Preparation and thermal properties of commercial vermiculite bonded with potassium silicate
| Autor: | Johan Frederik Schou Christensen, N.T. Jørgensen, S. Gustafson, L.A. Lindbjerg, Rasmus Rosenlund Petersen, Yuanzheng Yue |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Vermiculite 02 engineering and technology 01 natural sciences law.invention chemistry.chemical_compound Differential scanning calorimetry law Exfoliation Physical and Theoretical Chemistry Crystallization Shrinkage Instrumentation Potassium silicate Moisture Dehydration Crystallisation 021001 nanoscience & nanotechnology Condensed Matter Physics Exfoliation joint 010406 physical chemistry 0104 chemical sciences Thermogravimetry chemistry Chemical engineering 0210 nano-technology Clay minerals |
| Zdroj: | Petersen, R R, Christensen, J F S, Jørgensen, N T, Gustafson, S, Lindbjerg, L A & Yue, Y 2021, ' Preparation and thermal properties of commercial vermiculite bonded with potassium silicate ', Thermochimica Acta, vol. 699, 178926 . https://doi.org/10.1016/j.tca.2021.178926 |
| Popis: | Expanded vermiculite bonded with potassium silicate finds use as high-temperature insulation boards. The thermal properties of the vermiculite boards are critical for their applications and expected lifetime. This work reports on the processing and thermal properties of vermiculite boards (400–600 kg m−3) prepared from three different commercial vermiculite sources. Commercial vermiculite is first expanded through flash-heating, then mixed with potassium silicate and then finally pressed to boards. The untreated- and expanded vermiculite and the boards are studied with X-ray diffraction, differential scanning calorimetry, thermogravimetry, heating microscope and electron microscope. The expansion process affects the ability of the expanded vermiculite to reabsorb moisture and the ability is dependent on vermiculite source. The vermiculite boards undergoes several physical-chemical transitions at elevated temperatures. Water from both clay minerals and binder is lost at 2SiO4) and leucite (KAlSi2O6) crystallise subsequently. At 1200–1420 °C, the leucite melts and the boards shrink again. The crystallisation- and melting temperatures depend on the vermiculite source. These findings provide practical guidelines for processing vermiculite into lightweight boards. |
| Databáze: | OpenAIRE |
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