Ratio Of Bottom Ash Research Articles

Phase evolution, microstructure and properties of glass-ceramics derived from municipal solid waste incineration bottom ash and molybdenum tailings

Municipal solid waste (MSW) incineration bottom ash (BA) and molybdenum tailings (MTs) are bulk solid wastes that have low added value and is of a serious environmental concern. Hence, it is imperative to develop technology that potentially as convert these wastes into potential products that are safe to handle. In the present work, the goal is to synthesize glass-ceramics from BA and MTs without addition other supplement materials. The study attempts to assess the influences of raw material ratio and sintering temperature on the phase transformation, microstructure and properties of glass-ceramics. The synthesized product shows that diopside ferroan and anorthite were the dominant crystals, and the content of diopside ferroan and anorthite increased with an increase in the proportion of MTs. It was observed that the presence of Fe2O3 and TiO2 inside solid wastes promote nucleation facilitating growth of crystals. Diopside ferroan and anorthite distribute uniformly and are well interweaved, densifying the structure with favorable properties of glass-ceramics. At the optimal processing temperature the presence of Na2O and K2O in the raw materials act as fluxing agents that facilitate formation of liquid phase, that enhance diffusion and rate of crystallization. The optimal mass ratio of BA to MTs was 45:55 and the sintering temperature of 1000 °C, exhibited the best comprehensive properties of the glass ceramics. At the optimal conditions the flexural strength, Vickers hardness, bulk density and water absorption were observed to be 76.00 MPa, 5.77 GPa, 2.69 g/cm3 and 0.32 %, respectively. The leaching test proved stability of the glass ceramics, and hence can serve to be a potential way of utilizing the waste into a valuable product benefiting the environment and promoting sustainable growth.

Economical evaluation of reinforced concrete hospital construction cost using bottom ash and fly ash

The use of waste materials in nature (e.g. fly ash, bottom ash) in the construction phase of buildings is of great importance both in terms of environmental pollution and the construction cost of the structures. Therefore, in this study, the effects of bottom ash and fly ash on the construction cost of reinforced concrete (RC) hospital buildings are investigated by considering experimental tests and 3D nonlinear analyzes. During the experiments, four different concrete series are created and fly ash and bottom ash are added to replace 0–5 mm grain size aggregates in the concrete mixture at different ratios. The RC beams created according to four different concrete series are subjected to experimental tests. Afterward, it is determined that the most critical mixing ratio for RC beams subjected to experimental tests is selected as 75% bottom ash ratio and fly ash. For the purpose Ankara Bilkent City Hospital is selected for 3D nonlinear seismic analyses and the hospital structure is subjected to 10 various earthquake analyses. This study showed that there was a noticeable decrease in the construction cost when the costs of the hospital structure were compared as a result of the earthquake analysis. Another important point is that the use of bottom ash and fly ash is thought to contribute to savings in the energy to be used for the storage of wastes by causing less electrical energy use in cement production, less greenhouse gas emissions, natural raw material consumption and nature pollution.

Assessing effects of waste coal bottom ash on construction cost of reinforced concrete structures considering experimental data

In this study, it has been examined whether the bottom ash (BA) released to the nature as waste material from the thermal power plant can be used in reinforced concrete structures (RCS) and how much cost reduction will be caused in construction technology if BA is used in RCS. For this purpose, coal BA produced by Turkey-Zonguldak Cates power plant is mixed in different ratios into the concrete mixture of the beams. The different coal bottom ash ratio (BAR) is used instead of aggregate in the mixture. The beams created for 5 different BARs are subjected to tests and it is observed that the beam with the most critical bending is the beam with 75% coal BA. This BAR is applied to bearing elements of finite element model (FEM) and then current cost of the building and the construction cost used 75% coal BAR are compared with each other. It has been observed that when 75% coal BAR is used instead of aggregate in RCSs, there is a 40% reduction in construction costs. This result is of great importance both for the recycling of BA and for revealing that BA reduces construction costs.

The Effect of Bottom Ash Ball-Milling Time on Properties of Controlled Low-Strength Material Using Multi-Component Coal-Based Solid Wastes

As the conventional disposal method for industrial by-products and wastes, landfills can cause environmental pollution and huge economic costs. However, some secondary materials can be effectively used to develop novel underground filling materials. Controlled low-strength material (CLSM) is a highly flowable, controllable, and low-strength filling material. The rational use of coal industry by-products to prepare CLSM is significant in reducing environmental pollution and value-added disposal of solid waste. In this work, five different by-products of the coal industry (bottom ash (BA), fly ash, desulfurized gypsum, gasification slag, and coal gangue) and cement were used as mixtures to prepare multi-component coal industry solid waste-based CLSM. The microstructure and phase composition of the obtained samples were analyzed by scanning electron microscopy and X-ray diffraction. In addition, the particle size/fineness of samples was also measured. The changes in fresh and hardened properties of CLSM were studied using BA after ball milling for 20 min (BAI group) and 45 min (BAII group) that replaced fly ash with four mass ratios (10 wt%, 30 wt%, 50 wt%, and 70 wt%). The results showed that the CLSM mixtures satisfied the limits and requirements of the American Concrete Institute Committee 229 for CLSM. Improving the mass ratio of BA to fly ash and the ball-milling time of the BA significantly reduced the flowability and the bleeding of the CLSM; the flowability was still in the high flowability category, the lowest bleeding BAI70 (i.e., the content of BA in the BAI group was 70 wt%) and BAII70 (i.e., the content of BA in the BAII group was 70 wt%) decreased by 48% and 64%, respectively. Furthermore, the 3 d compressive strengths of BAI70 and BAII70 were increased by 48% and 93%, respectively, compared with the group without BA, which was significantly favorable, whereas the 28 d compressive strength did not change significantly. Moreover, the removability modulus of CLSM was calculated, which was greater than 1, indicating that CLSM was suitable for structural backfilling that requires a certain strength. This study provides a basis for the large-scale utilization of coal industry solid waste in the construction industry and underground coal mine filling.

Structural parts based on Municipal-Solid-Waste incineration ashes

We investigated a novel processing technique of municipal solid waste incineration (MSWI) ashes. By using two thermodynamic driving forces – a strong alkaline activator and a compaction pressure, the otherwise relatively nonreactive MSWI ashes could form strong solids, with relatively high flexural and compressive strengths. The produced material was dense, with a low defect density. The effects of the compaction pressure range, the alkaline activator amount, and the MSWI fly ash to bottom ash ratio were examined. We also used 5 wt% class-C fly ash, 5 wt% class-F fly ash, and/or 1 wt% epoxy as additives. This study may open a door to advanced MSWI ash upcycling approaches, useful to environmental preservation and sustainability.

Effects of fly and coal bottom ash ratio on backfill material performance

Fly ash (FA) and coal bottom ash (CBA) were selected to study the effects of their ratios on backfill materials. The rheological properties, stability, mechanical properties, crystal structure, and microstructure of backfill materials were investigated at different FA/CBA ratios. Increased FA/CBA values improved the slump, rheological performance, setting time, mechanical strength, and elastic modulus. However, the excellent water retention of CBA reduced the bleeding capacity, and the alkali-activated reaction by CBA generated a large amount of ettringite (AFt) that produced early strength. In the late period, the FA/CBA values affected the morphology and compactness of the calcium-silicate-hydrate gels. Furthermore, the performance of backfill materials with 0.5% superplasticizer and 30%-50% FA/CBA ratio could satisfy the requirements, and this formula has been applied to the filling mining project.

Experimental and Numerical Investigation on Flexural and Crack Failure of Reinforced Concrete Beams with Bottom Ash and Fly Ash

In this study, the effects of bottom ash and fly ash on the crack and flexural behaviour of reinforced concrete beams (RCBs) are observed considering experimental and 3D finite element analysing. For experimental tests, 3 different aggregate sizes are used for 4 different concrete series in the laboratory. Then, fly ash is added to concrete mixture with bottom ash to better seen the effect of fly ash ratio on the cracks and flexure behaviour of RCBs. Created RCBs are subjected to the flexural and crack testing in a fully organized laboratory. According to test results, flexural and crack behaviours of the RCBs are examined. Moreover, experimental tests are confirmed by numerical analyses by using ANSYS software. Accordingly, it is observed that each ash ratio in the concrete mixture has different flexural and crack effects on the RCBs for experimental and numerical tests. Then, a concrete structure is modelled using SAP2000 software to investigate the effects of fly and bottom ash ratio on the structures under earthquakes. Totally, 3 different seismic analyses are performed using SAP2000 software, and the seismic effects of bottom and fly ash ratio on the horizontal displacements of each floor are clearly seen in detail.

Plasticity and compaction characteristics on soft clay stabilised with coal ash and cement

This paper aims to determine the compaction and plasticity properties of marine clay stabilized with increasing percentages and different ratios of coal ash with cement. Coal ash with different ratio of bottom ash and fly ash (70:30, 50:50, and 30:70) were prepared at increasing percentages. Limited amount of ordinary Portland cement of 2% was added. The percentage of additives added to the marine clay were 5%, 8%, 10%, 15%, 20% and 25%, respectively. Standard Proctor test was done to determine the compaction characteristics while Atterberg limits was executed to acquire the plasticity characteristics of treated marine clay soil. In terms of plasticity, by increasing the additives percentages, the marine clay approaches CL group of plasticity which shows improvement in soil’s plasticity. For compaction, the values of MDD of treated marine clay is higher while the OMC is lower when compare to untreated. Hence, with the addition of coal ash waste there is improvement in terms of soil’s plasticity for all three ratios whilst for compaction values of treated marine clay does not change significantly between ratios.

Determination of ash forming characteristics and fouling/slagging behaviours during gasification of masson pine in a fixed-bed gasifier

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. • This study reported ash forming characteristics in biomass fixed-bed gasification. • A detailed comparison of fly ash and bottom ash in terms of ash slagging was given. • The composition and micro-morphology of bottom ash and fly ash were both analyzed. • The Si/(Ca + Mg) ratio of bottom ash (1.10) was lower than that of fly ash (1.29). • The ash fusion temperatures for the fly ash were higher than those for bottom ash.

Effect of Alkali-Activator to Bottom Ash Ratio on the Undrained Shear Strength of Bottom Ash based Geopolymer

Coal ash is generated as a raw product during combustion in thermal power plants. These industrial wastes include fly ash and bottom ash, which has been deemed as a source materials for geopolymer. Bottom ash is used in soil columns for stabilizing foundation soil. In the present study bottom ash from Tanjung bin power station was used as a substitute materials for making geopolymers. The effect of alkali activator to bottom ash ratio on the undrained shear strength of bottom ash based geopolymer was studied. The molarity of sodium silicate solution was kept as 14, Na2SiO3/NaOH of ratio 2.5, mass ratio of alkali activator to bottom ash 0.40, 0.50 and 0.60, and steam curing at 65°C were attempted for the samples. The experimental results of UU triaxial test indicate that alkali-activator to bottom ash ratio of 0.50 gives higher undrained shear strength.

Mechanical and physical properties of bottom ash/fly ash geopolymer for pavement brick application

Geopolymers are amorphous to semi-crystalline with excellent physical and and mechanical properties. It has been used to become a potential binder to Ordinary Portland Cement (OPC) in certain applications due to its lower emission of carbon dioxide gases and low energy consumption sustainability criteria. Bottom Ash (BA) is one of the main industrial by-products and it is produced at the bottom of the furnace during the coal combustion process in electricity generation. The application of BA as a sustainable construction material in the building industry plays an important role in order to decrease the volume of residual waste and conserving existing natural fine aggregates. The objectives for this study is to study the effect of fly ash to bottom ash ratio and to determine the optimum ratio of fly ash to bottom ash geopolymer for pavement brick application. The chemical composition and morphology of geopolymer reinforcement was analysed by using X-ray Fluorescence and Scanning Electron Microscope. The molarity of the Sodium Hydroxide solution is fixed at 12M. The parameter used in this study are different weight percentage of fly ash geopolymer 0 wt%, 10 wt%, 20 wt%, 30 wt% and 40 wt%. The solid to liquid ratios for this study is 2.0. The curing temperature of this study is 80°C and the curing time is 24 hours. 100% of bottom ash geopolymer is used as a control variable for this study.

Used of bottom ash waste from power plant and tailing as mine backfill

The using of bottom ash and tailing were by product from Mae Moh coal fired power plant as mine backfill. Laboratory was investigated the chemical, physical and mechanical properties of backfill containing bottom ash, tailing and cement. Using cast of backfill materials to test the ability of compressive strength in box size 5×5×5 cm. Four different types of backfill that portland cement type 1 was replaced by bottom ash, in the proportion of percent 5, 10, 15 and 20 by weight uncured and cured in water for 7 and 28 days. Backfill materials characterization bottom ash have been examined in grain size distribution, chemical composition analyzed by X-ray fluorescence (XRF) of backfill material. For the mechanical property was test by uniaxial compressive strength machine. The result was found that mixing ratio of bottom ash can be used as backfill material ranging from 15-20 % by weight. The mechanical property of backfill mixture suitable for use with compressive strength from 6.4-19.7 MPa and cured in water 28 days was maximum compressive strength.

Fly Ash and Bottom Ash Utilization as Geopolymer: Correlation on Compressive Strength and Degree of Polymerization Observed using FTIR

Concerning on the dependancy of coal on electric generation wordwidely, study on fly ash, thesolid waste of fired coal electricity generation, has been comprehensively conducting, i.e. geopolymer, cenosphere, soil remediation, and adsorbent. However, only few studies dealing with the utilization of bottom ash. Having of about 53% of coal in the 2050 energy mix, Indonesia will be dealing with more than 200 million tonnes of fly ash and bottom ash (FABA). In this study, FABA was mixed in certain proportion of 50:50, 75:25, dan 100:0. The formation of geopolymer was conducted with sodium hydroxide and sodium silicate in certain concentration. Once the mixture had been homogenized, it was casted and cured in varied temperature of 30, 60, dan 90 oC with curing time of 1, 3, 5, 14, 21, dan 28 days. In each curing time, sample was then analyzed using compresive strength apparatus and FTIR in order to observed the geopolimerization of the FABA mixture. It was found that compressive strength representing the macro characteristic of the geopolymer is in line with the CORR analysis of the FTIR results showing that the formation of aluminosilicate is responsible for the mechanical strength of the geopolymer. The higher the bottom ash ratio in the mixture with decrease the strength of the geopolymer in the order of one per second. Higher temperature results higher compresive strength to the value of 42 Mpa (FABA ratio is 75:25 at temperature of 90 oC) above the Indonesian standard for concrete. From this study, kinetics of FABA geopolymerization can be generated in accordance todiffusion model with R2 of 0.9135. Thus the utilization of FABA for geopolymer is going to be a potential solution to overcome the increasing amount of FABA resulted from fired coal electrical generation in Indonesia.

Comparison between Cement and Concrete Waste on the Strength Behaviour of Marine Clay Treated with Coal Ash

This paper aims to compare the strength behaviour of demolished concrete material (DCM) and ordinary Portland cement (OPC) in addition to coal ash for stabilizing marine clay, thus determining the optimum mix. Coal ash with different ratio of bottom ash (BA) and fly ash (FA) were prepared at various percentages (i.e. 3%, 6% and 8%). In addition, limited amount of DCM and OPC of 2% was added at different curing periods of 0, 7 and 28 days respectively. Thus, the percentage of admixture added to the marine clay were 5%, 8% and 10% respectively. Unconfined compressive strength (UCS) test was done and the results revealed that the strength of treated marine clay soil increased significantly with increment percentage of coal ash and also for both DCM and OPC. For admixture with OPC, treated marine clay with 5% admixture shows the highest strength gained, while the effective combination between bottom ash and fly ash is 50:50. At the first 7 days the strength gain was very high but from 7 days to 28 days the gain of strength was reduced. While for DCM, 5% of additive at 30BA:70FA shows the highest strength. In addition, both OPC and DCM provide significant strength gained between 0-7 days and decrease for 7-28 days. In conclusion, when comparing both stabilizer, OPC is a much more efficient secondary stabilizer when reacted with coal ash. As it provide early gain in strength with a much higher strength.

Impact of co-landfill proportion of bottom ash and municipal solid waste composition on the leachate characteristics during the acidogenesis phase

Incineration has become an important municipal solid waste (MSW) treatment strategy, and generates a large amount of bottom ash (BA). Although some BA is reused, much BA and pretreatment residues from BA recycling are disposed in landfill. When BA and MSW are co-landfilled together, acid neutralization capacity and alkaline earth metal dissolution of BA, as well as different components of MSW may change environmental conditions within the landfill, so the degradation of organic matter and the physical and chemical properties of leachate would be affected. In this study, the effect of co-landfilled BA and MSW on the leachate characteristics during the hydrolysis and acidogenesis phase was studied using different BA/MSW ratios and MSW compositions. The results showed that the co-landfill system increased leachate pH, electric conductivity and alkalinity. For MSW with a high content of degradable components, the release and degradation of total organic carbon (TOC) and volatile fatty acids (VFA) from MSW were promoted when the BA ratio by wet weight was less than 50%, and the biodegradability of leachate was improved. When the BA ratio exceeded 50%, the degradation of organic matters was inhibited. For MSW with low content of degradable components, when the proportion of BA was less than 20%, the release and degradation of TOC and VFA from MSW were promoted and alkalinity increased. When the BA ratio exceeded 20%, the degradation of organic matters was inhibited. The 50% BA ratio could improve the bio-treatability of leachate indicated by the leachate pH and C/N ratio. However, BA inhibited the release of nitrogen (TN and NH4+-N) at all BA ratios and MSW compositions. At the same time, the addition of BA increased the risk of leachate collection system clogging due to the dissolution and re-precipitation of alkaline earth metals contained in BA.

Performance of bricks made using fly ash and bottom ash

This paper presents the findings of investigation carried out on bricks made using fly ash and bottom ash using a non-conventional method. Bricks were cast using self-compacting mixtures of bottom ash, fly ash and cement eliminating both pressing and firing. Bricks were then tested for compressive strength, modulus of rupture, ultrasonic pulse velocity (UPV), water absorption, initial rate of suction, fire resistance and durability. The results showed better performance compared to conventional clay bricks in the properties investigated. Compressive strength was between 7.13 and 17.36MPa, while UPV ranged from 2.2 to 2.96km/s. Increase in fly ash reduced the water absorption. Tests for fire resistance indicated that the bricks did not show any spalling, and, there was increase in strength of up to 30% after heating. The optimum ratio of bottom ash, fly ash and cement was found to be 1:1:0.45 for better performance of bricks. It is concluded that bricks developed in this study can be used as an alternative to conventional bricks and hence can contribute to sustainable development.

Strength and Physico-chemical Characteristics of Fly Ash–Bottom Ash Mixture

The quantity of coal combustion products, particularly fly ash (FA) and bottom ash (BA), has been increasing from coal power plants around the world. The major problem of a coal combustion-based power plant is that it produces huge quantities of solid waste. Recently, there have been efforts to use FA and BA together as a mixture in construction works. This paper investigates morphology and chemical and strength characteristics of an FA–BA mixture for various curing periods. Scanning electron microscopy (SEM), X-ray fluorescence (XRF), and consolidated undrained triaxial tests were used to determine the physico-chemical characteristics of the mixture. Based on SEM results, it was found that, with an increasing ratio of BA to FA, the number of irregular particles in the mixture increased. The results of XRF indicated noticeable changes in the surface composition of both FA and BA particles after mixing. The physico-chemical test results indicate the formation of a new gel form product in the mixture, which has been identified as calcium silicate hydrate (C-S-H). From an engineering point of view, the results indicated that the value of modulus of elasticity decreases with increasing BA content, from 30 to 70 %, in the ash mixture. However, the increase in BA from 30 to 70 % did not have any significant effect on the shear strength of the FA–BA mixture.

Impact of MSWI bottom ash codisposed with MSW on landfill stabilization with different operational modes.

The aim of the study was to investigate the impact of municipal solid waste incinerator (MSWI) bottom ash (BA) codisposed with municipal solid waste (MSW) on landfill stabilization according to the leachate quality in terms of organic matter and nitrogen contents. Six simulated landfills, that is, three conventional and three recirculated, were employed with different ratios of MSWI BA to MSW. The results depicted that, after 275-day operation, the ratio of MSWI BA to fresh refuse of 1 : 10 (V : V) in the landfill was still not enough to provide sufficient acid-neutralizing capacity for a high organic matter composition of MSW over 45.5% (w/w), while the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V) could act on it. Among the six experimental landfills, leachate quality only was improved in the landfill operated with the BA addition (the ratio of MSWI BA to fresh refuse of 1 : 5 (V : V)) and leachate recirculation.

Population balance for CFB–FGD systems

Abstract Population balance is the basis of stable and effective operation of circulating fluidized bed flue gas desulfurization systems (CFB–FGD systems). The population balance model parameters were calibrated by comparing the calculated results for a CFB–FGD system with experimental data from a bench-scale CFB–FGD system. The relative error was less than 5.1%. The influences of the model parameters, reactor structures, operating conditions, and adhesive carrier particles on the population balance of the CFB–FGD system were then analyzed using the calibrated population balance model. The results indicated that particle segregation and the superficial gas velocity strongly influenced the particle size distribution. The cyclone separation efficiency and the selected particle draining coefficient also impacted the particle size distribution and the bottom ash ratio. The calcium to sulfur ratio and the bed temperature mainly influenced the bottom ash ratio and the desulfurization efficiency of the system. The anti-abrasion characteristics of the rapidly hydrated sorbent influenced the particle size distribution, the bottom ash ratio, and the desulfurization efficiency of the system. The population balance in the CFB–FGD system was more easily achieved when circulating ash from a CFB boiler was used as adhesive carrier particles instead of coal fly ash. This research provides guidance for stable, effective operation of CFB–FGD systems to promote industrial applications of CFB–FGD technology.

Effects of High Volumes of Fly Ash, Blast Furnace Slag, and Bottom Ash on Flow Characteristics, Density, and Compressive Strength of High-Strength Mortar

This paper presents results of an experimental work carried out to evaluate utilization of recycled materials, such as fly ash and bottom ash (by-products of thermoelectric power plants), and blast furnace slag (by-products of ironworks) as binders and aggregates with high volume in high-strength, lightweight mortar. The effects of high volumes of fly ash, blast furnace slag, and bottom ash on flow character- istics, density, and compressive strength of mortar were investigated. In addition, the water capillary absorption characteristics of mortar regarding moisture transport that may affect the durability of the mortar were studied. It was found that the flow characteristics of fresh mortar were neither changed nor decreased with the increase in the replacement ratio of bottom ash, while these were improved by the use of high volumes of fly ash and blast furnace slag as replacements of cement. DOI: 10.1061/(ASCE)MT.1943-5533.0000624. © 2013 American Society of Civil Engineers. CE Database subject headings: Mortars; Fly ash; Bottom ash; Recycling; Mechanical properties; Absorption; Compressive strength. Author keywords: High-strength lightweight mortar; Fly ash; Blast furnace slag; Bottom ash; Recycled materials; Mechanical properties; Water capillary absorption.