Reutilização de ácido sulfúrico no tratamento químico de Vermiculita.

Abstract

Clay minerals belong to the lamellar phylosilicate family, which can be defined as silicates containing two-dimensional sheets. The crystals consist of tetrahedral coverslips and octahedral, usually of the 2: 1 type. The fundamental units are Si (O, OH) 4, constituting the tetrahedral and M (O, OH) 6 constituting the octahedral network, with M = Mg 2+, Al 3+, Fe 2+ and Fe 3+. At Clays are natural materials that have aroused great interest due to their characteristics. textures and the possibility of modification reactions for the optimization of properties, such as the case of acid leaching. The present study evaluated solids obtained from chemical treatment vermiculite clay, by the acid leaching process with reuse of the leaching acid, in order to promote positive economic and environmental aspects to synthesis. In this process, Clean, monoionic clay was treated with H 2 SO 4 acid solution with a concentration of 2.0 mol.dm -3, 1:10 (clay, acid) at reflux at a temperature of 353 K to give The first solid. After the procedure, the acid used was collected as much as possible (~ 30 cm 3), its volume was completed to 50 cm 3, thus being reused in the repetition of the leaching procedure with a new sample. This acid reuse process was repeated seven times to assess acid leaching capacity, yielding a total of 8 solids, sequentially: VA1, VA2, VA3, VA4, VA5, VA6, VA7, VA8, who underwent chemical characterization. Results obtained from X-ray fluorescence, X-ray diffraction X-ray and infrared spectroscopy demonstrated that the synthesis with reuse of the acid is effective, obtaining materials with different composition and structure crystalline, with amorphous characteristics and new sites for adsorption and catalysis.