Investigation of transformations of low-grade manganese ore during the roasting process

Abstract

The transformations of low-grade manganese ore were investigated during roasting in the air at different temperatures up to 1200°C. The transformations were followed up by XRD and TGA-DTA. Moreover, the morphology and magnetic properties were determined by SEM and VSM. It was observed that MnO 2 transformed to the lower oxide Mn 5 O 8 at 500°C and then to bixbyite (Mn 2 O 3 ) at 600°C. Finally, the bixbyite decomposed to hausmannite (Mn 3 O 4 ) at 800°C. Increasing the roasting temperature to 900°C induced a reaction between hematite and hausmannite and led to the formation of a small amount of solid solution of the ferrite spinel MnFe 2 O 4 . Further increase in temperature to 1000°C led to the formation of a solid solution of braunite (Mn 7 SiO 12 ) which decomposed to rhodonite (MnSiO 3 ) at 1200°C. The magnetic susceptibility of the original ore gradually increased with the roasting temperature, from 0.119 × 10 −3 at ambient temperature to a maximum value of 80 × 10 −3 at 1200°C.

Processing of low-quality manganese-containing raw materials to obtain pellets for production ferromanganese alloys. Review

“…Исследованы превращения низкосортной марганцевой руды при обжиге на воздухе при температурах до 1200℃ с применением методов XRD и TGA-DTA [24]. Выявлено, что MnO2 превращается в низший оксид Mn5O8 при 500℃, а затем в биксбиит (Mn2O3) при 600℃.…”