ENCYCLOPÉDIE DE LA RECHERCHE SUR L’ALUMINIUM AU QUÉBEC 2013 | Page 32

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PRODUCTION D’ALUMINIUM
ALUMINIUM PRODUCTION
UNE ÉTUDE COMPARATIVE (Une étude comparative de la caractérisation de
DE LA CARACTÉRISATION DE
SURFACE ENTRE LE COKE DE PÉTROLE ET LE MÉGOT D’ANODE RECYCLÉ mégot
surface entre le coke de pétrole et le

d’anode
A COMPARATIVE SURFACE CHARACTERIZATION STUDY recyclé)
BETWEEN PETROLEUM COKE AND RECYCLED ANODE BUTT

Arunima Sarkar1, Duygu Kocaefe1, Yasar Kocaefe1, Brigitte Morais2
1Université

2Aluminerie

du Québec à Chicoutimi, Département des sciences appliquées, 555, boul. de l’Université, Chicoutimi, Québec, Canada G7H 2B1
Alouette Inc., 400, Chemin de la Pointe-Noire, C.P. 1650, Sept-Îles, Québec, Canada, G4R 5M9

CHAIRE DE RECHERCHE UQAC/AAI SUR LE CARBONE

Methodology

Introduction
The production of primary aluminum is based on the electrolytic
smelting process using carbon anodes. Prebaked anodes
consist of about 65-68% petroleum coke, 15-25% anode butts,
and 13-15% coal tar pitch.

XPS
FT-IR

Sample C(%)

Carbon components
C=C

O(%)

C-C

CN/CO/CS

C=O

N(%) S(%) Na%

COO

Coke

Arunima Sarkar
Duygu Kocaefe
Yasar Kocaefe
Université du Québec
à Chicoutimi

Figure 2. De-convoluted C1s peaks of
(a) coke and (b) recycled anode butt

Brigitte Morais
Aluminerie Alouette Inc.

(a)

(b)

Coke

95.4

87.22

9.73

2.23

0.75

0.43

2.95

0.95

0.68

-

Butt

90

50.69

29.57

5.60

8.34

4.60

7.46

1.15

0.40

0.99

Figure 3. FTIR spectra of coke and
anode butt by DRIFT technique

SEM

Optical Microscope
(a)

FT-IR

Table 1. Atomic percentages of different components
of calcined petroleum coke and recycled anode butt

(b)

Figure 1. Comparison of the
wettability of butt and coke by
pitch

Optical
Microscope

Results

XPS
(a)

Coke and
Anode
Butts

SessileDrop Tests

Wettability of coke and anode butt particles by pitch determines
the quality of bonding between these two components and
thereby greatly affects the final anode properties such as
density, electrical resistivity, air and CO2 reactivities.
Objectives:
1. To identify the wetting mechanism of anode butts and pitch.
2. To carry out a comparative study between petroleum coke and
anode butts

Wetting Test

SEM

Table 2. Chemical composition of recycled anode
butt and petroleum coke by EDS analysis

(b)

Element

Pitch

C
O
Na

Butt
Pitch

S

Figure 4. Optical microscopy analysis of the
sessile drop interface: (a) coke-pitch (b) butt-pitch

Figure 5. SEM image analysis of (a) petroleum
coke and (b) recycled anode butt

Conclusions

1.The results show that the butt particles have a lower contact angle; consequently, they are better
wetted by pitch than the coke particles for the samples studied.
2. Optical microscopy indicate a higher penetration of pitch through the butt particles compared to
that of petroleum coke. This behavior may be the result of the presence of more oxygen containing
functional groups in the anode butt compared to the coke.
3.FT-IR analysis indicate the presence of surface functional groups on both coke and anode butt
particles which can provide chemical bonding with pitch.
4. SEM and XPS results show in butt samples the presence of Na and K due to anode’s exposure
to cryolite as well as higher concentration of oxygen-containing functional groups resulting from air
and CO2 reactivities.

Journée des étudiants – REGAL

K
Cu
Total

Recycled Anode Calcined Petroleum
Butt
Coke
Weight% Atomic% Weight% Atomic%

87.21
8.76
0.28
3.14
0.6
100

91.51
6.9
0.15
1.24
0.19
100

91.89
4.71

95.15
3.66

2.77

1.07

0.63
100

0.12
100

Acknowledgements
The technical and financial support of Aluminerie
Alouette Inc. as well as the financial support of the
Natural Scien