Abstract
Contact resistance between cathode block and cast iron plays an important role for the ohmic resistance of the cathode system and hence for the cathode voltage drop (CVD). Investigations of the standard dove-tail cathode slot design showed poor electrical contact in the bottom of the slot and small contact area on the cathode wings. Different thermo-mechanical properties of carbon cathode block, cast iron, and steel collector bar resulted in displacements relative to each other after rodding, during cooling and handling. To mitigate this effect without changing materials or procedures, different slot geometries were modeled with respect to preheating and casting. By introducing anchoring grooves for the cast iron at the bottom corners of the slot, bottom contact was achieved: Lab tests proved that voltage drop between cathode slot bottom and cast iron decreased significantly. Subsequent field trials showed a CVD reduction of 20 mV.
References
M. Segatz et al., Hydro’s cell technology path towards specific energy consumption below 12 kWh/kg. Light Met., 301–305 (2016)
P. Thibeault et al., Rio Tinto Alcan AP4X low energy cell development. Light Met., 543–547 (2013)
A. Zarouni, M. Reverdy, Dubal low energy aluminium electrolysis cell design and operation. ALUM., No. 1–2, 26–27 (2014)
D. Zhou et al., Chinalco 600 kA high capacity low energy consumption reduction cell development. Light Met., 483–487 (2015)
D. Lu et al., New progress on application of NEUI 400 kA family high energy efficiency aluminum reduction pot (“HEEP”) technology. Light Met., 443–448 (2011)
J.T. Keniry, Threats & opportunities for aluminium smelting in a carbon-priced world. in Proceedings of the 10th Australasian Aluminium Smelting Technology Conference, Lanceston, Australia, October 2011
V. Kovács, L. Kiss, Comparative analysis of the environmental impacts of aluminum smelting technologies. Light Met., 529–534 (2015)
W.E. Haupin, Cathode voltage loss in aluminum smelting cells. Light Met., 339–349 (1975)
M. Sørlie, H. Gran, Cathode collector bar-to-carbon contact resistance. Light Met., 780–787 (1992)
F. Hiltmann et al., Influence of temperature and contact pressure between cast iron and cathode carbon on contact resistance. Light Met., 277–283 (1996)
R. Beeler, Bar to block contact resistance in aluminum reduction cell cathode assemblies. Light Met., 507–511 (2014)
M. Dupuis, Development and application of an ANSYS Based thermo-electro-mechanical collector bar slot design tool. Light Met., 519–524 (2011)
M. Emami et al., Development of a new methodology to measure contact pressure along a thermo-electro-mechanical interface. Light Met., 1281–1284 (2014)
D. Richard et al., Thermo-electro-mechanical modeling of the contact between steel and carbon cylinders using the finite element method. Light Met., 523–528 (2000)
D. Richard et al., Challenges in Stub hole optimisation of cast iron rodded anodes. Light Met., 1067–1072 (2009)
A.T. Brimmo, M.I. Hassan, Modeling the electrical contact at steel-carbon interfaces. JOM 68(1), 49–57 (2016)
I. Letizia et al., How to improve the pig iron sealing of metallic bars in cathode carbon blocks. Light Met., 1025–1036 (1985)
B. Larsen, M. Sørlie, Stress analysis of cathode bottom blocks. Light Met., 641–646 (1989)
L. Caruso et al., Experimental comparison of cathode rodding practices. Light Met., 827–831 (2007)
S. Wilkening, J. Côté, Problems of the stub-anode connection. Light Met., 865–873 (2007)
M. Sørlie, H.A. Øye, Cathodes in aluminium electrolysis (Aluminium-Verlag Marketing & Kommunikation GmbH, Düsseldorf, 2010)
M. Sørlie et al., Early failure mechanisms in aluminium cell cathodes. Light Met., 299–308 (1993)
A. Zolochevsky, Rapoport-samoilenko test for cathode carbon materials—II. Swelling with external pressure and effect of creep. Carbon 43, 1222–1230 (2005)
E. Bernhauser, J. Mittag, A comparative examination on ageing of cathodes amorphous versus graphitic type. Light Met., 725–729 (1994)
J. Hop et al., Chemical and physical changes of cathode carbon by aluminium electrolysis. Min. Proc. Extractive Metall. (Trans. Inst. Min. Metall. C), 144, C181–C187 (2005)
T. Reek et al., Successful dry restart of the hamburg smelter. Light Met., 461–466 (2008)
M. Pfeffer, F. Pfefferer, Kathodenblock aufweisend eine neuartige Nut-Geometrie (patent pending DE102016210693.7, submitted 15 June 2016)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 The Minerals, Metals & Materials Society
About this paper
Cite this paper
Friedrich, R. et al. (2017). Minimizing Cathode Voltage Drop by Optimizing Cathode Slot Design. In: Ratvik, A. (eds) Light Metals 2017. The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-319-51541-0_86
Download citation
DOI: https://doi.org/10.1007/978-3-319-51541-0_86
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-51540-3
Online ISBN: 978-3-319-51541-0
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)