The formation of alite phase by using phosphogypsum and oil shale

This study aims at gaining in-depth knowledge for the cement clinker production by utilizing phosphogypsum (PG) and oil shale (OS) as raw materials. The raw mixtures (Raw Mixes I and II) were burnt in a muffle furnace and then analyzed by X-ray diffraction (XRD) to observe the phases obtained. While minor amounts of alite (C3S) and major amounts of anhydrite phases were observed with the Raw Mix I containing 40.72% PG refined with water and lime wash by two and three times, respectively (PGR23), in N2 atmosphere at 1300 deg. C, minor amounts of alite (C3S), free CaO and major amounts of anhydrite phases were formed in air atmosphere at 1300 deg. C with the Raw Mix II containing 40.72% PG refined with water and lime wash by three and four times, respectively (PGR34). The change of burning medium and the increase in the number of wash with water and lime, respectively, resulted in any difference in terms of the formation of the alite peaks; however, the intensity and the amount of anhydrite peaks were decreased in N2 atmosphere due to the more conversion of that to the oxide compared to that in air atmosphere