Recycling Of Fly Ash Research Articles

Recycling Fly Ash into Lightweight Aggregate: Life Cycle Assessment and Economic Evaluation of Waste Disposal

This study analyzed environmental impacts and economic feasibility to evaluate whether recycling fly ash, which has rarely been addressed in previous studies, as a raw material for lightweight aggregates can be a sustainable waste management alternative. This study presents a comparative analysis of three disposal scenarios: landfill disposal, recycling as cement raw material, and recycling as lightweight aggregate raw material. Nine environmental impacts were assessed through life cycle assessment (LCA): acidification, global warming, eutrophication, photochemical oxidation, stratospheric ozone depletion, human toxicity, freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, and terrestrial ecotoxicity. The results showed that the landfill disposal scenario posed the greatest threat to global warming, eutrophication, and marine aquatic ecotoxicity, while the cement scenario had the greatest impact on stratospheric ozone depletion, human toxicity, and other ecotoxicity items while recycling as lightweight aggregate showed the lowest environmental impacts in most items except acidification and photochemical oxidation. Life cycle costing (LCC) analysis was also performed to compare the economic aspects of each scenario. The lightweight aggregate scenario is more energy-intensive and costly, but it has significant economic benefits due to the significant revenues from the products produced. Therefore, even though the cost is high, this scenario is considered economically advantageous. This study highlights that recycling fly ash into lightweight aggregate reduces environmental impacts, provides economic benefits, and is a better alternative to landfilling and recycling cement raw materials. It will also contribute to promoting sustainable practices of fly ash recycling.

Synergistic recycling of MSWI fly ash and incinerated sewage sludge ash into low-carbon binders

This study proposed a novel method for synergetic recycling of municipal solid waste incineration fly ash (IFA) and incinerated sewage sludge ash (ISSA) to produce low-carbon binders. The hydration mechanism, physical properties, and environmental risks associated with the designed binders were thoroughly evaluated. The results revealed a compositional complementary effect between IFA and ISSA, with ettringite being identified as the main crystal product resulting from the reaction between Ca2+ and SO42- in IFA and reactive aluminates in ISSA. The chlorides in raw IFA were effectively immobilized by the formation of various Cl-containing products, and all potentially toxic elements were immobilized in the binder system, exhibiting low leachability. Besides, CaO was found to be a highly efficient activator, providing additional reactive Ca2+ for the formation of more abundant and larger ettringite crystals, which consequently led to the high compressive strength (> 40 MPa) of the designed binders. Overall, this study provided a feasible approach for the upcycling of IFA and ISSA, contributing to the realization of “Zero-waste city” and the advancement of sustainable construction materials.

Integrated Use of Furnace Bottom Ash as Fine Aggregate and Cement Replacement for Sustainable Mortar Production.

Recycling fly ash (FA) and furnace bottom ash (FBA) help with reducing greenhouse gas emissions, conserving natural resources, and minimizing waste accumulation. However, research on recycling FBA is progressing more slowly compared to FA. This research aims to investigate the combined use of FBA as a replacement for both fine aggregate and cement and its influence on the performance of mortar. The findings indicated that incorporating 25% FBA as a fine aggregate replacement and 10% or 20% ground FBA (GFBA) as a cement replacement significantly enhanced compressive strength after 28 and 56 days. Flexural strength was comparable to control mortar at 28 days and superior at 56 days. However, increasing the FBA content beyond 25% as a fine aggregate replacement reduced workability and increased porosity, which negatively affected mechanical performance and water absorption. Microstructural analyses revealed denser and more compact structures in the mortar with combined FBA replacement for both fine aggregate and cement, specifically 25% as a fine aggregate replacement and 10% and 20% as cement replacements. Optimal performance was noted in mixtures with Ca/Si and Ca/Al ratios within the ranges of 1.8-1.5 and 0.24-0.19, respectively. Trace element leaching analysis has not shown significant differences between GFBA, FA, and OPC. Regarding environmental impact assessment, using FBA as a fine aggregate replacement did not show a significant reduction in CO2 emissions, but replacing cement with FBA reduced emissions remarkably. Generally, using FBA as a replacement for both fine aggregate and cement in mortar enhances compressive and flexural strengths at optimal levels, promotes sustainability by reducing landfill waste and CO2 emissions, and supports cleaner production practices despite some workability challenges.

Mechanical and durability properties of polymer fiber reinforced one-part foam geopolymer concrete: A sustainable strategy for the recycling of waste steel slag aggregate and fly ash

This paper assesses the feasibility of geopolymers (GPs) for use as lightweight foamed concrete, a crucial step towards reducing the carbon footprint and conserving natural resources. A powder activator (i.e., sodium metasilicate) less harmful to the environment was used to activate the fly ash-based GPs, while the limestone aggregates were gradually replaced by up to 100 % waste slag materials to conserve natural resources. Polypropylene fibers were incorporated at high dosage rates of 1 % or 2 %, by volume, to reduce the concrete density and improve its durability properties. Tested properties include flow, density, water absorption, porosity, thermal conductivity, mechanical strengths, drying shrinkage, and resistance to sulfate attack, freeze/thaw cycles, and elevated temperature. Results showed that the concrete mechanical properties improved when the limestone aggregate was replaced by slag materials, but the density and thermal conductivity were slightly curtailed at higher addition rates. The use of polypropylene fibers proved efficient to improve the resistance to freeze/thaw cycles, drying shrinkage, and expansion due to sulphate attack. Such data can help sustain the green building industry development by reducing the carbon footprint and conserving natural resources in foamed concrete applications.

Effect of Fly Ash and Metakaolin Substituted Forms on Structural Properties in Light Mortar with Pumice Aggregate

In this study, experimental tests were conducted on composite mortars in different forms prepared using lime, pumice, fly ash, and metakaolin. This research aims to recycle fly ash produced as industrial waste and produce a building material that is durable, lightweight, and provides good insulation. In the composite structure mortar mixture designs prepared for the experiments, CEN standard sand was replaced with Nevşehir pumice (0.5-4 mm) at the rates of 10%, 20%, and 30%, respectively, and fly ash-metakaolin was replaced with the cement at the rates of 10%, 20%, and 30%, respectively. A total of 13 different mixtures were prepared. Unit volume mass test, Ultrasonic test, water absorption test, compressive strength test, bending test, thermal conductivity coefficient test, scanning electron microscope (SEM) analysis, and thermogravimetric - differential thermal (TGA/DTA) analysis were performed on the prepared samples. ) analyses were made. As a result of the research, it was determined that T30 (All: Pumice + Fly Ash + Metakaolin) mortar mixture provided the highest compressive strength and thermal conductivity coefficient and the lowest dry unit volume weight compared to other mortar mixtures.

Applicability assessment of a plasma melting technology for a fly ash recycling system in the Republic of Korea

ABSTRACT The Ministry of Environment of Korea has proposed a ban on landfill disposal of municipal solid waste (MSW) from 2026. Thus, it is inferred that the amount of incineration ash will increase drastically. Against this backdrop, this study assessed the applicability of a plasma melting process to fly ash. Fly ash was collected from 14 incineration facilities to analyze its basic properties and perform melting experiments. Furthermore, scanning electron microscope (SEM) analysis and economic feasibility assessment were conducted. The molten fly ash slag exhibited a pH value of 9.9, and the ignition loss of fly ash was found to range from 14.5 to 25.7 wt.%. None of seven toxic elements (arsenic (As), cadmium (Cd), cyanide (CN), mercury (Hg), hexavalent chromium (Cr(VI)), copper, and lead (Pb)) was detected from the molten slag. In addition, 99.3 wt.% of chloride ion (Cl−), 97.9 wt.% of fluoride ion (F−), and 98.1 wt.% of sulphate ion (SO4 2−) were removed. The contents in the molten slag were found to be 0.19, 7.8, 27.8, 33.1, and 38 mg/kg for Cd, Pb, zinc, nickel, and F, respectively, and none of CN, Hg, and As was detected, thereby meeting the criteria for soil pollution. All of the environmental standards were met, and SEM analysis confirmed stable quality with high density and no surface pore. In the economic feasibility assessment, a profit of approximately 152.4 $/ton was also estimated compared to landfill disposal.

Carbon Dioxide Capture under Low-Pressure Low-Temperature Conditions Using Shaped Recycled Fly Ash Particles

Carbon-capture technologies are extremely abundant, yet they have not been applied extensively worldwide due to their high cost and technological complexities. This research studies the ability of polymerized fly ash to capture carbon dioxide (CO2) under low-pressure and low-temperature conditions via physical adsorption. The research also studies the ability to desorb CO2 due to the high demand for CO2 in different industries. The adsorption–desorption hysteresis was measured using infrared-sensor detection apparatus. The impact of the CO2 injection rate for adsorption, helium injection rate for desorption, temperature, and fly ash contact surface area on the adsorption–desorption hysteresis was investigated. The results showed that change in the CO2 injection rate had little impact on the variation in the adsorption capacity; for all CO2 rate experiments, the adsorption reached more than 90% of the total available adsorption sites. Increasing the temperature caused the polymerized fly ash to expand, thus increasing the available adsorption sites, thus increasing the overall adsorption volume. At low helium rates, desorption was extremely lengthy which resulted in a delayed hysteresis response. This is not favorable since it has a negative impact on the adsorption–desorption cyclic rate. Based on the results, the polymerized fly ash proved to have a high CO2 capture capability and thus can be applied for carbon-capture applications.

Recycling of fly ash to synthesize zeolites for efficient removal of dioxins

The large amount of fly ash (FA) produced by coal-fired power plants places tremendous pressure on the environment. Meanwhile, toxic dioxins emitted from municipal solid waste incineration plants are of great concern. To address these challenges, a win-win approach was proposed to re-utilize FA for synthesis of zeolite materials for dioxins adsorption. The results indicate that the Si/Al molar ratio in the liquid-phase precursor significantly influences the distribution of Si-Al 4-membered rings (Si/Al=1) and Si-Al 4-membered rings (Si/Al=3) in the system. These units are key secondary structures of the zeolite skeleton, determining the proportions of A-type and X-type zeolites in the product. With the increasing Si/Al molar ratio of precursor, the specific surface area and Si/Al molar ratio of zeolites derived from fly ash (ZFA) both increased, while they played a positive and negative role in dioxins adsorption, respectively. The adsorption of dioxins by ZFA peaked at a Si/Al molar ratio of precursor of 1.5, reaching 4.13×105 pg I-TEF/g, surpassing activated carbon by 1.46 times. This study not only elucidates the mechanism of Si/Al molar ratio of precursor on crystalline transformation of ZFA, but also confirms the potential of ZFA in dioxins adsorption.

Study of a Fire-Resistant Plate Containing Fly Ashes Generated from Municipal Waste Incinerator: Fire and Mechanical Characteristics and Environmental Life Cycle Assessment.

The recycling of fly ash from municipal solid waste incineration is currently a global issue. This work intends to examine the viability of a novel recycling alternative for fly ashes as a component of fire-resistant plates. To lessen the quantity of heavy metal leaching, the fly ash was utilized after being washed using a water/fly ash ratio of 2 for one hour. Subsequently, an inexpensive, straightforward molding and curing process was used to create a plate, with a composition of 60%wt of MSWI-FA, 30%wt of gypsum, 0.5%wt of glass fiber and 9.5%wt of vermiculite. The plate exhibited high fire resistance. Furthermore, it demonstrated compression, flexural strength and surface hardness slightly lower than the requirements of European Standards. This allows for manufacturing plates with a high washed MSWI-FA content as fire protection in firewalls and doors for homes and commercial buildings. A Life Cycle Assessment was carried out. The case study shows that a 60% substitution of gypsum resulted in an environmental impact reduction of 8-48% for all impact categories examined, except four categories impacts (marine eutrophication, human toxicity (cancer), human non-carcinogenic toxicity and water depletion, where it increased between 2 and 718 times), due to the previous washing of MSWI-FA. When these fly ashes are used as a raw material in fire-resistant materials, they may be recycled and offer environmental advantages over more conventional materials like gypsum.

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

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

Circular production of recycled binder from fly ash-based geopolymer concrete

This paper presents an investigation into the potential of recycling fly ash - based geopolymer concrete, to produce a recycled binder for circular re – use as starting material. The aforementioned would be a significant advantage over Portland cement which is non – recyclable, owing to its irreversible hydration. The experiment conducted involved crushing and sieving old parent fly ash – based geopolymer concrete, to separate out the paste from aggregate. The paste was then pulverized using a ball – mill to produce the recycled aluminosilicate starting material, herein referred to as recycled geopolymer cement (RGPC). Fly ash was blended with 0 to 100% RGPC, then used to prepare fresh geopolymer paste and mortar mixtures activated using a binary alkali activator consisting of sodium hydroxide and sodium silicate. Samples were cast then cured at 23 or 80 °C. The various tests done were workability, setting time, compressive strength, splitting tensile strength, drying shrinkage, water absorption, and volume of permeable pores. Analytical studies were done using X – ray diffraction, scanning electron microscopy and Fourier – transform infrared spectroscopy. Results showed that incorporation of RGPC into geopolymer mixtures generally led to reduction of workability and setting time, reduction of compressive and tensile strength, along with increase in drying shrinkage. It was, however, found that up to 60% RGPC can be incorporated into geopolymer mixtures while maintaining adequate performance suitable for structural applications. Unlike Portland cement, hardened geopolymer concrete is evidently recyclable to produce a circularly re – usable binder.

Facile Route for Effective Separation and Full-Scale Recycling of Fly Ash and Unburned Carbon.

The synchronous production of high-quality unburned carbon concentrate and cleaned ash from high LOI (loss on ignition) fly ash without yielding secondary solid waste is a dilemma issue. In this study, a viable flotation process with one rougher and two cleaners is developed for simultaneously obtaining carbon concentrate with a yield of 18.00% and an ash content of 17.49% and cleaned ash with a yield of 82.00% and a LOI of 4.63% from fly ash, reaching 84.72% of combustible substance recovery and 80.66% of flotation perfection index. The characteristic analyses of the stage by stage releasing products using laser particle size analysis, XRF, XRD, and SEM-EDS demonstrate that the inevitable factors that lead to a remaining higher ash content in the one-step flotation carbon concentrate are the random entrainment of mineral particles in the size range of 0-20 μm, especially the quasi-colloidal parts within 0-12.5 μm and the weak selective collection of fine-grained conjoined granules in the size range of 0-40 μm. Consequently, at least two cleaning steps are required for the effective separation of unburned carbon and ash. Furthermore, batch flotation test results show that diesel is superior to kerosene in the collection of unburned carbon, with an optimum dosage of 800 g/t; no. 2 oil acts more positively than MIBC for the separation of unburned carbon and ash, with an optimal dosing amount of 600 g/t; the optimum pulp concentration and flotation time are as follows: 100 g/L and 3.5 min for the rougher, 45 g/L and 2 min for the first cleaning, and 30 g/L and 3 min for the second cleaning. This study provides an economically feasible technological solution for the full-scale recovery of high-LOI fly ash in one step and avoids the problem of secondary solid waste that would have been generated in previous studies.

Recycling of Flyash: Route toward high-performance, eco-friendly, and cost-effective flexible strain sensor via synergizing multi-walled carbon nanotubes

Along with the widespread utilization of wearable and portable electronics, the rise of sensitive flexible strain sensors with wide detection range, excellent stability and affordable costs emerges as a substantial crux of this domain. Herein, we present a convenient and scalable approach for constructing high-performance flexible piezoresistive strain sensor by rationally assembling Flyash/Multi-carbon nanotubes (MWCNTs) active sensing hybrids. Owing to the unique heterostructure of Flyash/MWCNTs wherein Flyash is anchored with MWCNTs via polydopamine, the active sensing hybrids accommodated by porous polyurethane enables a sophisticated conductive network and large tensile deformability, permitting outstanding gauge factor of 1379, wide strain detection range of 0–100 %, remarkable operation stability and durability. Furthermore, the feasibility of sensor in human motions monitoring is validated. For the first time, the synergy of Flyash and MWCNTs demonstrates effective in advancing the sensing performance of piezoresistive strain sensor, providing a new sight towards high-performance, eco-friendly, and cost-effective flexible strain sensor.

Fixation of Coal Fly Ash (CFA) in the Form of Construction Blocks with Variable Combinations of Lime and FGD Gypsum

Coal fly ash (CFA) is produced on very large scales in thermal energy plants. The recycling of coal fly ash (CFA) is essential decreasing its environmental impact. In this research, a FaL-G (coal fly ash (CFA), lime, and FGD gypsum) technology is used to reuse coal fly ash (CFA) in brick-type form. First, all of the small-grained FaL-G were dried in the oven at 60and#176;C for 24 h. Three different combinations of coal fly ash (CFA), FGD gypsum, and lime were tested for block preparation. The blocks were treated with five conditions for hardening and drying, i.e., i. Sunlight, ii. Shade (room temperature), iii. Oven, iv. Presence of moisture, and v. Freezer (-16and#176;C). After complete drying, the compressive strength and flexural strength tests were applied. Over all, the sunlight treated blocks showed strong compressive strength of 5.9 MPa and flexural strength of 7.19 MPa. The blocks made through FaL-G technology are very good raw materials for construction, i.e., partition walls and decoration, as these blocks have impressive texture and plain edges. It was the first time that the variable combinations of coal fly ash (CFA), gypsum, and lime were tested through different conditions and have achieved good strength. The literature showed that little work has been carried out through FaL-G, while additional materials have also been used. The main novelty of the current research work is development of an enhanced technique for preparing building materials, stabilizing coal fly ash (CFA), and reducing its environmental hazards

Electrical Discharge Coating of Mild Steel with Fly Ash Suspension

Mild steel is a soft substance that rusts easily. It is easy to wear and corrode when exposed to harsh circumstances, such as in manufacturing sector. As a result, the mild steel surface must be modified to boost its durability and wearability. There are various techniques for coating mild steel and one of them is electrical discharge coating (EDC). In this study, the surface of mild steel was modified using EDC with fly ash suspension. Prior to the experiment, the element content, particle size, and surface morphology of fly ash were investigated. The EDC process was carried out using a Sodick AQ35L die-sinker EDM machine. The effects of varied amounts of fly ash on the features of the coated surface were also investigated. The experimental results revealed that raising the fly ash content increases the micro-hardness of the coated surface. Furthermore, utilising 20 g/l of fly ash powder resulted in the best coated surface finish with the least surface roughness. The concentration of fly ash has a significant impact on the thickness of the coating layer. These findings substantiate the viability of recycling fly ash as an environmentally sustainable coating material for modifying mild steel surfaces through the EDC method.

Effects of glass fiber on recycled fly ash and basalt powder based geopolymer concrete

This experimental study encompasses a comprehensive exploration of multiple parameters aiming to enhance the strength, workability, setting time, and environmental attributes of geopolymer concrete (GPC). A pivotal solution lies in substituting fly ash with waste basalt powder, not only reducing binder costs but also ameliorating the overall ecological footprint. A secondary significant factor entails the integration of trimmed glass fibers. Throughout the experimentation process, the predominant GPC binder and fly ash underwent substitution with basalt powder at the proportions of 25%, 50%, and 75%. The mixtures were augmented with glass fibers of 3 mm, 6 mm, and 12 mm lengths, introduced at the ratios of 0.5%, 1%, 2%, and 3%. Then, the acquired samples were subjected to a 24-h curing regimen in an 85 °C oven. Subsequently, after a 7-day period of exposure to external conditions post-incubation, these samples were tested for both the compressive and flexural strengths. Samples incorporating a basalt powder ratio of 50% exhibited the highest capacities, contrasting with reduced capacities when the basalt powder ratio was elevated to 75%. Conversely, samples utilizing a sodium hydroxide (NaOH) molarity (M) of 12 demonstrated superior performance. Impressively, the compressive strength exceeding 40 MPa was achieved with the amalgamation of M 12 and 50% basalt powder additive. However, the workability experienced a notable reduction at the fiber ratios of 2% and 3%. The molarity concentrations did not impede the slump, workability, or setting time. A consistent setting time of 6 h was attained, and the desired workability was obtained without the need for a superplasticizer. For achieving the optimal triad of the workability, setting time, and strength, while maximizing the environmental advantages of GPC, the recommendation is to incorporate a distinct combination comprising 1–2% glass fibers (with 12 mm length), M 12, and 50% basalt powder into the mixture formulation.

Recycling of Silicomanganese Slag and Fly Ash for Preparation of Environment-Friendly Foamed Ceramics.

In order to reduce the manufacturing cost of foamed ceramics and expand the application scope of industrial solid waste, in this study, a new type of environment-friendly foamed ceramics was prepared using direct high-temperature foaming with waste silicomanganese slag (SMS) and fly ash (FA) as raw materials and silicon carbide (SiC) as a foaming agent. The influence of SMS content, SiC content, and sintering temperature on the characteristics and microstructure of the specimen were explored. More concretely, the compressive strength, pore morphology, bulk density, and crystalline composition of the foamed ceramics were discussed. The foaming mechanism was also further analyzed. The results showed that including 20% SMS significantly reduced the melt's viscosity and stimulated bubble expansion. This, in turn, facilitated the creation of a porous structure. Moreover, it was noted that samples containing 20% SMS exhibited an anorthite phase when sintered at 1110 °C, resulting in enhanced compressive strength. The bulk density and compressive strength of the foamed ceramics decreased with an increase in the sintering temperature and SiC content. This trend was primarily attributed to the higher total porosity and the insufficient support of the pore wall to the matrix. The best all-around performance was achieved with 20 wt% SMS, 80 wt% FA as raw material, SiC addition of 1.0 wt%, and a sintering temperature of 1100 °C. Under these conditions, the compressive strength, bulk density, and total porosity of the foamed ceramics were 8.09 MPa, 0.57 g/cm3, and 71.04%, respectively. Taken together, the outstanding porous structure and mechanical properties of this foamed ceramic make it suitable for use as insulation or for building partition materials.

Fabrication of sustainable closed-cell aluminium foams using recycled fly ash and eggshell powder

Closed-cell aluminum foams are a novel materials which consists of unique properties such as good mechanical strength combining low mass and high stiffness, high energy and sound absorption, corrosion resistance, and recyclability. In spite of these potential properties, the usage of expensive constituents (stabilizing and foaming agents) and processing methods of making foams hinder its wide spread usage in industrial applications. This work involves the use of cost-effective constituents for processing aluminium foams by stir casting technique. The industrial waste fly ash (Class-F) is used as a source of stabilizing agent and for the first time the viability of waste chicken egg shell is used as a foaming agent to produce sustainable aluminium foams. Ex-situ characterization investigations are carried out on the manufactured foams in accordance with industry standards. It is evident that the produced foams have a fine cell structures with appreciable compressive strength and energy absorption characteristics. The experimental findings indicate that eggshell powder can be used as a cost-effective foaming agent for synthesizing aluminium foams and fly ash as foam stabilizing agent.

Novel porous ambient temperature cured fly ash geopolymer for lead adsorption from wastewaters

ABSTRACT This paper discusses the ability of the fly ash (FA) and abmbient cured Alkali activated Fly ash geopolymer (FAAG) for sequestering Pb (II) ions from aqueous solution. Various physiochemical properties such as the influence of pH and contact time were investigated for achieving the conditions for maximum removal via batch mode using powdered samples. The adsorbents were characterized by employing powder X-Ray diffraction, Attenuated Total Reflection Fourier Transform Infra-Red spectroscopy, and Scanning Electron Microscopy/EDAX before and after the treatment. The adsorption capacity of Pb2+ ions by raw FA and FAAG were examined by the Inductively coupled plasma mass spectrometry (ICP-MS). The results represented that the maximum adsorption capacity of Pb2+ ions by FAAG is 75 mg/g with attained equilibrium time of 120 min whereas raw fly ash at 150 min at 21.5 mg/g capacity. The pozzolanic reactivity of fly ash in water glass hardening resulted mainly N-A-S-H gel and traces of lead silicate due to the immobilization of lead in the network. This was conformed from the binding energy lines at 139.7 eV in XPS survey lines and lead silicate at 25 and 34° 2θ as identified in XRD phase assemblages. ICP-MS test results of leachate of lead immobilized geopolymer sample are devoid of lead ions and thus sorption sites of fly ash geopolymer lead to potential safety disposal of lead. Thus, recycling of fly ash into geopolymer by less energy intensive process and subsequent use in heavy metal disposal could achieve the concept of disposal waste and recycling, which could contribute to achieve the sustainable goals.