Probing the effect of particle imperfections on the sliming of siderite in carbonate-bearing iron ore

Abstract

The sliming properties of siderite contained in carbonate-bearing iron ore have an unavoidable, negative impact on the reverse flotation of hematite during the beneficiation process. This leads to the ineffective beneficiation of carbonate-bearing iron ore. The main purpose of this study was to reveal the effect of particle imperfections in siderite and hematite on the inherent sliming mechanism, from the perspectives of local defects in the crystal structures and the pre-existing micropores present in these particles. To this end, an X-ray microscope (XRM) was used to characterize the mesostructure of milled siderite and hematite, revealing their particle size and the pre-existing micropores present in these minerals. Additionally, the microstructures of vacancy defects in the crystals were determined with the aid of density functional theory (DFT). XRM results demonstrated that siderite particles contain a greater density of pre-existing micropores than hematite particles, increasing the sliming properties of siderite when it is milled simultaneously with hematite. DFT calculations suggested that siderite crystals were more susceptible to O-vacancy defects, which contributes to the number of micropores in siderite particles. This study provides an insight into the relationship between the particle structure and sliming properties of siderite and hematite, thereby paving the way for improvements in the beneficiation process of carbonate-bearing iron ore.