Carbon In Fly Ash Research Articles

Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials.

The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was able to remove unburnt carbon from fly ash by using the installed micro bubble nozzles and a whirl-type pump. The removal efficiency of unburnt carbon improved when prior forced stirring was carried out by a concrete mixer for 3 min, and a scavenger was added into the fly ash slurry at a density of about 60 wt%. It has also been confirmed that the method of circulating water is more effective than the method of not circulating water. The elements of the modified fly ash slurry (MFAS) have also been experimentally confirmed as not being too different from untreated fly ash, except for the fact that the content of unburned carbon is reduced. The compressive strength and drying shrinkage characteristics of concrete made with MFAS were investigated. The use of MFAS will reduce the performance of concrete compared to that of ordinary concrete. This shows that in a certain range (15–30%), the influence of MFAS on drying shrinkage is constant. The static elastic modulus and dynamic elastic modulus were also investigated. The above results show that the application of MFAS prepared by the flotation method to concrete is feasible.

Carbonation of High-Ca Fly Ashes under Flue Gas Conditions: Implications for Their Valorization in the Construction Industry

The utilization of high-calcium fly ashes (HCFA) from coal-fired power plants in the construction industry is problematic, since their high free lime contents can lead to durability problems. In this research, the carbonation of a high-CaO fly ash has been carried out using simulated flue gas and concentrated CO2, with the aim to assess the valorization potential of such materials in the construction industry. The results show that, at 7 bars total pressure, an up to 36% carbonation efficiency can be achieved in just 30 min when pure CO2 is used; a comparable result with flue gas requires about 4 h of reaction. On the other hand, experiments carried out at atmospheric pressure show significantly different carbonation efficiencies depending on the CO2 concentration of the gas used. All experiments resulted in a substantial reduction in the original free lime content, and after reaction times of 4 h (at atmospheric pressure) and pressures of 7 bars (for any reaction time >30 min), the final free lime values were low enough to comply with the requirements of European Standards for their utilization as additions in cement.

Effects of the air-staging degree on performances of a supercritical down-fired boiler at low loads: Air/particle flow, combustion, water wall temperature, energy conversion and NOx emissions

Low load operation of down-fired boilers has become the norm such that the comprehensive performances of such boilers at low loads need to be investigated to increase the energy conversion efficiency and reduce carbon and NOx emissions. In this work, cold-model air/particle flow experiments and industrial-scale trials were performed to study the effects of the air-staging degree (ASD) on the air/particle flow, combustion, water wall temperature, energy conversion and NOx emission characteristics of a 350 MW supercritical down-fired boiler at low loads. The experimental conditions are four different combinations of damper openings associated with the secondary-air, tertiary-air and OFA (i.e. 60%/40%/15%, 50%/50%/15%, 35%/70%/15% and 30%/55%/55%), and are referred to as ASD = I, II, III and IV, respectively. The results showed that, as the ASD was increased from I to IV, the injection effect of the secondary-air on the fuel-rich flow was weakened. In addition, the downward diffusion of the air/particle flow toward the furnace center increased, while the particle concentration near water wall decreased and the velocity decay was accelerated. Decreasing the ASD shortened the ignition distance of the fuel-rich flow, reduced the carbon in fly ash and slag and improved the boiler efficiency. At an ASD setting of I, a higher thermal load and increased temperature near the water wall were obtained in the lower furnace. These conditions gave the highest superheated and reheated steam temperatures of 568.1 and 570.7 °C, respectively. As the ASD was increased from II to III, the cooling effect of the tertiary-air reduced the maximum water wall temperature. The reduction, in turn, increased the regulating margin of superheating degree, which raised the steam temperature. Increasing the ASD from I to IV increased the specific coal consumption from 337.36 to 348.12 g·(kW·h)−1, indicating that the energy conversion efficiency of the unit was decreased. Additionally, the NOx emissions at the furnace exit were reduced from 770 to 528 mg/m3 at 6% O2. On the basis of the present results, an ASD setting of II is recommended to ensure the safe and economical operation of such units while minimizing environmental impact.

Mechanochemical bromination of unburned carbon in fly ash and its mercury removal mechanism: DFT study

The mechanochemical (MC) brominated fly ash is a cost-effective mercury removal adsorbent, in which unburned carbon (UBC) plays an important role. The MC bromination mechanism of UBC and its mercury removal mechanism were completely studied through the density functional theory (DFT) method. Various defects on zigzag and armchair edge models were constructed at the micro-scale to simulate the MC effect on UBC at the macro-scale. The results reveal that the intact surface of zigzag and armchair can be constructed into abundant defective structures by MC action. Compared with the complete surface, bromine is more favorable to bind on the defective surface, resulting in more and stronger C-Br covalent bonds and more active sites. These defective structures also have a promoting effect on mercury adsorption. For the bromine-embedded structure, although the appropriate defective structure accounts for less, it not only can promote the adsorption and oxidation of mercury by improving adsorption ability or decreasing the oxidation energy barrier but is also easier to generate. Due to defect types formed by MC interaction on the UBC surface are much more diverse and complex, this study provides the theoretical basis for further research.

Effects of the gas/particle flow and combustion characteristics on water-wall temperature and energy conversion in a supercritical down-fired boiler at different secondary-air distributions

To alleviate the over-temperature of water-wall and increase the energy conversion efficiency of supercritical down-fired boilers, cold-model air/particle flow experiments and in-situ trials were performed to investigate the effects of the secondary-air distribution wall-side deflection coefficient (ws) on air/particle flow and combustion characteristics. As ws increased from 0 to 0.33, the amount of air/particle flow diffused toward water-wall and the corresponding particle concentration both decreased, while the velocity decay was accelerated. At a ws of 0.16, due to prior ignition of fuel-rich flow and a longer flame stroke in lower furnace, the carbon in fly ash and slag were lowest. As ws increased, the thermal load was gradually focused at the furnace center, and the maximum value and deviation of water-wall temperature in lower furnace decreased. Consequently, the temperatures of superheated and reheated steam respectively increased from 542.7 °C to 543.9 °C–560.2 °C and 560.1 °C, respectively. Furthermore, increasing ws from 0 to 0.28 decreased the specific coal consumption from 346.29 to 341.09 g (kW h)−1, indicating the energy conversion efficiency was improved. However, adjusting ws had only a minimal effect on NOx emissions. A ws of 0.28 is recommended to optimize the water-wall temperature, pulverized-coal burnout, and economic performance.

Deciphering van der Waals interaction between polypropylene and carbonated fly ash from experimental and molecular simulation

Pollution emitted from power plants, including a considerable amount of fly ash (FA) and carbon dioxide (CO2), annually increases and is challenging from an environmentally friendly and sustainable point of view. To date, laboratory-scaled approaches cannot efficiently replace the FA-landfilling and mitigate the stress from CO2 emission. Here, a practically operatable fundamental work by combining carbonated FA (C-FA)—immobilizing CO2 in FA—and polypropylene (PP) matrix is reported and reveals abnormal mechanical and thermal features clarified by calculating van der Waals (vdW) interaction from an atomic scale. This is the first study wherein the interaction between instantaneous dipole moment-induced PP and fillers is simulated and examined. The vdW interactions at the (hetero)interfaces are –59.66, –82.30, and −224.39 kJ mol−1 Å−2 for PP, calcium oxide (CaO; before carbonation), and calcium carbonate (CaCO3; after carbonation), respectively, which provides concrete theoretical support for interesting findings such as the independence of tensile strength on filler loadings and “well-grown” interface-induced higher conductivity characteristics of the composites. Therefore, this work can offer practical solutions to mitigate pollution, provide a new perspective on fundamental physical interactions, and guide the development of practical next-generation composite materials.

In-furnace flow field, coal combustion and NOx emission characteristics regarding the staged-air location in a cascade-arch down-fired furnace

A cascade-arch-firing low-NOx and high-burnout configuration (CLHC) is developed to strengthen low-NOx combustion and maintain high burnout in down-fired furnaces. Numerical simulations of the in-furnace flow field, coal combustion, and NOx formation are performed in a 600 MWe down-fired furnace to evaluate the staged-air location's effect on the low-NOx and high-burnout performance. The furnace, which is in service with a deep-air-staging multi-injection and multi-stage combustion technology (MIMSCT), was modified with the CLHC combustion system for the present simulations. Various staged-air location coefficients of CH = 0.65, 0.70, 0.75 and 0.80 were analysed. Moving downward staged-air to enlarge CH initially improves but then deteriorates the in-furnace flow-field symmetry. Similar changes in the gas temperature and species distribution patterns in the furnace are evident. As CH increases from 0.65 to 0.75, levels of the residual O2 concentration, carbon content in fly ash, and NOx emissions at the furnace outlet decline continuously. The highest setting CH = 0.80 generates severely asymmetric combustion accompanied by poor performance indexes, raising the unburnt rate and NOx emissions by 20–30%. The staged-air location of CH = 0.75 achieves a symmetric flow-field pattern, satisfactory low NOx emissions of ~670 mg/m3 at 6% O2 and high-burnout performance with carbon in fly ash of 5%. NOx emissions are reduced by 26% without affecting burnout in comparison to the currently advanced deep-air-staging MIMSCT.

Carbonation curing of cement mortars incorporating carbonated fly ash for performance improvement and CO2 sequestration

Carbonation treatment of fly ash (FA) is proposed as a promising method for stabilization of hazardous residues and CO2 sequestration. This paper aims to investigate the performance of cement mortar incorporating carbonated FA and the synergistic effect with carbonation curing. The results show that the content of free CaO and the hydration heat were reduced apparently by carbonation treatment. The synergy of carbonation treatment and carbonation curing compensated for the strength loss caused by FA incorporation, but can also delayed strength development brought by pozzolanic effect. CO32- on the surface of FA introduced by carbonation treatment competed with Cl− for binding AFm, consequently lead to decreased resistance of chloride ion penetration. Carbonation curing mitigated this degradation by improving the pore structure of cement mortar significantly. In summary, carbonation curing can be an appropriate complement to carbonation treatment of FA for performance improvement of cement-based materials and more efficient CO2 sequestration.

Interaction mechanism between gaseous arsenic and the unburned carbon in coal-fired fly ash: A DFT combined thermodynamics study

Based on the density functional theory (DFT) combined thermodynamics method, the flue gas arsenic forms from the coal-fired power plants were successfully confirmed at different temperature ranges, and the interaction mechanism of the fly ash unburned carbon (UBC) components on different gaseous arsenic species were also investigated. The content of trivalent arsenic (As3+) is the highest in flue gas, and its morphological distribution is significantly affected by the flue gas temperature. When the flue gas temperature is lower than 900 K, the As2O3 molecules are dominant in the trigonal bipyramid type. While when the temperature exceeds 900 K, the priority structure of As2O3 is chain type > horn type > trigonal bipyramid type in turn. This paper has verified the feasibility for the adsorption of flue gas arsenic via the unburned carbon in fly ash, and the performance of the zigzag carbon surface is always better than the armchair surface. This paper provides theoretical support for arsenic removal in coal-fired power plants, and also provides some new ideas for the secondary utilization of fly ash and the development of carbon-based arsenic removal adsorbent.

Soil and plant growth response and trace elements accumulation in sweet corn and snow pea grown under fresh and carbonated coal fly ash amendment

AbstractWith the recent focus of using coal combustion residue fly ash in mineral carbonation for C capture, an end product, carbonated coal fly ash is generated. The physicochemical changes occur in fly ash during carbonation is hypothesized to improve its soil application potential compared to original fly ash. Therefore, in the present study, we tested carbonated coal fly ash against non‐carbonated (fresh) ash for its effect on soil, plant production, and elemental accumulation in plant parts. Plant pots of sweet corn (Zea mays L.) and snow pea (Pisum sativum L.) added with fresh or carbonated Australian coal fly ash to sandy loam Podosol soil at 5% (w/w) and 10% (w/w) mixing rates were used in the study. Alkalinity of fly ashes attenuated the strong acidity of the soil into weakly acidic to slightly alkaline ranges. Either fresh or carbonated fly ashes added trace elements such as B, Fe, Mn, Zn, Cu, Cd, Mo, Cr, Pb, and Ni into the soil which significantly enhanced the plant growth and yield compared to fly ash absent pots. Accumulation of heavy metals in plant parts were observed in fly ash‐treated pots. Fresh fly ash at 10% (w/w) application rate increased the soil salinity above admissible range and retarded the crop growth and yield. Carbonated fly ash continued to enhance the crop production of sweet corn and snow pea up to 10% (w/w) mixing rate. Carbonation has improved the fly ash from its original state to make it a safer soil amendment at higher dosages such as 10% (w/w).

Fly Ash Carbon Anodes for Alkali Metal-Ion Batteries.

Graphite has become a critical material because of its essential role in the lithium-ion battery (LIB) industry. However, the synthesis of graphite requires an energy-intensive thermal treatment. Also, when used in sodium-ion and potassium-ion batteries (SIBs and PIBs), the graphite anode shows poor capacities and cycling stability, which hinders the development of next-generation battery technologies. Finding suitable anode materials for commercial alkali metal-ion batteries is not only urgent for the energy storage industry, but is also important for economic and sustainable development. In this work, we use fly ash carbon (FAC), a residue of crude oil combustion, as an anode material for alkali metal-ion batteries. The FAC anodes show relatively high capacities and excellent cycling stability. The charge storage mechanism of FAC anode is shown to be intercalation coupled with redox reactions of oxygen functional groups. This work shows that FAC is a promising scalable anode material for alkali metal-ion batteries.

Annealing effect on structural and optical properties of nanostructured carbon of oil fly ash modified titania thin-film

Dopants and crystallisation influence the photocatalytic performance of eco-friendly titania nanocomposites and consequently improve the quality of applications using titania nanocomposites. In this work, oil fly ash was used as the starting material for producing carbon nanomaterials prepared by high-energy ball milling in an acetic acid medium. Titania/carbon from a carbonaceous oil fly ash (TiO2/COFA) nanocomposite thin-film was fabricated on glass substrates via the spin-coating method. The obtained nanocomposites were then treated using advanced heat technology, where pressure, temperature rate and time duration were controlled. The structural, morphological, optical, and photoluminescence properties of annealed TiO2/COFA thin films are revealed for the first time. Between 300 and 500 °C, energy dispersive X-ray spectroscopy (EDS) analysis showed the successful doping of 7 wt% carbon nanoparticles in the TiO2 films. Structural development occurred in the anatase phase, including a decrease in the internal lattice strain and dislocation density and an increase in the crystallite size, leading to improved TiO2/COFA thin films as confirmed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) images. According to the optical investigations, there were increases in the absorbance, transmittance, and band gap of vacuum-annealed TiO2/COFA thin films with increasing annealing temperatures. The annealed thin films had a higher Urbach’s energy, and the photoluminescence intensities increased at 500 °C, indicating an abundance of defect-induced local electronic states and, subsequently, an improvement in the optical performance of the layers. These results suggest that the nanocomposite thin films may have potential for use as eco-friendly light-harvesting layers in solar cell components.

Coke preheating combustion study on NOx and SO2 emission

Aiming to further investigate preheating combustion technology on pollutants reduction impacts, a wider preheating temperature 600–1400 °C was conducted and the NOx and SO2 two pollutants emission were tested. Results showed that preheating combustion was an effective de-NOx technology but invalid for de-SO2. The increase of preheating temperature can boost NOx reduction and carbon burn off rate. The higher the preheating temperature, the larger the NOx reduction amplitude. When increasing the preheating temperature from 800 °C to 1400 °C, the NOx reduction rate could reach 20.2% and fly ash carbon could reduce 27.9% respectively. NO was the major composition in NOx. However, NO was decreased remarkably but NO2 increased by a certain margin in fuel-rich condition. To achieve ultra-low pollutants emission, NO2 should also be aroused attention besides NO.

Utilization of low-calcium fly ash via direct aqueous carbonation with a low-energy input: Determination of carbonation reaction and evaluation of the potential for CO2 sequestration and utilization

Environmental impacts from coal-fired power generation that produces large amounts of CO2 and fly ash are of great interest. To reduce negative environmental impacts, fly ash utilization was investigated via a direct aqueous carbonation with a low-energy input in which the alkali calcium content in the fly ash reacted with CO2 to form carbonate. Raw fly ash was characterized to understand the potential for direct aqueous carbonation of fly ash. The performance of the fly ash as a calcium source for direct aqueous carbonation at atmospheric pressure was investigated for different solid–liquid ratios and introduced CO2 concentrations. Variations in fly ash elemental composition, reaction solution pH, CO2 concentration in the reactor outlet, CO2 uptake efficiency, CaCO3 content and degree of carbonation were used to illustrate this process reaction. The maximum CO2 uptake efficiency was ~0.016 g-CO2/g-fly ash. This value was compared with previous studies, and the CO2 uptake efficiency was comparable despite the use of a low-energy input method, i.e., direct aqueous carbonation with atmospheric pressure and unconcentrated CO2. The calculated maximum degree of carbonation was 31.0%, which corresponds to 0.0063 g-CO2/g-fly ash. Carbonated product characterization confirmed the carbonation reaction mechanism and safety for further utilization. A comparison of CO2 uptake efficiency in this work with previous work, and considering the energy input and reactive species content, is provided. An assessment of the CO2 reduction potential is provided.

Study on NO emissions during the coupling process of preheating-combustion of pulverized coal with multi-air staging

Controlling the NOx formation during the combustion process is the most direct and efficient way to minimize NOx emissions, so low NOx combustion technology is essential. In this work, in order to develop multi-air staging pulverized coal (PC) preheating-combustion technology and further optimize the preheating-combustion burner, a 35 kW PC preheating-combustion test system was built, and three types of burners with different outer secondary air (OSA) injection structures were designed. Using Huangling bituminous coal (HL coal) and Wuhai bituminous coal (WH coal), the coupling process of PC preheating-combustion with multi-air staging on NOx emissions was studied systematically. The results showed that the depth furnace air staging could further reduce NOx emissions. When close-coupled over-fire air (CCOFA) and separated over-fire air (SOFA) were applied simultaneously, a significant NOx reduction of 70.2% could be reached 217 mg m−3. Compared with the NOx emissions, the unburned carbon in fly ash presented opposite tendency. Compared to burner II (high-speed swirl jet) and III (low-speed axial jet), burner I (high-speed axial jet) showed the lowest NOx emissions under the multi-air staging preheating-combustion conditions. Furthermore, the depth furnace air staging had greater denitrification potential for high-quality bituminous coal.

Electrical and Mechanical Effects of Carbon Powder in F and C Class Fly Ash Reinforced Mortars

This study was carried out to investigate the effects of carbon powder on the electrical conductivity and mechanical properties of fly ash reinforced mortars used as mineral additives. Samples were created by replacing CEM I 42.5 R cement, water and Cen standard sand with 0.5%, 1%, 3% carbon powder by weight. Class F and Class C fly ash were added separately at the rate of 10% and 20% by weight of cement to the formed carbon dust series. 20 different series were created with the reference sample. Electrical resistivity measurements were made to the oven dry and natural humid conditions of the samples that completed their 7,28 and 56 days curing period. The physical properties of the samples were determined and bending and compressive strength tests were made. The results obtained were evaluated and it was observed that with the increase of the carbon dust ratio compared to the reference sample, the electrical conductivity ratio increased, but the conductivity decreased depending on the time. It has been observed that the F class fly ash combination series are more conductive than the C class combination series. It was observed that the compressive and tensile strength values ​​of F and C class fly ash carbon dust free samples increased with time. Carbon dust has been shown to increase compressive strength in fly ashless series. There was an increase in the 56th day reading in the tensile strength. It was observed that F class increased tensile and compressive strength in fly ash and carbon dust combination series. Keywords: Carbon dust, F class fly ash, C class fly ash, Electrical conductivity. DOI: 10.7176/CER/13-2-02 Publication date: April 30 th 2021

Numerical and experimental study on co-firing of low volatile coal in a 330 MW tangentially fired boiler

Burnout related problem occurs in the utility boiler burning low volatile coals. The in-furnace co-firing of low volatile coal (LV) experiments and simulation were carried out in a tangentially fired PC furnace to investigate the effect of co-firing ratio, injection position and particle size on NOx emission and carbon in fly ash (Cfh). The results of full-scale experiment show that Cfh increases from 2.16% to 4.21% as the LV co-firing ratio rises from 33% to 50%, while the NOx emission increases from 356.0 mg/Nm3 to 385.2 mg/Nm3 (@6% O2). The model is validated against the experimental data. The numerical simulation results show that NOx increases from 308 mg/Nm3 to 567 mg/Nm3 when the co-firing ratio of LV increases from 0% to 100%, while Cfh increases from 1.20% to 7.15%. It is found that the contribution of top two layers (E and F) to the total Cfh is significantly higher than that of the other layers. Under the working conditions of burning bituminous coal in the bottom layer and lean coal (particle size 70 μm) in the upper five layers, Cfh is 5.4%. When the particle size of lean coal in the five layers is reduced to 40 μm, Cfh rapidly decreases to 2.0%. And the Cfh can be reduced to 2.5% when only the top two layers feeding lean coal with smaller particle size (40 μm). Only 40% marginal cost of coal grinding is needed to reach the marginal benefit corresponding to 83% Cfh improvement while all layers of LV coal are ground into the small size.

Impact of the upper/lower furnace depth ratio on the strengthened low‐NOx combustion performance in a two‐stage W‐shaped flame furnace

AbstractFor achieving the strengthened low‐NOx combustion plus high burnout in W‐shaped flame furnaces, a cascade‐arch low‐NOx and high‐burnout configuration (CLHC) is realized by positioning two burner layers in a 600 MWe furnace. The gas/particle flow, combustion, and NOx emission characteristics in the furnace are numerically evaluated at four upper/lower furnace depth ratios of CW = 0.458, 0.500, 0.529, and 0.558 (CW signifying the furnace throat shrinkage level) so as to disclose the impact of the furnace throat shrinkage level on the overall furnace performance and meanwhile establish an available CW setup. Increasing CW initially updates but then deteriorates the low‐NOx combustion performance. At the narrowest CW = 0.485 setup, the gained slightly asymmetric combustion shows relatively lower burnout loss but higher NOx emissions, while the widest CW = 0.558 setup forms severely asymmetric combustion with apparently raised carbon in fly ash but relatively lower NOx emissions. At moderate setups of CW = 0.500 and 0.529, a symmetrical combustion pattern develops, showing the low‐NOx and high‐burnout performance characterized as NOx emissions of 700–707 mg/m3 (6% O2) and carbon content in fly ash of 5.4–5.5%. In comparison to CW = 0.500, the larger downward flame penetration, higher flame fullness, and lower CO emission at CW = 0.529 suggest that a reasonable upper/lower furnace depth ratio prefers CW = 0.529. Compared with a currently advanced low‐NOx combustion technology, the CLHC lowers again NOx emissions by about 200 mg/m3 (6% O2) while maintaining high burnout, which confirms the CLHC's availability.

Combined operation mode of sub-critical W-flame boiler and coal mill optimized numerical simulation

The flow, combustion, heat transfer and NOx emission characteristics of a 600 MW subcritical W-flame boiler were numerically simulated under different combined operation modes of coal mills, and compared with the measured results. The results show that the combustion, average residence time, burnout rate, NOx emission characteristics and temperature distribution near the side wall of pulverized coal particles in the furnace have different effects on the combined operation mode of pulverized coal. In the combustion efficiency of give attention to two or more things, screen superheater section of fly ash carbon content and flue gas temperature of entrance at the same time, compared with six coal mill run at the same time, 5 coal mill run, shut down near the side wall of the coal mill is beneficial to reduce NOx emission concentration, to achieve the emission reduction, at the same time under the wing wall and side wall area chamber of a stove or furnace slagging significantly reduce.

Removal of Uranium238 Ions from Contaminated Ground Water Contain NORM by Adsorption on Fly Ash Carbon: Equilibrium, Kinetic and Thermodynamic Studies.

Water purification from radionuclides by using an effective and low-cost adsorbent which it is produced in high quantities from the fuel combustion in power stations where mazote, coal and other fuels extensively used. Fly ash’s particles were used to investigate the removal of uranium238 ions, in the concentration range of 27.9, 55.8, 111.6 Bq/l from ground water. In order to research the effect of various parameters including pH, contact time, initial metal ion concentration, dose adsorbent and temperatures batch tests have been performed in adsorption. The optimum contact time was 30 minutes and the appropriate pH was found to be 4.5. Temperature effects on kinetics and equilibrium were closely investigated in fly ash spores. Endothermic findings and a temperature rise resulted in an increase in the adsorption rate of uranium239. Data was applied to different temperatures (293, 303 and 313 K) with the isotherms Langmuir, Freundlich and Dubinin – Radushkevich. The best way to explain the data was to find the Langmuir Adsorption Model. Adsorption kinetics have been studied in pseudo-first, pseudo-second order. A pseudo-second-order mechanism was the best in fitting the data. Thermodynamic parameters; ΔH°, ΔG°, and ΔS° have been studied. SEM is used to assess morphological changed in the fly ash surfaces following adsorption of uranium238 ions.