Air and CO2 Reactivity of Carbon Anode and Its Constituents: An Attempt to Understand Dusting Phenomenon

Chevarin, F.; Lemieux, L.; Ziegler, Donald; Fafard, Mario; Alamdari, Houshang

doi:10.1007/978-3-319-48248-4_192

Cited by 10 publications

(12 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chevarin et al [14] showed that when a pitch sample is baked alone (without the presence of coke), the surface area of its micropores (0.0004-0.0014 lm in size, measured by CO 2 adsorption with Dubinin-Radushkevitch at 0°C equation) is the same as that of the baked coke, being around 2.4 m 2 /g. When a totally covered sample is baked, the thickness of the pitch layer is high enough to be considered as a pitch being baked alone, resulting in the same surface of the pores.…”

Section: Characterization Of Anode and Coke/pitch Mixturesmentioning

confidence: 97%

“…The manufacturing procedure of anode samples was detailed in Chevarin et al [14,18] and Azari et al [19,20]. The chemical compositions of the calcined coke and coal tar pitch before baking were determined by X-ray Fluorescence (XRF) with the ASTM D4326-06 standard test method and are detailed in Table 1.…”

Section: Preparation Of Covered Coke Particlesmentioning

confidence: 99%

“…Some authors associate the anode consumption with the possible selectivity of CO 2 molecules to pitch [8][9][10][11] or binder matrix constituents [6,12,13]. To validate the CO 2 selectivity, Chevarin et al [14] prepared anode constituents (coke, pitch and butt) with a particle size of À1.4 + 1.0 mm [15] and compared their reactivity with thermo-gravimetric analysis at 960°C under CO 2 atmosphere. They remarked that for this sample size, the specific surface area of anode, measured with BET model under N 2 atmosphere at À196°C, did not follow the classical rule of mixture with specific surface areas of coke, butt and pitch.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Substrate effect of coke particles on the structure and reactivity of coke/pitch mixtures in carbon anodes

Chevarin

Azari²,

Ziegler

et al. 2016

Fuel

Self Cite

View full text Add to dashboard Cite

Section: Characterization Of Anode and Coke/pitch Mixturesmentioning

confidence: 97%

Section: Preparation Of Covered Coke Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Substrate effect of coke particles on the structure and reactivity of coke/pitch mixtures in carbon anodes

Chevarin

Azari²,

Ziegler

et al. 2016

Fuel

Self Cite

View full text Add to dashboard Cite

“…A quartz crucible was used for all thermo-gravimetric (TG) measurements. 50 to 300 mg of anode particles (corresponding to 1 to 3 particles) were gasified under air atmosphere [38,39]. Five gasification tests were performed and the reaction rate was determined using Equation (3)…”

Section: Air Reactivity Testsmentioning

confidence: 99%

Evolution of Anode Porosity under Air Oxidation: The Unveiling of the Active Pore Size

Chevarin

Ishak

Ziegler

et al. 2017

Metals

View full text Add to dashboard Cite

Abstract:The carbon anode, used in aluminum electrolysis (Hall-Héroult process), is over-consumed by air oxidation and carboxy-reaction (with CO 2 ). Several anode features may affect this over-consumption, such as impurity content, graphitization level and anode porosity features (e.g., porosity volume fraction or pore size distribution). The two first parameters are basically related to the quality of raw materials and coke calcination conditions. Anode porosity is, however, greatly affected by anode manufacturing conditions, and is possible to be modified, to some extent, by adjusting the anode recipe and the processing parameters. This work aims to investigate the effect of anode porosity on its air reactivity. Baked anode samples were prepared in laboratory scale and then crushed into powder form (−4760 + 4000 µm). The recipe for anode preparation was similar to a typical industrial recipe, except that in the lab scale no butt particles were used in the recipe. Anode particles were then gasified at six different conversion levels (0, 5, 15, 25, 35 and 50 wt %) under air at 525 • C. The porosity was characterized in several pore size ranges, measured by nitrogen adsorption and mercury intrusion (0.0014-0.020, 0.002-0.025, 0.025-0.100, 0.1-40.0 and superior at 40 µm). The volume variation of each pore range, as a function of carbon conversion, was assessed and used to determine the size of the most active pores for air oxidation. The most active pore size was found to be the pores inferior at 40 µm before 15 wt % of gasification and pores superior at 40 µm between 15 and 50 wt % of carbon conversion. Limitation of pore size range could be used as an additional guideline, along with other targets such as high homogeneity and density, to set the optimum anode manufacturing parameters.

show abstract

“…The carbon anodes are used to provide carbon for the chemical reaction, as well as the electrical current necessary for the electrolysis. To ensure the proper functioning of the electrolysis cells, carbon anodes are subject to quality controls such as chemical reactivity [3,4] or mechanical properties such as strength [5] or density [6] during their production. The quality control is performed on core samples, and usually extracted from the top of the anodes beside the stub holes.…”

Section: Introductionmentioning

confidence: 99%

Electrical Resistivity Measurement of Carbon Anodes Using the Van der Pauw Method

Rouget

Chaouki

Picard

et al. 2017

Metals

View full text Add to dashboard Cite

Abstract:The electrical resistivity of carbon anodes is an important parameter in the overall efficiency of the aluminum smelting process. The aim of this work is to explore the Van der Pauw (VdP) method as an alternative technique to the standard method, which is commonly used in the aluminum industry, in order to characterize the electrical resistivity of carbon anodes and to assess the accuracy of the method. For this purpose, a cylindrical core is extracted from the top of the anodes. The electrical resistivity of the core samples is measured according to the ISO 11713 standard method. This method consists of applying a 1 A current along the revolution axis of the sample, and then measuring the voltage drop on its side, along the same direction. Theoretically, this technique appears to be satisfying, but cracks in the sample that are generated either during the anode production or while coring the sample may induce high variations in the measured signal. The VdP method, as presented in 1958 by L.J. Van der Pauw, enables the electrical resistivity of any plain sample with an arbitrary shape and low thickness to be measured, even in the presence of cracks. In this work, measurements were performed using both the standard method and the Van der Pauw method, on both flawless and cracked samples. Results provided by the VdP method appeared to be more reliable and repeatable. Furthermore, numerical simulations using the finite element method (FEM) were performed in order to assess the effect of the presence of cracks and their thicknesses on the accuracy of the VdP method.

show abstract

Air and CO2 Reactivity of Carbon Anode and Its Constituents: An Attempt to Understand Dusting Phenomenon

Cited by 10 publications

References 9 publications

Substrate effect of coke particles on the structure and reactivity of coke/pitch mixtures in carbon anodes

Substrate effect of coke particles on the structure and reactivity of coke/pitch mixtures in carbon anodes

Evolution of Anode Porosity under Air Oxidation: The Unveiling of the Active Pore Size

Electrical Resistivity Measurement of Carbon Anodes Using the Van der Pauw Method

Contact Info

Product

Resources

About