Study of ground and unground leached vermiculite II. Thermal behaviour of ground acid-treated vermiculite

0358368 - ÚACH 2012 RIV NL eng J - Článek v odborném periodiku
Perez-Rodriguez, J. L. - Maqueda, C. - Murafa, Nataliya - Šubrt, Jan - Balek, Vladimír - Pulišová, Petra - Lančok, Adriana
Study of ground and unground leached vermiculite II. Thermal behaviour of ground acid-treated vermiculite.
Applied Clay Science. Roč. 51, č. 3 (2011), s. 274-282. ISSN 0169-1317. E-ISSN 1872-9053
Grant CEP: GA MŠMT(CZ) LC523
Výzkumný záměr: CEZ:AV0Z40320502
Klíčová slova: vermiculite * annealing * amorphous silica
Kód oboru RIV: CA - Anorganická chemie
Impakt faktor: 2.474, rok: 2011

In this study, we examined the annealing effect on the material obtained after acid treatment of ground vermiculite which constituted amorphous silica and β-FeOOH. The XRD patterns of the starting sample measured at temperatures from 30 to 1200 °C showed that the crystalline phase was present until ~ 300 °C; whereas the sample heated between 300 and 800 °C was practically amorphous. This is in agreement with previous observations that β-FeOOH decomposes to amorphous or poorly crystalline phase, β-Fe2O3, and transforms only slowly to crystalline α-Fe2O3. At 850 °C the sample showed the first signs of a crystalline phase which was fully developed at 1050 °C. The XRD, HRTEM and Mössbauer spectroscopy showed, after heating at 1050 °C, the presence of crystalline phase, consisting of quartz, cristobalite, α-Fe2O3 and ε-Fe2O3.
Trvalý link: http://hdl.handle.net/11104/0196435