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1、FusedBrownAluminaProductionInChinaTw1Kv7vR6KEugeneP.LunghoferandDr.LarryA.WolfeAugust6,2000ARTICLETOOLSEmailPrintReprintsShareTheabrasiveindustryinChinabeganinthe1940s,whenwhatbecameknownasGrindingWheelFactoryNo.1wasstartedbytheJapanese.Duringthenexttwodecades,theindust
2、ryexpandedwiththeassistanceandtransferoftechnologyfromEastGermany.ThisexpansionwasapartoftheChinesegovernment’sFirstFiveYearProgram.EachnewfactorywasgiventhenameGrindingWheelFactorywithasequentialnumber.Theterm“GrindingWheelFactory”wasall-inclusive,andanyfactorycouldbea
3、ssignedtoproduceoneormoreofthefollowing:rawmaterialsforbondedandcoatedabrasives,bondedabrasives,coatedabrasives,refractoriesandsuperabrasives.GrindingWheelFactoriesNo.1throughNo.7wereestablished,eachwithitsownmissionandareaofspecialization.Inaddition,numerousothersmallm
4、anufacturersofabrasivematerialswereformedthroughoutChina.OneproductstillproducedbyseveraloftheGrindingWheelFactoriestodayisfusedbrownaluminumoxide(BFA),whichistheprimaryabrasivematerialusedintheproductionofgrindingwheelsandcoatedabrasives,aswellasanexcellentrefractoryma
5、terial.BFAisproducedbymeltingandreducingcalcinedbauxiteinanelectricarcfurnace.Thecalcinedbauxitecontainsvaryingamountsofimpurities,suchasironoxide,silicaandtitania,whichmustberemovedduringthemeltingprocess.Theconcentrationoftheimpuritiesisdecreasedtopredeterminedlevelst
6、oensuretheoptimumpropertiesoftheBFAineachintendedapplication.Excessimpuritiesareremovedintheelectricarcfurnacebymeltingthecalcinedbauxitewithadditionsofcarbonandiron.Thecarbonreactswiththeoxygenintheimpuritiestoformcarbonmonoxidegas,andtheimpuritiesarereducedtotheircorr
7、espondingmetals.Themetals,beingdenserandinsolubleinthemoltenBFA,separateandsettletothebottomofthefurnace.Theexcessironcombineswiththesiliconmetaltoformaferrosiliconalloy,whichprecipitatesoutofthemeltandformsapoolatthebottomofthefurnace.BFAProductioninChinaTwodesignsofel
8、ectricarcfurnacesareinoperationinChinatoday:thestationaryorbatchtype,referredtoinNorthAmericaastheHigginsfurna
