Lukas Dion

• Doctor of Engineering
• Professor at Université du Québec à Chicoutimi

En partenariat avec aluminerie Alouette, un bilan de matière dynamique a été développé. Ce bilan considère les secteurs d’importances de l’aluminerie de façon à évaluer l’impact des matières premières et celui des composés qui sont recyclés à l’interne. L’objectif principal de ce modèle est de prédire les variations de la composition de l’aluminium...

Current efficiency is an important indicator used in the aluminum reduction technology. Values for this indicator are usually determined among potlines and they are not representative of the fluctuations that may occur in a single electrolysis cell. To measure or calculate an accurate value on a monthly basis would be a very interesting tool for pr...

Aluminerie Alouette recently studied the relationship between electrolysis cell operation and their impurities’ balance. It was observed in some cases that the concentration of impurities in the metal is lower than expected from raw material mass balance, mainly for iron, gallium, titanium and vanadium. These cells were inspected to find the cause...

In 2014, Alouette acquired a system to monitor the on-line anode current on two pots. This system, developed and supplied by WIT, reports all anodes current and the pot voltage for every second of operation. The following paper describes some of the resulting improvements that apply to the process control of the aluminum electrolysis cell. Current...

Aluminerie Alouette is one of the largest Aluminium Smelter in the world and produces several grades of metal purity. This year, a project was initiated with the goal of improving the predictability of the aluminium grade produced. The approach is to develop an additional tool for guiding the operation staff in taking the best operational decisions...

With increasing concerns about environmental performance and workplace security, the production of primary aluminum encounters many challenges. Among them is the introduction, dissolution, and distribution of large quantities of alumina into a small volume of electrolyte with a large horizontal surface using only a limited number of discrete inject...

Recent cell designs tend to use innovative sensors coupled with control systems for timely process decisions that provide a common usage of digital twins and improved competitiveness. As the cells are pushed closer to their operational limits, the preservation of the energy balance is a dominant limitation in the aluminum industry. Consequently, th...

In aluminium electrolysis cell, thermal balance represents a very sensitive aspect of process control and its optimization. This balance is strongly influenced by the side ledge behaviour, making it crucial for cell performance. Despite the existence of numerous studies on ledge, its precise behaviour remains difficult to assess in a timely manner...

Primary aluminium producers are inclined to maximize the cells’ current efficiency in order to enhance metal production and reduce production cost. For timely decisions, sodium content of the cathodic aluminium has been used as a performance indicator related to individual cell performances. This paper pinpoints the straightforward quantitative the...

A mathematical model has been developed to reproduce the tridimensional interface between bath and metal in an electrolysis cellElectrolysis cell. In the last year, the mathematical model has been adapted to consider alumina raftsAlumina rafts movements in tridimensional coordinates. To reproduce a bath-metal surface, the wave equation was solved a...

Alumina injectionsAlumina injection are the most frequent discrete events occurring in aluminum reduction cellsAluminum reduction cell. During each feeding, a significant fraction of the mass injected will float and create a raftRafts composed of aluminaAlumina and frozen bath which hinders the dissolutionDissolution rate of aluminaAlumina. However...

Using a specific description of the heat transferHeat transfer and diffusion coefficients, general mass transfer theory is applied to data available in the literature to identify their respective dissolutionDissolution rate. The following calculations using data from the literature are then compared to experimental work performed under laboratory c...

The behavior of alumina raft at the bath-metal interface in an electrolysis cell has been simulated by a numerical model in a past study. Further improvement on the numerical model led to broader application and a more «cell-like» scenario. The model now considers three distinct bath-metal interface phenomena. First, the transport wave stems from d...

For the aluminum industry, understanding each step of alumina addition to the electrolysis bath is critical to reach optimal process conditions. From the injection to the complete dissolution, several physical and chemical mechanisms are interacting: solid and fluid mechanics, heat transfer, phase change, and dissolution. The mathematical model pre...

There are numerous studies published in the literature related to alumina dissolutionAlumina dissolution rate in cryolite melts. However, such studies cover a broad range of results given in various formats. A new empirical equation was developed based on the results of an extensive parametric study using the gravimetric method on alumina disks. A...

Recent investigations on aluminum electrolysis cell demonstrated limitations to the commonly used tier-3 slope methodology to estimate perfluorocarbon (PFC) emissions from high-voltage anode effects (HVAEs). These limitations are greater for smelters with a reduced HVAE frequency. A novel approach is proposed to estimate the specific emissions usin...

The methodology used for accounting PFC emissions resulting from aluminum smelting have been developed nearly 20 years ago. There has not been any update on this methodology since 2008 and recently published research demonstrated possible avenues for improvements resulting in increased accuracy. Current models used in the aluminum industry quantify...

Perfluorocarbons are important contributors to aluminum production greenhouse gas inventories. Tetrafluoromethane and hexafluoroethane are produced in the electrolysis process when a harmful event called anode effect occurs in the cell. This incident is strongly related to the lack of alumina and the current distribution in the cell and can be clas...

Significant amounts of greenhouses gases are produced annually by aluminium smelters around the globe. Most of these emissions are carbon dioxide but perfluorocarbons are nonetheless an essential part of GHG inventories for aluminium smelters. The total mass of perfluorocarbons declared is estimated using a linear relationship between some process...

Anode effects (AE) are considered a nuisance for aluminium production due to the numerous negative impacts that they generate in an electrolysis cell. Previously, great efforts have been deployed to minimize the occurrence of this event. Using online anode current monitoring, Alouette introduced an algorithm to detect abnormalities prior to an AE,...

Aluminum smelters are known to be important producers of perfluorocarbons (PFC). These gases are generated when the localized overvoltage in the cell exceeds the threshold necessary to electrolyze the cryolite, hence generating an anode effect. When it remains localized, this event is difficult to identify and it can generate only a small amount of...

Since early 2014, Alouette has used a system provided by Wireless Industrial Technologies (WIT) to measure individual anode currents on two pots. The system works by measuring the adjacent magnetic field generated by the current for each anode hanger. This paper summarizes initial difficulties and how they have been overcome. Recent current measure...

Greenhouse gas (GHG) generation is inherent in the production of aluminium by a technology that uses carbon anodes. Most of those GHG are composed of CO2 produced by redox reaction that occurs in the cell. However, a significant fraction of the annual GHG production is composed of perfluorocarbons (PFC) resulting from anode effects (AE). Multiple i...

Primary aluminum production is generating a significant amount of greenhouse gases. CO2 is the dominant compound but during anode effects, perfluorocarbons (PFCs) are released as well. Even when no generalized anode effects are present, intermittent emissions of PFC have been reported in small concentrations but the root causes of these emissions a...

Primary aluminum production is generating a significant amount of greenhouse gases. CO2 is the dominant compound but during anode effects, perfluorocarbons (PFCs) are released as well. Even when no generalized anode effects are present, intermittent emissions of PFC have been reported in small concentrations but the root causes of these emissions a...

Current efficiency is an important indicator used in the aluminum reduction technology. Values for this indicator are usually determined among potlines and they are not representative of the fluctuations that may occur in a single electrolysis cell. To measure or calculate an accurate value on a monthly basis would be a very interesting tool for pr...

In 2014, Alouette acquired a system to monitor the on-line anode current on two pots. This system, developed and supplied by WIT, reports all anodes current and the pot voltage for every second of operation. The following paper describes some of the resulting improvements that apply to the process control of the aluminum electrolysis cell. Current...

Aluminerie Alouette recently studied the relationship between electrolysis cell operation and their impurities’ balance. It was observed in some cases that the concentration of impurities in the metal is lower than expected from raw material mass balance, mainly for iron, gallium, titanium and vanadium. These cells were inspected to find the cause...

Current efficiency is an important indicator used in the aluminum reduction technology. Values for this indicator are usually determined among potlines and they are not representative of the fluctuations that may occur in a single electrolysis cell. To measure or calculate an accurate value on a monthly basis would be a very interesting tool for pr...