The goal of this research is to improve an extractive metallurgy process based<p>on solvent extraction. This process should fit the exploitation of small local<p>copper-rich deposits. In these conditions, the plant has to be as compact as<p>possible in order to be easily transported from one location to a subsequent<p>one. Improved extraction kinetics could ensure a high throughput of the<p>plant despite its compactness. In addition, the extraction reagent should<p>not be damaging for the environnement. On this basis, we propose to use<p>ultrasound-assisted solvent extraction. The main idea is to increase the<p>extraction kinetics by forming an emulsion in place of a dispersion thanks to<p>the intense cavitation produced by ultrasound. The benefit of this method<p>is to improve the copper extraction kinetics by increasing the interfacial<p>surface area and decreasing the width of the diffusion layer. We studied the<p>implementation of an highly branched decanoic acid (known as Versatic-<p>10®acid) as a copper extraction reagent dispersed in kerosene.<p>Emulsification is monitored through the Sauter diameter of the organic<p>phase droplets in aqueous phase. This diameter is measured during pulsed<p>and continuous ultrasound irradiation via a static light scattering technique.<p>The phenomenon of emulsification of our system by ultrasound is effective,<p>and the emulsification process carried out in the pulsed ultrasound mode is<p>at least as efficient as the emulsification obtained under continuous mode.<p>No improvement of emulsification is observed beyond a threshold time of<p>the ultrasound impulse. This may be attributed to a competition between<p>disruption and coalescence. The use of mechanical stirring combined with<p>pulsed ultrasound allows to control the droplet size distribution.<p>In presence of ultrasound, the extraction kinetics of Versatic-10 acid is<p>multiplied by a factor ten, and therefore reached a value similar to the kinetics<p>observed without ultrasound with an industrial extractant such as<p>LIX-860I®(Cognis). Extraction kinetics measurements are carried out by<p>monitoring the copper ion concentration in the aqueous phase with an electrochemical<p>cell.<p>We conclude that ultrasound-assisted emulsification can be implemented<p>under certain conditions. Emulsification is a first step, and the following<p>destabilization step has to be studied. The device using ultrasound-assisted<p>emulsification should be followed by an efficient settling-coalescing device. A<p>possible solution would be to promote emulsion destabilization by increasing<p>the ionic strength with an addition of MgSO4, a salt that is not extracted<p>by the extraction reagent in the considered range of pH. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
| Identifer | oai:union.ndltd.org:ulb.ac.be/oai:dipot.ulb.ac.be:2013/210155 |
| Date | 25 March 2010 |
| Creators | Duhayon, Christophe |
| Contributors | Delplancke, Jean-Luc, Delplancke, Marie-Paule, Segers, Luc, Bartik, Kristin, Olivier, Marie-Georges, Frenay, Jean |
| Publisher | Universite Libre de Bruxelles, Université libre de Bruxelles, Faculté des sciences appliquées – Matériaux, Bruxelles |
| Source Sets | Université libre de Bruxelles |
| Language | French |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:ulb-repo/semantics/doctoralThesis, info:ulb-repo/semantics/openurl/vlink-dissertation |
| Format | 1 v. (ix, 304 p.), No full-text files |
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