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Rong Zhu Theory and Practice of CO Utilization 2 in Steelmaking Theory and Practice of CO Utilization 2 in Steelmaking Rong Zhu Theory and Practice of CO 2 Utilization in Steelmaking RongZhu SchoolofMetallurgicalandEcological Engineering UniversityofScienceandTechnology Beijing Beijing,China ISBN 978-981-19-2544-3 ISBN 978-981-19-2545-0 (eBook) https://doi.org/10.1007/978-981-19-2545-0 JointlypublishedwithSciencePress TheprinteditionisnotforsaleinChina(Mainland).CustomersfromChina(Mainland)pleaseorderthe printbookfrom:SciencePress. ©SciencePress2023 Thisworkissubjecttocopyright.AllrightsaresolelyandexclusivelylicensedbythePublisher,whether thewholeorpartofthematerialisconcerned,specificallytherightsofreprinting,reuseofillustrations, recitation,broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionor informationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Preface In 1983, I graduated from Jiangxi Institute of Metallurgy (Jiangxi University of Science and Technology) to work at the Jiangxi Steel Plant (Xinyu Iron & Steel Group Co., Ltd.), where I successively served as a foreman, furnace chief, shift leader,andworkshopdirector.In1990,IwasadmittedtotheUniversityofScience and Technology Beijing (USTB) to study for a Master’s degree in iron and steel metallurgy.In1996,IobtainedmydoctorateandbecamealectureratUSTB.Ihave beenengagedintheteachingandresearchofsteelmakingformorethan20years. The origin of “Carbon Dioxide Steelmaking Theory and Practice” was brought about, thanks to questions that a student asked in class: “Why does top blowing oxygenproducedustinthesteelmakingprocess?Canitnotproduceorreducesmoke anddust?”Generally,themainreasonfortheproductionofdustinthesteelmaking processisthattheoxygen(O )blowinggivesoffalargeamountofheatandforms 2 ahigh-temperaturefirepointareawithatemperatureintherangeof2500°C–3000 °Clocally,whichcausesalargeamountofevaporationofmetaliron,asitsboiling point is around 2700 °C, the vapor of which reacts with the excess O above the 2 molten pool to generate a large amount of fine dust containing iron oxide (FeO), whichisdischargedwiththehigh-temperaturefluegas.Asforthequestion“canit notproduceorreducesmokeanddust?”,thisisaverydifficultquestiontoanswer.It isanewideatocontroltheproductionofdustfromthesourceandthisisanareathat hasnotyetbeenstudied,whichhasgreatlyinspiredmyresearchenthusiasm.After reviewingtherelevantliteraturepublishedbothathomeandabroad,Icameacrossa fewreportsonhowtoreducethegenerationofdustinsteelmakingfromthesource asidefromreducingtheintensityoftheO supplyandusingabottomblowingO 2 2 process. Since O blowing can produce a fire spot area with a high temperature, can 2 the temperature of the steelmaking fire spot area be reduced without affecting the smeltingrhythm?Afterponderingandexperimenting,Itriedtoreducethetemper- atureoftheO blowingfirespotareausingphysicalandchemicalcoolingmethods, 2 bymixingpowderorgaswiththeoxygen,andfinallyfoundthatonlycarbondioxide (CO )hasthecharacteristicstoachievethisaim.Thetemperatureofthesteelmaking 2 firespotcanbereducedby300°C–400°C,andthedustcanbereducedby5%–10% v vi Preface byadding5%CO intotheO .Therelatedresearchwascompletedin1,30,and300 2 2 tconverters,whichledtothisfantasticideabeingproved. Duringtheindustrialdemonstrationofthistechnique,itwasfoundthatCO can 2 increasethetotalamountofconvertergasandtheconcentrationofcarbonmonoxide (CO) in the converter gas and reduce the FeO content in the final slag as well as the oxygen, nitrogen, and phosphorus content in the molten steel. Based on these findings,themechanismandengineeringapplicationsofCO insteelmakingwere 2 studied. With the support of the National Natural Science Foundation of China, the NationalScienceandTechnologySupportPlanofChina,andschoolenterprisecoop- eration projects, the study on the basic theory and industrial demonstration of the applicationofCO insteelmakingwascarriedout,coveringthebasicoxygenfurnace, 2 electricarcfurnace(EAF),ladlefurnace,vacuumdegassingfurnace,andRheinstahl– Heraeusprocess.Alargenumberofindustrialtestshavebeencompleted,whichhas accumulateddatatowardindustrialapplication. Thisbookisthefirstacademicmonographeitherathomeorabroadontheappli- cationofCO inthesteelmakingfield.Inthisbook,themechanismoftheapplication 2 ofCO insteelmakingisanalyzedbylookingatthethermodynamicsandkineticsof 2 thereactionsofCO withtheelementspresentinmoltensteel.Thethermodynamic 2 conditionsofthereactionsofCO withsilicon,manganese,phosphorus,chromium, 2 nickel,vanadium,andotherelementswerecalculatedandanalyzedusingtheFact- Sagethermodynamicsoftware,andtheselectiveoxidationlawoftheabovemultiple elements by CO was also analyzed. In terms of kinetics, the interfacial reaction 2 mechanismofCO wasanalyzedviagasisotopeexchangetechnology,andtheO 2 2 transferprocessandtransferratebetweentheCO ,slag,andsteelwerestudied.In 2 termsofmaterialsandenergybalance,howtousethehigh-temperaturecharacter- istics of CO to control the temperature of the molten pool, improve the reaction 2 conditions of molten iron, reduce the evaporation of molten iron, and reduce the amountofsteelmakingdustwereintroduced.Basedontheexperimentaldata,theo- retical models of unit operation for the application of CO in steelmaking were 2 established,includingdecarburization,denitrification,dephosphorization,decarbur- izationandchromiumretention,vanadiumextraction,andcarbonpreservation,and thesetheoreticalmodelswereappliedtothesteelmakingproductionprocess,which isanimportantstepingoingfromtheorytopractice.Theaboveresearchworkhas openedupanewsolutionforenergysavingandliquidsteelcleaningintheironand steelproductionprocess,andrepresentsprogressinsteelmakingtechnology. The teachers who participated in the writing of this book were Hu Xiaojun (Sect. 3.1.2, Part 1 of Sect. 3.2.2), Lv Ming (Sect. 4.2), Li Hong (Chap. 6), and WangHaijuan(Chap.7).TheremainingchapterswerecompletedbyZhuRong.At thesametime,IwouldliketothankLiuRunzao,DongKai,WeiGuangsheng,Han Baochen,andWuWenhefortheircontribution.Theauthorsexpresstheirgreatrespect toFujianSansteel(Group)Co.,Ltd.,XiningSpecialSteelCo.,Ltd.,ShougangJing- tangIronandSteelCo.,Ltd.,TianjinTianguanSpecialSteelCo.,Ltd.,BaoshanIron andSteelCo.,Ltd.,NanjingIronandSteelCo.,Ltd.,andBeijingKemiRongcheng EnergyTechnologyCo.,Ltd. Preface vii Itisgratifyingthatironandsteelenterprisesarepayingincreasinglymoreatten- tion to the application of CO in the steel production process in China, with the 2 national attention focused on achieving a reduction in CO emissions.Atthe time 2 ofpublicationofthisbook,thistechnicalinventionhasbeenindustriallyappliedin converterandEAFsteelmaking.InMay2018,theChinaSocietyofMetalsagreedthat theoverallachievementsofthistechnologicalinventionhavereachedinternationally leadinglevels. Thisbookisrichincontent,focusingontherelationshipsbetweenmoderndetec- tion technology, metallurgical physical chemistry, and the steelmaking process. A large amount of experimental data is featured in this book, which describes the improving of the thermodynamic and kinetic theories of the steelmaking process, andservesasaguidefortheengineeringapplicationofCO insteelmaking. 2 ThepublicationofthisbookissupportedbythekeyprojectofNSFCandtheState Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing,towhomIthank. As ever, there may be some unavoidable errors in this work, so I am open to receivingconstructivecriticismandwelcomeanydialoguefrominterestedreaders regardingthismatter. Beijing,China RongZhu Contents 1 Introduction ................................................... 1 1.1 CurrentStatusofCO Emissions ............................. 1 2 1.2 ResearchonCO RecoveryTechnology ....................... 4 2 1.2.1 SolventAbsorptionMethods ........................... 4 1.2.2 PressureSwingAdsorptionMethod ..................... 5 1.2.3 OrganicMembraneSeparationMethod .................. 7 1.2.4 AdsorptionDistillationMethod ........................ 7 1.3 TheUseofCO intheSteelmakingProcess .................... 8 2 1.3.1 UseofCO inaConverter ............................. 8 2 1.3.2 UseofCO inanElectricArcFurnace .................. 9 2 1.3.3 Application of CO in Refining and Continuous 2 Casting ............................................. 10 1.3.4 TheUseofCO intheSmeltingofStainlessSteel ........ 14 2 1.3.5 CO TreatmentofSteelSlag ........................... 16 2 References ..................................................... 16 2 TheThermodynamicsofCO intheSteelmakingProcess .......... 19 2 2.1 ChemicalReactionofCO intheSteelmakingProcess ........... 19 2 2.1.1 CO OxidationatHighTemperature .................... 19 2 2.1.2 EndothermicEffectofCO ............................ 21 2 2.1.3 MechanismofDustReductionbyCO .................. 23 2 2.2 Thermodynamics of Dephosphorization by CO 2 intheSteelmakingProcess ................................... 58 2.2.1 ThermodynamicAnalysisoftheDephosphorization ofMoltenFe ........................................ 58 2.2.2 Effect that the CO Injection Has 2 onDephosphorization ................................ 65 2.2.3 Effect that CO Injection Has on the Selective 2 OxidationofElementsintheMoltenBath ............... 69 2.3 Thermodynamics of CO Used in the Steelmaking 2 andDecarburizationProcesses ............................... 73 ix x Contents 2.3.1 Theoreticalanalysisofthethermodynamics .............. 73 2.3.2 CalculationoftheSurplusHeat ........................ 74 3 TheKineticsofUsingCO inSteelmaking ........................ 77 2 3.1 StudyontheEffectthattheRateoftheUtilizationofCO 2 HasontheSteelmakingProcess .............................. 77 3.1.1 StudyontheRateofUtilizationofCO ................. 77 2 3.1.2 Study on the Utilization Ratios of CO and O 2 2 inaMixedGasInjection .............................. 81 3.2 KineticsofCO DecarburizationinSteelmaking ................ 122 2 3.2.1 KineticsofDecarburizationUsingCO Injection ......... 123 2 3.2.2 DecarburizationKineticsofaMixedCO andO 2 2 Injection ............................................ 158 3.3 KineticsofNRemovalbyCO inSteelmaking ................. 167 2 3.3.1 Controlling the Speed of N Absorption 2 orPrecipitationinMoltenSteel ........................ 167 3.3.2 RateEquationforN AbsorptionorPrecipitation 2 intheMoltenSteel ................................... 171 3.3.3 EffectthattheBottomBlowingofDifferentGases HasontheLiquidSteel[N],[H],and[O]Content ........ 175 4 MaterialsandHeatBalanceoftheCO UsedinSteelmaking ....... 179 2 4.1 The Materials and Heat Balance of the CO Used 2 forthePre-DephosphorizationofMoltenIron(Fe) .............. 179 4.1.1 RawandAuxiliaryMaterialsConditions ................ 180 4.1.2 Assumptions ........................................ 180 4.1.3 MaterialsAnalysisoftheCO UsedintheSteelmaking 2 Process ............................................. 181 4.1.4 ThermalAnalysisoftheCO UsedintheSteelmaking 2 Process ............................................. 186 4.2 CO isUsedintheMaterialsandHeatBalanceofConverter 2 Steelmaking ............................................... 189 4.2.1 RawandAuxiliaryMaterialsConditions ................ 189 4.2.2 Assumptions ........................................ 190 4.2.3 AnalysisoftheCO UsedinSteelmakingMaterials ....... 191 2 4.2.4 ThermalAnalysisoftheCO UsedintheSteelmaking 2 Process ............................................. 194 4.2.5 FinalCalculationoftheMaterialsandHeatBalance ....... 196 4.3 TheMaterialsandHeatBalanceofCO UsedinStainless 2 SteelSmelting ............................................. 199 4.3.1 TheImpactthatCO InjectionHasontheMaterials 2 andEnergyInvolvedinanActualSmeltingProcess inanAODFurnace ................................... 199 4.3.2 The Impact that the CO Injection Ratio Has 2 ontheMaterialsandEnergy ........................... 209 Contents xi 5 BasicTheoryofCO UseinRefining ............................. 215 2 5.1 StudyontheReactionMechanismofBottomBlownCO 2 inanLFFurnace ........................................... 215 5.1.1 ThermodynamicStudyontheReactionofBottom BlownCO inanLFFurnace .......................... 215 2 5.1.2 StudyontheReactionKineticsofBottomBlownCO 2 inanLFFurnace ..................................... 224 5.1.3 Study on the Stirring Mechanism of the Bottom BlowingofCO inanLFFurnace ...................... 231 2 5.2 ApplicationofCO inanAODFurnaceforStainlessSteel 2 Smelting .................................................. 232 5.2.1 ReactionofCO withtheMainElementsintheMolten 2 Steel ............................................... 233 5.2.2 Calculation of the Temperature Rise Associated withCO Oxidation .................................. 234 2 5.2.3 Thermodynamics of Decarburization and [Cr] Retention ........................................... 237 5.2.4 FactSageCalculations ................................ 244 5.2.5 KineticAnalysis ..................................... 250 5.3 Application of CO in an RH Furnace for the Smelting 2 ofLowCSteel ............................................. 261 5.3.1 BasicResearchonCO asanRHLiftingGas ............ 261 2 5.3.2 StudyontheReactionMechanismofCO asanRH 2 LiftingGas .......................................... 268 6 TheTheoryofLimestoneDecomposingCO Steelmaking .......... 283 2 6.1 Silicon (Si) Volatilization in Limestone Slagging andSteelmaking ........................................... 283 6.1.1 MechanismofSiliconVolatilizationintheConverter ...... 283 6.2 Thermodynamic Calculation of Si Volatilization inaLimestoneConverter .................................... 285 6.2.1 InfluencingFactorsofSiVolatilizationintheConverter ... 294 6.2.2 Favorable Conditions for the Volatilization of Si WhenLimestoneisUsedforSlagging .................. 298 6.3 Effect that Oxidation of CO from the Limestone 2 intheConverterHasontheMoltenFe ......................... 300 6.3.1 LimestoneDecompositionReactionExperiments inMoltenFe ........................................ 300 6.3.2 The Thermodynamics of CO and the Selective 2 Oxidationof[C]and[Si] .............................. 313 6.3.3 TheUtilizationRateofCO andMoltenFeReaction ...... 319 2 6.4 The Role of CO in the Dissolution and Decomposition 2 ofLimestone .............................................. 320 6.4.1 ResearchPurpose .................................... 320 6.4.2 ExperimentalMethod ................................. 321