Influence of MgO on Properties and Microstructure of Mullite Ceramics Synthesized from Coal Fly Ash

The effects of MgO and temperature on the properties and microstructure of mullite ceramics synthesized from high-aluminium coal fly ash and bauxite are investigated in this paper. The results show that when the batch containing 4 wt% MgO is heated from 1100 °C to 1500 °C, the bulk density and flexural strength increase obviously with the sintering temperature rising, mullite ceramics with flexural strength as high as 169 MPa can be obtained at 1500 °C with the addition of 2 wt% MgO. According to the XRD results, the corundum, cordierite and cristobalite phases disappear completely upon 1400 °C, it indicates that MgO addition may effectively promote sintering process. The results of SEM indicate that the prepared ceramics mainly exist in the shape of long parallelepipeds with the aspect ratio of about 7-10.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.587 ◽

2007 ◽

Vol 561-565 ◽

pp. 587-590 ◽

Cited By ~ 1

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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Mullite ceramics derived from coal fly ash

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(02)85967-7 ◽

2002 ◽

Vol 43 (3) ◽

pp. 213-214

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Mullite Ceramics

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Sintering Process and Characteristics of Glass-Ceramics from Coal Fly Ash

Advances in Powder and Ceramic Materials Science - The Minerals, Metals & Materials Series ◽

10.1007/978-3-030-36552-3_1 ◽

2020 ◽

pp. 3-13

Author(s):

Li Zeng ◽

Hongjuan Sun ◽

Tongjiang Peng ◽

Wenmiao Zheng

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Glass Ceramics ◽

Sintering Process

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Effect of Fly Ash on the Properties of Ceramics Prepared from Steel Slag

Applied Sciences ◽

10.3390/app8071187 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1187 ◽

Cited By ~ 5

Author(s):

Yanbing Zong ◽

Xuedong Zhang ◽

Emile Mukiza ◽

Xiaoxiong Xu ◽

Fei Li

Keyword(s):

Fly Ash ◽

Flexural Strength ◽

Water Absorption ◽

Sintering Temperature ◽

Steel Slag ◽

Diffraction Peak ◽

National Standard ◽

Sintered Ceramic ◽

Base Steel ◽

Sintering Shrinkage

In this study, SiO2–Al2O3–CaO–MgO steel slag ceramics containing 5 wt % MgO were used for the preparation of ceramic bodies, with the replacement of 5–20 wt % quartz and feldspar by fly ash. The effect of the addition of fly ash on the sintering shrinkage, water absorption, sintering range, and flexural strength of the steel slag ceramic was studied. Furthermore, the crystalline phase transitions and microstructures of the sintered samples were investigated by XRD, Fourier transform infrared (FTIR), and SEM. The results showed that the addition of fly ash affected the crystalline phases of the sintered ceramic samples. The main crystal phases of the base steel slag ceramic sample without fly ash were quartz, diopside, and augite. With increasing fly ash content, the quartz diffraction peak decreased gradually, while the diffraction peak intensity of anorthite became stronger. The mechanical properties of the samples decreased with the increasing amount of fly ash. The addition of fly ash (0–20 wt %) affected the optimum sintering temperature (1130–1160 °C) and widened the sintering range. The maximum addition amount of fly ash should be 15 wt %, for which the optimum sintering temperature was 1145 °C, water absorption was 0.03%, and flexural strength was 43.37 MPa higher than the Chinese national standard GBT 4100-2015 requirements.

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Extracting Alumina from Coal Fly Ash with Ammonium Sulfate Sintering Process

Light Metals 2012 ◽

10.1002/9781118359259.ch38 ◽

2012 ◽

pp. 213-217 ◽

Cited By ~ 1

Author(s):

Laishi Li ◽

Xinqin Liao ◽

Yusheng Wu ◽

Yingying Liu

Keyword(s):

Fly Ash ◽

Ammonium Sulfate ◽

Coal Fly Ash ◽

Sintering Process

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Statistical Analysis of the Tensile Strength of Coal Fly Ash Concrete with Fibers Using Central Composite Design

Advances in Materials Science and Engineering ◽

10.1155/2015/486232 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Marinela Barbuta ◽

Emanuela Marin ◽

Sorin Mihai Cimpeanu ◽

Gigel Paraschiv ◽

Daniel Lepadatu ◽

...

Keyword(s):

Tensile Strength ◽

Fly Ash ◽

Flexural Strength ◽

Central Composite Design ◽

Glass Fiber ◽

Coal Fly Ash ◽

Response Surfaces ◽

Split Tensile Strength ◽

Fly Ash Concrete ◽

Central Composite

The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength). From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%.

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Preparation of 10B Enriched B4C Ceramics by Pressureless Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.540 ◽

2014 ◽

Vol 602-603 ◽

pp. 540-543

Author(s):

Yu Jun Zhang ◽

Sha Li Tan ◽

Ru Bin Wei ◽

Shu He Ai ◽

Hai Bin Sun

Keyword(s):

Flexural Strength ◽

Boron Carbide ◽

Relative Density ◽

Sintering Temperature ◽

Raw Material ◽

Carbide Powder ◽

Average Particle ◽

Strength Increase ◽

Pressureless Sintering ◽

Water Reactors

Boron carbide is an attractive neutron absorbing material used both in Fast Breeder Reactors (FBR) and in Pressurised Water Reactors (PWR) owing to its very high absorption cross section for thermal neutrons, chemical stability and refractory character. In the present paper, 10B enriched B4C ceramics are prepared by pressureless sintering at 19602160°C, under argon, using 10B boron carbide powder as raw material, 18 wt% phenolic resin as sintering aid. In the sintering temperature range, with the increasing of sintering temperature, both the relative density and flexural strength increase linearly, the average particle sizes increase from about 3μm at 1960°C to more than 30μm at 2160°C. The sample sintered at 1960°C has a 91.7% of relative density and 192 MPa of flexural strength and a homogeneous texture with 3-4μm particle size, which are enough for pellet application of reactors.

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Effect of Fly Ash/Alkaline Activator Ratio and Sodium Silicate/NaOH Ratio on Fly Ash Geopolymer Coating Strength

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.594-595.146 ◽

2013 ◽

Vol 594-595 ◽

pp. 146-150 ◽

Cited By ~ 2

Author(s):

J. Liyana ◽

Abdullah Mohd Mustafa Al Bakri ◽

Kamarudin Hussin ◽

C.M. Ruzaidi ◽

A. Rashid Azura

Keyword(s):

Fly Ash ◽

Flexural Strength ◽

Sodium Silicate ◽

Sintering Temperature ◽

Coating Material ◽

Liquid Ratio ◽

Alkali Activator ◽

Alkaline Activator ◽

Solid Liquid ◽

Exposure Conditions

Fly ash geopolymer coating material potential used to protect surface used in exposure conditions. Ratio of fly ash/alkaline activator and Na2SiO3/NaOH play important parameter on determining the best flexural strength of geopolymer coating material. Fly ash and alkali activator (Al2O3/Na2SiO3) were mixed with the solids-to-liquid ratios in range of 1.0-3.0 and different ratios of Na2SiO3/NaOH (1.0-3.0) to prepare geopolymer coating material at constant NaOH concentration of 10 M. Effect of fly ash/alkaline activator ratio and Na2SiO3/NaOH on geopolymer coating was determined with respect to the highest flexural strength of the 1200oC sintering temperature of geopolymer coating substrates. The results concluded that the highest strength for fly ash geopolymer coating material is achieved 42 MPa when the solid/liquid ratio is 2.0 and the Na2SiO3/NaOH ratio is 2.5.

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