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:1008-7524(2004)07-0015-03X,(,063000):,pH,,,X-ray:;;:TQ062:A0,,([1])[2],[3],,11.1X-ray1.21122.1,,20%11(100%)/5060708090100/%6382951009750,50,SiO250100,,,7090,,6585,,,2.2pHpH:pH119,,,pH7,2,pHX-ray,pH=7SiO2,51IM&P20047X:2003-12-01pH:pH5,,;pH57,pH,;pH10.5,pHpH78,2pHX-ray(100%)pH57911/%10087902.3,3,SiO2,SiO2,pH24,SiO27.5%10.0%3SiO2SiO2/%pH/h7.579.6410.102.02.02.0361554/h/(gmL-1)[mL(100)-1]/(m2g-1)320h0.165260185420h0.160245167520h0.175265192120h0.172225145220h0.1592701674,,,2.480n=2.6X-rayn=3.280%,,,;,,,,,,;,,,78,40%2.5X-ray:303,0.44;716,0.64,,,SiO2,,,[4],,,,[5]2.6SiO2,,1520nmX-ray::a=4.1797,c=2.6659,z=2:v=46.56DX=4.28661IM&P20047Scherrer(D=k/Bcos),36nm23X-ray37090;pH78;,4[1],.[J].,2000,(4):23-25.[2],.-[J].,1998,29(2):131.[3],.[J].,2002,(1):16-19.[4],.[J].,2002,34(1):18-20.[5].[J].(),2002,23(3):23-25.Studyonthecontrolofprocesspa2rametersinpreparingnano2silicaaero2gelwithprecipitationmethodXUYing,SHENYi(HebeiInstituteofTechnology,HebeiTangshan063000,China)Abstract:Duringthetestofpreparingnano2silicaaerogelwithsmallsizeandgoodqualitycouldbegotbyadjustingsynthesiscondi2tions,suchasconcentrationofacid,temperatureofactionsystem,pHvalue,rawmaterialparametersetc.,andoptimizingprocesspa2rameters.Thestructureofnano2silicaaerogelwasstudiedwithX2raydiffractioninstrumentandscanningelectronmicroscope.Keywords:silicaaerogel;precipitationmethod;processparame2ter(14),(2)K+NH4+//Cl-SO42-CH3OH-H2O,,4[1],.[J].,1997,(1):13-15.[2],,.[J].,1997,(12):32-34.[3],,.CaCO3K2SO4[J].,2003,(4):13-15.[4],,.[J].,1999,(1):52-54.[5].[M].:,1986.Studyonthephasediagramofthesecondstepreactionsystemofsynthe2sispotassiumsulfatebygypsumtwostepmethodZHANGXing2fa1,LIUShou2qiang2,LIUJun2sheng3,HUZhang2wen2(1.HefeiUniversityofTechnology,HefeiAnhui230009,China;2.AnhuiUniversityofTechnologyandScience,WuhuAnhui241000,China;3.UniversityofScienceandTechnologyofChina,HefeiAnhui230026,China)Abstract:Thekeyquestionofsynthesisofpotassiumsulfatewithgypsumtwostepmethodisthelowrateofinversioninthesecondstepreaction.Therateofinversioncouldbeincreasedeffectivelybyaddingorganicsolventtothesystemofreaction,inwhichmethylal2coholwasregardedasmoreappropriate.Thus,thephasediagramofthesecondstepreactionsystemat25wasinvestigatedbymeansofcertainsolutionofmethylalcoholassolvent,thepurposewastoim2provetheprocesswhichwasusing.Keywords:gypsum;potassiumsulfate;phasediagram71IM&P20047