Das Projekt "Treatment of electrolytes from a zinc electrolysis plant by eed (electro-electro-dialysis)" wird vom Umweltbundesamt gefördert und von Preussag-Weser-Zink durchgeführt. Objective: To build and operate a dialysis cell of industrial size together with the necessary ancillary equipment to test the EED process in long term commercial use. The EED allows a higher yield of zinc connected with considerable energy savings for removal of magnesium from the electrolyte compared with alternative possibilities. General Information: Preussag-Weser-Zink GmbH operates in Nordenham (Germany) a plant for the hydrometallurgical-electrolytic production of zinc with a capacity of 110 000 tons of electrolytic zinc per year. During the electrolysis an enrichment of the magnesium content of the electrolyte taken place. To limit this enrichment, a special treatment of a part of the electrolyte stream is necessary. Per ton of produced zinc generally 0.1 to 0.2 m3 of electrolyte are subjected to this treatment which consists of neutralizing the electrolyte with zinc. This leads to the formation of 30 to 70 Kg per ton of produced zinc, which is costly and energy intensive to dispose of. Within the framework of this project it is intended to subject a part of the magnesium containing neutral zinc sulfate (neutral lye) as a catholyte to an Electro-Electro-Dialysis (EED). In the EED more than 80 per cent of the zinc is separated in the usual quality at the cathode while a corresponding part of sulfate ions go into the anolyte and arerecirculated into the process. The zinc which has and been separated at the cathode in the EED is recovered in a second process step by selective precipitation. EED was developed in the research institute of Minemet in France and pilot testing took place at Preussag-Weser-Zink GmbH, during 12 months. The pilot plant consisted of 2-3 dialysis cells producing daily 3 Kg of zinc per cell. Results from the pilot trials confirmed the previous laboratory work. The demonstration plant consisted of a dialysis cell with five industrially sized cathodes of 1,2 m2 active surface and additional equipment for the treatment of the catholyte by selective precipitation. The production capacity of the demonstration plant was 50 kg zinc per day. From the laboratory work and the previous pilot tests for a 110,000. For a 110,000 tons zinc producing plant the estimated energy saving amounts to 1,400 TOE/year, in addition to which 91 000 000 000 KJ/a of primary energy are substituted with 32.3 000 000 000 KJ/a of electrical energy. On the basis of the above saving, the cost of handling 1 m3 of the electrolyte solution is calculated to be DM 168. compared to the current disposal cost (to a third party) of DM 198. The process is covered by a joint patent and a cooperation contract covers the relationship between Minemet and Preussag. Achievements: Important technical know-how for electrolytic processes using membranes was generated. Among others the cell with compartments for cathodes and anodes and the membranes fixing system had to be designed and materials and membranes chosen. The membrane IONAC MA 3475 from SYBRON CHEMICALS gave...
Das Projekt "Untersuchung nanostrukturierter Elektroden und des Elektrolyts" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Institut für Angewandte Physik durchgeführt. Im Teilprojekt TP2 sollen nanostrukturierte Elektroden mit erhöhter spezifischer Oberfläche erzeugt, untersucht und angewendet werden. Im TP3 sollen neue Speicherelektrolyte mit hoher Energie- und Leistungsdichte erforscht, entwickelt und zuletzt für einen Prototyp bereitgestellt werden. In jedem TP wird die Arbeit in drei Arbeitspakete (AP) organisiert: 'definition of concept' (Jahr 1), 'proof of concept' (Jahr 2+3), und 'demonstrator' (Jahr 4+5) sind mit den anderen Projektpartnern abgestimmt. Die AP's sind in Arbeitsschritte weiter unterteilt. AP2.1: Grundsätzliche Untersuchung des Zusammenhangs zwischen Oberflächenbeschaffenheit der Elektrode und Stromstärke von elektrochemischen Reaktionen. AP2.2: Entwicklung einer Methode zur Präparation von kontrollierten Nanoporen auf technisch anwendbaren Substraten. AP2.3: Kombination der optimierten Materialsysteme und Verfahren aus allen anderen Teilprojekten. AP3.1: Machbarkeit - redoxaktive ionische Flüssigkeiten als Speichermaterialien in RFBs. AP3.2: Suche, Entwicklung und Erprobung neuer anolytischer IL-Speichermaterialien. AP3.3: Kommerzialisierung der neuen Anolyte - Einsatz und Betrieb im Prototyp.