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..Unit1Lesson11矿物〔mineralsMineralsdefinition:Mineralsbydefinitionarenaturalinorganicsubstancespossessingdefinitechemicalcompositionsandatomicstructures.矿物的定义:具有稳定的化学成分、晶体结构的天然无机化合物。Mineraltypes:nativeandmetallicform,oxides,sulphides,carbonates,silicatesandchlorides.矿物的种类:主要按化学成分划分:单质矿物、氧化物、硫化物、碳酸盐、硅酸盐、卤化物等。Isomorphism:substitutionofatomswithinthecrystalstructurebysimilaratomstakesplacewithoutaffectingtheatomicstructure.类质同象:矿物晶体中的原子被类似原子取代而不改变矿物晶体结构的现象。例如:铁橄榄石—镁橄榄石。Polymorphism:differentmineralshavethesamechemicalcomposition,butmarkedlydifferentphysicalpropertiesduetoadifferenceinatomicstructure.同质多象:矿物的化学成分相同,但晶体结构和物理化学性质不同的现象。例如:金刚石、石墨。Rocks:Rocksconsistofavarietyofmineralsandformlargepartsoftheearth’scrust.Granite,forinstance,whichisthemostabundantigneousrock,iscomposedofthreemainmineralconstituents,feldspar,quartz,andmica.岩石:由一种或多种矿物组成的天然集合体,例如:花岗岩主要由石英、长石、云母以不同比例组成。2矿石oresOre:Anorecanbedescribedbrieflyasanaccumulationofmineralinsufficientquantityastobecapableofeconomicextraction.矿石:具有经济利用价值的矿物集合体.Classification:〔1Oresarefrequentlyclassedaccordingtothenatureofthevaluablemineral,suchasnativeores,sulphideoresandoxidisedores.〔2Oresarealsoclassifiedbythenatureoftheirgangues,suchascalcareousorbasic<limerich>,orsiliceous,oracidic<silicarich>矿石的分类:〔1根据有用矿物的性质分为:自然元素矿石<单质矿石>、硫化矿和氧化矿等。〔2根据脉石矿物的性质分为:钙质矿石、硅质矿石、酸性矿石等。3金属矿石与非金属矿石metallicoresandnon-metallicoresOresofeconomicvaluecanbeclassedasmetallic<whenitisusedtopreparethemetal>ornon-metallic<whenitisusedtomakematerial>,accordingtotheuseofthemineral.根据矿物的用途划分:如果以提取矿物中的金属为目的,则成为金属矿石;如果矿物直接利用,则称之为非金属矿石。Reviewofthelastlesson1矿物〔mineralsMineralsbydefinitionarenaturalinorganicsubstancespossessingdefinitechemicalcompositionsandatomicstructures.Isomorphism:Manymineralsexhibitisomorphism,wheresubstitutionofatomswithinthecrystalstructurebysimilaratomstakesplacewithoutaffectingtheatomicstructure.Polymorphism:Mineralscanalsoexhibitpolymorphism,differentmineralshavingthesamechemicalcomposition,butmarkedlydifferentphysicalpropertiesduetoadifferenceinatomicstructure.2矿石oresOre:Anorecanbedescribedbrieflyasanaccumulationofmineralinsufficientquantityastobecapableofeconomicextraction.3金属矿石与非金属矿石metallicoresandnon-metallicoresOresofeconomicvaluecanbeclassedasmetallic<whenitisusedtopreparethemetal>ornon-metallic<whenitisusedtomakematerial>,accordingtotheuseofthemineral.Lesson2Typesofcoal煤的种类Lignite,Sub-bituminouscoal,BituminouscoalandAnthracite.主要包括:褐煤、亚烟煤、烟煤、无烟煤Cokinganduseofcoke炼焦及焦炭的应用Cokeisasolidcarbonaceousresiduederivedfromlow-ash,low-sulfurbituminouscoalfromwhichthevolatileconstituentsaredrivenoffbybakinginanovenwithoutoxygenattemperaturesashighas1,000°C<1,832°F>sothatthefixedcarbonandresidualasharefusedtogether.焦炭是一种从低灰、低硫的烟煤中获得的固态碳质残余物,烟煤在隔绝氧气的条件下和1000度的高温下焙烧,驱除其中的挥发份,使固定碳和残留灰分熔融在一起。GasificationCoalgasificationbreaksdownthecoalintoitscomponents,usuallybysubjectingittohightemperatureandpressure,usingsteamandmeasuredamountsofoxygen.煤气化是将煤分解为不同的组分,通常是使用蒸汽和一定量的氧气气氛,在高温、高压条件下进行。Liquefaction液化包括间接液化和直接液化两种方法Indirectsynthesis:CoalwouldbegasifiedtomakesyngasandthesyngascanbecondensedusingFischer-Tropschcatalysts<催化剂>tomakelighthydrocarbonswhicharefurtherprocessedintogasolineanddiesel.间接液化:首先将煤气化为合成气,然后在催化剂作用下将合成气浓缩制备轻质烃油,轻质烃油在进一步转化为汽油和柴油。Directliquefactionprocesses:liquefactionbyhydrogenation,SolventRefinedCoal,Karrickprocess直接液化:包括加氢液化、溶剂精炼、Karrick法等。TheFischer-Tropschprocess<orFischer-TropschSynthesis>isacatalyzedchemicalreactioninwhichsynthesisgas<syngas>,amixtureofcarbonmonoxideandhydrogen,isconvertedintoliquidhydrocarbonsofvariousforms.Themostcommoncatalystsarebasedonironandcobalt,althoughnickelandrutheniumhavealsobeenused.Theprincipalpurposeofthisprocessistoproduceasyntheticpetroleumsubstitute,typicallyfromcoal,naturalgasorbiomass,foruseassyntheticlubricationoilorassyntheticfuel.Sasol<SouthAfricanCoalandOil>isaSouthAfricancompanyinvolvedinmining,energy,chemicalsandsynfuels.Inparticular,theyproducepetrolanddieselprofitablyfromcoalandnaturalgasusingFischer-Tropschsynthesis.TheBergiusProcessisamethodofproductionofliquidhydrocarbonsforuseassyntheticfuelbyhydrogenationoflignite<browncoal>athightemperatureandpressure.ItwasfirstdevelopedbyFriedrichBergiusin1913.Ligniteorsub-bituminouscoalisfinelygroundandmixedwithheavyoilrecycledfromtheprocess.Catalystistypicallyaddedtothemixture.Anumberofcatalystshavebeendevelopedovertheyears,includingtungstenormolybdenumsulfides,tinornickeloleate,andothers.Naphthanormallyreferstoanumberofdifferentflammableliquidmixturesofhydrocarbons,i.e.adistillationproductfrompetroleumorcoaltarboilinginacertainrangeandcontainingcertainhydrocarbons,abroadtermencompassinganyvolatile,flammableliquidhydrocarbonmixture.TheKarrickprocessisalow-temperaturecarbonization<LTC>ofcoal,shale,ligniteoranycarbonaceousmaterials.Theseareheatedat680
°F<360
°C>to1380°F<360°Cto749°C>intheabsenceofairtodistilloutoilandgas.TheprocesswastheworkofoilshaletechnologistattheU.S.BureauofMinesinthe1920s.Chinahasannouncedhighvolumecommercialcoalliquefactionproductioninlate2007[1],afterasuccessfultrial,startingaprocessthatcouldrapidlyfreeChinafromdependencyuponexternalOPECoilimports.Theprocessisreportedtohave'60-meter-highcylindricalstructures'andtobeadirectcoalliquefactionprocess.Whilelackingformalconfirmation,theprocessdescribedseemsidenticaltotheKarrickprocess.ReviewofthelastlessonTypesofcoal煤的种类Lignite,Sub-bituminouscoal,BituminouscoalandAnthracite.Cokinganduseofcoke炼焦及焦炭的应用Cokeisasolidcarbonaceousresiduederivedfromlow-ash,low-sulfurbituminouscoalfromwhichthevolatileconstituentsaredrivenoffbybakinginanovenwithoutoxygenattemperaturesashighas1,000°Csothatthefixedcarbonandresidualasharefusedtogether.Gasification汽化Coalgasificationbreaksdownthecoalintoitscomponents,usuallybysubjectingittohightemperatureandpressure,usingsteamandmeasuredamountsofoxygen.Liquefaction液化Indirectsynthesis:CoalwouldbegasifiedtomakesyngasandthesyngascanbecondensedusingFischer-Tropschcatalyststomakelighthydrocarbonswhicharefurtherprocessedintogasolineanddiesel.Directliquefactionprocesses:liquefactionbyhydrogenation,SolventRefinedCoal,KarrickprocessTheFischer-Tropschprocessisacatalyzedchemicalreactioninwhichsynthesisgas,isconvertedintoliquidhydrocarbonsofvariousforms.TheKarrickprocessisalow-temperaturecarbonization<LTC>ofcoal,shale,ligniteoranycarbonaceousmaterials.Theseareheatedat360°Cto749°Cintheabsenceofairtodistilloutoilandgas.Lesson3IntroductionCoalassaytechniquesarespecificanalyticalmethodsdesignedtomeasuretheparticularphysicalandchemicalpropertiesofcoals煤质分析技术是指用于分析煤的物理和化学性质的特定分析方法。Chemicalpropertiesofcoal煤的化学性能Eachtypeofcoalhasacertainsetofphysicalparameterswhicharemostlycontrolledbymoisture,volatilecontent<intermsofaliphaticoraromatichydrocarbons>,ashcontentandcarboncontent.每一种煤都有一系列物理性能参数,主要包括水分、挥发份〔包括脂肪烃和芳香烃、灰分和含碳量。ChemicalAnalysis化学分析Coalisalsoassayedforoxygencontent,hydrogencontentandsulphur.Sulphurisalsoanalysedtodeterminewhetheritisasulfidemineralorinasulfateform。煤的化学分析主要包括氧、氢、硫含量的分析。对硫来说,还要确定是硫化物还是硫酸盐。PhysicalandMechanicalProperties物理和机械性能Relativedensity,Particlesizedistribution,Float-sinkTest,AbrasionTesting相对密度、颗粒粒度分布、浮沉试验、磨耗试验/耐磨试验SpecialCombustionTests特殊燃烧试验SpecificEnergy,AshFusionTest,SwellingIndextest比能、灰熔性试验,膨胀性试验ReviewofthelastlessonChemicalpropertiesofcoalEachtypeofcoalhasacertainsetofphysicalparameterswhicharemostlycontrolledbymoisture,volatilecontent<intermsofaliphaticoraromatichydrocarbons>,ashcontentandcarboncontent.ChemicalAnalysisCoalisalsoassayedforoxygencontent,hydrogencontentandsulphur.Sulphurisalsoanalysedtodeterminewhetheritisasulfidemineralorinasulfateform。PhysicalandMechanicalPropertiesRelativedensity,Particlesizedistribution,Float-sinkTest,AbrasionTestingSpecialCombustionTestsSpecificEnergy,AshFusionTest,SwellingIndextestLesson41ConceptofmineralprocessingItisaprocessofphysicallyseparatingthegrainsofvaluablemineralsfromthegangueminerals.矿物加工是从脉石矿物中分离有用矿物的过程。2FunctionofmineralprocessingInthemajorityofcasestheenergyconsumedindirectsmeltingorleachingoflowgradeoreswouldbesoenormousastomakethecostprohibitive〔昂贵的、禁止的.在大多是情况下,低品位矿石直接熔炼或浸出的能耗巨大、成本昂贵。Mineralprocessingreducesthebulkandweightofmaterialwhichmustbetransportedtothesmelter,thelackofundesirablewastematerialsincreasesthesmelterrecovery.矿物加工能够使送往冶炼厂的原料体积和重量大大减少,而且,因原料中的杂质含量低,有利于提高冶炼回收率。2MainoperationsTherearetwofundamentaloperationsinmineralprocessing,namelytheliberationofthevaluablemineralsfromtheirwastegangueminerals,andseparationofthesevaluesfromthegangue.矿物加工有两类基本的作业,称为有用矿物从脉石矿物中的解离和有用矿物与脉石矿物的分离〔富集。Liberation:Liberationofthevaluablemineralsfromthegangueisaccomplishedbycomminutiontosuchaparticlesizethattheproductisamixtureofrelativelycleanparticlesofmineralandgangue.解离:有用矿物与脉石矿物的解离是由粉碎来完成的,粉碎粒度要保证产品成为较为纯净的有用矿物和脉石矿物颗粒的混合物。Concentration:Separationisusuallyachievedbyutilizingsomespecificdifferenceinphysicalorchemicalpropertiesbetweenthevaluablemineralandganguemineralsintheore.富集:分离通常利用矿石中有用矿物和脉石矿物物理或化学性质的差异来完成的。Mineralprocessingmethods1.Separationdependentonopticalandradioactiveproperties根据矿物光学性质或放射性的差异。2.Separationdependentonspecificgravitydifferences.根据矿物比重的的差异3.Separationutilizingthedifferentsurfacepropertiesoftheminerals.根据矿物表面性质的的差异。4.Separationdependentonmagneticproperties根据矿物磁性的差异。5.Separationdependentonelectricalconductivityproperties.根据矿物导电性的差异。OtherimportantstepsHeattreatment:Roasting,Calcination,sizingoftheoreanddewateringofthemineralpulps.热处理:焙烧,煅烧,矿石的分级和矿浆脱水。Reviewofthelastlesson1ConceptofmineralprocessingItisaprocessofphysicallyseparatingthegrainsofvaluablemineralsfromthegangueminerals.2FunctionofmineralprocessingInthemajorityofcasestheenergyconsumedindirectsmeltingorleachingoflowgradeoreswouldbesoenormousastomakethecostprohibitive。Mineralprocessingreducesthebulkandweightofmaterialwhichmustbetransportedtothesmelter,thelackofundesirablewastematerialsincreasesthesmelterrecovery.3MainoperationsTherearetwofundamentaloperationsinmineralprocessing,namelytheliberationofthevaluablemineralsfromtheirwastegangueminerals,andseparationofthesevaluesfromthegangue.4Mineralprocessingmethods1.Separationdependentonopticalandradioactiveproperties2.Separationdependentonspecificgravitydifferences.3.Separationutilizingthedifferentsurfacepropertiesoftheminerals.4.Separationdependentonmagneticproperties5.Separationdependentonelectricalconductivityproperties.Lesson5LockedParticles连生颗粒/连生体Theparticlescontainingmineralalsocontainsaportionofgangue.既含有有用矿物,又含有脉石矿物的颗粒,称为连生颗粒.Degreeofliberation解离度The"degreeofliberation"referstothepercentageofthemineraloccurringasfreeparticlesintheoreinrelationtothetotalcontent.解离度,是指矿石中以纯矿物颗粒形式存在的矿物含量占该矿物在矿石中总含量的百分比.Optimummeshofgrind最佳磨矿粒度Inpractice,oresaregroundtoanoptimummeshofgrind,determinedbylaboratoryandpilotscaletestwork,toproduceaneconomicdegreeofliberation.实践中,通过实验室实验和半工业实验,确定一个最佳磨矿粒度,使矿石达到一个经济的解离度.Twostageseparation两段分选/阶段分选Thismethoddiscardsmostofthecoarsegangueearlyintheprocess,thusconsiderablyreducinggrindingcosts,asneedlesscomminutionofliberatedgangueisavoided.采用阶段分选,可以在及早地丢弃粗颗粒脉石,这样就避免了已解离脉石的不必要粉碎,能够大大降低磨矿成本.ReviewofthelastlessonLockedParticlesTheparticlescontainingmineralalsocontainsaportionofgangue.DegreeofliberationThe"degreeofliberation"referstothepercentageofthemineraloccurringasfreeparticlesintheoreinrelationtothetotalcontent.OptimummeshofgrindInpractice,oresaregroundtoanoptimummeshofgrind,determinedbylaboratoryandpilotscaletestwork,toproduceaneconomicdegreeofliberation.TwostageseparationThismethoddiscardsmostofthecoarsegangueearlyintheprocess,thusconsiderablyreducinggrindingcosts,asneedlesscomminutionofliberatedgangueisavoided.Lesson61Theobjectofmineralprocessing矿物加工的目的Theobjectofmineralprocessing,regardlessofthemethodused,isalwaysthesame,i.e.toseparatethemineralsintotwoormoreproductswiththevaluesintheconcentrates,thegangueinthetailings,andthe"locked"particlesinthemiddlings.无论采用什么方法,矿物加工的目的都是一样的,就是把矿物分离为两种或两种以上的产品,使有用矿物进入精矿、脉石矿物进入尾矿、连生颗粒进入中矿。2LimitationofMineralProcessing矿物加工的局限性Suchseparationsare,ofcourse,neverperfect,sothatmuchofthemiddlingsproducedare,infact,misplaced<混杂的>particles.Thisisoftenparticularlyseriouswhentreatingultra-fineparticles,wheretheefficiencyofseparationisusuallylow.矿物分选不是完美的,大部分中矿实际上是混杂颗粒。尤其是处理超细颗粒时,这种情况更为严重,分选效率也比较低。3Recovery回收率Therecovery,inthecaseoftheconcentrationofametallicore,isthepercentageofthetotalmetalcontainedintheorethatisrecoveredintheconcentrate.对于金属矿选矿来讲,回收率是指进入精矿中金属占矿石中金属总量的百分比。4Theratioofconcentration选矿比Theratioofconcentrationistheratiooftheweightofthefeedtotheweightoftheconcentrates.选矿比是指给矿〔原矿重量与精矿重量之比。〔表示生产1吨精矿所需要处理的原矿数量5Grade品位Thegrade,orassay,usuallyreferstothecontentofthemarketableendproductinthematerial.品位通常指物料中所含适销最终产品的含量〔如金属含量,铁矿石中TFe的含量。6EnrichmentratioTheenrichmentratio〔富集比istheratioofthegradeoftheconcentratetothegradeoftheheads,andagainisrelatedtotheefficiencyoftheprocess.ReviewofthelastlessonTheobjectofmineralprocessingTheobjectofmineralprocessing,regardlessofthemethodused,isalwaysthesame,i.e.toseparatethemineralsintotwoormoreproductswiththevaluesintheconcentrates,thegangueinthetailings,andthe"locked"particlesinthemiddlings.RecoveryTherecovery,inthecaseoftheconcentrationofametallicore,isthepercentageofthetotalmetalcontainedintheorethatisrecoveredintheconcentrate.4TheratioofconcentrationTheratioofconcentrationistheratiooftheweightofthefeedtotheweightoftheconcentrates.GradeThegrade,orassay,usuallyreferstothecontentofthemarketableendproductinthematerial.EnrichmentratioTheenrichmentratioistheratioofthegradeoftheconcentratetothegradeoftheheads,andagainisrelatedtotheefficiencyoftheprocess.Unit2Lesson1Introduction简介Theliberationofvaluablemineralsfromtheganguemineralsisachievedbycomminution,inwhichtheparticlesizeoftheoreisprogressivelyreduceduntilthecleanparticlesofmineralcanbeseparatedbysomeconcentratingmethods.有用矿物与脉石矿物的解离是通过粉碎完成的,通过粉碎使矿石颗粒逐步减小至能够分离的纯净颗粒。CrushingandGrinding破碎与磨矿Crushingisaccomplishedbycompressionoftheoreagainstrigidsurface,orbyimpactthesurfacesinarigidlyconstrainedmotionpath.破碎是靠刚性表面对矿石的压力或是在严格限定的运动轨道内,表面对矿石的冲击而实现的。Grindingisaccomplishedbyabrasionandimpactoftheorebythefreemotionofunconnectedmediasuchasrods,balls,orpebbles.磨矿是矿石被钢棒、钢球或砾石等离散介质的研磨和冲击作用而完成的。Strainofacrystallattice晶格的变形Inthecrystallinelatticeofminerals,theinter-atomicbondsareeffectiveonlyoversmalldistances,andcanbebrokenifextendedbyatensilestress.在矿物晶格中,原子间的键力仅在一个很小的距离内有效,能够被拉应力拉伸而断裂。Stressconcentration应力集中Thedistributionofstressdependsuponthemechanicalpropertiesoftheindividualminerals,butmoreimportantly,uponthepresenceofcracksorflawsinthematrix,whichactassitesforstressconcentration.应力分布取决于各种不同矿物的力学性质,但更重要地取决于矿石内部中裂隙和裂纹的存在,因为这些地方能够成为应力集中的部位。Crackpropagation裂纹扩展Materialsfailbycrackpropagationwhentheenergyreleasedbyrelaxingthestrainenergyisgreaterthantheenergyofthenewsurfaceproduced.当释放的形变能大于新生表面能时,材料就能够通过裂纹扩展而破裂。Modesoffracture破裂模式Breakageisachievedmainlybycrushing,impact,andattrition.Therfore,therearethreemodesoffracturesuchascompressive,tensile,andshearfracture.〔矿石破裂主要通过压碎、冲击和研磨作用而实现。因此,主要有压力破裂、拉力破裂和剪切破裂三种破裂模式。ReviewofthelastlessonFunctionofcomminutionTheliberationofvaluablemineralsfromtheganguemineralsisachievedbycomminution,inwhichtheparticlesizeoftheoreisprogressivelyreduceduntilthecleanparticlesofmineralcanbeseparatedbysomeconcentratingmethods.CrushingandGrindingCrushingisaccomplishedbycompressionoftheoreagainstrigidsurface,orbyimpactthesurfacesinarigidlyconstrainedmotionpath.Grindingisaccomplishedbyabrasionandimpactoftheorebythefreemotionofunconnectedmediasuchasrods,balls,orpebbles.StrainofacrystallatticeInthecrystallinelatticeofminerals,theinter-atomicbondsareeffectiveonlyoversmalldistances,andcanbebrokenifextendedbyatensilestress.StressconcentrationThedistributionofstressdependsuponthemechanicalpropertiesoftheindividualminerals,butmoreimportantly,uponthepresenceofcracksorflawsinthematrix,whichactassitesforstressconcentration.CrackpropagationMaterialsfailbycrackpropagationwhentheenergyreleasedbyrelaxingthestrainenergyisgreaterthantheenergyofthenewsurfaceproduced.ModesoffractureBreakageisachievedmainlybycrushing,impact,andattrition.Therfore,therearethreemodesoffracturesuchascompressive,tensile,andshearfracture.Lesson3PrimaryCrushers<粗碎破碎机>破碎在选矿中的作用:破碎属于矿石准备阶段,是矿物加工过程的重要环节,主要目的在于为后续磨矿或分选作业准备适宜的矿石粒度。破碎机种类:按照作业性质分为粗碎、中碎和细碎三种;按照设备型式分为:颚式破碎机、旋回式破碎机、圆锥破碎机、辊式破碎机、冲击式破碎机等。粗碎破碎机:主要包括颚式破碎机和旋回破碎机两大类.颚式破碎机:破碎腔由固定颚板和运动颚板组成,通过动颚向对于定颚的摆动,使矿石受到挤压、破碎。根据动颚的运动特性,又分为简单摆动式和复杂摆动式两种。通常作为粗碎设备使用,不能挤满给矿。旋回破碎机:破碎腔由固定锥〔倒立截头圆锥和固定锥中间的运动锥〔正立截头圆锥组成,通过动锥向对于定锥的摆动,使矿石受到挤压、破碎。通常作为粗碎设备使用,其特点是允许挤满给矿、处理能力大。颚式破碎机结构示意图颚式破碎机原理示意图简单摆动式〔双肘板复杂摆动式〔单肘板旋回破碎机结构及原理PrimarycrushersPrimarycrushersareheavy-dutymachines,usedtoreducetherun-of-mineoredowntoasizesuitablefortransportandforfeedingthesecondarycrushers.Therearetwomaintypesofprimarycrusherinmetalliferousoperations--jaw〔颚式andgyratory〔旋回.JawCrushersThedistinctivefeatureofthisclassofcrusheristhetwoplateswhichopenandshutlikeanimaljaws.GyratoryCrushers〔旋回破碎机Thegyratorycrusherconsistsessentiallyofalongspindle〔轴,carryingahardsteelconicalgrindingelement〔研磨体,seatedinaneccentricsleeve〔轴套.Atanycross-sectionofthecrushingchamberthereareineffect〔实际上、有效twosetsofjawsopeningandshuttinglikejawcrushers.ReviewofthelastlessonPrimarycrushersPrimarycrushersareheavy-dutymachines,usedtoreducetherun-of-mineoredowntoasizesuitablefortransportandforfeedingthesecondarycrushers.Therearetwomaintypesofprimarycrusherinmetalliferousoperations--jawandgyratory.JawCrushersThedistinctivefeatureofthisclassofcrusheristhetwoplateswhichopenandshutlikeanimaljaws.GyratoryCrushersThegyratorycrusherconsistsessentiallyofalongspindle,carryingahardsteelconicalgrindingelement,seatedinaneccentricsleeve.Atanycross-sectionofthecrushingchamberthereareineffecttwosetsofjawsopeningandshuttinglikejawcrushers.Lesson4SecondaryCrushers圆锥破碎机:结构与旋回破碎机相似,所不同的是,破碎腔由两个相互平行的正立截头圆锥组成,固定锥和运动锥表面有一段平行面,排矿粒度较细,通常作为中细碎设备使用。圆锥破碎机:按照破碎腔的型式又可分为:标准型〔给矿口大,平行区短、短头型〔给矿口小,平行区长、中间型则〔给矿口、平行区居中。辊式破碎机:破碎腔由两个相向转动的辊子组成,矿石在两辊之间受到挤压、破碎。可作为选煤厂破碎设备或中小型金属矿选矿厂细碎设备使用,其特点是能量利用率高、适用于脆性和粘性矿石,但处理能力较小,在大型金属矿中应用较少。冲击式粉碎机〔锤式破碎机可分为锤式破碎机和反击式破碎机。冲击式破碎机中有一高速旋转的转子,上面装有冲击锤。当物料进入破碎机后,被高速旋转的锤子击碎或从高速旋转的转子获得能量,被高速抛向破碎机壁或特设的硬板而被击碎。该机的优点是结构简单,设备紧凑,处理能力大,破碎比大,功率消耗小,维护、修理和更换易损件容易,产品粒度较均匀,过粉碎少。缺点是锤头、篦条、衬板和转子圆盘磨损较快,特别是破碎较硬物料时磨损更快,当破碎物料的水分含量超过12%或含有粘土时,它的篦条缝隙容易堵塞,从而降低生产率,且增加能量消耗和锤头等零件的磨耗。滚筒破碎机〔碎煤机:该机为穿孔圆筒,内部设有倾斜提升板,转动过程中将煤块提升至顶部后抛落,靠煤块自身重量冲击破碎。破碎后的细颗粒从孔板中排出。ReviewofthelastlessonSecondaryCrushersTheconecrusherisamodifiedgyratory.Theessentialdifferenceisthattheshorterspindleoftheconecrusherisnotsuspended,asinthegyratory,butissupportedinacurved,universalbearingbelowthegyratoryheadorcone.Themodeofoperationofrollcrushersisextremelysimple,thestandardspringrollsconsistingoftwohorizontalcylinderswhichrevolvetowardseachother.Inimpactcrushers,comminutionisbyimpactratherthancompression,bysharpblowsappliedathighspeedtofree-fallingrock.Therotarycoalbreakerisverysimilarinoperationtothecylindricaltrommelscreen,consistingofacylinderof1.8-3.6mindiameterandlengthofabout1.5to2.5timesthediameter,revolvingataspeedofabout12-18revmin-1.Lesson5Grindingmills根据磨机筒体内装入介质类型的不同,分为:a.球磨机:装入的研磨介质是钢球或铁球。b.棒磨机;筒体内装入的研磨介质是钢棒。c.砾磨机:装入的介质是砾石。d.自磨机:靠矿石中大块自磨。根据磨机筒体的形状,分为:a.短筒型磨机,其长〔L径〔D比小于等于1-1.5。b.长筒型磨机,其长〔L径〔D比大于等于1.5-2;当二者比值更大时,例如5~6时则叫做管磨机。c.圆锥型磨机。选厂采用得最多的磨机是球磨机、捧磨机。自磨机和砾磨机的应用也日益增多。球磨机的结构和原理筒体中空轴颈及轴承大齿轮及驱动机构磨矿介质:钢球自磨机筒体直径〔D大,长度〔L短,一般D/L=3。2中空轴颈的直径大,长度短,直径大是为了适应给矿块度大的需要,通常中空轴颈内径为最大给矿块度的两倍左右,长度短使给矿畅通。ReviewofthelastlessonGrindingisthelaststageintheprocessofcomminution,anditisperformedinrotatingcylindricalsteelvesselsknownastumblingmills<滚筒磨机>.Tumblingmillsareofthreebasictypes:rod,ballandautogenous〔自生的mills.rodmill:Thedistinctivefeatureofarodmillisthatthelengthofthecylindricalshellisbetween1.5and2.5timesitsdiameter.Thetermballmillisrestrictedtothosehavingalengthtodiameterratioof1.5to1andless.Ballmillsinwhichthelengthtodiameterratioisbetween3and5aredesignatedtubemills.Theautogenousmillusestumblingtoeffectcomminution,butinsteadofutilizingmediasuchassteelrodsorballs,comminutionisachievedbytheactionoftheoreparticlesoneachother.Semi-autogenousmillingreferstogrindingmethodsusingacombinationoftheoreandareducedloadofsteelrodsorballsasthemedium.Unit3Lesson1TypesofScreens1.筛分的概念筛分就是将颗粒大小不同的混合物料,通过单层或多层筛于分成若干个不同粒度级别的过程。矿物在经过破碎后,常常以各种粒度不同的物料混合存在,有的物料甚至还含有水分、粘土或其他杂质,所以需通过筛分以满足生产工艺及操作过程的要求。筛分机械分类筛分机械的分类方法较多,可按运动轨迹、传动方式分类,也可按其用途分类。通常分为固定筛和运动筛两大类.常用筛分机械的种类见表3.3。TypesofscreensStationaryScreensThegrizzly.initssimplestform,consistsofaseriesofheavyparallelbarssetinaframe.Sievebends.hasacurvedscreencomposedofhorizontalwedge〔楔形bars.Revolvingscreenisaslightlyinclined,rotatingcylindricalscreen,whichcanbeusedwetordry.MovingScreensShakingscreens.Theyarewidelyuseddryincoalpreparation,butfindlittleuseonabrasivemetalliferousores.Reciprocatingscreen.Reciprocatingscreensemployahorizontalgyratorymotiontothefeedendofarectangularscreenbymeansofanunbalancedrotatingshaft.Gyratoryscreens.Thistypeofscreen,whichimpartsgyratorymotionthroughoutthewholescreencloth,isbecomingwidelyusedforfinescreeningapplications.Vibratingscreens.Theirmainapplicationisincrushingcircuitswheretheyarerequiredtohandlematerialranging,ingeneral,from25cmto5mminsize.Lesson2PrinciplesofClassification--FreeSettling1.分级概念粒度、形状和比重不同的矿粒群,在水中按沉降速度的不同分成若干窄级别的作业,称为湿式分级。在闭路磨矿流程中,分级设备的作用在于及时分出磨矿合格产物,避免过磨。同时又可以分出不合格的粗砂,返回再磨。这对于保证较好的分选效果及提高磨矿效率意义很大。自由沉降:沉降过程中,单个物体在无限的介质中的沉降,称为自由沉降。介质阻力:介质阻力由摩擦阻力<粘滞阻力>和压差阻力〔紊流阻力所组成,这两种阻力同时作用在矿粒上。摩擦阻力:由于介质的粘性,使介质分子与矿粒表面存在粘性摩擦力,这种因粘性摩擦力所致的阻力,称为摩擦阻力。压差阻力:由于介质的惯性,使运动矿粒前后介质的流动状态和动压力不同,这种因压力差所引起的阻力,称为压差阻力。等降比:沉降过程中,往往存在某些粒度大、密度小的矿粒同粒度小、密度大的矿粒以相同沉降速度沉降的观象。叫做等降现象。密度和粒度不同但具有相同沉降速度的矿粒,称为等降颗粒。等降颗粒中,小密度矿粒的粒度与大密度矿粒的粒度之比,称为等降比。ReviewofthelastlessonPrinciplesofclassificationClassificationisamethodofseparatingmixturesofmineralsintotwoormoreproductsonthebasisofthevelocitywithwhichthegrainsfallthroughafluidmedium.Freesettlingreferstothesinkingofparticlesinavolumeoffluidwhichislargewithrespecttothetotalvolumeofparticle,henceparticlecrowdingisnegligible.Resistancetosettlingparticles:Inaviscousmedium,resistancetothesettlingparticlesmovementincreaseswithvelocity.Factorsaffectingtheterminalvelocity:theterminalvelocityofaparticleinaparticularfluidisafunctiononlyoftheparticlesizeanddensity.Free-settlingratioistheratioofparticlesizerequiredforthetwomineralstofallatequalrates.Lesson4TypesofClassifier1.分级机种类。传统分为两类:按照流体流动方向分为垂直流分级机和水平流分级机。垂直流动分级机主要为水力分级机;水平流分级机主要包括:沉降锥和机械分级机。2.常用设备:上述分类方法并不科学,因为有些设备并不符合上述分类方法。在磨矿回路中常用的分级机主要包括机械分级机和水力旋流器两种;在重选中常用的分级机包括沉降锥和水力分级机两种。<1>水力分级机主要用于重选给矿的分级,目的是将混合粒级分为不同的窄粒度级别,便于重选处理。四室水力分级机:力度大小不同的颗粒分别在不同分级箱中沉积。〔2沉降锥〔脱泥斗粗粒沉降速度快,从底部排出,细泥难沉降从顶部溢流堰排出,达到脱泥和浓缩的目的。〔3机械分级机-螺旋分级机矿浆从分级机的给矿口给入倾斜安装的U形槽体。随着螺旋的低速回转和连续不断地搅拌矿浆,使得大部分轻而细的颗粒悬浮于上面,从溢流堰溢出,成为溢流产品;粗而重的颗粒将沉降于槽底,成为沉砂,由螺旋输送到分级机的返砂排矿口排出。v〔4水力旋流器是一种利用离心力作用的分级设备。构造简单,没有运动部件,体积很小,占地面积少,单位面积处理能力大,操作维护方便,成本较低。目前,我国一些选矿厂已经成功地用水力旋流器代替了螺旋分级机。此外,还可用于浓缩、脱泥、选煤等领域。它存在砂泵动力消耗大,设备磨损严重,以及给矿压力、给矿量波动对生产指标有影响等缺点。ReviewofthelastlessonTypesofclassifiersHydraulicclassifiers<verticalcurrentclassifiers>normallyconsistofseriesofsortingcolumnsthrougheachofwhichaverticalcurrentofwaterisrisingandparticlesaresettlingout.HorizontalCurrentClassifiersincludeSettlingconesandMechanicalclassifiers.Settlingconesareoftenusedinthe
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