Thermal behavior of a mineral mixture of sepiolite and dolomite

Yener N., Onal M., Ustunisik G., Sarikaya Y.

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol.88, no.3, pp.813-817, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 88 Issue: 3
  • Publication Date: 2007
  • Doi Number: 10.1007/s10973-005-7459-0
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.813-817
  • Keywords: dehydration, dehydroxylation, sepiolite, surface area, thermal analysis, X-ray diffraction, CATALYTIC ACTIVITY, HYDROCHLORIC-ACID, BOUND WATER, TURKEY, PALYGORSKITE, DEHYDRATION, ESKISEHIR, CLAYS, BASIN, ULTRAFILTRATION
  • Dokuz Eylül University Affiliated: Yes


An industrial raw material taken from Beypazan (Ankara, Turkey) region was heated at different temperatures in the 100-1100 degrees C interval for 2 h. The volumetric percentage of particles having diameter below 2 mu m in an aqueous suspension of the material held 24 h were determined as 85% by the particle size distribution analysis. The mineralogical composition of the material was obtained as mass% of 81% sepiolite, 15% dolomite, and 4% interparticle water by using the X-ray diffraction (XRD) and thermal analysis (TG, DTA) data. The temperature ranges were determined for the dehydrations of the interparticle water and the zeolitic water as 25-340 degrees C, for the dehydration of the bound water as 340-580 degrees C, and for the dehydroxylation of the hydroxyls as 800-833 degrees C in the sepiolite. The zig-zag changes in the specific surface area (S/m(2) g(-1)) and specific micro- and mesopore volume (V/cm(3) g) with the temperature increases were discussed according to the dehydrations and dehydroxylation of the sepiolite.