Micro-characterization of Dust and Materials of Dust Origin at a Cement Industry Located in Bangladesh

Abstract

Industrial dust generation from material processing is an uninterrupted phenomenon, hence analyzing materials of dust origin with dust particles is important to comprehend the entire scenario of occupational health exposure (OHE). In this study, we investigated the morphological, elemental, and mineralogical characteristics of engendered dust and materials of dust origin in the cement industry (CI) in Bangladesh. The dust samples were accumulated from dust collectors and the internal roadways of the CI to understand the nature of atmospheric dust of the CI. All the materials that could potentially be the sources of the dust of the CI were collected, including clinker, gypsum, limestone, fly ash, slag, and two types of cement products. Scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS), x-ray powder diffraction (XRD), and fourier-transform infrared spectroscopy (FTIR) were performed for the characterization. SEM micrographs showed the presence of fine (particles ≤ PM2.5) and ultra-fine (particles ≤ PM0.1) particles with diverse morphology in the studied samples. Ca, Si, Al, Mg, Fe, K, Na, Mo, and Ti were found as existing metallic elements in samples through the EDS technique. Several minerals of silicate, oxide, carbonate, and sulfate were detected with major crystalline phases of Portland cement by SEM-EDS, XRD, and FTIR analyses in samples; among which some are well documented as occupational hazards. The trace presence of organic carbon was observed in all FTIR spectra. The most significant outcome of this study is the detection of carcinogenic substances such as crystalline silica (quartz, cristobalite) and asbestoses (anthophyllite, chrysotile, and crocidolite) in samples. For instance, quartz was found in the dust of dust collectors while road dust of the CI showed the existence of both quartz and cristobalite. However, asbestoses were found only in source materials, but they could be released anytime during material handling, thus creating OHE.