THE SIZING AND SELECTION OFHYDROCYCLONES

By Richard A. Arterburn

For many years, hydrocyclones,commonly referred to as cyclones, havebeen extensively utilized in the classificationof particles in comminution circuits. Thepractical range of classification for cyclonesis 40 microns to 400 microns, with someremote applications as fine as 5 microns oras coarse as 1000 microns. Cyclones areused in both primary and secondary grindingcircuits as well as regrind circuits. Theinformation given in this paper is intended toprovide a method, at least for estimatingpurposes, of selecting the proper numberand size of cyclones and to determine theproper level of operating variables.Generally, it is recommended that cyclonesuppliers be consulted for sizingconfirmation. Some cyclone suppliersemploy digital computers to aid in the sizingand selection of cyclones.

CYCLONE DESCRIPTION AND BASICOPERATION

Figure 1 shows a cutaway view of atypical cyclone. During operation, the feedslurry enters the cyclone under pressurethrough the feed pipe into the top of thecylindrical feed chamber. This tangentialentrance is accomplished by two types ofdesign, as shown in Figure 2. Since themajority of research has been done with theinvoluted type, the graphs and relationshipsshown may not be strictly applicable to otherdesigns.

As the feed enters the chamber, a rotation ofthe slurry inside of the cyclone begins,causing centrifugal forces to accelerate themovement of the particles towards the outerwall. The particles migrate downward in aspiral pattern through the cylindrical sectionand into the conical section. At this point thesmaller mass particles migrate toward thecenter and spiral upward and out throughthe vortex finder, discharging through theoverflow pipe. This product, which containsthe finer particles and the majority of the

water, is termed the overflow and should bedischarged at or near atmospheric pressure. The higher mass particles remain in adownward spiral path along the walls of theconical section and gradually exit throughthe apex orifice. This product is termed theunderflow and also should be discharged ator near atmospheric pressure.

BASIC PARAMETERS FOR STANDARDCYCLONE

The definition of a “standard cyclone” isthat cyclone which has the propergeometrical relationship between thecyclone diameter, inlet area, vortex finder,apex orifice, and sufficient length providingretention time to properly classify particles.As with the involuted type design, thegraphs and mathematical relationshipsshown for proper selection and sizing ofcyclones apply to the “standard cyclone”geometry. The main parameter is the cyclonediameter. This is the inside diameter of thecylindrical feed chamber. The next parameter is the area of theinlet nozzle at the point of entry into the feedchamber. This is normally a rectangularorifice, with the larger dimension parallel tothe cyclone axis. The basic area of the inletnozzle approximates 0.05 times the cyclonediameter squared. The next important parameter is thevortex finder. The primary function of thevortex finder is to control both the separationand the flow leaving the cyclone. Also, thevortex finder is sufficiently extended belowthe feed entrance to prevent short circuitingof material directly into the overflow. Thesize of the vortex finder equals 0.35 timesthe cyclone diameter. The cylindrical section is the next basicpart of the cyclone and is located betweenthe feed chamber and the conical section. Itis the same diameter as the feed chamberand its function is to lengthen the cycloneand increase the retention time. For thebasic cyclone, its length should be 100% ofthe cyclone diameter. The next section is the conical section,typically referred to as the cone section.The included angle of the cone section isnormally between 10O and 20O and, similarto the cylinder section, provides retentiontime.

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The termination of the cone sectionIs the apex orifice and the critical dimensionis the inside diameter at the discharge point.The size of this orifice is determined by theapplication involved and must be largeenough to permit the solids that have beenclassified to underflow to exit the cyclonewithout plugging. The normal minimumorifice size would be 10% of the cyclonediameter and can be as large as 35%.Below the apex is normally a splash skirt tohelp contain the underflow slurry.

PERFORMANCE

In determining the proper size andnumber of cyclones required for a givenapplication, two main objectives must beconsidered. The first is the classification orseparation that is required, and the secondis the volume of feed slurry to be handled.Before determining whether these objectivescan be achieved, it is necessary to establisha base condition as follows:

1. Feed liquid – water at 20O C.2. Feed solids – spherical particles

of 2.65 sp gr.3. Feed concentration – less than

1% solids by volume4. Pressure drop – 69 kPa (10psi).5. Cyclone geometry – “standard

cyclone” as described above

CLASSIFICATION

Historically, classification has beendefined as the particle size of which 1% to3% reports to the cyclone overflow withcoarser particles reporting to the cycloneunderflow. Recent investigations havedefined classification as the particle size ofwhich 50% reports to the overflow and 50%to the underflow, or the so-called D50C point.Figure 3 shows the typical relationshipbetween particle diameter and the percentrecovered to underflow. The portion of thecurve near the 50% recovery level is quitesteep and lends itself readily to determiningan accurate particle diameter. Examinationof the recovery curve near the 97% to 99%recovery level shows that the curve is nearlyhorizontal and a small differential couldchange the micron diameter considerably.

[Note: The particle size shown on Figure3 and also used for calculations in this paperis defined as the minimum particle diameterof a given size band. For example, aparticle that passes a 150 mesh screen (105microns) but is retained on a 200 meshscreen (74 microns) would actually have adiameter between 74 microns and 105microns. For this paper, the size of 74microns would be used for particles in thissize range.] Figure 3 also shows that the actualrecovery curve does not decrease below acertain level. This indicates that a certainamount of material is always recovered tothe underflow and bypasses classification. Ifa comparison is made between theminimum recovery level of solids to theliquid that is recovered, they are found to beequal. Therefore it is assumed that apercent of all size fractions reports directly tothe underflow as bypassed solids in equalproportion to the liquid split. Then each sizefraction of the actual recovery curve isadjusted by an amount equal to the liquidrecovery to produce the “corrected recovery”curve shown in Figure 3. As the D50C point changes from oneapplication to another, the recovery curvesshift, along the horizontal axis. In order todetermine a single graph which representsthe corrected recovery curve, the particlesize of each size fraction is divided by theD50C value and a “reduced recovery” curvecan be plotted, as shown in Figure 4. Investigations have shown that this curveremains constant over a wide range ofcyclone diameters and operating conditionswhen applied to a slurry containing solids ofa single specific gravity and a typical ornormal size distribution such as thoseencountered in most grinding circuits.Equation 1 gives a mathematicalrelationship which can be used to calculatethe reduced recovery. This recovery, alongwith the bypassed solids, is used to predictthe complete size distribution for theunderflow product.Rr = e4X - 1 (eq. 1) e4X + e4 –2

Where Rr = Recovery to underflow on corrected basis. X = Particle diameter /D50C particle diameter.

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In designing comminution circuits theobjective is to produce an overflow from thecyclone which has a certain size distribution,normally defined as a given percent passinga specified micron size. An empiricalrelationship shown in Table 1 is used torelate the overflow size distribution to theD50C required to produce the specifiedseparation. The relationship of this table isfor typical or average grinding sizedistributions and may vary slightly

depending upon the grinding characteristicsof the ore itself. The separation a cyclone can achievecan be approximated using Equation 2. TheD50C (base) for a given diameter cyclone ismultiplied times a series of correction factorsdesignated by C1, C2, and C3.

(Eq. 2)

D50C(application) = D50C(base)xC1xC2xC3

Table 1. Relationship of D50C to Overflow Size Distribution

Required Overflow Size Distribution Multiplier

(Percent Passing) of (To Be Multiplied Specified Micron Size Times Micron Size)

98.8 0.5495.0 0.7390.0 0.9180.0 1.2570.0 1.6760.0 2.0850.0 2.78

Example: Produce an overflow of 80% passing 149 microns (100 mesh).

Multiplier from Table 1 at 80% passing = 1.25.

Micron size for application = 149 microns (100 mesh).

D50C required = 1.25x149 = 186 microns for application.

This D50C (base) is the micron size that a“standard cyclone” can achieve operatingunder the base conditions and is given inFigure 5 or calculated from Equation 3. Forexample, a 25.4 cm (10 in.) diametercyclone has a base D50C point of 24microns.

D50C(base) = 2.84 x D0.66 (Eq. 3)

Where D = Cyclone diameter in cm.

The first correction (C1) is for theinfluence of the concentration of solidscontained in the feed slurry. The graphicalrepresentation of this correction is shown in

Figure 6 and can be calculated usingEquation 4. Figure 6 indicates that the levelof percent solids is extremely important indetermining the proper separation, as thehigher the concentration the coarser theseparation. It should be pointed out that thiscorrection is a relative measure of slurryviscosity and is affected by such things asthe size of particles present as well asparticle shape. For example, a feed thatcontains a large amount of clay would tendto shift this curve to the left and result in acoarser separation, whereas the absence offines would shift the curve to the right andresult in a finer separation. Many other

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variables such as liquid viscosity also affectthis correction.

-1.43

C1 = 53-V (Eq. 4) 53

Where C1 = Correction for the influence of cyclone feed concentration. V = Percent solids by volume of cyclone feed.

The second correction is for the influenceof pressure drop across the cyclone asmeasured by taking the difference betweenthe feed pressure and the overflowpressure. Pressure drop is a measure ofthe energy being utilized in the cyclone toachieve the separation. It is recommendedthat pressure drops, whenever possible, bedesigned in the 40 to 70 kPa (5 to 10 psi)range to minimize energy requirements aswell as reduce wear rates. This is especiallytrue for coarse separations usuallyassociated with primary or secondarygrinding circuits. The correction for pressure drop isshown in Figure 7 and can be calculatedfrom Equation 5. As indicated, a higherpressure drop would result in a finerseparation and lower pressure drop in acoarser separation.

C2 = 3.27 x �� -0.28 (Eq. 5)

Where C2 = Correction for influence of pressure drop. �� = Pressure drop in kPa.

The next correction is for the effect thatspecific gravity of the solids and liquid haveon the separation. Since the cyclone doesnot actually achieve a size separation butrather a mass separation, the specificgravity of the particle is extremely importantin determining the separation. It isespecially meaningful in applications wherethe mineral has a higher specific gravity thanthe gangue material which allows better

liberation of mineral particles at a coarseroverall separation size. It has been found that Stoke’s law can beapplied to determine particle diameterswhich would produce the same terminalsettling velocity for a particle of knownspecific gravity in a liquid of known specificgravity as compared to a particle of 2.65specific gravity in water. This relationship isshown in Figure 8 and can be calculatedusing Equation 6.

0.5C3 = 1.65 GS - GL (Eq. 6)

Where C3 = Correction for influence of specific gravity GS = Specific gravity of solids GL = Specific gravity of liquid (normally 1.0)

The cyclone diameter, along with the threecorrections of percent solids, pressure drop,and specific gravity, are the main variablesnecessary for preliminary sizing andselection of cyclones. Other variables, suchas the vortex finder and inlet size, also havean effect on separation. For example, alarger vortex finder size would tend tocoarsen the separation, whereas a smallersize would tend to achieve a finerseparation. Due to this fact, most cycloneshave a replaceable vortex finder withdifferent sizes available. Vortex finderdiameters vary from a minimum of about25% of the cyclone diameter to a maximumof about 45%. The inlet area also shows thesame effect as the vortex finder, but not aspronounced. The apex size also has an effect onseparation but the effect is minor unless theapex is too small and becomes a physicalconstraint, forcing material into the overflow. Cyclone retention time is also a minorfactor influencing cyclone performance.Within limits, increased retention time wouldhelp achieve a finer separation; whereasreduced retention time would coarsen theseparation. The retention time of thecyclone can be altered by either changingthe length of the cylindrical section or bychanging the cone angle.

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There are numerous other variableswhich also have an effect of separation;however, these variables are relatively minorand may be neglected for the preliminarysizing and selection of cyclones.

FLOW RATE

The second main objective which must beconsidered is to provide adequate cyclonecapacity for the application. The volume offeed slurry that a given cyclone can handleis related to the pressure drop across thecyclone. The relationship between flow rateand pressure drop for several different sizesof standard cyclones is shown in Figure 9.As shown, the flow rate increases as thepressure drop increases. In order to utilizethis graph, the pressure drop used forcalculating the separation is used todetermine the flow rate for the cyclonediameter which was also used fordetermining the separation. The flow rate isthen divided into the total flow for a specificapplication to determine the number of unitsnecessary. Since the flow rate given in Figure 9 is forwater rather than slurry, it should bementioned that slurry normally increases thecapacity of a cyclone over that shown forwater; however, for preliminary estimatesthis factor can be neglected. This will resultin the number of cyclones calculated beingslightly higher than those actually needed.Approximately 20% to 25% standbycyclones are recommended for operationalas well as maintenance flexibility. The vortex finder size and inlet area of acyclone also have an effect on thevolumetric flow rate that a given cyclone canhandle. Larger vortex finders or inlet areaswould increase the capacity, whereassmaller vortex finders or inlet areas woulddecrease the capacity. The shaded area inFigure 9 corresponding to each standardcyclone gives the approximate range ofcapacity for each cyclone.

APEX SELECTION

The proper selection of apex size iscritical to proper cyclone performance. Foreach application a circulating load isnormally given which establishes theamount of solids which must pass throughthe cyclone underflow. Experience has

shown that an underflow density of 50% to53% solids by volume is typical for primarygrinding circuits, whereas an underflowdensity of 40% to 45% solids by volume isnormal for regrind circuits. Therefore, anunderflow density can be assumed whichestablishes the total flow rate that mustreport through each cyclone apex. Figure10 shows the approximate flow rate for agiven diameter apex orifice.

OPERATIONAL AND DESIGNCONSIDERATIONS

One of the most important considerationsis to insure that cyclones are installedproperly. A detailed list of “Do’s and Don’ts”is given in a later chapter.

FEED PIPING AND DISTRIBUTION

A most important consideration for agiven cyclone system is proper delivery ofthe slurry to the cyclone or cyclones. It hasbeen found that a pipe size which producesa line velocity of 200 to 300cm/sec (7 to 10ft/sec) is high enough to prevent particlesfrom settling, even in horizontal sections, butlow enough to minimize wear. Normally fora single cyclone installation the inlet pipesize of the manufacturer’s recommendationproduces a velocity in this area. If the slurry is to be distributed to anumber of cyclones operating in parallel,extreme care should be given to the designof the distribution system, and a radial typeof manifold is recommended. This is asystem where the cyclones are fed from acentral circular chamber. When properlydesigned the central chamber becomes amixing area and the line velocity should belowered to approximately 60 to 90 cm/sec (2to 3 ft/sec). This will help insure that eachcyclone is fed with the same slurryconcentration as well as the same particlesize distribution and also will reduce wearrates. Using the radial manifold also makesit easier to install standby cyclones. Should an inline type manifold be utilized,the cyclones do not receive gooddistribution. It is typical that the high massparticles or coarser particles tend to passthe first cyclones and report to the finalcyclone. This results in the last cyclonereceiving a higher feed concentration ofcoarser particles, which accelerates the

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wear of the last cyclone as well as producesa coarser separation due to the higher feeddensity. Also, the last cyclone, once shutoff, becomes difficult to restart because thesolids will tend to pack into the feed pipe. For applications where the separation isnot critical or one in which the feedconcentration is extremely low, an inlinemanifold is acceptable and is much lessexpensive than the radial type.

MATERIALS OF CONSTRUCTION

Cyclone Construction varies greatly fromone manufacturer to another, but themajority of the designs includes metalhousings with replaceable liners withreplaceable liners with the most suitableliner material varying from one application toanother. It is also common to utilize severaldifferent lining materials within the samecyclone to optimize wear characteristics. Natural gum rubber is the most commonmaterial utilized due to its relatively low cost,excellent wear, ease of handling, and it isnot fragile. Applications where gum rubberis not suitable are those where thetemperatures exceed 60OC or there arelarge amounts of hydrocarbons present inthe slurry such as oil or other detrimentalchemicals. Ceramic materials have foundacceptance as cyclone liners for the apexorifice as well as other areas which exhibitsevere abrasion. These include areas suchas the lower cone liner and vortex finder. Nihard has also proven to be anacceptable wear material, especially forvortex finders and other areas which requirestrength as well as abrasion resistance. Other elastomer materials such asneoprene and nitrite are also utilized whenhydrocarbons are present or when thetemperature exceeds 60OC. Urethane hasfound acceptance, especially in areas wherethe solids are relatively fine.

PRESSURE DROP CALCULATIONS

As mentioned earlier, the pressure dropacross a cyclone is measured by taking thedifference between the feed pressure andthe overflow pressure. If the overflow isdischarged at near atmospheric pressure as

recommended, the feed pressure is thesame as the pressure drop. Cyclone selection provides the pressuredrop required, and for pump calculations thismust be converted to meters of slurry whichcan then be added to the static and frictionheads to determine the total dynamic headfor the pump. Equation 7 is used forconversion of pressure drop to meters ofslurry.

M = �� x 0.102 (Eq. 7) G

Where M = Meters, slurry. �� = Pressure drop, kPa. G = Sp gr of slurry.

As stated, it is recommended that boththe overflow and underflow products bedischarged at atmospheric pressure.Should the overflow be discharged against apositive head, some of the fluid whichnormally reports to the overflow is forced toreport to the underflow. This does not havea major effect on classification but doesincrease the amount of bypass solids andreduces underflow density. Should the overflow be discharged at apoint lower than the feed entrance, apossible siphon can be established whichwould cause a breakdown in classificationand could bring larger particles into theoverflow. A large siphon effect couldactually dislodge a worn liner which in turnwould plug the overflow piping. Siphons canbe prevented by installing a vent pipe on theoverflow piping of each cyclone. The underflow should also be dischargedat or near atmospheric pressure. Should theunderflow be discharged at a negativepressure, the effect would be similar to apositive pressure at the cyclone overflow. Ifthe underflow is discharged against apositive pressure, the amount of flow isreduced and a larger apex must be selectedin order to insure that the classified solidscan discharge freely.

SUMP/PUMP DESIGN

Another chapter covers the selection andsizing of slurry pumps and should beconsulted for more detailed informationconcerning sump/pump design. Specifically

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regarding cyclone applications, the feedslurry being delivered to a cyclone should beas steady as possible with regard to bothvolumetric flow rate and slurry density.Unsteady feed conditions such as severepump surging or extreme variations in slurrydensity are very detrimental to good cycloneperformance. In general, a sump/pumpsystem for a cyclone application shouldhave a sump with as much depth aspossible and a minimum cross-sectionalarea consistent with the pumpmanufacturer’s recommended retentiontime. A sump of this design will normallyeliminate pump surging by allowing smallvariations in sump level well above theminimum pump suction level. The smallcross-sectional area will reduce the buildupof solids in the bottom of the sump and helpprevent large sections of the settled solids toslough into the pump suction and plug eitherthe cyclone feed line or the cyclone apex.Therefore, a tall sump with a small cross-sectional area provides much smootheroperation.

APEX DISCHARGE PATTERN

An Important part of cyclone operation isbeing able to observe the type of patternthat the cyclone apex is producing. An apexoperating at atmospheric pressure shouldproduce a cone shaped discharge with anangle of 20O to 30O and a hollow center. Ifthe cyclone consistently produces a highangle cone spray, the apex orifice should bereduced in size to maximize the slurrydensity being discharged. On the otherhand, should the cone spray be void of thehollow center and resemble a “rope”, thenthe apex is too small and oversize materialmay be reporting to the cyclone overflow. Inthis case, a larger apex orifice should beinstalled.

EXAMPLE PROBLEM

Example – Primary Grinding Circuit

Problem: Select the proper size andnumber of cyclones for a rod mill/ball millcircuit where new feed to the rod mill is 250metric tons per hour (MTPH) solids. Bothmill discharges join together at cyclone feedsump and are pumped to cyclones.Overflow is to be 60% - 200 mesh (74

microns) at a minimum of 40% solids byweight. Underflow becomes ball mill feed.Specific gravity of solids is 2.9 andestimated circulating load is 225%.

STEP 1. Calculate material balance fromknown information. Overflow must be 250MTPH at 40% solids.

Overflow:

MTPH solids = 250MTPH water = 375MTPH slurry = 625% solids, wt = 40Sp gr slurry = 1.3551/sec slurry = 128 (2030 USGPM) (1/sec = liters per second)

Underflow: (based on 2.25 x overflow):

MTPH solids = 562MTPH water = 187MTPH slurry = 749% solids, wt = 75 (assumed atSp gr slurry = 1.9661/sec slurry = 106 (1676 USGPM)

Feed (sum of overflow and underflow):

MTPH solids = 812MTPH liquid = 562MTPH slurry = 1374% solids, wt = 59.1Sp gr slurry = 1.6321/sec slurry = 234 (3706 USGPM)% solids, vol. = 33.2 (necessary for separation calculations)

STEP 2. Calculate required D50C forspecified overflow of 60% passing 74microns.

From Table 1:

Multiplier at 60% passing = 2.08Specified micron size = 74 micronsD50C (application) = 2.08x74 = 154 microns

STEP 3. Calculate cyclone diameterrequired.

First, calculate C1, C2 and C3:

C1 = Correction for feed density = 4.09

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(from Figure 6)C2 = Correction for �� = 1.1 (from Figure 7). Pressure drop assumed at 50 kPa (7 psi) which would be low energy and good maintenance.C3 = Correction for sp gr solids = 0.93 (from Figure 8)

Second, calculate cyclone diameter:

D50C (application) = D50C (base) x C1xC2xc3 (from Equation 2)154 = D50C (base) x 4.09xl.lx0.93D50C (base) = 37 microns

Therefore, from Figure 5 use 51 cmcyclones (20 in.).

STEP 4. Calculate number of unitsrequired.

From Figure 9:

Flow rate for 51 cm cyclone at 50 kPa = 40 1/secTotal feed flow = 234 1/sec

Therefore, number of units = 234/40 = 5.85 or use 6 cyclones in operation.

STEP 5. Calculate proper apex size.

Total underflow = 106 1/secUnderflow per unit = 106/6 = 18 1/secFrom Figure 10 each apex should be 9.5 cm (3 ¾ in.)

CONCLUSION

It has been the intent of this paper to providea method for determining the proper sizeand number of cyclones required for thedesign of a comminution circuit. The partsof a cyclone and the geometry whichcomprise a standard cylone were described.Cyclone performance, as well as thefundamental variables of cyclone diameter,feed concentration, pressure drop, andspecific gravities, has been explained. Bothgraphical representations and mathematicalrelationships have been given for each ofthe fundamental variables, and cyclone andapex capacities have been presented.

Other design and installation informationsuch as feed distribution systems, materialsof construction, pressure drop calculations,sump/pump design, and apex pattern werediscussed. An example problem for aprimary rod mill/ball mill grinding circuit wasalso given. Although the method for determining theproper size and selection of hydrocyclonesin this paper has proven to be quiteaccurate, the engineer should still be awareof the fact that variations in orecharacteristics have an effect on cycloneperformance. In cases where the slurrycharacteristics are questionable, pilot plantinformation should be used to provide moreaccurate cyclone sizing and selection.

BIBLIOGRAPHY

Arterburn, R.A., 1976, “The Sizing ofHydrocyclones, Krebs Engineers, MenloPark, CA.

Bradley, D. 1965, The Hydrocyclone,Pergamon Press, Oxford.

Gaudin, A.M., 1939, Principles of MineralDressing, McGraw Hill, New York andLondon.

Lynch, A.J. and Rao, T.C., 1968, “TheOperatint Characteristics of HydrocycloneClassifiers, “Ind. J. of Tech., 6.

Lynch, A.J., Rao, T.C. and Prisbrey, 1974,“Influence of Hydrocyclone Diameter onReduced Efficiency Curves,” InternationalJournal of Mineral Processing, 1, 173.

Mular, A.L. and Bull, W.R. (Editors), 1969,“Mineral Processes: Their Analysis,Optimization and Control,” QueensUniversity, Ontario.

Mular, A. L. and Jull, N.A., 1978, TheSelection of Cyclone Classifiers, Pumps andPump Boxes for Grinding Circuits, MineralProcessing Plant Design, AIME, New York.

Plitt, L.R., 1976, “A Mathematical Model ofthe Hydrocyclone Classifier,” CIM Bull. 69,114.

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Tarr, D.T., 1965, “Practical Application ofLiquid Cyclones in Mineral DressingProblems,” AIME Fall Meeting.

Wills, B.A., 1981, Mineral ProcessingTechnology, 2nd Ed., Pergamon Press,Oxford.

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FIGURE 1CYCLONE CUTAWAY

Cylindrical Feed Chamber

Cylinder Section

Conical Section

Apex

Vortex Finder

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Figure IIInvoluted Feed vs. Tangential Feed

Involuted Feed

Tangential feed

12

0

10

20

30

40

50

60

70

80

90

100

20 30 40 50 60 70 80 90 100 200 300 400 500

Graph IPar t ic le Diam eter VS. Par t ic le Recovery

Par t ic le Diam eter (Mic rons)

Pa

r tic

le R

eco v

e ry

(% t

o U

nder

flow

)

Ac t ua lRecovery

Correc tedRecovery

D50 Point

Figure 3. Particle Recovery Curves

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Particle Diameter (microns) /D50 (microns)0.2

10

20

30

40

50

60

70

80

90

100

0

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.5 2 2.5 3 3.5 4 4.5 5

Graph IIReduced Recovery

Parti

cle

Rec

over

y (%

to u

nder

flow

)

Figure 4. Reduced Particle Recovery Curve

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3

4

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6

7

8

9

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25

3 0

35

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1 2 3 4 5 6 7 8 9 10 15 20 25 30 40 50 60

Gr a p h I I ICyc lon e Dia m e t e r VS. D50

(For "Typ ic a l " Cyc lon es )

D50

(M

icro

n s)

Cyc lon e Dia m e t e r (In c h es )

Figure 5. Cyclone Diameter versus D50c for Standard Cyclone

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Gra ph IVCor r ec t ion For Feed Con c en t r a t ion

Cor

rect

ion

Fact

or

Feed Con c en t r a t i on (% so l i d s b y vo lu m e)0 5 10 15 20 25 30 35 40 45 50

0

2

3

4

5

6789

10

15

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30

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60708090

100

Figure 6. Influence of Feed Concentration on Separation

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0 .4

0 .45

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0 .65

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0 .75

0 .8

0 .85

0 .9

0 .95

1

1 .5

2

2 .5

3

Cor

rect

ion

Fa

ctor

Gr a p h VCor r e c t i on Fo r Pr e s su r e Dr op

Pr e s s u r e Dr op (PSI )

3 4 5 6 7 8 9 10 15 20 2 5 30 40 50 60

7 0 80 90 100

Figure 7. Influence of Pressure Drop on Separation

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0.4

0 .5

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1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5

10

Cor

r ect

ion

Fa

ctor

Gr a p h VICor rec t ion fo r So l id s Sp ec i f i c Gra vi t y

( in w a t e r )

So l id s Sp ec i f i c Gr a vi t y

Figure 8. Influence of Solids Specific Gravity on Separation

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15

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8090

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1,000

5,000

9,0003 4 5 6 7 8 9 10 15 20 25 30 40 50 60 70 80 90 10

0

Graph VIIPressure Drop VS. Volum et r ic Flow rat e

Vol

um

etri

c Fl

o wra

te (

US

GP

M)

Pressure Drop (PSI)

30" Cyc lone

26" Cyc lone

20" Cyc lone

15" Cyc lone

10" Cyc lone

6" Cyc lone

4" Cyc lone

Figure 9. Water Capacity for Standard Cyclone

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1

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5060

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10,000

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3 4 5 6 7 8 9 10

Graph VIIIApex Capacity

Diameter VS. Flowrate

Flow

Ra

te (

GP

M)

Apex DiaMeter (inches)

Figure 10. Apex Capacity Curve