Počet záznamů: 1

Study of ground and unground leached vermiculite

  1. 1.
    0340225 - UACH-T 2010 RIV NL eng J - Článek v odborném periodiku
    Maqueda, C. - Perez-Rodriguez, J. L. - Šubrt, Jan - Murafa, Nataliya
    Study of ground and unground leached vermiculite.
    Applied Clay Science. Roč. 44, 1-2 (2009), s. 178-184 ISSN 0169-1317
    Grant ostatní: CICYT(ES) AGL-2005-0164
    Výzkumný záměr: CEZ:AV0Z40320502
    Klíčová slova: vermiculite * amorphous silica * acid leaching
    Kód oboru RIV: CA - Anorganická chemie
    Impakt faktor: 2.784, rok: 2009

    Grinding of clays modifies their surfaces and can significantly affect their leaching behaviour. The acid reaction of vermiculite from Santa Olalla (Huelva, Spain) with HCl at various concentrations was affected by grinding and acid concentration. The acid leaching of ground vermiculite for 3 min with 1 M HCl solution at 80 degrees C for 24 h removed MgO and Al2O3 almost completely, leaving a residue containing SiO2 and Fe2O3. X-ray diffraction analysis showed the presence of akaganeite (beta-FeOOH) and an amorphous phase (silica). Porosity studies showed a very high specific surface area for ground samples compared with unground vermiculite samples, attributed to the presence of iron in the residue coming from structural iron. High resolution transmission electron microscopy (HRTEM) confirmed the presence of iron oxyhydroxides embedded in the silica material. The particle morphology of the iron oxides corresponded well to akaganeite microcrystals precipitated from solution.
    Trvalý link: http://hdl.handle.net/11104/0183512