Comportamento térmico e evolução das fases de óxidos de Mn com estrutura hollandita da região Amazônica ; Thermal behavior and evolution of the Mn oxides phases with hollandite structure from Amazon region

The tunnel-structure manganese oxide minerals, hollandite (Apuí, Amazonas state, Brazil, area in prospection) and cryptomelane (Urucum, Mato do Sul Grosso state, Brazil) were isolated and characterized chemical, mineralogical, thermal and morphologically. The following techniques were employed: scanning electron microscopy-EDS, thermal analysis (DTA-TG), X-ray diffraction with continuous-heating. The empirical formula, were calculated on the basis 16 oxygen gave as (Ba0,18K0,12Ca0,02Pb0,04)0,76(Mn6,34Al0,61Si0,25Fe0,24Ti0,08) 7,54O160,4H2O for hollandite and (K0,9Na0,04Ca0,03Sr0,04) 1,04 (Mn7,... Mehr ...