《工业分析 Industrial Analysis》课件-项目七：硅酸盐分析

项目七：硅酸盐分析任务一：认识硅酸盐及其分析系统认识硅酸盐及其分析系统课程：工业分析中文Scenario7:SilicateAnalysisTask1:UnderstandingsilicatesandtheiranalyticalsystemsUnderstandingsilicatesandtheiranalyticalsystemsCourse:IndustrialAnalysisEglish一、硅酸盐组成及种类硅酸盐就是硅酸的盐类，就是由二氧化硅和金属氧化物所形成的盐类。换句话说，是硅酸（xSiO2·y

H2O）中的氢被Al、Fe、Ca、Mg、K、Na及其它金属取代形成的盐。中文一、CompositionandtypesofsilicatesSilicatesaresaltsofsilicicacid,whicharesaltsformedfromsilicaandmetaloxides.Inotherwords,itisasaltformedbythesubstitutionofhydrogeninsilicicacid(xSiO2·yH2O)withAl,Fe,Ca,Mg,K,Na,andothermetals.Eglish1、硅酸盐的分子式硅酸盐分子式很复杂，如：

白云母：[KAl2(AlSi3O10)(OH)2]

正长石：K2Al2Si6O16通常用硅酸酐和构成硅酸盐的所有金属氧化物的分子式分开写以表示之，例如：正长石分开写清晰中文1、MolecularformulaofsilicatesThemolecularformulaofsilicatesisverycomplex,suchas：

muscovite：[KAl2(AlSi3O10)(OH)2]

orthoclase：K2Al2Si6O16Usually,themolecularformulasofsilicicanhydrideandallmetaloxidesthatmakeupsilicatesarewrittenseparatelytorepresentthem,forexample:orthoclase:ThemolecularformulaswrittenseparatelylookclearEglish2、硅酸盐分类中文2、ClassificationofsilicatesNaturalsilicate:Artificialsilicate:Feldspar,quartz,mica,asbestos,talc,clay,kaolinCement,glass,ceramics,refractorymaterials,bricksandtiles,enamelEglish二、硅酸盐分析系统1、硅酸盐的分析意义地质学意义：了解岩石成分变化，指导地质勘探工业建设方面：判断岩石矿物组成，确定其用途工业生成方面：指导监控生产工艺，鉴定产品质量中文二、Silicateanalysissystem1、ThesignificanceofsilicateanalysisGeologicalsignificance:UnderstandingchangesinrockcompositionandguidinggeologicalexplorationIntermsofindustrialconstruction:DeterminethemineralcompositionofrocksanddeterminetheirusesIntermsofindustrialproduction:guideandmonitorthegenerationprocess,identifyproductqualityEglish2、硅酸盐的分析项目SiO2、Fe2O3、Al2O3、CaO、MgO、K2O、Na2O、TiO2、MnO、FeO、P2O5、烧失量，水分、不溶物等中文2、AnalysisprojectofsilicatesSiO2、Fe2O3、Al2O3、CaO、MgO、K2O、Na2O、TiO2、MnO、FeO、P2O5、lossonignition,moisture,insolublesubstances,etcEglish3、系统分析和分析系统系统分析：称样一份分解后，通过分离或掩蔽的方法消除干扰离子对测定的影响，再系统的、连贯地进行数个项目的依次测定。

分析系统：是在系统分析中从试样分解、组成分离到依次测定的程序安排。中文3、SystemAnalysisandAnalysisSystemSystemanalysis:Afterthesampleisweighedanddecomposed,theinterferenceofionsonthemeasurementiseliminatedthroughseparationormaskingmethods,andthenseveralitemsaresystematicallyandcoherentlymeasuredinsequence.Analysissystem:Itisaprogramarrangementinsystemanalysisthatinvolvessampledecomposition,compositionseparation,andsequentialdetermination.Eglish操作简单D易实现自动化好分析系统优点ECAB称样次数少好的精密度和准确度适用范围广中文EasytooperateDEasytoachieveautomationTheadvantagesofagoodanalysissystemECABLesssampleweighingtimesGoodprecisionandaccuracyWideapplicabilityEglish

硅酸盐岩石分析系统快速分析系统：结合重量法、滴定法、比色法、电化学法，包括碱熔快速分析、酸溶快速分析、锂硼酸盐熔融分解系统经典分析系统：建立在沉淀分离和重量法的基础上快速分析系统：结合重量法、滴定法、比色法、电化学法，包括碱熔快速分析、酸溶快速分析、锂硼酸盐熔融分解系统经典分析系统：建立在沉淀分离和重量法的基础上中文Silicaterockanalysissystem快速分析系统：结合重量法、滴定法、比色法、电化学法，包括碱熔快速分析、酸溶快速分析、锂硼酸盐熔融分解系统经典分析系统：建立在沉淀分离和重量法的基础上Rapidanalysissystem:combininggravimetric,titration,colorimetric,andelectrochemicalmethods,includingalkalimeltrapidanalysis,acidsolutionrapidanalysis,andlithiumboratemeltdecompositionsystemClassicanalysissystem:basedonprecipitationseparationandgravimetricmethodEglishFe2O3H2O2光度法Al2O3SiO2TiO2K2Cr2O7滴定灼烧、称重沉淀SiO2·nH2O溶液：Al3+、Fe3+、Ti4+R2O3K2S2O7熔融，稀H2SO4提取、过滤灼烧、称重沉淀Fe2O3·nH2O、Al2O3·nH2O、TiO2·nH2O差减法MgNH4PO4沉淀溶液弃去MgO灼烧、称重沉淀CaC2O4灼烧称重CaONH4HPO4沉淀、过滤氨水沉淀，过滤灼烧、称重；HF处理后灼烧、称重SiO2K2S2O7熔融，稀H2SO4提取溶液：Ca2+、Mg2+（NH4）2C2O4沉淀、过滤溶液：Mg2+试样Na2CO3熔融，水提取，HCl酸化，过滤沉淀SiO2+杂质溶液：Al3+、Fe3+、Ti4+、Ca2+、Mg2+经典分析系统MgOCaOAl2O3Na2OK2O光度法沉淀络合滴定法硫酸溶解滤液火焰光度法络合滴定法Fe2O3TiO2MnOP2O5制成H2SO4溶液，氨水沉淀分离试样H2F2+H2SO4在聚四氟乙烯容器中分解

酸溶快速分析系统项目七：硅酸盐分析任务二：硅酸盐试样制样方法硅酸盐试样制样方法课程：工业分析中文Scenario7:SilicateAnalysisTask2:PreparationmethodofsilicatesamplesPreparationmethodofsilicatesamplesCourse:IndustrialAnalysisEglish一、硅酸盐试样的处理制备过程：破碎过筛混匀磨碎：取样前研细至粒径≤0.080mm试样的烘干：用烘干法除去试样吸附的水分过筛混匀缩分缩分中文一、TreatmentofsilicatesamplesPreparationprocess：crush过筛混匀Grinding:Finegrindtoaparticlesizeof≤0.080mmbeforesamplingDrying:Usethedryingmethodtoremovethemoistureadsorbedonthesamplesievemix缩分reduceEglish二、硅酸盐试样的分解1、试样分解目的

2、试样的分解要求（1）完全简单快速（2）分解无损失（3）无干扰引入中文二、Decompositionofsilicatesamples1、Thepurposeofsampledecomposition

2、Sampledecompositionrequirements(1)Complete,simple,andfast(2)Decompositionwithoutloss(3)WillnotintroduceinterferingsubstancessolidsampleconvertsamplesolutionEglish3、试样分解的原理（理论依据）中文3、Theprincipleofsampledecomposition(theoreticalbasis)AlkalinemetaloxidesSmallratio,easilysolublebyacidHighratio,easilysolublebyalkaliMarble,limestoneCementclinkerAlkalineslagRawmaterials,clayIronoreEglish4、试样的分解处理方法中文4、Sampledecompositionmethodinclude:Dissolutionmethod:water

soluble,acidsoluble,otherdissolutionmethodsMeltingmethod:reagentSemimeltingmethodEglish（1）酸溶解法SiO2碱金属氧化物比值越小，碱性越强，越易被酸溶解硅酸盐分析中所用的酸：HCl，HNO3，H2SO4，H3PO4，HF等。中文（1）AciddissolutionmethodSiO2AlkalimetaloxideThesmallertheratio,thestrongerthealkalinity,andtheeasieritistobedissolvedbyacidAcidsusedinsilicateanalysis:HCl，HNO3，H2SO4，H3PO4，HF,etc.EglishHCl：系统分析中HCl是良好的溶剂特点：

a.生成的氯化物除AgCl、Hg2Cl2、PbCl2外都能溶于水，给测定带来方便。（硅酸盐样品中几乎不含Ag+、Hg22+、Pb2+）

b.Cl-与某些离子生成络合物FeCl63-促进试样分解

c.浓HCl沸点较低（bp108℃），用重量法测SiO2易于蒸发除去

d.大多数硅酸盐样品不能被HCl分解（熟料碱性矿渣可以）中文HCl：HClisagoodsolventinsystemanalysisFeatures:a.Thegeneratedchlorides,exceptforAgCl,Hg2Cl2,andPbCl2,aresolubleinwater,makingthedeterminationconvenient.(ThesilicatesamplecontainsalmostnoAg+,Hg22+,Pb2+)b.Cl-formscomplexeswithcertainions,FeCl63-promotessampledecompositionc.ConcentratedHClhasalowerboilingpoint(bp108℃),makingiteasiertoevaporateandremovehydrochloricacidwhenmeasuringSiO2usingthegravimetricmethodd.ThedisadvantageisthatmostsilicatesamplescannotbedecomposedbyHClEglishHNO3、H2SO4、H3PO4：在系统分析中很少用HNO3、H2SO4溶样a.HNO3溶样，重量法测SiO2，加热蒸发过程中易形成难溶性碱式盐沉淀b.H2SO4易形成溶解度小、或不溶的碱土金属硫酸盐，干扰测定c.H3PO4（缩合的H3PO4）200~300˚C溶解能力很强，能溶解一些难溶于HCl、H2SO4的样品，如铁矿石、钛铁矿等，但只适用于单项测定。特点：中文HNO3,H2SO4,H3PO4：HNO3andH2SO4arerarelyusedtodissolvesamplesinsystemanalysisa.WhendissolvingsampleswithHNO3andmeasuringSiO2usingthegravimetricmethod,insolublealkalinesaltprecipitatesareeasilyformedduringtheheatingandevaporationprocessb.H2SO4easilyformsalkalineearthmetalsulfateswithlowsolubilityorinsolubility,whichinterferewiththedeterminationc.Between200and300

℃,H3PO4hasastrongsolubilityandcandissolvesomesamplesthataredifficulttodissolveinHClandH2SO4,suchasironore,ilmenite,etc.,butitisonlysuitableforsingleitemdetermination.Features:Eglish但有干扰，如HF及HF-H2SO4、HF-HClO4混酸大多数的硅酸盐样品均能被HF分解。残渣为除Si外的其它盐类，以水提取加酸溶解，或熔融法处理成试样溶液。

中文Butthereisinterference,suchasHF,HF-H2SO4,HF-HClO4MostsilicatesamplescanbedecomposedbyHF.

TheresidueisasaltotherthanSi,whichisextractedwithwateranddissolvedinacid,orprocessedintoasamplesolutionbymeltingmethod.

Eglish（2）熔融或半熔法什么是熔融法或半熔法？（干法）将试样与熔剂混合在高温下加热熔融，使欲测组分变为可溶于水或酸中的化合物（K、Na盐、硫酸盐、氯化物）熔融或半熔的目的？利用熔剂，借助高温熔融或半融的方法，增加碱金属氧化物的比值，使本来不能被酸直接分解的试样能被酸分解。中文（2）MeltingorsemimeltingmethodWhatisthemeltingmethodorsemimeltingmethod?(Drymethod)Mixthesamplewiththefluxandheatitathightemperaturetomeltthedesiredcomponentintocompounds(K,Nasalts,sulfates,chlorides)thataresolubleinwateroracidThepurposeofmeltingorsemimelting?Byusinghigh-temperaturemeltingorsemimeltingmethods,theratioofalkalimetaloxidesisincreased,sothatsamplesthatcannotbedirectlydecomposedbyacidcanbedecomposedbyacid.Eglish熔剂：碱金属的化合物：Na2CO3，K2CO3，NaOH，KOH，Na2O2，K2S2O7

熔融法分类：碱熔法：用碱性溶剂，熔酸性试样，如Na2CO3酸熔法：用酸性溶剂，熔碱性试样，如K2S2O7中文Meltingsolvent：basicmeltingsolvent：Na2CO3，K2CO3，NaOH，KOH，Na2O2acidmeltingsolvent：K2S2O7

Classificationofmeltingmethod:Alkalimeltingmethod:usingalkalinesolventstomeltacidicsamplesAcidmeltingmethod:usinganacidicsolventtomeltanalkalinesampleEglishMnClAlClSiOH如HCl酸分解)(MnONaOAlONaSiONaC1000150CONa23324232232o32熔融物锰酸钠铝酸钠硅酸钠硅酸盐×-当硅酸盐与Na2CO3熔融时，硅酸盐便被分解为碱金属硅酸钠、铝酸钠、锰酸钠等复杂的混合物。熔融物用酸处理时，则分解为相应的盐类并析出硅酸。中文

WhensilicatesaremixedwithNa2CO3andmelted,theyaredecomposedintocomplexmixturessuchasalkalimetalsodiumsilicate,sodiumaluminate,andsodiummanganeseoxide.Whenthemoltenmaterialistreatedwithacid,itdecomposesintocorrespondingsaltsandprecipitatessilicicacid.MnClAlClSiOH酸分解)(MnONaOAlONaSiONaC1000150CONa23324232232o32熔融物SodiummanganatesodiumaluminateSodiumsilicatesilicate×-decomposewithacidEglish如高岭土Al2O32

SiO2

2

H2O

+

3

Na2CO3

=

2

Na2SiO3

+

Na2O

Al2O3

+

3

CO2

+

2

H2OHCl处理Na2O

Al2O3

+

8

HCl2

AlCl3

+

2

NaCl

+

4

H2ONa2SiO3

+

2

HCl

H2SiO3

+

2

NaCl熔样过程中文example：kaolinAl2O32

SiO2

2

H2O

+

3

Na2CO3

=

2

Na2SiO3

+

Na2O

Al2O3

+

3

CO2

+

2

H2OTreatwithHCl

Na2O

Al2O3

+

8

HCl2

AlCl3

+

2

NaCl

+

4

H2ONa2SiO3

+

2

HCl

H2SiO3

+

2

NaClEglish器皿：坩埚（灼烧、熔融、烧结试样）有：瓷、石英坩埚，铁、镍、银、铂金、黄金坩埚中文Vessel:Crucible(usedforburning,melting,andsinteringsamples)Thereare:porcelain,quartzcrucibles,iron,nickel,silver,platinum,andgoldcruciblesRulesforvesselselection：◆Selectaccordingtothepropertiesoftheflux:acidicfluxescannotbeusedinAg,FeandNicrucibles;Alkalinefluxcannotbeusedinquartzorporcelaincrucibles;Strongalkalinityandstrongoxidizingflux

cannot

beusedinPt

crucible◆Selectionbasedonmeltingpointmp:Agmp960.5℃,Na2CO3

mp

851℃,whenusingNa2CO3asaflux,itcancausedeformationandmeltingofthesilvercrucible◆DissolvingsampleswithHFshouldbedoneinplasticcontainers,plasticcups,plasticcrucibles,orplatinumvesselsEglish溶剂名称坩埚材料铂镍铁银石英瓷Na2CO3K2CO3+++-Agmp低--石墨作垫层可NaOHKOH-碱性强腐蚀大+++--K2S2O7KHSO4+---++Na2O2+++--中文SolventnameCruciblematerialPtNiFeAgquartzporcelainNa2CO3K2CO3+++-lowmeltingpoint--+(Graphitecushionlayer)NaOHKOH-Strong

alkalinitySeverecorrosion+++--K2S2O7KHSO4+---++Na2O2+++--Eglish项目七：硅酸盐分析任务三：硅酸盐质量分析硅酸盐中二氧化钛含量测定—二安替比林甲烷光度法课程：工业分析中文Scenario7:SilicateAnalysisTask3:QualityanalysisofsilicatesDeterminationoftitaniumdioxidecontentinsilicatesCourse:IndustrialAnalysisEglish中文Titrationmethod◆Bitteralmondaciddisplacementcoppersaltbacktitrationmethod◆HydrogenperoxidecoordinationbismuthsaltbacktitrationmethodPhotometricmethodHydrogenperoxidespectrophotometryTitaniumironreagentspectrophotometryDiantipyrylmethanephotometricmethodDeterminationmethodoftitaniumdioxideLowcontent,commonlyusedmethodsEglish1、原理在盐酸介质中，二安替比林甲烷（DAMP)与TiO2+生成稳定的1：3的黄色络合物，在波长420nm处测定吸光度。二安替比林甲烷光度法中文1、principleInhydrochloricacidmedium,diantipyrylmethane(DAMP)formsastable1:3yellowcomplexwithTiO2+,andtheabsorbanceofthecomplexismeasuredatawavelengthof420

nm.DiantipyrylmethanephotometricmethodEglish2、试剂和仪器（1）试剂①

盐酸溶液：（1+2）、（1+11）②抗坏血酸溶液：5g/L，将0.5g坑坏血酸(Vc)溶于100mL水中，过滤后使用。用时现配。③二安替比林甲烷溶液：10g/L盐酸溶液，将5g二安替比林甲烷溶于50mL盐酸1+11中，过滤后使用。（2）仪器分光光度法常用仪器中文2、Reagentsandinstruments(1)Reagents①Hydrochloricacidsolution:(1+2),(1+11)②Ascorbicacidsolution:5g/L,dissolve0.5gofascorbicacid(Vc)in100mLofwater③Diantipyrylmethanesolution:Dissolve5gofDiantipyrylmethanein50mLofhydrochloricacid(1+11)solutionandfilter.(2)InstrumentsCommonlyusedinstrumentsinspectrophotometryEglish3、测定步骤称取0.5000g长石粉+5.3g碳酸钠与四硼酸钠（1+1），于石墨坩埚中混匀，再覆盖1g混合溶剂，在800~850度加热10min，冷却，取出熔块于300mL烧杯中，加入100mL水，20mL浓盐酸，加热溶解，过滤于容量瓶（250mL）中，稀释到刻度。（1）样品溶液的配制中文3、MeasurementstepsWeigh0.5000goffeldsparpowderand5.3gofsodiumcarbonateandsodiumtetraborate(1+1),mixwellinagraphitecrucible,coverwith1gofmixedsolvent,heatat800-850℃for10minutes,cool,removethefritintoa300mLbeaker,add100mLofwaterand20mLofconcentratedhydrochloricacid,heattodissolve,filter,collectthefiltrateinavolumetricflask(250mL),anddilutetothemark.（1）PreparationofsamplesolutionEglish（2）工作曲线的绘制吸取钛标液0.0、2.0、4.0、6.0、8.0、10.0mL分别放入100mL容量瓶中，依次加入10mL盐酸（1+2），10mL抗坏血酸溶液，5mL95%乙醇、20mL二安替比林甲烷溶液，用水稀释至标线，摇匀。放置40min，使用分光光度计，10mm比色皿，以空白溶液作参比于420nm处测定溶液吸光度，绘制工作曲线。中文（2）DrawingofworkcurveTake0.0,2.0,4.0,6.0,8.0,and10.0mLoftitaniumstandardsolutionandputthemintoa100mLvolumetricflask.Add10mLofhydrochloricacid(1+2),10mLofascorbicacidsolution,5mLof95%ethanol,and20mLofdiantipyrylmethanesolutioninsequence.Dilutewithwatertothemarkandshakewell.Letitstandfor40minutes,useaspectrophotometeranda10mmcuvettetomeasuretheabsorbanceofthesolutionat420nmusingblanksolutionasareference,anddrawtheworkingcurve.Eglish从待测液中吸取25.00mL溶液防入100mL容量瓶中，加入10mL盐酸（1+2）及10mL抗坏血酸溶液，放置5min。加入5mL95%乙醇、20mL二安替比林甲烷，用水稀释至标线，摇匀。放置40min后，使用分光光度计，10mm比色皿，用空白溶液作参比，于420nm处测溶液吸光度。（3）样品测定中文Take25.00mLofsolutionfromthetestsolutionandtransferitintoa100mLvolumetricflask.Add10mLofhydrochloricacid(1+2)and10mLofascorbicacidsolution,andletitstandfor5minutes.Add5mLof95%ethanoland20mLofdiantipyrylmethane,dilutewithwatertothemark,andshakewell.Afterbeingleftfor40minutes,useaspectrophotometer,a10mmcuvette,andablanksolutionasareferencetomeasuretheabsorbanceofthesolutionat420nm.（3）SampledeterminationEglish4、结果计算中文4、resultcalculationm4---Themassoftitaniumdioxidein100mLofdeterminationsolution,mg;m---Massofthesample,g;Eglish在加入显色剂前，需加入5毫升乙醇，以防溶液浑浊而影响测定抗坏血酸及二安替比林甲烷溶液不宜久放，应现用现配。5、注意事项中文Beforeaddingthecolorreagent,5millilitersofethanolshouldbeaddedtopreventthesolutionfrombecomingcloudyandaffectingthedeterminationThesolutionofascorbicacidanddiantipyrylmethaneshouldnotbeleftforalongtime,andshouldbepreparedasneeded.5、NoteEglish项目七：硅酸盐分析任务三：硅酸盐质量分析硅酸盐中氧化铝含量测定课程：工业分析中文Scenario7:SilicateAnalysisTask3:QualityanalysisofsilicatesDeterminationofaluminacontentinsilicatesCourse:IndustrialAnalysisEglish水泥及其原料系统分析中，Al2O3的测定通常采用EDTA直接滴定法和CuSO4返滴定法，而且一般是在滴定Fe3＋之后的溶液中连续滴定铝。本方法已列入水泥化学分析方法国家标准。直接滴定法为基准法，适用于MnO含量

0.5%的试样；返滴定法为代用法，适用于MnO含量

0.5%的试样。中文Intheanalysisofcementanditsrawmaterialsystems,thedeterminationofAl2O3isusuallycarriedoutusingEDTAdirecttitrationmethodandCuSO4backtitrationmethod,andaluminumisgenerallycontinuouslytitratedinthesolutionaftertitrationwithFe3+.Thismethodhasbeenincludedinthenationalstandardforchemicalanalysismethodsofcement.Thedirecttitrationmethodisthereferencemethod,suitableforsampleswithMnOcontent>0.5%;Thebacktitrationmethodisasubstitutemethod,suitableforsampleswithMnOcontent<0.5%.Eglish一、直接滴定法在pH=3的溶液中，加热，使TiO2+水解为TiO（OH)2沉淀，以PAN和CuY为指示剂，用EDTA标液直接滴定溶液中的

Al3+。反应如下：1、方法原理中文一、DirecttitrationmethodInasolutionwithpH=3,heattohydrolyzeTiO2+intoTiO2(OH)2precipitate,andusePANandCuYasindicatorstodirectlytitrateAl3+inthesolutionwithEDTAstandardsolution.Thereactionisasfollows:1、MethodprincipleAttheendpoint,thesolutioncolour

changesfromredtoyellowred(yellow)Eglish2、测定步骤在滴定完铁的溶液中加入1~2滴溴酚蓝指示剂（2g/L），滴加氨水（1+2）至溶液出现蓝紫色，再滴加盐酸（1+2）至黄色，加入15mL醋酸-醋酸钠缓冲溶液（pH=3），加热至微沸，加入10滴CuY和2~3滴PAN指示剂，用EDTA标准溶液滴定至溶液变为亮黄色。中文2、MeasurementstepsAdd1-2dropsofbromophenolblueindicator(2g/L)tothesolutionaftertitrationofiron,addammoniawater(1+2)dropwiseuntilthesolutionturnsbluepurple,thenaddhydrochloricacid(1+2)dropwiseuntilitturnsyellow,add15mLofaceticacidsodiumacetatebuffersolution(pH=3),heatuntilslightlyboiling,add10dropsofCuYand2-3dropsofPANindicator,andtitratewithEDTAstandardsolutionuntilthesolutionturnsbrightyellow.Eglish3、结果计算中文3、ResultcalculationAl2O3%c--ConcentrationofEDTAstandardsolution,mol/LV--VolumeofEDTAstandardsolution,mLM--MolarmassofAl2O3,g/molm--Massofthesample,gEglish4、注意事项（1）最适宜pH2.5~3.5<2.5Al3+

与EDTA络合不完全；>3.5Al3+

水解倾向增大→偏低（2）指示剂用量PAN适量（2-3d）多→色深→不好观色（3）终点控制（如何控制终点？）由于Al3+与EDTA反应较慢，故经反复煮沸，反复滴定，一般3次即可出现稳定的黄色，其准确度满足生产要求。中文4、Note(1)ThemostsuitablepHis2.5~3.5pH<2.5:incompletecomplexationofAl3+withEDTA;pH>3.5:Al3+hydrolysistendencyincreases→measurementresultislow(2)Indicatordosage

AppropriateamountofPAN(2-3drops),excessive→solutioncolordark→difficulttoobservechangesinsolutioncolor(3)Endpointcontrol(howtocontroltheendpoint?)

DuetotheslowreactionbetweenAl3+andEDTA,itisnecessarytorepeatedlyboilandtitrate.Generally,astableyellowcolorcanappearafter3repetitions,anditsaccuracymeetsproductionrequirements.Eglish二、返滴定法1、方法原理中文二、Backtitrationmethod1、MethodprincipleSolutionaftertitrationofFe3+AddexcessEDTAheat,TransformingmostofAlintoAlYboilbrightpurpleAlltransformedintoAlYEglish2、反应中文2、Chemicalreactionsinvolved:(colourless)(residual)(blue-green)(yellow)(red)Excessive1dropThepurplishredcoloristheendpointEglish3、注意事项（1）终点颜色紫红色（好）终点颜色与过剩的EDTA量和所加PAN指示剂量有关中文3、Note(1)Colorofsolutionatendpoint:purplishredThecoloroftheendpointisrelatedtotheexcessamountofEDTAandtheindicateddosageofPANaddedToomuchEDTAortoolittlePANToolittleEDTAortoomuchPANEDTAexcessmoderateendpointBluepurpleorblueredPurplishredGenerallyEDTAexcess(i.e.reactionresidue)10-15mLEglish（2）pH调节时间加入过量EDTA，加热至70~80˚C，再调pH3.8~4.0Al3+与EDTA反应慢，过量EDTA及加热均提高反应速度

过量后并不直接调至pH3.8~4.0，目的是让大部分Al3+、TiO2+与EDTA络合，以防pH提高至3.8~4.0水解。中文(2)TimeforpHadjustmentAddexcessEDTAandheatto70-80℃,thenadjustthepHto3.8~4.0ThereactionbetweenAl3+andEDTAisslow,andexcessiveEDTAandheatingbothincreasethereactionrateAfteraddingexcessiveEDTA,thesolutionpHisnotdirectlyadjustedto3.8-4.0.ThepurposeistoallowmostAl3+andTiO2+tochelatewithEDTAtopreventhydrolysiswhenthepHisincreasedto3.8-4.0.Eglish（3）PAN使用PAN与Cu-PAN都不易溶于水，为增大其溶解度，配成PAN的酒精溶液，滴定时在热的条件下进行滴定，一般80-90˚C。（4）滴定的体积：保持在200mL以上，以降低Ca、Mn对测定的干扰。本法测得的是Al、Ti合量，要求高时，用光度法测出Ti量，扣除得准确铝量。中文(3)TheuseofPANPANandCuPANarenoteasilysolubleinwater.Toincreasetheirsolubility,analcoholsolutionofPANispreparedandtitratedunderhotconditions,typically80-90℃.(4)Volumeoftitration

Keepthesolutionvolumeabove200mLtoreducetheinterferenceofCaandMninthedetermination.

ThismethodmeasuresthecombinedamountofAlandTi.Whenhighrequirementsaremet,theamountofTiismeasuredusingthephotometricmethod,andtheaccurateamountofaluminumisobtainedbydeductingthecontentofTi.Eglish项目七：硅酸盐分析任务三：硅酸盐质量分析硅酸盐中CaO和MgO含量测定课程：工业分析中文Scenario7:SilicateAnalysisTask3:QualityanalysisofsilicatesDeterminationofCaOandMgOcontentinsilicatesCourse:IndustrialAnalysisEglish

在硅酸盐中钙和镁通常共存，需同时测定。在经典分析系统中是将它们分开后，再分别以重量法或滴定法分别测定；在快速分析系统中，是在一份溶液中控制不同的条件分别测定钙和镁的含量。由于硅酸盐试样中CaO和MgO含量较高，常用的方法是配位滴定法和原子吸收光谱法。原子吸收分光光度法操作简便、选择性好、灵敏度高，是测定钙、镁的一种较为理想的分析方法。中文

Calciumandmagnesiumusuallycoexistinsilicatesandneedtobemeasuredsimultaneously.Intheclassicalanalysissystem,theyareseparatedandthenmeasuredseparatelybygravimetricortitrationmethods;Inarapidanalysissystem,differentconditionsarecontrolledinasolutiontodeterminethecontentofcalciumandmagnesiumseparately.DuetothehighcontentofCaOandMgOinsilicatesamples,commonlyusedmethodsarecoordinationtitrationandatomicabsorptionspectroscopy.Atomicabsorptionspectrophotometryisanidealanalyticalmethodfordeterminingcalciumandmagnesiumduetoitssimpleoperation,goodselectivity,andhighsensitivity.Eglish一、EDTA配位滴定法分别滴定连续滴定取一份试样，在pH=10时用EDTA测定钙镁总量；然后再取一份试样，在pH=12-13时使镁离子沉淀而用EDTA测定钙离子含量，用差减法计算镁离子含量。取一份试样，先用KOH溶液将试样溶液pH调至12.5~13，用EDTA标准溶液滴定钙离子，然后将溶液酸化至pH为10继续用EDTA滴定镁离子。中文一、EDTAcoordinationtitrationmethodTitrateseparatelyTitrate

continuouslyTakeasampleandmeasurethetotalamountofcalciumandmagnesiumusingEDTAatpH=10;ThentakeanothersampleandprecipitatemagnesiumionsatpH12-13，measurethecalciumioncontentusingEDTAandcalculatethemagnesiumioncontentusingsubtractionmethod.Takeasample,firstadjustthepHofthesamplesolutionto12.5-13withKOHsolution,titratecalciumionswithEDTAstandardsolution,thenacidifiethesolutiontopH10andcontinuetitratingmagnesiumionswithEDTA.Eglish1、氧化钙的测定（1）方法原理在pH=12~13的碱性溶液中，以三乙醇胺为掩蔽剂，用钙黄绿素-甲基百里香酚蓝-酚酞（CMP）混合指示剂，用EDTA标准溶液滴定。

该法在国家标准中列为基准法。一、EDTA配位滴定法中文1、Determinationofcalciumoxide(1)Methodprinciple

InanalkalinesolutionwithpHrangingfrom12to13,triethanolamineisusedasamaskingagent,andamixedindicatorofcalciumyellowgreenmethylthymolbluephenolphthalein(CMP)isusedasanindicator,titratewithEDTAstandardsolution.

Thislawislistedasabenchmarkmethodinnationalstandards.一、EDTAcoordinationtitrationmethodEglish（2）结果计算中文(2)ResultcalculationCaO%c--ConcentrationofEDTAstandardsolution,mol/LV--VolumeofEDTAstandardsolution,mLM--MolarmassofCaO,g/molm--Massofthesample,gEglish（3）注意事项硅的干扰与消除在不分离硅的试液中测定钙时，在强碱性溶液中会生成硅酸钙，使钙的测定结果偏低。可将试液调为酸性后，加入一定量的KF溶液，并搅拌和放置2min以上，硅会转变为氟硅酸。当用KOH将溶液碱化时，氟硅酸慢慢转化为非聚合状态的硅酸，在30min内不会生成硅酸钙沉淀。H2SiO3+6H++6F-=H2SiF6+3H2OH2SiF6+6OH-=H2SiO3+6F-+3H2O中文（3）NoteInterferenceandeliminationofsiliconWhenmeasuringcalciuminatestsolutionwithoutseparatingsilicon,calciumsilicatewillbegeneratedinastrongalkalinesolution,resultinginalowerdeterminationresultofcalcium.Afteradjustingthetestsolutiontoacidic,addacertainamountofKFsolution,stirandletitstandformorethan2minutes,andthesiliconwilltransformintofluorosilicicacid.WhenthesolutionisalkalizedwithKOH,fluorosilicicacidslowlytransformsintoanonpolymerizedstateofsilicicacid,withoutgeneratingcalciumsilicateprecipitationwithin30minutes.H2SiO3+6H++6F-=H2SiF6+3H2OH2SiF6+6OH-=H2SiO3+6F-+3H2OEglish（3）注意事项铁、铝、钛的干扰与消除铁、铝、钛的干扰可用三乙醇胺掩蔽，少量锰与三乙醇胺也能生成绿色配合物而被掩蔽。加入三乙醇胺的量一般为5mL，但当测定高铁试样时应增加中10mL并充分搅拌，加入后溶液应呈酸性，如溶液变浑应立即以盐酸调至酸性并放置几分钟。中文（3）NoteInterferenceandeliminationofiron,aluminum,andtitaniumTheinterferenceofiron,aluminum,andtitaniumcanbemaskedbytriethanolamine,andasmallamountofmanganeseandtriethanolaminecanalsoformgreencomplexesandbemasked.Theamountoftriethanolamineaddedisgenerally5mL,butwhenmeasuringthehigh-speedironsample,anadditional10mLshouldbeaddedandstirredthoroughly.Afteraddition,thesolutionshouldbeacidic.Ifthesolutionbecomesturbid,itshouldbeimmediatelyadjustedtoacidicwithhydrochloricacidandlefttostandforafewminutes.Eglish（3）注意事项银、镁的干扰与消除使用银坩埚熔样时会引入一定量的银离子，但如采用CMP作指示剂，即使有1mg~5mg的银存在对钙的测定也无干扰，镁共存量高时终点也无返色现象。但加入CMP的量不宜过多，否则终点呈深红色，变化不敏锐。中文（3）NoteInterferenceandeliminationofsilverandmagnesiumWhenusingasilvercrucibletomeltthesample,acertainamountofsilverionswillbeintroduced.However,ifCMPisusedasanindicator,eventhepresenceof1mg~5mgofsilverwillnotinterferewiththedeterminationofcalcium,andtherewillbenocolorreturnattheendpointwhenthemagnesiumcostockishigh.ButtheamountofCMPaddedshouldnotbetoomuch,otherwisetheendpointwillbedarkredandthechangeswillnotbesensitive.Eglish（3）注意事项氢氧化镁沉淀吸附的干扰与消除滴定至近终点时应充分搅拌，使被氢氧化镁沉淀吸附的钙离子能释放出来与EDTA充分反应。在使用CMP指示剂时不能在光线直接照射下观察终点，应使光线从上向下照射。终点时应观察整个液层，至烧杯底部绿色荧光消失呈现红色即为终点。中文（3）NoteInterferenceandeliminationofadsorptionofmagnesiumhydroxideprecipitationWhentitratingtothenearendpoint,sufficientstirringshouldbeperformedtoallowthecalciumionsadsorbedbythemagnesiumhydroxideprecipitatetobereleasedandreactfullywithEDTA.WhenusingCMPindicators,theendpointshouldnotbeobservedunderdirectlightirradiation,andthelightshouldbedirectedfromtoptobottom.Attheendpoint,theentireliquidlayershouldbeobserveduntilthegreenfluorescenceatthebottomofthebeakerdisappearsandturnsred,whichistheendpoint.Eglish2、氧化镁的测定-配位滴定差减法一、EDTA配位滴定法（1）方法原理在pH=10的溶液中，以三乙醇胺、酒石酸钾钠为掩蔽剂，用酸性铬蓝钾-萘酚绿B（KB）混合指示剂，用EDTA标准溶液滴定，测定钙、镁含量，然后扣除氧化钙的含量即得氧化镁的含量。

当试样中MnO的含量在0.5%以上时，在盐酸羟胺存在下，测定钙、镁、锰总量，差减法求得氧化镁含量。中文2、Determinationofmagnesiumoxide-Coordinationtitrationsubtractionmethod一、EDTAcoo