Direct transformation of FGD gypsum to calcium sulfate hemihydrate whiskers: Preparation, simulations, and process analysis

(整期优先)网络出版时间:2015-02-12
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Calciumsulfatehemihydrate(CSH)whiskersweresynthesizedbyphasetransitioninCaCl2solutionunderatmosphericpressure.Analytical-gradecalciumsulfatedihydrate(ARCSD)wasusedastherawmaterialforthesynthesisofCSHwhiskers,accordingtoorthogonalexperiments.Theeffectsofreactiontemperature,ARCSDcontent,H2SO4content,andreactiontimewereinvestigated,andthecrystallizationconditionswereoptimized.Theas-preparedCSHwhiskersdisplayedaregularmorphologyandahighlyuniformsize,withanaspectratioof105.AsimulationsystemwasalsoestablishedbyblendingvarioussulfateswithARCSD,toevaluatetheeffectsofimpuritiesinfluegasdesulfurization(FGD)gypsum.ThemainaimwastoprepareCSHwhiskersdirectlyfromFGDgypsum,withoutanypurification,usingtheoptimizedconditions.Thisisafacilepotentialalternativeprocessforlarge-scaleproductionofCSHwhiskersusingabundantFGDgypsumassourcematerials.