Estudo comparativo da composição química e as variedades de cores de argilas bentonita da cidade de Boa Vista-PB.

Abstract

The Bentonitic clay is widely used in many areas of the industry, such as drilling mud for petroleum and water perforations, steel industries, pelotization of iron ore, chemical and pharmaceutical industry, among others. Paraiba concentrates about 60% of the national reserves, the raw Bentonite produced in 1999 represented 90% of the brazilian production and the benefited one 94,2%. In the processing segment, where beyond the simple benefaction of desintegration, homogenation and drying, the ativation is carried out, by the addition of sodium carbonate transforming the bentonite of calcic nature to sodic. The Bentonites of Boa Vista PB, form small deposits distributed in a distance of 10 km. The country rocks are the basaltic flow of the Tertiary in the east and the granites and gneisses of the Pre-Cambrian in the west. The Bentonite is characterized by the predominance of clay minerals smectite, ilite and kaolinite. In this research samples of Bentonites of the Boa Vista region of various colors such as white, green, chocolate, bofe, red, yellow were analyzed with the objective of identifying and characterizing the chemical composition and mineralogy of the clay classified based on colors. The methodology used in this work included collection of samples from the bentonite processing companies and from the deposits, chemical composition analysis, analysis and interpretation of the data based on the colors of the bentonite. There is a perfect correlation between the colors and the chemical and mineralogical camposition of the bentonite. The technical properties of the clay depends on the composition and mineralogy. Classification of the bentonite based on colors for industrial uses and treatment is valid because in this work it was noted that the chemical and mineralogical composition of the clay tend to be different in function of the colors found in the bentonite deposits of the Boa Vista region.