《工业分析 Industrial Analysis》课件-硅钼蓝法测定钢铁中硅（双语）

项目六：钢铁分析任务六：钢铁中硅的测定硅钼蓝法测定钢铁中硅课程：工业分析中文Scenario6:SteelanalysisTask6:DeterminationofsiliconinsteelDeterminationofSiliconinSteelbySiliconMolybdenumBlueMethodCourse:IndustrialAnalysisEglish1、方法原理试样用稀酸溶解后，使硅转化为可溶性硅酸:3FeSi+l6HNO3=3Fe(NO3)3+3H4SiO4+7NO

+2H2OFeSi+H2SO4+4H2O=FeSO4+H4SiO4+3H2

中文1、MethodprincipleAfterdissolvingthesampleindiluteacid,thesiliconisconvertedintosolublesilica:3FeSi+l6HNO3=3Fe(NO3)3+3H4SiO4+7NO

+2H2OFeSi+H2SO4+4H2O=FeSO4+H4SiO4+3H2

Eglish加高锰酸钾氧化碳化物，再加亚硝酸钠还原过量的高锰酸钾，在弱酸性溶液中，加入钼酸，使其与H4SiO4反应生成氧化型的黄色硅钼杂多酸(硅钼黄)，在草酸的作用下，用硫酸亚铁铵将其还原为硅钼蓝:中文Addpotassiumpermanganatetooxidizecarbides,thenreduceexcesspotassiumpermanganatewithsodiumnitrite.Inaweaklyacidicsolution,addmolybdicacidtoreactwithH4SiO4toformanoxidizedyellowsiliconmolybdenumheteropolyacid(siliconmolybdenumyellow).Undertheactionofoxalicacid,reduceittosiliconmolybdenumbluewithammoniumferroussulfate:Measuretheabsorbanceofsiliconmolybdenumblueatawavelengthof810

nm.Thismethodisapplicabletothedeterminationof0.030-1.00%acidsolublesiliconcontentiniron,carbonsteel,andlowalloysteel.Eglish2、主要试剂纯铁（硅的含量小于0.002%）钼酸铵溶液（50g/L）草酸溶液(50g/L)硫酸亚铁铵溶液(60g/L)硅标准溶液(20

g/mL)中文2、MainreagentsPureiron(siliconcontentlessthan0.002%)Ammoniummolybdatesolution(50

g/L)Oxalicacidsolution(50

g/L)Ammoniumferroussulfatesolution(60

g/L)Siliconstandardsolution(20μg/mL)Eglish3、分析步骤称取试样0.1g左右，置于150mL烧杯中。加入30mL硫酸(1+17)，低温缓慢加热（不要煮沸）至试样完全溶解（并不断补充蒸发失去的水分）。煮沸，滴加高锰酸钾溶液（40g/L)至析出二氧化锰水合物沉淀。再煮沸约lmin，滴加亚硝酸钠溶液(100g/L)至试验溶液清亮，继续煮沸lmin～2min(如有沉淀或不溶残渣，趁热用中速滤纸过滤，用热水洗涤)。冷却至室温，将试验溶液移入100mL容量瓶中，用水稀释至刻度，混匀。中文3、AnalysisSteps

Weighapproximately0.1gofthesampleandplaceitina150

mLbeaker.Add30

mLofsulfuricacid(1+17)andheatslowlyatlowtemperature(donotboil)untilthesampleiscompletelydissolved(andcontinuouslyreplenishthelostwaterbyevaporation).Boilandaddpotassiumpermanganatesolution(40

g/L)dropwiseuntilmanganesedioxidehydrateprecipitates.Boilforabout1minute,addsodiumnitritesolution(100

g/L)dropwiseuntilthetestsolutionbecomesclear,andcontinueboilingfor1minuteto2minutes(ifthereisanyprecipitateorinsolubleresidue,filterwithmediumspeedfilterpaperwhilehotandwashwithhotwater).Cooltoroomtemperature,transferthetestsolutionintoa100

mLvolumetricflask,dilutewithwatertothemark,andmixwell.Eglish移取10.00mL上述试验溶液二份，分别置于50mL容量瓶中,一份作显色溶液用，一份作参比溶液用

显色溶液

:小心加入5.0mL钼酸铵溶液，混匀。放置15min或沸水浴中加热30s，加入l0mL的草酸溶液，混匀。待沉淀溶解后30s内，加入5.0mL的硫酸亚铁铵溶液，用水稀释至刻度，混匀。

参比溶液

:加入10.0mL草酸溶液、5.0mL钼酸铵溶液、5.0mL硫酸亚铁铵溶液，用水稀释至刻度，混匀。中文Transfertwopartsof10.00mLoftheaboveexperimentalsolutionandplacethemin50mLvolumetricflasks,onepartasthecolorimetricsolutionandtheotherpartasthereferencesolution:Colorsolution:Carefullyadd5.0mLofammoniummolybdatesolutionandmixwell.Placefor15minutesorheatinaboilingwaterbathfor30seconds,add10mLofoxalicacidsolution,andmixwell.Within30secondsaftertheprecipitationisdissolved,add5.0mLofammoniumferroussulfatesolution,dilutewithwatertothemark,andmixwell.Referencesolution:Add10.0mLoxalicacidsolution,5.0mLammoniummolybdatesolution,and5.0mLammoniumferroussulfatesolution,dilutewithwatertothemark,andmixwell.Eglish将显色溶液移入lcm吸收皿中，以参比溶液为参比，于分光光度计波长810nm处测量溶液的吸光度值。对没有此波长范围的光度计，可于680nm处测量。

用工作曲线法计算含量中文

Transferthecolorimetricsolutionintoa1cmabsorptiondishandmeasuretheabsorbancevalueofthesolutionatawavelengthof810

nmusingthereferencesolutionasthereference.Forphotometerswithoutthiswavelengthrange,theabsorbanceofthesolutioncanbemeasuredat680

nm.

CalculatecontentusingtheworkingcurvemethodEglish4、结果计算中文4、ResultcalculationIntheformula:M-Siliconcontentobtainedfromtheworkingcurve,μg;V-Volumeofthetestsolutiontaken,mL;V-Totalvolumeoftestsolution,mLM-Samplesize,g.Eglish5、注意事项选该参比液的目的清除草酸铁的黄色(虽为淡黄色但也有影响)

方法技巧在于：先加草酸，破坏硅钼杂多酸Si显色使用H2C2O4注意硅钼黄也能进一步被H2C2O4分解因此加入H2C2O4，待钼酸铁（黄色）↓溶解后，立即（半分钟内）加入FeSO4还原之.中文5、NoteThepurposeofselectingthisreferencesolutionCleartheyellowcolorofironoxalate(althoughitislightyellow,italsohasanimpact)Elimination:Firstaddoxalicacidtodisruptthecolordevelopmentofsiliconmolybdenumheteropolyacid

Attentionshouldbe