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Compaction properties of carbon materials used for prebaked anodes inaluminum production plants
Kamran Azari a,b, Houshang Alamdari a,b,⁎, Gholamreza Aryanpour b, Donald Ziegler c,Donald Picard b, Mario Fafard b
a Department of Mining, Metallurgical and Materials Engineering, Laval University, 1065 Ave. de la Médecine, Quebec, QC, G1V 0A6, Canadab NSERC/Alcoa Industrial Research Chair MACE3 and Aluminium Research Centre – REGAL, Laval University, Quebec, QC, G1V 0A6, Canadac Alcoa Primary Metals, Alcoa Technical Center, 100 Technical Drive, Alcoa Center, PA, 15069-0001, USA
⁎ Corresponding author at: Department of MiningEngineering, Laval University, 1065 Ave. de la Médecine
The anodes used in aluminum production are formed by compaction of a paste composed of binder matrixand coarse particles of petroleum coke (aggregates). Bindermatrix composed of a coal tar pitch and fine calcinedpetroleum coke is usually characterized by coke and/or pitch content and also by the fineness of the coke parti-cles. Since the coke particles are rigid and assumed to be non-deformable during compaction, the deformationbehavior of the binder matrix plays a crucial role in the anode paste compaction process. Compaction of bindermatrix with different compositions in a rigid closed die was studied in this work. Binder matrix compositionswere compacted to a maximum uniaxial pressure of 70 MPa at 150°C. Different strain rates of 2.9 × 10−4 s−1
and 2.9 × 10−3 s−1 enabled us to evaluate the contribution of viscous behavior of thematerial to the compactionof binder matrix as a function of its composition and deformation rate. A similar experimental compactionprocedure with strain rates of 1.8 × 10−4 s−1 and 1.8 × 10−3 s−1 was applied on paste samples with differentpitch contents. This study revealed that the compaction of binder matrix and anode paste with conventionalcompositions is not significantly a time dependent process. Viscous behaviormay therefore not have a significantcontribution to the compaction of the material.
The anodes used in aluminium smelting process aremade bymixingcarbonaceousmaterials with coal tar pitch (binder) to form a pastewitha doughy consistency. This material is most often vibro-compacted butin some plants pressed during which it is deformed and densified. Thegreen anode is then sintered to increase its strength through decompo-sition and carbonization of the binder. Green density of anode dependson the compaction behavior of the paste and strongly correlates withfinal density, electrical [1] and mechanical [2] properties of the anode.The main target of anode makers is therefore to obtain high and homo-geneous density through the anode in order to decrease its electricalresistivity and to increase its service life. This work was performed tostudy the compaction behavior of anode paste and to reveal the effectof its rheological behavior on its compaction during forming.
Two size ranges of coke are normally used tomake anode paste: largeaggregates (N0.15 mm and b9.5 mm) and fine particles (b0.15 mm),also called fine coke. During mixing, fine cokes are embedded into theliquid pitch resulting in a viscous material, which surrounds the largecoke aggregates. This viscous material, also called binder matrix, acts tobond the aggregates together. It also deforms during compaction and
, Metallurgical and Materials, Quebec, QC, G1V 0A6, Canada.
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fills the voids either between the large aggregates or inside them. Thecoke aggregate particles are considered as a non-deformable phase ofthe paste but being subjected to rearrangement during compaction.Coke aggregates and binder matrix are therefore the principal constitu-ents of anode paste, which may influence its compaction properties,and consequently the green density obtained after compaction.
Since the binder matrix surrounds the coarse coke particles anddeforms during compaction, its rheological parameters could be im-portant in determining compaction behavior of paste. In turn, volumefraction and granulometry of fine coke could be considered as twomajor parameters affecting the rheological properties of the bindermatrix and its capability in filling the voids. The research works onprebaked anode paste have been mostly focused on the effect of finecoke granulometry on the pore filling capability of binder matrix andon the properties of the final product. Hulse [3] reported that prebakedanode paste has a granulo-viscoelastic behaviorwhich depends on tem-perature, pitch content and coke particle characteristics such as size dis-tribution, shape and roughness. By increasing the pitch content andtemperature the viscosity of paste decreases and viscosity has a largercontribution in the compaction. Higher coke content and coke finenesson the other hand enhance the elastic behavior. Figueiredo [4] showedthat by using smaller particle size of the fine coke and optimizing thepitch content a larger density and lower electrical resistivity and air per-meability can be obtained. Similar improvement was reported on the
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baked properties of bindermatrix only, when theweight fraction of finecoke particles smaller than 96 μm was increased from 43% to 86% andoptimum pitch content was used [5]. It has also been reported thatthe granulometry and the amount of fine coke influence the capabilityof the binder matrix in filling the voids between coke aggregates.Vidvei [6] found out that decreasing the particle size of the finecoke (60% smaller than 75 μm) led to an improvement in anode densityand a decrease in electrical resistivity. However, behavior of paste duringcompaction was not reported in the literature.
Rheological properties of binder matrix have been extensively in-vestigated for Soderberg anodes where the anode is not pre-formedbut baked in-situ over the electrolysis cell. Gildebrandt et al. [7,8],Kravtsova et al. [9] and Vershinina [10] studied the effect of coke con-tent, temperature, and particle size of fine coke on viscosity of bindermatrix. Their experimental data showed that the viscosity of bindermatrix decreases with increasing temperature and particle size offine coke but it increases significantly when the amount of fine coke(b74 μm) exceeds over 50 wt% of binder matrix. The possible explana-tion for the effect of particle size on viscosity has been given byHulse [3]and Kravtsova [9] who ascribed this effect to direct particle-particle in-teraction, number of contacts and thickness of pitch layer on the particlesurface. Sakai [11,12] found that 50 wt% of fine coke in binder matrix isa critical point since its behavior changes from Newtonian to viscoelas-tic when coke amount exceeds this point. Again, the influence of bindermatrix formulation on compaction behavior of paste and green densityof anode has not been considered in these works since they have beenmostly carried out on Soderberg anodes where the compaction ofpaste is not of great interest. There is thus a lack of information onthe effect of binder matrix parameters on anode paste compactionbehavior.
Anode forming process takes place within a relatively short periodof time, typically one minute for vibro-forming and half a minute forpressing. Considering the viscous properties of binder matrix, at a firstglance, onemay expect that the compaction rate plays a significant rolein paste compaction behavior. Strictly speaking, it is expected that thepaste shows a time dependent behavior and the viscous phase, i.e. bind-er matrix, flows under pressure and fills the voids over time leading to abetter densification at longer pressing times. On the other hand, at highcoke volume fractions, a solid skeleton may form and the compactionbehavior may be governed by the strength of the particle/particle con-tacts. This study aimed thus to reveal whether the binder matrix andpaste exhibit a time-dependent behavior andwhether this time depen-dency affects the compaction behavior of anode paste. However, inaddition to rheological behavior, other phenomena such as air entrap-ment may affect the time dependency and compaction behavior of thematerial that can be studied in future works. In a first step, the compac-tion characteristics of binder matrix as a function of weight fractionand particle size of fine coke were studied. Then the compaction testswere performed on paste with different pitch contents and fine cokegranulometries to better understand the viscous behavior and itsimportance in the compaction of paste with different formulations.
2. Materials and methods
A commercially available calcined petroleumcokewith a real densityof 2.057 g/cm3 was milled in a laboratory ball mill to produce fine
Table 1Ball milling parameters, size distribution and specific surface area of the fine cokes.
coke. Different milling times were used to obtain three differentgranulometries. Size distribution and Blaine number (BN) of thefine fractions were measured by sieve analysis and laser diffractionparticle size analyzer (Malvern Mastersizer 2000), respectively.Blaine number is an indication of specific surface area (SSA) and isused to assess the fineness of the powder. Specific surface area of thefine cokes was measured using BET method (Micromeritics, TriStar II).Table 1 presents the milling parameters, particle size distribution andspecific surface area of the prepared fine cokes.
Each fine coke with a given Blaine number was mixed with a coaltar pitch at different pitch to fine coke ratios (P/FC), indicated in Table 2,to produce a binder matrix. The pitch had a Mettler softening point of109 °C and a quinoline insoluble (QI) content of 15.5%. Lower P/FCratios were used for the samples with a Blaine number of 2300 sincethis Blaine number represents lower specific surface area to absorbthe pitch. Fine coke and pitch were preheated at 178°C and mixed at178°C for 10 minutes in a Hobart N50 mixer, installed in an oven. Thetotal mass of fine coke and pitch was 274 g for all formulations.
The binder matrix compositions were compacted in a cylindricalsteel mold with an inner diameter of 63 mm. The height of the sampleswasmeasured after putting the punch on the sample before compactionand the bulk density of each composition was calculated. Compactiontests were carried out at two constant displacement rates (DR) of 1and 10 mm/min. Average deformation rates were calculated using theinitial and final heights of the samples (Table 2). Uniaxial pressure wasprogressively increased to 70 MPa. The tests were performed at 150°Cinside a three zone split-tube furnacemounted on aMTS Servohydraulicpress. Force-displacement data were obtained from themachine using a250 KN MTS load cell and a 150 mm position transducer (LVDT) of thepress. Mass, diameter and height of the samples were measured andused to plot the compaction curves. Having the real time height of thesample inside the mold, geometrical density was calculated at eachpoint of the force-displacement curve. Evolution of the relative densitywas then plotted as a function of applied pressure. Relative density isthe ratio of geometrical density to the real (theoretical) density of thematerial. Real density of coke and pitch were used to calculate the realdensity of pitch/coke compositions. Each sample was repeated twice toensure the repeatability of the test. The tests were repeatable thus theresults of one test for each sample were used in this work.
For the second part of the tests, the influence of displacement rateon the compaction of anode pastes (including large aggregates)with dif-ferent compositions was studied. Table 3 shows the size distribution ofcoke particles used to prepare the samples. Table 4 summarizes the for-mulations of paste samples and the compaction parameters used foreach sample. Our preliminary experiments showed thatwhen the Blainenumber of the fine coke is 4000 the optimum pitch to coke ratio (P/C) is16.2/100. This P/C ratio results in a maximum baked density of anode.Total mass of coke and pitch was 488 g for all compositions. The pastesamples were made with the same mixing parameters as used to pre-pare the binder matrix. They were then compacted at 150°C to a maxi-mum pressure of 60 MPa at different displacement rates of 0.1, 1 and10 mm/min. Average strain rates are shown in Table 4. Two replicatesof each sample were prepared to verify the test repeatability.
For further investigation of the viscous behavior of the paste duringcompaction, a creep testwas performed on the paste samples. The pastesamples were first compacted with a displacement rate of 10 mm/min
Particle size distribution (wt%) BET surface area (m2/g)
⁎ Creep test on the paste at 150°C and 10 MPa for 1 h.
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until an axial pressure of 10 MPa was reached. Then, the pressurewas kept constant at 10 MPa for 1 h while displacement was beingrecorded. Densification of the paste at constant pressure was used tostudy the influence of time and thus viscous behavior.
3. Results and discussion
3.1. Binder matrix
Fig. 1 shows the effect of P/FC ratio and displacement rate (DR) onthe compaction curves of the binder matrix samples when a fine cokewith a SSA of 2.9 m2/g is used. For each sample, two displacementrates were used; 1 and 10 mm/min. As expected, it can be seen thatP/FC ratio has a significant effect on the compaction behavior of thematerial. The slope of the curves at early stages of compaction in-creases drastically when P/FC ratio increases. This is due to this factthat movement and rearrangement of particles happen at the earlyphase of compaction [13] since the material is not close packedafter filling the die. Pitch is assumed to act as a lubricant to help par-ticle rearrangement. Therefore, the samples with higher P/FC ratiosreached a higher relative density at lower pressure and revealed asteeper slope. Displacement rate, on the other hand, has a minorinfluence on the compaction curves. At low P/FC ratio, i.e. 30/100,displacement rate did not influence the compaction behavior andthe curves coincided. The effect of DR became more distinctive as theP/FC ratio increased and resulted in a material with lower viscosity.This is the characteristic of viscoelastic materials for which the compac-tion time contributes to densification [14].
For the compositions with the SSA of 4.1 and 6.1 m2/g the effect ofP/FC on the compaction curves showed the same trend (Figs. 2 and 3)with the exception that the strain rate dependency shifted towardhigher P/FC as the Blaine number increased. For both numbers, com-positions with a P/FC ratio of 34/100 did not reveal a viscous behaviorduring compaction, since the curves of differentDRs practically coincided.For the compositions with the P/FC ratios of 38/100 and 42/100 a non-negligible difference was observed when different DRs were used andlower DRs resulted in better densification. This indicates that bindermatrix samples with the SSA of 4.1 and 6.1 m2/g, start to reveal a viscousbehavior when P/FC ratios exceeds 38/100.
For a given granulometry for fine coke (BN), the influence of strainrate on compaction behavior of binder matrix was less significant forlower P/FC ratios. For a specific size distribution of particles, whensolid concentration increases, particle-particle interaction becomes adominant mechanism that restricts movement of particles and masks
Table 3Size distribution of coke particles in the paste samples.
Size range (US mesh) −4 + 8 −8 + 16 −16 + 30
Wt% 22.0 10.0 11.5
viscous effect of the pitch. In other words, the viscosity of binder matrixincreases with increasing the content of fine coke [3,7,8], and subse-quently, the contribution of compaction time is decreased.
According to Figs. 1–3, for a given granulometry of fine coke, compo-sitionswith higher P/FC ratio required lower pressure to reach a specificrelative density. The reason lies in the fact that changing the proportionof material constituents, i.e. pitch and coke contents, not only changesthe whole material properties such as viscosity and yielding character-istics [7–10] but also varies some structural aspects. For example pitchwets the coke particles and acts as a lubricant. A high P/FC ratio, there-fore, provides a continuous layer of pitch on the particle surface, whichreduces the interparticle friction and facilitates the rearrangement ofthe particles that contribute to compaction. In addition, it was observedthat as the pitch content is higher in binder matrix, the compactioncurve begins from a higher initial relative density, as indicated inTable 5. This is basically due to the fact that the initial density wasrecorded after applying a small pre-load of 14.2 kPa. As stated above,the slope of the compaction curves increases with increasing the P/FCratio and is considerably high at very early stages of the compactionprocess. Consequently, the samples with higher P/FC ratio are muchmore sensitive to pre-load than are those with lower P/FC ratios. Thisexplains the difference between the initial densities of different samples.
In order to evidence the effect of particle size distribution, somecompaction curves are presented for the same P/FC ratios while vary-ing the fine granulometry (Figs. 4 and 5). Again, it can be seen thatgranulometry (BN) has a significant effect on the compaction behaviorof thematerial. Similar to the effect of P/FC ratio, the slope of the curvesat early stages of compaction increases drastically when BN decreases.In addition, displacement rate has a negligible influence on the compac-tion curves.
For a given P/FC ratio, compositions with larger granulometryneeded lower pressure to reach a specific relative density. For largeparticles, the specific surface area decreases and less pitch is requiredto wet the particle surface. Therefore, more pitch is available to fill thevoids and to lubricate the particle/particle interfaces facilitating theirmovement. For example for the P/FC ratio of 38/100 when the SSA offine coke was reduced from 6.1 to 2.9 m2/g, the specific amount ofpitch (pitch volume per unit of coke surface) increased from 0.048to 0.1 cm3/m2, as shown in Table 6. Another parameter, which mayaffect the compaction behavior, is the strength of the particle bed.Strength of a powder structure, as expressed in Eq. (1), depends on
Fig. 1. Compaction curves for the binder matrix samples made from a fine coke withSSA of 2.9 m2/g (BN 2300) and P/FC ratios of 30/100, 34/100 and 38/100.
Fig. 3. Compaction curves for the binder matrix samples made from a fine coke withSSA of 6.1 m2/g (BN 6300) and P/FC ratios of 34/100, 38/100 and 42/100.
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the number of contacts between the particles and the strength of a con-tact [9]. Strength of a contact is proportional to particle radius andhas aninverse relationship with the square of inter-particle distance (Eq. (2)).For a constant volume fraction of pitch, increasing the particle size hastherefore two consequences; to decrease the number of contacts andto thicken the pitch layer over the particles. Consequently, by increasingthe particle size the strength of the structure is reduced and therefore, alower pressure is required for the compaction.
S ¼ m:Sc ð1Þ
Scer=h2 ð2Þ
S strength of the powder structurem number of contacts per unit volume of materialSc strength of a contactr particle radiush thickness of pitch layer (particle distance)
The influence of deformation rate on the compaction of bindermatrixis negligible and is not significantly affected by P/FC ratio or particle size
Fig. 2. Compaction curves for the binder matrix samples made from a fine coke withSSA of 4.1 m2/g (BN 4000) and P/FC ratios of 34/100, 38/100 and 42/100.
distribution. The only exception is the composition with SSA of 2.9 m2/gand P/FC ratio of 38/100 for which the pitch content is more than theoptimum ratio of 35/100 reported by Smith [5]. This suggests that thedensification of the binder matrix, in the composition range of thisstudy, depends basically on the applied pressure and the compactiontime may not have a significant contribution to its compaction behavior.
3.2. Anode paste
The same experiments were conducted to record the compactionbehavior of anode pastes, comprising binder matrix and large cokeaggregates. The granulometry of large coke was chosen according toTable 3 and two Blaine numbers of 4000 and 6300 were chosen forthe fine fraction of coke. The total pitch to coke (P/C) ratios of 16.2/100,19/100 and 22/100 were used to make the samples. The compactioncurves using two displacement rates of 1 and 10 mm/min are presentedin Figs. 6 and 7.
For a given pitch quantity, decreasing the displacement rate from10 mm/min to 1 mm/min did not result in a better densification.Comparing Figs. 6 and 7 reveals that the Blaine number of fine coke,in the range of these experiments, does not change the compactionbehavior of the anode paste. The P/C ratio, however, showed a consider-able effect on densification of anode paste, with higher P/C resulting in asteeper slope of the curves and higher final density. The possible reasonswere explained in section 3.1.
Some compaction curves are presented in Figs. 8 and 9 to showthe influence of particle size distribution (BN) and SSA of fine cokefor the same P/C ratio. It can be seen that the effect of particle size dis-tribution of fine coke on the compaction behavior of the material isnot evident. Higher BN of fine coke slightly increases the final density.
Table 5Initial apparent and relative densities of binder matrix with different compositions beforecompaction.
Fig. 4. Compaction curves for the bindermatrix samples madewith a P/FC ratio of 34/100and fine cokes with SSA of 2.9, 4.1 and 6.1 m2/g (BN 2300, 4000 and 6300, respectively).
Fig. 5. Compaction curves for the bindermatrix samples madewith a P/FC ratio of 38/100and fine cokes with SSA of 2.9, 4.1 and 6.1 m2/g (BN 2300, 4000 and 6300, respectively).
Fig. 7. Compaction curves for the paste samples made from a fine coke with SSA of6.1 m2/g (BN 6300) and P/C ratios of 16.2/100, 19/100 and 22/100.
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An extremely low displacement rate of 0.1 mm/min was also ap-plied for two samples. As shown in Figs. 10 and 11, this lowdeformationrate resulted in a slight improvement of compacted density. This im-provement, although negligible, was the motivation to investigate thecompaction behavior and to reveal whether the anode paste continuestoflowunder a constant pressure. Densification of the anode pasteswasperformed under a constant pressure of 10 MPa (confined creep tests).The results are presented in Figs. 10 and 11 where the vertical linesshow the densification under constant pressure during 1 h. Densifica-tion at constant pressure is also plotted as a function of time in Fig. 12.It can be seen that the densification occurs essentially during the first2 minutes and then the curves flatten. After 1 h of creep test the maxi-mum increase in relative density was 0.019.
The results presented in Figs. 10 and 11 suggest that the pasteflows under a constant pressure. However the deformation derivedfrom this flow is negligible compared to that from instantaneous
Table 6Specific pitch content for binder matrix compositions.
deformation. Time dependency of compaction behavior did notchange even with increasing the P/C ratio to more than its optimumvalue (16.2/100). In the industry an optimum P/C ratio of 13/100–15/100 is used to obtain a maximum baked apparent density. Consid-ering the fact that deformation rates in an industrial compactionprocess is roughly ten times higher than the maximum rate chosenin this study, deformation rate dependency could be observed in anindustrial case. For example, compaction time may not be enough toallow particle rearrangement. It is also possible that air entrapmentoccur and influence the final density.
3.3. Influence of Blaine number vs. pitch ratio
It is worthwhile to evaluate which parameter among those variedin this study was more effective on the compaction of binder matrix
Fig. 8. Compaction curves for the paste samples made with a P/C ratio of 16.2/100 andfine cokes with SSA of 4.1 and 6.1 m2/g (BN 4000 and 6300, respectively).
Fig. 10. Compaction curves for the paste samples made from a fine coke with SSA of4.1 m2/g (BN 4000) and P/C ratios of 16.2/100 and 22/100.
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and anode paste. The influence of pitch content and Blaine number(SSA) of fine coke on the final relative density of binder matrix andpaste is summarized in Table 7. It should be stated that these relativedensities were calculated using the geometrical density of the sam-ples when they were taken out of the mold and expansion hadoccurred. The data is presented for the two replicates to show theprecision of the measurements. When the composition is changed anew material with different intrinsic characteristics is formed whichaffects the compaction process. At a constant P/FC ratio, decreasingthe particle size of fine coke resulted in lower relative density ofbinder matrix since the increased surface area led to under-pitching.Similar results have been reported in the literature for the greenapparent density of compacted binder matrix with changing the BNfrom 1220 to 6550 [5]. An increase in the relative density of bindermatrix was observed with changing the P/FC ratio from 34/100 to38/100. This influence of P/FC ratio was more evident with increasingthe SSA where the largest improvement in the relative density (1.9%)was observed for the sample with a SSA of 6.1 m2/g (Table 7). Whenthe P/FC ratio was increased from 34/100 to 38/100 the binder matrixwith a SSA 6.1 m2/g presented the lowest increase in the specificpitch content (0.005) (Table 6). This reveals that binder matrix com-positions with higher Blaine number (dry samples) are more sensi-tive to pitch content that is in agreement with the literature [15]. Inaddition, this is the influence of fineness of fine coke that leads to
Fig. 9. Compaction curves for the paste samples made with a P/C ratio of 19/100 andfine cokes with SSA of 4.1 and 6.1 m2/g (BN 4000 and 6300, respectively).
higher relative density. While using an optimum amount of pitch,increasing the fineness of fine coke can contribute to improving therelative density of binder matrix.
For anode pastes with a constant P/C ratio (Table 7), using finerparticles (BN 6300) did not result in a meaningful change in relativedensity. This is in agreement with a previous work [6] where higherBN resulted in an insignificant increase in the green apparent densityof compacted paste. However, it has been reported that it may im-prove the baked apparent density and thus the anode properties [6].The better anode properties were explained by improved void fillingeffect of finer particles. When the BN of fine coke is increased, aconsiderable improvement in the green density can be achieved ifunder-pitching is avoided by using higher pitch content [4]. Table 7shows clearly that for the range of parameters studied in this work,the effect of pitch content on the relative density of anode samplesis more significant than that of the fineness of the fine fraction.
4. Conclusion
The uniaxial compaction characteristics of binder matrix andanode paste revealed useful information about their behavior duringdensification. It has been shown that the displacement rate has littleeffect on the achieved density of both binder matrix and anode paste.
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Creep (time-dependent component of densification) contributes to lessthan 2% of the relative density. Pitch-to-coke ratio was found to be themost important parameter determining the compaction behavior ofthemixtures. Coarser coke particles in the binder matrix (lower SSA) re-sult in its better densification. This unexpected behavior is attributed tothe specific pitch content, which decreases by increasing the specific sur-face area of the coke with higher Blaine numbers. At a constant pitchratio, the effect of BN on densification of the anode paste is, however,mitigated.
Acknowledgement
Authors would like to acknowledge the financial support of NSERCand Alcoa. A part of the research presented in this paper was financedby the Fonds de Recherche du Québéc-Nature et Technologies (FRQ-NT)by the intermediary of the Aluminium Research Centre – REGAL. Thetechnical assistance of Hugues Ferland at Laval University is gratefullyacknowledged.
References
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[2] M. Paz, J.R. Boero, F. Milani, Coke density and anode quality, TMS Annual Meeting;1993, Minerals, Metals & Materials Society, Denver, CO, USA, 1993, pp. 549–553.
[4] F.E.O. Figueiredo, C.R. Kato, A.S. Nascimento, A.O.F. Marques, P. Miotto, Finer Finesin Anode Formulation, TMS Annual Meeting; 2005, Minerals, Metals and MaterialsSociety, San Francisco, CA, United States, 2005, pp. 665–668.
[5] M.A. Smith, An Evaluation of the Binder Matrix in Prebaked Carbon Anodes Usedfor Aluminium Production, University of Auckland, 1991.
[6] T. Vidvei, T. Eidet, M. Sorlie, Paste Granulometry and Soderberg Anode Properties,TMS Annual Meeting; 2003, Minerals, Metals and Materials Society, San Diego,CA, United States, 2003, pp. 569–574.
[7] E.M. Gil’debrandt, V.K. Frizorger, E.P. Vershinina, The effect of the granulometriccomposition and content of a coke charge on the viscosity of pitch-coke com-pounds, Russian Journal of Non-Ferrous Metals 50 (1) (2009) 30–32.
[8] E.M. Gildebrandt, V.K. Frizorger, E.P. Vershinina, E.D. Kravtsova, The viscosity ofpitches and coke pitch compositions, Russian Journal of Non-Ferrous Metals 49(6) (Dec 2008) 456–458.
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Kamran Azari Received his MSc degree inMaterials Scienceand Engineering in 2001 from Isfahan University of Tech-nology, Iran. He worked at Naghsh Jahan Steel ResearchInstitute, Iran on the optimization of steelmaking pro-cesses to improve steel cleanliness. In 2008, he pursuedhis academic formation. He is currently a PhD student atthe Department of Mining, Metallurgical and MaterialsEngineering, Université Laval, Canada. His research pro-ject is on the carbonaceous raw materials and formationof prebaked anodes used in Aluminium production, incollaboration with Aluminium Research Centre-REGALand Alcoa Canada.
Dr. Houshang Alamdari received MSc degree in 1996 andPhDdegree in 2000 fromUniversité Laval, Canada. He pursuedhis research activities at Hydro-Québec research institute,Canada on synthesis of nanocrystallinematerials for hydrogenstorage. He held the process director position at Nanox Inc,Canada and was involved in development and scale up of aproduction process for nanostructured perovskite-type mate-rials for automotive catalysts. In 2006, he joined Laval Univer-sity as professor at De partment of Mining, Metallurgy andmaterials Engineering, Université Laval, Canada. He is current-ly director of Regal-Laval research center where his researchactivities are focused on aluminium production process.
Dr. Gholamreza Aryanpour, earnedhis PhD fromUniversiteGrenoble I, France in 1999. He has been an assistant professorin Isfahan University of Technology from 1999 to 2009. Since2009 he has been working in the Universite du Quebec aChicoutimi and then in Universite Laval as a professional re-searcher. His research interests are in the fields of metallurgyand mechanics of materials.
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Dr. Donald Ziegler is Program Manager for Modeling ofAlcoa PrimaryMetals. Having completed his Ph.D at the Uni-versity of California, Berkeley and a post-doc atMADYLAM inGrenoble, he has been with Alcoa for 27 years. His researchinterests were initially in modeling of MHD phenomena inHall cells, but he is increasingly involved in modeling appli-cations in Hall cell structures and anode forming.
Dr. Donald Picard graduated from Université Laval in Me-chanical Engineering and completed his PhD in 2007 in thefield of carbon materials characterisation. He has developedan expertise in the field of thermomechanical characterisa-tion of carbon materials and in modelling of viscoelasticconstitutive laws. He is actually a professional researcher atUniversité Laval and he is mainly involved in one IndustrialResearch Chair and one Collaborative Research and Develop-ment projects financed by the Natural Sciences and Engi-neering Research Council of Canada (NSERC) and AlcoaCanada.
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Dr. Mario Fafard is a Professor at Université Laval since1987. He is the holder of theNSERC/Alcoa Industrial ResearchChair, at the Civil and Water Engineering Department. Hismain research interests are in the areas of advanced numeri-cal modeling of aluminium cell, and thermomechanical test-ing on refractory materials at high temperature.
