Search

This paper presents an experimental investigation on the durability properties of metakaolin (MK) and bottom ash (BA) blended geopolymer under different environmental exposure. The blended geopolymer concrete (GPC) was prepared with sodium based alkaline activators under ambient curing temperature. The concentration of sodium hydroxide used was 8 M. The ratio of sodium silicate to sodium hydroxide was kept as 2.0. The performance of blended geopolymer concrete was compared with conventional concrete (CC). The test results reveal that blended geopolymer concrete develops a better performance against sulphate and acid resistance. Also, MK-BA GPC shows enhanced performance over the conventional concrete in terms of sorptivity, rapid chloride and water absorption.

Phosphorus recovery from sludge incinerated bottom ash (SIBA) is one of the effective methods to realize phosphorus reuse. Extracting phosphorus efficiently from SIBA is the first step. In this stu...

This study presents the synergy of high ash coal with different biomass when blended in different ratios for co-gasification using a fluidized bed gasifier. The moisture, CO2, oxygen, hydrogen and numerous other compounds have synergetic effects on the co-gasification because of affinity to heat and prone to reaction. The mineral constituents, discrete mineral species and ion-exchangeable elements present in coal, biomass and bottom ash residue have been identified by XRD, XRF, FTIR and SEM-EDX. The catalytic effects of mineral, major oxides, halides and chlorites content on co-gasification have been assessed. The mineral (e.g. calcite, dolomite, hematite, etc.) present in the high ash coal and biomass plays a catalytic role. Other minerals (e.g. quartz, sulfide, kaolinite and phosphates) negatively influence co-gasification and product gas composition. The positive relationship of CaO, MgO and Fe2O3 with CCE, CGE and increasing heat values also supports major oxides catalytic role. The blend of press mud and high ash coal has given better results due to more Ca, K, Mg and Na elements. SEM microphotographs reveal catalytic effects at the micro-level, indicated by the extensive cracking of hydrocarbon compounds. The empirical models proposed for estimation of catalytic effects of minerals on co-gasification.

The present work deals with a cost-effective removal of methylene blue (MB) dye utilizing a low-cost adsorbent, seawater based geopolymer (SW-GP) in the treatment of wastewater. It is prepared from different industrial by-products as raw materials such as coal fly ash (Class F), bottom ash (BA), and Ground Granulated Blast-furnace Slag (GGBS) by factorial mix design. The adsorbent was characterized using the Fourier-Transform Infra-Red spectroscopy (FT-IR) to identify the major functional groups. The percentage of elemental composition was calculated by X-ray fluorescence (XRF) analysis. The Scanning Electron Microscope (SEM) analysis confirms the presence of mullite and quartz in the adsorbent. The surface area was calculated by the Brunauer–Emmett–Teller (BET) analysis as 11.85 m2/g and pore size distribution was calculated by the Barrett–Joyner–Halenda (BJH) model to be 0.025 cm3/g. At an optimum dosage (0.08 g/L) of the geopolymer, the efficiency of MB color removal i.e. the adsorption capacity of the adsorbent was found as 81.36% and 59.52 mg/g respectively. Seawater based geopolymer (SW-GP) performs as an efficient adsorbent because of its less energy consumption in synthesis, larger surface area, and longer thermal stability up to 800°C for the removal of methylene blue in an aqueous medium by adsorption process.

Combustion of phosphorus-rich residual streams can produce nutrient-rich ashes and these can be used either in further processing or as materials for direct nutrient recycling. The latter requires knowledge on morphological parameters of such ash particles that may impact plant growth, nutrient availability, and soil physical properties. The present work aims to determine the porosity, pore size, and specific surface area of ash particles, and discuss these properties in light of literature concerning interaction with soil water and plant roots. Bottom ash particles from combustion of sewage sludge and wheat straw and their co-combustion were analysed with X-ray microtomography. Image analysis provided information on morphology, specific surface area, porosity, and pore structure on a micrometre scale resolution. Co-combusting sewage sludge with wheat straw resulted in differences in ash particles' porosity and pore structure compared to combustion of pure fuels. Pure wheat straw ash displayed 62 vol% porosity while there was no apparent difference between 10 wt% or 30 wt% mixtures of sewage sludge, with a porosity of 29–31 vol%. Open pore volume comprise the largest part of the porosity (72–99 vol%) enabling interaction between surrounding pore water and nutrients. Overall, the ash particles display large open volume fractions and thin particle walls which may lead to rapid weathering and extensive interaction with soil water. The particles generally contained pore openings over 200 µm towards the surroundings, which provide opportunities for interaction with microbes and roots from a variety of plant species in addition to nutrient transport by soil water.

Palm oil bottom ash utilization from mill boilers as CO 2 adsorbent has been in use for few years. This study aims to examine adsorbent characteristics and capabilities of bottom ash produced from boiler combustion in palm oil industry for CO 2 adsorption before and after utilization, such as compound functional group using the Fourier Transform Infra-Red (FT-IR) spectrophotometer, adsorbent morphology through Scanning Electron Microscopy (SEM), and compound amount using Energy Dispersive X-Ray Spectroscopy (EDX). The CO 2 adsorption was carried out in fixed-bed column. Process variables consist of volumetric flow rate, contact time and bed height. Results showed that SiO 2 compounds in the heterogeneous form with average particle size of 1073 nm, as supported by FT-IR spectrum finding indicating SiO 2 signal at wavelength of 958–954 cm –1 . Additionally, EDX analysis showed Silica and Oxygen content of 11.88% and 36.90%, resulting 70% CO 2 adsorption capacity of 0.350 mg/g at discharge of 5 L/min, contact time of 40 min, and bed height of 12 cm. Langmuir isotherm model was obtained with R 2 of 0.998, q m of 1.588, and k L of 0.144. Meanwhile, the kinetic model followed a simple first-order prototypical with R 2 of 0.952, C0 2 of 0.260, and k 1 of 0.006.

The behavior of mercury (Hg) species during thermal cogeneration was analyzed in a 10 MWh solid refuse fuel (SRF) utility boiler using a selective non-catalytic reduction unit, semi-dry reactor, and fabric filter with activated carbon injection for air pollution control from the facility. The annual Hg inflow into this facility is 24.2 (from 9.2 to 33.3) kg. The Hg species in flue-gas at inlet and outlet of the air pollution control devices (APCDs) were observed to be a mixture of 14.4 µg-Hg/Sm3 of particulate mercury, 2.6 µg-Hg/Sm3 of oxidized mercury, and 15.6 µg-Hg/Sm3 of elemental mercury and another mixture of 0.0 of particulate mercury, 0.3 of oxidized mercury, and 11.0 of elemental mercury, respectively. Elemental mercury was the major component in the combustion residue. In the emission assessment, the mass distribution of Hg of fly ash, bottom ash, and stack emission was determined as 67% (16.2 kg/yr), 2.0% (0.47 kg/yr) and 31% (7.5 kg/yr), respectively. Although elemental mercury was captured by APCDs configuration, it is best to chemically capture the air-emission mercury. Evaluation of Hg stability was tested for the fly ash by sequential extraction procedure method.

Due to its large mineral fraction, incineration bottom ash (IBA) from municipal solid waste incineration is an interesting raw material that can be used for road construction or to produce secondary building materials. However, leaching chloride, sulfate, and potentially harmful heavy metals may cause problems in using IBA in civil engineering. Investigating leaching behavior is crucial for the assessment of the environmental compatibility of IBA applications. Various test procedures are available for that purpose. In the present study, a long-term leaching test of a wet-mechanically treated IBA was performed in a lysimeter for almost six years. While concentrations of chloride, sulfate and the majority of the heavy metals started to decrease rapidly with advancing liquid-to-solid ratio (L/S), antimony (Sb) and vanadium (V) behaved differently. At the beginning of the lysimeter test, the Sb and V concentrations were low, but after approximately one year of operation at an L/S ratio of around 0.8 L/kg, a steady increase was observed. It was shown that this increase is the result of low Ca concentrations due to the formation of CaCO3. With the data, the solubility products from Ca-antimonate and Ca-vanadate were calculated. The unusual leaching behavior of Sb and V should be kept in mind when considering field scenarios and evaluating the impact on the environment.

Catalytic pyrolysis offers a sustainable route to convert plastic wastes into fuel. We investigated the catalytic performance of coal ash (fly and bottom ash) at blending ratio of 5 wt%, and 15 wt% during pyrolysis of linear low-density polyethylene (LLDPE). The influence on activation energy and oil was characterized via thermogravimetric analyzer (TGA) and gas chromatography-mass spectrometry (GC-MS). Results have shown that 15 wt% bottom ash exhibited higher catalytic activity. The activation energy estimated by Coats-Redfern method decreased from 458.7 kJ·mol-1 to 437.8 kJ·mol-1, while the alicyclic hydrocarbon yield increased from 5.97% to 32.09%. This implies that CaO, which is abundant in bottom ash, could promote the conversion of LLDPE. Furthermore, a cradle-to-factory gate life cycle assessment was performed to investigate three scenarios (non-catalytic pyrolysis, 15 wt% fly ash, and 15 wt% bottom ash) of LLDPE conversion strategies via a normalization and weighting approach. It was found that LLDPE pyrolysis with 15 wt% bottom ash also showed the lowest normalized score of 2.83, implying the lowest environmental impact. This work has demonstrated that the recycling of coal ash, particularly bottom ash, as catalysts for LLDPE pyrolysis is effective.

Upaya pencegahan pembentukan air asam tambang dapat dilakukan dengan metode dry cover yang dilakukan dengan menutup batuan yang berpotensi membentuk asam (PAF) dengan batuan yang tidak berpotensi membentuk asam (NAF). Penelitian ini bertujuan untuk me ngetahui pengaruh penggunaan fly ash dan bottom ash sebagai NAF dalam mencegah pembentukan AAT dengan cara mengurangi kontak antara mineral sulfida dengan air dan oksigen. Metode Free Draining Column Leach Test digunakan untuk memprediksi pembentukan AAT yang terbentuk. Simulasi perbedaan perlakuan sampel digunakan dengan 2 variasi pelapisan sampel NAF dan 3 variasi pencampuran sampel NAF. Hasi lsimulasi menunjukkan bahwa dengan variasi pelapisan sampel NAF didapatkan kualitas air yang lebih baik. Penggunaan variasi pelapisanmeningkatkan nilai pH, menurunkan nilai TDS serta DHL sebagai hasil oksidasi pirit didalam batuan. Untuk menunjang hasil analisis kualitas air, penguji an statistika juga digunakan untuk mengetahui perbedaan dari variasi penggunaan fly ash dan bottom ash terhadap perubahan nilai pH, TDS dan DHL yang dihasilkan. Kata kunci : Fly ash, Bottom ash, pH, TDS, DHL ABSTRACT Acid mine drainage prevention efforts can be carried out by the method of the dry cover which is done by closing the rock that is potentially acid forming (PAF) with the non-potentially acid forming rock (NAF). This study aims to determine the effect of the fly ash and bottom ash as NAF in preventing the formation of AMD by reduce contact between the sulfide minerals with water and oxygen. The method of Free Draining Column Leach Test is used to predict the formation of A MD formed. Simulated difference in sample treatment is used with 2 variations in the coating samples of NAF and 3 variations of the mixing a sample of NAF. The simulation results show that with the variation of the coating sample of NAF obtained better water quality. The use of variations of the coating increases pH value, lower the value of TDS as well as DHL as a result of oxidation of pyrite. To support the results of water quality analysis, the statistics test is also used to determine the difference from the variation of the use of fly ash and bottom ash to change the pH value, TDS and DHL that is produced. Keywords : Fly ash, Bottom ash, pH, TDS, DHL

In order to study the emission characteristics of the products during the blending of antibiotic residues in coal-fired power plants, blending tests were performed on a 140 t/h circulating fluidized bed boiler. It was found that during combustion, 64 to 87.6% of Cr, As, and Pb are concentrated in the fly ash, and 11.4 to 35% are concentrated in the bottom ash. Only a small amount of these elements are captured by the desulfurization system or enter the environment. During the material distribution of the desulfurization system, trace elements are mostly concentrated in gypsum. In the desulfurization system, the proportion of Cr, As, Pb, Be, Mn, Co, Ni, Se, and Mo in the gypsum range from 82.8 to 99.9%, and the content has reached the level of ppm. When the blending ratio is controlled within 7%, the blending of antibiotic residues has little effect on the elemental composition of coal. The contents of Cr, Ni, Cu, Zn, and Ba in the products increased by 9.5 to 22.3%. This may mean when the blending ratio is increased, it will be harmful to the environment.

Crude oil ash is the residue that is produced during oil combustion for instance fly ash, bottom ash or boiler slag which was primarily produced from the combustion of coal. With growth in oil burning power station, huge amount of fly ash considered as organic materials which are normally disposed in an on-site disposal system without any commercialization purpose. Previous researchers have studied the extraction of silica from agricultural wastes such as palm ash and rice husk ash (RHA) and FA (fly ash) by using leaching treatment method. In this study, the weaker acid, citric acid solution was used to replace the strong acid in leaching treatment to process. Result showed that the loss on ignition materials can be decrease to 12%. Meanwhile the silica can be extracted up to 54.4% from FA using citric acid leaching treatment under the optimum reaction time of 60 minutes with solution temperature of 60°C and concentration of citric acid 5% receded by gradual combustion at 900°C for 3 hours. http://dx.doi.org/10.30572/2018/kje/100306

Fly ash dan bottom ash (FABA) merupakan limbah hasil sisa pembakaran batubara dari pembangkit listrik tenaga uap (PLTU). FABA yang dihasilkan akan terus meningkat seiring dengan meningkatnya kebutuhan energi listrik yang harus dipenuhi. Komposisi FABA secara umum berupa silika, alumina, oksida besi, dan senyawa oksida lainnya. Abu yang dihasilkan dari pembakaran batubara berpotensi secara ekonomis karena mengandung beberapa unsur berharga antara lain Ge, Ga, unsur tanah jarang (REY), Nb, Zr, V, Re, Au, Ag, dan logam dasar seperti Al. Karakteristik fisik dan kimia FABA merupakan aspek penting yang dapat memengaruhi, baik potensi penggunaan maupun metode pembuangan atau penyimpanan limbah yang akan dilakukan. Potensi pemanfaatan FABA telah banyak digunakan pada bidang geoteknik, salah satunya diaplikasikan sebagai material geopolimer. Selain itu, FABA juga mengandung cenosphere yang merupakan salah satu material bernilai ekonomis tinggi dan telah banyak diaplikasikan pada berbagai bidang industri. Berbagai teknik pemisahan material untuk meningkatkan potensi nilai guna FABA telah berhasil dikembangkan, antara lain metode ektraksi cenosphere, logam berharga serta unsur jejak seperti REY, juga unburned carbon.

The high concentration of SO2 and SO3 under oxy-fuel combustion atmosphere is conducive to the sulfation of alkali metals. In order to investigate the effect of SO2 and SO3 on the distribution of Na/S/Cl and ashes characteristics of Zhundong coal during oxy-fuel combustion, a series of experiments were carried out in a 50 kW CFB oxy-fuel combustor system. The results showed that both SO2 and SO3 could realize the sulfation reaction of NaCl. It would enhance the distribution of sodium to the bottom ash and the circulating ash, the chlorine to the flue gas, so as to reduce the content of sodium and chlorine in deposit. In addition, the contents of Ca and Mg increased in the deposits and decreased in the fly ashes as the SO2 and SO3 were added, while the contents of Fe were all decreased in the deposits and fly ashes. Compared with SO2, SO3 is more prone to the sulfation reaction. While increasing the addition of SO2 and SO3 could strengthen the sulfation reaction. In addition, the deposit and fly ash generated by Zhundong coal combustion could be divided into two parts: particles less than 10 μm formed by condensation of sodium, chlorine and other components; particles larger than 10 μm formed by crushing of coal ash. Introducing SO2 and SO3 made the surface structure of deposit more porous, but the BET surface area of fly ash declined. There was no obvious difference of particle size distribution of deposit.

Bed particle agglomeration and ash deposition in a 0.2 t/d circulating fluidized bed (CFB) gasifying high sodium Zhundong lignite (ZD) at different air equivalence ratios (ERs) were experimentally investigated. With quartz as bed material in the CFB at 900 °C, ZD within 3 mm in size was fed into the furnace and gasified at ERs 0.73–0.33. Two air-cooled probes were inserted in the furnace chamber (P1) and placed at the cyclone outlet (P2) respectively to simulate ash deposition. The bottom ash (BA), fly ash and ash deposited on probes were collected and analysed by using XRD, SEM-EDS, and an ash fusion analyser. At ER0.73 during gasification, agglomerates of bed particles were observed, since low melting-points sodium silicates sticking the bed particles together. Meanwhile, in the presence of NaFeSi2O6 and sodium silicate, char particles were found to have been coated by quartz and ash particles. Independent temperature-programmed ESEM imaging analysis showed these minerals became molten even at 800 °C, confirming their low melting-points. Agglomeration in BA became even severe as ER decreased, suggesting an aggravated agglomeration tendency. The fly ash mainly composed of calcium sulphate and Na-bearing minerals, whose morphological and mineralogical features were independent of ERs. In addition, ash deposited on P2 under all gasification conditions was found to be rich in Na2SO4. However, the contents of NaCl and unburned carbon increased significantly as ERs decreased. This decreased the sintering tendency of deposited ash but promoted corrosion of the P2 probe tip as observed.

Aims: This study aimed to increase the utilization of biomass-derived from the waste of coconut and peanut shells by making them as briquettes, as an alternative to fuel. The scarcity of petroleum because of its increasingly limited existence encourages all parties to take part in the development and discovery of new alternative energies. This is expected to overcome one of the most important of the many problems facing this country. The method used in this research is to start with a literature study of materials from various sources about the benefits and manufacturing of briquettes from biomass waste as an alternative energy source to be further tested for quality. This involves a heat test, water content test, ash content test and determination of the flying matter. Results: The test results showed that natural gas emissions were below threshold, namely 0-30 ppm CO, 0-3.6 ppm H2S, and undetectable NOx. After evaluation, the results showed that with the addition of 30% of the biomass, the ignition time was reduced and the remaining unburned briquettes or bottom ash was reduced by 68.68%. Conclusion, significance, and impact of study: The results help the community and the parties involved related to appropriate bio briquettes technology. It also eventually becomes one of the solutions to assist the government in solving problems related to alternative fuels to petroleum.

Hydrogen (H2) production via biomass gasification has demonstrated to be a viable method to obtain environmental-friendly fuel. In this paper, steady-state modeling of palm kernel shell (PKS) steam gasification pilot-plant is developed and validated using experimental data. The process optimization study for the gasification of PKS utilizing the coal bottom ash as a catalyst is conducted in the continuous advanced fluidized bed technology pilot-scale gasification plant to determine the optimum conditions to produce maximum H2 and syngas composition. The optimum conditions for maximum H2 and syngas composition are a temperature of 625 °C, PKS particle size of 1–2 mm, and coal bottom ash to PKS percentage of 7.5 %. The optimum operating condition results are then validated in the pilot-scale gasification system. Steady-state simulation of the pilot scale biomass gasification plant is then developed using Aspen Plus® and validated using the experimental data.

Bottom ash (BA) is the dominant residue derived from the incineration of municipal solid waste or refuse-derived fuel (RDF). Costs for the disposal of the material chiefly depend on the leachability of salts and trace metals which may be cut by ageing the BA for several months to promote carbonation via uptake of carbon dioxide (CO2). Enhanced exposure to CO2 sources has been referred to as accelerated carbonation. Here we report on the successful implementation of the accelerated carbonation of BA in a continuously fed full-scale rotating drum reactor. The reactor was operated with the fine fraction (

The use of by-products as raw materials in the manufacturing of industrial products has risen in the last years because of environmental considerations. One example is the use of coal ashes from thermal-electrical plants in the production of geopolymer -- a green cement made by mixing aluminosilicate with alkaline activator. In this study, fly and bottom ashes from a thermal-electrical unit were used as sources of aluminosilicate in the synthesis of geopolymers. A mixture of sodium hydroxide (10 mol/L) and sodium silicate (SiO2/Na2O ratio of 2.2) was used as the alkaline activator. The type (fly or bottom ash) and content of the ash were the variables in the synthesis. The ashes were characterized by X-ray fluorescence (XRF), X-ray diffraction (DRX), particle size distribution (PSD), specific surface area (BET), and thermal analysis (DTA/TGA). The ash-based geopolymer samples were measured to obtain their compressive strength after curing. The evolution of the geopolymerization process was also assessed based on final alkali concentration measurements. The results show that it is possible to obtain geopolymers using coal ashes as raw materials with high solid content. The compressive strength for the bottom ash geopolymer after 90 days of curing is 35 MPa. The low concentration of unreacted alkalis after curing (1.5× 10-3 – 3.5 × 10-3 M) corresponds to high efficiency of the geopolymerization reaction.

The co-gasification of refuse derived fuel (RDF) and biomass is a promising technology for environmentally friendly municipal solid waste (MSW) utilization. Herein, we investigated the co-gasification of RDF and straw mixtures. The development of syngas suggested that higher temperature and equivalence ratio (ER) values promote syngas yield during gasification and co-gasification. Temperature plays a positive key role in gas yield and carbon conversion efficiency once the ER is higher than 0.3 during co-gasification. Except for an ER of 0.3, synergistic enhancements in carbon conversion efficiency, gas yield, and cold gas efficiency were observed for co-gasification. The positive synergistic effects of co-gasification mainly appeared in lower ER (0.1−0.2) and higher temperatures (800−900 °C); however, the negative synergistic effects more tend to appear in higher ER (0.3−0.4). From the development of bottom ash in co-gasification, at higher temperature and ER values, potassium in the bottom ash was favored to stay in sulfur-containing compounds; whereas at lower temperature and ER values, potassium preferred to exist in potassium chloride. A higher calcium content more easily enriched in small particles that were integrated into aluminosilicate led to the formation of sticking ash particles, which could promote significant melting agglomeration. However, these melting agglomerations could be suppressed by adding straw into the RDF. These results provide a feasible method for the resource utilization of MSW.

To investigate the reasons of high carbon content in bottom ash (BA) and guide the suitable utilization of residual carbon, the physicochemical properties of BA which was obtained from an industrial circulating fluidized bed coal gasifier were primarily studied via Raman spectrometer, N2 adsorption test and thermogravimetric analysis and compared with raw coal (RC) and fly ash (FA). BA has the lowest combustion reactivity than RC and FA, which is attribute to high degree of carbon deactivation, limited specific surface area, low catalysis elements contents and high ash content. In this study, the carbon content of BA first increases and then decreases with increasing BA particle size and the peak value appears at about 2 mm. The degree of carbon deactivation increases and specific surface area decreases with increasing BA particle size. Furthermore, it was found that some BA particles were covered with compact shell, which probably hindered the adequate conversion of inside carbon. The formation of shell was presumably owing to the re-attachment of volatile matter to the char matrix and the migration of coal ash, based on the results of Ramen spectra and SEM.

To recycle incineration bottom ash as a raw material in cement production, it is important to reduce the chlorides in the ash. Due to Friedel’s salt, washing only is insufficient to remove the chlorides. However, limited research has examined the mechanism of Friedel’s salt formation in ash. In particular, the effect of heating in an incinerator has not been reported. In this study, we investigated the formation of Friedel’s salt using reagents. Friedel’s salt was sufficiently formed upon heating at 1350 °C for 24 h and curing for 30 days. Higher temperatures than actual incineration conditions were required to produce pure Friedel’s salt, but a small amount of chlorine was also fixed in samples closer to actual incineration conditions. XRD and TG/DTA showed that the fixed chlorine most likely contained Friedel’s salt analogues. Washing experiments conducted to understand the leachability of chlorides from samples showed that 20–69% of the fixed chlorine did not dissolve during washing. The leaching behavior of the coexisting materials suggested that some of the fixed chlorine was present not in the form of Ca4Al2O6Cl2·10H2O but in chlorides or mixtures of chlorides with Ca and Cl bound at ratios of 1:1–2, which are more easily dissolved.

Phosphorous is one of the essential elements for living-forms on the Earth; however, the excessive presence of phosphate in the environment causes water pollution. Several methods have been developed and applied for phosphate removal in wastewater and adsorption is considered as a low-cost, simple, and stable technology for wastewater with low phosphate concentration. Although several mesoporous materials have been used as adsorbents, there has not been any report on the utilization of rice husk ash as support for iron oxide/hydroxide growth toward phosphate removal. In this study, flower-like iron(III) oxide/hydroxide on activated rice husk ash support (Fe-ARHA) was synthesized and applied as a novel material for phosphate removal in aqueous solution. ARHA was prepared by the chemical corrosion method with HF acid using bottom ash of a brick kiln using rice husk as fuel. Flower-like iron oxide/hydroxide was then grown on the surface of ARHA by precipitation of iron(III) sulfate using urea solution. The materials were then characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy to explore their properties. The mechanism for the formation and growth of flower-like iron oxide/hydroxide on the ARHA surface was proposed. In batch phosphate removal test, Fe-ARHA with Fe/ARHA ratio of 5 : 3 showed the highest adsorption capacity of 37.8 mg/g, which could be due to the interaction between iron oxide/hydroxide and ARHA support. This flower-like morphology and the interaction let more iron oxide/hydroxide surface be exposed to the water environment and effectively serve as adsorption sites for phosphate removal. These results prove the potential for the utilization of waste rice husk ash and iron oxide for water and advanced wastewater treatment applications.

This research has produced foamed glass-ceramics from coal fired power station furnace bottom ash (FBA) and soda-lime-silica glass. The as-received FBA was wet milled with different additions of glass. The resultant slurry was dried and formed into a powder. The powder was pressed and sintered at a range of temperatures with additions of a fluxing agent (sodium tetraborate decahydrate), a bubble stabilising additive (tri-sodium phosphate) and a bloating agent (calcium carbonate) and this produced foamed FBA-glass-ceramics. The effect of glass content and sintering temperature on the properties of the sintered ceramic foams are reported. A range of potential applications including thermal insulation and biological filters for water and wastewater treatment are discussed. The research demonstrates that it is possible to engineer the properties of FBA derived glass-ceramic foams by careful control of the composition and processing conditions in order to transform a problematic waste into commercially interesting materials.

In this work, coal bottom ash was modified by alkaline fusion route in order to improve its pore properties and make it a potential adsorbent to remove crystal violet dye from aqueous medium. The solids were characterized and posteriorly subjected to kinetic, isotherm, and thermodynamic studies, as well as regenerated and reused for five adsorption tests. The alkaline fusion step resulted in the amorphization of material and generation of high surface area (102 m 2 g −1) and pore volume (0.180 cm 3 g−1), resulting in superior performance compared to the raw material. Kinetic and equilibrium studies showed that the adsorption process was better adjusted by the pseudo-second order and Langmuir models, respectively. The maximum adsorption capacity at equilibrium was 177. 37 mg g−1, with the adsorptive step occurring spontaneously and endothermically. The adsorbent maintained notable levels of dye removal after five consecutive cycles of thermal regeneration and reuse. Besides, the adsorbent was able to remove 64% of the colour of simulated industrial wastewater. Therefore, the alkaline fusion step proved to be a route capable of transforming the coal bottom ash into an adsorbent with improved textural and adsorptive properties.

Bottom ash (abu dasar) adalah sisa pembakaran batu bara di Indonesia di kategorikan sebagai limbah (B3). Kandungan logam berat dalam limbah B3 menyebabkan pencemaran lingkungan. Bottom ash melimpah dan kurang dimanfaakan. Oleh karena itu berbagai inovasi dilakukan peneliti agar penggunaan kontruksi beton layak digunakan terhadap pengaruh hujan asam serta pengelolaan bottom ash sebagai material konstruksi beton. Pada penelitian ini persentase substitusi bottom ash agregat halus sebanyak 0%, 25%, 35% dapat digunakan untuk campuran beton dengan perendaman asam sulfat pH-4. Dengan benda uji yang digunakan berukuran 15 cm x 30 cm dan 60 cm x 15 cm x 15 cm sebanyak 45 sampel, menggunakan metode American Concrete Institute (ACI). Pengujian tersebut berupa pengujian kuat tekan. kuat tarik belah dan kuat lentur beton dengan mutu rencana sebesar 30 MPa. Pada umur 28 hari didapatkan nilai kuat tekan sebesar 32,727 Mpa, 33,859 Mpa, 36,782 Mpa. Beton dengan substitusi bottom ash sebagai agregat halus dengan variasi 0%, 25% dan 35% mengalami peningkatan kekuatan seiring bertambahnya persentase substitusi bottom ash dimana semakin tinggi persentase substitusi bottom ash maka kekuatan beton semakin tinggi, sehingga dapat dikatakan bahwa persentase substitusi bottom ash berbanding lurus dengan kekuatan beton.

The volatilization of heavy metals in oil sludge (OS) restricts the development of OS incineration. In order to explore the effect of CaO on the migration characteristics of heavy metals during OS incineration, incineration experiments of OS with and without CaO were carried out respectively in a horizontal tube furnace at the temperature ranging from 800 °C to 1000 °C. The total amount, speciation fractions, and leachability of Cr, Cu and Zn in OS and bottom ash were investigated and presented in this work. The results showed that the total amount of Cr, Cu, and Zn in the bottom ash decreased with the increasing of experimental temperature. CaO could solidify the heavy metals in the bottom ash with an order of Cu, Cr, and Zn from strong to weak. In the presence of CaO additive, the exchangeable and acid-soluble fractions of Cu and Zn in bottom ash were significantly reduced. Moreover, the leaching levels of Cr, Cu and Zn in bottom ash were also obviously lowered. The results will supply essential data and theoretical support for the innocuous treatment of heavy metals in the bottom ash of OS incineration.

Nowadays the disposal of bottom ash and fly ash are the major problem in industries. These wastes become pollutants to the environment and induce hazardous effects to human beings. So these wastes (ash) are replaced or reclaimed to other economical applications. This paper mainly deals with thermal power plant bottom ash. Their property includes volume of expansion, compressive strength, cohesiveness and refractoriness. The initial process includes that ash is mixed with silica sand by using binders to prepare the mould. Later the preparation of mould is to be introduced which undergoes several test like sieve test, sand hardness test. By using mould the casting is prepared and the physical property of the finished casting is tested under SEM, XRD. Finally the castings are produced using moulding sand mixed with 20 wt% of bottom ash and different binders (bentonite and sodium silicate binder). It was found that castings prepared by sodium silicate binder have high impact strength and hardness value compared with bentonite binder.

Geopolymer products are formed by mixing of raw materials in the presence of activator solution of sodium hydroxide. The raw materials such as fly ash & bottom ash are by-products of power plants and granulated blast furnace slag (GBFS) is a by product of steel production units. Environment friendly disposal of these by products are a challenging problem because of the cost involved. This paper deals with the development of eco-friendly geopolymer products by using these industrial by- products. For effective use of these products it is important to know how the composition, concentration of activator solution and exposure to adverse environment affects the compressive strength of the product. In order to develop mathematical models to predict the effects of proportion of different raw materials, exposure time in various atmospheres (such as air, acetic acid, magnesium sulphate, sodium sulphate and sodium chloride) and concentration of activator solution on compressive strength of geopolymers, the statistical technique of Central Composite Design is chosen. The maximum compressive strengths predicted by the models for the cases, when samples are exposed to 1%, 2%, 3% NaCl solution are 12.79Mpa, 10.91 MPa and 11.38 MPa respectively, at the end of 140 days. Compared to that, the predicted compressive strength of the sample exposed to airis 14.33 MPa at the end of 140 days. The other important observation is that, in both the cases, the compressive strengths are increasing with the length of exposure time. This assumes importance as NaCl solution is highly corrosive. The peak values in both the cases are yet to reach. These are the most significant results that are obtained in this study.

Phosphate in freshwater possesses significant effects on both quality of water and human health. Hence, many treatment methods have been used to remove phosphate from water/wastewaters, such as biological and electrochemical methods. Recent researches demonstrated that adsorption approaches are convenient solutions for water/wastewater remediation from phosphate. Thus, the present study employs industrial by-products (bottom ash (BA)), as a cost-effective and eco-friendly alternative, to remediate water from phosphate in the presence of competitor ions (humic acid). This study was initiated by characterising the chemical and physical properties of the BA, sample, then Central Composite Design (CCD) was utilised to design the required batch experiments and to model the influence of solution temperature (ST), humic acid concentration (HAC), pH of the solution (PoS) and doses of adsorbent (DoA) on the performance of the BA. The Langmuir model was utilised to assess the adsorption process. The outcomes of this study evidenced that the BA removed 83.8% of 5.0 mg/l of phosphates at ST, HAC, PoS and DoA 35 °C, 20 mg/L, 5 and 55 g/L, respectively. The isotherm study indicated a good affinity between BA and phosphate. Additionally, the developed model, using the CCD, reliably simulated the removal of phosphates using BA (R2 = 0.99).

Bottom ash generated by the combustion of cattle manure (BA-CCM) was investigated as an adsorbent for the removal of heavy metals such as Cd(II), Cu(II), Pb(II), and Ni(II) from aqueous solutions. When cattle manure was used as fuel, the thermal efficiency of the boiler was 88.7%, and the CO and CO2 concentrations in the exhaust gas were 2.3 ppm and 12.1%, respectively. The percentage of remaining solids was 31 wt.% after combustion at 900 °C. X-ray fluorescence analyses showed that the elemental composition of the BA-CCM was mainly CaO (43.3%), SiO2 (15.8%), CO2 (13.0%), and P2O5 (10.3%). The kinetic adsorption of Cd(II), Cu(II), Pb(II), and Ni(II) by BA-CCM reached equilibrium after 12 h, and the pseudo-second-order model fitted the experimental data well. The maximum amount of Cd(II), Cu(II), Pb(II), and Ni(II) adsorbed by the bottom ash was 5.4, 72.6, 88.2, and 24.6 mg/g, respectively. The equilibrium adsorption of metals onto BA-CCM was well-described by the Freundlich model. Thermodynamic analysis showed that the adsorption onto the bottom ash was endothermic and that the Gibbs free energy decreased as the temperature increased. The presence of cations such as Na+, Ca2+, and Al3+ was found to reduce the amount of metals adsorbed onto the BA-CCM, and Cd(II) adsorption was found to be more dependent on ionic strength than adsorption of Cu(II), Pb(II), and Ni(II). This study demonstrates the feasibility of producing heat energy by burning cattle manure and removing heavy metals from aqueous solutions using the generated bottom ash as an adsorbent.

Resource and environmental safety protocols of incineration residues were evaluated by analyzing the metal concentration, heavy metal elution, desalination behavior, and chlorine removal ratio owing to particle size differences between bottom ash (BA) and grate sifting deposition ash (GA). In the total content test, Cl, Zn, and Cr in the incinerator BA exceeded the cement acceptance standard (Cl: 1000 mg/kg; Zn: 1700 mg/kg, and Cr: 170 mg/kg) at almost all of the particle sizes, while Au, Ag, Pd, and Zn had high contents in the GA. When using BA as a construction material, heavy metal elution values and contents are restricted as per the product quality standards based on the Japanese soil pollution control law. Lead within the BA and GA exceeded the standard values for most particle sizes. We predicted that there would be a limit on the elution of K by only washing with water. The removal ratio of total chlorine by particle size was approximately 20–70%, where the effect of the particle size on the removal ratio was small, suggesting that the elution of chlorine was complete in approximately 6 hours. These results contribute to information on the recycling of BA and GA.

In this paper, fly ash and bottom ash produced from the gasification of pine sawdust in a fixed bed gasifier were compared in details to investigate the ash forming characteristics and fouling/slagging behaviours. For this purpose, a detailed comparison of fly ash and bottom ash was carried out. It was found that compared with the ash composition of raw pine sawdust, gasification ashes showed higher contents of alkali metals (K, Na) and Cl. S. Both the bottom ash and fly ash were strongly crystalline, with calcite as the prevailing phase. The ash fusion temperatures for fly ash were higher than those for bottom ash, while the interval between the deformation temperature and softening temperature for bottom ash (88 °C) was larger than that for fly ash (73 °C), suggesting the higher fouling/slagging propensity of bottom ash. The Si/(Ca + Mg) ratio for the bottom ash (1.10) was lower than that for fly ash (1.29), further indicating the low melting of bottom ash. From a mineralogical standpoint, the major difference between fly ash and bottom ash was that the former possessed a higher content of potassium-rich salts that facilitated the adhesion of small particles to larger particles during biomass gasification process.

As indispensable strategic materials for high-tech industries, rare earth elements and yttrium (REY) have become particularly important in recent years, raising the demand of developing new approaches for reclamation of REY from REY-rich materials such as coal combustion products (CCPs). In this study, five coal-fired power plants (CFPPs) in Guizhou of southwest China were selected for investigating REY concentrations of solid samples, atmospheric emissions, and recovery potentials. REY concentrations of feed fuels are higher in this study (147.2–468.6 mg/kg) than what have been reported previously for coals in China and the world. REY atmospheric emissions are extremely low (38.70–180.11 mg REY/t coal). REY are enriched in bottom ash and fly ash, with average of 658 ± 296 mg/kg and maximum of 1257 mg/kg from the five CFPPs. Relative enrichment factors (REF) of REY in bottom ash and fly ash compared with the feed fuel are 0.86–1.02 and 0.91–1.04, respectively. REY concentrations in desulfurized gypsum are very low (6–17 mg/kg), and that is mostly inherited from limestone. Critical REY (Nd, Eu, Tb, Dy, Y, and Er) in bottom/fly ash account for 34%–39% of the total REY and the outlook coefficients (Coutl) are in the range of 0.89–1.11. This study indicates a promising prospect to reclaim REY from REY-rich CCPs (bottom and fly ash) in CFPPs in Guizhou, especially in the central-north Guizhou, although such practices require further technology advancement.

Bottom ash samples were collected during four seasons from the largest lignite-fired power plant of Greece, named Agios Dimitrios. Dry sieving and particle size analysis were performed for all samples. Coarse fractions were initially examined by a stereo-microscope. Four fractions (>1.25, 0.63–1.25, 0.18–0.63, 1.25 mm) of all samples, indicating a problematic combustion within the chambers and a potential of reburning these coarse material in a waste to energy application.

The impact of holding time and particle size of bottom ash on the mechanical properties of polypropylene composites has been investigated. The size of the used particle were 200-250, 250-300, and 300-350 mesh with the holding time variations were 0, 30, 60, and 90 minutes. The initial process of the bottom ash was cleaned with fresh and warm water, then drained and dried at a 120°C for 3 hours. In the making process of composites, the bottom ash was mixed into the polypropylene matrix by stirring at a speed of 20 rpm for 30 minutes. The results of this study showed that the highest composite strength values were obtained in composites with the particle size of 250-300 mesh. Tensile strength increased about 45% for composites without providing holding time (0 minutes), while the bending strength value increased significantly to 103% obtained on composites given a holding time of 30 minutes. The results of this study will be used as a basis for further research and hopes of getting better alternative engineering materials in the form of composites.