Utilization Of Fly Ash Research Articles

Using solid waste to treat wastewater: Preparation of flowerlike calcium silicate hydrate from coal fly ash for cadmium removal

Efficient utilization of Coal fly ash (CFA) and ingenious treatment of cadmium (Cd (II)) in the water environment are interesting topics. In this paper, a mesoporous floral calcium silicate hydrate (MCSH) for removal of Cd (II) was prepared by low temperature hydrothermal synthesis using CFA desilication solution. Different synthesis parameters (molar ratio of Ca to Si (Ca/Si), temperature, time) of MCSH were investigated and optimized. All synthesized MCSH showed good adsorption properties for Cd (II), and MCSH synthesized at Ca/Si molar ratio of 1.0, temperature of 363 K and time of 120 min had the optimum Cd (II) adsorption capacity of 357.43 mg/g. The effects of solution pH, MCSH dosage, coexisting cations and ionic strength on the Cd (II) adsorption performance by MCSH were further considered systematically. The adsorption process was a spontaneous and endothermic process, conformed to the pseudo-second-order kinetic and Langmuir isothermal model. The main mechanism of Cd (II) removal by MCSH was the precipitation between Cd (II) and OH– released by MCSH, accompanied by ion exchange, surface complexation and electrostatic adsorption. The mesoporous flowery MCSH prepared from CFA provides an satisfactory solution for the utilization of solid waste resources and the purification of heavy metal wastewater.

Pengaruh Campuran Kawat Bendrat pada Karakteristik Beton dengan Subtitusi Fly Ash pada Nilai Slump

The increasing use of concrete in the construction world encourages massive exploitation of the environment that has limestone or karst reserves to be used as the main raw material for making cement, to reduce the excessive use of cement, a way is used to utilize fly ash as a substitute for part of the cement in the concrete mixture to reduce the negative impact of limestone mining activities as well as cement production which contributes a total of 9% of CO2 emissions on earth. In this study, bendrat wire will also be added to determine the workability of fresh concrete mixes. From the results of the study it was found that concrete with fly ash substitution without bendingt wire mixture got an average height of 10.7 cm, while the variation with the addition of bending wire at 3% decreased in the average slump value to 10 cm where the increasing percentage of bending wire made the average slump value go down, seen in the 6% and 9% variations which experienced a decrease in the average height of the slump with a height of 9.7 cm and 9 cm, this can have an impact on the workability of the concrete mix itself, with a higher percentage of bending wire will have difficulty when applying to building construction.

Aminated Spherical SiO2 Synthesized from Fly Ash and Its Application for Pb2+ and Cu2+ Sorption

Fly ash was utilized as raw material for the preparation of spherical SiO2 (SS), which was subsequently ammonified using APTES (H2NCH2CH2CH2Si(OC2H5)3) to obtain aminated spherical SiO2 (SSN). The physicochemical properties of SS and SSN were systematically characterized. Notably, SS exhibited a remarkable specific surface area and pore volume, enabling it to accommodate abundant nitrogen-containing groups. These functional groups served as crucial active sorption sites, significantly enhancing the sorption capacity of SiO2 for Pb2+ and Cu2+ ions. Thus, the removal efficiency was above 99.9% when using dosages of 4 and 6 g/L SSN in solutions containing 200 mg/L of Pb2+ and Cu2+, respectively. Additionally, SSN showed a higher theoretical maximum sorption capacity for Pb2+ and Cu2+ ions, as determined by the Langmuir isotherm model, with values of 185.2 mg/g and 86.2 mg/g, respectively. These results surpass those reported in previous studies on adsorbents derived from fly ash. The chemical reactions that occurred between the aqueous cations and nitrogen-containing groups were identified as the pivotal factors governing the sorption of Pb2+ and Cu2+. This study presents a practical approach to fly ash utilization, along with the effective removal of Pb2+ and Cu2+ from water.

Thermodynamic simulation study on compression ignition engine operating with oil obtained via catalytic pyrolysis of waste polythene covers

In recent years, waste-to-energy systems are receiving more attention due to their dual benefit of reduction of pollution caused by waste materials and reducing the overconsumption of fossil fuels. Since plastic waste is readily available and has a high heating value, it is a viable source of energy.; plastic garbage makes an excellent source of energy. Today, a feedstock made up of several types of plastic is used to quickly pyrolyze and produce plastic pyrolysis oil (PPO) or waste plastic oil (WPO). The oil could be utilized in internal combustion engines to produce heat and power. In the current work, waste polythene covers were transformed into value added products by utilizing fly ash catalyst and oil obtained is examined for suitability to run in the diesel engine. In the primary phase simulation study is performed on a four-stroke single cylinder DI Compression ignition engine using Diesel-RK engine simulator, results indicated that, waste plastic oil was found to emit higher oxides of nitrogen compared to diesel therefore in the secondary phase the same engine simulated by implementing exhaust gas recirculation at 3.5 %,7 %,10.5 % and 14 % rates. In the end engine parameters get optimized using 3D parametric optimization technique.Simulation Results indicate that, performance parameters such as brake power, brake thermal efficiency and brake specific fuel consumption were found to be decreased slightly under EGR conditions. Furthermore, combustion parameters such as cylinder peak pressure and peak temperature decrease up on implementing the exhaust gas recirculation, similarly the emission characteristics such as CO2, PM and smoke found to be increase with increase in EGR ratio while oxides of nitrogen emissions significantly decreased under EGR conditions. In order to reduce the emissions further, a 3D parametric optimization technique was adopted and optimal results obtained when engine runs at compression ratio of 16.5, injection timing of 19.38 and EGR percentage of 4.8 %.

REVIEW ON PRODUCTION AND UTILIZATION OF FLY ASH: AN INDIAN PERSPECTIVE

A rapidly developing economy creates surge in energy demand and forced to find various alternative energy sources. Though many non-conventional energy sources have come up in the energy landscape, the t dependency on coal-based energy has not been reduced. Continuous coal burning generates huge quantity of Fly Ash and creates problems of storage, transportation, and management for power plants. If the fly ash generated is not handled properly, it poses a serious threat to ecology and the environment. The present study begins with focusing on the importance of coal in the Indian energy sector and discuss the status of fly ash generation and utilization throughout the years. It also focuses on how enforced laws and regulations help for management of fly ash. It emphasizes fly ash classification and physical-chemical characteristics, then, elaborates on the different sectors that have adopted fly ash as resource material and proven its worth over a time. This review attempts to highlight the current status of fly ash management in India which contributes to environmental and natural resources conservation.

Development and performance evaluation of sustainable lightweight cement composites utilizing fly ash and waste soil

Development and performance evaluation of sustainable lightweight cement composites utilizing fly ash and waste soil

WEAR RESISTANT OF CACO3/FLY-ASH CERAMIC MATRIX COMPOSITE

This study aimed to investigate the potential of utilising fly ash, a harmful byproduct of coal waste, in the manufacturing of composite materials to reduce its environmental impact. Calcium carbonate (CaCO3) and fly ash were mixed with zinc stearate using the powder metallurgy method to create wear-resistant samples. The compaction load was adjusted to achieve optimal low-pressure compaction, with pressures of 22.75 MPa, 23.45 MPa, 24.14 MPa, and 24.83 MPa used for single punch pressing. After 10 minutes of holding time, sintering was conducted at 900 OC for 1 hour. The raw materials were tested using X-ray diffraction (XRD) and sieved based on the mesh size. The composite was characterised through various tests, including density testing, wear testing, and scanning electron microscopy (SEM) to observe the microstructure. The density value increased with the compaction load, with a maximum apparent density of 1.794 g/cm3 and the highest porosity percentage at a pressure of 22.75 Mpa of 31.155%. Furthermore, the specific wear value decreased as the compaction load increased, with the lowest specific abrasion value of 1.17 x 10-6 mm2/kg. Therefore, using fly ash to produce composite materials is a promising solution to reduce the negative impact of coal waste while producing wear-resistant materials.

Adsorption Potential and Mechanism of Sludge-Based Activated Carbon Modified with Fly Ash for Removal of Heavy Metals

The treatment of sludge has received a lot of attention due to its intractable status and potential resource value. In order to explore methods of sludge resource utilization and to reduce the harm of heavy metals in municipal sewage, this study analyzed the preparation method of a modified sludge adsorbent (MSA). Another common waste (fly ash) was added to raw domestic sludge (RDS) in a certain proportion and developed to have the ability to adsorb heavy metals through multiple steps such as drying, mixing, activation and carbonization. The adsorption performance of the modified sludge adsorbent (MSA) was verified by simulating wastewater containing Cu2+ and Cd2+, and the surface and structural properties were studied from a microscopic perspective with the aid of SEM and XRD. This study showed that the MSA was characterized by increased microporosity, an enlarged surface area and enhanced activity of functional groups, and the best performance for heavy metal adsorption was found when the RDS was mixed with fly ash at a ratio of 4:3 and a pH of 8. The highest removal rates for the heavy metals Cu2+ and Cd2+ were 99.6% and 99.7%, respectively. The adsorption kinetics and adsorption isotherms indicated that the adsorption behavior of the MSA was controlled by both physical and chemical adsorption, and the best fit of the Langmuir adsorption isotherm model revealed the predominance of monolayer adsorption. The present study is a meaningful exploration of the resource utilization of sludge and fly ash and can provide a cheaper and more effective material for addressing heavy metal pollution in domestic sewage.

Utilization of Fly Ash and Bottom Ash Waste of PLTU Jeranjang on Geopolymer Paving

Waste is produced as fly ash and bottom ash from coal-fired power stations. PLTU in West Nusa Tenggara uses 13,000 tons of coal in one month, so it can be estimated that Fly Ash waste will be produced around 1,950-2,210 tons. Geopolymer concrete utilizes fly ash as an adhesive to replace Portland cement. Fly ash is used to make geopolymer concrete, which is created by polymerization reactions caused by alkali-aluminosilicate reactions that result in materials with strong structures. In this study, the ratio of the composition of the weight ratio of paste (fly ash and alkaline solution) with aggregate was 35:65. The aggregates used are sand and bottom ash. The test object is a prototype paving block with a specific dimension of 10cm x 21cm x 6cm. Mechanical testing using compressive strength and water absorption testing with a specimen life of 7, 14, 21, and 28 days. Testing of bottom ash and fly ash characteristics in the form of XRF testing. The XRF test results found that the bottom ash and fly ash of PLTU Jeranjang belonged to class F. The average test result of compressive strength at the age of 28 days for mix designs A, B, and C was 8.54 MPa, respectively; 10.29 MPa; and 16.10 MPa. Quality geopolymer paving can be applied to gardens and other interiors used. Another result of the absorption value of Mix design C of 8% shows the addition of fly ash can be utilized in place of some of the used cement in paving blocks that satisfy SNI 03-0691-1996 Quality C criteria.

Synthesis and Surface Strengthening Modification of Silica Aerogel from Fly Ash.

This study focuses on using activated fly ash to preparate silica aerogel by the acid solution-alkali leaching method and ambient pressure drying. Additionally, to improve the performance of silica aerogel, C6H16O3Si (KH-570) and CH3Si(CH3O)3 (MTMS) modifiers were used. Finally, this paper investigated the factors affecting the desilication rate of fly ash and analyzed the structure and performance of silica aerogel. The experimental results show that: (1) The factors affecting the desilication rate are ranked as follows: hydrochloric acid concentration > solid-liquid ratio > reaction temperature > reaction time. (2) KH-570 showed the best performance, and when the volume ratio of the silica solution to it was 10:1, the density of silica aerogel reached a minimum of 183 mg/cm3. (3) The optimal process conditions are a hydrochloric acid concentration of 20 wt%, a solid-liquid ratio of 1:4, a reaction time of two hours, and a reaction temperature of 100 °C. (4) The optimal performance parameters of silica aerogel were the thermal conductivity, specific surface area, pore volume, average pore size, and contact angle values, with 0.0421 W·(m·K)-1, 487.9 m2·g-1, 1.107 cm3·g-1, 9.075 nm, and 123°, respectively. This study not only achieves the high-value utilization of fly ash, but also facilitates the effective recovery and utilization of industrial waste.

Potential Optimization of Industrial Waste as an Alternative Material for Composite Filler in Brake Pad Manufacturing – A Review

This study investigates the sustainable utilization of fly ash, palm slag and Cement By-Pass Dust (CBPD) waste as alternative materials for environmentally friendly brake pad development. These waste materials, with compositions similar to Asbestos, historically used in brake pad composites, present an eco-conscious solution. Integrating industrial waste in brake pad production offers substantial environmental benefits, technological progress, and commercial advantages. The compaction value and particle size distribution significantly impact brake pad mechanical properties. Adjusting these factors is crucial for meeting desired mechanical property requirements. A large particle size distribution enhances material density and hardness poses challenges in maintaining performance stability at high temperatures despite good recovery values. This paper highlights the potential of waste materials for sustainable brake pad development and underscores the need for careful optimization for high-temperature stability.

Formulation determination and performance study of high-volume fly ash-based grouting fire extinguishing materials

Considering the continued advancement of China's industrial sector, a substantial quantity of circulating fluidized bed fly ash (CFBFA) and calcium carbide slag (CS) is generated throughout the production process. Considering the rich calcium content inherent in CFBFA (circulating fluidized bed fly ash) and the inherently alkaline nature of CS(carbide slag), the amalgamation of these two constituents leads to a multitude of hydration reactions, culminating in the synthesis of polymeric grouting materials. This study undertaked a comprehensive examination and regulation of three factors within the binary system: water-cement ratio, CS content, and CS particle size. Through the utilization of scanning electron microscopy (SEM), X-ray diffraction (XRD), and (TG) thermogravimetric analysis, the investigation aims to elucidate the influence mechanism of the composite gelling system comprising fly ash and calcium carbide slag on the compressive strength, setting time, and other pertinent indicators of grouting materials. The data reveals that when the water-cement ratio is set at 0.85, CS content at 30%, and CS ball milling time at 1 h, the resulting grouting material exhibits a fluidity of 279 mm, a water separation ratio of 3.13%, and achieves a strength of 15.6 MPa at 28 days. It boasts a stable and easily transportable slurry, which possesses a certain degree of cementitious performance, effectively sealing off any air leakage channels. Moreover, by subjecting CS to appropriate pre-treatment measures, a suitable quantity of active silicon and aluminum elements can be thoroughly dissolved within the CFBFA (circulating fluidized bed fly ash) slurry system, giving rise to a staggered distribution and dense hydration product structure. Considering the requirements for gangue mountain fire extinguishing slurry, a CFBFA-CS based grouting material formula has been carefully selected. Additionally, simulation grouting fire extinguishing experiments have demonstrated that the injection of the slurry is highly effective in reducing the temperature of the combustion test block, isolating oxygen, and lowering the temperature within the combustion zone. After 5 h, the temperature drops to below 100 °C, and no re-ignition phenomena are observed. The outcomes of this research can provide valuable scientific guidance for the development of high-performance fire extinguishing grouting materials utilizing fly ash and carbide slag.

Fly Ash from Coal Power Plants and its Application - a Step Towards Green Building

The utilization of fly ash, a byproduct from thermal power plants, in construction materials such as concrete, mortar, bricks, asphalt mixes, and binders for stabilization offers significant environmental and economic benefits. This comprehensive technical review delineates the historical background, current applications, and future potential of fly ash in reducing the construction industry's carbon footprint, particularly in Serbia. It outlines the successful integration of fly ash in various construction scenarios, emphasizing its role in enhancing material properties while contributing to sustainability by repurposing industrial waste. The document further explores the environmental advantages of fly ash use, highlighting its impact on lowering the carbon emissions associated with traditional cement and aggregate production. Through a detailed comparison of carbon footprints, the text argues for the adoption of fly ash in construction practices as a pathway towards achieving a carbon-neutral future. The discussion on the variable CO2 footprint of fly ash, influenced by production methods, underlines the importance of optimizing these processes to fully leverage its environmental benefits. This review underscores the need for the construction industry to embrace fly ash as a key component in materials, aiming for both performance improvement and sustainability, aligning with global efforts towards a CO2-neutral environment.

Proficiency Testing Program for Fly Ash: Ensuring Quality and Consistency Through Standardized Evaluation

This case study evaluates a Proficiency Testing Program (PTP) for fly ash testing, focusing on the homogeneity, stability, and performance of participating laboratories. The study aims to identify areas for improvement in testing methodologies to enhance the reliability of fly ash analysis. The PTP adheres to international standards, including ISO 13528:2015 and ISO/IEC 17043:2010, for sample preparation, testing, and data analysis. The PTP ensures the homogeneity of test samples through meticulous division, testing, and data-driven analysis. The stability of samples is monitored through regular tests at predetermined intervals, with results compared to initial homogeneity tests. The methodology of evaluation involves calculating Z' (z-prime) scores to assess the performance of participant laboratories, with scores within ±2.0 considered satisfactory and scores beyond ±3.0 considered outliers. The results of the proficiency testing reveal variations in the performance of participant laboratories across specific gravity, fineness, compressive strength at 7 days, and soundness by autoclave parameters. While most laboratories demonstrate adherence to expected values, some deviations raise concerns and highlight the need for continuous improvement. Laboratories with deviations are encouraged to evaluate their testing methodologies and address factors contributing to the observed deviations. Overall, the study underscores the importance of proficiency testing in ensuring the quality and consistency of fly ash testing. Continued development and refinement of proficiency testing programs are essential for the sustainable utilization of fly ash in various applications.

Unraveling the environmental and economic impacts of fly ash utilization on mass concrete considering industry practices

Unraveling the environmental and economic impacts of fly ash utilization on mass concrete considering industry practices

Development of a Low-Density Waste-Based Geopolymer Construction Material

The construction industry, integral to national infrastructure development, faces environmental challenges attributed to Portland cement’s high energy consumption and carbon dioxide emissions during production. To address this challenge, this study integrated waste fly ash and polystyrene into geopolymers to enhance environmental sustainability and economic feasibility. The objectives included developing low-density geopolymers using polystyrene inclusion, optimizing component mixing ratios, assessing activator concentration effects, determining the optimal curing conditions, and characterizing the resulting geopolymers. Through experimental investigation, low-density geopolymers were developed with optimized component ratios and curing conditions. The experimental procedure began with the classification of fly ash to determine its suitability for various applications, revealing it to be type F. Geopolymers were fabricated using a mixture of fly ash, water, sodium hydroxide activator, and polystyrene. Varied concentrations of sodium hydroxide and polystyrene were employed. Two curing temperatures, 60 °C and 100 °C, were explored. The results showed that greater sodium hydroxide concentrations improved the structure and compressive strength of the geopolymers. The results also demonstrated a significant correlation between the curing conditions and the mechanical properties of the produced geopolymers. The goal of reducing the density of the geopolymers for lightweight thermal-resistant applications was achieved through polystyrene incorporation. However, polystyrene incorporation negatively impacted the compressive strength. The optimum production conditions for the sodium hydroxide-varied samples were 8 g sodium hydroxide/g sample cured at 100 °C, while the optimum production conditions for polystyrene-varied samples were 1 g polystyrene/g sample cured at 60 °C. The findings confirmed the viability of utilizing fly ash and polystyrene wastes to produce sustainable, low-density, thermal-resistant construction materials. Overall, increasing activator concentration enhances the strength and durability of geopolymers, while polystyrene contributes to the development of lightweight geopolymers, provided the appropriate amount is utilized. To ensure replicability, the formulation procedure and input quantities must be tailored according to the intended geopolymer application. These insights offer practical guidance for optimizing geopolymer manufacturing processes towards enhanced sustainability and performance.

Effective use of Waste Materials: A Case Study of Utilization of Fly Ash in Flexible Pavement Structures

Generation of energy through thermal processes is still dominant in many parts of the world. One of the by-products of this process is fly ash, whose safe disposal incurs monetary and environmental costs. To mitigate this issue, utilization of fly ash, as a construction material, has been increasing remarkably; however, evaluation and summarization of its use in pavement construction are not very common. This study reviews its utilization in construction from different aspects and attempts to fill the gap within the literature with a critical review of fly ash usage in pavement construction engineering for the last few decades. Further recommendations have also been suggested in this context. Class ‘C’ fly ash is used for soil stabilization and class ‘F’ is used in concrete. Review of the literature found the following results. Application of fly ash, in both flexible (asphalt) and rigid (concrete) pavement, is common in the form of a filler material. However, this paper only focuses on its use in flexible pavement layers. In the case of flexible pavement, fly ash is used can be used in surface, base, and sub-grade layers. The surface layer is made up of concrete, wherein it can be used as mineral filler or partial replacement of asphalt. The most common types of test performed on asphalt concrete are Marshall stability and tensile strength. However, there is a lack of field testing studies on asphalt concrete modified with fly ash. As for the other layers of flexible pavement, fly ash has been used with activators for their stabilization as these layers are made up of natural compact materials. Fly ash has shown promising results when used with cement, with both used within a proportion of 10%. The future research areas, identified through this review, are modeling of pavement layers modified with fly ash, and standardization of fly ash properties for use in pavement layers.

Recovery of Zn and Cu from municipal solid waste incineration fly ash by integrating ammonium leaching and ammonia removal

This study introduces an environmentally friendly process for recovering zinc (Zn) and copper (Cu) from municipal solid waste incineration (MSWI) fly ash using ammonium chloride leaching and ammonia removal. The leaching rates for Zn and Cu were 54.39% and 86.23%, respectively, with total recovery rates reaching 52.21% and 85.28%, respectively. The recovered precipitate demonstrated significant Zn (33.62%) and Cu (14.19%) contents, making it ideal for metal smelting. The ammonium leaching process also showcased effective reduction and dechlorination effects on the fly ash. The treated fly ash had a reduced mass of only 30.63% of the original, and chlorine content decreased from 26.23% to 0.84%. The results of this study support the sustainable utilization of MSWI fly ash by facilitating valuable resource recovery and promoting its conversion into construction materials.

Research on the brightening effect of miscible wetting additives on fly ash coatings

Abstract The resource utilization of fly ash has always been a popular topic in the field of solid waste recycling. This paper is based on the three-phase reaction system of “fly ash (s)-[Ca(OH)2–H2O/ethanol] (l)-CO2 (g)”, using the bubble carbonization method to carry out heterogeneous phase reaction with fly ash as the core crystallized to form a fly ash-based calcium carbonate composite with higher brightness. The composite material is used in the filling of paper instead of calcium carbonate filler. Based on the previous research of our team, we focused on exploring the addition of miscible wettability additives (ethanol and acetone) to improve the wettability of the reaction system, thereby improving the whitening and modification effect of fly ash. The results showed that the addition of ethanol and acetone can significantly improve the coating effect of fly ash, however, acetone is slightly toxic, more volatile, and expensive than ethanol, so ethanol is more suitable as a wetting agent to be added to the reaction system. Under the optimal coating conditions, when the ratio of ethanol and water is 1:1, the brightness of fly ash can reach 71.62 % ISO, which is 17.29 % ISO higher than that without ethanol.

Utilization of high-volume fly ash in pervious concrete mixtures for mangrove conservation

In environmental conservation, mangrove forests play a crucial role. Retransplanting mangrove propagules, however, faces challenges, and success rates are notably low. Achieving an optimal protector for propagules, balancing strength without impeding growth, is challenging. Mangrove propagules require a temporary protector with an optimal balance, neither too weak nor too strong, to shield them from current waves which is difficult. We propose using pervious concrete pots with high-volume fly ash activated with low NaOH concentrations. The investigation focuses on the influence of the mixing procedure on workability, compressive strength, and mineral composition. The novel discovery in this study is the specific sequence of stirring the ingredients using an alkali activator, which adds an interesting dimension to the research. It is recommended to adopt Sequence 2 in pervious concrete production, where NaOH dissolved FA in the mixture forming albite as N-A-S-H gel product. It surely enhanced both workability and the strength confirming uniform application processes. The two recommended variants, PFS-60 and PFBS-50, effectively utilize coal ash, meeting the target compressive strength range of 3–5 MPa and providing support for mangrove pots over a 3–4 year period. Notably, both compositions maintained consistent mechanical properties during exposure to tidal conditions for 240 days.They exhibit high permeability (694 liter/m²/minute), facilitating efficient water passage without sediment entrainment.