[article]
| Titre : |
The (love & hate) role of entropy in process metallurgy |
| Type de document : |
texte imprimé |
| Auteurs : |
Halvard Tveit, Auteur ; Leiv Kolbeinsen, Auteur |
| Année de publication : |
2020 |
| Article en page(s) : |
8 p. |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Energie
Entropie (thermodynamique)
SiliconesLes silicones, ou polysiloxanes, sont des composés inorganiques formés d'une chaine silicium-oxygène (...-Si-O-Si-O-Si-O-...) sur laquelle des groupes se fixent, sur les atomes de silicium. Certains groupes organiques peuvent être utilisés pour relier entre elles plusieurs de ces chaines (...-Si-O-...). Le type le plus courant est le poly(diméthylsiloxane) linéaire ou PDMS. Le second groupe en importance de matériaux en silicone est celui des résines de silicone, formées par des oligosiloxanes ramifiés ou en forme de cage (wiki).
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| Index. décimale : |
668.9 Polymères |
| Résumé : |
Process metallurgy is the basis for the production, refining and recycling of metals and is based on knowledge of transport phenomena, thermodynamics and reaction kinetics, and of their interaction in high-temperature, heterogeneous metallurgical processes. The entropy concept is crucial in describing such systems, but, because entropy is not directly observable, some effort is required to grasp the role of entropy in process metallurgy. In this paper, we will give some examples of how entropy has a positive effect on efforts to reach the process objectives in some cases, while in other cases, entropy acts in contradiction to the desired results. In order to do this, it is necessary to have a closer look at both the entropy concept itself as well as at other functions like free energy and exergy since they encompass entropy. The chosen case is the production of silicon. It is the huge entropy change in the process that is utilized. The case is not chosen arbitrary. Indeed, it is the authors’ strong belief that silicon will be one of the foundations for the environmental and energy future planned for in the “Paris-agreement”. We will also explore relatively recent research in physics and thermodynamics that led to the description of the concepts like “dissipative systems and structures”. Dissipative systems are thermodynamically open systems, operating out of, and often far from thermodynamic equilibrium and exhibit dynamical regimes that are in some sense in a reproducible self-organized steady state. Such structures can arise almost everywhere provided this structure, feeding on low entropy resources, dissipates entropy generated in the form of heat and waste material in parallel with the wanted products/results. Examples range from metallurgical processes to the emergence of industrial symbiosis. |
| Note de contenu : |
- Introduction (based mainly on [1])
- The Paris Agreement - and the consequence for the energy usage
- Silicon - the metalloid hero faces new assignments for humanity
- The silicon processes
- The exergy destruction in silicon production
- Some thoughts about silicon production and the future |
| Référence de l'article : |
506 |
| DOI : |
https://doi.org/10.1051/mattech/2019028 |
| En ligne : |
https://www.mattech-journal.org/articles/mattech/pdf/2019/05/mt190044.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34446 |
in MATERIAUX & TECHNIQUES > Vol. 107, N° 5 (2019) . - 8 p.
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