Preparation of Large-grained anhydrite(VI) γ-CaSO<sub>4</sub> with FGD gypsum

Gao, Lili; Shao, Duoduo; Qin, Ying; Tao, Jinwen; Wang, Dongyan; Cao, Jilin

doi:10.1080/15567036.2019.1604864

Cited by 2 publications

(3 citation statements)

References 19 publications

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“…In addition, short and columnar II‐CaSO 4 prepared by way of Eqns. (4) and (5) under dosage adjustment of the crystal control agent was denoted as C‐II‐CaSO 4 33 . Figs.…”

Section: Resultsmentioning

confidence: 99%

“…The hydrothermal method was first used to convert OM-gypsum into γ-CaSO 4 following a procedure like that previously reported. 33,34 OM-gypsum (9.0 wt%), MgCl 2 6H 2 O (0.07 mol/L), and HCl (0.44 mol/L) were added in a Teflon liner containing 50 mL of distilled water under stirring for 10 min. Then, this mixture was transferred into the homogeneous reactor at 120 °C for 2.5 h with the stirring speed of 10 rpm.…”

Section: Whiskersmentioning

confidence: 99%

“…( 4) and ( 5) under dosage adjustment of the crystal control agent was denoted as C-II-CaSO 4 . 33 Figs. 9,10 show the SEM images of three different II-CaSO 4 crystals with their corresponding aspect ratios.…”

Section: Adsorption Mechanismmentioning

confidence: 99%

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Synthesis of robust insoluble anhydrite whiskers from desulphurization gypsum containing organic matter via improved hydrothermal‐calcination process for the removal of lead and zinc ions

Liu

et al. 2022

J of Chemical Tech & Biotech

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Background: An improved hydrothermal-calcination method was used to convert desulphurization gypsum containing organic matter (OM-gypsum) to insoluble anhydrite (II-CaSO 4 ) whiskers, where OM-gypsum was directly transformed to soluble anhydrite (γ-CaSO 4 ) whiskers via the hydrothermal method followed by calcination. The synthesized II-CaSO 4 whiskers were applied for the removal of lead ion (Pb(II)) and zinc ion (Zn(II)).Results: The synthesized II-CaSO 4 whiskers possessed a smooth surface, large aspect ratio, and high whiteness of above 90%. The mother liquor after synthesis could be recycled. The synthesized II-CaSO 4 whiskers exhibited maximum adsorption capacities of 641.03 mg/g and 14.00 mg/g for Pb(II) and Zn(II), respectively, under optimal adsorption conditions. The pseudo-second-order model and Langmuir isotherm model were appropriate for describing the adsorption process of II-CaSO 4 whiskers. Compared with II-CaSO 4 whiskers calcined from hemihydrate gypsum and the short and columnar II-CaSO 4 crystals, the synthesized II-CaSO 4 whiskers in this work possessed a superior adsorption performance. Conclusion:The improved hydrothermal-calcination process could completely remove the organic matter from OM-gypsum, and the direct formation of γ-CaSO 4 intermediate helped avoid the lattice collapse caused by the removal of water molecules during calcination. The excellent adsorption performance of the synthesized II-CaSO 4 whiskers in this work could be attributed to their large negatively charged surface areas, which were formed by the large aspect ratio and excellent stability. This work provides a practical method for the comprehensive utilization of chemical gypsum containing organic impurities.

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“…In addition, short and columnar II‐CaSO 4 prepared by way of Eqns. (4) and (5) under dosage adjustment of the crystal control agent was denoted as C‐II‐CaSO 4 33 . Figs.…”

Section: Resultsmentioning

confidence: 99%

Section: Whiskersmentioning

confidence: 99%