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Study of ground and unground leached vermiculite
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SYSNO ASEP 0340225 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Study of ground and unground leached vermiculite Author(s) Maqueda, C. (ES)
Perez-Rodriguez, J. L. (ES)
Šubrt, Jan (UACH-T) SAI, RID
Murafa, Nataliya (UACH-T) RID, SAISource Title Applied Clay Science. - : Elsevier - ISSN 0169-1317
Roč. 44, 1-2 (2009), s. 178-184Number of pages 7 s. Language eng - English Country NL - Netherlands Keywords vermiculite ; amorphous silica ; acid leaching Subject RIV CA - Inorganic Chemistry CEZ AV0Z40320502 - UACH-T (2005-2011) UT WOS 000265327000025 EID SCOPUS 62649136931 DOI 10.1016/j.clay.2009.01.019 Annotation 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. Workplace Institute of Inorganic Chemistry Contact Jana Kroneislová, krone@iic.cas.cz, Tel.: 311 236 931 Year of Publishing 2010
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