Gaetan Lantagne - Academia.edu (original) (raw)

Papers by Gaetan Lantagne

Le présent projet de recherche résulte d'un intérêt industriel manifesté par la compagnie Zin... more Le présent projet de recherche résulte d'un intérêt industriel manifesté par la compagnie Zinc Électrolytique du Canada Ltée située à Valleyfield au Québec (C.E.Zinc). L'objectif principal de la thèse était d'obtenir des résultats dans des conditions très proches de la réalité industrielle. Par conséquent, l'expérimentation a été réalisée en cuvée, dans un réacteur de type uniformément agité, en utilisant de la poussière de zinc et des solutions de teneur industrielle comme matières premières. La méthodologie expérimentale utilisée a été basée sur des schémas statistiques reconnus -30X-BEHNKEN et PLACKETT-BURMANN (38)- de manière à obtenir des résultats significatifs sur une large plage expérimentale. Ces analyses statistiques ont démontré que toutes les variables étudiées sont statistiquement importantes -Co,T,Zn,Sb,pH, temps de réaction- et que plusieurs interactions sont manifestes révélant la nature multifactorielle de la cémentation du cobalt. L'analyse de BOX-BEHKEN étant une surface de réponse, il a aussi été démontré que l'optimum d'épuration des solutions de sulfate de zinc se situe à la frontière de l'espace d'expérimentation. Pour une solution industrielle typique, celà implique les conditions suivantes: Co++= 6 mgil; .Zn++ = 170 gil; pH iniitial = 3.45; Sb= 1mgil; t = 90 min. Conjointement à l'analyse statistique, des échantillons de particules ont été soutirés du réacteur de manière à obtenir une analyse complète des dépôts cémentés par différentes techniques d'analyse de surface telles que: la microscopie électronique à balayage (SEM), l'infrarouge par transformée de Fourier (FTIR), la spectroscopie AUGER et la diffractométrie R-X. Ces analyses ont confirmé la présence d'une mince couche de sulfates basiques de zinc-~< 1 µ- recouvrant la surface du zinc et des dépôts de cobalt dont le composé majoritaire est le ZnSO4 • 3Zn(OH)2 • 4H20. Pour concilier les résultats des différentes approches statistiques et des analyses de surface des particules, un modèle phénoménologique faisant intervenir une étape de diffusion à l'intérieur d'un mince milieu poreux à été développé. Ce modèle a permis de démontrer que les résultats cinétiques sont compatibles avec la présence d'un dépôt de sulfates en surface. Cependant, la conclusion la plus importante du point de vue industriel est que l'efficacité de la poussière de zinc en regard du transport de matière convectif solide-fluide est très faible, variant typiquement entre 4% @ 14%, et atteignant un maximum de 23% avec contrôle de pH pendant la première heure de réaction. Ces derniers résultats indiquent que quelques soient les conditions chimiques, il existe une pellicule indélébile de sulfates basiques de zinc en surface limitant la réaction; les moyens uniquement chimiques d'obtenir une meilleure efficacité de la poussière de zinc apparaissent donc limités. Cette conclusion conduit nécessairement à suggérer un moyen physiquement abrasif in-situ pour libérer la surface métallique de cette contrainte. Différents types de technologies peuvent alors être suggérées telles que les lits fluidisés ou jaillissants, mais il est clair que leur niveau d'abrasion doit être contrôlé pour favoriser le décapage de la couche de sulfates sans abîmer les dépôts cémentés. Une troisième possibilité réside dans la génération d'ultrasons en solution qui permettraient un décapage continu de la surface réactionnelle moyennant l'atteinte du point critique de cavitation. De l'avis de l'auteur, il est certainement possible d'obtenir une meilleure performance de la poussière de zinc utilisée en cémentation par une technologie plus appropriée que celle utilisée actuellement. Évidemment, tout changement de technologie implique des coûts considérables et il serait au préalable recommandé d'étudier l'influence des différents types de réacteurs mentionnés plus haut et de l'interaction de cette nouvelle technologie avec les facteurs chimiques

Computers & Chemical Engineering, Jun 1, 1988

ABSTRACT A method based on the penalty function concept is presented to solve simultaneous phase ... more ABSTRACT A method based on the penalty function concept is presented to solve simultaneous phase and chemical equilibria by minimization of the Gibbs free energy. To solve the underlying unconstrained problem, a comparison is made between two methods: a second-order Newton method and a quasi-Newton method. The algorithm enables one to determine the number of phases present at equilibrium as well as the composition of each component in each phase. Any thermodynamic model which predicts fugacities can be incorporated easily. Numerical results related to various systems that involve gases, liquids, solids and electrolytes are presented. Furthermore, the computational efficiency of the penalty function method is compared to another contemporary method which is based on a sequential quadratic programming algorithm.

Journal of The Electrochemical Society, 2017

Journal of Applied Electrochemistry, Jul 24, 2018

A pseudo two-dimensional model (P2D) was presented to describe the electrochemical behaviour of a... more A pseudo two-dimensional model (P2D) was presented to describe the electrochemical behaviour of a commercial 18650 cylindrical cell composed of graphite and LiFePO 4 (LFP) electrodes. Simulations were conducted by COMSOL MUL-TIPHYSICS 5.2. The model validation was done with experimental data taken from Hydro-Québec for a full range of Crates (currents). A mosaic model based on a Crate dependent particle radius in positive and negative electrodes was assumed. The reaction kinetics and diffusion in a solid phase were recognized as cell performance limiting factors in the flat area and in the steep area at the end of discharge of the cell voltage-capacity curve, respectively. Since the diffusion polarization in a solid phase played an important role in the steep area at the end of discharge of the cell voltage-capacity curve, a concentration dependent diffusion coefficient in LFP positive electrode was considered. Based on the fact that activation overpotential was a major polarization in the flat area of the cell voltage-capacity curve in addition to decreasing the particle radius at higher Crates , a contact resistance between the surface of the particles and the solid matrix was predicted. This contact resistance on the surface of active materials in the positive electrode described the feature of low electronic conductivity in LFP. There was a good agreement between the simulated results with experimental discharge data in a full range of Crates .

Journal of The Electrochemical Society, 2019

Hydrometallurgy, May 1, 1997

A performance study of four different cation-exchange membranes was conducted on laboratory and p... more A performance study of four different cation-exchange membranes was conducted on laboratory and pilot scale (172 cm2/membrane, model CS-0 from Asahi Glass Co.) electrodialysis cells, using Neosepta CMS from Tokuyama Soda Co.; Morgane CRA from Solvay; Selemion CHV from Asahi Glass Co. and Nafion 117 from DuPont, coupled with a Morgane ARA 17-10 anion-exchange membrane. Comparisons were made of the sulphuric acid recovery rate, water transport, metal leakage and energy intake for these membranes. Proton permselectivity and metal leakage, co-and counter-ion transport numbers of the CMS membrane were investigated using Hittorf's method and radiotracer methods. This study shows that electrodialysis is suitable for the treatment of zinc hydrometallurgy effluents. However, R&D work must still be done in order to improve and optimize the technology for its use in future industrial applications. In particular, research efforts must concentrate on the synthesis of affordable and stable cation-exchange membranes showing high selectivity towards protons.

Journal of The Electrochemical Society, Sep 1, 2022

Molten salt electrolysis is an efficient process to obtain metallic lithium but requires a consid... more Molten salt electrolysis is an efficient process to obtain metallic lithium but requires a considerable amount of energy. The use of a grooved diaphragm and rotating electrodes were studied using an advanced numerical model representing an experimental lithium electrolytic cell with the finality to reduce the required energy. Simulations were conducted using a turbulent (k-ε) model to solve the two-phase flow coupled to the transient mass transport inside a 2D axisymmetric electrolysis cell. The model also considers the recombination of Li with chlorine gas (Cl2), a backreaction that is detrimental to efficiency and energy consumption. The vertical diaphragm with grooves produces a reduction of 26.7% in energy consumption in comparison with the ungrooved design but increases by four times the amount of recombined lithium in the process. To decrease that recombination, the grooved diaphragm was inclined toward the anode. A vertical angle of 85° helps to reduce the energy consumption by 23.5% with approximately the same recombined lithium mass when compared to the vertical ungrooved design. The use of a rotating cathode with at an angular velocity of 0.25 rad s−1 results in a 40% decrease in energy consumption in addition to a decrease of 87.4% in metallic Li reconversion, in comparison with non-porous ungrooved diaphragm design.

Journal of The Electrochemical Society, 2022

Metallic lithium, which is a critical and strategic metal for the world’s production of energy st... more Metallic lithium, which is a critical and strategic metal for the world’s production of energy storage devices, is mainly produced from molten salt electrolysis. To increase the efficiency of the process, it is of utmost importance to prevent lithium recombination during the process to avoid energy waste. This research studies the behavior of the main variables involved in the reaction inside a Li -production experimental cell from the mass transfer, electrochemical and fluid dynamics standpoints. Simulations were done for a total electrolysis time interval of 600 s using a turbulent (k-ε) approach to solve the two-phase flow coupled to the lithium electrolysis process. To analyze the influence of cathode fluid dynamics in relation to the amount of recombined lithium, two configurations of the diaphragm were evaluated including the incorporation of a baffle at the bottom of the cell and the inclination of the diaphragm. The baffle reduced the amount of recombined lithium by 7 % , an...

Electrochimica Acta, 2018

Mass transfer and energy consumption of a lithium electrolysis cell, called gas-lift cell, is inv... more Mass transfer and energy consumption of a lithium electrolysis cell, called gas-lift cell, is investigated with a developed solver in open source package, OpenFOAM. The velocity distribution introduced by the bubbles, is solved by an Euler-Euler two-phase flow model, while the k-epsilon approach is used to solve the electrolyte turbulent flow. The nonuniform distribution of the bubbles and the gas coverage at the anode are influenced by the current density distribution. Infact, the electric and flow fields assumed to be weekly coupled. Moreover, the strong dependence between the potential field, current distribution, and ions concentration is taken into account. The solver is developed and validated, considering the strong coupling between different phenomena inside of the cell and at its boundaries. This model is general and can be used for the simulation of the concentration and electric fields inside any electrolysis cell.

Journal of Applied Electrochemistry, 2018

A 2D axisymmetric electrochemical model of a lithium experimental cell is solved using a finite e... more A 2D axisymmetric electrochemical model of a lithium experimental cell is solved using a finite element method. The model is considering the coupled effect of momentum, electric, kinetic and mass transfer phenomena. The dense diaphragm used in the setup, which is not hydraulically permeable, separates the cell into two regions: 1 (a) turbulent region, between the anode and the diaphragm, and 2 (a) laminar region between the diaphragm and the cathode. The k-epsilon model is used to solve the turbulent flow resulting from bubbles generation at the anode. A two-phase flow model is also developed to simulate the volume fractions of bubbles and electrolyte in the cell. The non-uniform bubbles distribution over the anode surface, derived from the non-uniform current distribution, has been added to the two-phase model. The effects of the diaphragm length, position and porosity on the electric and two-phase flow fields are simulated. In fact, the diaphragm position and length both influence the current distribution at the surface of electrodes and the velocity distribution in the cell, all of which influence ohmic and kinetic overpotentials. The results show that up to 40% of energy can be saved when running the lithium electrolysis cell with a shorter porous diaphragm located as far as possible from the anode. The maximum current density, found at the bottom corner of anode, is higher when the diaphragm is longer and when it is closer to the anode.

Journal of Applied Electrochemistry, 2017

A fully integrated mass transfer and electrochemical model of a lithium production cell solved us... more A fully integrated mass transfer and electrochemical model of a lithium production cell solved using a finite element method is presented. The coupled effect of momentum and mass transfer, kinetics, and electric fields is taken all into account. The turbulent flow resulting from the bubbles generated at the anode is solved based on a kmodel. The ohmic overpotential and hyperpolarization due to the bubbles are considered through a resistive layer and bubble coverage at the surface of the anode. Furthermore, the effects of the anode-cathode distance (ACD) and current density on the electric and concentration fields of the cell are simulated. The results of the transient simulation reveal that the diaphragm separates the cell in two regions & Elaheh Oliaii

Hydrometallurgy, 1997

Chemical Engineering Science, 2012

Gibbs free energy is applied to constrained equilibria. c Maximizing entropy is replaced by minim... more Gibbs free energy is applied to constrained equilibria. c Maximizing entropy is replaced by minimizing Gibbs coupled with an energy balance. c Adiabatic and non-adiabatic problems can be treated by Gibbs minimization. c Kinetic constraints allow the evolution of the quasi-equilibrium state with time.

Desalination, 2000

Iron and manganese can be removed from groundwater by a process which combines oxidation and micr... more Iron and manganese can be removed from groundwater by a process which combines oxidation and microfiltration (MF), especially when the concentrations of these metals are high and variable. The present experimental work focused on the MF of iron and manganese oxide suspensions in order to study the effects of the operating variables (tangential flow rate, pressure, metal feed concentrations) on permeate quality and permeation flux decline, i.e., membrane fouling. Artificial and natural groundwaters in which iron and manganese were previously oxidized were used to perform laboratory-scale MF experiments. The results show that the oxide particles, with sizes ranging from 1.5 to 5~m, were efficiently microfiltered even at high concentrations. Within the experimental limits, the effect of operating pressure appeared to be much more significant than the those of tangential flow rate and feed concentration. A relatively high and constant permeation rate of 0.5 m/h was obtained at a pressure below 10 kPa, whereas rapid permeation flux declines were observed at higher pressure. Both artificial and natural groundwaters always exhibited very similar behavior.