MIneral Processing Design and Operations

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M

Processing

and p

An Introduction

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CONTENTS

CHAPTER 1. MINERAL SAMPLING

I. n-mtODUCTlON \

l.l. STATISTICAL TERMINOLOGY \

1.2. MINERAL PARTlCLliS DU'FERlNG IN SIZE- GY'S METHOD 7

1.3. MINERAL PARTICLES OF DIFfERENT DENSITY II

I.~. INCRE.'lEl'oTAL SAMPLII'G 13

U. OOm1NUOUS SAMPLING OF STREA.\lS 20

1.6. SAMPLING ORES Ot· PRECIOUS METALS 24

1.7. SAMI'I.INO NOMOQRAPHS 25

1.8. PROBU'.M.S 28

REFEREKCES 31

CHAPTER 2 PARTICLE SIZEESTlMATION AND DlSJlUBUllOSS

2. n-mtODUcnO~ )2

2.1. METHODS OF SIZ£ ESTIMATlO~

n

2.2. PARTICLE SIZE DlSllUBUTION 45

2.3. COMSINING S17J! DlSTRlSUT10NS 53

2-4. PROBLEMS 59

REFEIlID'CES 62

CHAPTER 3. SIZE REDUCTION AND !!NERGY REQUlREMIlNT

3. NrRODUCTION 63

3.1. DESIGN Of SIZE REDUCTION PROCESSES 63

l.2. EI'o'ERGY FOR SIZE REDUCTIO:'; • WORK INDEX 65 3.1. ESTIMATION OF WORK INDEX I'OR CRUSHERS

AND GRINDING MILLS lit

3.4. PROBU'.M.S 92

REfERENCES 'YI

CHAPTER 4. JAW CRUSHER

4. NrRODUCTIOS

4.1. DESIGN Of JAW CRUSHERS

42. JAWCRUSI1EROPERATlON

4.3. JAWCRUSHERCAPACJTY

4.4. CRJTICAL OPERA TIND SPEED

4.5. POWER CONSUMPTION

4.6. PROBLEMS

REt'ERE/<iCES

CHAPTER 5. GYRATORY AND CONE CRUSHER

S. lNTlI.ODUCTION

S.1. DESIG~OFGYRATORYCRUSHERS

S.2. GYRATORY CRUSHER CIRCUIT DESIGN

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B. GYRATORY CRUSHER Dr[RATION ~.4, CAPACITY

5.5. POWEll. CONSU:vJI'TION ~.6, PROBUiMS

REfERENCES

CHAPTER 6. ROLL CRUSHERS

6. IN1RODUCnON

6.1. DESIGN OF ROll CRUSHERS

6.2. OPERA nON OF ROLL CRUSHERS 6.3. OJ'AC/TY OF ROLL CRUSHERS

6.4. POWER CONSUMPTION OF ROLL CRUSHERS

6.S. HIGH PRFSSURE GRINDING ROLLS (HPGR)

M . OPJORA'llQ:>I O~ ItI'(jR 6,7. CAPACITYOfHPQR

6.1. POWER CONSUMPTION Of HPGR

M . PROI;lLEMS REFERENCES

CHAPTER 7. nmUlAR BAll. MILts

7. u.,.IRODUCTION

7.1, DESIGN OF TIlBUlAR MILLS

7.2. OPERA nON OF TIJBULAR IIALL MILLS

7.3. ESTIMATION OF MILL CAPACITY

7.4. MILL POWER DRAW-MEClIA)<IlCALMETIIODS 7.S. PROBLEMS

REFERENCES

CHAPTI:.R I. TIJBlJU.R ROD MlLl.S B. INIlI.ODUCTION

1.1. DESIGN OF ROD MILLS 8.2. OPEI!.A TlON

m

'

ROD MILLS B.), ROD MILLCAPJl.C!TY

U. ROD MILL POWER DRAIT

8.5. MILL DRIVE 8.6. PROBl.F.MS REFERENCES

CHA I"ffiR 9. AlITOGENOUS AND SKI.f!·AlITOOFNOUS MIU.~

9. INTRODUCTION

9.1. DESIGN OF AG/SAG MILLS

9.2. OPERATION OF AG/SAO MILLS

9.). AG/SAG MIl l POW£;.R

9..4. CHOICE OF omONS BETWEEN AO A,,"O SAG MILLS

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CHAmR 10. )'lAltIEMAllCAL MOOOUJNG 1:-: COMMI~unON

10. INTRODUCTION 255

10.1, BASIS FOR MODELLING COMMl)'.'UTlON S YS'I'EMS 256

10.2. MAlllEMATrCAL MODEI-S or CO~IMlNlITION PROCESSrs 26)

10.3. MODELLNGCkUSlliNOANDGlUNDINGSYSTEMS 268

10.4, PROBLEMS 288

REFERENCES 291

CIiAI'TER 11. SCREENING

11. INil!ODCCTION

11.1. RASle DESIGN FEATURES IN SCREENS

11.2 OPERATION OF STRAIGHT SCREENS

11.3. CAl'AClry ANIl SCREEN SELECIION U~'

STRAIGHT SCREENS

11.4. OPERATION OF CURVED SCREENS

11.5. MODELUNG OFTHESCREEl\"NG PROCESS

11.6. SCREENfl'.:G AND CRUSlliNG CIRCUITS

1 U . PROBLEJ.1S REFERD:CE-~ ClIAPHR 12. CLASSIFICATION

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12. lNll!.ODUCTION l~

12.1. OESIGN fL\ TIJRES OF ).tECI1AN1CAL CLASSIFIERS 3~4

12.2. OF-S1GNING 'fIlE POOL AREA OF MECHANICAL

CLASSIFIERS 359

12-3. DI;..~I(]r<: FEATURES OF CEl'-'TRIFUGAL CLASSIFIERS ]<,5

12.4. OPERATION OF MECIIANICAL CL\SSIl'I~RS 369

12.~. CAPACITY OF MECIlM'ICAl. CLASSIFll,RS 377

12.6. OPERATION OF CENTRIFUGAL CLASSIFIERS 378

12.1.IIYIJROCYCWNE MODELS 386 12.8. IlYDROCYCtQNECAPAClTY 388 12.9. IIYDROCYCtQt->E CIRClJlTS 392 12.10. PROBLEMS 39~ REFERENCES 399 CHArrER

n.

SOLJD-Ll()U1D~EPARATION 13. IN"il!.ODUCTION

0.1. Df~IG:-: FEATURES OF THICKENERS 13.2. THICKENER IJESIGJ'-BATCH PROCESS

13.3. THICKENER DESIO)<," ·COi'ITJ'-IIJOIJS Til fCKENERS

13.4. OPI,RATION OF THICKENERS

13.5. TIlICKENERS IN CIRCUITS 1).6. PROIJLE).1S REFERESCES ~, ~, ~ ~

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CHAPTER 14. SOLID L1QUIDSEPARATION· FILTRATION

14. INTRODUCTION

14.1. DES1GS FEATURES OF FtLTERS

I U . OPERA nON OHIL TERS

10 . Ci\PACITY OF CO:-nJNUOUS VACUUM FILTERS

I H . WASHING OF DEPOSITED CAKE

14 S. DRYING OF OEPOSITEDCAKE

14.6. opn~fUM THICKNESS Of CAKE

14.1. FIt TERlNG MEDlA

148. FllTERlNGAIDS

14.9. FIlTRATIO~ IN ~nNERAL PROCESSING CIRCUITS

14.10. PROBLEMS

REFERENCES

CHAPTER IS. GRAVITY SEPARATION

IS. INTRODUCTION

IS. I. PARnCLEst::rTllNGRATES

15.2. GRAVITY SEPARATION OP~RAno,..;s

15.1. JIGS

154 DlFFERE~'TIAl MOTIO"'; TABLE SEPARATORS

lS.S. FLOWING FILM COSCEJ<.'TRATORS

15.6. DENSE(OR HEAVY) MEDIA SEPARATION

15.1. GRA VfTY SEPAKA nON PERFORMANCE

lH . PROBLHfS

REFERE."ICES

CHAPTER 16. FLOTATION

16. INTRODUCTlO~

16.1. FLOTAnONREAGE/llTS

162. FLOTATION EQUIPMENT

16.3. FLOTATION CIRCUITS

16.4. FLOTAnON KINHICS

16S. FACTORS AffECTING THE RATE OF FLOTA TIO:-l

16.1. OTHER FLOTATION ~ODIiLS

16.8 PROBLEMS

REFERE.\lCES

CHAPTER 11. METALLURGICAL PROCESS ASSESSMENT

11. INTRODUCTION 17.1. Al'ALYSESorCONSTlTtiEJHS 11.2. OI,"flNlTlON OF TERMS 17.J. MATERIAL BALANCE 17.4. CIRCULATING LOAD lB. PROBLEMS REFERE~CES

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REFER£"'-CES

[n DraJl Au<lnIli ... SIandard, DR OOnJ 2000. Guide to Iho Sarnpl~ of PllrlkulOIe Makri.h: Pari J:E"i"'aliRi "",,,piing pm:i.ion, Standard. A"",noIi,,, (2000).

121 T. All"", Pani<lc Size M"""""'mm~ 21>11 <do .. Ch."",,,,, and 11011. (I91S).

(3) H. Heywood.. TIlIruI. I",mute of Chemical ElIg;nccn. 25. (1947). 14.

141 R.R. Inn; ard C.F. Colli .. Panicullltc Size "lCa'''''':'lICIlt. lnt<rpm.Uion and Appi"""ion.

JoIuJ Wiley. New YOfk. (1963).

[SI D. LiSler. M q Mao;a>ill<. Sepl .• (19SQ). 221.

(61 P.M. Guy. IIlt<:rnational Jourral of Mi .... ll'r<>oeo1!i"ll. 3, (1916), 289.

17J P.M. Guy. Sarnrling of Panicul.« M.lefial, lh«>ry on<! PnocIi«:, m"",>« Sci.ntin"

Publi"';"" Co., AmSlrnlam. (1979).

191 B.A. \\C,U .. Mincrall'rt>cessi"ll T«hnolog)'. 4th <dR., Pcr-gamon ~r,,"., Oxford. (1'1&9).

[9] A,f. T""",," 1 1 _ of Mi""r:ol Drnsinll. John Wiley and Sons.. l.ood<>n. (19S3} [10J l.W. Mcr\Ji. Sarnpliq and Wrighinj; of Bulk SoIKl$. T""", T""h PubliClllions.

CLru.t/ml·b JI.rt.ld, (I 'laS).

Pl l AS 1676-1975. Mothods r", ,he Sampli"ll of 11!1fd Coal. SWI<IaN. Assmia!ioo of

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""""'Ies.

lte)"WOO<Illl ""rodoce<l. """"",ion

roel« ror ~ PIIIIicl... To use ,be """"",ion f"'l01 Hcy",uod COD>~ U ..

diOll'<e\et of 1toe p-ojo:1ed """" do lof . particle sittin& on il> ""'" , .. ble posi!ioo), Hc

"" .... ul.ted !be ~inlt ~olumc: .. k.d,.' • when: k ... oorut>nt and • function of shape

and tho (""101 (F"Ip, A V') Re'.

Oth<f shape foeton ha,"< been proposed, ru;:h ... tho sph<ricily facwr. S. defined

m.a!bematicoll), "IS. 61:

Nominal ""I""", dian>c\Cf

_-

_-,-

d ' Nominal surfoee diameter d '

•

- diamclc"t of uphm: of "luoi w>lumc: - diamc:'cr ofo >pi .. ,e of "luoi •

..ru.c.:

>=1

(2.13)

The values oflog r(F" I['FA V') Re" r and log r(F"'p.-A V,')Re' r cor=pooding to dirm-:

"aI ... ofs/>apc facwr. k. .... 1Ii"en in Table 1.3, To use !h.i.lllble.1og [(h/p,AV,) Re"1 is colculated fiom 0 .,. .. ured .. '~i"ll '·elocily. V r. "'i"ll Eq. (2,21) fo< a Oplocri<.ol particle and

tho "lui,-a!"" Re val ... fOOM from Tablc 2,2. 'Ihe correc1ion valut from Tollle 1.3 i. lhrn

appliC<l to ,be loa! R< val"" 1(1 a.c«>un< f"" tho "",>-~I shape of ,be "",,;';Ie. Tho: partido

,ize can tot cal<ulol«l from lbi, wr=:l«I ,,,I,,,, of Re, A .imibr pruc<d..--c follow. fo.-vol ...

of 10;; [(FoI",A V .'IRe' 1 calculotcd from ".h, .... of partide site d.

I-:XO"",u l.]

5p':<01", """"""i1. "",,;"Ieo from I..oi:>ta<lo< """'" ....,plod '" .leI<1mi". tho oize <>f ii\di"id .. 1

panicle •. Tho:

."crago

1Ctmi .. 1 veloci1y of 1he particles was dc10rmined to be I ~ mmI. by

allowing .i"llie particles 10 f.1I .hf"O<lg/\ • tall <}1i"",", of "' ... Tho: <\ei\S;'y of 'be ore parti<1 .. ,,-as ~ qlm' Wld tho ,,"'-<I" . . . Icmpai01on< of2~ • C. E .. ima!c tho: approxUrut<

.. '" of tho pari;"ks,

(58)

(59)

(60)

(61)

,

F

p

Ro'

0 ,4.'(

1):1

.r) P,'

.F \"

,"

Sub<l.;'utin~ ,he d.w. ~i,-.. :

Fp ~,' . " U.OOI06' , V,l , UI , (1120_""1) .. . .

Or V'

Then from Tobl< 2.1.

log Re - 1.7143 or R< - S 1.7'1

- 2078.64

Fmm rabl. 2.3 tho OOI'fe<tion ".1 ... for Io!.: Re '''''''''J'O"O'Iina '0 • >hope fae'", of O,J ~LI3.1, • Q.00I47.

That is. lIle OOfT<">.W ,111 .. of

k'Il

~.

ro.

,he IlOf'>.Sp(!eric.l p41\icle - 1.11,3 - Q,()4.:7

-u,li%

and Re - 46.]3

Usually gravity segrq;a1ion method. or<: !!Sed to dc!onnioc: panicle oi"". Gown to 0.02

",'crons.

1.1.4. &Ji"''''/ali<m M<I/toJ _ C'''''ifut,ai S<di"""MIjon

Eq. (2.11) indic.t<. IlIat .he .. rm;'w I'docity of _1""'id< """ b< jn<~ and lh< """;"11

pmod

r<duc<d by ifIC", . . i"ll ,he ,-.1.., of !he oc<ck-ration "" IIIe perti<1e. This OM """ily be

""too,

...

both in !he laborawry and in iM",ry by.1>< """ of <owifugos (fi~. 2.4), ,,-.,.,.. g can oc ITfllaccl by r (j}' . ... tl<fC r ;. ,he

rod,,,,

orth< ~tllrifuge and", i. lIle ",,£"1 ... ,',!oc;'y. F", a >phcrial panick. ~'in~ S", ... ,' La .... Ill< motion of the partidc in the «n'riful!< <an

be expressed by lhe <qua,ioo, for Rc < 0.2;

(62)

(63)

(64)

(65)

"

Particle Size (microns)

],l.J. GaNdin&~ DUtrihlltHm

10 some OU<:I! ,,11= Ihc distributiQn i, . - . • ~ .... plot .,.., be obtained b\" plO!tina !he

lot

of!bt CUDluloliVl: lIDil<:n;iu agoinst ....

lot

of lhe ... , "1'<"'=. pr<fmobly on Iot-I""

papa (Fig, 2.7'\. S""h plot. on: knc>wn .. Gowdin-Schub:nan. pIo:s. 10 moot cues 1Iti, "",,"d

yirld. IItnlipi line. n,.,..montage of JudI plOIS is 1hat. lirni!<d numbtf of ,ieves may be uocd '" "..."'" Ill<: ";ZIO of patticloo lyi<>a bttwettl on)' lwe .i ....

,i..,..

II 01"" ind"'-> .... diolribution of Ii .... ofpatticles !hal rolll in • sample.

It is .... """'nary '" pi", both \he cumulative oversi .. and \l!ldenizc: as eaclI is lbt mirror

~oflh<other .. ...., in Fill_ H .

u..

Goudi.-Schu/mwm diSlnbuilon i.

xi_ .,

r

-

10 0(

:

r

(2.30)

wber< Y - oumulalive ... OK p<IMin& ... ~

• - """"'" ~ oj""

k _ ... p.rome\er

• _ di~buti"" poromt\ef

Toki"ll !bt lop ofbodl >ideo of !hit eqIIIIioo and ~ I~ !be:D: loKy - lotIl00 " .\o&x" . lojk or

Io&y - .1oa' " COSSTANT (l.ll)

1bi. i. !be eqUllion of. waiplline if. ODd Y on: ploltcd OIl ol<>g.<og ~e. Tho IIopo of tit< rtrlilht lin< will be: tho diotriburi"" paran>&r . . . on<! "'" int=cpt of tho ~ Ii ...

",hal y - 100 %, will be tb<: siz< panmct<r, k. Theoc _ ponun<l<1"! cba"""",,, tbe W:e of Ihc: ... pk:. 1h< diotribu!ion ~ j, • n "'''''' of tho rafll< of dilf<r<lllt """" in !bt

(66)

(67)

(68)

(69)

"

" plot of

k>a

1"11 (lIl0/R) ",,'sus k>g, should

gi"'.

strai~t Ii ... The pararn«= "rthe

Kosin_Komm:" dinnbuu"". b and x' .." obIair>O<i from lh< <lop< of the ""';lIhl Ii .. and It..

int<f«p1 II the horizonlalli .. at It - 36.19. re<poxt;"oly. TOlIClhct !hey <OO1ple1cl}' describe the ,iL:C distribuo;ioo. To ';mplify the ",lculation of It.. double

k>i.

speci.11I1'IfI/l paper i.

",-ail;obl< (R""',o.-l('onn'l<rIW<ibull 1"'1""')

,,1><.-.

,-al"", u( ,wn ... ' " '4 ","",'<d (.,.-cumul .. i,-e % I""'inlll <an be plotted dim:tJy on !he Y-",i~ A Ii"" "" 'he grap/1 paper at a

cumulativ¢ % mail'ltd

,-.l""

of 36. 79 i. j""lodo:d t" a11o,,"' .<l;mat.", <>f1P>< p>/ameter x', 111<

m<\1>0<1 of ''''''PU,inl! f", • Rosin_R""'ml", plot is ill",,,,,l<J ;" ~;,""'pI< 2.4.

Enmpkl.4

A ";"ve anaIpi ... '.owed the (0110,,'0& ... ull> (Table 2.6). PI", the daIa acoordin~ to a.udin"

Sehunm...., and Rosin·Rommlcr and

dct""",,,,,

the ","", of Ih< liz< 1I1><'ion rn.oiocd on 200

~

fig. 2.11 i. a pi'" of tho <"","Ial;'-o ~. passing <"luron in Tabl. 2.6 ,-""" •• j:<t_ The GaU<ljn·Se~uhrnan" plot is • re"", .. ~l. SU'>illJl! Ii ... thai ~-. \he fB<:hon of <nAlOrioi

p;>Min~ a 200 I"" sic,," was OXpe<l00 10 be 10.1". by mas ..

Kosin-lUmmi., plot. <"" ,imHarly bo modo oithor by calculation, Q' u,ing 'I""io] 1<>1\ raJ'<' ~"""n a< Weil>ull gtaph p.tp<t thal .. ," labout""'" <:.>kul .. """.

T)l'ieal calculO!ioos usina the data in Tobie 2.6 is illustrated in Tobie 2.7.

This <OIl ,",W bo plotled .,., ~ K'''fIII pop<1" (Fig. 2.12A) ... on Of>O<iO] Ro,in·lUmml ...

P"P<' (."ig. 2.12B). 11>< plot i. ""arty 0 .lraiKht lio<:. "hi<~ ioo;.,o" .. "'"' lho m ... ["",ti"" main«! on 200 rruorum is oboot '1(1.6 % by mass or 9.4 % pa~.

"

•

,

•

• ,

•

< •

,

_•

!

•

• ;

• _•

~ MM, U •

-

••

_•

.

,

•

• ••

••

"

'00

(70)

(71)

(72)

(73)

»

,

II

i---~·_{_1:2110.1>:},·

,

I

-

~:;·.=='I

--

..

.

_~-

-•

--- •... j

, r

....

-~

...

-

...

.,

-

.

•

~".""":i

..

I .

t

10. ~

n" '" ..

::;~=:::::

I

_I

₎

I

!,,::::;"'-

,

fEi;~;;;=;=!~~~

,

i

,

, II

~!~:lln

i II

...

-

.

..

-

....

~~

' I dl:

!!".:;,.,

= ....

!J

,"

•

_.;;'!!~

..

-

...

•

_•

Ii

_•

_:l'.,

,.

• _II

.1

.

-

--

....

t

..

:11> • • i$=,~'~::

I

,

i

!l

,"

j

• • -.

I

"

!I

;-

.

-

-...

.i":"

•

-

..

_~ _."

I

,

I

;;;;;i

:1Ii.!:!

"

.

_•

".

_•

• ,

I

.. .,-..

~~ ~:::

..

=

!

.

!

,

_I

••

-

...

..

...

..

• _I

.,

,

;;!il~ _='1I~. :,;

_-".'''.

---

...

-

,

N •

'

,

'

J

h

• ..

,

!!".

~=;~lt

_•

; ~~!:: .

i.IJ

.,

N

i

.

I

H

...

,,"-

_"~=11111

_•

";",~~,,

e ,

(74)

(75)

(76)

(77)

Table 2.9

C"",~i"" cf cyd .... i' .... <lola Ic «jUi~alen' "" ... dala using the shop: factor. 11 - 0.636

S""

P.,>i"ll ~~ Cwo % PaMing Conwn,:d Size. (micruns)

( microo

9 .

(mi<:rotu)

"

N,

117.9

.,

"

S96

m.'

"

499 S].4

"

337 377

'"

"

230 2S, I

"

•

lU 1&.9 l.4. P..,bkm.

"

0. .. obtainal <HI onaly;ing' IWIlbJing mill producl i. ~i",,", below. PI", the data using the

Goudin-Schumann and Ro,in-RammJer melhod .. hom ,he ploU ""'imok ... m ... [""'lions r<:1IIin<d Cn 200 ~ lind ]4 ;om .... recm.

S1",. "'"

feed. mass % .... ioed

"

1200 600

LS ~.o

300 ISO 75 _7S TOIaI

10.0 22.0

no

29,S ]00.0

U.in~ "'" follo"'inj: da1.a. plot • Ro>in_Rammlcr di>lrib<llion curve ..,d <lelerminc its eq ... i"".

2000 1200 8SO nuss % 4.0 9.S 125 2-3

..

₁_5.S

_""

19,0

,W

16.0

'"

13.0

.,.

10.5 ,~, 100,0

Sample> .,r!be foed 10 • boll mill .... the

prod"",

aile< IS min> of _rat"", ,,"'" .... ly....t

ond the: ,.,..,1" ""' OS

r.,uo",'",

&lima,. the rate cf rtductioo cftbe 1000 '"'" feed size duil\i the mill ~ioo.

"

Th" prod"", from • ifir.dinj: miU ""' ... rI<d e'C'I)' 30 minot .. rOt the fi ... 1IOur, then hwrly

for 4 houB.

n.:

sample> ~ ""r=ro;d I01d onol) ... yielding ... follo..-illg

"''''''II''

,i..,

(78)

(79)

(80)

(81)

C

h

apt

e

r 3

.

S

i

ze

R

e

du

c

ti

o

n

a

nd

E

n

e

r

gy

R

equ

ir

e

m

e

nt

3.I.YfRODUCTION

In n.tu .... tnir.eral' exist in 1lh)"Si«J and chemical eombinalioru "'ill> each OIher. To....,....te

min<rol. of eommrn:ial in",re" ftom'''' 00" nx~ 00th p~y.ieal and ch<",iclll ~1lod3 or<

<mploy«l, Most tnifl<'nl' an: mined in til< form or

Iari!.

ro<k •. 01. ... like til< ilmenite. rutil ••

ziwon. 1<Il00 ... ,). mi ... l' 01 11l.,·ial plOC<1" deposits of Ilold .... found clc<imat«l

0ItI0DV' S?nd in

be

""..,. '"

in riv<rbod>. To """" .. the: ~. in tho 00>1 rod.",. they

ho,·

.

to

be crushed aDd e"dl ~un<l. When a fIl4Xim"", omo"", of !he mir>etltl of ino=.. i,

....,....

,

«1

by oomminution from thc: par<n1 ro<k.!hat "'" i. 1lIua\ly bo"'T1 U tho liberation Ii",. The

Illm of comminu,ion i. '" m.tXimi .. the Iibe .. 1ion of til< min<ral from the boot rock. Uwally

the COIIC<ntralion of useful mi...-al. in 1>051 ro<k ... low. theref"'" large tonr'IageS of host

ro<k5

ha,·. '"

be mined '0 rt«>"<-r >umeidll quantities of \he useful mincnI 10 """'. til<

OperatiOD CO!lIlIl<-r<ially ,·isble. The fItS' step in !be reco,''''Y proces.< of mineral. ftom

"It:

00"

ro<ks thet<-fore i. 10 ~""" til< Ii", of rod by orwhinl: and llrilKiin\l. The equipmen, used and

thri, ope""ion .. " ~i",",ood in ,uMeq"".t chople .. ,

J.I, lln ll G of Slu R«Iuollon p, ".." ..

The pt'QQtl& of oi", .-..:II><li"" i. ""rmall)' do,i&n«i to 1.\:0 pi .... in ,inlli' . . . . open

eireuil. sinal. SIal!< closed d«uil 0< mullipl.

'!ai'

opot! or ,Iooed ci«U;1 In"""" cues 1

combination of tho .. _hod .... adopted, In • • inill. '\agO, lingI. paso, """" d«uil size

r.<h><tion """",.ion, the prod ... " con,i ... of • ~g. of pankle si",. whioh .. Idom ",hi" ..

!he do,ired

doi=

of liberation.

II""".

oeoood or e,'dl third su.,;es of size ~uctiOll .... 01\ ..

1'!eC0S!Il'Y '" I"""ebi .. l)' ~UC< til< f<!l'\Iini"i 1*11<le .l .. 10 libe-rolt mi ... ) puticl . . to on

otCcptablc dei= (Fill. ], I),

III olO!l<d 'i«":,. tho prod"" from tho ~ of size ~ucti"" i. ~'«I imo relatiwly

ro ...

ond 000lX f"",iOIll. The ooarx:r Iiaclioo is lhrn coll«:ted ond m:ru>hed in .be """" UlIi •

.. seen b Fill. 3.2. In.., doing tho load WI tho equipm<rlt for .ize ~"""'" i. i""ruled..-.l a

d« .... inll' load i, cstabli5h«l, but the toW rrumbor of..ruts ""Iui~ fo< ob!";ni"i!he """"

doii'« of .iz< ~uclio i. 10".

Se>'eraJ options in <bill" exist in oIosod d rcui. llrindinl:

"'_ups,

The.WI) ""''' """""""Iy

used do,ices for .iz< redUdion are the o""hen ..-.IllrindilOj mill,. The orushen ore normolly

fN with rooks, up to oboo, 1 ... 1 .. in lize. "hilc tho grinden ... ually fod "ith rocks

<rusIItd do"" to • nuximum .ize of about SO mm. Lori" rock, p.-.,ducN .. !he mi .... ore

initially

....,....

.

«1

by llrizz!;"" ""'ken by hamme" and tbcn fed '0 tho <ru.non

The ",""!lani.,,,. of .ize ~""ion d"';na cru,hina ond irindini .... diffo-mu. The ,hi<{

diff .... ru beifll! tho1 in crushing operation. tho ,i", ~uction i, more by compres,ion and

impo<t and 1_ 11)' attri\\orl "lIile in grilKiing. tho forte' of attri.ion .... m""b 1ifUI .. · The

grilKiing operation i. mbOT compl.x and ilS <XI",pI.~it)' WI rouahly be illustrated by

Fill

.

3.),

Spberi<;al bo.lI. or cylilKincol rods .... """'I)" ... the &rind;_1: modi>..

no...

media

c.,code within & mill ond impinge on tho "'" thOil pro"idi" , . <rushin& ""tiOft. AI tho ball,

(82)

(83)

(84)

(85)

lbe >a.iuc of W. C&Il be oonsidertd to be ilIdepen<Ieo! of illY classifier placed io !be omuil

The termJ f and P .... usually writ!M .. flO and rIO. the ",1>oaip!S der>o!illll the *"~ oi.ze of

feed find prodUO! ' .. pt<O!i .... ly!hroo.o!;h "hid! 80% of!loe f=I and proOxt ... The termJ

*

one!

R

....

dime:nJionI~

.. , .. \Jie ... bet 10

,",,~"i1U

~IOO

mic:roru.

By defonitioo!be opeci& jlrindinl eneraY il!he """'lP' ""Iuirtd per w>i! IlWII oflht rod<.

The opcciGo arlndina ... 1I)' of I ~ar minmol il wriuen ""

(loS)

NOTE: I. kWMIl600- JoWcoil.

2 While 80% _illll • pooni<:uJar sieve is _oed .. IIUdard fur de!<;rmioillll

!be W<rl: I"""", .. rt<Xm._drd by Bond, """"' .... 75% imteod

In

Bond·,

equation. (Eq. (3.3)). the griroding eneri)'. Eo. ""Iuinod for Ii .. rcdu=!ion arrod,.

in ;odllAiol mmbli"ll mills WII baed 011 mill Wft P"""'", Pw, ond Oft mill """";!y (Q) The

.. lation>hip ~ ""-

_.un

10:

_

'M.

Q (3.6)

For..,y rook ... r""' !be ... C ""Iuind for romminutioD may be <kkrmiDod.. provided

!be Wori index WI;' known.

~ mmual ~ ond di";"iqpolion of. rook with • hammc:r, or durio& mcclIanicaI

oruohin.!: cpc::micm. the size .... ""tion of 1 _ oizcd roou ond ""'" is llIOOtI.y by sbatp impact

Ktion. ODd las"" by !be imJ-"i on<! ottritiOD ""pcrico<oil iD !umbllnf mill .. The equoi:ion

used by Bend ;0 inappropiaI< IC d<Io:nni ... !be energy «quirtd rot crushing. To cover ihiJI

dis=pmcy Ob ond M';imo [9) f"""" tlooa iro sucIo <UeO !be <xpota:>d of n (loS) in equation

3.1 shonId be tq>I...! by (!+[WD. Thio equ&Iioo "",",,0 IC !be Boo:w:l equ&<icn (equation 3.3)

by Wcina the vol .. of B .. 12 and iro\egmlna, thus;

(H)

wbiclI ift effa:t is Iht Bond equatiOIL

Bood". oriainol milk on eJ\Iblishing the

"""II)'

for oi ... oction wa es\Obli!hed in I 2.44

m (I foot) irolenlal di ... "'"' ¥rindin3 uv..oow type boll mill. Dwb< i, III>W exp,n.d

_ ! b e derived empirical equati"" i. applicable IC

hiah

I>esou .. roller c:ruMcrs "bore

one: otagc op<iI oircui! taka 1'1 ... A...tina to K1ym<>wsky """ Lin [tSl indiCOlions ... thai

!he: Rininll"" exP" "·M,1l - )( (lIP -11F~ is mote opplioabl. for IIize teduotion by high

(86)

(87)

(88)

(89)

"

Alkr the o<riU by the "";king 0< inpul pero;julum, ",ben the block Of . . "I Of rrlIound

pcoduhmt

'''in&>

."'~ from it. pooitiQa orm(. \hi: ,'.Iocity of the , . , _ pendulum woWd

~,

where II. - IheVMicaJboight.no.inedbytheblockpendulLll'll....!

•• ' - Ibt velocity of"'" I>I<>ok Of tebotu>d pendolom oftet ;mp.cl.

oro;Ilbe o:orTeSpOnding energy ofreb:Jund will boo

(3.1~)

(3.16)

After the impecl, the vclocity orllle

suikina

pendulum dca 5" 7 and V,'MW will be jlive:o

'"

_•

_(v.'

_-

_v

_.'

_l

Vs - vo - -. . (l.l?)

•

WO- •

vo' - the velocity or .... bIod bd"", impo<t

v,' - the ~lo<ity oftht Jlriking pendulum.uw >"'1*1

AI II>< initiol velQcity of tbe rrl>o>und bIo<k pcodul"", i, :we. lPPlyioll NewI<>ol'. J..&w of

"""..,....;"" of <td..,. the "",trIO;"'! of fnlitution "'ill boo,

, ,

• • (V, _V,)

•

"

(l.II)

Tho CIlCIJIY for

crushin&

Eo" tbe diITcren«: tid",=, "'" cDa'f.l'

"r

tbe input ptnduIwn and !be tiKi" oflhe ",bound pendulLlm ond is COIDpIII<d from the followina; txp'C .. ion:

(3.l9)

Uniu: E'.nerirtemu(ll)- k\\'h/t- l6OOkJlt

M...

_

1<3

n..,1lIuecf. - 0- 0.2

Tho n:ouIts obIaintd "jib the \arjeI' ..,"';1 blocl: ba .... been fouod 10 agree Vltll ""Ill Ibt

ttlCr8Y C<>nSu/'IICd ill AUMSo "'II< and Semj.AIII<>QtMW Grit>iina (SAG) mills. while n:sulu

from the omaIlcr onvil ~ more .. ith ball IIn<l rod ",ijl O<ITllnIioutioo ,~, Tho

(90)

(91)

(92)

(93)

(l.B)

In .... Bond «I ... io ... fO«! F is the ~ to the iJindilli ,ircuit and the product P. i. the:

prodoct fiom the: i!indina citt"'t. In on opal ,in:ui, this i. straightforward bu! in • c100ed

cif"Olli, mill. where. classlfier;' irulallod '0 return the <:OW>< fraction to the mill, !he work

i!>de>: i. b;>oed "" .... work dono in rmucina:!he size of the ."" ... fcod··, that i1. th< oriSinai

f .. d plu. the coane frx'ion from tho product "'i>""'Lod at the cl4Mifier and mumtd to the mill fcod.

n..

oprnt'ing ,,,,rk ioo.. i. uord for:

L Recordina: mill perfunnancc OIl • ",KUI..-twi. (b<>url),. Gaily etc.)

2, Con'"",it\i cumnt pcrfonnancc with historical d.1I J. Comrorinl! cir<:uit:! in multi-cir<:u.i, plall"

Si""" the optnti"ll worl ioo.. i""lud.. motor,

dri,'.

and i!irx:lin& incffici""ies. it i. 001 dire<tly <OtItp .... bl. to the W<lf' ;00.. ob\aiDOd from loron,.,.,. ~Iity ... , Ifmo<of and

drive lewes .... takeo into .':<0",", then fr.e openting i!ld<. divided by the l.bor>.tory

irindability work index .... c"" be ttsod ... tneaS\Il'e of grir>ding dlicimcy in .... pi""".

(J.24)

w~ Woo: ~ op<n';"i work i!>de>:. oolT<"C1od

ro.

IlOO·JIoIHIord condition. and """.

optimum fetd,

w, ttn - I.bor:>.tory i!indobility w"rk index,

J.J.J 8mod Rt>d ,1/;1/ Stondm"d

r

.

"

Standard conditions for <lctcrminini the: ",ozk index of rod mills t.m<kr loboralor)' oor>d;,iQn!l

~.

Mill Si.. _ J05 mm (inlemal diamelcr) • 610 mm (internal knljlb) with _ ' .. type lini"ll

M .. terial Dry mir.eral

5i.. _ redocedtoIOO %<IJ2001""

Quantity _ 1250 em ' (tlIpp«! clown to ii~. ",producible bulk d ... iW)

(; . 38,1 mm di • • 0.53 m loni ,,..,1 f"O<bplu.

2 x 4 •. 5 mm dia x O,S) m loni .teol rod.

total mas • • 3338

'<II

Mill Rota,i"" _ 46 =Imil\. 100 % circul.Uina klad.

(94)

(95)

(96)

(97)

7. Corncti(}ftfociur: F7 Mill ~

The arindina .fficitoe}' chanaes";!h mill diameter. The change ... from the eIwlgc iD

po ... dro""" by tho mill ond tho tl\ang<

u

mill _ i l f with

wOll><ln.

The oo=i:OOn foctoT i:I

8iV<1l

u;

(

'~

)

"

n

_

o

f ... D< l.llm

F7 - 0.914 for D ~ HI m (3J2)

~ the m,U d~> D, i. in ... 11 .... b<en _ by Ilond

u...

f ... mill . . . IbM

HI Ill, tho reda::tiarl in grir"04in& ener&Y reoulting from mill dioo'r"!el ... ond tho

COJl'<I<:tion _ i. constant at tho 3.11 m nl ... ofO.914.

"- C""",,,ioIofoctor FI! Rod ),.fim~

The oor=:tion _ for rod millina i:I complex ODd oIcpcod. 011 tho feed JAcpwlllioo:o. IIond

auggestJ twI) conditions;

1. .'", .. rod mill only applkotion, .... on <fJ"ociency focto< of 1.4 """'" the foed i.

produced by open ,irc";l cruohina. ond "'" I _ of 1.2 w!Ie1I the mill feed i.

prodO<i:d by <lox<! cimJj(

<nI!hina

.

2. For • rod mill·t.11 mill <in:";~ &0 '''' 'Wly. mill d i _ o:omction for the b&ll mill.

If lhe rod mill feed u prod...:] by open ci=il cn"'ri"i "'" I _ of l.2 for the rod mill >lOge only. If Ill< rod mill f=;[ i:I JO% ~ 12 mm or ..,.. (<0.11- from • d~

cifoJil <rIMer) do DOt apply • rod mill .fflCiency facto<. 0lhe1 o:rrre<:Iion fattorJ sucb .. mill diameter ond m:!uctioo ratio ho,,~ .. do

lPPly

.

The WOMaint~ in this correo:tiorl f..,tor f'O'n.!Ioa1 illla li1ll. val ... iD calouJotina. Wee

and \be .lfocienc~ of,.om rod mill pe<f..."..,..;e. lbus \be test wort. index val"" multiplied

by tbt prod.." of1he oOIl«:li"" factoro will fJi'<lvi<I< on eobmate ofllot true (pla..,O

"""*-

index

....

(3.33)

he",," r", ..,...!ilion not applicable obouId be tak ... I.

The Bond W",t Index ,'Ill ... c/wop with the si ... oize ~ dllring .. porUculor __ For

""",,,pie. in_d of ~ the oo:r<>eZI ~ tlirouBb wbich &0% of the "'" P" = ,

u..

"""I

size 1htou&h ",hich 15% "fthe ore p" .... may be ch<>oen '" oW, I por\iculII' condition ofmill

opemiOll. Bond',

""&ina!

upteS$kon [or

u..

work iodu i. _ IlII BO% o[ the onaterW

PUS;"lI • """"'" ,i .. , Thi. hos

""w

b<en adop<cd as tho _ _ Any do-.-iatioro from !hi.

rlaRlanl would fUjuire tho delcnnillllion of ... ' ... odin& "'IlIi .... """"'. The method of

(98)

(99)

(100)

(101)

oo· ... i'" i. n>:Ordod. TIll. "... Moo IIIK>uld be equal to tho nru, Me at a eirt:u1atilli lo.d of2~0%.

10, The oo'<J>iz< 1¢nJl"i rot. COO>Stall~ k. i5<.kuIo1«1 """iii tho <quat;"",

k • n(ln M, _lnM.,.)

N

- number of mill ,....'ol"Ii""" pet minute

- nurnb<f of mill =-'olulio", in the fi"I "' ..

).to. - ... ofl«I ..,reen o,·= i •• afu:.-lOril>dina

)..t., - Ina . . ofto't ..,rmt ,w"";zo at the

beiiMi"i

of tho pil>dins toot

(l,J7)

II. The toW number of mill ,....·olulioN f'" :he: K<C>I>Ci ilil>dina test (N,) i. clicW.,,,, from

11>0 equati",,:

N

,

0 .38)

12. The mill i, loaded with the occond c!wgo and irirw:l for N, .. >oIuli"",,

13. Aft .. (Pindillj!. tho rntu. mill charge ;, ",rernc<I <>II tho test "'''''''' and the oo .... izc

ond und<:nizc weighed, The

o,

'

em..:

IIhouId be oppro.imatdy equal to (2.SMI3.S) and

It" maD of the unders.i ••• M",. should

be

"W"xima1<ly equal to MIl,S.

14. The .i ... IY'i. of the 1<01 OCreeJl undersize i. deocnnine and the 80% "",",ina oitt

(PIO) of the prod"" calculaled,

I S, The ne", w>denizc per mill ",,·olution. G. in the oec«od a:rind ;. Ibm determined

u<in&

tho equation:

,

M. __ M(I_m,)

G . 3.5 (3.39)

N

,

16. The ore WorI< Inde. i. then calcul .. '" ",illi the &nd formula (Eq. J.ll~

Thi. rn<thod """" .. the Ii"", o[ """,uromrnl and

"ncr.

!be on: i. " " " ' -

Ii,'"

"'..,... inde. vol""" "ithin 7Y, of tho Bond method. Howe".,. "'~ tho ore contaim 110ft and

Iw-d OODlponrnts, • '"'" Bond ..., ",;11 110, . . . .-..:irculatilli I"", .. fuclI i. oompo.ro

p«<1omi...,~y of .... harder componenl ond brn<e "ill ~'" • higher WorI< IndeJ<

,-..1""

""",i.,,,,,

"ilb c\osro drcult Brin<!il\i- Sir>e< the Mqd>.linm·ic method ""'. lhe!lllme [..ro to

"""~ ilindin~ step.. thi, biordor material in .... e;n:wati"i l<>ad i, "'" ,imulated and

he"".

th<

metbod "'ill

ii'·.'

10"'" WorI: Index

,-al.,..

1. M .. J,,"'~ lUl"I • ~OIt-._d.n ,.iU.otd < •• ,,~

If. 0Iandard Bond mill i. "'" .. -allable then an approxirnat< Wor\;: lodex val"" can be

(102)

(103)

(104)