FLOTATION

OF MINERAL

MATERIALS

Class Example Applied collectors

Non-metals and solids withsignificant natural hydrophobicity

sulfur, graphite, coal, talc hydrocarbons, nonionic liquidsinsoluble in water

Native metals and sulfides gold, chalcocitechalcopyrite, galenasfalerite

xanthates, aerofloats

Oxidized minerals of non-ferrousmetals

cerusyte, smitsonitemalachite, tenorite,cuprite

xanthates (after sulfidization)siarczkowaniu), anionic andcationic

Oxides, hydroxides and silicates hematite, ilmenitecorundum, cassiteritechromite, feldsparskaolinite

anionic and cationic (with andwithout activation using metalions)

Sparingly soluble salts fluorite, barite, calcite,apatite, dolomite

anionic and cationic

Soluble salts halite, silvinite, carnalitekiserite

cationic, seldom anionic

Classification of materials according to their ability to flotation

Class 1. Naturally hydrophobic materials

Graphite, talc, sulfur, some sulfides, coals

collectors: apolar compounds which increase hydrophobicity and speed up flotation

H

H

H2C

H

H

H

OHH3C - CH

CH2

weg2

Simplified model of coal unit

0 2 4 6 8 10 12 14

moisture content, %

0

10

20

30

40

50

60

70

80

co

nta

ct

an

gle,

deg

ree

captive bubble

sessile drop

flotometry

bubble attachment

r

80 82 84 86 88 90 92 94carbon content in coal , %

0

20

40

60

80

con

tact

an

gle

, d

egre

e

coal

Hydrophobicity of coal vs. coalification degree

Contact angle depends on method

of measurement

100%

80

80

80 100%

100%

60

60

60

40

40

40

20

20

20

0

0

carbon

cellulose

lignin antrac ite

graphite

brownhard coal

0 2 4 6 8 10

0246810

zeta

po

ten

tia

l, m

V

+

oxidized

anth

raciteco

king

sub

bitu

min

ou

s

pH

Zeta potential (and electrical charge) depends on coalification degree

Coalification vs H, O, and C content in natural carbonaceous matter

Class 2. Native metals and sulfides

A) Metals occurring in nature: iron, mercury, copper, gold, platinum metals

B. Sulfides:

lead (galena, PbS)

copper (chalcocite, covellite, chalcopyrite, bornite)

silver (argentite)

zync (sphalerite)

Class 2. Native metals and sulfidesTable 12.36. Collectors containing sulfur applied for flotation of sulfides (after Aplan i Chander, 1988)

Collector type Formula Chemical name Manufacturer anddesignation

Mercaptan R–SH Pennwalt, PhilipsDithiocarbonate(xanthate) R–O–(C=S)–SK

R–O–(C=S)–SNapotassium ethylsodium ethyl

AmCy

303325

Dow

Z–3Z–4

potassium isopropyl

sodium isopropyl

potassium butyl

sodium isobutyl

potassium sec-butyl

sodium sec-butyl

potassium amyl

sodium amyl

potassium sec-amyl

potassium hexyl

322

343

–

317

–

301

355

350

–

–

Z–9

Z–11

Z–7

Z–14

Z–8

Z–12

–

Z–6

Z–5

Z–10

Trithiocarbonate R–S–(C=S)–SNa Philips (OrformC0800)

Xanthogenformate

R–O–(C=S)–S–(C=O)–OR´

R=ethyl, R´=ethyl

R=izopropyl, R´=ethyl

R=butyl, R´=ethyl

Dow

Z–1

–

–

Minerec

A

2048

B

Xanthic ester R–O–(C=S)–S–R’

R=amyl, R´=allyl

R=heksyl, R´=allyl

AmCy

3302

3461

Minerec

1750

2023

Monothiophosphate

(R–O–)2(P=S)–ONa Amcy 194, 3394

Dithiophosphate (R–O–)2(P=S)–SNa

(R–O–)2(P=S)–SH

sodium diethyl

sodium di-isopropyl

sodium di-izobutyl

sodium di-isoamyl

sodium di-iso-sec-butyl

sodium di-methylamyl

cresylic acid+P2S5

AmCy (Aerofloat)

Na Aerofloat

Aerofloat 211, 243

Aerofloat 3477

Aerofloat 3501

Aerofloat 238

Aerofloat 249

Aerofloat 15

Dithiophosphinate (R–)2(P=S)–S–Na AmCy3418

Thiocarbamate R–(NH)–(C=S)–OR´

N-methyl-O-isopropyl

N-methyl-O-butyl

N-methyl-O-isobutyl

N-ethyl-O-isopropyl

N-ethyl-O-isobutyl

Dow

–

–

–

Z–200

–

Minerec

1703

1331

1846

1661

1669

Thioureaderivatives

(C6H5NH2)C=S(thiocarbanilide)

AmCy Aero. 130

Mercaptobenzo-thiazole

Seria AmCy 400

0 2 4 6 8 10 12pH

0

20

40

60

80

100

flo

tati

on

re

co

ve

ry, %

pyrite

10 M KEtX

2x10 M KEtX

-5

-4

Xanthate flotation of pyrite

Class 3. Oxidized minerals of non-ferrous metals

cerussite (PbCO3)

vanadinite (Pb5[Cl(VO4)3])

anglesite (PbSO4)

malachite (CuCO3·Cu(OH)2

azurite (2CuCO3·Cu(OH)2)

chrysocolla (hydrated copper silicate)

tenorite (CuO)

cuprite (Cu2O)

smithsonite (ZnCO3)

1. Sulfidization

Approaches:

2. Flotation using either cationic or anionic collectors (as in the case of oxide-type minerals)

Class 3. Oxidized minerals of non-ferrous metals

Class 4. Oxides and hydroxides

Consists of simple oxides (Fe2O3, SnO2), oxyhydroxides (AlOOH) as well as complex oxides and complex hydroxides (spinels, silicates, aluminosilicates).

Table 12.38. Influence of structure of silicates on their flotation with anionic and cationic collectors (after Manser, 1975)

Silicate groupCollector

orthosilicates pyroxene amphibole frame

Anionic good week none none

Cationic satisfactory* satisfactory * good very good

* Flotation depends on pH

2 4 6 8 10 12pH

0

20

40

60

80

100fl

ota

tio

n r

ec

ov

ery

, %

albite

quartz

varous minerals

Class 4. Oxides and hydroxides

Oleate flotation of oxide and silicates

10-08

10-07

10-06

10-05

10-04

10-03

10-02

10-01

1000

amine concentration, kmol/m 3

0

20

40

60

80

100

18

QUARTZ

16 14 12 10 8 6 4

Class 4. Oxides and hydroxides

Amine flotation of quartz

Table 12.44. Solubility product (Kr) for selected compounds at 293 K (after Barycka and Skudlarski, 1993)

Compound Ir Compound Ir1 2 3 4

Fluoride sulfite

CaF2 4,0·10–11 BaSO4 9,8·10–11

SrF2 2,5·10–9 SrSO4 6,2·10–7

MgF2 6,5·10–9 CaSO4 9,1·10–6

Chloride sulfideAgCl 1,8·10–10 HgS 1,9·10–53

PbCl2 1,7·10–5 Ag2S 6,3·10–50

Bromide Cu2S 7,2·10–49

AgBr 4,6·10–13 CuS 4,0·10–36

PbBr2 2,8·10–5 PbS 6,8·10–29

Iodide ZnS 1,2·10–28

AgI 8,3·10–17 NiS 1,0·10–24

PbI2 7,1·10–9 CoS 3,1·10–23

Carbonate FeS 5,1·10–18

PbCO3 7,2·10–14 MnS 1,1·10–15

ZnCO3 1,7·10–11 cyanideCaCO3 7,2·10–9 Hg2(CN)2 5,0·10–40

MgCO3 3,5·10–8 CuCN 3,2·10–20

Hydroxide chromate

Fe(OH)3 4,5·10–37 PbCrO4 2,8·10–13

Zn(OH)2 3,3·10–17 BaCrO4 1,2·10–10

Mg(OH)2 1,2·10–11 CuCrO4 3,6·10–6

Class 5. Sparingly soluble salts

2 4 6 8 10 12 14

pH

0

20

40

60

80

100

reco

very

, %

fluorite

SDS

DDA

NaOl

Class 5. Sparingly soluble salts

NaOl - sodium oleate, DDA-dodecylamine, SDS,- sodium dedecyl sulfite

Flotation with potassium octylohydroxymate

Class 5. Sparingly soluble salts

0 2 4 6 8 10 12 14

pH

0

20

40

60

80

100

reco

very

, %

chrysocolla

bastnesite

calcite

barite

10-06

10-05

10-04

10-03

sodium oleate concentration, mol/dm3

0

20

40

60

80

100re

co

very

, %

calcitefluorite apatite

Class 5. Sparingly soluble salts

Class 6. Soluble salts

Table 12.45. Sign of surface charge for selected soluble salts(after Miller et al., 1992)

Salt Surface charge sign Salt Surface charge sign

measured predicted* measured predicted*LiF + +– KBr – +

NaF + + RbBr – +KF + + CsBr + +RbF + + LiI – –CsF + + NaI – –

LiCl – – KI +NaCl + – RbI – –

KCl – + CsI + +–RbCl + + NaI·2H2O +CsCl + + K2SO4 –**LiBr – – Na2SO4·10H2

O–**

NaBr – – Na2SO4 –**

* Predicted from the ions hydration theory for inos in crystalline lattice (Miller et al., 1992).** Hancer et al., 1997.

10-06

10-05

10-04

10-03

10-02

dodecylamine hydrochloride, kmol/m 3

0

20

40

60

80

100fl

ota

tio

n r

eco

very

, %

KClK2SO4 Na2SO4×10H2O

Na2SO4 NaCl

Class 6. Soluble salts

scale

capillary

Hallimond flotation cell

air

drive

Laboratory Mechanobr flotation machine

FEED

AIR

Denver DR flotation machine

CONCENTRATE

AIR

WATER

CELL

FEED

ODPAD

Jameson flotation cell

TAILING (~0,01 m/s)

gas(0,005-0,03 m/s)

FEED(0,01 m/s)

air bubbles(0,5-3 mm)

phase borderFROTH LAYER

FLOTATION REGION

concentrate

water(0,0005-0,003 m/s)