Electrolytes and its additives used in aluminum reduction cell: a review

Padamata, Sai Krishna; Yasinskiy, Andrey; Polyakov, P. V.

doi:10.1051/metal/2018136

Cited by 18 publications

(11 citation statements)

References 51 publications

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“…The aluminium electrolysis process is carried out at around 960 °C using NaF3-AlF3 melt but while using the KF-AlF3 melts, the process can be performed at 700-800 °C. Low-temperature melts are highly desirable as inert anodes possess low corrosion rate and thermal shocks at these conditions [13][14][15][16][17][18][19][20][21]. Nevertheless, decreasing the electrolyte temperature leads to an increase in the decomposition voltage by 0.10-0.15V.…”

Section: Introductionmentioning

confidence: 99%

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Padamata

Yasinskiy

Polyakov

2020

Transactions of Nonferrous Metals Society of China

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Inert anode development has been a topic of interest for decades. Cu-Al, Fe-Ni based alloys have shown promising results in low-temperature melts. Metallic anodes tend to contaminate the produced aluminium with their corrosion products and introducing alumina suspension particles in the electrolyte could resolve this problem by suppressing the convective transfer of corrosion products toward aluminium produced. In this paper, anodic processes on Cu-10Al electrode in molten KF-AlF3-Al2O3 (5 wt. %) and suspensions were characterized. Effects of cryolite ratio CR ( % % 3 ), temperature and particle volume fraction (φ= 0 -0.15) on the electrochemical behaviour of the anode were demonstrated. The results suggest that CR = 1.4 at 800 °C with the particle volume fraction of not more than 0.09 are better parameters for the usage of Cu-10Al anode. At melts with φ= 0.15 at all temperatures and CR values, a low current density was observed.

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Section: Introductionmentioning

confidence: 99%

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Padamata

Yasinskiy

Polyakov

2020

Transactions of Nonferrous Metals Society of China

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“…-Electrolysis temperature, a low operating temperature can reduce the corrosion rate of the anode [58];…”

Section: Factors Influencing the Performance Of The Anodementioning

confidence: 99%

An update on inert anodes for aluminium electrolysis

Yasinskiy¹,

Padamata²,

Polyakov³

et al. 2020

nfm

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This update includes the literature related to the inert anodes which were published in the past decade. The metallic anodes are widely regarded as promising candidates to replace the carbon anodes due to its attractive properties like good electrical conductivity, easy to manufacture and high resistance to high thermal shocks. The metals have been tested in pure state and alloy (binary, ternary) form. The oxide scale formed on the anode surface acts as a barrier between the electrolyte and the anode which protects the anode from being dissolved. The layer of molten fluorides is formed between the scale and the metal anode after a certain time of polarization and the oxide scale acts as a bipolar electrode. Metal like Cu is reduced at the internal side of the scale. This paper elaborates the effects of various parameters on the performance of the anode. Cu-based alloys (Cu -Ni-Fe and Cu-Al) have shown promising results and could perform well in low-temperature electrolytes. It has been well established that the Cu content in Cu-Ni-Fe and Cu-Al alloys plays a major role in the metal dissolution as the CuO/Cu2O scales formed on the outer layer act as a sacrificial one. The corrosion rate of an anode can be reduced by decreasing the operating temperature which is possible by using the KF-AlF3 melts. The use of suspensions can increase the purity of the produced metal by stopping the anode products to come in contact with cathode metal.Many industries including RUSAL and ELYSIS are still conducting a considerable amount of research to develop an inert anode and are expecting to have a carbon-free cell in the nearest future.

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“…The apparent electrical conductivity is known to be the function of the volume fraction of the dispersed phase. The Bruggeman equations describe this relationship for polydisperse particles of different irregular shapes [42]:…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

Behaviour of aluminium oxide in KF-AlF3-Al2O3 melts and suspensions

Yasinskiy

Suzdaltsev

Polyakov

et al. 2020

Ceramics International

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The article addresses the properties of melts and alumina suspensions based on the molten KF-AlF 3 -Al 2 O 3 system, the kinetics of alumina dissolution and the rheological properties that determine the sedimentation stability. The study of such suspensions has become topical due to the prospects of their use as electrolytes in the production of aluminium using carbon-free anodes. The effects of the temperature, the particle size and the phase composition of the dispersed material and its volume fraction in the suspension on the dissolution kinetics and the sedimentation velocity are studied. The experiments were carried out over the melts with cryolite ratios 1.3 and 1.5 in the range of 750-850 °C. Three different types of aluminium oxide were used. The Reynolds numbers for sedimentation have indicated the Stokesian regime. Typical alumina dissolution rates were in the range 0.028-0.167 g•kg -1 •s -1 , which is close to the values reported previously. Sedimentation velocities were in the range (0.05-3.61)•10 -2 m/s, which is several times higher than those obtained previously for 700 °C and φ = 0.24-0.32. It is shown that mechanical activation of alumina increases the performance of the suspension in terms of the sedimentation stability and the dissolution rate increasing.

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Electrolytes and its additives used in aluminum reduction cell: a review

Cited by 18 publications

References 51 publications

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

An update on inert anodes for aluminium electrolysis

Behaviour of aluminium oxide in KF-AlF3-Al2O3 melts and suspensions

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