Uso de um hidrociclone para purificação de esmectitas.

Abstract

The national bentonite clays presents contaminant elements that interfere the acting of this clays for industrial uses, for example, contamination the drilling fluids with alteration of the its viscosity, interference the intercalation of organic molecules in the organoclays formation for the use in clay/polymer nanocomposites, staying in the form of agglomerates causing of decrease of mechanical properties, as well as causing the degradation of the polymer matrix due to presence of the iron with contaminant elements. The present work has for objective to study the purification of bentonite clays using a hydrocyclone, to determine the best geometry of the hydrocyclone to obtain the most effective process of purification of the studied clays. For the hydrocyclone purification process was used RWK 42L of Netzsch AKW, with internal diameter of 20mm, varying the dimensions of its components: three underflow pipe and two vortex. The dispersions were used with concentration of 4% of the bentonita clays: Chocolate in the natural state and Brasgel PA commercial, for at the most 4 purification cycles. Physical-mineralogical characterizations were accomplished of the dispersions of initial clay and of the overflow and underflow samples: chemical analysis by XED, XRD, laser granulometric analysis, final concentration determination and rheological properties of the samples. The hydrocyclone purification system is shown effective for retreat of the gross fractions, mainly particles with diameters superiors to the strip limit of separation of the equipment. The best configuration for clay purification of the Chocolate consists of the vortex of 5mm and underflow pipe of 4mm, while for the Brasgel PA clay the best configuration was obtained for the vórtex of 6mm and underflow pipe of 4mm.