The Experts below are selected from a list of 14571 Experts worldwide ranked by ideXlab platform
Markus A. Reuter - One of the best experts on this subject based on the ideXlab platform.
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Process knowledge, system dynamics, and metal ecology
Journal of Industrial Ecology, 2004Co-Authors: E V Verhoef, Gerard P.j. Dijkema, Markus A. ReuterAbstract:A key principle in industrial ecology is the cyclic use of materials, a characteristic of natural ecosystems but a challenge in economic systems. Indeed, in society, metal retention, that is, the ongoing use or ready availability of metal in the economy between the life-cycle stages of resource extraction and final disposal back into the lithosphere, is finite because of the limited grade of secondary (recycled) metals. Currently, the utility of metals is maintained through the addition of high primary (virgin) metals, bringing the concentration of the recycled metals to desired levels. This mixing with high-grade primary metals keeps these recycled metals in the cycle. Long term, this practice of dilution of the undesired substances prevents a closure of the material cycles, whereas recovery without dilution reduces the quality (or quantity) of recycled metals. Metals participate in a system of linked cycles and thus cannot be produced or recovered independently from one another. The metal wheel is introduced in this article as a concise but powerful instrument for the communication of available Process knowledge in Process Metallurgy, the science and technology of producing metals from natural ores and societal raw materials, residues, and end-of-life products. It summarizes the chemical and physical linkages between metals found in ores and the set of metallurgical Processes that has been developed to accommodate these linkages. A dynamic mass-flow model is introduced to characterize the global metal cycles. The model facilitates the visualization of the evolution of their structure and technological content. To illustrate the interdependency of metal cycles using the metal wheel and the dynamic model, the transition to lead-free solder is evaluated. Neglect of metal-cycle linkages and dynamics in policy formulation may lead to a shortage of lead substitutes. In case of an extended ban on lead, both the availability and recovery of a range of metals will be affected.
E V Verhoef - One of the best experts on this subject based on the ideXlab platform.
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Process knowledge, system dynamics, and metal ecology
Journal of Industrial Ecology, 2004Co-Authors: E V Verhoef, Gerard P.j. Dijkema, Markus A. ReuterAbstract:A key principle in industrial ecology is the cyclic use of materials, a characteristic of natural ecosystems but a challenge in economic systems. Indeed, in society, metal retention, that is, the ongoing use or ready availability of metal in the economy between the life-cycle stages of resource extraction and final disposal back into the lithosphere, is finite because of the limited grade of secondary (recycled) metals. Currently, the utility of metals is maintained through the addition of high primary (virgin) metals, bringing the concentration of the recycled metals to desired levels. This mixing with high-grade primary metals keeps these recycled metals in the cycle. Long term, this practice of dilution of the undesired substances prevents a closure of the material cycles, whereas recovery without dilution reduces the quality (or quantity) of recycled metals. Metals participate in a system of linked cycles and thus cannot be produced or recovered independently from one another. The metal wheel is introduced in this article as a concise but powerful instrument for the communication of available Process knowledge in Process Metallurgy, the science and technology of producing metals from natural ores and societal raw materials, residues, and end-of-life products. It summarizes the chemical and physical linkages between metals found in ores and the set of metallurgical Processes that has been developed to accommodate these linkages. A dynamic mass-flow model is introduced to characterize the global metal cycles. The model facilitates the visualization of the evolution of their structure and technological content. To illustrate the interdependency of metal cycles using the metal wheel and the dynamic model, the transition to lead-free solder is evaluated. Neglect of metal-cycle linkages and dynamics in policy formulation may lead to a shortage of lead substitutes. In case of an extended ban on lead, both the availability and recovery of a range of metals will be affected.
Gisselbrecht Matthieu - One of the best experts on this subject based on the ideXlab platform.
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Simulation des interactions hydrodynamiques entre inclusions dans un métal liquide : établissement de noyaux d’agrégation dans les conditions représentatives du procédé de flottation
HAL CCSD, 2019Co-Authors: Gisselbrecht MatthieuAbstract:Inclusion cleanliness remains a major challenge faced in Process Metallurgy in liquid phase. Flotation, the main Process used in secondary Metallurgy to remove inclusions, consists in injecting gas bubbles into the reactor. Rising gas bubbles entrap the biggest inclusions at their surface or in their wake. Besides, they promote collision and aggregation among particles. A 3D numerical model has been developed in order to quantify the roles of the prevailing phenomena on aggregation dynamics between inclusions in the vicinity of bubbles. At inclusion (mesoscopic) scale, the turbulent flow is locally modeled by a steady plane shear flow which is solved using a lattice-Boltzmann method. The coupling between both liquid and solid phases is ensured using an immersed boundary method. This method resolves the hydrodynamic perturbation induced by particles, and hence their interactions that are, in turn, used to update their Lagrangian tracking. The conducted numerical simulations bring out the influence of hydrodynamic effects on inclusion behavior. Collision cross sections have been determined from which ensuing aggregation kernels have been calculated. Such cross sections could provide macroscopic models to represent local particle dynamics. A first application of these results is presented to calculate aggregation frequencies in bubble swarms in a channel flow reactor that was simulated using DNS. Additionally, evolution of inclusion populations in molten steel has been determined from RANS simulation of a liquid steel ladle by means of a global population balance implementing the aggregation kernels determined in the present work.La propreté inclusionnaire reste un enjeu majeur en élaboration des métaux par voie liquide. La flottation, principal procédé retenu en métallurgie secondaire pour éliminer les particules d’inclusions, consiste à injecter des bulles de gaz au sein du réacteur. Lors de leur ascension, les bulles vont capter les plus grosses inclusions et favoriser la collision et l’agrégation des particules. Dans le but de quantifier les phénomènes influents à l’échelle des inclusions sur la dynamique d’agrégation entre deux inclusions à proximité des bulles, un modèle numérique 3D a été développé. L’écoulement local est modélisé par un cisaillement plan permanent et résolu par une méthode de Boltzmann sur réseau. Le couplage entre les particules et le fluide a été assuré par une méthode de frontière immergée permettant de calculer la perturbation hydrodynamique engendrée par la présence des particules et de mettre à jour les interactions entre particules pour leur suivi lagrangien. Les simulations numériques réalisées ont mis en évidence que les effets hydrodynamiques ont une influence non négligeable sur le comportement des inclusions. Des sections efficaces de collision ont pu être extraites, à partir desquelles ont été calculés des noyaux d’agrégation, données macroscopiques rendant compte des effets à petite échelle. Une première application de ce travail a été menée avec le calcul des fréquences d’agrégation d’un train de bulle dans un réacteur canal à partir de résultats de simulations DNS. Les noyaux d’agrégation ont également été exploités en vue de déterminer, à partir de résultats RANS de l’hydrodynamique d’une poche d’acier, l’évolution de la concentration d’inclusions par un bilan de population global
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Simulation of hydrodynamic interactions between inclusions in liquid metal : determination of aggregation kernels in representative conditions of flotation Process
2019Co-Authors: Gisselbrecht MatthieuAbstract:La propreté inclusionnaire reste un enjeu majeur en élaboration des métaux par voie liquide. La flottation, principal procédé retenu en métallurgie secondaire pour éliminer les particules d’inclusions, consiste à injecter des bulles de gaz au sein du réacteur. Lors de leur ascension, les bulles vont capter les plus grosses inclusions et favoriser la collision et l’agrégation des particules. Dans le but de quantifier les phénomènes influents à l’échelle des inclusions sur la dynamique d’agrégation entre deux inclusions à proximité des bulles, un modèle numérique 3D a été développé. L’écoulement local est modélisé par un cisaillement plan permanent et résolu par une méthode de Boltzmann sur réseau. Le couplage entre les particules et le fluide a été assuré par une méthode de frontière immergée permettant de calculer la perturbation hydrodynamique engendrée par la présence des particules et de mettre à jour les interactions entre particules pour leur suivi lagrangien. Les simulations numériques réalisées ont mis en évidence que les effets hydrodynamiques ont une influence non négligeable sur le comportement des inclusions. Des sections efficaces de collision ont pu être extraites, à partir desquelles ont été calculés des noyaux d’agrégation, données macroscopiques rendant compte des effets à petite échelle. Une première application de ce travail a été menée avec le calcul des fréquences d’agrégation d’un train de bulle dans un réacteur canal à partir de résultats de simulations DNS. Les noyaux d’agrégation ont également été exploités en vue de déterminer, à partir de résultats RANS de l’hydrodynamique d’une poche d’acier, l’évolution de la concentration d’inclusions par un bilan de population global.Inclusion cleanliness remains a major challenge faced in Process Metallurgy in liquid phase. Flotation, the main Process used in secondary Metallurgy to remove inclusions, consists in injecting gas bubbles into the reactor. Rising gas bubbles entrap the biggest inclusions at their surface or in their wake. Besides, they promote collision and aggregation among particles. A 3D numerical model has been developed in order to quantify the roles of the prevailing phenomena on aggregation dynamics between inclusions in the vicinity of bubbles. At inclusion (mesoscopic) scale, the turbulent flow is locally modeled by a steady plane shear flow which is solved using a lattice-Boltzmann method. The coupling between both liquid and solid phases is ensured using an immersed boundary method. This method resolves the hydrodynamic perturbation induced by particles, and hence their interactions that are, in turn, used to update their Lagrangian tracking. The conducted numerical simulations bring out the influence of hydrodynamic effects on inclusion behavior. Collision cross sections have been determined from which ensuing aggregation kernels have been calculated. Such cross sections could provide macroscopic models to represent local particle dynamics. A first application of these results is presented to calculate aggregation frequencies in bubble swarms in a channel flow reactor that was simulated using DNS. Additionally, evolution of inclusion populations in molten steel has been determined from RANS simulation of a liquid steel ladle by means of a global population balance implementing the aggregation kernels determined in the present work
Gerard P.j. Dijkema - One of the best experts on this subject based on the ideXlab platform.
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Process knowledge, system dynamics, and metal ecology
Journal of Industrial Ecology, 2004Co-Authors: E V Verhoef, Gerard P.j. Dijkema, Markus A. ReuterAbstract:A key principle in industrial ecology is the cyclic use of materials, a characteristic of natural ecosystems but a challenge in economic systems. Indeed, in society, metal retention, that is, the ongoing use or ready availability of metal in the economy between the life-cycle stages of resource extraction and final disposal back into the lithosphere, is finite because of the limited grade of secondary (recycled) metals. Currently, the utility of metals is maintained through the addition of high primary (virgin) metals, bringing the concentration of the recycled metals to desired levels. This mixing with high-grade primary metals keeps these recycled metals in the cycle. Long term, this practice of dilution of the undesired substances prevents a closure of the material cycles, whereas recovery without dilution reduces the quality (or quantity) of recycled metals. Metals participate in a system of linked cycles and thus cannot be produced or recovered independently from one another. The metal wheel is introduced in this article as a concise but powerful instrument for the communication of available Process knowledge in Process Metallurgy, the science and technology of producing metals from natural ores and societal raw materials, residues, and end-of-life products. It summarizes the chemical and physical linkages between metals found in ores and the set of metallurgical Processes that has been developed to accommodate these linkages. A dynamic mass-flow model is introduced to characterize the global metal cycles. The model facilitates the visualization of the evolution of their structure and technological content. To illustrate the interdependency of metal cycles using the metal wheel and the dynamic model, the transition to lead-free solder is evaluated. Neglect of metal-cycle linkages and dynamics in policy formulation may lead to a shortage of lead substitutes. In case of an extended ban on lead, both the availability and recovery of a range of metals will be affected.
Steven G. Jansto - One of the best experts on this subject based on the ideXlab platform.
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The Integration of Process and Product Metallurgy in Niobium Bearing Steels
MDPI AG, 2018Co-Authors: Steven G. JanstoAbstract:A review of the technological integration of both the Process and physical metallurgical advancements of value-added niobium (Nb) microalloyed thermo-mechanical controlled Process (TMCP) steels have evolved into the development of higher quality steels for more demanding end user requirements. The connection of Process and physical Metallurgy is evolving through the integration of research that is aimed at improving product quality. However, often the connection of the Process metallurgical parameters is not reported, especially with industrial data. The importance of this innovative metallurgical connection is validated by the market demand for reduced fuel consumption, improved quality, and CO2 emissions in both the automotive and construction sectors. This situation has further increased the demand for new higher quality Nb-bearing steel grades. This integrative Process/physical metallurgical (IP/PM) approach applies to both low and high strength steel grades in numerous applications. Often, the transition from laboratory melted and TMCP to the production scale is challenging. The methodology, Process control, and key production steps that are required during the melting, ladle Metallurgy, continuous casting, thermal, and hot rolling production conditions often vary significantly from the laboratory conditions. Understanding the reasons and corrective action for these variations is a critical product development success factor. These Process Metallurgy parameters for the industrial melting, casting, reheating, and hot rolling of Nb grades are connected and correlated to the resultant microstructures, physical Metallurgy, and mechanical properties. These advanced high strength steels are microalloyed with Nb, V, Ti and/or other elements, which affect the austenite-ferrite transformation. Niobium enables the achievement of substantial grain refinement when the plate or sheet is rolled with the proper reheat, hot reduction, and thermal schedule. A recently developed key metallurgical transition is in progress applying this integrative approach with the use of MicroNiobium. A reduction of Mn and C levels with the complementary refinement of the microstructural grain size through MicroNiobium additions improves the robustness of the steel to better accommodate some Process Metallurgy variations. Applications are evolving in lower strength steels with Nb to achieve complementary grain refinement