Micromorphology and physicochemical properties of hydrophobic blasting dust in iron mines

Abstract

The micromorphology and physicochemical properties of hydrophobic blasting dust (HBD) from an iron mine were comprehensively analyzed by laser particle size analysis (LPSA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that the HBD particles can be classified into three types based on their particle size (PS): larger particles (PS > 10 µm), medium particles (1 µm ≤ PS ≤ 10 µm), and nanoparticles (PS > 1 µm). The cumulative volume of respirable dust (PS > 10 µm) was 84.45%. In addition, three shapes of HBD were observed by SEM: prism, flake, and bulk. In particular, the small particles were mostly flaky, with a greater possibility of being inhaled. Furthermore, the body and surface chemical compounds of HBD were determined by XRD and XPS, respectively. Ammonium adipate (C6H16N2O4) was the only organic compound in the body of HBD, but its mass fraction was only 13.4%. However, the content of organic C on the surface of HBD was 85.35%. This study demonstrated that the small-particle size and large amount of organic matter on the surface of HBD are the main reasons for its hydrophobicity, which can provide important guidance for controlling respirable dust in iron mines.