Adhesion strength and thermal shock resistance of fly ash cenospheres deposited on SiC

2010 ◽  
Vol 61 (11) ◽  
pp. 1299-1303 ◽  
Author(s):  
A. Chávez-Valdez ◽  
J.M. Almanza-Robles ◽  
G. Vargas-Gutiérrez ◽  
A. Arizmendi-Morquecho
Keyword(s):  
Fly Ash ◽  
Thermal Shock ◽  
Adhesion Strength ◽  
Thermal Shock Resistance ◽  
Shock Resistance ◽  
Fly Ash Cenospheres

Utilization of Fly Ash in the Synthesis of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 321 ◽  
pp. 131-140
Author(s):  
Martin Nguyen ◽  
Radomír Sokolař
Keyword(s):  
Thermal Expansion ◽  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Power Plants ◽  
Linear Thermal Expansion ◽  
Aluminium Oxide ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Shock Resistance

Forsterite refractory ceramics is utilized in the metallurgical and cement industries as a lining of metallurgical furnaces and rotary kilns for its high refractoriness up to 1850°C and refractoriness under load above 1600°C. Another significant property of forsterite is its coefficient of linear thermal expansion utilized in the electrotechnical industry for ceramic-metal joints. Addition of aluminium oxide into the raw material mixture results in creation of magnesium-alumina spinel (MgO·Al2O3) which improves sintering, thermal shock resistance and mechanical properties in comparison with pure forsterite ceramics. Inexpensive source of aluminium oxide is fly ash. Utilization of fly ash, secondary energetic product of coal-burning power plants, is important for the environment and sustainable development. This paper evaluated properties of fly ash-based forsterite-spinel ceramics in comparison with alumina-based forsterite-spinel ceramics. Forsterite-spinel ceramics was synthesized from olivine, calcined magnesite and fly ash/alumina powders. XRD analysis was used to determine mineralogical composition, thermal analyses were used to determine the behaviour during firing and scanning electron microscopy to determine the morphology of crystal phases. Refractoriness of pyrometric cones, refractoriness under load, thermal shock resistance, coefficient of linear thermal expansion, water absorption, porosity and modulus of rupture were also determined on fired test samples.

Thermal and Thermomechanical Properties of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 174-180
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Thermal Analyses ◽  
Aluminium Oxide ◽  
Thermomechanical Properties ◽  
Modulus Of Rupture ◽  
Shock Resistance

This article examines the utilization of fly ash in comparison with alumina as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1500°C for 2 hours. Sintered samples were characterized by X-ray diffraction analysis and scanning electron microscopy. Samples were also subjected to determination of porosity, water absorption and bulk density. Thermal and thermomechanical properties were determined by thermal analyses, refractoriness, refractoriness under load, thermal shock resistance and thermal dilatometric analysis with determination of thermal expansion coefficient. Mixtures with 10 wt.% and 20 wt.% of fly ash had the most promising results compared to alumina mixtures. Thermal shock resistance and modulus of rupture were improving with increasing content of aluminium oxide in the mixture.

Preparation and Properties of MgO-MgAl2O4-FeAl2O4 Bricks in Cement Kiln

2011 ◽  
Vol 250-253 ◽  
pp. 554-560 ◽  
Author(s):  
Shu Long Ma ◽  
Yong Li ◽  
Jia Lin Sun ◽  
Yue Li ◽  
Wen Bin Xia
Keyword(s):  
Compressive Strength ◽  
Thermal Shock ◽  
Adhesion Strength ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Volume Density ◽  
Cement Kiln ◽  
Particle Sizes ◽  
Tunnel Furnace ◽  
Shock Resistance

Sintered magnesia with different particle sizes, fused MgAl2O4and FeAl2O4were used as the raw materials. FeAl2O4is added in MgO-MgAl2O4bricks at different ratios to gradually replace MgAl2O4. After the raw materials were molded and sintered at the tunnel furnace with the temperature 1 530°C for 10 hours, the MgO-MgAl2O4-FeAl2O4bricks could be made. After the analysis of the phase composition, microstructure and routine performance of the specimens, the influence by adding FeAl2O4to the samples on the properties such as thermal shock resistance, adhesion strength of kiln crust are discussed as the key point. The result shows that the addition of FeAl2O4has no evidently influence on the apparent porosity and volume density. The cold compressive strength of the samples reduces gradually with the addition of FeAl2O4, and it decreases obviously when the amount of FeAl2O4is more than 8%. When the addition of FeAl2O4is 5% FeAl2O4in the MgO-MgAl2O4-FeAl2O4bricks, MgAl2O4and FeAl2O4can combine each other’s advantages. The thermal shock resistance not only decreased obviously but the adhesion strength to kiln crust is increased.

scholarly journals Impact of Fly Ash as a Raw Material on the Properties of Refractory Forsterite–Spinel Ceramics

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 835
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Power Plants ◽  
Raw Materials ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Shock Resistance ◽  
Refractory Ceramics ◽  
The Impact

This article examines the process for the synthesis of forsterite–spinel (2MgO·SiO2/MgO·Al2O3) refractory ceramics from fly ash and alumina as sources of aluminum oxide. Raw materials were milled, mixed in different ratios and sintered at 1500 °C for 2 h. Sintered samples were characterized by XRD, thermal analyses and SEM. Porosity, water absorption, bulk density, refractoriness, refractoriness under load and thermal shock resistance were also investigated. The impact of fly ash as a raw material was investigated in accordance with the resulting properties and microstructure of samples with fly ash and alumina as the raw materials. Due to the positive effect of flux oxides (iron oxides and alkalis) on sintering, the mullite contained in fly ash completely decomposed into silica and alumina, which, together with magnesium oxide, formed spinel. This led to improved microstructural and mechanical properties and thermal shock resistance. In particular, mixtures with 10 wt.% and 20 wt.% of fly ash had the most promising results compared to alumina mixtures. Both modulus of rupture and thermal shock resistance were improved, while the impact on refractory properties was minimal. The novelty of this research lies in the recycling of fly ash, a by-product from coal-burning power plants, into a raw material for the production of forsterite–spinel refractory ceramics.

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