简介:大约90?没有全面利用,%稀土元素矿物质和许多另外的珍贵矿物质作为铁跟踪是heaped。为了包括地恢复这些珍贵矿物质,在Baotou钢跟踪和嵌入的特征的珍贵矿石类型的一个看法,珍贵部件流动和他们在beneficiation程序表联合关系的各自的恢复被分析;能把考虑给四种部件的进程流动和参数是坚定的。TFe,稀土元素氧化物(REO),铌和荧石恢复能到达72.70%,81.84%,78.58%并且60.18?在low-intensity/high-intensity的%磁性的分离分别地。高紧张的磁性的集中被REO直接筹款对待;恢复是75.43?%,在Fe能与Nb完全被分开的底上。underflow被减小roasting-low-intensity对待磁性的分离。并且在这些珍贵部件的恢复之间的关系也被讨论。
简介:InBaotourareearthtailingsore,thegradeofrareearthisclosetothatoftheraworenearly.Therareearthsarediscardedintailingsdamcausedbyaseriouswasteofresources.Firstofall,thedecompositionproductsofbastnaesite-andmonazite-mixedrareearthtailingsinCaOinreducingatmospherewerestudiedbymeansofX-raydiffraction(XRD).TheresultsshowthatthenormalproductsareCeO_2,Ce_2O_3,Ca_5F(PO_4)_3,andCe_(0.75)Nd_(0.25)O_(1.875),andtherearenoREPO_4andREFCO_3.Secondly,theroastedproductwasextractedinHCl,andtherelationshipamongroastingtime,roastingtemperature,CaOaddition,andextractiontemperaturewasstudiedbythequadraticregression-orthogonalanalysis.Throughanalysis,theoptimumprocessconditionsofmixedrareearthtailingsextractedareobtainedasfollows:roastingtimeof60min,roastingtemperatureof800℃,CaOadditionof30%,extractiontemperatureof80℃,andextractionratioof99.18%.
简介:ThestructureofPb,Zn,CuandCdinleadzincoretailingsoilsinYongzhou,HunanisanalyzedbytheoptimizedBCRsequentialextractionprocedure.Thecontentandproportionofheavymetalsoftheminearemeasured.Meanwhile,theecologicalrisksareevaluatedwiththeLarsHakanson’spotentialecologicalriskexponentialmethod.Theanalysisshowsthatthecontentofheavymetalsisveryhigh,reachingthelevelofseriouspollution.TheorderofmetalpollutiondegreesareCd>Pb>Cu>Zn.Ontheotherhand,itisverypossiblethattheheavymetalsmaycombinetogetherascompoundsorclingtothecrystalformofclay.Sincetheformofsolubleacidandfreemetalsareverylittle,itisnotaneasyjobformetalelutingorrestorationofplants.Yetitispossibletotakeoutthoseheavymetalsadoptingthechemicalextractiontechnology.DTPAandEDTA,indicatedbyaresearch,bothhaveiterativevalueandstrongconformityeffect.Sotheyareeffectiveelutriantstorestorethepollutedsoil.Achemicalextractionmethodisputforwardinthispaper.
简介:Theobjectiveofthisstudywastoinvestigatetheef-fectsofearthwormdensityontheavailabilityofnutrientsandheavymetalsinmetalcontaminatedsoils.Pb/Znminetailingsweremixedthroughlywitharedyellowpodzolicsoilattheratio(w/w)of75:25.Earthworms(Pheretimasp.)wereintroducedtothemixtureatfourdifferentdensities,zero,three,sixandnineindividualsperpotplantedwithryegrass(Loliunmultiflorum).Theresultsindicatedthatearthwormactivitysignificantlyen-hancedryegrassshootbiomass.However,asdenserearthwormpopulationwasintroduced,shootbiomasstendedtodecrease.EarthwormactivitysignificantlyincreasedsoilpHandavailabilityofN,PandKinthetailingsandsoilmixture.TherewasageneraltendencythatuptakeofZnbyryegrassincreasedafterearthworminoculation,althoughtheincreaseinextractableZnintailingsandsoilmixturewasnotsignificant.Onthecontrary,thereseemedtobealoweruptakeofPbbyryegrassunderearthworminoclation,despitethefactthathigherextractablePbconcentrationswereobserved.Thepresentprojectindicatedthattheimprovedgrowthofryegrasswasduetoimprovednutrientavailabilityandothersoilconditions,byinoculationofearthwormsatanappropriaterate.Furtherstudiesareneededtoillustratetherelationshipbe-tweenmetalavailabilityandearthwormactivityinthefield.
简介:Carbonofhumusacids(HSAC)anddissolvedorganiccarbon(DOC)arethemostactiveformsofsoilorganiccarbon(SOC)andplayanimportantroleinglobalcarbonrecycling.WeinvestigatedtheconcentrationsofHSAC,water-solubleorganiccarbon(WSOC),hotwater-extractableorganiccarbon(HWOC)andSOCinsoilsunderdifferentvegetationtypesoffourcopperminetailingssiteswithdifferingvegetationsuccessiontimeperiodsinTongling,China.TheconcentrationsofHSAC,WSOC,HWOCandSOCincreasedwithvegetationsuccession.WSOCconcentrationincreasedwiththeaccumulationofSOCinthetailings,andalinearlypositivecorrelationexistedbetweentheconcentrationsofHSACandSOCinthetailings.However,thepercentagesofHSACandDOCintheSOCdecreasedduringvegetationsuccession.TherateofSOCaccumulationwashigherwhenthesuccessiontimewaslongerthan20years,whereasthespeedsofsoilorganicmatter(SOM)decompositionandhumificationwereslow,andtheconcentrationsofHSACandDOCincreasedslowlyinthetailings.Thepercentageofcarbonofhumicacid(HAC)inHSACincreasedwithvegetationsuccession,andthevaluesofhumificationindex(HI),HAC/carbonoffulvicacid,alsoincreasedwiththeaccumulationofHSACandSOCinsoilsofthetailingssites.However,theHIvalueintheeachofthetailingswaslessthan0.50.ThehumificationrateofSOMwaslowerthantheaccumulationrateofSOM,andthelevelofsoilfertilitywasstillverylowinthetailingsevenafter40yearsofnaturalrestoration.