A intercalação de cátions metálicos e seu efeito sobre as propriedades de esfoliação e inchamento da vermiculita de Santa Luzia-PB.

Abstract

The present work had as the objective to study the effect of intercalation of the metallic cátions: Mg2+, Ca2+, Al3+ e Na+, on the clorets form and only in the Na* case on the nitrate form, upon properties of the thermal exfoliation and swelling in water, in vermiculite samples of the Santa Luzia - PB. The parameters evaluated were: (a) type of metallic cation; (b) vermiculite granulometry; (c) concentration of intercalation solution and (d) type of anion associated on the metallic cation. Initially a mineralogical and chemistry characterization was make on the vermiculite concentrate, across techniques of scanning electronic microscopy (SEM), diffraction of rayX (DRX), fluorescence of rayX (FRX), differential thermal analyses and thermo gravimetric (DTA-TG) and cationic exchange capacity (CEC). The results of the exfoliation indicated which the vermiculite intercalation with clorets decrease sensiblely the vermiculite exfoliation capacity, in relation at natural vermiculite (without treatment). This reduction was 50 % with Al3" and 10 % with Mg2*. However, the treatment with sodium nitrate increased in 15 % the vermiculite exfoliation capacity. For swelling was observed which the general mode, the intercalation with clorets and with NaN03 promoted the swelling in water of the vermiculites and this rate of swelling changed with concentration of intercalation solution, with vermiculite granulometry, with type of intercalater cation and type of anion associated to him. The cation that promoted the biggest swelling was the Mg2" following in decreasing order by Ca2+, Al3+ and Na+, was had variations in this order in relation at granulometry and concentration of intercalation solution employed. The intercalation with sodium nitrate promoted best swelling rates in relation rates obtained with sodium cloret, for ali cases studied.