CARACTERIZAÇÃO TECNOLÓGICA DAS ARGILAS DA PENÍNSULA DE SANTA ELENA, EQUADOR: VIABILIDADE DE SUAS UTILIZAÇÕES INDUSTRIAIS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Clays of the Santa Elena Peninsula located to the southwest of the coast of Ecuador have been studied in order to identify its main physical, chemical and mineralogical characteristics, as well as the main mineral contained in these clays. One hundred eighty eight points were searched and forty and two samples were collected, being representative of the six main clay deposits identified in the Peninsula. These clays belong to the units from the Ancón Group (Middle and Upper Eocene), Tosagua (Upper Oligocene and Middle Miocene) and Progreso (Middle and Upper Miocene) Formations. They were originated from the ashes of the Andean volcanism that had been deposited in a marine environment. Analyses by x-ray diffraction, x-ray spectroscopy, differential and gravimetric thermal analyses, infrared spectroscopy, granulometric analyses, surface area, density, porosity, morphologic study by scanning electron microscopy and cationic exchange capacity had allowed to identify calcic montmorillonite as the main clay mineral as they were utilized in the trials of acid activation, pilarisation, as well as its applications in the discoloring of soybean oil. Bentonitic clays are sufficiently used in adsorption processes after treatments by acid activation, however, after pillarization are also being used for this objective. In this context, two samples of the Tosagua Formation, labelled FT1 and FT8, that had presented greater content in montmorillonite and in the clay fraction (particles <2 μm) had been submitted to the treatments of activation with HCl and H2SO4 and pillarization with Al13 to subsequently be used in the bleaching of soybean oil. The activation with H2SO4 was more effective in increasing the porosity and surface area of the samples, than with HCl. The pillarization of the two natural samples did not show the results expected, in that the pillared samples had been submitted activation with H2SO4. The acid activation after pillarization also showed an increase of the porosity and surface area. In the bleaching of soybean oil, the acid-activated samples with H2SO4 after pillarization with Al13 have shown efficiency up to 92 % in the adsorption of β-carotene and up to 88 % in the adsorption of chlorophyll. These values surpassed the values obtained with a commercial acid-activated clay. The samples activated with this acid were also efficient, with results close to the ones for the commercial clay Result of the mineralogical and technological characterization of the Ecuadorian clay affirmed that this clay can be optimized with treatments of acid-activation for its application in industrial processes of vegetal oil refining.

ASSUNTO(S)

1. considerações gerais. 2. materiais e métodos geologia. 3. abentonita: conceito e aplicações tecnológicas. 4. caracterização mineralógica e tecnológica. caracterização mineralógica das argilas da engenharias

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