Characterization of micaceous minerals occurring in phosphate ores in Brazil: emphasis on the interstratified phyllosilicates

Abstract

Micaceous minerals were characterized in three phosphatic ores from mines in Western Minas Gerais State, Brazil, all having complex chemical and mineralogical compositions, with emphasis on interstratified phyllosilicates. Knowledge of the relationship between the physical and chemical characteristics of the phyllosilicates contributed to a better understanding of the physicochemical processes in the mineral processing stages. Characterization of the minerals was carried out mainly by X-ray diffractometry (XRD), which allowed identifying vermiculite and three interstratified phyllosilicate phases. These minerals presented regular stratification of the unit cell, with different percentages of vermiculite and mica. Complementary studies by scanning electron microscopy (SEM) with EDS microanalysis, thermogravimetry and chemical analysis confirmed the identifications by XRD.