Study of ground and unground leached vermiculite
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 °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 (β-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. The leached vermiculite residue also contained Cl- and a small amount of Ti4+, which were accumulated into the akaganeite microcrystals.
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2009
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dig-irnas-es-10261-635692016-02-17T12:03:14Z Study of ground and unground leached vermiculite Maqueda Porras, Celia Pérez Rodríguez, José Luis Subrt, J. Murafa, N. 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 °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 (β-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. The leached vermiculite residue also contained Cl- and a small amount of Ti4+, which were accumulated into the akaganeite microcrystals. Peer Reviewed 2012-12-23T12:13:44Z 2012-12-23T12:13:44Z 2009 2012-12-23T12:13:44Z artículo http://purl.org/coar/resource_type/c_6501 doi: 10.1016/j.clay.2009.01.019 issn: 0169-1317 Applied Clay Science 44(1-2): 178-184 (2009) http://hdl.handle.net/10261/63569 10.1016/j.clay.2009.01.019 en none Elsevier |
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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 °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 (β-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. The leached vermiculite residue also contained Cl- and a small amount of Ti4+, which were accumulated into the akaganeite microcrystals. |
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artículo |
author |
Maqueda Porras, Celia Pérez Rodríguez, José Luis Subrt, J. Murafa, N. |
spellingShingle |
Maqueda Porras, Celia Pérez Rodríguez, José Luis Subrt, J. Murafa, N. Study of ground and unground leached vermiculite |
author_facet |
Maqueda Porras, Celia Pérez Rodríguez, José Luis Subrt, J. Murafa, N. |
author_sort |
Maqueda Porras, Celia |
title |
Study of ground and unground leached vermiculite |
title_short |
Study of ground and unground leached vermiculite |
title_full |
Study of ground and unground leached vermiculite |
title_fullStr |
Study of ground and unground leached vermiculite |
title_full_unstemmed |
Study of ground and unground leached vermiculite |
title_sort |
study of ground and unground leached vermiculite |
publisher |
Elsevier |
publishDate |
2009 |
url |
http://hdl.handle.net/10261/63569 |
work_keys_str_mv |
AT maquedaporrascelia studyofgroundandungroundleachedvermiculite AT perezrodriguezjoseluis studyofgroundandungroundleachedvermiculite AT subrtj studyofgroundandungroundleachedvermiculite AT murafan studyofgroundandungroundleachedvermiculite |
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1777664489767829504 |