On-line version ISSN 1852-7744
CASTILLO, Luciana et al. Separación y purificación de fibras de sepiolita: contribución al procesamiento de arcillas especiales para uso industrial. Geoacta [online]. 2011, vol.36, n.2, pp. 113-127. ISSN 1852-7744.
Sepiolite is a clay minerals with greater surface area, allowing the adsorption of water, polar liquids, ions and other molecules. This particular hydrophilicity is due to the presence of active adsorption centers on the surface of sepiolite. Taking into account this mineral is used as absorbent and as reinforcement in plastics, the highest length/diameter ratio is needed in order to maximize properties. Then, fiber disaggregation would increase its application field and the added value of this untapped mineral in Argentina. In this work, different methods as liofilization, sonication and acid leaching are explored, focusing in the optimization of disaggregation and purification of the fibers. The comparative analysis was made through the sepiolite characterization before and after each treatment by electronic and optical microscopy, x ray diffraction, infrared spectroscopy and thermal analysis. The results obtained from the acid leaching describe it as the better treatment respect to the sepiolite purification due to carbonates elimination. The sonication allows a particular disaggregation, leading to a gel structure development, product of the high entanglement of nanofibers which retain water molecules inside the network. In the case of the liofilization, it produces a substantial morphological variation of the fibers respect to their disaggregation. This method is the best for conserving the initial length of the fibers. These results allow inferring that the sepiolite can be easily processed and be used in different industries in our country with a high added value, replacing its importation.
Keywords : Sepiolite; Disaggregation and purification; Industrial application.