by using fly ash in the concrete industry. Aside from environmental benefits, fly ash has numerous quality advantages; some of the positive effects were recognized earlier; however, in this research, the objective is to replace cement with a different percentage of class F fly ash with a low CaO content to produce sustainable concrete. Laboratory tests were performed to examine the rational percentage of cement replaced by class F fly ash in ordinary concrete C–25/30 and high-performance concrete C–50/60. In total, twelve different mix designs were prepared to examine consistency, setting time, shrinkage, and compressive strength in different periods of curing for more than 600 days. Using recycled material in new buildings still has some obstacles, but the future of construction must be green, so this research indicates that the objective of producing ordinary and high-performance concrete was achieved by replacing 30% of cement with class F fly ash. Doi: 10.28991/CEJ-2023-09-09-011 Full Text: PDF

First evidence of industrial fly-ash in an Antarctic ice core

Spheroidal carbonaceous particles (SCPs) are a component of fly-ash, the particulate by-product of industrial high temperature combustion of fuel-oil and coal-series fuels. We provide the first evidence that these indelible markers of industrialisation have been deposited in Antarctic ice, thousands of kilometres from any potential source. The earliest observed particle was deposited in an ice layer from 1936 CE. While depositional fluxes are low, chemical analysis of individual SCPs indicates a coal combustion origin.

Qualitative and quantitative analysis for Cd2+ removal mechanisms by biochar composites from co-pyrolysis of corn straw and fly ash

Removal of heavy metals (e.g., Cd) from contaminated water using waste-converted adsorbents is promising, but the efficiency still needs to be improved. Here, we prepared a functional biochar composite as novel Cd adsorbents by co-pyrolysis of two typical solid wastes, i.e., agricultural corn straw and industrial fly ash. The adsorption behavior and mechanism were investigated using batch and column adsorption experiments and modern characterization techniques. Results showed that alkali-modified fly ash (AMFA) was loaded onto the surface of the corn straw biochar as some fine particle forms, with quartz (SiO2) and silicate being the main mineral phases on the surface. The maximum sorption capacity fitted by Langmuir model for functionalized biochar composite (FBC700) was up to 137.1 mg g−1, which was 7.7 times higher than that of the original corn straw biochar (BC700). Spectroscopic analysis revealed that adsorption mechanisms of Cd onto the FBC700 included mainly precipitation and ion exchange, with complexation and Cd-π interaction also contributing. The AMFA could effectively improve the mineral precipitation with Cd. The adsorption columns filled with FBC700 exhibited a longer breakthrough time than that filled with BC700. The adsorption capacity calculated by Thomas model for FBC700 was also approximately 6.0 times higher than that for BC700, showing that FBC700 was more suited to practical applications. This study provided a novel perspective for recycling solid wastes and treating Cd-contaminated water.

Conservation of waste melon shell and fly ash utilized as reinforcements for aluminum alloy matrix in terrestrial ecosystem acquired green hybrid composites

AbstractNowadays, the environmental ecosystem is protected and maintains sustainability for waste material management like agriculture product end waste and industrial waste. The main scope of this research is to gather the agriculture end product of melon shell ash waste and industrial fly ash waste utilized as organic reinforcements for making a lightweight with superior strength green hybrid composite for fourth‐generation terrestrial ecosystem applications. The various volume percentage of waste melon shell ash and fly ash are governed by the ratio of 0:0, 1:4, 2:4, 3:4, and 4:4, respectively. The green aluminum alloy (Al6061) hybrid composite is synthesized via a semi‐solid stir technique. The developed green hybrid composites are subjected to physical and mechanical studies followed by ASTM standards. The developed composite contained a 4:4 ratio of melon and fly ash and found a light weight of 2.75 ± 0.11 g/cc with improved tensile strength and hardness percentages of 8.35% and 21.38% compared to cast aluminum alloy. This research may help basic knowledge for future investigations on modern green composite manufacturing via agricultural and industrial wastage.

Utilization of ground granulated blast-furnace slag powder in brick industry: A new generation building material

This study presents research on the use of geopolymer bricks in construction, which are made using materials such as fly ash, GGBS, sand, cement, and alkali activators. The study focuses on the use of GGBS as a fractional replacement for cement in the bricks and investigates the effects of different molarities and silicate-to-hydroxide (S/H) ratios on the properties of the bricks. The results show that the bricks made with a molarity of 10 M and S/H ratio of 2.5 had the highest compressive strength of 27.22 MPa. The study suggests that using geopolymer bricks is a more environmentally friendly and cost-effective option than traditional fly ash or burnt clay bricks in the construction industry.

Nickel oxide scale microstructure and accelerated growth in combustion flue gas: Effect of ash particles

Model Ni-25Cr and Ni-25Cr-2Mn-1Si (wt%) alloys coated with an industrial fly ash were exposed to a wet CO2 gas at 750 °C. It was found that the outer thermally-grown NiO scale encapsulated ash particles at an accelerated rate. TEM combined with TKD analysis revealed that nano structured NiO grains on the ash surface contributed to the observed NiO encapsulating effect.

Cost-Effective Utilisation of Industrial Fly Ash Waste in Treatment of Domestic Wastewater

In the present research an economically effective porous fly ash-based filter candle (FFC) was developed for the treatment of domestic wastewater using fly ash, sodium silicate, wood dust, silica fume and water. The four testing specimens of FFC having different sizes (10, 20, 30, and 40 mm) were prepared. The parameters such as turbidity, total suspended solids (TSS), dissolved oxygen (DO), total dissolved solids (TDS), and pH of domestic wastewater were studied before and after treatment. The test results showed that there is a decrease in values of turbidity from 7 to 5.9 NTU, TSS from 300 to 218 mg/L, TDS from 400 to 302 mg/L, pH from 10.6 to 7.9, and BOD from 9.5 to 7.9 while DO values decreased in the range of 8.9 to 7.7. The observed porosity, compressive strength, and flow rate of FFC fall in the range of 24.55-27.26 %, 1.5-2.3 MPa, and 180-290 ml/h, respectively. The filtration tests using FFC exhibited good performance with >92 % filtration efficiency. Overall results have shown that FFC having a 30 mm bed thickness is recommendable for effective wastewater treatment. Thus, an attempt has been made to introduce a novel technology for domestic wastewater treatment using industrial fly ash waste.

Constructing a greener future: A comprehensive review on the sustainable use of fly ash in the construction industry and beyond

An industrial by-product known as fly ash has several possible uses, especially in the building sector and others. Fly ash is used as a cement substitute in blended cement or concrete and is valued for its potential advantages, including greater structural strength, cost efficiency, and environmental sustainability. The distinctive particle size properties of fly ash, which support its adaptability and affordability, are important factors considered in this work. This work explores the inherent qualities of fly ash that can advantageously contribute to cement mortar and concrete compositions by a thorough investigation of various scientific literature, which includes empirical studies, case studies, and review articles. The analysis was conducted under the presumption that these advantages can be significantly increased with the right amount of fly ash. Findings demonstrated that structural concrete components need to be properly cured in both friendly and hostile circumstances. There is evidence that fly ash can boost strength to a certain extent, with a 30% fly ash mix being ideal for normal loading and a 20% fly ash mix for more difficult circumstances. Improved workability, lower heat of hydration, increased resistance to sulphate assaults, and stronger weather resistance are further noteworthy benefits. Fly ash is an essential component of sustainable construction since it complies with ASTM, LEED, and building code criteria. This study also looked at the numerous uses of fly ash outside of the building industry, emphasising its potential in industries including agriculture, soil stabilisation, and the manufacture of lightweight building materials. Future research into the creative application of fly ash in the Indian building industry appears to be quite promising. Last but not least, this investigation highlighted how employing fly ash has important environmental advantages, such as having the capacity to lower CO2 emissions, control the greenhouse effect, and lessen environmental contamination.

Preparation of NaA and NaY zeolites from kaolin and their use as adsorbent for the removal of Ni2+ and Co2+ in aqueous solution

Heavy metal ions can cause environmental problems and affect human health if they are not properly removed before waste water released into the environment. Adsorption is one of the most widely used method for removal of heavy metal ions due to its simplicity and efficiency. Among many adsorbents, NaA and NaY zeolites showed good ability to remove metal ions in aqueous solution due to their high ion exchange capacity. However, the cost of zeolites NaA and NaY, synthesized from pure chemical sources, is still quite high. Therefore, this paper presented the synthesis of NaA and NaY from kaolin, a commercial available and cheap material. Experimental results showed that kaolin calcined at 500°C was appropriate to be used as and source for synthesis of zeolite. NaA and NaY zeolites were synthesized by reaction at 100°C in 24 hours. NaA zeolite was synthesized in a gel with the molar ratio in term of 1.0 Al2O3/2.0 SiO2/1.6 Na2O/76 H2O and NaY zeolite was synthesized with the molar ratio of 1.0 Al2O3/3.7 SiO2/2.7 Na2O/76 H2O with the addition of from industrial fly ash. XRD results of both synthesized NaA and NaY zeolites showed that the diffraction peaks of these zeolites matched with simulated XRD pattern of NaA and NaY zeolite. Synthesized NaA and NaY zeolites were used as adsorbents to remove Ni2+ and Co2+ in aqueous solution. NaY zeolite showed the highest adsorption capacity of 56.5 mg/g and 58.2 mg/g for Ni2+ and Co2+, respectively. NaA zeolite showed higher metal removal efficiency than that of NaY zeolite, with the highest adsorption capacity for Ni2+ and Co2+ at 80 mg/g and 123.2 mg/g, respectively. Experimental data fit the pseudo-second-order model and Langmuir isotherm adsorption model well. The results showed that the removal of Ni2+ and Co2+ ions by NaA and NaY zeolites was of the .

Assessment of hazardous radionuclide emission due to fly ash from fossil fuel combustion in industrial activities in India and its impact on public

Traditionally coal has been extensively used as a dominating fossil fuel in a wide range of industries due to its abundance. In India, industries like thermal power plants, cement industries, iron, and steel industries along with many captive power plants consume a huge quantity of coal each year to meet energy demand. Coal combustion releases blackish-grey colored fly ash waste is one of the most imperative sources of radionuclides like Radium (226Ra), Thorium (232Th), Potassium (40K) and Uranium (238U). The estimated industrial fly ash is ∼308.416 Million Tonnes (MT) in 2019, considered as an emerging environmental problem. This study represents the first-ever radionuclide emission from Indian fly ash generated across various major industries. The results reveal that the estimated 226Ra, 232Th, 238U, and 40K radionuclides were estimated to be ∼27.473 TBq, ∼44.351 TBq, ∼41.089 TBq, and ∼111.091 TBq respectively. The potential radionuclide hotspot regions across the nation are identified, which could be used as an important tool to assess its impact on the chronic exposure of millions of residents living near these sources. Cleaner or green energy could be the best alternative to combat the unseen health disaster. More effective and safe utilization of fly ash can minimize the hazardous effect of radionuclides emission.

An experimental study on cement concrete with industrial fly ash and Phosphogypsum

Industrial Flyash (IFA) is a fine powder made from non-combustible materials and a residue of carbon from incomplete combustion. Phosphogypsum (PG) is also a solid by product of phosphoric acid processing, which is employed in a variety of fertilisers and chemicals. Traditional construction material manufacturing processes destroy the earth's vital natural resources. Furthermore, IFA and PG is a solid waste, which is frequently dumped in open spaces. IFA and PG contains natural mineral which can be used as admixture in concrete. It can be used as partial replacement to the cement in the concrete up to certain limit. The experimental findings include compressive strength (CS), flexural strength (FS) and split tensile strength (STS) by partially cement replacement with Industrial IFA and PG employing 0 %, 5 %, 7.5 %, 10 %, 12.5 %, 15 %, and 20 % on M40 grade concrete and water-binder ratios of 0.45. The CS is determined by testing cube specimens for 7 and 28 days, as well as FS and STS is found by testing the beams and cylinders specimens for 7 and 28 days respectively. The optimal proportion shows maximum strength at 15 % IFA and 7.5 % PG respectively. Further increase in percentage, strength of concrete decline marginally. 10 % substitution of cement with IFA + PG (combined 50 % each) used shows the optimal proportion to achieve maximum strength, and further increase in IFA and PG causes a decrease in strength. The addition of IFA and PG increases the amount of water required due to increase in fine particles or a bigger surface area. When compared to the control mix, the workability of concrete with IFA and PG reduces slump value by up to 15 %.44Corresponding Author: E-mail address: sandeepsatheresearch@gmail.com (Sandeep Sathe)

Li4SiO4 adsorbent derived from industrial biomass fly ash for high-temperature CO2 capture

In recent years, biomass derived Li4SiO4 adsorbent has attracted increasing attentions in the field of post-combustion high-temperature CO2 capture. In this work, for the first time, industrial fly ash collected from the biomass boiler was employed to produce Li4SiO4 adsorbent. In addition, ash pretreatment methods including water-washing and acid-washing were also carried out to promote the performance of derived adsorbent. By evaluating the physicochemical properties as well as the CO2 capture capacity of these adsorbents, it is concluded that the industrial biomass fly ash is feasible for the production of Li4SiO4 with a reasonable CO2 adsorption capacity of ∼0.243 g/g. It is further found that the acid-washing could remove the majority of impurities inside fly ash and increase the purity of derived adsorbent, resulting in a superior capacity as high as ∼0.358 g/g. However, in comparison with lab-scale obtained biomass ash, the industrial biomass fly ash contains more water-insoluble impurities, and thus the secondary element removal effects of water-washing pretreatment were significantly inhibited. The above findings could provide guidance for the future scale-up production of biomass derived Li4SiO4 adsorbents for practical carbon capture applications.

Enhancing flotation removal of unburned carbon from fly ash by coal tar-based collector: Experiment and simulation

The unburned carbon (UC) in fly ash is a vital parameter that governs the further utilization of fly ash in mortar and concrete industry. Flotation is an effective methodology for removing the UC from fly ash. However, the specific physicochemical properties of the UC particle surface make them difficult to float. In this study, a coal tar-based (CTB) collector was used to remove the UC from fly ash through flotation process. The adsorption mechanism of the CTB collector and diesel on the UC particle surface was characterized by scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), molecular dynamics (MD) simulation, and induction time tests. The levels of oxygen-containing functional groups and aromatic ring compounds present in the CTB collector were considerably higher than those in diesel. The oxygen-containing functional group contents on the untreated UC surface, the diesel-treated UC surface, and the CTB collector-treated UC surface decreased in that order. The MD simulation results indicated that the aromatic compounds (dibenzofuran and naphthalene, etc.) in the CTB collector interacted strongly and adsorbed at deep locations with the UC surface compared to the alkanes (dodecane, diesel, etc.). The alkanes are indispensable as the collector in the fly ash flotation process and synergize with aromatic compounds to improve the mobility of water molecules on the UC surface. The CTB collector significantly enhanced the floatability of the UC particle and hence improved the flotation removal of UC from fly ash.

Remarkable enhancement in dielectric constant and band gap shrinkage of hydrothermal grown fly ash waste derived zeolite nanoneedles

Highly crystalline zeolite nanoneedles were synthesised using industrial fly ash waste particulates using hydrothermal method for the first time. X-Ray diffraction result confirmed the formation of 13X crystalline zeolite nanoneedles. Elemental analysis of zeolite was investigated using X-Ray fluorescence spectroscopy technique. HR-TEM exhibits the crystalline nanoneedles like morphology with length of 50–300 nm and diameter of 30–40 nm. In, UV-ViS study, absorption cut-off band at 264 nm and optical band gap of 2.8 eV were obtained. The zeolite nanoneedles exhibits high refractive index of 4.5 at 264 nm. Ultra high electrical dielectric constant of 99151 was observed at low frequency of range 30 Hz. Such high dielectric constant of fly ash derived zeolite nanoneedles was almost 2450 times higher than bulk zeolite. Our results demonstrate a green synthesis method of zeolites nanoneedles from fly ash. The present finding shows its potential application in charge storage, optoelectronics devices and molecular sieving.