Fabrication of Ceramic Monoliths from Diatomaceous Earth: Effects of Calcination Temperature on Silica Phase Transformation

  • Arianit A. Reka Faculty of Natural Sciences and Mathematics, University of Tetovo; Department of Materials Science and Engineering, Missouri University of Science and Technology; Nano Alb-Unit of Albanian Nanoscience and Nanotechnology
  • Darko Kosanović Department of Materials Science and Engineering, Missouri University of Science and Technology; Institute of Technical Sciences of the Serbian Academy of Sciences and Arts
  • Egzon Ademi Faculty of Natural Sciences and Mathematics, University of Tetovo
  • Patrick Aggrey Hierarchically Structured Materials, Center for Energy Science and Technology, Skolkovo Institute of Science and Technology
  • Avni Berisha Nano Alb-Unit of Albanian Nanoscience and Nanotechnology
  • Blagoj Pavlovski Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University in Skopje
  • Gligor Jovanovski Faculty of Technology and Metallurgy, Ss. Cyril and Methodius University
  • Besnik Rexhepi Faculty of Natural Sciences and Mathematics, University of Tetovo
  • Ahmed Jashari Faculty of Natural Sciences and Mathematics, University of Tetovo
  • Petre Makreski Macedonian Academy of Sciences and Arts, Research Center for Environment and Materials

Abstract

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.

Published
2022-12-10
Section
Articles