Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials
To effectively utilize coal gangue (CG) with low Al/Si ratio, the thermal activation method was used. The activated CG, as supplementary cementitious materials (SCMs), was added into ordinary Portland cement (OPC) to study its physical properties. The XRD results show that CG undergoes a phase trans...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/21/7268 |
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| author | Xianli Yuan Hong Wu Ping Wang Fen Xu Shuang Ding |
| author_facet | Xianli Yuan Hong Wu Ping Wang Fen Xu Shuang Ding |
| author_sort | Xianli Yuan |
| collection | DOAJ |
| description | To effectively utilize coal gangue (CG) with low Al/Si ratio, the thermal activation method was used. The activated CG, as supplementary cementitious materials (SCMs), was added into ordinary Portland cement (OPC) to study its physical properties. The XRD results show that CG undergoes a phase transition from kaolinite to metakaolinite during activation. The NMR tests reveal that the low polymerization state Q<sub>3</sub> is continuously broadened, and the Al coordination gradually changes from Al <sup>VI</sup> to Al <sup>V</sup> and Al <sup>IV</sup>. The CG particles are scale-like and glassy with a loose structure. By mixing the activated CG (under 800 °C) with cement (mass ratio = 3:7), the water demand of normal consistency increases by 7.2% and the initial and final setting times extend by 67 min and 81 min, respectively. The rough surface and loose structure of activated CG are the main factors contributing to the higher water demand of normal consistency. The micro-aggregate effect of the activated CG reduces the contact rate between the cement particles and water, and the interparticles, thus slowing down the process of hydration reaction, and leading to longer setting times. |
| first_indexed | 2024-03-09T18:49:21Z |
| format | Article |
| id | doaj.art-d927f241aecf4db28be271dabe1ce7cf |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T18:49:21Z |
| publishDate | 2022-10-01 |
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| series | Molecules |
| spelling | doaj.art-d927f241aecf4db28be271dabe1ce7cf2023-11-24T06:01:23ZengMDPI AGMolecules1420-30492022-10-012721726810.3390/molecules27217268Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious MaterialsXianli Yuan0Hong Wu1Ping Wang2Fen Xu3Shuang Ding4College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, ChinaSchool of Chemical and Materials Engineering, Liupanshui Normal University, Liupanshui 553004, ChinaSchool of Chemical and Materials Engineering, Liupanshui Normal University, Liupanshui 553004, ChinaCollege of Environmental and Chemical Engineering, Dalian University, Dalian 116622, ChinaCollege of Environmental and Chemical Engineering, Dalian University, Dalian 116622, ChinaTo effectively utilize coal gangue (CG) with low Al/Si ratio, the thermal activation method was used. The activated CG, as supplementary cementitious materials (SCMs), was added into ordinary Portland cement (OPC) to study its physical properties. The XRD results show that CG undergoes a phase transition from kaolinite to metakaolinite during activation. The NMR tests reveal that the low polymerization state Q<sub>3</sub> is continuously broadened, and the Al coordination gradually changes from Al <sup>VI</sup> to Al <sup>V</sup> and Al <sup>IV</sup>. The CG particles are scale-like and glassy with a loose structure. By mixing the activated CG (under 800 °C) with cement (mass ratio = 3:7), the water demand of normal consistency increases by 7.2% and the initial and final setting times extend by 67 min and 81 min, respectively. The rough surface and loose structure of activated CG are the main factors contributing to the higher water demand of normal consistency. The micro-aggregate effect of the activated CG reduces the contact rate between the cement particles and water, and the interparticles, thus slowing down the process of hydration reaction, and leading to longer setting times.https://www.mdpi.com/1420-3049/27/21/7268coal ganguelow Al/Si ratiothermal activationsupplementary cementitious materialphysical propertiespozzolanic reactivity |
| spellingShingle | Xianli Yuan Hong Wu Ping Wang Fen Xu Shuang Ding Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials Molecules coal gangue low Al/Si ratio thermal activation supplementary cementitious material physical properties pozzolanic reactivity |
| title | Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials |
| title_full | Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials |
| title_fullStr | Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials |
| title_full_unstemmed | Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials |
| title_short | Thermal Activation of Coal Gangue with Low Al/Si Ratio as Supplementary Cementitious Materials |
| title_sort | thermal activation of coal gangue with low al si ratio as supplementary cementitious materials |
| topic | coal gangue low Al/Si ratio thermal activation supplementary cementitious material physical properties pozzolanic reactivity |
| url | https://www.mdpi.com/1420-3049/27/21/7268 |
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