Causes of electroplating anode slime and application of electroplating auxiliary anode and electroplating insoluble anode
MMO insoluble titanium anode for electroplating
MMOinsolubletitaniumanodeforelectroplatingFirst,iridium-tantalum(Ir-Ta)coatedelectrodeOxygen-resistantelectrodeismainlyusedforoxygenevolutionreaction,especiallysuitableforacidelectrolyte,suchasacertainconcentrationofsulfuricacidelectrolyte,theoxygenisverylow,canbeusedforoxygenreleaseelectrolysis,alsoresistanttothecorrosionofchlorine,canbeusedforoxygenreleaseandchlorinereleaseelectrolysisSuchasseawaterelectrolysis,etc.Itisanelectrodematerialwithgoodoxygenreleasereactioninacidicmedium.Inthisenvironment,theavailableelectrodematerialsarelimited.Thecoatedelectrodehasbeenusedinorganicelectrolysis,suchascysteine,glyoxylicacid,succinicacid,etc.,whichcanbeusedforCr3+﹢→Cr6+electrolysisofindirectoxidationoforganicelectrolysis,andsewagetreatmentisusedtooxidizeorganicandtoxicsubstancesinwater.SuchasCN-transformation.Itcanalsobeusedintheelectroplatingindustryasauxiliaryelectrodes,suchasauxiliaryanodesforCrplating,auxiliaryanodesforelectrolyticcopper,andthelike. two,Ruthenium-titanium-iridium(Ru-Ti-Ir)ternarycoatingelectrodeThecoatedelectrodeisusedforelectrolytescontaininghighhydroxideradicals,isresistanttooxygencorrosion,andissuitableforionmembraneelectrolysis.Coatingindex:1.Thedischargepotentialis1.18volts(S.C.E)atacurrentdensityof4000A/m2.2.Strengthenedlife(coatingweightlossmethod)1.02mv/4hours4cm2,theservicelifeisguaranteedformorethan5years,andithasbeenappliedtoindustriallargeelectrictanks. Three,ruthenium-titanium-tin(Ru-Ti-Sn)ternarycoatingelectrode ThetechnologyhasbeensuccessfullydevelopedandhaswontheScienceandTechnologyProgressAwardoftheMinistryofChemicalIndustry.Coatingcharacteristics: 1.Thechlorineevolutionpotentialislowandtheoverpotentialissmall.At2000A/m2currentdensity,thechlorinegasdischargepotentialisnotgreaterthan1.12V,andtheoverpotentialislessthan20mv. 2.Thepolarizationrateislessthan30mv/10unitcurrentdensity. 3.Longerlife-span:0.5NH2SO4,1A/cm2currentdensity,lifespanisgreaterthan1500minutes. Theabovethreeindicatorsarebetterthantheindustryspecifiedindicators(industrialindicatorsare:potential1.13volts,polarizationrate40mv/10unitcurrentdensity,enhancedlifeisgreaterthan1000minutes). Fourth,titaniumplatinum(Ti/Pt)coatedelectrodeBasemetal:Gr1,Gr2,TA1,TA2 Workingcurrentrange:<2000A/m2 Temperaturerange:<80℃ Coatedmetal:Pt(99.99%) Shape:plate,tube,etc.Technicalcharacteristics:Itisaninsolubleanode.Theplatinumplatinglayerisfirmlycombinedwiththetitanium-basedsubstrateandtheuseperformanceisstable.Itcanreplacepuregoldandpureplatinumanodesforgoldandotherpreciousmetalplatingtanks.Application:Acidandalkalineplatingsolution Five,titanium-basedmaterialsprocessingrequirements:Surfaceroughness:Thereisnorelevantstandardforthisitem,therougherthebetter.Platenetanodesurfaceflatness:thickness1.5ormore≤±0.5mm/M,thickness1.0orless≥±1.0mm/M,Tubeanodestraightness:wallthickness1.5mmabove±0.5mm/M,wallthickness1.5mmbelow±1.0mm/MBlankingtoleranceofplateprocessedparts:theminimumcanbecontrolledwithin±0.1mm,andthegeneraldeliverytoleranceiswithin±0.5mm Six,theuseoftitaniumanodeproducts: DSAisnotatrueinsolubleanode,it'sjustthattheconsumptionrateislow.Dependingontheapplicationindustryandthespecificuseenvironment,ourcompanycanguaranteeaguaranteedserviceliferangingfrom0.5-50years.1.Withinthenormalworkingcurrentdensityof2000A/m²,theexcessivecurrentwillcausethereactiontobetoointenseandshortentheanodelife;2.Theelectrolytemustnotcontaincyanideandfluorideions.Theseimpuritiescanseverelycorrodethetitaniummatrix;3.Theanodeandanodepoledistancecanbesetaccordingtothespecificsituation,generally5-25mm.Generallyspeaking,thepoledistanceincreasesthepowerconsumption,andatthesametime,itshouldnotbetoosmall,otherwisethecathodescalegeneratedonthecathodesurfaceislikelytocausetheshortcircuitoftheplate;4.Itisstrictlyforbiddentouselead.Oncethepreciousmetaloxidecoatingisusedasacathode,areductionreactionoccursonthesurface,anditiseasytobeconvertedintoametalelement,whichcannoteffectivelycombinewiththetitaniumbase,causingthecoatingtofalloff.Considerperiodicallyaddingacidtocleanthesurfaceoftheplate.,5.Thetemperatureoftheelectrolyteshouldnotbetoohigh,theidealtemperatureis25-40°C.6.Rinsethesurfaceoftheplatewithcleanwaterduringshutdown.Itshouldnotbeimmersedinthesolutionforalongtimeafterpoweroff.Ifpossible,itisbesttomaintainasmallcurrentof2-5Atomeetthecycletoprotecttheplate.7,installationandhandlingneedtobecareful,thecoatingsurfacemustnotbescratched,otherwiselocalcorrosionwillsoon.
What does TOD, TOC, BOD, COD mean in industrial wastewater treatment? What is the connection between them?
WhatdoesTOD,TOC,BOD,CODmeaninindustrialwastewatertreatment?Whatistheconnectionbetweenthem?Therearetwotypesofcomprehensiveindicatorsforthecontentoforganicmatterinwater.Oneisanindicatorthatisequivalenttotheamountoforganicmatterinwater(O2),suchasBOD,chemicaloxygendemand(COD),andtotaloxygendemand(TOD).;Theotherisanindicatorexpressedincarbon(c),suchastotalorganiccarbonTOC.Forthesamekindofsewage,thevaluesoftheseindicatorsaregenerallydifferent,andtheorderofthevaluesisTOD>COD>BOD5>TOC. 1.TOD Totaloxygendemand(TOD)referstotheamountofoxygenrequiredforreducingsubstancesinwatertobecomestableoxidesaftercombustionathightemperatures.Theresultsareexpressedinmg/L.TheTODvaluecanreflecttheoxygenrequiredtoconsumealmostallorganicmatterinwater(includingcarbonC,hydrogenH,oxygenO,nitrogenN,phosphorusP,sulfurSandothercomponents)aftercombustionintoCO2,H2O,NOx,SO2,etc.theamount. 2.TOC TotalorganiccarbonTOCisacomprehensiveindicatorthatindirectlyexpressesthecontentoforganicmatterinwater.Thedataitshowsisthetotalcarboncontentoforganicmatterinsewage.Theunitisexpressedinmg/Lofcarbon(c).TheTOCofgeneralurbansewagecanreach200mg/L,theTOCrangeofindustrialsewageiswide,thehighestcanreachtensofthousandsofmg/L,andtheTOCofsewageaftersecondarybiologicaltreatment-generally<50mg/L. 3．BODBOD Biochemicaloxygendemandiscalledbiochemicaloxygendemand,whichisabbreviatedasBOD.Itmeanstheamountofdissolvedoxygenconsumedduringthebiochemicaloxidationprocessofaerobicmicroorganismstodecomposeorganicmatterinwateratatemperatureof20°Candaerobicconditions.Theamountofoxygenrequiredtostabilizebiodegradableorganicsinwater,theunitismg/L.BODincludesnotonlytheamountofoxygenconsumedbythegrowthandreproductionofaerobicmicroorganismsinthewater,butalsotheamountofoxygenconsumedbyreducinginorganicsubstancessuchassulfidesandferrousiron,buttheproportionofthispartisusuallysmall. Undernaturalconditionsat20°C,thetimerequiredfortheorganicmattertooxidizetothenitrationstage,thatis,toachievecompletedecompositionstability,ismorethan100d.However,BOD20,whichiscommonlyusedat20°Cfor20d,approximatelyrepresentsthecompleteBOD.Itisstillconsideredthatthetimeof20distoolonginproductionandapplication.Generally,theBOD5ofBOD5of5dat20℃isusedasanindextomeasurethecontentoforganicmatterinsewage. 4.COD Chemicaloxygendemand(COD)referstotheamountofoxygenconvertedintooxygenbytheconsumptionoforganicsubstancesinwaterandstrongoxidantsundercertainconditions,inmg/Lofoxygen.Whenpotassiumdichromateisusedastheoxidant,almostalloftheorganicmatterinthewater(90%to95%)canbeoxidized.Atthistime,theamountofoxygenconsumedbytheoxidantconvertedintooxygenisgenerallycalledchemicaloxygendemand,whichisoftenabbreviatedasCODcr.TheCODcrvalueofwastewaterincludesnotonlytheoxygenconsumptionofalmostallorganicsubstancesinthewater,butalsotheoxygenconsumptionofreducinginorganicsubstancessuchasnitrites,ferroussalts,andsulfidesinthewater. 5.TherelationshipbetweenBOD5andCOD BOD5isnotonlyanimportantwaterqualityindicator,butalsoanextremelyimportantcontrolparameterinthebiologicaltreatmentprocessofsewage.However,duetothelongmeasurementtime(5d),itcannotreflectandguidetheoperationofthesewagetreatmentdeviceintime,andcanonlybeusedforprocesseffectevaluationandlong-termWangYiregulation.Foraspecificsewagetreatmentplant,thecorrelationbetweenBOD5andCODcanbeestablished,andaroughestimateoftheCOD5valueofCODisusedtoguidetheadjustmentofthetreatmentprocess.Sometimes,becausesomeproductionwastewaterdoesnothavetheconditionsforthegrowthandreproductionofmicroorganisms(suchasthepresenceoftoxicorganicsubstances),itsBOD5valuecannotbeaccuratelydetermined. Thechemicaloxygendemand(COD)valueofsewagecanbeusedtoaccuratelydeterminethecontentoforganicmatterinwater,butCODcannotdistinguishbetweenbiodegradableorganicmatterandnon-biodegradableorganicmatter.PeopleareusedtomeasuringtheBOD5/CODofsewagetodetermineitsbiodegradability.ItisgenerallybelievedthatsewagecanbetreatedbybiodegradationifitsBOD5/CODisgreaterthan0.3.IftheBOD5/CODofsewageislowerthan0.2.Onlyothermethodscanbeconsideredforprocessing. TheCODvalueofthechemicaloxygendemandisgenerallyhigherthantheBOD5valueofthebiochemicaloxygendemand,andthedifferencebetweenthemcanroughlyreflecttheorganicmattercontentinthesewagethatcannotbedegradedbymicroorganisms.Forsewagewithrelativelyfixedpollutantcomponents,thereisgenerallyacertainproportionalrelationshipbetweenCODandBOD5,whichcanbecalculatedfromeachother.Inaddition,themeasurementofCODtakeslesstime,andthenationalstandardmethodfor2hoursofrefluxisusedtoperformthetest.Ittakesonly3to4hoursfromthesamplingtotheresult,andtheBOD5valuetakes5days.CODisoftenusedasacontrolindicator. Inordertoguidetheproductionandoperationassoonaspossible,somesewagetreatmentplantshavealsoestablishedenterprisestandardsformeasuringCODfor5minutesatreflux.Althoughthemeasuredresultsaresomewhatdifferentfromthenationalstandardmethod,theerrorsaresystematicerrorsandtheresultsofcontinuousmonitoringcanaccuratelyreflectthewaterquality.Theactualchangetrendofthemeasurementtimecanbereducedtolessthan1h,whichprovidesatimeguaranteeforti
The principle of forced current cathodic protection and the relationship between auxiliary anode corrosion rate and current density
Theprincipleofforcedcurrentcathodicprotectionandtherelationshipbetweenauxiliaryanodecorrosionrateandcurrentdensity First,theprincipleofforcedcurrentcathodicprotection Thetraditionalmetalanti-corrosionmethodismainlyisolationandanti-corrosion,thatis,toisolatemetalfromcorrosivemedium.Specificmeasuresincludecoatings,coatings,andplating.Anothermethodistochooseacorrosion-resistantmetal,suchasstainlesssteel,copper,titanium,etc.;orothermaterialssuchasplastic,fiberglass,etc.ifpossible. However,becausethecorrosiveenvironmentisalmostubiquitous,theformsofcorrosionarealsovarious.Asingleanti-corrosionmeasureoftencannoteffectivelycontrolmetalcorrosion,especiallyelectrochemicalcorrosion.Onceametalstructureisformedwithacorrodedbattery,theanoderegionhasamuchsmallerareathanthecathoderegion,andthecorrosionrateisextremelyfast.Atthistime,themetalsurfaceisnotuniformcorrosion,butpittingcorrosion.Almostallundergroundoilandgaspipelines,storagetanks,andvariouscontainersandequipmentcontainingelectrolytesleakduetopittingcorrosion. Cathodicprotectionistheuseoftheprincipleofcorrodingthebattery.Themetalstructuretobeprotectedisusedasthecathode,andtheanodeiscontinuouslysuppliedwithelectronsthroughtheanode.Thestructureisfirstpolarizedandtheelectronsareenrichedonthesurfaceofthestructure,makingitdifficulttogenerateions.Greatlyslowdowntherateofcorrosionofthestructure.Cathodicprotectionisroughlydividedintotwotypes:sacrificialanodemethodandappliedcurrentmethod(forcedcurrent).Theanodesusedinthesacrificialanodemethodaremagnesium,aluminum,andzincactivemetalalloyanodes;theanodesusedintheforcedcurrentmethodareMMO(mixedmetaloxide)titanium-basedcoatinganodesasauxiliaryanodes.Theforcedcurrentmethod(externalcurrentmethod)istoapplyacathodiccurrenttotheprotectedstructureandananodecurrenttotheauxiliaryanodetoformacorrodedbattery.Themetalstructureisprotectedonthesameprinciple.Itiseconomicalandhasalonganodeservicelifewhenimplementinglarge-scalefieldcathodicprotection. Externalcurrentcathodicprotectionauxiliaryanode Second,therelationshipbetweenauxiliaryanodecorrosionrateandcurrentdensity Relationshipbetweenanodecurrentdensityandcoatingconsumption Relationshipbetweenanodecurrentdensityandlife Asshowninthefigureabove,astheanodecurrentdensityincreases,theconsumptionrateofthecoatingalsoincreases,andtheservicelifealsodecreases.
