ClassifiersClassifiers

Classifiers Kinds

GravitySettling

Settlingtank,Elutriator,Spitzkasten,Doubleconeclassifier,HydraulicJig,Riffledtable

Centrifugalseparators

Hydrocyclonesy y

Electrostaticseparators

FloatationFloatation

( )

GravitySettlingTank

Tank largevolume medium(H2O)lowvelocity Suspensioncontainingparticles introducedintotank veryfinescarriedawaywiththeliquid smallparticles travelfartherfrominletbeforereachingbottom highUt collectnearinlet Ifinsolidformintroduceddownachute,thepositionatwhich

theparticlesaredepositedwillbedeterminedbytherateat

whichtheylosethehorizontalcomponentoftheirvelocities

Surface velocity classifierSurfacevelocityclassifier

Spitzkasten Commercial adaptation of surface velocity classifier CommercialadaptationofsurfacevelocityclassifierWoodenPyramidalboxes/rivetedsteelsheetcones ConicalvesselsarearrangedintheorderofincreasingC/s

area forareafor

Amountofliquidtobehandledincludesallthewaterusedforclassifyinginpreviousvessels

tl b it i d i d t d i t th partlybecauseitisdesiredtoreduceinstagesthesurfacevelocityofthefluidflowingfromonevesselto

next

Coarsestcollectednearfeedpoint,finestattheexitoflastcompartment

Generallyforsizingoperations fordp

FreeSettlingClassifier

separating particles based on their size shape andseparatingparticlesbasedontheirsize,shapeanddensity,usingastreamof gas or liquidflowingina

directionusuallyoppositetothedirectionofy pp

sedimentation

FluidatcontrolledvelocityfedfrombottomSmallerorlighterparticlesrisetothetop(overflow)becausetheirterminalfallingvelocities arelowerthanthe

velocityoftherisingfluid.

SolidswithhigherUt settledownagainsttheupwardcurrent

Relativelysmallersolids(lowerUt)riseupalongwiththecurrent

SeriesofsuchelutriatorswithrelativelylargerC/scanbeusedtoseparatethesolidsintomultiplefractions

Predominatelyusedforparticleswithsize(>1m)

Elutriation or Sizing by Free settlingElutriationorSizingbyFreesettling

Double cone classifierDoubleconeclassifier

Fixedexternalconewithsourceoffluid(hydraulicwater),spigotattip,peripheraloverflowlaunderaroundopenend

Concentricinnertruncatedconesupportedsothattheheightofthisconerelativetooutercone adjustedbyahandwheel

Feedflowsdownwithininnerconeoutoftheopeningagainstabaffle

Hydraulicorotherfluidandfeedmixed@vicinityofbaffleandriseinspacebetweentwoconesAnalysing

column Adjustmentofheightofinnerconeandcontrolofhydraulicwater determinesfluidvelocityinspacebetweencones(i.e.analyzingcolumn)

Capacityofdoubleconeclassifier=1.8A*Y**s A MinimumC/sareaofannularspace(inSq.ft.) Y Volumeconcentration,i.e.,vol.ofsolid/vol.oftotal Velocityintheanalyzingcolumn(fps) s Densityofsolids(lb/cu.Ft.)

GaycoPneumaticClassifier

Drysolidfeedentersthroughhollowshaftfallsuponrotatingfeederplate

Circulatingfancausesairtocirculateupwardandoutwardthroughtheinnercylinder carryingfinesintooutercone

Circulating air returns through slots in the inner cylindricalCirculatingairreturnsthroughslotsintheinnercylindricalsection

Oversizesettlesdownthroughthecirculatingairintobottomofinnerconeseparatelyremoved

Finessettleoutthroughouterconeremovedseparatelyatbottom

For100 400meshparticles

http://sturtevantinc.com/demo/Whirlwind.html

Tabling Shakingtable Panningofgold goldminertoseparatemoredensegoldfromlessdense rock/ganguedenserock/gangue

Separationoftwomaterialsofdifferentdensitiesbypassingdilutepulpoveratable

d kordeck

Inclination 2to5degreesfromhorizontalReciprocating horizontal motion or shake Reciprocatinghorizontalmotionorshake150to37perminute slowforwardmotionandafastreturn causesmaterialtomoveforward

Surfaceoftable coveredwithcanvas,linoleum,cementprovidedwithgroovesorcleatsorformrifflesparalleltodirectionofptablemotionoratanangle

Cleats 0.250.5wideand(1/16)to(1/8) hi h d 0 5 t 2 t(1/8)high,spaced0.5to2apart

Netmovementofparticles resultantoftwoforcesappliedtothem tiltoftableandppvelocityandthicknessofwaterflowingoverit

Tabling

Jigging

Specialformofhinderedsettling Stratificationofparticlesintolayers giving

opportunitytosettleorfallforshortperiodsof

timeandthenremovingthestratifiedlayers

i.e.,separationbasedoninitialfallingvelocitiesofparticles

Whenresistanceforcetofrictioneffectsarenotdevelopedyet,i.e.,dragforce~0

Accelerationofparticlea=(1(/s))g Initial velocity depends on (i) gravity (ii) density Initialvelocitydependson(i)gravity,(ii)density

ofparticleandofthefluid

Independentofsizeandshapeofparticle Thus sorting of two materials based on density ThussortingoftwomaterialsbasedondensityRelativeaccelerationoftwomaterials

aA/aB ={(A )B)/(B )A}

Fixedscreendiaphragmjig

JiggingBasis

Curve1:slateparticleofsameshapeandsizeascoalparticleincurve2

Curve2:largecoalparticleCurve3:mediumslateparticleCurve4:smallestslateparticleCurve5:smallcoalparticle distanceaparticlefallsintimetistheintegralp g

of(vdt)withinlimitsof0tot,i.e.,theareaunder

curve

If the time of sorting or settling allowed to extend Ifthetimeofsortingorsettlingallowedtoextendtot2 areaundercurves2qnd 4arenearly

equalimpossibletoseparatethetwoparticles

equal jigging i e they settle equal distances inequaljigging i.e.,theysettleequaldistancesin

theallowedsettlingperiod

Jigging basedontheinitialvelocityofthefallingparticle

Electrostaticclassification

Basedondifferenceofbehaviourofparticlesinelectricfield

Rolls Pinpointelectrode

(i)Electricchargeonparticle,(ii)differencebetweendielectric

constantsofparticleandsurroundingmedium

Conductiveparticlecomingincontactwithchargedsurfaceorscreen

rollssometimesreplacedbyinclinedchutes

Conductanceseparators

A InitialMaterialBlessconductiveCmoreconductive

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