Modificações de propriedades reológicas de esmectíticas sódicas.

Abstract

Previous work has shown that sodium smectites, industrialized in the State of Paraíba, present inadequate rheology in the form of a very rigid gel called flocculated gel with very high viscosity and viscosity very low plastic. These dispersions result from electrical "face-to-edge" interactions between the clay particles being formed a house of cards that occupies the entire volume of the dispersion. In order to know and correct this problem, deflocculation curves were obtained to determine the maximum flocculation point. With the dispersions at the maximum deflocculation point, treatments with industrial additives in order to obtain a suitable rheology in order to meet the specifications of Petrobras, and also the carbonate and bicarbonate contents in the dispersions. In order to better study the phenomena involved, a statistical treatment was done in the form of simple linear regressions by least squares method between the additive contents and the rheological characteristics, as well as the carbonate and bicarbonate contents. An analysis of the results allowed us to conclude: a) that the existence of flocculated gel dispersions is due, among other factors, to the treatment with high levels of sodium carbonate; b) that the additives make possible corrections in the rheology and the most efficient results were obtained with the carboxymethylcellulose (CMC) and finally c) the existence of interdependence between the contents of the additives and the properties studied.