Transformation of flue gas desulfurization (FGD) gypsum to β-CaSO4·0.5H2O whiskers using facile water treatment

A novel way for the transformation of flue gas desulfurization (FGD) gypsum, an industrial by-product to β-CaSO4·0.5H2O whiskers is investigated for calcium sulfate-rich alternative construction material. As the consumption of gypsum products is increasing in the construction industry and a limited amount of natural gypsum is available, herein facile water treatment is used to generate fine tubular particles by recrystallization and growth of β-CaSO4·0.5H2O without any chemical for the first time. Remarkable properties of FGD gypsum are characterized with mean particle size of 42.875–48.759 µm, bulk density of 1.08–1.21 g/cm3, and specific gravity of 3.06–3.35. XRD, FTIR, WD-XRF, FESEM-EDS, and HR-TEM analysis confirm the composition and morphology of the synthesized material. XRD pattern of treated FGD gypsum confirms the presence of highly crystalline β-CaSO4·0.5H2O. FESEM micrographs confirm the micro-needle type morphology with a very high aspect ratio of 25:1.Results showed that magnetic stirring improves the removal efficacy of impurities. This study will open the perspective for the development of FGD gypsum whiskers with a very high aspect ratio and will pave the way for future investigation for a green alternative of natural gypsum for construction applications. © 2021 Elsevier B.V