scholarly journals Synergistic Sintering of Lignite Fly Ash and Steelmaking Residues towards Sustainable Compacted Ceramics

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
V. G. Karayannis ◽  
A. K. Moutsatsou ◽  
A. N. Baklavaridis ◽  
E. L. Katsika ◽  
A. E. Domopoulou
Keyword(s):  
Fly Ash ◽  
Sintering Temperature ◽  
Value Added ◽  
Mineralogical Composition ◽  
Ceramic Materials ◽  
Raw Material ◽  
Processing Temperature ◽  
Lignite Fly Ash ◽  
Experimental Findings

The development of value-added ceramic materials deriving only from industrial by-products is particularly interesting from technological, economic, and environmental point of views. In this work, the synergistic sintering of ternary and binary mixtures of fly ash, steelmaking electric arc furnace dust, and ladle furnace slag for the synthesis of compacted ceramics is reported. The sintered specimens’ microstructure and mineralogical composition were characterized by SEM-EDS and XRD, respectively. Moreover, the shrinkage, apparent density, water absorption, and Vickers microhardness (HV) were investigated at different sintering temperatures and raw material compositions. The characterization of the sintered compacts revealed the successful consolidation of the ceramic microstructures. According to the experimental findings, the ceramics obtained from fly ash/steel dust mixtures exhibited enhanced properties compared to the other mixtures tested. Moreover, the processing temperature affected the final properties of the produced ceramics. Specifically, a 407% HV increase for EAFD and a 2221% increase for the FA-EAFD mixture were recorded, by increasing the sintering temperature from 1050 to 1150°C. Likewise, a 972% shrinkage increase for EAFD and a 577% shrinkage increase for the FA-EAFD mixture were recorded, by increasing the sintering temperature from 1050 to 1150°C. The research results aim at shedding more light on the development of sustainable sintered ceramics from secondary industrial resources towards circular economy.

Synthesis and Characterization of Cordierite, Mullite and Cordierite-Mullite Ceramic Materials using Coal Fly Ash as Raw Material

MRS Advances ◽  
2017 ◽  
Vol 2 (62) ◽  
pp. 3865-3872
Author(s):  
J. López-Cuevas ◽  
E. Interial-Orejón ◽  
C.A. Gutiérrez-Chavarría ◽  
J.C. Rendón-Ángeles
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Vickers Microhardness ◽  
Coal Fly Ash ◽  
Ceramic Materials ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Mullite Ceramic ◽  
Two Temperatures

AbstractCordierite (Mg2Al4Si5O18), Mullite (Al4+2xSi2-2xO10-x) and Cordierite-Mullite ceramic materials were obtained from a stoichiometric mixture of coal fly ash (CFA) as a source of SiO2 and Al2O3, plus high-purity MgO and Al2O3. The starting stoichiometric mixtures were homogenized, and then uniaxially pressed, cold isostatically pressed, and sintered at 1200-1600 °C for 2-5 h. The sintered materials were characterized by X-ray diffraction, scanning electron microscopy, Vickers microhardness, density and four-point flexural strength. In general, the desired phases tended to form in the composites at temperatures of 1350 or 1400 °C, with a considerable amount of glassy phase developing from 3 h onwards at one of those two temperatures, depending on the composite composition. The microstructure of the composites consisted of a matrix of Cordierite and interwoven needles of Mullite. The bulk density decreased, while the flexural strength and the Vickers microhardness increased with increasing nominal content of Mullite in the composites. A synergistic effect taking place between Cordierite and Mullite enhances the mechanical properties of the composites.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF GREENER CERAMIC MATERIALS WITH LOWER THERMAL CONDUCTIVITY USING OLIVE MILL SOLID BYPRODUCT

2020 ◽  
Vol 1 ◽  
pp. 96-106 ◽  
Author(s):  
Xenofon Spiliotis ◽  
Vayos Karayannis ◽  
Stylianos Lamprakopoulos ◽  
Konstantinos Ntampegliotis ◽  
George Papapolymerou
Keyword(s):  
Thermal Conductivity ◽  
Solid Waste ◽  
Energy Savings ◽  
Sintering Temperature ◽  
Ceramic Body ◽  
Ceramic Materials ◽  
Raw Material ◽  
Gravimetric Analysis ◽  
Olive Mill Solid Waste ◽  
Olive Mill

In the current research, the valorization of olive mill solid waste as beneficial admixture into clay bodies for developing greener ceramic materials with lower thermal conductivity, thus with increased thermal insulation capacity towards energy savings, is investigated. Various clay/waste mixtures were prepared. The raw material mixtures were characterized and subjected to thermal gravimetric analysis, in order to optimize the mineral composition and maintain calcium and magnesium oxides content to a minimum. Test specimens were formed employing extrusion and then sintering procedure at different peak temperatures. Apparent density, water absorption capability, mechanical strength, porosity and thermal conductivity were determined on sintered specimens and examined in relation to the waste percentage and sintering temperature. The experimental results showed that ceramic production from clay/olive-mill solid waste mixtures is feasible. In fact, the mechanical properties are not significantly impacted with the incorporation of the waste in the ceramic body. However, the thermal conductivity decreases significantly, which can be of particular interest for thermal insulating materials development. Furthermore, the shape of the produced ceramics does not appear to change with the sintering temperature increase.

Innovative Synergistic Valorization of Lignite Fly Ash and Steel Industry Scrap-Soil as Secondary Resources for Compacted Ceramics

2015 ◽  
Vol 660 ◽  
pp. 268-272 ◽  
Author(s):  
V. Karayannis ◽  
G. Papapolymerou ◽  
S. Zaoutsos ◽  
S. Lamprakopoulos ◽  
K. Ntampegliotis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Steel Industry ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hydraulic Press ◽  
Power Station ◽  
Secondary Resources ◽  
Lignite Fly Ash ◽  
Diametral Tensile Strength

In the present research, the combined utilization of fly ash (FA), derived from a lignite-fed power station, along with scrap-soil (SS), a steel industry by-product, is investigated, for the development of eco-friendly ceramics, thus enhancing innovation and sustainability. The valorization of these low price and largely available industrial secondary resources as 100% the raw materials mixture in ceramic industry arises interesting technological, environmental and economical benefits. FA and SS were mixed in various proportions (0-70%wt. in SS), cold compacted at 20 tn load using an automated hydraulic press to form a series of 5 cm diameter disc-shaped specimens, and finally sintered at three different peak temperatures (1000oC, 1100oC and 1140oC) for 3h. Then, the specimen microstructure and physico-mechanical properties were characterized. According to the experimental results, a sintering temperature increase from 1000°C up to 1140oC significantly improves specimen densification, thus sharply enhancing the diametral tensile strength (DTS), from 0.5 MPa up to 12.8 MPa respectively for a 50-50%wt. FA-SS mixture. Mechanical strength also varies with the SS percentage in the raw materials. Physico-mechanical properties seem to be constant for specimens containing SS up to 60% at 1140oC.

Image Analysis of Fly Ash in the Characterization of the Shape of the Grains

1994 ◽  
Vol 370 ◽  
Author(s):  
M. Barrioulet ◽  
H. Cros ◽  
B. Husson ◽  
E. Ringot
Keyword(s):  
Image Analysis ◽  
Fly Ash ◽  
Mineralogical Composition ◽  
Fly Ashes ◽  
Particle Content ◽  
Power Stations ◽  
Fresh Material ◽  
Quantitative Image ◽  
Strength And Durability

AbstractFly ash from power stations is used as concrete additive to improve strength and durability. Surprisingly, studies of ashes of identical mineralogical composition from two different places have reported different results in terms of the rheological properties of the fresh material. The viscosity of the pastes made from these different fly ashes seems to be linked to the proportion of spherical and smooth-shaped grains found in them. A quantitative image analysis was carried out to characterize the shape of the grains of these two ashes from different geographical origins. The main result proves that the higher the glassy particle content of the fly ash, the more the hydraulic matrix is fluid.

The Influence of Sintering Temperature on Ceramic Material with Addition of Mill Scale

2014 ◽  
Vol 798-799 ◽  
pp. 281-286
Author(s):  
J.G. Meller ◽  
A.B.C. Arnt ◽  
M.R. da Rocha
Keyword(s):  
Sintering Temperature ◽  
Chemical Characterization ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Loss On Ignition ◽  
Mill Scale ◽  
Ceramic Mass ◽  
Colorimetric Test ◽  
Scale Test

This work aims to evaluate the influence of temperature sintering of a ceramic mass to characterize the properties of a ceramic mass obtained with the addition of mill scale. This residue is consisting of iron oxides and can be used in replacing pigments used in ceramic materials. The constitution of mixture was performed after chemical characterization of the ceramic samples, with addition of 5% in weight of mill scale. Test specimens were sintered at temperatures of 900oC, 950oC and 1000oC. The samples were characterized by loss on ignition, linear shrinkage, water absorption, flexural strength by 3 points and colorimetric test. The results indicate that different firing temperatures influenced the strength and tone of the specimens tested and, allowing the application these materials as structural ceramic.

Characterization of North American Lignite Fly Ashes II. XRD Mineralogy

1987 ◽  
Vol 113 ◽  
Author(s):  
G. J. McCarthy ◽  
D. M. Johansen ◽  
A. Thedchanamoorthy ◽  
S. J. Steinwand ◽  
K. D. Swanson
Keyword(s):  
Fly Ash ◽  
Bituminous Coal ◽  
Coal Fly Ash ◽  
Fly Ashes ◽  
X Ray ◽  
Mining Areas ◽  
Lignite Fly Ash ◽  
Coal Fly Ashes ◽  
Ferrite Spinel

ABSTRACTX-ray powder diffraction has been used to determine the crystalline phase mineralogy in samples of fly ash from each of the lignite mining areas of North America. The characteristic phases of North Dakota lignite fly ashes were periclase, lime, merwinite and the sulfate phases anhydrite, thenardite and a sodalite-structure phase. Mullite was absent in these low-Al2O3 ashes. Montana lignite ash mineralogy had characteristics of ND lignite and MT subbituminous coal fly ashes; mullite and C3A were present and the alkali sulfates were absent. Texas and Louisiana lignite fly ashes had the characteristic mineralogy of bituminous coal fly ash: quartz, mullite, ferrite-spinel (magnetite) and minor hematite. Even though their analytical CaO contents were 7–14%, all but one lacked crystalline CaO-containing phases. Lignite fly ashes from Saskatchewan were generally the least crystalline of those studied and had a mineralogy consisting of quartz, mullite, ferrite spinel and periclase. Quantitative XRD data were obtained. The position of the diffuse scattering maximum in the x-ray diffractograms was indicative of the glass composition of the lignite fly ash.

Preparation and Characterization of the Ceramsites with Microscale Pores from Iron Tailing and Fly Ash

2020 ◽  
Vol 12 ◽  
Author(s):  
Zeyang Xue ◽  
Zi Wang ◽  
Chunhu Yu ◽  
Yajing Mao ◽  
Lizhai Pei
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Time ◽  
Duration Time ◽  
Important Significance ◽  
Scanning Electron

Background: Iron tailing causes great environmental and social problems which contaminate water, air and soil. Therefore, it is of important significance to prepare iron tailing ceramsites with microscale pores which can recycle the deposited iron tailing. Objective: The aim of the research is to obtain iron tailing ceramsites with microscale pores and good mechanical performance. Methods: The iron tailing ceramsites have been characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Influence of the content of iron tailing, temperature and duration time on the mechanical performance of the obtained ceramsites was performed and the optimal sintering parameter was determined. The bulk density, apparent density and cylinder compressive strength of the obtained ceramsites increase obviously as improving the iron tailing content, temperature and sintering time. Results: Duration time and sintering temperature play important roles in the formation and size of the pores of the ceramsites. The optimal iron tailing content and sintering parameter are 70wt.%, 1100 ℃ for 40 min. The iron tailing ceramsites mainly consist of orthorhombic CaAl2Si2O8, monoclinic CaSiO3, hexagonal Ca7Si2P2O16, triclinic MgSiO3, triclinic Al2SiO5 and triclinic Ca2Fe2O5 phases. Iron tailing ceramsites from 1100 ℃ for 40 min are composed of irregular particles with several hundreds of micrometers improving the density and strength of the ceramsites. Conclusion: Iron tailing ceramsites containing microscale pores were prepared using iron tailing and fly ash, and exhibit excellent potential for the application in the field of construction.

Characterization of Effloresences of Ambient and Elevated Temperature Cured Fly Ash Based Geopolymer Type Concretes

2016 ◽  
Vol 1139 ◽  
pp. 25-29 ◽  
Author(s):  
Jadambaa Temuujin ◽  
Claus Ruescher ◽  
Amgalan Minjigmaa ◽  
Burenkhangai Darkhijav ◽  
Batmunkh Davaabal ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Ambient Temperature ◽  
Mineralogical Composition ◽  
Curing Temperature ◽  
Calcium Carbonates ◽  
Sodium Calcium ◽  
High Calcium ◽  
High Calcium Fly Ash

Efflorescences formed on the surface of air (ambient) and elevated (70°C) temperatures cured high calcium fly ash based geopolymer type concretes have been characterized by the XRD, SEM-EDX and FTIR techniques. The mineralogical composition of the efflorescence depends on curing temperature. At ambient temperature the main phase of efflorescence consists of atmospheric carbonation product of sodium hydroxide such as thermonatrite (Na2(CO3)·H2O, PDF 8--448), while in the 70°C cured concrete it represents sodium calcium carbonates gaylussite (Na2Ca (CO3)2·5H2O, PDF 21-343). Mineralogical composition difference between the ambient and 70°C cured concrete’s efflolorescences is related to chemical reaction of alkaline liquid with fly ash constituents.

Preparation and Characterization of Al2O3 High Density Ceramic Materials

2013 ◽  
Vol 457-458 ◽  
pp. 266-269
Author(s):  
Chun Yan Jia ◽  
Dong Hong Li ◽  
Yong He Liu
Keyword(s):  
Sintering Temperature ◽  
Ceramic Materials ◽  
Volume Density ◽  
Raw Material ◽  
High Alumina ◽  
Molding Pressure ◽  
Alumina Powder ◽  
Alumina Ceramics ◽  
Shrinkage Ratio ◽  
Isostatic Compaction

With sub-micron alumina powder as raw material, high alumina ceramics were prepared through isostatic compaction. The volume density and shrinkage ratio were investigated. The influence of sintering temperature and molding pressure were studied on volume density and shrinkage ratio of ceramic. The results indicated that sintering characteristic of alumina ceramics could be improved at the appropriate sintering temperature and molding pressure and its sintering temperature could be decreased by using sub-micron alumina powder as raw material. 95 ceramics were prepared using sub-micron alumina as raw material, when the sintering temperature was 1550°C, molding pressure was 12 t, and ceramic volume density could be achieved 3.71g /cm3.

Preparation and Characterization of β-SiAlON Ceramics from High Aluminium Fly Ash via Carbothermal Reduction-Nitridation

2007 ◽  
Vol 561-565 ◽  
pp. 587-590 ◽  
Author(s):  
Jin Hong Li ◽  
Hong Wen Ma ◽  
Ying Cao
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Physicochemical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Carbothermal Reduction ◽  
Sintering Temperature ◽  
Sem Images ◽  
High Aluminium

In this work, β-sialon ceramics were prepared from high-aluminium fly ash via carbothermal reduction-nitridation (CRN) and the physicochemical properties of the materials such as bulk density, apparent porosity, water absorption and flexural strength were also discussed. The results showed that the percentage of β-sialon phase in the product decreases as the temperature increases from 1400°C and the weight of the sintered specimen experienced an increase during 1350°C~1450°C due to the nitridation reactions, and followed by a gradual decrease till 1550°C for the decomposition of β-sialon. It is indicated that the optimum sintering temperature to obtain the highest yield of β-sialon ~93% lies in 1400°C~1450°C. The SEM images revealed that the prepared β-sialon sintered at 1400°C were mainly in shape of elongated prisms, typically ~5μm in length and 0.5~1μm in width. As the temperature increased to 1500°C and above, β-sialon decomposed and the new phases of SiC and AlN were formed at 1550°C as confirmed by XRD.

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