Study on the process and mechanism of acid-leaching residue of laterite nickel roasting whitening and ultrasonic-assisted centrifugal purification

Asnickelextractionresidue,theacid-leachingresidueoflateritenickelhasalargestock,low whitenessandhighheavymetalcontent.Inordertorealizeitsrecyclingapplicationandhighvaluedevelopmentinrelatedfields,inthispaper,thechemicalconstituents,phase,microscopicmorphology,pore structureandgasphaseintheroastingprocessoftherawacid-leachingresidueoflateritenickel,purifiedandwhitenedsamplesandtailingswerestudied.Themechanismofpurificationandwhiteningwas analyzedbymeansofsimultaneousthermogravimetryanalyzerandinfraredspectroscopy-massspectrometer(TG-FTIR-MS),aswellasXRD,SEMandEDS.Themechanismofpurifyingandwhiteningisprecalcinationto remove organic impurities and oxidation of iron,aluminum and chromium ions.The
second-stageroastingconvertsmetaloxidesintoNH4(Al、Fe、Cr)(SO4)2throughaseriesofreactions, thenleachingdissolvedinwaterundertheactionofultrasoundandremovedbywashing.Theheazlewooditeandcadmiumgermaniumarsenideandsomequartzwhichhadnotparticipatedinreactionswere removedbycentrifugalprecipitation.Thewhitenessofacid-leachingresidueoflateritenickelwasincreasedfrom56% to84%,theironcontentdecreasedfrom0.92% to0.2%,thespecificsurfacearea israisedfrom84m2/gto96m2/g,andtherecoveryratereachesmorethan47%.