Types Of Ash Research Articles

Effect of TiO2 and fly ash on photocatalytic NOx abatement of engineered cementitious composites

Titanium dioxide (TiO2) nanoparticles have been incorporated in cementitious composites to achieve photocatalytic (PC) functions such as self-cleaning and air purifying functions. This study experimentally investigates the effect of TiO2 nanoparticles and fly ash on the nitrogen oxides (NOx) abatement rate and efficiency of Engineered Cementitious Composites (ECC) that has retained strain-hardening properties and tensile ductility. Emphasis is placed on understanding the fundamental mechanisms through research on the microstructures and chemical environment of the composite material. A first-order chemical reaction model is applied to analyze the PC reaction rate and residual NOx concentration. Test results indicate that the PC reaction rate and efficiency increase with the TiO2 content from 0 to 5%, and the fly ash to cement ratio from 0 to 2.2. Using the low-calcium fly ash further increases the PC reaction rate and efficiency. The microstructure change originated from different fly ash contents and types are closely related to PC efficiency changes. This study advances the fundamental knowledge for engineering the cementitious composites to achieve the optimal PC functions.

Evaluation and Analysis of Lightweight Concrete (LWC) Manufacturing and Applications

This paper presents the evaluation and analysis of LWC) manufacturing and applications. Clear comparisons of different LWC types according to the physical specifications and properties lead to accurate selection of concrete type depending on the conditions surrounding the buildings projects. The widely used of LWC in all over the world is approaching researchers to seriously consider finding new techniques to produce more resistant varieties nearby conditions of construction projects. The LWC types are more sustainable than burnt brick due to its providing high densities and better insulation. This work has been carried out the deep discussion and comparison between the properties of fly ash, AAC and CLC concrete types. The advantage of aerated lightweight concrete compared with traditional concrete is present in advance strength to weight ration, less thermal expansion coefficient and high insulation of sound. The classified of aerated lightweight concrete into foamed and autoclaved concrete has attention in the suggested mixture. By maintain the density as constant parameter, their load carrying capacity in compression, water absorption and thermal insulation are to be tabulated and concluded by their performance.

Strength Characteristics and Load-Deflection Behavior of Fly Ash Based Reinforced Concrete Beams

Fly ash is a residual material of energy production using coal, which has been found to have numerous advantages for use in concrete. Some of the advantage include improved workability, reduced permeability, increased ultimate strength, reduced bleeding, and better surface and reduced heat of hydration. Several types of fly ash are produced, depending on the coal and coal combustion process. It is a pozzolanic material and has been classified into two classes. Fly ash is one of the residues generated in combustion and comprises the fine particles that rise with the flue gases This paper focuses on the experimental investigation to study percentage replacement of fly ash for cement content in the concrete and deciding the water binder ration to achieve the intrinsic properties such as compressive strength, split tensile strength and flexural strength for a mix design by casting number of cubes, cylinders and prisms to ascertain that the strength characteristics and then to understand the load-deflection characteristics, model beams were cast and tested after 28 days of curing. A replacement of 30% of fly ash to the weight of the cement is optimum to achieve the required strength and ascertain that the durability properties can also adequately achieved.

Study on the mineral phase characteristics of various Indian biomass and coal fly ash for its use in masonry construction products

The productive utilization of the vast amount of industrial ash generated is of economic and environmental importance. The use of industrial ash in brick manufacturing gives the two-fold advantage of the reduced cost of fly ash bricks as well as efficient disposal of industrial ash. However, due to variations in chemical characteristics in the various types of ashes originated from different sources, and production processes often lead to restricted use in lime based fly ash bricks. To overcome this, comprehensive characterization of different industrial ashes is necessary to clearly define the chemical characteristics that have influencing role on the lime based fly ash bricks. Considering this, XRD patterns, FT-IR spectra, Raman spectra, SEM images, and chemical reactivity method have been collectively used for comprehensive characterization of industrial ashes, including their mineralogy, particle morphology, and lime reactivity. A total of six different ashes have been characterized, including two biomass ash and three coal based ash from local industries, and one coal based ash from thermal power plant. The primary aim of the study is to assess the suitability of the proposed experimental programme to characterize local industrial ashes and to evaluate their potential to use them as raw material in masonry construction products. From the present study, it is revealed that by and large, local coal-based industrial ash can be utilized in lime based fly ash bricks based on their comprehensive characterization. The results obtained by characterization of industrial ash are expected to provide helpful insights to evaluate their potential to manufacture masonry construction products.

Elemental compositions and sizes of carbonaceous fly ash particles from atmospheric deposition collected at Cape Hedo, Okinawa, Japan: Implications for their long-range transportation and source region variation

Spheroidal carbonaceous particles (SCPs) are a type of carbonaceous fly ash resulting from high-temperature industrial fossil fuel combustion. In this study, we examined the fluxes, elemental compositions (18 elements including silicon, sulfur, and aluminum but not carbon) and sizes of dry-deposited SCPs in the atmosphere at Cape Hedo (the northernmost part of Okinawa Island) to assess the temporal variation. The study site at Cape Hedo is suitable for investigating atmospherically deposited SCPs, particularly for evaluating their long-range transportation, because Cape Hedo is situated in an outflow region of East Asian pollutants. High SCP fluxes mostly occurred in autumn and winter when air masses came from the Asian continent. Additionally, we determined the temporal variations in the elemental compositions and the sizes of the SCPs during four week-long sampling periods and these results suggest that the high SCP fluxes were due to the transportation of the particles from the Asian continent to the study site. The potential source regions of the particles during respective periods are very consistent with the backward air mass trajectories. Results of our study would imply that sources of the SCPs deposited in the area changed temporarily, and that coarse particulate-pollutants such as SCPs were transported from the eastern Asian continent to Okinawa Island during the periods under specific meteorological conditions. Our findings suggest that the examination of SCPs from atmospheric deposition can contribute to the assessment of atmospheric transportation, specifically for particulate pollutants in the atmospheric boundary layer.

Study of Proportional Variation of Geopolymer Concrete which Self Compacting Concrete

Portland cement production process which is the conventional concrete constituent materials always has an impact on producing carbon dioxide (CO2) which will damage the environment. To maintain the continuity of development, while maintaining the environment, Portland cement substitution can be made with more environmentally friendly materials, namely fly ash. The substitution of fly ash material in concrete is known as geopolymer concrete. Fly ash is one of the industrial waste materials that can be used as geopolymer material. Fly ash is mineral residue in fine grains produced from coal combustion which is mashed at power plant power plant [15]. Many cement factories have used fly ash as mixture in cement, namely Portland Pozzolan Cement. Because fly ash contains SiO2, Al2O3, P2O3, and Fe2O3 which are quite high, so fly ash is considered capable of replacing cement completely.This study aims to obtain geopolymer concrete which has the best workability so that it is easy to work on (Workable Geopolymer Concrete / Self Compacting Geopolymer Concrete) and obtain the basic characteristics of geopolymer concrete material in the form of good workability and compressive strength. In this study, geopolymer concrete is composed of coarse aggregate, fine aggregate, fly ash type F, and activators in the form of NaOH and Na2SiO3 Be52. In making geopolymer concrete, additional ingredients such as superplastizer are added to increase the workability of geopolymer concrete. From this research, the results of concrete compressive strength above fc' 25 MPa and horizontal slump values reached 60 to 80 centimeters.

Contents and associations of rare earth elements and yttrium in biomass ashes

The contents and associations of 14 rare earth elements and Y (REY), as well as the phase-mineral and chemical composition of biomass ashes (BAs) from eight biomass varieties were studied. An elucidation of the REY contents in BAs was conducted and a comparison with coal ashes (CAs) was performed. The correlations and associations of REY with major and minor elements, and different mineral classes in BAs are given. It was found that REY commonly have about one order of magnitude lower bulk concentrations in BA than those in CA. The distribution of REY in BAs is strongly dependent on the plant species and their source, and the different inorganic ash types. The individual REY show numerous strong and significant positive correlations; however, three major associations can be divided according to these correlations, namely: (1) light Ce, La, Nd, and Pr with Al2O3 + Fe2O3 + TiO2, Al, phosphates, and Ti; (2) medium Y with carbonates, oxides and hydroxides, and K; and (3) light Sm, medium Dy, Eu, Gd and Tb, and heavy Er, Ho, Lu, Tm and Yb with Si and silicates. BA is a less prospective resource for a recovery of REY than CA according to their bulk concentrations; however, BAs are abundant in water-soluble components and their solutions may be used for REY recovery. The data also indicate that the low REY concentrations in BA would not have potential environmental and health concerns excluding their occurrence in mobile forms and in some radioactive silicate and phosphate minerals.

Ammonia in Fly Ashes from Flue Gas Denitrification Process and its Impact on the Properties of Cement Composites

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of fly ash: Silica fly ash from flue gas denitrification and ash from a traditional boiler without the flue gas denitrification process. The scope of comparative studies included physicochemical and structural features of ashes, as well as slurries and mortars with the addition of ashes. Fly ash from denitrification, whose ammonia content at the time of sampling was 75 mg/kg at the maximum, was examined. Our own research has shown that fly ash from flue gas denitrification is characterized by a higher value of losses on ignition and ammonia content in comparison to ashes without denitrification. It was shown that the ammonia content in the analyzed range does not limit the use of fly ash as an additive to cement and concrete.

Life cycle assessment of the reuse of fly ash from biomass combustion as secondary cementitious material in cement products

In this study, we performed a life cycle assessment of the reuse of biomass fly ash as secondary cementitious material in cement mortars as alternative to a reference landfill scenario of the ash. Since biomass ash does contain enhanced levels of elements that are of potential concern for the environment or human exposure, the performed Life Cycle Assessment (LCA), in addition to CO2 savings, takes into account the impact on all non-toxic categories and human toxicity/carcinogenicity during service and second life stages. Results showed that utilization of biomass ash in cement is preferable over landfill for all the non-toxic categories at both cement replacements rates of 20 and 40 wt%. In detail, the reduction of CO2-eq. was found to be between 11 and 26% when biomass ash was blended with cement instead of being landfilled. The hydraulic activity of biomass ashes was found to be a critical parameter in this scenario, as it had impacts on the global warming potential (and all other investigated non-toxic categories), and it is therefore crucial to consider the uncertainty related to this aspect in LCA studies. Cement containing biomass ash performed better, on average, when compared with the reference landfill scenario regarding the impact to human toxicity (carcinogenic) category. Contrary, only the utilization in cement for one particular ash type (from paper sludge combustion) showed a better performance than the reference scenario for the ecotoxicity (ET) category. The impact to human toxicity carcinogenic (HTc) and ecotoxicity (ET) was mainly dominated by the leaching of Cr from landfilling of pure biomass fly ash (reference scenario) and the leaching of Ba, Cu, Cr (VI) and Zn from the second life stage of cement products (i.e., reuse of the crushed cement after service life in road base applications). However, this impact was acceptable when emissions are compared to existing EU landfill directive and regulations on the reuse of secondary materials in construction works. The novel LCA approach performed in this study, which includes impacts of leached contaminants during both the service and second life phase of cement, has shown that the reuse of biomass ash as secondary cementitious materials has a beneficial effect on the majority of the impact categories, with no unacceptable leaching risks.

Microbial induced solidification and stabilization of municipal solid waste incineration fly ash with high alkalinity and heavy metal toxicity.

This paper presents an experimental study on the applicability of microbial induced carbonate precipitation (MICP) to treat municipal solid waste incineration (MSWI) fly ash with high alkalinity and heavy metal toxicity. The experiments were carried out on fly ashes A and B produced from incineration processes of mechanical grate furnace and circulating fluidized bed, respectively. The results showed that both types of fly ashes contained high CaO content, which could supply sufficient endogenous Ca for MICP treatment. Moreover, S. pasteurii can survive from high alkalinity and heavy metal toxicity of fly ash solution. Further, the unconfined compressive strength (UCS) of MICP treated fly ashes A and B reached 0.385MPa and 0.709 MPa, respectively. The MICP treatment also resulted in a reduction in the leaching toxicity of heavy metals, especially for Cu, Pb and Hg. MICP had a higher solidification and stabilization effect on fly ash B, which has finer particle size and higher Ca content. These findings shone a light on the possibility of using MICP technique as a suitable and efficient tool to treat the MSWI fly ash.

PEMBERIAN ABU SEKAM PADI DAN JERAMI PADI UNTUK PERTUMBUHAN SERTA SERAPAN TANAMAN JAGUNG MANIS (Zea Mays L.) PADA TANAH ULTISOL DI KECAMATAN RANTAU SELATAN

Provision of Rice Husk Ash and Rice Straw for Growth of Sweet Corn (Zea Mays L) in Ultisol Land in Rantau Selatan District Labuhan Batu District aims to determine the effect of various types of rice husk ash and rice straw for growth and nutrient uptake of Sweet Corn experimental methods. The method used in this study was compiled in a factorial randomized block design consisting of 2 factors with 3 replications. Treatment I: Giving rice husk ash (M) with 4 dose levels (g / 5 kg BTKO), namely: M0 (0), M1 (10 ), M2 (20) and M3 (30) and Treatment II: Giving rice straw (K) compost with 4 dose levels (g / 5 kg BTKO), namely: K0 (0), K1 (25), K2 (50), K3 (75). The data obtained were statistically analyzed based on analysis of variance on each observed variable that was measured and tested further for real treatment using the Duncan Multiple Range Test (DMRT) at the 5% level. The parameters measured consist of. Plant height (cm), Plant Dry Weight, Plant U uptake, Plant U Uptake. The results of this study indicate that the administration of rice straw compost has a significant effect in increasing plant height, plant dry weight, N uptake and P uptake while rice husk ash has a significant effect in increasing plant N uptake but has no significant effect in increasing plant height, plant dry weight and P uptake of plants. Keywords: husk ash, rice straw, growth, nutrient uptake, corn, Rantau selatan

Strength Development and Thermogravimetric Investigation of High-Volume Fly Ash Binders.

To address sustainability issues by facilitating the use of high-volume fly ash (HVFA) concrete in industry, this paper investigates the early age hydration properties of HVFA binders in concrete and the correlation between hydration properties and compressive strengths of the cement pastes. A new method of calculating the chemically bound water of HVFA binders was used and validated. Fly ash (FA) types used in this study were sourced from Indonesia and Australia for comparison. The water to binder (w/b) ratio was 0.4 and FA replacement levels were 40%, 50% and 60% by weight. Isothermal calorimetry tests were conducted to study the heat of hydration which was further converted to the adiabatic temperature rise. Thermo-gravimetric analysis (TGA) was employed to explore the chemically bound water (WB) of the binders. The results showed that Australian FA pastes had higher heat of hydration, adiabatic temperature rise, WB and compressive strength compared to Indonesian FA pastes. The new method of calculating chemically bound water can be successfully applied to HVFA binders. Linear correlation could be found between the WB and compressive strength.

Recent Advancements in Geopolymer Concrete using Class-F and Class-C Fly Ash

In recent decades, to depreciate usage of ordinary Portland cement(OPC) for the construction industry, enormous research work is going on high rich Al-Si waste materials as source material for producing Geopolymer concrete(GPC). In this paper, a review is done in three ways namely A) To study the short term and long term characteristics of various types of fly ash based Geopolymer concrete(GPC) and B) Development of Hybrid Geopolymer concrete, by partial replacement of fly ash with high calcium materials like Cement, slag and . C) Field applications of Geopolymer concrete (GPC); The research papers published are thoroughly reviewed to identify the research gap . Keywords—Class-C Flyash (FA-C) ,Class-F Flyash (FA-F), Ground granulated blast furnace slag(GGBS), Alkaline

Influence of coal ash on CO2 gasification reactivity of corn stalk char

The effect of added coal ash on the gasification behavior of corn stalk char by using the thermalgravimetric analysis and a lab-scale horizontal fixed bed furnace was investigated. For comparison, synthetic ash with different chemical composition was used for studying the effect of difference ash composition on promoting/inhibiting the gasification reactivity. The results show that the slagging-control preferred coal ash additive has a negative impact on the gasification performance. Interestingly, a relatively less slagging-control preferred coal ash additive has a beneficial impact on promoting the gasification performance under low gasification temperature. This could be due to the difference composition between the two coal ash additives, where the former coal ash type has much lower content in the calcium and iron. In addition, the findings in the synthetic ash suggest that iron can have a better performance in promoting gasification than calcium/magnesium. Two types of coal ash show an inhibiting effect under higher temperature due to temperature might be the dominant factor and the restraining effect of additive. These observations are also supported by the evolution of char structure by using the Raman spectroscopy. Further, the modified random pore model can correlate well with the gasification kinetics data.

Kinetic study on elemental mercury release from fly ashes and hydrated fly ash cement pastes.

The kinetics of elemental mercury (Hg0) release from fly ashes and hydrated fly ash cement pastes was investigated using a homemade Hg measurement system. Three types of fly ash (FA) and ordinary Portland cement (OPC) were used to prepare cement pastes. After standard curing for 28 days, the hydrated cement paste (HCP) was ground into a fine powder for Hg emission measurements. Detectable Hg0 was found released from both fly ashes and hydrated fly ash cement pastes. The results show that elevated temperatures and evaporation of the capillary pore water in wet HCP samples accelerate Hg0 release. Both desorption of Hg0 from the particle surface of HCP powder and migration of Hg0 from the inner pores contribute to Hg0 release. The kinetic calculation indicates that the hydration products of hydrated fly ash cement have little immobilization effect on Hg0, which is mainly physically encapsulated in the HCP particles by hydration products.

Synthesis of Geopolymer from Blends of Tropical Biomass Ashes

Thermal conversion of biomass to produce energy inevitably generates ash as residual matter. Therefore, sustainable utilization of biomass should also consider reuse measures for the ash. This research examines the conversion of locally available biomass ashes in Indonesia into geopolymer. This is an environmentally more benign alkali-aluminosilicate alternative to the ordinary Portland cement produced by low-temperature reactions between aluminosilicates and concentrated alkali solution. Biomass ash sources in this study are corn stover, coconut shell, and sugarcane bagasse. Biomass ash blends are prepared according to a ternary simplex centroid mixture experiment design. These blends are reacted with activator solutions containing NaOH and Na-silicate and blended with sand aggregate to produce geopolymer mortar specimens. Early compressive strengths of geopolymer mortars range from 7.2 to 10.4 MPa, which surpasses the SNI 15-2049-2004 national standard for Portland cement with low heat of hydration. Statistical analysis of the experimental data indicates that the early strength as a function of biomass ash blend formulation is represented by a quadratic mixture model. Bagasse ash produces the highest strength. The quadratic terms consist of bagasse-corn and bagasse-coconut antagonistic blending terms. Morphology of the geopolymer mortar fracture surface indicates good bonding with the sand aggregate. Extensive acicular crystal growth within the amorphous geopolymer gel phase is observed in lower-strength formulations, which points to the formation of zeolite-like phase in the geopolymerization process. While the correlation of biomass ash type to the structure of the resulting geopolymer is yet to be established, this work has clearly identified the technical feasibility of producing geopolymer with satisfactory strength from tropical biomass ashes.

Optimization and Development of High-Strength High-Volume Fly Ash Concrete Mixes

Cement is the most abundantly used ingredient in the production of concrete due to which its production and use has increased manifold. To reduce the carbon footprint left by the cement production, fly ash is used as cement replacement in concrete. Past research studies suggest that the fly ash replacement can be upto 40% beyond which there will be drastic reduction of strength. In the present study, high strength concrete mix of 70 grade is developed with high volume fly ash of 70% as cement replacement. Silica fume of 10% and hydraulic lime of 30% are used as additives in the development of M70 grade high-strength high-volume fly ash concrete. In the present paper, three types of fly ashes are considered for the study of which one which is ultrafine is chosen based on the pozzolanic index and strength activity index. Excess lime needed for various percentage of fly ashes is evaluated based on the empirical equationsgiven by the Dunstan Jr andZayed.

Early hydration calorimetric study of the sewage sludge incinerated waste streams Portland cement-based binders: technological implications

The research study forms a part of the “Management of municipal water waste treatment plants potential by-products of sewage sludge ash type, as active or non-active additions to Portland cement-based binders” project’s outcomes (H2020-MSCA-IF-2016-746830). Based on the applied techniques characteristics (non-isothermal and non-adiabatic differential micro-calorimeter, SEM/EDS and XRF analysis), this study comprises the very first stage for a sustainable conversion of each of the considered 190114 and 190107* waste streams into a value-added by-product for specific constructive applications. Provided technical requirements regarding the designed cementitious products handling and suggested industrial application are focused on the early performance of the tested for quality and consistency, pastes, mortars and concretes. In detail, the obtained physical–chemical parameters show substantial differences of the original waste streams regarding their technological origin, seasonability and geographical localisation. Consequently, the calorimetric curves exhibit diverse early chemistry of the produced cements, showing the considerable variations in mineral nature (siliceous, aluminous) or hydraulic factor contents (reactive silica, SiO2r−, and reactive alumina, Al2O3r−) of the observed pozzolanic activities. Setting retarding phenomenon and shrinkage reducing effects are also carefully discussed. All the calorimetric and pozzolanic activity related data is contrasted with two other reference materials, fly ash and granulated blast furnace slag, standard behaviour.

Physicochemical and mineralogical characterization of biomass ash from different power plants in the Upper Rhine Region

Bottom and fly ash samples from six biomass power plants with different power scales and various flue gas treatment strategies were collected and analyzed in regard to their mineralogical composition, and their bulk major and trace element contents, all of which are of concern for regulations on biomass ash for further utilization. Furthermore, individual ash particles were investigated by scanning electron microscopy to characterize their physicochemical microstructures.Thermal behavior of wood-pellet ash, i.e. decomposition processes and mineral transformations during combustion, was indicated by thermogravimetric analysis and X-ray diffraction.Results reveal extensive variation of physicochemical features across the different ash types: wood-chip fly ash from electrostatic precipitators mainly consisted of water-soluble salts, whereas wood-chip fly ash from cyclones contained predominantly cenospheres (hollow spherical fly ash particles) and higher heavy metal concentrations. In addition, the fuel type and admixture had influences on ash compositions; some fuels like Miscanthus straw require a liming agent such as calcium hydroxide to be admixed to prevent fouling, which is then predominantly found in the ash. Furthermore, boiler size had an influence on fly ash composition. Cadmium concentrations were elevated in some fly ash samples at levels of concern for further utilization, whereas concentrations of troublesome Cr(VI) were below the detection limit for all investigated ash samples. Other contaminating elements such as Ni, Pb and Zn were variable but below limit values.Results clearly show that the nature of biomass ash calls for careful analyses prior to further application as, e.g., cement clinker replacement material.

Dark fermentative hydrogen production from food waste: Effect of biomass ash supplementation

This work aimed to investigate the effects of supplementing two distinct types of ash, namely fly ash (FA) and bottom ash (BA) on the dark fermentation (DF) process of food waste (FW) for H2 production. Both types of biomass combustion ash (BCA) were collected in an industrial bubbling fluidized bed combustor, using residual forest biomass as fuel. Results indicated that adding BCA at different doses of 1, 2 and 4 g/L could effectively enhance H2 generation when compared to the control test without BCA addition. This stimulatory effect was attributed to the crucial role of metal elements released from BCA such as sodium, potassium, calcium, magnesium, and iron in the provision of buffering capacity and inorganic nutrients for the functioning of hydrogen-forming bacteria. The highest H2 yield of 169 mL per g of volatile solids (VS) were obtained by adding only a small amount of BA (1 g/L) to the reactive system, representing a significant increment of 1070% compared to the control reactor. Furthermore, a significant decrease in the bacterial lag phase time from 26 h to 2.7 h, as well as about a 12-fold increase in the energy recovery as H2 gas was observed at BA dosage of 1 g/L in comparison with the control reactor. Overall, this study suggested that a proper addition of BCA could promote the DF process of FW and enhance biohydrogen production.