XRD peak broadening modelling for Al-alloys characterization compared with Rietveld profile analysis

Mostafa, Mostafa; Mostafa, Ahmed; Abdel‐Rahman, Mohamed A.E.; Assem, E.E.; Ashour, A.; Badawi, Emad A.

doi:10.1016/j.matpr.2023.04.252

Cited by 4 publications

(1 citation statement)

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“…The characteristic peak (28.5) with the highest peak intensity was selected as a typical peak to evaluate the change of full width at half-maximum of the calcium fluoride crystals. The full width at half-maximum of the calcium fluoride crystals increased from 0.258 to 0.697 with an increase in the doping amount of sulfate, which could indicate a worsened crystallinity of calcium fluoride due to the doped sulfate , (Figure b). The size of calcium fluoride crystallites decreased accordingly, from 38.0 to 14.6 nm (Figure c).…”

Section: Resultsmentioning

confidence: 99%

Sulfate Doping Promotes Agglomeration of Calcium Fluoride Crystals

Wang,

Zhang,

et al. 2024

Environ. Sci. Technol.

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Calcium salt precipitation is an effective solution to wastewater fluoride pollution. The purity and precipitation efficiency of calcium fluoride is critical for its removal and recovery. This study aimed to reveal the role of coexisting sulfates in the precipitation of calcium fluoride. A low sulfate concentration promoted calcium fluoride precipitation. The size of calcium fluoride-aggregated particle clusters increased from 750 to 2000 nm when the molar ratio of sulfate to fluoride was increased from 0 to 3:100. Sulfate doped in the calcium fluoride crystals neutralized the positive charge of the calcium fluoride. Online atomic force microscopy measurements showed that sulfate reduced the repulsive force between calcium fluoride crystals and increased the adhesion force from 1.62 to 2.46 nN, promoting the agglomeration of calcium fluoride crystals. Sulfate improved the precipitation efficiency of calcium fluoride by promoting agglomeration; however, the purity of calcium fluoride was reduced by doping. Sulfate reduced the induction time of calcium fluoride crystallization and improved the nucleation rate of calcium fluoride. Sulfate should be retained to improve the precipitation of calcium fluoride and to avoid its loss from the effluents. However, it is necessary to separate sulfate from fluoride to obtain highpurity calcium fluoride. Therefore, sulfate concentration regulation in high-fluoride wastewater is key to achieving the efficient removal and recovery of fluoride ions.

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Section: Resultsmentioning

confidence: 99%