Characterization of UPR-Steel slag composite: effects of steel slag content and particle size

Steel slag is an industrial waste that can be used in unsaturated polyester resin (UPR) as filler. The aim of this study is to create a UPR-steel slag composite with varying amounts of steel slag and particle sizes. The steel slag was first milled for 40 hours in a ball mill and then compression molded with UPR. The phase identification, crystallinity, and morphology of the as-milled and UPR-SS composites were examined. The as-milled steel slag, primarily composed of iron oxide and silicates, influenced the crystallinity of the composites based on the steel slag loading and particle size. This study determined that both the total amount of steel slag and its particle size have an impact on phase, functional group, and morphology of UPR-SS composites. The X-ray diffraction (XRD) analysis revealed that the composite exhibited a high degree of crystallinity, with composites containing steel slag particles measuring 125 μm in size, as opposed to 45 μm. In order to enhance the formation of crystals and decrease the size of grains in the UPR matrix, the utilization of small steel slag particles measuring 45 μm was employed. Furthermore, it is more likely that the composite with 125 μm will exhibit lower absorption compared to the composite with 45 μm steel slag materials. This is due to the fact that the width, intensity, and area of bands in FTIR spectra of composites are directly dependent on the average particle size of the composite. Within the UPR matrix, the incorporation of SS with particle sizes of 45 μm results in a more uniform distribution compared to the 125 μm steel slag, as determined by scanning electron microscopy (SEM).