In order to improve manganese-iron alloy production processes, an important Brazilian manganese ore typology, placed in Carajás, PA, was characterized. A representative sample was obtained from mine. The particle size determination was performed by screening, followed by chemical analysis using plasma spectrometry (ICP-AES). The physical properties studied included density, surface area and porosity measurements (BET). The mineral constituents was identified and quantified by X-ray diffraction. A termogravimetrical study was done in order to verify the thermal stability of major mineral constituents in the air. It was observed that 19.3% of studied typology was below 6.3mm. The manganese, silica and phosphorus contents were 52.63%, 1.92% and 0.17%, respectively. The oxides identified were cryptomelane, todorokite and pyrolusite. The other constituents were goethite, quartz, gibbsite, and kaolinite. According to the thermal study, the cryptomelane and pyrolusite start their decomposition in the air, at approximately 600ºC. At around 950ºC, Mn2O3 decomposition and Mn3O4 growth were observed.
Manganese ore; typological characterization; thermal decomposition
