FLOTATION

frothers

when = 0o, cos = 1, Gflotation = 0, no flotation

when = 90o, cos = 0, G = -lg. full flotation

Thus, flotation reagents can be classified into

a) collector (decreases G)

b) frother (no or negligable change of G)

c) depressor (increases G)

water

bubble

particle particle

water

initial statefinal state

flotation

(a part of sphere)

bubble

Gflotation= Gfinal- Ginitial = [sg - (sl+ lg)] A

sg = sl+ lgcos

flo t4

Role of frother

1. Gas dispersion

2. Froth formation

3. Speeding up flotation

4. Improving selectivity of flotation (by interaction with collector)

pulp

froth

frother structure with depth

frother structure

H. Khoshdast, A. Sam, Flotation Frothers: Review of Their Classifications, Properties and Preparation, The Open Mineral Processing Journal, 2011, 4, 25-44 25, 1874-8414/11 2011

Other classifications of frothers

H. Khoshdast, A. Sam, Flotation Frothers: Review of Their Classifications, Properties and Preparation, The Open Mineral Processing Journal, 2011, 4, 25-44 25, 1874-8414/11 2011

Neutral frothers applied in flotationLaskowski, 1988 (with some modifications)

Group Frother 1. aliphatic alcohols

a) linear from amyl to decanol

b) branched iso-amyl methyloisobutylocarbinol

c) with additional group diacetone 2. Cyclic

a) linear cyclohexanol b) branched terpineol

3. Aromatic cresols xylenols

4. Alkoxy-hydrocarbons 1,1,3-trietoxybuthane

5. Polyglycols

R(X)nOH R=H lub CnH2n+1 X=EO (ethylene oxide), PO (propylene oxide) BO (butylene oxide) from 3 to 7

Other classifications of frothers

Class Property of aqueous solution

Liquid-gas interactions at

flotation concentrations

Froth/foam

Surface active

Form colloidal solutions (fatty acids

amine, sulfonates, sulfates)

Stronly reduce water surface tension

Form two (foam) and three (froths) phase

systems

Form true solutions (alcoholes)

Change aqueous surface tension

Form two (foam) and three (froths) phase

systems

Surface inactive

Organic compounds forming true solutions

(ethyl acetal, ethyl diacetone)

Do not change aqueous surface

tension

Form only three phase system (froth)

Inorganic electrolyties Increase surface tension of water

Form weak foams and strong froths with

hydrophobic particles

Frothers classification (Lekki and Laskowski, 1974)

0.1 1 10 100 1000frother concentration, mmol/dm 3

0

20

40

60

80

su

rfa

ce

te

nio

n,

mN

/m

MIBC

CMC

Aston et al., 1983

CMC – critical micellization concentration

MIBC – metyloizobutylokarbinol

Properties of frothers CMC

a b c

Collector ions can be present in aqueous solution as free ions(a), premicellar species, (b) spherical micelles (c).

Structures appear with increasing surfactant concentration in aqueous solution. Symbol o denotes ion appositively charged

to surfactant ion

Properties of frothers

0 4 8 12 16 20frother concentration, ppm

0

0.4

0.8

1.2

1.6

2

bu

bb

le s

ize

, m

m

MIBC

CCCLaskowski, 2004

Tucker et al., 1994

CCC

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 0.02 0.04 0.06 0.08 0.1

Sau

ter

mea

n bu

bble

siz

e, m

m

frother concentration, mmol/dm3

CCC95

bubble coalescence

minimum bubble size

Data of Finch, J.A., Nesset, J., Acuna, C., 2008, Role of frother on bubble production and behaviour in flotation, Miner. Eng., 21, 949–957. CCC95 denotes 95% in Sauter mean bubble size reduction compared to mean bubble size in water only. Plotted by Kowalczuk, Ind. Eng.Chem. Res., 2013

DF250

Atrafi et al., 2012, Mineral Eng., vol. 36-38, 138-144

in flotation important is dynamic surface tension

Relationship between flotation selectivity coefficient a and concentration of CxPy frother. ppm = g/dm. Note location of CCC. Kowalczuk, Ind. Eng.Chem. Res., 2013

0 20 40 60 80 100 120100

101

102

103

104

105

106

C1P3C1P5C1P7C2P5C2P3C3P3C3P5C4P1C4P3C4P5

frother concentration, ppm

sele

ctivi

ty o

f flot

ation

a

CCC

CCC vs frother dose

HLB (Hydrophobic - Lipophilic balanse)

HLB = 7 + hydrophilic groups – lipophylic groups

Hydrophilic groups-O- 1.3 -OH (free) 1.9-OH (sorbitan ring) 0.5-SO4Na 38.7-COOK 21.1-COONa 19.1-COOH 2.1-SO3(H) (sulfonate) ~11-tertiary amin 9.4-ester (free) 2.4

Lipophilic groups -CH, –CH2–, CH3–, =CH– 0.475-(CH2-CH2-CH2-O–) 0.15

HLB Application

1.5-3 Antifoaming reagents

3,5-6 Emulsification reagents

4-10 Frothers

7-9 Wetting reagent s

8-18 Emulsifikation reagents (oil in water)

13-15 Detergents

15-18 Solubilization reagents

Application of surfactants depending on their HLB

MWHLB

MWHLB80014.105

71.209CCC95

CCC vs HLB

Kowalczuk, Ind. Eng.Chem. Res., 2013

0.0

1.0

2.0

3.0

4.0

5.0

0.000 0.020 0.040 0.060 0.080 0.100 0.120

CC

C95,

mm

ol/

dm3

HLB/MW

Aliphatic alcohols Polypropylene glycol alkyl ethersPolypropylene glycols Commercial

DFI and other

0 2 4 6 8 10 12 14 16

nCeff

0

100

200

300

400

500

600

700

800

DF

I, s

dm

3/m

mo

le

0.0

1.0

2.0

3.0

4.0

1-C

CC

, m

mo

le/d

m3

0

40

80

120

max

, %

0.0

0.2

0.4

0.6

Jw

,=

25

%, cm

/s

DFI ( )

1-CCC

max

Jw.=25%

Comparison of different frothers properties (DI, CCC, Jw) and ability to mechanical flotation max.

They are similar (Szyszka et al., 2008)

Quartz flotation in the presence of different frothers (Szyszka et al., 2008)

Drzymala, unpublished , 2013

a

ar

)100(

a – selectivity coefficient of flotation – useful component recovery in concentrater – non-useful components recovery in tailing

70 80 90 10050

60

70

80

90

100

Cu recovery in concentrate, Se, %

rec

ov

ery

of

no

n-C

u c

om

po

ne

nts

in t

aili

ng

, Se

no

, %

LUBIN copper ore

lab. tests, rep. 174

a=101.3

30 g/Mg

alfa-terpineol

fractionated flotation

50 g/Mg

20 g/Mg

Drzymala, unpublished , 2013

Frother family Type n m HLB MW g/molCCC95,

mmol/dm3

Aliphatic alcohols Cn

1-Propanol 3 7.48 60 3.9331-Butanol 4 7 74 0.8511-Pentanol 5 6.53 88 0.2841-Hexanol 6 6.05 102 0.1081-Heptanol 7 5.58 116 0.0691-Octanol 8 5.1 130 0.0622-Propanol 3 7.48 60 5.1172-Butanol 4 7 74 1.0412-Pentanol 5 6.53 88 0.3412-Hexanol 6 6.05 102 0.1082-Heptanol 7 5.58 116 0.0782-Octanol 8 5.1 130 0.0623-Pentanol 5 6.53 88 0.4663-Hexanol 6 6.05 102 0.127

Propylene glycol ethers CnPm

Propylene glycol methyl ether 1 1 8.28 90 0.489Propylene glycol propyl ether 3 1 7.33 118 0.246Propylene glycol butyl ether 4 1 6.85 132 0.159Di(propylene glycol) methyl ether 1 2 8.13 148 0.176Di(propylene glycol) propyl ether 3 2 7.18 176 0.091Di(propylene glycol) butyl ether 4 2 6.7 190 0.063

Tri(propylene glycol) methyl ether 1 3 7.98 206 0.073Tri(propylene glycol) propyl ether 3 3 7.03 234 0.047Tri(propylene glycol) butyl ether 4 3 6.55 248 0.028

Polypropylene glycols Pm

Di propylene glycol 2 9.25 134 0.396Tri propylene glycol 3 9.125 192 0.172Tetra propylene glycol 4 9 250 0.088Poly propylene glycol 425 7 8.625 425 0.014Poly propylene glycol 725 12 8 725 0.010Poly propylene glycol 1000 17 7.375 1000 0.008

Commercial

FX120-01 6 6.05 102 0.108DowFroth 250 DF250 1 4 7.83 264 0.038DowFroth 1021 DF1021 1 6.7 7.48 420 0.014FX160-05 3 2.5 7.11 207 0.072FX160-01 1 3.8 7.86 251 0.048F150 7 8.625 425 0.014F160 4 2.5 6.63 217 0.037

Frother properties

Zhang, W., Nesset, J.E., Rao, R., Finch, J.A., 2012, Minerals, 2, 208–227.