红土镍矿酸浸渣硫酸铵焙烧-超声分散-离心分离提纯增白效果与机理

红土镍矿酸浸渣作为提镍废渣,存量大、白度低、重金属含量高。 为实现它在相关领域的 回收应用及高值开发,本文通过研究红土镍矿酸浸渣原矿、提纯增白样品和尾渣的化学成分、物 相、微观形貌、孔结构以及焙烧过程中的气相,并通过同步热分析与红外-质谱(TG-FTIR-MS)联 用系统,以及XRD、SEM、EDS等手段对提纯增白机理进行了分析。 提纯增白机理为:预先煅烧去 除有机杂质并将铁、铝、铬等离子氧化,二段焙烧将金属氧化物通过一系列反应转化为NH4(Al、 Fe、Cr)(SO4)2,并在超声波作用下溶于水中经洗涤去除,未参与反应的六方硫镍矿和砷化锗镉还 有部分石英经离心沉淀去除。 试验结果:红土镍矿酸浸渣白度由56% 提升到84% 、含铁量由 0.92% 下降到0.2% 、比表面积由84m2/g提升到96m2/g、回收率达到47% 以上。

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.Thesecond-stageroastingconvertsmetaloxidesintoNH4(Al、Fe、Cr)(SO4)2throughaseriesofreactions, thenleachingdissolvedinwaterundertheactionofultrasoundandremovedbywashing.Theheazlewooditeandcadmiumgermaniumarsenideandsomequartzwhichhadnotparticipatedinreactionswere removedbycentrifugalprecipitation.Thewhitenessofacid-leachingresidueoflateritenickelwasincreasedfrom56% to84%,theironcontentdecreasedfrom0.92% to0.2%,thespecificsurfacearea israisedfrom84m2/gto96m2/g,andtherecoveryratereachesmorethan47%.