EPA METHOD 9010C Total and Amenable Cyanide- Distillation

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1、METHOD9010CTOTALANDAMENABLECYANIDE:DISTILLATION1.0SCOPEANDAPPLICATION1.1Thismethodisareflux-distillationprocedureusedtoextractsolublecyanidesaltsandmanyinsolublecyanidecomplexesfromwastesandleachates.Itisbasedonthedecompositionofnearlyallcyanidesbyaref

2、luxdistillationprocedureusingastrongacidandamagnesiumcatalyst.Cyanide,intheformofhydrocyanicacid(HCN)ispurgedfromthesampleandcapturedintoanalkalinescrubbersolution.TheconcentrationofcyanideinthescrubbersolutionisthendeterminedbyMethod9014orMethod9213.T

3、hismethodmaybeusedasareflux-distillationprocedureforbothtotalcyanideandcyanideamenabletochlorination.The"reactive"cyanidecontentofawasteisnotdeterminedbythismethod.Referto40CFR261.23forinformationonthecharacteristicofreactivity.1.2Thismethodwasdesigned

4、toaddresstheproblemof"trace"analyses(<1000ppm).Themethodmayalsobeusedfor"minor"(1000ppm-10,000ppm)and"major"(>10,000ppm)analysesbyadaptingtheappropriatesampledilution.However,theamountofsodiumhydroxideinthestandardsandthesampleanalyzedmustbethesame.2.0

5、SUMMARYOFMETHOD2.1Thecyanide,ashydrocyanicacid(HCN),isreleasedfromsamplescontainingcyanidebymeansofareflux-distillationoperationunderacidicconditionsandabsorbedinascrubbercontainingsodiumhydroxidesolution.Thecyanideconcentrationintheabsorbingsolutionis

6、thendeterminedcolorimetricallyortitrametricallybyMethod9014orbyion-selectiveelectrodebyMethod9213.3.0INTERFERENCES3.1Interferencesareeliminatedorreducedbyusingthedistillationprocedure.ChlorineandsulfideareinterferencesinMethod9010.3.2Oxidizingagentssuc

7、haschlorinedecomposemostcyanides.Chlorineinterferencescanberemovedbyaddinganexcessofsodiumarsenitetothewastepriortopreservationandstorageofthesampletoreducethechlorinetochloridewhichdoesnotinterfere.3.3Sulfideinterferencecanberemovedbyaddinganexcessofb

8、ismuthnitratetothewaste(toprecipitatethesulfide)beforedistillation.Samplesthatcontainhydrogensulfide,metalsulfides,orothercompoundsthatmayproducehydrogensulfideduringthedistillationshouldbetreatedbytheadditionofbismuthnitrate.3.4Highres