Recycling Of Fly Ash Research Articles

Influence of Vermicomposted Coal Fly Ash on Morphological and Cytological Attributes of Ricinus communis L.

In view of the environmental problems generated by the large-scale production of fly ash, increasing attention is now being paid to the recycling of fly ash as a good source of nutrients. To reduce the cost of fly ash disposal and best utilization, it aimed to convert the fly ash into valuable vermicompost. Stated throughout the experiment, we opted for a soil sample and fly ash and pressed with different concentrations (control, 20%, 50%, 80% and 100%). Subsequently, all the mixtures were vermicomposted for 60 days by adding 100 Earthworms (Eisenia foetida) in each pile. The X-ray fluorescence spectroscopy measured the composition of the metal in fly ash as well as the nutritional content in the soil. This is followed by examining the morphological characteristics and cytogenetic study of Ricinus communis L. The present study indicated that E. foetida mitigates the toxicity of fly ash and is hence used as valuable vermicompost.

Fabrication and performance analysis of sustainable municipal solid waste incineration fly ash alkali-activated acoustic barriers

Abstract The recycling of hazardous municipal solid waste incineration fly ash (MSWIFA) is drawing more attention, in which the alkali-activation technique may provide great potential to make full use of it as sustainable acoustic materials. The present work evaluated the applicability of alkali-activated MSWIFA-based materials (AAFMs) as porous acoustic barriers. The chemical composition and microtomography of the as-prepared AAFMs were characterized by X-ray diffraction. Fourier-transform infrared spectroscopy, and scanning electron microscopy. With the incorporation of MSWIFA and foaming agents, the dry bulk density and porosity of AAFMs were subsequently examined. Moreover, the compressibility and leachability of AAFMs were also investigated to evaluate their mechanical performance and environmental safety as construction materials. A sound absorption test was eventually conducted to explore the sound absorption performance of AAFMs, considering the main factors such as aluminum addition, MSWIFA dosage, and sample thickness. The results verified the good chemical stability, leachability, and sound absorption performance of porous AAFMs. Specifically, it indicated that the aforementioned factors have a boosting effect on forming highly porous structures that improve sound absorption performance, namely sound absorption coefficient and noise reduction coefficient.

Characterization and recycling of raw fly ash derived through stems of Sesamum indicum as a proficient adsorbent for chlorazol black E from wastewater

Coal fly ash (CFA) is an anthropogenic industrial byproduct that is expected to increase exponentially to fulfill the needs of energy using coal and agro-waste as a cheap fuel. The disposal of this classified human carcinogen is a major concern in developing and underdeveloped economies due to lack of resources. Recycling and value addition of industrial waste, coherence with sustainable development goals is a viable solution. Zeolitization of coal fly ash is an ideal approach for recycling this waste into superior products to be used in a variety of industrial applications. This study was aimed to recycle CFA to useful zeolites using ultrasound assisted hydrothermal process. Sesamum indicum plant stems based fly ash (rFA) was found to belong to class “F" and has very low moisture and carbon contents. To investigate the morphology and elemental composition of rFA and UHSZ, SEM/EDX was used along with XRD, FTIR and Raman spectroscopy which confirmed the existence of quartz, mullite and anhydrite. SEM/EDX results revealed the presence of Al, Si, S, K, Sb, Mg and Ta in raw ash. Adsorption studies of both rFA and synthesized zeolite(UHSZ) were conducted to determine the quintessential parameters of pH, time, initial dose of adsorbent for optimum results. Fabricated zeolites (2 ​g/100 ​mL) from raw fly ash removed 90–98% of chlorazol black E (DB38) from 100 ​mg/L solution within 40 ​min at pH ​≈ ​7. Both Langmuir and Freundlich isotherms gave best fit, which validated that the adsorption of DB38 to UHSZ was a blended process rather than a simple monolayer adsorption mechanism. Pseudo 1st-order and 2nd-order kinetic models were adopted to fit the obtained kinetic data. The pseudo 2nd-order kinetic model was found to be most related.

Life-Cycle Assessment of Municipal Solid Waste Incineration Fly Ash Recycling as a Feedstock for Brick Manufacturing

The recovery of municipal solid waste incineration (MSWI) fly ash is currently considered to be the most viable solution for its management. However, in developing resource recovery technologies, it is crucial to consider the overall environmental impact. This study employed a life-cycle assessment (LCA) to compare environmentally friendly red bricks partially utilizing MSWI fly ash as a raw material with conventional red bricks. The results demonstrate that the use of phosphoric acid during the resource recovery process imposes the most significant environmental burden, followed by electricity consumption. To address this issue, in this study, we simulated the replacement of phosphoric acid with phosphoric acid monohydrate recovered from discarded fire extinguishers, resulting in the production of second-generation environmentally friendly red bricks. The analysis revealed that the environmentally friendly red bricks exhibited a mere 5.52% increase in total environmental impact compared with traditional red bricks. Moreover, by stabilizing heavy metals using recovered phosphoric acid monohydrate, the second-generation environmentally friendly red bricks achieved an 8.75% reduction in total environmental impact relative to traditional red bricks. These findings highlight the environmental benefits of fly ash reuse in red brick production, and the incorporation of other industrial waste or byproducts could further enhance its efficacy. The application of the LCA facilitated the identification of key areas for improvement and enabled precise evaluation of the environmental benefits associated with waste reuse.

Heavy Metals from NEFA Recycling as a Road Base Material: Release Dynamics and Impacts on a Shallow Aquifer

The recycling of fly ash for structural fill uses, such as road base materials, is the most promising avenue to dissipate fly ash. Traditional risk assessment methods do not take into account the ultra-alkaline nature of new emerging fly ash (NEFA) and may underestimate the risk of long-term release of heavy metals and contamination of shallow diving when fly ash is utilized as a road base material. In this study, carbonation experiments are used to reveal the heavy metal release characteristics of NEFA under natural aging conditions and to assess the environmental risk and regional variability characteristics of pollutant release to shallow aquifers under the new fly ash road utilization scenario based on process modeling and Monte Carlo methods. The results showed that the heavy metal release concentrations in carbonized NEFA increased by a factor of 1.17–114.56 with natural aging. This would result in a dramatic increase in the shallow aquifer contamination risk when this material is used as a road base in typical areas. Exposure concentrations of four heavy metals, Ni, Cu, Zn, and As, increased by 1.27–113.89 times, and Cd concentrations increased from 0 mg/L to 0.055 mg/L. Ground infiltration differences due to regional differences in rainfall and other factors lead to differences in the shallow aquifer contamination risk in different areas. Heavy metal exposure concentrations can vary by up to 1.55 times. The results of the study confirm the significant long-term increase in heavy metal release and risk under NEFA resource utilization conditions and the shortcomings of traditional methods in characterizing their release and risk dynamics. In response, it is recommended that attention be paid to the long-term risk of NEFA resource utilization and that a methodological system for characterizing the heavy metal release potential and risk assessment of NEFA be developed.

Green Building Materials: Mechanical Performance and Environmental Sustainability

In recent years, in the field of waste management, waste-to-energy plants have been attained great attention as a valid method for mitigating landfill disposal in addition to valorizing waste from the energy point of view. Moreover, there are several technological proposals aimed at valorizing and reusing the residues produced by incinerators. Nonetheless, pre-treatment and treatment techniques, including washing and the solidification/stabilization process, may be necessary for the recovery and recycling of this type of by-product. In this regard, the objective of this research is the production of lightweight artificial aggregates with acceptable quality, capable of guaranteeing specific requirements and technical performance, through the recycling of fly ash derived from municipal solid waste incineration (MSWI). The properties of the three types of aggregates, produced through the cold-bonding pelletization, were evaluated through the mechanical and leaching tests.

Integrating Fly Ash-Controlled Surface Morphology and Candle Grease Coating: Access to Highly Hydrophobic Poly (L-lactic Acid) Composite for Anti-Icing Application

New ways of recycling fly ash are of great significance for reducing the environmental pollution. In this work, biodegradable hydrophobic poly (L-lactic acid)/fly ash composites for anti-icing application were successfully fabricated via a facile solvent-volatilization-induced phase separation approach. A silane coupling agent of 3-(Trimethoxysilyl) propyl methacrylate was used to decorate a fly ash surface (FA@KH570) for strengthening the interface bonding between fly ash and poly (L-lactic acid). Moreover, FA@KH570 could obviously enhance the crystallinity of poly (L-lactic acid) (PLLA)/FA@KH570 composites, which accelerated the conversion from the liquid-liquid to the liquid-solid phase separation principle. Correspondingly, the controllable surface morphology from smooth to petal-like microspheres was attained simply by adjusting the FA@KH570 content. After coating nontoxic candle grease, the apparent contact angle of 5 wt% PLLA/FA@KH570 composite was significantly increased to an astonishing 151.2°, which endowed the composite with excellent anti-icing property. This strategy paves the way for recycling waste fly ash and manufacturing hydrophobic poly (L-lactic acid) composite for potential application as an anti-icing material for refrigerator interior walls.

Facile treatment of municipal solid waste incineration fly ash by one-step microwave hydrothermal method: Hazards detoxification and tobermorite synthesis

A one-step microwave hydrothermal method is proposed here for the harmless treatment and resource recycling of water-washed municipal solid waste incineration fly ash (WMSWI-FA). Dioxins and heavy metals in WMSWI-FA can be detoxified, tobermorite can be synthesized by adjusting the parameters of NaOH dosage, reaction temperature and time. We conclude that NaOH is essential to synthesize tobermorite from WMSWI-FA, and higher temperatures and longer times are beneficial for degrading dioxins. However, excessive NaOH has a negative effect on the degradation of dioxins. Experiments showed that adding 20 wt% NaOH to WMSWI-FA and reacting at 260 °C for 3 h, the tobermorite was successfully synthesized, the residual dioxins (42.80 ng-TEQ/kg) and the leaching concentrations of heavy metals were lower than the limited value of the HJ 1134–2020 standard. The hydrothermal treated WMSWI-FA contains tobermorite, which supports it to be recycled as construction material and adsorbent. The one-step microwave hydrothermal treatment demonstrates favorable industrialization prospects, as it performs well in harmless treatment and resource utilization of WMSWI-FA.

Enhancement of early-age properties of high-volume fly ash–cement paste with hydrated lime powder

Recycling and reusing of high-volume fly ash (HVFA) in the development of construction materials have received much attention from research scholars worldwide. However, the early-age properties of the materials with HVFA are not as good as the conventional cement-based materials. Therefore, the effect of hydrated lime powder (LP) addition on the enhancement of early-age properties of HVFA-cement pastes was investigated in the present study. Various paste mixtures were prepared by adding different LP amounts (5, 10, 15, 20, and 25% by mass) to the HVFA paste containing 30% Portland cement (PC) and 70% fly ash (FA). All of the HVFA paste mixtures were prepared with constant FA/powder (including PC and FA) and water/powder ratios (by mass) of 0.7 and 0.3, respectively. The setting time (ST) and workability of the fresh mixtures were first measured then the tests of compressive strength (CS), water absorption (WA), and drying shrinkage (DS) were performed on the hardened samples of up to 28 days to study the influence of LP addition on the early-age properties of the samples. It is found that adding LP greatly affected the early-age properties of the HVFA-cement pastes in both fresh and hardened stages. In detail, adding LP reduced the flowability and significantly shortened the ST of the HVFA paste mixtures. In addition, the CS values of the 28-day-old HVFA paste samples incorporating 5–15% LP were increased by 20.1–34.4% in comparison to that of the reference sample without LP addition. However, the strength values were found to be decreased remarkably when adding 20 and 25% LP to the paste mixtures. Similarly, the inclusion of 5–15% LP improved the WA and DS behavior of the hardened paste samples. As a result, a 15% LP addition was recognized as the optimum content for enhancing the short-term properties of the HVFA-cement pastes.

Firing-Associated Recycling of Coal-Fired Power Plant Fly Ash.

Coal-fired power plant fly ash is a global environmental concern due to its small particle size, heavy metal content, and increased emissions. Although widely used in concrete, geopolymer, and fly ash brick production, a large amount of fly ash remains in storage sites or is used in landfills due to inadequate raw material quality, resulting in a waste of a recoverable resource. Therefore, the ongoing need is to develop new methods for recycling fly ash. The present review differentiates the physiochemical properties of fly ash from two coal combustion processes: fluidized bed combustion and pulverized coal combustion. It then discusses applications that can consume fly ash without strict chemical requirements, focusing on firing-associated methods. Finally, the challenges and opportunities of fly ash recycling are discussed.

Experimental Study on Liquefaction Characteristics of Saturated Sands Mixed with Fly Ash and Tire Crumb Rubber

The liquefaction of saturated sandy soils during dynamic loading can inflict excessive damage on the structures, leading to significant human and economic losses. Recycling and reusing industrial waste materials may offer a sustainable and economic solution to this problem. This study investigates the influence of two waste materials, namely, recycled fly ash and tire crumb rubber, on the liquefaction characteristics of sand. For this purpose, loose and medium-dense triaxial specimens were prepared using sand–fly ash mixtures containing 0–40% of fly ash and sand–tire crumb rubber mixtures containing 0–30% of crumb rubber. The liquefaction characteristics of the specimens were examined through a series of stress-controlled, undrained, dynamic triaxial tests. The tests were conducted at 1 Hz loading frequency and under initial effective confining stresses of 50 and 100 kPa. The experimental results showed that, at a similar relative density, the liquefaction resistance of the sand–fly ash specimens decreased as the fly ash content (FA) increased up to about 20%; then, it slightly increased until FA reached 40%. Sand-only specimens showed greater liquefaction resistance than sand–fly ash specimens. The liquefaction resistance of the sand–tire crumb rubber specimens was enhanced by increasing the rubber content (RC) in the mixtures. It was found that the increasing liquefaction resistance of sand with the addition of tire crumb rubber was more noticeable under higher confining stresses.

Recycling of Coal Fly Ash in Building Materials: A Review

Coal fly ash (CFA) is a type of solid waste produced in the process of coal combustion, which is rich in silicon oxide, aluminum oxide and a small number of heavy metals and radioactive elements. Therefore, CFA is considered a secondary resource with high recovery value. Currently, CFA is mainly reused in the fields of building materials, mine backfilling, soil conditioners and fertilizers, among which the production of building materials is one of the most important ways to realize large-scale utilization of CFA. This paper introduces the physical and chemical properties, classification and environmental impact of CFA and summarizes the utilization status of CFA in building materials such as cement, concrete, ceramics and geopolymers, as well as the management policy of CFA. In addition, the existing problems in the utilization of CFA as a building material are analyzed, and their development prospects are discussed.

Production of water-permeable ceramic bricks derived from fly ash via a simple pellet method: Mechanism of mechanical strength and permeability

• Water-permeable ceramic bricks were prepared from fly ash via a simple pellet method. • The consumption of fly ash in the ceramic brick was up to 80 wt%. • Average pore size of water-permeable ceramic bricks reached 123.9 μm. • Anorthite phases generated at high temperature contributed to strength of bricks. • The water-permeable ceramic bricks had a low heavy metal leaching toxicity. Rising with the sponge city construction, water-permeable bricks as emerging materials, are receiving more and more attentions. It is a beneficial way to produce water-permeable bricks using industrial solid wastes as raw materials, which could not only eliminate the adverse effect of solid wastes, but also produce sustainable products. Herein, water-permeable ceramic bricks were produced by recycling fly ash as the main material with consumption up to 80 wt% via a simple pellet method. Fly ash was firstly mixed evenly with tailings at a mass ratio of 4:1 to adjust plasticity to prepare pellets. Pellets were then pressed under low forming pressure to obtain raw bricks, which were dried and sintered at high temperature to prepare water-permeable ceramic bricks. Effects of size and water content of pellets, forming pressure, and sintering temperature on the performance of water-permeable ceramic bricks were investigated. Under optimized conditions, ceramic bricks with compressive strength of 48.6 MPa, bending strength of 6.1 MPa and water permeability of 2.83 × 10 -2 cm/s were produced. Average pore size of optimized bricks reached 123.9 μm, which guaranteed excellent water permeability. The generated anorthite phases at high temperature contributed to the high mechanical strength of water-permeable bricks. The evaluation of heavy metal leaching toxicity indicated that the prepared bricks were environmentally-friendly. This study provides a strategy to produce water-permeable ceramic bricks derived from industrial solid wastes.

Recycling of municipal sewage sludge incineration fly ash based on (NH4) 2SO4 roasting-acid leaching and filling PP matrix process.

Sludge incineration is one of the most efficient sludge treatment methods. The fly ash produced by incineration must be handled further since it has a significant number of heavy metals. In this study, the chemical composition of sewage sludge incineration fly ash (SSA) generated from Zhejiang in various months was identified by XRD, X-ray fluorescence spectrometer (XRF), and SEM analyzes. The SSA were treated by a (NH4)2SO4 roasting-acid leaching process to determine its effect on the elimination performance of heavy metals. The SSA content on the mechanical properties and heavy metal leaching of modified SSA-filled PP composite were also studied. Results show (NH4)2SO4 roasting-acid leaching process has a good effect of eliminating heavy metals, with the highest leaching of Zn of 86.4%. The presence of sodium stearate modifier increases activation index of SSA and then improves the compatibility of SSA particles in PP, resulting for the composites have relatively excellent mechanical properties. For the toxicity characteristic leaching procedure (TCLP) test, modified SSA particles can be effectively encapsulated with PP resins, which have a considerable inhibitory effect on heavy metal leaching. This process from this study provides a reference for sewage sludge treatment by using modified SSA as a polymer filler to achieve the immobilization of heavy metals and the resource recycling.

Preparation of non-sintered sewage sludge based ceramsite by alkali-thermal activation and hydration mechanism

The recycling of sewage sludge (SS) and fly ash (FA) is significant for the disposal of increasing solid waste. In this study, SS and FA were used as raw materials, and sodium hydroxide (NaOH) and calcium oxide (CaO) were used as alkali activators to prepare non-sintered ceramsite under room temperature curing, and the optimal preparation conditions for the ceramsite were determined through single-factor experiments. Alkaline-thermal activation (ATA) was used to enhance the activity of SS and FA, and the results showed that the activities of SS and FA after ATA were largely improved, and composite activation by CaO and NaOH is more effective than that by either CaO or NaOH. The formed abundant sodium silicate hydrate (N-A-S-H) gels and few hydrated calcium silicate (C-A-S-H)/hydrated silicate (C–S–H) gels can bind well with the particles inside the ceramsite to form the denser structure. In addition, the cylindrical compressive strength of the ceramsite can reach 7.43 MPa, while the apparent density, bulk density, and water absorption are 2603 kg/m3, 852 kg/m3, and 8.37%, respectively under the conditions that the ratio of SS to FA is 8: 2, 9 wt% NaOH and 6 wt% CaO and 600 °C thermal activation, which can meet the standard of ceramsite (GB/T 17431.1–2010). This study provides an effective way for the utilization of SS and FA.

Green-Engineered Cementitious Composite Production with High-Strength Synthetic Fiber and Aggregate Replacement

Engineered cementitious composites (ECCs) are potentially useful structural reinforcement and repair materials. However, owing to their high costs and carbon emissions, they are not used extensively. To control these carbon emissions and costs, recycled fly ash cenospheres (FACs) and high-strength polyethylene (PE) fibers are used here to explore the possibility of developing green lightweight ECCs (GLECCs). A series of experiments was conducted to test the physical and mechanical properties of the developed GLECC and to evaluate the possibility of developing an GLECC. The crack width development of the GLECC was also analyzed using the digital image correlation method. The experimental results indicate the following: (1) The increase in FAC content and the decrease in PE content worsened the performance of GLECCs, but the resulting GLECCs still had significant strain-hardening properties; (2) The performance and costs of GLECCs can be balanced by adjusting the amount of FAC and PE. The maximum amount of FACs attainable is 0.45 (FAC/binder), and the required amount of PE fibers can be reduced to 1%. As a result, the cost was reduced by 40% and the carbon emission was reduced by 36%, while the compressive strength was greater than 30 MPa, the tensile strength was greater than 3.5 MPa, and the tensile strain was nearly 3%. (3) The width of the crack was positively correlated with the FAC content and negatively correlated with the fiber content. In the 0.8% strain range, the average crack width can be controlled to within 100 μm and the maximum crack width can be controlled to within 150 μm, with the performance still meeting the requirements of many applications.

Waste recycling of coal fly ash: A novel approach to prepare hierarchically porous coal fly ash/Al2O3 ceramic composite with high porosity and high strength templated by emulsion-assisted self-assembly

The coal fly ash (CFA) produced from coal-fired power generation is classified as a common solid waste; thus, improving the recovery and utilization rate of CFA is highly desirable. In this study, a novel strategy using CFA and Al2O3 as raw materials, to prepare hierarchically porous ceramic composites that serve as potential candidates for future building materials is developed. In this process, the well-developed self-assembly method in which an anionic modifier is used to prepare hydrophobic powders that form an attractive oil/water network via electrostatic interactions, thereby yielding honeycomb-like structures. In order to explore the mechanism of preparation, five samples with different mixture ratios of alumina and CFA were prepared according to 1: 0, 2: 1, 1: 1, 1: 2, and 0: 1 (Alumina: CFA). Compared with the sample prepared with pure CFA, the as-prepared CFA/Al2O3 composite exhibited both superior porosity and high mechanical property. When the porosity is as high as 73 ± 0.17%, the compressive strength is as high as 80.9 ± 3.4mpa (alumina: CFA = 1:1). As the porosity decreases to 49.3 ± 0.7%, the compressive strength reaches 159.33 ± 36.89mpa (alumina: CFA = 1:2). Moreover, this work obtains the highest compressive strength-porosity related B-value in comparison to previously reported CFA-based composites and provides a new insight into the effective recycling of CFA and offers a novel approach to prepare CFA/Al2O3 composite with excellent overall mechanical properties.

Rapid identification of reactivity for the efficient recycling of coal fly ash: Hybrid machine learning modeling and interpretation

As the main solid waste produced by coal combustion, the large accumulation of coal fly ash (CFA) causes serious environmental pollution and resource waste. Whether CFA can be recycled depends on its reactivity, which in turns can be represented by its amorphous content. This paper established random forest regression models optimized by artificial bee colony (ABC) for rapid screening of CFA, based on the correlation between chemical composition and amorphous phase. The study evaluated the model using correlation coefficient, r-square, root mean square error, and mean absolute error, giving results of testing set of 0.773, 0.477, 6.542, and 5.279. Feature importance and permutation importance were used to measure feature contribution. Partial dependence plots, Shapley additive explanations, and local interpretable model-agnostic explanations were also used to give global and local interpretation of the model performance. The overall results showed that Al2O3, MgO and CaO had the greatest influence on the amorphous content within CFA. When the mass fractions of Al2O3, MgO and CaO varied from 17.5% to 22.5%, 2%–4% and 10–15%, the mass fraction of amorphous phase reached the highest. For different CFA samples, chemical composition played a different role in determining the amorphous content. The post-analysis of the model provided some reference for promoting CFA recycling. The above results proved that the established model had good robustness and generalization capability, which can effectively determine the potential of CFA as supplementary cementitious materials to promote the cleaner production of cement or geopolymer resources.

The Recycling of Coal Fly Ash: A Review on Sustainable Developments and Economic Considerations

The recycling and utilization opportunities for coal fly ash (CFA) have increased in the past two decades. However, limited commercialization of the material is still reported, while disposal and management remain major concerns. CFA utilization is currently commercially feasible in the building and construction industry. Other alternative uses that are being explored involve the extraction of valuable metals and the purification of wastewater. The CFA-produced adsorbent material utilized in wastewater purification processes should be able to generate water that meets the legal quality requirements for reutilization in alternative applications. On the other hand, in the recovery of metallic components such as smelter-grade alumina, high recovery and high purity products are only achievable through the processing of CFA using expensive and energy—intensive processes. Furthermore, most of the current CFA recycling processes tend to generate secondary solid residues (SSR), which can cause environmental pollution, thus requiring further downstream processing. In this context, this paper reviews and discusses current research on CFA recycling methods, challenges and opportunities associated with resource recovery from CFA, and the acceptability of the value-added products, and it therefore proposes sustainable processes for CFA utilization. This review further suggests that to successfully compete with bauxite for production of smelter-grade alumina, other saleable value-added products such as Ti, Fe and the REEs should be recovered by engineering an integrated process design. The generated SSR in each process must also be characterized, recycled and re-used to reduce waste production and advance the circular economy concept. The review concludes that for CFA to become considered as a more attractive commercial resource, there is need for its complete and holistic utilization in high volumes and in different applications to offset its low value.

Rational design of fly ash-based composites for sustainable lithium-ion battery anodes

Lithium-ion batteries (LIBs) have dominated the energy market for decades, but the sustainability considerations should be included when designing future electrode materials due to the complex preparation process and severe volume expansion of the current Si-based anode materials. As an atmospheric pollutant, Fly ash (FA) is worth considering as a potential source of silicon, whereas the conventional magnesiothermic reaction to extract silicon from FA for LIBs is complex, costly and energy consuming. Herein, FA is employed directly as “green” and advanced anode of LIBs after being anchored on the carbon micro-sheets (FA/C) via low cost and solvent-free approach. Owing to the remarkably enhanced electric conductivity and mechanical properties, the resulting battery delivers an excellent capacity of 688 mAh g−1 at 0.1 A g−1, ultrahigh capacity retention of 97.9% over 6000 cycles and effectively mitigated volume variation, outperforming many Si-based anodes reported. Remarkably, the full battery with LiFePO4 cathode displays ideal rate capability and long-term durability, demonstrative of great potential in practical application. Moreover, this low cost, free of organic solvents, harsh acids and surfactants method can be extended to FA/graphite and FA/MXene composites, thus providing an insight for sustainable recycling of fly ash and construction of durable LIBs.