Utilization Of Fly Ash Research Articles

Effect of ball milling activation on CO2 mineralization performance in fly ash and fire resistance capabilities of mineralized product

Coal-fired power generation has always been a major energy supply source globally. However, a large amount of CO2 is emitted with the combustion of coal resources, and fly ash, a by-product of coal combustion, is also accumulated in large quantities. The application of CO2 mineralization in fly ash can not only reduce CO2 emission but also effectively manage industrial waste, thereby promoting environmental sustainability. This paper used the mechanical ball milling method to activate fly ash and investigated the effects of ball milling time and speed on the CO2 sequestration in fly ash. At 30 min ball milling time and 400 r/min ball milling speed, the modified fly ash achieves a good CO2 sequestration capacity of 81.70 gCO2/kgFA. Compared with raw fly ash, the CO2 consumption of treated fly ash is higher at 75.41 mmol/mL. The specific surface area and pore volume of treated fly ash are larger at 1.57 m2/g and 4.33 cm3/kg respectively, which is beneficial for enhancing mass transfer capacity and the carbonation effect. As the ratio of mineralized product/coal increases from 0.5 to 4, the crossing-point temperature increases from 157.20 °C to 165.15 °C. Based on the experimental results, the paper discussed the mechanism of ball milling activation to enhance the carbonation effect of fly ash. This study provides theoretical references for the environmentally friendly utilization of fly ash.

Optimization and Evaluation of Alkali Activated Fly Ash for Lightweight Aggregate Production

This study investigates the utilization of solid waste, specifically fly ash, and other materials to produce aggregates through geopolymerisation. The research aims to explore the properties of fly ash aggregates and assess their viability in concrete production. The objectives of the study encompass the preparation of aggregates using different proportions of fly ash and alkali activator such as sodium hydroxide and sodium silicate, alongside the casting of concrete cubes utilizing the artificial aggregate. The methodology employed involves the preparation of alkali activator, mix proportioning, and the subsequent processes of mixing, casting, crushing, and curing. Various ratios of fly ash to activator (2.5:1, 3:1, and 3.5:1) were investigated, with corresponding results obtained for properties such as abrasion value, impact value, bulk specific gravity, and water absorption. The findings reveal that the properties of the fly ash aggregates vary with different ratios, with notable differences observed in abrasion value, impact value, bulk specific gravity, and water absorption. For 2.5:1 abrasion value is 26.02%, impact value is 19.32%, bulk specific gravity 1.821 and water absorption 9.61%.For 3:1 abrasion value is 37.14%, impact value is 25.15%, bulk specific gravity 1.78 and water absorption 10.58%.For 3.5:1 abrasion value is 46.5%, imapct value is 32.87%, bulk specific gravity 1.648 and water absorption 12.83%. Casting cude using ratio 2.5:1, 28 day strength is 20.46 N/mm2.. This research project offers an eco-friendly solution for utilizing fly ash in the production of high-performance aggregates, contributing to sustainable construction practices. The implications of the findings include reduced environmental impact, enhanced resource efficiency, and the potential for resilient and environmentally conscious built environments. Further research and development in this area could lead to broader adoption of geopolymerized fly ash aggregates in the construction industry, paving the way for a more sustainable and Greener future.

A novel process for producing Al-Si alloy utilizing aluminum-silicon oxide extracted from coal fly ash

As a kind of solid waste rich in aluminum and silicon resources, the comprehensive utilization of coal fly ash (CFA) will be of great significance to reduce environmental pollution and improve economic benefits. This work proposed a facile and environmentally friendly cleaning process for producing Al-Si alloy by molten salt electrolysis from CFA extract, aluminum-silicon oxide (ASO). The dissolution behavior and dissolution reaction mechanism of ASO were studied by high temperature visual dissolution experiment, thermodynamics analysis and phase analysis. Due to the chemical reaction between ASO and cryolite-based melt, ASO powder dissolves rapidly in melt and the dissolution rate of ASO is not determined by the phase compositions but by the mass ratio of Al2O3/SiO2. For replenishing the oxide concentration in the electrolyte as quick as possible, the proper mass ratio of Al2O3/SiO2 is in the range of 0.75–7.5. The electrochemical co-reduction behavior of Si (IV) and Al (III) ions on the W electrode was performed by cyclic voltammetry and square wave voltammetry. The results indicated that the reduction of Si (IV) ion in the melt was a two-step irreversible process. Hypoeutectic Al-Si alloy and eutectic Al-Si alloy were prepared by galvanostatic electrolysis using ASO as raw material. This innovative technology can realize high-value recycling of CFA resources and low carbon emission, low energy consumption production of Al-Si alloy.

Effect of sintering temperature on ceramic membrane fabricated using coal flyash and natural clay for lignin recovery

This study explores the utilization of coal fly ash combined with natural clay as a precursor for creating ceramic membranes through the uniaxial compaction method, aiming at lignin separation. These membranes were sintered at varying temperatures from 600 to 1000 °C. Thermal Gravimetric Analysis (TGA) revealed the robust thermal stability of the membranes. Fourier Transform Infrared (FTIR) analysis affirmed the presence of silica and alumina within the membranes. X-ray Diffraction (XRD) peaks indicated the crystalline structure and the presence of metal oxides originating from the fly ash and clay components. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images illustrated the porous nature and rough surface of the ceramic membranes. The average pore radius of the fabricated membrane expanded from 43.12 to 7.91 nm with increasing temperature. Concurrently, membrane flux decreased from 4.13 to 0.96 ×10−6 m3/m2 s with higher temperatures. Lower contact angles indicated the hydrophilic properties of membranes. All membranes exhibited superior corrosion resistance and negative zeta potential, owing to the significant silica content in the fly ash. Lignin separation efficiency increased from 65 % to 81 % with increasing temperatures. The optimal sintering temperature was determined to be 800 °C, achieving a lignin recovery greater than 76 % and a membrane permeability of about 7×10−9 m3/m2 s kPa. Thus, the fly ash-clay-based ultrafiltration membranes synthesized in this study offer the potential for lignin biomass recovery from biorefinery effluent.

Utilization of Fly Ash and Bottom Ash as a Mixture for Making Paving Blocks

Utilization of Fly Ash and Bottom Ash as a Mixture for Making Paving Blocks

Development of high-performance fiber-reinforced concrete for drilling wellbore walls in highly mineralized strata and its sulfate attack resistanceattack resistance

Metakaolin has been incorporated into high-performance fiber-reinforced concrete for wellbore wall drilling to enhance its durability in strata with highly mineralized water. This study established a benchmark, utilizing fly ash, slag powder, and metakaolin as the factors in an orthogonal test to assess the durability of concrete against sulfate attack. The range analysis and an integrated balance method were employed to optimize the mix proportion, the optimized mix proportion of high-performance concrete was determined as concrete: cement: fly ash: slag powder: metakaolin: pumping agents: gravel: sand: water: polyvinyl alcohol = 1: 0.2: 0.075: 0.05: 0.106: 2.767: 1.556: 0.371: 0.003. The apparent and microscopic morphologies before and after the erosion of both the benchmark group and optimized mix proportion group were investigated. The triaxial permeability tests were conducted on these groups under varying confining pressures to elucidate concrete permeability trends. Additionally, a damage constitutive model for concrete under a sulfate attack was formulated based on the durability tests. This study could provide valuable insights into the industrial utilization of concrete in deep shafts within highly mineralized water strata in Northwestern China.

Water retention property and microscopic mechanism of shallow soil in inner dump improved by fly ash and polyacrylamide.

Improving the water retention property of shallow soil in the inner dump is the key step in the sustainable development of mines. In recent years, the use of fly ash to improve the structure of the inner dump and polyacrylamide as an additive to enhance water retention was an effective method. The article used a physical model test, filter paper method, and microstructure analysis method to compare and analyze the water retention property and microstructure of slope-improved soil with different fly ash and polyacrylamide content. The results show that the combined use of fly ash and polyacrylamide improved the water retention property of the amended soil. Fly ash and polyacrylamide had a greater effect on the low suction stage of the amended soil. Polyacrylamide reacted with water and bound soil particles to form aggregates, and the structural unit bodies were a block structure. Fly ash was non-sticky and was a matrix of fine particles, which weakened the bonding effect of polyacrylamide, and reduced the aggregates of soil particles, and the structural unit bodies were a flocculated structure of aggregates mixed with matrix. This, in turn, enhanced the capillary action and improved the water retention performance of the improved soil. In addition, polyacrylamide could connect water molecules, further enhancing the water retention property of the improved soil. The combined use of fly ash and polyacrylamide improved the available water content of improved soil, providing a viable and sustainable solution for improving the comprehensive utilization of fly ash, and laid the foundation for land reclamation at the inner dump.

Synthesis of Bulk-Nucleated Glass–Ceramics and Porous Glass–Ceramic Composites through Utilization of Fly Ashes

Synthesis of Bulk-Nucleated Glass–Ceramics and Porous Glass–Ceramic Composites through Utilization of Fly Ashes

Preparation of diopside-augite-based glass ceramics derived from magnesium slag and fly ash

Magnesium slag (MS) and fly ash (FA) are industrial wastes that must be utilized in a clean, effective, and massive method to avoid environmental pollution. In this study, the preparation of diopside-augite-based glass-ceramics was theoretically analyzed and experimentally conducted by disposal of MS and FA with chromium oxide (Cr2O3) as a nucleating agent. The thermodynamics analysis first indicated that pyroxene could be the main crystal phase of the target glass-ceramics for the co-utilization of both wastes. The experimental results indicated that the main phase in prepared glass-ceramics samples was diopside ([Ca(Mg, Fe, Al)(Si, Al)2O6], and the degree of glass network polymerization was enhanced with the FA in raw material increasing from 50 wt% to 65 wt%. Plus, the crystal size of the prepared glass-ceramics was gradually refined by increasing the FA. The optimized conditions were given as controlling nucleation at 790 °C for 2 h and crystallization at 929 °C for 2 h of the parent glass that derived from 40 wt% MS and 60 wt% FA as raw materials, 1 wt% Cr2O3 as nucleating agent. The resulting glass-ceramics had excellent properties and chemical stability, such as a density of 3.11 g cm−3, bending strength of 101.98 MPa, acid resistance of 98.34 %, and alkali resistance of 99.53 %. This study provided a route to produce eco-friendly glass-ceramics material for architectural decoration by high-efficiency utilization of MS and FA.

Effect of Al(OH)3 prepared from fly ash on the structural and catalytic properties of g-C3N4-based materials

In order to find the optimal combination method of secondary utilization of fly ash and g-C3N4 modification, an efficient composite photocatalyst of γ-Al2O3/g-C3N4 was obtained by calcining the composite precursors of Al(OH)3/DCDA. The introduction of Al(OH)3 prepared by fly ash into the precursors causes hydrogen bonding interactions between Al(OH)3 and DCDA, which facilitate the removal of N atoms from the edges of the CN framework of g-C3N4 during condensation, and the composites prepared possess more cyano defects. In addition, γ-Al2O3 and g-C3N4 form a chemical bond at the interface, and this chemical bonding causes the density of the electron cloud in the vicinity of the N atoms to increase. Among them, the strongest chemical bonding between Al2O3 and g-C3N4 was observed in ACN-1, while the most cyanine defects were formed in ACN-1, which made ACN-1 exhibit the best photocatalytic degradation of methylene blue, which is 2.48 times higher than that of the pristine g-C3N4.

An effective utilization of raw fly ash obtained from thermal power plants using thermal spray technique to improve corrosion resistance for marine applications

Marine-grade steel structures in offshore environments often corrode due to the aggressive environmental conditions. Many ceramic materials can cater to this demand. However, as per economic and ecological concerns, fly ash (FA), an industrial waste, can be another strong contender to control corrosion. Therefore, the present study developed composite coatings of fly ash with additives ((50-48) wt.% Al2O3; 0–2 wt% carbon nanotube (CNT)) onto marine-grade steel using a plasma spray technique to improve its corrosion resistance. The microstructure of 1 wt% CNT-reinforced alumina-FA (1CAF) coating was denser than 2 wt% CNT-reinforced alumina-FA (2CAF) coating due to the uniform dispersion of CNT and, thereby, uniform remelting of coating at localized sites. Consequently, the microhardness and adhesion strength of the 1CAF coating were improved by ∼14.66 % and ∼15.96 %, respectively. Further, Rietveld's analysis of coatings showed that quartz, being the primary phase for corrosion control, was 19.23 ± 0.87 %, 16.33 ± 1.04 % and 14.60 ± 1.87 % for alumina-FA (AF), 1CAF, and 2CAF, respectively. The electrochemical impedance spectroscopy and the salt spray corrosion tests showed that 1CAF coating corrosion resistance was improved by ∼11.2 % compared to AF coating, even with a lower quartz phase (∼15.08 %) due to the densification of coating. This densification was due to the remelting by CNT to seal pores in the coating. Furthermore, for the same reason, an increase in coating resistance and charge transfer resistance of 1CAF coating by ∼80.9 % and ∼19.93 %, respectively, were seen in the equivalent circuit analysis, showing great promise in controlling interfacial corrosion. Further post-treatments like plasma or laser treatments can seal the coatings further to improve corrosion resistance. Therefore, such coatings are expected to withstand harsh, corrosive environments and are well-suited for marine applications.

Construction of coal fly ash-based spherical grain adsorbents and their adsorption characteristics on phenolic compounds

Addressing the significant emissions and severe pollution hazards posed by coal fly ash waste in the coal chemical industry, as well as the challenges in recovering phenolic substances from coal chemical wastewater, this study utilized coal fly ash as a raw material to construct two types of spherical grain adsorbents: coal fly ash and coal gangue spherical grain (CFAGsg) and coal fly ash and pyrite spherical grain (CFAPsg). The adsorption performance of CFAGsg and CFAPsg towards phenolic substances in coal chemical wastewater was investigated. The research results demonstrated that CFAGsg and CFAPsg exhibited adsorption capacities of 20.31 mg/L and 30.42 mg/L for phenol, respectively, and maintained stable adsorption performance even after multiple regeneration cycles. Further analysis using kinetic, isotherm, and thermodynamic models, along with various characterization techniques, revealed that the adsorption of phenol onto CFAGsg and CFAPsg was primarily governed by physical and chemical adsorption, involving an endothermic reaction. Moreover, the study on the adsorption mechanism of phenol revealed that the adsorption behavior of CFAGsg and CFAPsg was mainly driven by pore filling, π-π stacking, and hydrogen bonding. Additionally, hydrophobic interactions were involved in the adsorption of phenol onto CFAGsg, while surface complexation forces played a role in the adsorption of phenol onto CFAPsg. Overall, the research findings provide vital theoretical support and practical application prospects for the high-value utilization of coal fly ash and the clean production of the coal chemical industry.

Experimental analyses of CO2 sequestration potential in mineralized fly ash and its efficacy in mitigating coal spontaneous ignition risks in underground mine goafs

To effectively utilize fly ash solid waste and realize fly ash resource utilization, carbon sequestration and emission reduction, as well as mine fire prevention and suppression, this paper analyses the components of fly ash by X-ray fluorescence spectrometer (XRF), rheological experiments, the CO2 sequestration experiments by the mineralization of fly ash, thermogravimetric analysis experiments, and flame-retardant property experiments. Additionally, the changes in the physical structure and morphology of fly ash before and after mineralization were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The carbon sequestration capacity and fluidity of fly ash slurry, as well as the ability of mineralized fly ash slurry to inhibit spontaneous coal combustion are comprehensively investigated. The research results indicate that CO2 is sequestered as calcite on the fly ash surface after mineralization. The optimal CO2 sequestration capacity of fly ash is 65.12 kg/t when 0.5 mol/L NaHCO3 is used as an additive. The fluidity of mineralized fly ash slurry is greater than that of fly ash slurry, and the lower the water-cement ratio is, the worse the fluidity. Mineralized fly ash slurry with a water-cement ratio of 3:1 has a strong carbon sequestration capacity and high fluidity, making it suitable for preventing coal spontaneous ignition in mine goafs. Mineralized fly ash slurry exhibits a regular trend where the better the mineralization effect, the lower the CO release during the low-temperature oxidation stage of coal, and the higher the cross-point temperature. Mineralized fly ash slurry has a stronger ability to inhibit spontaneous coal combustion than does ordinary fly ash slurry.

Влияние технологических факторов на плотность и прочность зологазобетона

One of the promising areas of fly ash utilization is the production of cellular concretes. The experience of using cellular concrete products in construction has shown that they can successfully compete with most traditional materials combining high thermal insulation and structural properties. The paper examines the influence of technological factors: grinding, composition, water temperature and water solid ratio on the density and strength of the gas and gold cement. Purpose of the study. Determination of the influence of technological factors of production on the density and strength of ash gas concrete. Materials and methods. Portland cement, fly ash from Ekibastuz GRES-2, bassanite, and aluminum powder were used as starting materials. The composition of ash gas concrete with an average density of 700, 800 and 900 kg/m3 was developed according to the technical requirements of CH 277-80 – Instructions for the manufacture of cellular concrete products. The physical and mechanical properties of cellular concrete were determined in accordance with the technical requirements of the current standards. The result s and discussion. On the basis of the basic composition, the influence of technological factors on the density and strength of ash gas concrete has been studied. As a result of the research, it was found that the strength of samples with an average density of 700 kg/m3 reaches 3.5 MPa, and with an average density of 800 and 900 kg/m3 – 5.1 and 7.6 MPa, respectively. These indicators confirm that the samples obtained from mechanically activated gold cement binder according to the technical requirements of GOST 25485-2019 correspond to the structural and thermal insulation properties of cellular concrete. Resume. The physical and technical properties of raw materials, concrete mixtures and cellular concretes were studied using Ekibastuz GRES-2 ash as a fine filler. The study showed that production technological factors such as the dispersion and composition of the mixture, the water-solid ratio and the temperature of the mixing water have a significant effect on the density and strength of the ash gas concrete. Optimization of these parameters makes it possible to achieve the specified values of density and strength in the resulting material. Proposals for practical application and direction of future research. The possibility and expediency of using the ash of Ekibastuz GRES-2 as an additive in the manufacture of ash gas concrete has been established.

A Tribological investigation of fly ash particulate‐loaded E‐glass fiber reinforced interpenetrating polymer network composites

AbstractEnvironmentally‐friendly materials are increasingly sought in use of both structural and non‐structural applications. Most of the prominent places, particulates and fibers are exclusively utilized to reinforce polymeric composites, aiming to enhance their strength and provide effective protection against wear. Currently, one of the most pressing issues encountered in current industries are wear and tear, mostly happens during manufacturing and agricultural operations. To overcome this issue, the current study examines into exploring the effects of different weight ratios (0%, 1%, 3%, 5%, 7%, 9% by wt.%) of fly ash (FA) loading on the abrasive characteristics of Interpenetrating Polymer Networks (IPNs) composites strengthened with E‐Glass fibers. Abrasion tests, conducted in accordance with ASTM D99 standard which involves five control parameters: load, FA content, speed, sliding distance, and surface roughness. Experimental design utilized Taguchi's orthogonal array (L25), with opts ANOVA to identify significant control factors. Results indicate that the addition of FA substantially enhances the wear resistance of particulate‐loaded E‐Glass fiber reinforced IPN composites. Moreover, the specific wear rate is significantly influenced by the applied load and FA content. However experimental data suggests that optimal wear behavior for IPN composites occurs under the conditions of 50 N load, 3% FA content, 300 rpm speed, 4000 m sliding distance, and 0.3 μm disc roughness. Further, scanning electron microscopy was also employed to examine microstructural details to better know the micro‐mechanism behavior happens between the particulates with fiber and matrix reinforcement.Highlights Utilization of fly ash significantly enhances composite strength. IPN laminates fabricated with 0%–7% particulate loads. IPN laminates thoroughly evaluated through wear testing. DOE guided experimental design using L25 orthogonal array. SEM analysis reveals superior quality of fly ash‐loaded IPN.

Resource utilization of medical waste incineration fly ash to activate peroxydisulfate for tetracycline degradation: Synergy between adsorption and PDS activation

Medical waste incineration fly ash (MWI FA) is classified as a hazardous solid waste. Therefore, the development of recycling technologies to convert MWI FA into useful products is necessary and challenging. In this study, we developed a sustainable approach for preparing a catalyst through the pyrolysis of water-washed MWI FA (WW FA-x, where x corresponds to the pyrolysis temperature). Subsequently, it was applied as a potent peroxydisulfate (PDS) activator to remove tetracycline (TC) from water. The results showed that the WW FA-800 exhibited remarkable adsorption performance as well as highly efficient catalytic activation of PDS, with a 115 mg/g maximum TC adsorption capacity and 93.5% (reaction kinetic rate = 315 μmol/g/h) TC removal within 60 min. A synergistic effect was achieved by adsorption and PDS activation. TC degradation was primarily driven by non-radical (1O2 and electron transfer) processes. WW FA-800 possesses multiple active sites, including defects, π–π*, O–CO groups, Fe0, and Cu(I). Three possible pathways for TC decomposition have been proposed, with the majority of intermediates exhibiting less toxicity than TC. Furthermore, the WW FA/PDS system exhibited an excellent anti-interference ability, and universality in the degradation of various organic contaminants. Notably, energy consumption was minimal, approximately 2.80 kWh/(g·TC), and the leachability of heavy metals in the WW FA-800 was within acceptable limits. This study provides a MWI FA recycling route for the development of highly active catalysts.

Utilization of municipal solid waste incinerator fly ash under high temperature sintering and alkali excitation for use in cementitious material

It is crucial to have a secure and dependable approach to treat and reuse municipal solid waste incinerator (MSWI) fly ash to prevent potential hazards. High temperature sintering is regarded as an efficient method for solidifying heavy metals, and alkali excitation provides a practicable solution for utilizing MSWI fly ash. In this work, the activation mechanism of MSWI fly ash was figured out under high temperature sintering. Besides, the preparation and optimization of sintered MSWI fly ash with metakaolin for use in alkali–activated cementitious material were explored based on Box–Benhnken design (BBD), considering different modulus and alkali equivalent of alkaline activator, as well as different contents of sintered MSWI fly ash and metakaolin. The mechanical performance and alkali excitation mechanism of the cementitious material were investigated. The results showed that the pozzolanic activity of MSWI fly ash treated by high temperature sintering was increased by 81.7 %, which further was improved by alkali excitation. The optimal mix proportion of alkali–activated sintered MSWI fly ash–metakaolin cement mortar consisted of a modulus of 1.332, an alkali equivalent of 1 %, a sintered MSWI fly ash content of 20 %, and a metakaolin content of 10.5 %, whose flexural and compressive strength were 8.5 and 57.3 MPa, respectively. Moreover, SiO32− and OH− in alkaline activator and Al(OH)4–, SiO2(OH)22−, and SiO(OH)32− in metakaolin promoted Ca2+ in sintered MSWI fly ash to generate C–S–H and C–A–S–H. Finally, the alkali–activated mortar made from sintered MSWI fly ash demonstrated high safety and eco–friendliness, with a synthesis toxicity index (STI) of 25.59.

Coupled physicochemical dual-crosslinking Ti3C2Tx composite aerogels for the selective adsorption of gallium ions in acid fly ash leaching

Herein, in order to extract Ga3+ from acid fly ash leaching, we propose a functionalized Ti3C2Tx-based MXene composite aerogel adsorbent for Ga3+ adsorption. The prepared physicochemical dual-crosslinking network aerogel MPHG-40 possesses good Ga3+ adsorption performance (132.52 mg g−1) at the pH of 3 and Ga3+ initial concentration of 50 mg L−1 within 6 h. After five adsorption-desorption cycles, the material shows good mass retention and a 95.65 % retention of its initial adsorption capacity, compared to most reported adsorbents. The optimized adsorbent realized good selective adsorption of Ga3+ against Cu2+, Zn2+, Fe3+, and Al3+ in a simulated acid fly ash leaching with the selective coefficient of 8.63, 96.10, 4.49, and 28.30, respectively. The adsorption may comply with a combined mechanism of physical adsorption, electrostatic interactions, ion-exchange mechanism, and ligand chelation, dominated by chemical adsorption, as identified by theoretical calculations based on density functional theory and experimental data. The three-dimensional solid adsorbent constructed in this study provides a new strategy for selective adsorption of Ga3+, making it possible to be applied to solid waste utilization of fly ash.

Improving the performance of iron-rich calcium sulfoaluminate cement from municipal solid waste incineration fly ash through diverse pretreatment approaches

The utilization of municipal solid waste incineration fly ash (MSWI-FA) is environmentally significant. In this study, MSWI-FA was pretreated using organic acid solution and CO2 microbubble carbonation washing. The pretreated MSWI-FAs were then used to produce Iron-rich calcium sulfoaluminate (IR-CSA) cement at different substitution rates (CFA) for various raw materials. The evolution of iron phase distribution, mineral composition, and hydration of IR-CSA cement were investigated, alongside heavy metal migration. The results showed that the MSWI-FA-based IR-CSA clinker had suitable mineralogical phases. However, gehlenite in MSWI-FA reduced CaO availability in the clinker formation reaction, hindering the involvement of Fe2O3 in the ye'elimite formation reaction. The calcination temperature was increased to facilitate clinker and iron phase formation in the case of high CFA levels. CO2 microbubble carbonation washing pretreatment of MSWI-FA, with which the IR-CSA clinker achieved suitable pH values and alkali content, facilitated the early growth and chained evolution of ettringite, resulting in a denser microstructure and lower cumulative hydration heat. Consequently, the compressive strength of MSWI-FA-based IR-CSA cement increased, with a maximum gain of 43.65 MPa. Chromium content in the residual form increased, and heavy metal leaching was well below standard limits. This approach provides a new perspective for the purification treatment of MSWI-FA and its high-value, large-scale recycling in low-carbon cement.

SUSTAINABLE INVESTIGATION ON POND ASH-INDUCED COMPRESSED INTERLOCKING BRICKS

Investigating the sustainability of using pond ash in compressed interlocking bricks is a multi-faceted process that requires assessing environmental, economic, and social aspects. India churns out more than 200 million tonnes of untapped coal ash every year. Stone crusher plants and thermal power plants are exhibiting huge amounts of unutilized by-products which have started invading our environment negatively and could soon create hazardous impacts. This paper focuses on investigating a new emerging sustainable brick constituting all these waste substances. Unutilized stone dust from crushers of the Khordha Industrial Area and Ash (Pond ash and Fly ash) were collected from the NALCO Power Plant situated at Angul, Odisha, India. Pond ash Induced Compressed Interlocking Bricks (PAICIB) were fabricated having parent mix with pond ash & fly ash levels of 35% and 40% stone dust by weight, which was fixed after several trial mix experiments. Variation was done with the proportion of lime and cement to the parent mix. Compressive strength tests were conducted on day 7 and 28. The parent mix of 30cmx15cmx10cm PAICIB containing no cement and 10% hydrated lime by weight of parent mix sustained a compressive strength up to 5.5 N/mm2 (failure load of 204KN) and the water absorption was 17% after 28 days. The primary focus of this investigation is to utilize the waste materials for creating an eco-friendly brick that can meet the demand of the current rising population of populated countries like India. This work becomes a part of the “fly ash management and utilization mission” by NGT as the bricks are formed here using the disposed pond ash in rivers reducing water pollution too.