Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials

In this paper, the two-stage sintering process as a promising strategy has been adopted to prepare high-performance porous ceramics with high porosity. Sewage sludge and waste coal ash were used as raw materials and added were starch and CaCO3 as a mixed foaming agent. The chemical composition of th...

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Main Authors: Esam Al-Qadhi, Gaiye Li, Yaxing Ni
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2019/3710692
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author Esam Al-Qadhi
Gaiye Li
Yaxing Ni
author_facet Esam Al-Qadhi
Gaiye Li
Yaxing Ni
author_sort Esam Al-Qadhi
collection DOAJ
description In this paper, the two-stage sintering process as a promising strategy has been adopted to prepare high-performance porous ceramics with high porosity. Sewage sludge and waste coal ash were used as raw materials and added were starch and CaCO3 as a mixed foaming agent. The chemical composition of the raw materials and mixed foaming agents were analyzed by standard techniques. All mixtures were prepared from fixed solid materials mixed at a ratio of 48 : 32 : 10 : 10 (wt.%) for coal ash, sludge, starch, and CaCO3, respectively, followed by granular molding, aging, sintering and property survey tests. The influence of heating rate, holding time, and heating temperature of the two stages on the characteristics of the as-obtained porous ceramics was deeply investigated. The properties investigated are apparent porosity, bulk density, compressive strength, and linear shrinkage. On the one hand, the results show that the major content of the raw materials is silica (SiO2). On the other hand, the results show that the first-stage sintering process had minimal influence on the properties, whereas the second-stage sintering process had a significant influence on the properties of the porous ceramics. With the optimized sintering parameters (temperature, heating rate, and holding time) of the first stage and second stage, we obtained a high-performance porous ceramic product with an apparent porosity up to 51.3%, bulk density up to 1.22 g/cm3, linear shrinkage up to 14.3%, and compressive strength up to 25.1 MPa. Also, the results of the phase composition and microstructure revolution showed sufficient glassy phases and feldspar (Ca, Na) (Si, Al)4O8, which are known to enhance bending strength of ceramics. A comparison of these properties and characteristics with those of standard porous ceramics revealed that the product developed in this study would compete favorably for real applications.
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spelling doaj-art-82a4e7f6488345c5bea2a479b9510b6c2025-02-03T01:21:33ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/37106923710692Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw MaterialsEsam Al-Qadhi0Gaiye Li1Yaxing Ni2College of Mechanics and Materials, Hohai University, Nanjing 211100, ChinaCollege of Mechanics and Materials, Hohai University, Nanjing 211100, ChinaCollege of Mechanics and Materials, Hohai University, Nanjing 211100, ChinaIn this paper, the two-stage sintering process as a promising strategy has been adopted to prepare high-performance porous ceramics with high porosity. Sewage sludge and waste coal ash were used as raw materials and added were starch and CaCO3 as a mixed foaming agent. The chemical composition of the raw materials and mixed foaming agents were analyzed by standard techniques. All mixtures were prepared from fixed solid materials mixed at a ratio of 48 : 32 : 10 : 10 (wt.%) for coal ash, sludge, starch, and CaCO3, respectively, followed by granular molding, aging, sintering and property survey tests. The influence of heating rate, holding time, and heating temperature of the two stages on the characteristics of the as-obtained porous ceramics was deeply investigated. The properties investigated are apparent porosity, bulk density, compressive strength, and linear shrinkage. On the one hand, the results show that the major content of the raw materials is silica (SiO2). On the other hand, the results show that the first-stage sintering process had minimal influence on the properties, whereas the second-stage sintering process had a significant influence on the properties of the porous ceramics. With the optimized sintering parameters (temperature, heating rate, and holding time) of the first stage and second stage, we obtained a high-performance porous ceramic product with an apparent porosity up to 51.3%, bulk density up to 1.22 g/cm3, linear shrinkage up to 14.3%, and compressive strength up to 25.1 MPa. Also, the results of the phase composition and microstructure revolution showed sufficient glassy phases and feldspar (Ca, Na) (Si, Al)4O8, which are known to enhance bending strength of ceramics. A comparison of these properties and characteristics with those of standard porous ceramics revealed that the product developed in this study would compete favorably for real applications.http://dx.doi.org/10.1155/2019/3710692
spellingShingle Esam Al-Qadhi
Gaiye Li
Yaxing Ni
Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
Advances in Materials Science and Engineering
title Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
title_full Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
title_fullStr Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
title_full_unstemmed Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
title_short Influence of a Two-Stage Sintering Process on Characteristics of Porous Ceramics Produced with Sewage Sludge and Coal Ash as Low-Cost Raw Materials
title_sort influence of a two stage sintering process on characteristics of porous ceramics produced with sewage sludge and coal ash as low cost raw materials
url http://dx.doi.org/10.1155/2019/3710692
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AT gaiyeli influenceofatwostagesinteringprocessoncharacteristicsofporousceramicsproducedwithsewagesludgeandcoalashaslowcostrawmaterials
AT yaxingni influenceofatwostagesinteringprocessoncharacteristicsofporousceramicsproducedwithsewagesludgeandcoalashaslowcostrawmaterials