Electrode Technology for Aluminum Production: Anode Production - Green & Baked Anode Production/Modelling and Performance
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Derek Santangelo, Hatch

Wednesday 8:30 AM
March 17, 2021
Room: RM 28
Location: TMS2021 Virtual

Session Chair: Julien Lauzon-Gauthier, Alcoa Corporation


8:30 AM  
Start-up of a New “Smart & Green” Anode Plant: Christophe Bouche1; Xavier Genin1; Vincent Philippaux1; Jérôme Morfoise1; 1Fives
    In the early 2000s, the first industrial scale Rhodax® process Green Anode Plant (GAP) was started. More than 15 years later, the latest version of this technology was successfully commissioned to produce anodes at a higher production rate and for a higher amperage pot. The cumulated experience in the meantime, contributed to an evolution of the technologies, allowing us to meet today’s challenges: more stringent environmental requirements limiting emissions, reduced operator noise exposure, higher GAP operation efficiency and stable anode quality. It was also an opportunity to implement the use of digital technologies to enhance the Rhodax® and the preheating screw performance, monitor and maintain operation performance with advanced process control solutions. This paper summarizes the key lessons learnt from the latest reference and the performance achieved. It alsopresents the innovations implemented that open the door to new remote services for equipment performance and process stability enhancements.

8:50 AM  
The Steps to Optimize and Implement an Anode Stub Hole Cleaning Machine Modification: Valerie Langelier1; Derek Santangelo1; 1Hatch
    The market is becoming increasingly competitive and as a result, capital investments for projects are becoming increasingly difficult to justify. In some instances, the ''do nothing'' solution may impact a plant ability to maintain a stable and reliable operation. Therefore, an alternative approach must be taken to solve the problem in a cost-effective manner. Alcoa Deschambault faced this challenge when new process conditions resulted in their existing anode stub hole cleaning machine failing to adequately clean anodes. Manual cleaning was implemented to allow the anodes to properly mate with the yoke, but this led to ergonomics issues for the operators. This paper will elaborate on the approach taken to optimize a solution and overcome obstacles so that a cost-effective alternative to manual cleaning could be implemented.

9:10 AM  
Biocarbon in the Aluminium Industry: A Review: Samuel Senanu1; Asbjørn Solheim1; 1SINTEF
    Reduced fossil carbon footprint is currently an urgent trend in the metal-producing industries. Replacement of fossil carbon with bio-based equivalents is thus an important topic also for the primary aluminium industry. Several challenges related to biocarbon have been discussed in the literature, such as the availability of sustainable bio-based carbon materials for the aluminium industry in competition with other industries. Furthermore, the quality of materials made from bio-based sources tends to be inferior to the fossil-based materials, unless they undergo expensive treatment for adaptation to the aluminium industry. The most likely successful scenario appears to be a gradual introduction of biocarbon into the fossil carbon materials. One strategy being considered is replacement of the binder material with a bio-based binder in the production of ramming pastes or anodes. The current paper reviews candidate bio-based carbon materials, and their sustainability with respect to availability and efficient use is discussed.

9:30 AM  
Anode to Cathode Electrical Current Modelling for Cell Retrofit Application of Conductive Nails Technology: William Berends1; 1Alucelltech Inc.
    The electrical current density and distribution pattern between the anode and cathode is of fundamental influence on pot noise and current efficiency, also on cathode wear and pot-life, and potentially for low voltage anode effect. The reduction of harmful peak current densities can be achieved by controlling the ‘Electrical Contact Resistance’ (ECR) of the iron to carbon connections in the anode and cathode assemblies through selective use of conductive nails and altering the iron connection contact area. ANSYS and Maxwell optimization software are used to alter the ECR’s to improve the uniformity of current density on the anode and cathode active surfaces, and to reduce horizontal current vectors and magnetic force magnitude in the metal layer. Voltage drops are modelled to predict potential energy savings. Scenarios of increased amperage with reduced ‘Anode to Cathode Distance’ (ACD) are modelled to predict increased aluminium production while maintaining thermal balance and acceptable magnetic force distribution.

9:50 AM  
Managing Anode Performance with a Versatile Reactivity Analysis Method: Lorentz Petter Lossius1; Juraj Chmelar1; Viktorija Tomkute1; 1Hydro Aluminium AS
     Reactivity analysis has crucial importance for optimal electrolysis operation and is today monitored closely. Hydro Aluminium has been reviewing analysis with a thermogravimetric type analysis (TGA) system. The TGA instrument has continuous logging of mass loss to better than 0.01 wt%/min sensitivity and has close PID-regulated temperature control with a thermocouple sensor placed inside the test piece. This system has been in use to determine traditional reactivity properties, like total burn-off and collected dusting. Now the system is being tested with several temperature setpoints and TGA profile analysis.This versatile and sensitive TGA methodology is suited to investigate current anode reactivity trends like air reactivity burnoff increase year on year with changing raw materials and decreasing carboxy burnoff and dusting due to improved anode production.

10:10 AM Question and Answer Period