massimiliano zanin 2

8/23/2019 Massimiliano Zanin 2

1/19

Depression of pyrite in porphyry

co er flotation

Ian Wark Research InstituteAustralian Research Council Special Research Centre

For Particle and Material Interfaces

M. Zanin and S. Farrokhpay

Case Study


2/19

High pyrite recovery in Cu/Mo operation

4800 tphd80 = 150 m

FINAL TAIL

SCAVENGER

FINAL CON

CLEANERCOLUMNS

ROUGHERFEED

2.0 % Cp

1.6 % PyBall Mills

SIPX

grade recovery

Cp % Py % Cp % Py %

65-70 10-15 88-90 20-30

Re-grindVertical Mills

CLNR SCAV1CLNR SCAV2

Thio Lime

Case Study


3/19

Plant Evidence


4/19

Rougher Con, pH = 10.5, Eh= 250 mV SHE

Pyrite reports to the Cu concentrate even at

high pH

00

2020

4040

6060

8080

100100

1212101088664422

Flotationrecovery(%)

PyPy

Cp

Case Study

Pyrite should not float at high pH (Gaudin,1957):

Maximum pyrite recovery in the

intermediate size ranges

true flotation

pp

Xanthate adsorp. density [ ]

OH

Xlog


5/19

Possible mechanisms for pyrite recovery

Cu 2+

H O2OH

-CpCp

1. Insufficient liberation from

the copper sulphide

2. Surface Cu activation

and genuine flotation

O2

grinding

medium

pyrite

Cu-sulphide

e-

e-Fe 3+

OH-

Galvanic interactions in complex sulphideores (Huang & Grano, 2005)

yy


6/19

50

60

70

80

90

s[%]

Pyrite Liberation Data - Survey 5

Pyrite in the Rougher Con is Liberated

Pyrite is not recovered

due to mineralogical

association with

90-100%30-90%

0-30%

Ro Feed

Ro Conc

Cell 9 & 10 Conc

Ro/Scav Tail

0

10

20

30

40Ma

Liberation

QEM-Scan analysis Case Study


7/19

Time-of-Flight Secondary Ion Mass

Spectrometry: ToF-SIMS

+++

No.

ofCou

nts

Ga+ 11 kHzMass resolution ~9000

in Bunched Mode

7

m / z

Pulsed

electronflood


8/19

0.5

0.6

Pyrite +SIMSAverage with 95% confidence, N=30

Sample 1 - Rghr Con

Sample 2 - Cell 10 Con0.5

0.6

s

Pyrite -SIMSAverage with 95% confidence, N=30

Sample 1 - Rghr Con

Sample 2 - Cell 10 Con

Pyrite in the concentrate is Cu activated

Copper and collector detected on the surface of pyrite

More Si, Al, K, Ca and O on the slow-floating pyrite Case Study

Copper (+)

Fe-S

0.0

0.1

0.2

0.3

0.4

Normalisedcoun

ts

Species

0.0

0.1

0.2

0.3

0.4

Normalisedcount

Species

IBX (PA-)

Fe-S


9/19

Laboratory Work


10/19

ROCSS- + SO32- + HSO3

- + O2

ROH + 2S2O32- + CO2

X

SO32-

Py[5S0] + 5SO32- Py[S2O3

2-] + 4S2O32-

S0

Na2SO3 and DETA to depress pyrite

Reduced surface hydrophobicity

Decomposition ofxanthate

Pyrite

Cu

DETAO2

Cu (OH)2

2

CH2Cu

CH2

H2N NH

CH2 CH2}

Complexation

with Cu


11/19

FEEDO2/

Condit.SIPX DETA, Na2SO3 frother flotation

Tail

Conditioning: O2/air/no gas to control Eh and

DO level in the pulp

Flotation Baseline

Rghr Con (Plant)

Ore 1

Con 1, 2, 3, 4

0-30 mins 2 mins 2 mins 1 min

Rghr Feed (Lab grind)

+Thio primary coll.

Ore 2

Cu % Fe % Cp % Py %

Ore 1 0.66 3.4 2.0 1.6

Ore 2 0.44 4.6 1.2 9.7Feed H/G


12/19

Depression of pyrite in the rougher


13/19

60

80

100

ery[%]

60

80

100

ery[%]

Limited depression of pyrite with lime

Flotation tests on plant rougher con (60% Cp, 18% Py) (Ore 1)Pyrite is Cu and

xanthate activated

0

20

40

0 4 8 12 16 20

PyriteReco

time [min]

pH 12 with Lime

baseline (pH 10)

0

20

40

0 20 40 60 80 100

PyriteReco

Chalcopyrite Recovery [%]

pH 12 with Lime

baseline (pH 10)


14/19

60

80

100

[%]

BaselineO2

O2+DETA

O2 +Na2SO3

60

80

100

[%]

Depression of pyrite with Na2SO3 and DETA

After intense

oxygenationFlotation tests on plant rougher con (60% Cp, 18% Py) (Ore 1)

pH = 10.5 pH = 10.5

0

20

40

0 20 40 60 80 100

PyriteRecover

Chalcopyrite Recovery [%]

0

20

40

0 4 8 12 16 20

PyriteRecover

time [min]

Baseline

O2

O2+DETA

O2 +Na2SO3


15/19

Depression of pyrite in the rougher feed


16/19

80

100

[%]

Baseline

Xanth+Na2SO3+Xanth

Xanth+Na2SO3

80

100

[%]

Baseline

Xanth+Na2SO3+Xanth

Xanth+Na2SO3

No xanthate

Chalcopyrite is

not affected

Na2SO3 reduces the adsorption of xanthate

on pyrite in the feedFloat tests on rghr feed ground in the lab (1.2% Cp, 10% Py)(Ore 2)

pH = 10.5 pH = 10.5

0

20

40

0 3 6 9 12 15

PyriteRecovery

time [min]

No xanthate

0

20

40

0 20 40 60 80 100

PyriteRecovery

Chalcopyrite Recovery [%]Pyrite re-activates if

further SIPX is added

after Na2SO3


17/19

Conclusions (Case Study)

Pyrite in the feed was Cu activated, and adsorbed xanthate

even at high pH (>10.5), becoming highly floatable

Limited pyrite depression was achieved by increasing the pHwith lime

2 3

activation of pyrite in the presence of O2, reducing pyrite

recovery by 50%.

However, further addition of xanthate after depression withNa2SO3 re-activated pyrite


18/19

Conclusions (Generic)

Xanthate collectors appear not to be very selective versuspyrite

The use of sodium sulphite (Na2SO3) and similar sulphoxyspecies (Na2S2O5, Na2S2O3) or sulphur dioxide gas (SO2) may

significantly reduce/reverse xanthate adsorption on pyrite

Pyrite may re-activate down the bank if furhter xanthate isadded

For ores containing highly floatable pyrite, the use of moreselective collectors (e.g. thionocarbamates) may be preferable


19/19

Acknowledgements

The authors acknowledge the financial support of:

Australian Research Council (ARC)

Sponsors of the AMIRA International P260E project

Thank you!

massimiliano zanin 2

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