Aluminum Reduction Technology Across the Decades: An LMD Symposium Honoring Alton T. Tabereaux and Harald A. Øye: Harald Øye Honorary Session: Fundamentals in Anode and Cathode Technology - Joint Session with Electrode Technology
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Arne Ratvik, SINTEF; Marc Dupuis, GeniSim Inc.; Kristian Etienne Einarsrud, Norwegian University of Science and Technology
Wednesday 2:00 PM
March 17, 2021
Room: RM 28
Location: TMS2021 Virtual
Session Chair: Kristian Etienne Einarsrud, 1Norwegian University of Science and Technology (NTNU)
2:00 PM
Introductory Comments: Aluminum Reduction Technology Across the Decades: An LMD Symposium Honoring Alton T. Tabereaux and Harald A. Øye: Kristian Etienne Einarsrud1; 1Norwegian University of Science and Technology
Introductory Comments
2:05 PM
Forty Years of Trondheim International Course on Process Metallurgy of Aluminium: Michel Reverdy1; Vinko Potocnik2; 1Emirates Global Aluminium; 2Vinko Potocnik Consultant Inc
The Trondheim aluminium course, organized by Professor Harald Øye, took place for the first time in 1981 when given by Warren Haupin to participants from Norway. The success of this course led to the organization of an international course in 1982. Since its start, 2933 participants from 58 countries have attended the course, from both industry and academia. Experienced lecturers from many different countries and lively interaction with participants, have contributed to the success of the course. Lectures presented basics and fundamentals of aluminium electrolysis, practical knowledge of potline operation and control as well as a review of technological progress and innovations in aluminium reduction technology. The course has played an important role in connecting research to practice, setting industrial production on a scientific basis through attendees carrying this knowledge to their smelters. This paper reviews the most important subjects covered in the course during the last forty years.
2:45 PM
Establishing a Chemical Model of the Melt in the Cathode: Lorentz Petter Lossius1; Harald Arnljot Øye2; 1Hydro Aluminium AS; 2NTNU
From 1990 Harald A. Øye supervised work to establish a model of the chemistry of the catholyte, the electrolyte in the carbon cathode during start-up and operation of Hall Héroult cells for both semi-graphitic and graphitic blocks. First part, lab scale, P. Brilliot tested a range of carbon materials and electrolyte compositions, running electrolysis for less than one hour to a few days. After, the cathode with frozen melt was cross sectioned and XRD showed the sequential change from electrolyte to catholyte. Full scale, Lorentz Petter Lossius collected cores from cathodes from cells stopped after 10 days to 2700 days. The results and understanding from the lab scale work could then be extrapolated and modified to the chemical processes occurring through the life-time of the cells. The paper recounts key analytical experiences than and today, and presents the set of chemical equations and associated thermodynamics.
3:05 PM
Heating New Anodes Using the Waste Heat of Anode Butts Establishing the Interface Thermal Contact Resistance: Marc Dupuis1; Kristian Etienne Einarsrud2; Henrik Gudbrandsen2; 1GeniSim Inc.; 2Norwegian University of Science and Technology (NTNU)
In order to be able to assess the rate of heat transfer between a new anode and an anode butt, it is critical to measure the interface thermal contact resistance between them. For that purpose, a lab experiment has been setup and tests have been carried out to record the thermal response of the system after a cold anode block is put in contact with a hot anode block.Finally, a model of the same system has been developed in order to identify the value of the thermal contact resistance that permit to reproduce the thermal experimental thermal response.
3:25 PM
Forty Years of Cathode Block Evolution at EGA: Michel Reverdy1; Mustafa Mustafa1; Mohamed Boraie1; 1Emirates Global Aluminium
Emirates Global Aluminium (EGA), initially Dubai Aluminium (DUBAL), started operation in 1979 in its Jebel Ali smelter, consisting of Kaiser P69 cells. In 1990/1991 a fourth potline was started with improved lining, called D18 Technology, increasing potlife to approximately 2600 days. Subsequent DUBAL expansions with CD20/D20 Technology started in 1996-2006, using 30% graphitic blocks, whose best average life was 2150 days. These were replaced by graphitized blocks in the second generation, with best life of 1880 days. Newer EGA technologies; DX, DX+ and DX+ Ultra, use graphitized and impregnated graphitized blocks, the former having first generation average life of 1780 days and the latter 1950. In 2015-2018, the D18 potlines were modernized to D18+ Technology having 100 % graphitic blocks. In this paper, the evolution of cathode blocks, their performance and potlife, across all pot technologies at EGA will be presented, including collector bar design and transitioning to copper inserts.
3:45 PM
Wetting of Carbon Cathodes by Molten Electrolyte and Aluminium: Samuel Senanu1; Arne Petter Ratvik1; Zhaohui Wang1; Tor Grande2; 1SINTEF; 2NTNU Norwegian University of Science and Technology
The extent to which the carbon cathode is wetted by molten electrolyte or molten aluminium metal is important for understanding the cathode wear during aluminium electrolysis. The present paper reports on a laboratory study of the wettability of four different carbon materials using the immersion-emersion technique. The effect of polarization of the carbon cathode on the wettability was also included in the study. The measurements demonstrated that the carbon material is poorly wetted by the molten electrolyte or the metal. After polarization of the carbon in the cathodic direction the cathode became quickly wetted by the molten electrolyte. The presence of aluminium during the experiments resulted in enhanced wettability by the molten electrolyte. The carbon materials were analyzed by microscopy after the experiments and formation of Al4C3 was observed on the surfaces of the materials. The role of sodium in relation to enhanced wettability by molten electrolyte is discussed.
4:05 PM Question and Answer Period