Abstract
The objective of this work is the study the crystal structure and elemental content of braunite-hematite and braunite-psilomelane oxide manganese ores y means of X-ray diffractometry (XRD), Energy Dispersion X-ray (EDX) analysis, and X-Ray fluorescent (XRF) analysis. It was found that heat treatments at 600, 800, and 1000 °C promote the phase transitions of the manganese ores to the formation of thermostable phases hausmannite and bixbyite without change in the metallic composition. The homogeneity of the structure increases with increasing temperature, which is expressed in the decreasing of the Mn content in the EDX spectra after sintering above 800 °C as well as in a decrease of the phase number to only two phases: bixbyite and quartz. Remarkably, the hausmannite phase is obtained in the fraction of 61% after sintering the braunite-hematite ore sample at 1000 °C for 4 h. Since hausmannite is widely used to produce building materials, electrodes, catalysts, and other materials, these results are promising for developing technologies for obtaining new products based on phases of manganese minerals at high temperatures.