Fabrication of ceramic monoliths from diatomaceous earth: effects of calcination temperature on silica phase transformation

Autor: Reka Arianit A., Kosanović Darko, Ademi Egzon, Aggrey Patrick, Berisha Avni, Pavlovski Blagoj, Jovanovski Gligor, Rexhepi Besnik, Jashari Ahmed, Makreski Petre
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Science of Sintering, Vol 54, Iss 4, Pp 495-506 (2022)
Druh dokumentu: article
ISSN: 0350-820X
1820-7413
DOI: 10.2298/SOS2204495R
Popis: The raw diatomaceous earth from the vicinity of Bitola (North Macedonia) showed low bulk density (0.61-0.69 g/cm3), high-water absorption (75-81%) and porosity (66- 72%). The chemical composition was determined with ICP-MS, revealing the following results for the diatomaceous earth: SiO2 (63.69 wt%), Al2O3 (11.79 wt%), Fe2O3 (5.95 wt%), MnO (0.15 wt%), TiO2 (0.65 wt%), CaO (1.51 wt%), MgO (2.24 wt%), P2O5 (0.13 wt%), K2O (1.64 wt%), Na2O (0.93 wt%), LOI (11.21 wt%). XRPD data of the examined sample of clayey diatomite mainly depicted crystalline behavior with a small presence of amorphous phase. The crystalline mineral phases mainly comprise: silica (quartz), feldspars (plagioclase), mica (muscovite), chlorites and dolomite. SEM and TEM results show cased presence of micro- and nanostructures with pores ranging from 250 to 600 nm. The clayey diatomite was sintered at three temperatures (900, 1000 and 1100ºC) for a period of 1 h. XRPD of the sintered samples at 1100ºC showed certain thermal stability and formation of new phases (mullite and tridymite) that makes the analyzed diatomaceous earth suitable for production of various types of ceramic, construction and thermal insulating materials.
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