Difratometria e fluorescência de raios X aplicadas na caracterização e identificação de minerais

Abstract

Eight samples from the didactic collection of minerals of the Geology Department, Federal University of Rio Grande do Norte were selected for mineralogical characterization studies. The physical properties of the studied minerals were determined from the samples through simple analytical tests, whereas their crystalline structure and chemical compositions were obtained by X ray diffraction (XRD) and fluorescence (XRF) analysis, respectively. The integrated results allowed the identification of the studied minerals as follows: columbite-(Mn) [(Mn, Fe)Nb2,O6], tantalite [(Fe, Mn)Ta2O6] and manganotapiolite [(Mn, Fe)(Ta, Nb)2 O6]; calcite (CaCO3); rhodonite [(MnSiO3] and in other phases amphiboles as: manganogrunerite (Ca0,1 Fe3,937 H2 Mg1,25 Mn 1,901 O24 Si 7,812) and cummingtonite (Fe, Mg)7 Si8O22(OH)2; uraninite (UO2) with other mineral phases as: potassium feldspar (KAlSi3O8), iriginite [H2(UO2)(MoO4)2 . 3H2O] and yingjiangite (K2, Ca)(UO2)7(PO4)4(OH)6 . 6H2O; kyanite (Al2SiO5), tremolite-actionolite [Ca2(Fe,Mg)5Si8O22(OH)2]; monazite-(Ce) [(Ce,La,Th)PO4]; and a mineral aggregate with yingjiangite [K2Ca(UO2)7(PO4)4(OH)6.6H2O], phosphuranylite [Ca(UO2)[(UO2)3(OH)2(PO4)2]2.12H2O], autunite [Ca(UO2)2(PO4)2•10-12(H2O)] and metauranocircite [Ba(UO2)2(PO4)2•6-8(H2O)].