SnO2-Based Gas (Methane) Anodes for Electrowinning of Aluminum

Xiao, Saijun; Mokkelbost, Tommy; Paulsen, Ove; Ratvik, Arne Petter; Haarberg, Geir Martin

doi:10.1007/s11663-013-9889-6

Cited by 7 publications

(10 citation statements)

References 9 publications

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“…The outlet gas directly above the bath close to the anode was analysed with respect to water and hydrogen fluoride. A more detailed and schematic description of the electrochemical cell is was given by Xiao et al [11].…”

Section: Electrolysismentioning

confidence: 99%

“…Recent thermodynamical analysis and experiments have shown a depolarization of nickel based anodes using hydrogen in aluminium electrowinning [4][5][6]. Preparation of SnO 2 based inert gas anodes and their use in electrowinning of aluminium and silver has demonstrated the effect of H 2 and/or CH 4 in the anode reaction [7][8][9][10][11]. Even though there are several challenges related to e.g.…”

Section: Introductionmentioning

confidence: 99%

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A Concept for Electrowinning of Aluminium Using Depolarized Gas Anodes

et al. 2014

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Aluminium is today commercially produced by the Hall-Héroult process using consumable carbon anodes. Consumable anodes have some concerns such as CO 2 emission, continuous anodecathode distance adjustments and replacements of anodes. Replacing the consumable anodes with inert anodes has been a topic for many decades without commercial success so far. Using porous inert anodes where natural gas or hydrogen take place in the anode reaction has been shown in laboratory tests to reduce the anode potential and reduce the CO 2 emission. However, formation of water results in evolution hydrogen fluorides which must be solved. Laboratory experiments using porous depolarized SnO 2 -based anodes with CH 4 and H 2 -gases have been performed with off-gas analysis and with special attention to hydrogen fluoride evolution. Some ideas of how the additional HF evolution is presented.

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Section: Electrolysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Concept for Electrowinning of Aluminium Using Depolarized Gas Anodes

et al. 2014

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“…The theoretical cell voltage of reaction (2) is 1.1 V while for reaction (1) it is equal to 1.2 V at 1233 K (960°C) [4]. This leads to a small depolarization of the cell voltage when methane is used in such a way [4,5]. More importantly, utilizing the reducing gas, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…SnO 2 ) and graphitic porous anodes. Aluminium electrolysis experiments were carried out at 850°C in a modified electrolyte where methane and hydrogen, in separate experiments, were used as reducing gases [5,12,13]. In a recent work different graphite grades were tested as anode material and one showed better results [14].…”

Section: Introductionmentioning

confidence: 99%

“…So, we started to look at the other parameters which might play a role. Establishment of the three-phase boundary between the gas, anode and electrolyte is crucial for the accomplishment of this process [5]. In addition, it was observed earlier that cracking of the methane during the electrolysis leads to partial or even complete clogging of the anode which is detrimental for this process [6,14,15].…”

Section: Introductionmentioning

confidence: 99%

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Gas Anodes Made of Porous Graphite for Aluminium Electrowinning

et al. 2017

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One of the major downsides of the current aluminium production process is the high CO 2 emissions. One alternative to reduce this is to replace the consumable carbon anodes with inert anodes so that oxygen evolves instead of CO 2 . Also PFC emissions will be eliminated by using inert anodes. However, so far a sufficiently inert anode has not been found. Another option is to utilize natural gas through porous anodes in order to change the anode process. This will decrease CO 2 emission remarkably and also eliminate PFC emissions and anode effect. The porous anode could be made of carbon or it can be inert. However, the as-mentioned problem still exists regarding porous inert anodes. Therefore, at the moment porous carbon anodes seem to be the best practical option. In this study, porous anodes made of different grades of graphite were used for electrolysis experiments in a laboratory cell. Also, off-gas analysis was performed to get an insight of the ongoing reactions. Our results show that for some types of graphite anodes, methane participates effectively in the anodic reaction.

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