【英文标准名称】:StandardTestMethodforSilicainWater
【原文标准名称】:水中二氧化硅的标准试验方法
【标准号】:ASTMD859-2010
【标准状态】:现行
【国别】:
【发布日期】:2010
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D19.05
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:二氧化硅;水;无机化合物-水;比色分析-水;硅钼反应;质量控制-水;二氧化硅含量;废水测试/处理;比色的
【英文主题词】:colorimetric;silica;water;Inorganiccompounds--water;Colorimetricanalysis--water;Molybdate-reactivesilica;Qualitycontrol(QC)--water;Silicacontent;Wastewatertesting/treatment
【摘要】:Siliconcomprisesabout28%ofthelithosphereandis,nexttooxygen,themostabundantelement.Itisfoundastheoxideincrystallineforms,asinquartz;combinedwithotheroxidesandmetalsinavarietyofsilicates;andinamorphousforms.Siliconisthemostabundantelementinigneousrocksandisthecharacteristicelementofallimportantrocksexceptthecarbonates.Itistheskeletalmaterialofdiatomsbutisnotknowntoplayasignificantroleinthestructureofprocessesofhigherlifeforms.Silicaisonlyslightlysolubleinwater.Thepresenceofmostsilicainnaturalwaterscomesfromthegradualdegradationofsilica-containingminerals.Thetypeandcompositionofthesilica-containingmineralsincontactwiththewaterandthepHofthewateraretheprimaryfactorscontrollingboththesolubilityandtheformofsilicaintheresultingsolution.Silicamayexistinsuspendedparticles,asacolloid,orinsolution.Itmaybemonomericorpolymeric.Insolutionitcanexistassilicicacidorsilicateion,dependinguponpH.Thesilicacontentofnaturalwatersiscommonlyinthe5to25mg/Lrange,althoughconcentrationsover100mg/Loccurinsomeareas.Silicaconcentrationisanimportantconsiderationinsomeindustrialinstallationssuchassteamgenerationandcoolingwatersystems.Undercertainconditions,silicaformstroublesomesilicaandsilicatescales,particularlyonhigh-pressuresteamturbineblades.Incoolingwatersystems,silicaformsdepositswhensolubilitylimitsareexceeded.Incontrast,silicamaybeaddedasatreatmentchemicalinsomesystems,forexample,incorrosioncontrol.Silicaremovaliscommonlyaccomplishedbyionexchange,distillation,reverseosmosis,orbyprecipitation,usuallywithmagnesiumcompoundsinahotorcoldlimesofteningprocess.1.1Thistestmethodcoversthedeterminationofsilicainwaterandwastewater;however,theanalystshouldrecognizethattheprecisionandaccuracystatementsforreagentwatersolutionsmaynotapplytowatersofdifferentmatrices.1.2Thistestmethodisacolorimetricmethodthatdeterminesmolybdate-reactivesilica.Itisapplicabletomostwaters,butsomewatersmayrequirefiltrationanddilutiontoremoveinterferencesfromcolorandturbidity.Thistestmethodisusefulforconcentrationsaslowas20x03BC;g/L.1.3Thistestmethodcoversthephotometricdeterminationofmolybdate-reactivesilicainwater.Duetothecomplexityofsilicachemistry,theformofsilicameasuredisdefinedbytheanalyticalmethodasmolybdate-reactivesilica.Thoseformsofsilicathataremolybdate-reactiveincludedissolvedsimplesilicates,monomericsilicaandsilicicacid,andanundeterminedfractionofpolymericsilica.1.4Theusefulrangeofthistestmethodisfrom20to1000x03BC;g/Latthehigherwavelength(815nm)and0.1to5mg/Latthelowerwavelength(640nm).Itisparticularlyapplicabletotreatedindustrialwaters.Itmaybeappliedtonaturalwatersandwastewatersfollowingfiltrationordilution,orboth.Forseawaterorbrines,thistestmethodisapplicableonlyifmatchedmatrixstandardsorstandardadditiontechniquesareemployed.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.Note18212;Formanynaturalw......
【中国标准分类号】:C51
【国际标准分类号】:13_060_50
【页数】:5P.;A4
【正文语种】: