化学沉淀法去除稀土湿法冶炼废水中钙与高浓度氨氮研究王浩

34720137ENVIＲONMENTALSCIENCEVol．34No．7Jul．20131212*11212121.5410042.541004Ca2+Ca2+．Na2CO3CaCO3Ca2+MAP．．SEMXXＲD．nCa2+∶nCO2－3=1∶1.051500r·min－130minCa2+100%pH=9.03nMg∶nN=1.20nP∶nN=1.130min1000r·min－195.40%5.65mg·L－1CaCO3MgNH4PO4·6H2O．XX703.1A0250-3301201307-2718-112012-10-252013-01-061201Z0281987～[e-mail]*[e-mail]h-strengthAmmoniaNitrogenfromtheWastewaterofＲare-earthElementsHydrometallurgicalProcessbyChemicalPrecipitationWANGHao12CHENGGuan-wen12SONGXiao-wei1XUZi-han12MENGJin-jie12DONGChuan-qiang121．CollegeofEnvironmentalScienceandEngineeringGuilinUniversityofTechnologyGuilin541004China2．GuangxiKeyLaboratoryofEnvironmentalPollutionControlTheoryandTechnologyGuilinUniversityofTechnologyGuilin541004ChinaAbstractAlotofhigh-strengthammonianitrogenwastewaterisgeneratedintheion-typerare-earthelementshydrometallurgicalprocess．MagnesiumammoniumphosphateMAPprecipitationwaschosentoremovetheammonianitrogenfromthewastewaterafterCa2+waseliminatedusingNa2CO3togenerateCaCO3precipitatebecausethewastewatercontainedalotofCa2+andCa2+wasanimportantimpactfactorforMAPprecipitation．CentralcompositedesignCCDisaprincipalresponsesurfacemethodologyＲSMusedinexperimentaldesign．ＲesponsesurfacemethodologyＲSMwasusedtooptimizethefactorsinMAPprecipitationachievingtheoptimalconditionsandtheprecipitatesundersuchconditions．TwokindsofprecipitateswereanalyzedbyscanningelectronmicroscopeSEMandX-raydiffractionXＲD．TheresultsshowedthatwhennCa2+∶nCO2－3=1∶1.05mixrateandreactiontimewere1500r·min－1and30minrespectivelytheremovalratioofCa2+reached100%theoptimalconditionofMAPprecipitationwaspH=9.03nMg∶nN=1.20nP∶nN=1.1withareactiontimeof30minandamixrateof1000r·min－1theremovalratioofammonianitrogenreached95.40%andtheresidualtotalphosphorusconcentrationwas5.65mg·L－1．SEMandXＲDanalysisshowedthatthetwokindsofprecipitateswerepureCaCO3andMgNH4PO4·6H2Orespectively．KeywordsmagnesiumammoniumphosphateMAPresponsesurfacemethodologyＲSMCa2+removalrare-earthwastewaterSEMXＲD1MAP2、3、4．MAP．5．267、8、9、10．MAPCa2+MAP11Ca2+．ＲSMDOI:10.13227/j.hjkx.2013.07.045712～14．CaCO3MAPＲSM、、．11.11、、COD、．1.2CaCO3．Na2CO3CaCO3．300mLnCa2+∶nCO2－3Na2CO330min0.45μmCa2+．1Table1Maincompositionsoftheinvestigatedrare-earthwastewaterpHNH+4-N/mg·L－1CODOH-KI/mg·L－1TP/mg·L－1Cl－/mg·L－1Ca2+/mg·L－1Mg2+/mg·L－1Cu/mg·L－1Zn/mg·L－1Fe/mg·L－1Mn/mg·L－1NO－3/mg·L－1CH3COO－/mg·L－1/μS·m－1/NTU2.3844209820314337573529394.865.728.593.23201299534.32×10547.31.3MAPpH、nMg∶nN、nP∶nN、54Na2HPO4·12H2OMgCl2·6H2ONH+4-NTP．．1.4ＲSMcentralcompositedesignCCDＲSM．CCD2k2kn0．pHA、nMg∶nNB、nP∶nNCD4．k=4N=2k+2k+n024+2×4+6=301516NH+4-NY1TPY2．Y=b0+b1A+b2B+b3C+b4D+b12AB+b13AC+b14AD+b23BC+b24BD+b34CD+b11A2+b22B2+b33C2+b44D21Yb0bibiibijA、B、C、D4．Design-Expert8.0.6．1.5．NH+4-NTPCOD．DDSJ-308WGZ-800．DIONEXICS-1000Perkin-ELmerAAnalyst700．MAPJSM-6380LVX'PertPＲOX．22.1Ca2+MAP、、、ρNH+4-N4420mg·L－1、ρCH3COO－9953mg·L－1ρCa2+0、5000、10000、20000、4000080000mg·L－1NH+4-N4.32×105μS·m－1HClpH2.4300mLnMg∶nN∶nP=1∶1∶1MgCl2·6H2ONa2HPO4·12H2O30min30minNH+4-N．1Ca2+NH+4-NCa2+93.52%50%Ca2+MAP．Na2HPO4·12H2OCa2+PO3－4Mg2+NH+4PO3－4NH+4-N．2.2Ca2+MAPNH+4-NMAP9172341Ca2+MAPFig．1EffectofCa2+ontheammonianitrogenremovalbyMAPprecipitationCa2+MAP．．2.2.1Ca2+nCa2+∶nCO2－31∶1、1∶1.01、1∶1.02、1∶1.03、1∶1.04、1∶1.05、1∶1.06、1∶1.07、1∶1.1Na2CO32000r·min－130minCa2+nCa2+∶nCO2－32．Na2CO3Ca2+nCa2+∶nCO2－3=1∶197.47%nCa2+∶nCO2－3=1∶1.0599.9%．CO2－3Ca2+．2nCa2+∶nCO2－3Ca2+Fig．2EffectofnCa2+∶nCO2－3ontheremovalratioofCa2+2.2.2nCa2+∶nCO2－3=1∶1.05、30min3．Ca2+1500r·min－1Ca2+99.9%．CO2－330minCa2+Ca2+．1500r·min－1．2.2.34．20minCa2+99.5%30minCa2+100%．CO2－330minCa2+30min．2.2.4Ca2+nCa2+∶nCO2－3=1∶1.051500r·min－130min．Ca2+99.99%．350℃48hSEMXＲD．55000CaCO36XCaCO3．Na2CO3Ca2+MAP．3Ca2+Fig．3EffectofmixrateontheremovalefficiencyofCa2+2.3MAPMAP．Na2CO3pH027274Ca2+Fig．4EffectofreactiontimeontheremovalefficiencyofCa2+5Fig．5SEMpictureoftheprecipitateformedundertheoptimalconditionsofCa2+removal6XFig．6XＲDpictureoftheprecipitateformedundertheoptimalconditionsofCa2+removalNH+4-NNH+4-N3189.30mg·L－1．2.3.1pH7．pHNH+4-NpH=10NH+4-N89.53%TP36.42mg·L－1Ohlinger17pH=10.3．pHNH+4-NNH+4-N18pH＞10Na2HPO4·12H2OPO3－4Mg3PO42Ksp=1.0×10－24MgNH4PO4Ksp=2.5×10－131920Mg3PO42MgNH4PO421MgNH4PO4．MAPpH9～10．7pHFig．7EffectofpHontheremovalofammonianitrogenandphosphorus2.3.2nMg∶nN8nMg∶nNFig．8EffectofnMg∶nNontheremovalofammonianitrogenandphosphorus8．nP∶nN=1∶1nMg∶nNNH+4-NnMg∶nN=1∶188.98%TPnMg∶nN=1∶140.42mg·L－1nMg∶nN＞1.2∶1TP4mg·L－1．nMg∶nN1∶1Mg2+MAPnMg∶nN＞1∶1Mg2+127234NH+4-NMg2+Mg2+NH+4、PO3－4PO3－4．NH+4-NMg2+nMg∶nN1∶1～1.2∶1．2.3.3nP∶nNnMg∶nN=1∶1nP∶nNNH+4-NTP9．nP∶nN＜1∶1NH+4-NnP∶nNnP∶nNPO3－4NH+4-NNH+4-NPO3－4TPnP∶nN＞1∶1NH+4-N91%TP．PO3－4．nP∶nN0.9∶1～1∶1．9nP∶nNFig．9EffectofnP∶nNontheremovalofammonianitrogenandphosphorus2.3.410．NH+4-N30minTP．20minMAP30min．2.3.511．NH+4-NTPNH+4-N90%～92%TP41～44mg·L－11000～1500r·min－1．MAP．1000～1500r·min－1．10Fig．10Effectofreactiontimeontheremovalofammonianitrogenandphosphorus11Fig．11Effectofmixrateontheremovalofammonianitrogenandphosphorus2.4Design-Expert8.0.6NH+4-NTPNH+4-N3DNH+4-NTP．NH+4-NTPNH+4-NTPNH+4-NTP22．2.4.123．NH+4-