《工业分析 Industrial Analysis》课件-钾肥分析（双语）

项目四：肥料分析任务四：钾肥分析钾肥分析课程：工业分析中文Scenario4:FertilizerAnalysisTask4:PotassiumfertilizeranalysisPotassiumfertilizeranalysisCourse:IndustrialAnalysisEglish一、钾肥种类中文一、TypesofpotassiumfertilizersPotassiumfertilizerisdividedintotwocategories:naturalpotassiumfertilizerandchemicalpotassiumfertilizer.Thesumofwater-solubleandweaklyacidsolublepotassiumsaltsinpotassiumfertilizeriscalledeffectivepotassium.Thesumofavailablepotassiumandinsolublepotassiumsaltsiscalledtotalpotassium.ThepotassiumcontentofpotassiumfertilizerisexpressedasK2O.Whenmeasuringeffectivepotassium,asamplesolutionisusuallypreparedbydissolvingitinhotwater;Ifthesamplecontainsweaklyacidsolublepotassiumsalt,dissolvetheavailablepotassiuminhotwaterwithasmallamountofhydrochloricacidadded.Whenmeasuringthetotalpotassiumcontent,thesamplesolutionisgenerallypreparedbystrongaciddissolutionoralkalimeltingmethod.Eglish二、钾肥分析方法

钾肥中有效钾的测定方法有四苯硼酸钾重量法、四苯硼酸钠容量法和火焰光度法。四苯硼酸钾重量法和四苯硼酸钠容量法简便、准确、快速，适用于含氧化钾量较高的钾肥测定。当试样中含氧化钾小于2%时，采用火焰光度法测定。中文二、Analysismethodsforpotassiumfertilizer

Themethodsfordeterminingeffectivepotassiuminpotassiumfertilizersincludepotassiumtetraphenylborategravimetricmethod,sodiumtetraphenylboratevolumetricmethod,andflamephotometry.

Thepotassiumtetraphenylborategravimetricmethodandthesodiumtetraphenylboratevolumetricmethodaresimple,accurate,andfast,suitableforthedeterminationofpotassiumfertilizerswithhighpotassiumoxidecontent.Whenthecontentofpotassiumoxideinthesampleislessthan2%,flamephotometryisusedformeasurement.Eglish（1）方法原理：在碱性条件下加热消除试样溶液中铵离子的干扰，加入乙二胺四乙酸二钠(EDTA)螯合其他微量阳离子，以消除干扰分析结果的阳离子。在微碱性介质中，四苯硼酸钠与钾反应生成四苯硼酸钾沉淀，过滤、干燥沉淀并称量。1、四苯硼酸钾重量法中文(1)Methodprinciple:Heatunderalkalineconditionstoeliminatetheinterferenceofammoniumionsinthesamplesolution,andadddisodiumethylenediaminetetraacetate(EDTA)tochelateothertracecationstoeliminatetheinterferenceofcationsintheanalysisresults.Inaslightlyalkalinemedium,sodiumtetraphenylboratereactswithpotassiumtoformpotassiumtetraphenylborateprecipitate,whichisfiltered,dried,andweighed.1、potassiumtetraphenylborategravimetricmethodwhiteEglish（2）结果计算氧化钾(K2O)的含量w1以质量分数%表示，按下式计算：中文（2）resultcalculation

Thecontentofpotassiumoxide(K2O)w1isexpressedasamassfraction%,andiscalculatedusingthefollowingformula:Eglish（3）实验步骤

移取一定量溶液，加入EDTA溶液及酚酞指示液，在搅拌下逐滴加入氢氧化钠溶液至红色出现并过量1mL。加热微沸15min(此时溶液应保持红色)。在搅拌下逐滴加入四苯硼钠溶液，在流水中迅速冷却至室温并放置15min。先过滤上层清液，再用洗涤液转移沉淀至过滤器中，用洗涤液洗涤沉淀，干燥称量。中文（3）Procedure

Takeacertainamountofsamplesolution,addEDTAsolutionandphenolphthaleinindicatorsolution,andaddsodiumhydroxidesolutiondropwisewhilestirringuntilredappearsand1mLofexcesssodiumhydroxidesolutionisadded.Heatandslightlyboilfor15minutes(atthistime,thesolutionshouldremainred).Addsodiumtetraphenylboratesolutiondropwisewhilestirring,rapidlycooltoroomtemperatureinflowingwater,andletitstandfor15minutes.Firstfiltertheupperclearliquid,thentransfertheprecipitatetothefilterwithwashingsolution.Washtheprecipitatewithwashingsolution,dryit,andweighit.Eglish（1）方法原理在碱性条件下加热消除试样溶液中铵离子的干扰，加入乙二胺四乙酸二钠(EDTA)消除其他阳离子的干扰，在微碱性介质中，以过量的四苯硼酸钠与钾反应生成四苯硼酸钾沉淀，过滤，滤液中过量的四苯硼酸钠以达旦黄作指示剂，用季铵盐返滴至溶液由黄变成明显的粉红色2、四苯硼酸钠容量法中文(1)MethodprincipleHeatunderalkalineconditionstoeliminatetheinterferenceofammoniumionsinthesamplesolution,andadddisodiumethylenediaminetetraacetate(EDTA)toeliminatetheinterferenceofothercations.Inaslightlyalkalinemedium,excesssodiumtetraphenylboratereactswithpotassiumtoformpotassiumtetraphenylborateprecipitate,whichisfiltered.Finally,usingdanhuangasanindicator,theexcesssodiumtetraphenylborateistitratedbackwithquaternaryammoniumsaltuntilthesolutionchangesfromyellowtoaclearpinkcolor2、sodiumtetraphenylboratevolumetricmethodEglish其化学反应为：B(C6H5)4-＋K+＝KB(C6H5)4↓Br[N(CH3)3·C16H33]＋NaB(C6H5)4＝B(C6H5)4·N(CH3)3C16H33↓＋NaBr中文Itschemicalreactionis:B(C6H5)4-＋K+＝KB(C6H5)4↓Br[N(CH3)3·C16H33]＋NaB(C6H5)4＝B(C6H5)4·N(CH3)3C16H33↓＋NaBrEglish(2)方法讨论

钾肥中常见的杂质有钙、镁、铝、铁等硫酸盐和磷酸盐，虽与四苯硼酸钠不反应，但滴定体系在碱性溶液中进行，可能会生成氢氧化物、磷酸盐等沉淀，因吸附作用影响滴定，故加EDTA掩蔽。中文(2)Methoddiscussion

Commonimpuritiesinpotassiumfertilizerincludesulfatesandphosphatessuchascalcium,magnesium,aluminum,andiron.Theydonotreactwithsodiumtetraphenylborate.Becausetitrationiscarriedoutinanalkalinesolution,thesesaltsubstancesmayformprecipitatessuchashydroxidesandphosphates,whichaffecttitrationduetotheadsorptioneffectoftheprecipitate.Therefore,EDTAshouldbeaddedtomasktheseions.Eglish3、火焰光度法（1）方法原理试样经硫酸-过氧化氢消煮，使待测液在火焰高温激发下辐射出钾元素的特征光谱，其强度与溶液中钾的浓度成正比，从钾标准溶液所作的工作曲线上即可查出待测液的钾浓度。（2）结果计算总钾含量(K2O)计)的质量百分数。中文3、Flamephotometry(1)MethodprincipleAfterthesampleisdigestedwithsulfuricacidhydrogenperoxide,thesolutiontobetestedisexcitedbyahigh-temperatureflameandemitsacharacteristicspectrumofpotassiumelement.Theintensityofthespectrallinesisproportion