Electrode Technology for Aluminum Production: Session I
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Stephan Broek, Kensington Technology Inc; Dmitry Eskin, Brunel University
Monday 2:00 PM
February 28, 2022
Room: 208A
Location: Anaheim Convention Center
Session Chair: Derek Santangelo, Hatch; Stephan Broek, Kensington Technology Inc
2:00 PM Introductory Comments
2:05 PM
Driving Continuous Improvement in a Modern GPC/CPC Testing Laboratory: Heather Riche'1; Leona Fletcher1; Maia Hunt1; Les Edwards1; 1Rain Carbon Inc.
Rain Carbon operates a central laboratory in the US to monitor GPC and CPC quality for six coke calcining plants. With a wide range of different coke qualities, it is critical to provide reliable results to control production and report accurate results to customers. The objective of this paper is to summarize Rain Carbon’s Quality Management System and Quality Control Programs to ensure consistent, high quality results. The Quality Control (QC) program monitors the performance of instrumentation for key analyses. Reference standards and/or control samples are analyzed at a designated frequency. To supplement this, the laboratory added a Quality Assurance (QA) program to monitor total measurement variability including sample preparation and analyst variability. Periodic Gage R&R studies are undertaken to develop precision limits for each test. As a final step, the company organizes global CPC Round Robins which give additional data and provide a valuable service to the industry.
2:30 PM
Machine Vision Sensor Based on Image Texture Analysis Applied to Industrial Anode Paste: Julien Lauzon-Gauthier1; Carl Duchesne2; Jayson Tessier1; 1Alcoa Corporation; 2Laval University
The development of rapid and non-destructive measurement methods for green anode quality assessment during production is important for the industry. It would improve process agility and robustness to face increasing variability in the raw materials. A machine vision sensor using a combination of image texture methods was used for extracting relevant paste textural features which were used as inputs of a Partial Least Squares regression model trained on the process variables. Previous work on laboratory anodes demonstrated sensitivity to pitch demand and particle size distribution. This sensor was then tested in a paste plant to assess its responsiveness to the industrial variability. The sensor was found sensitive to the variations in pitch during optimization experiments.
2:55 PM
Optical and Electrochemical Characterisation of Carbon Anodes with Varying Porosity and Coke Quality: Goril Jahrsengene1; Mahyar Farahani2; Hogne Linga3; Ann Mari Svensson2; 1SINTEF Industry; 2NTNU Norwegian University of Science and Technology; 3Hydro Aluminium AS
The performance of carbon anodes in aluminium production is suggested to be affected by both the coke quality (impurities, structure) and the physical properties of the anode (density, permeability, electric resistivity). To investigate the physical properties, different anodes with varying air permeability (0.5-3.5 nPm) were investigated optically and electrochemically. The voltage oscillations due to CO2 bubble formation on the horizontal anode surface appear to depend on the permeability of the anode, with lower permeability resulting in the highest oscillations. Laboratory-fabricated anodes with different sulfur content (1.42-5.54 wt%) and coke structure were characterized electrochemically. There were only small differences in the overpotential between all anodes investigated, however, a significantly higher double layer capacitance, a measure of the electrode-electrolyte interfacial contact area, was observed for anodes made of isotropic coke compared to the standard anisotropic coke.