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Closing circuit of contaminated process streams: fundamental development of process technologies
- Bundesministerium für Bildung und Forschung (BMBF)
Fertigstellung des Projekts:
Abwasser / Abfall
Various industries produce large amounts of contaminated acidic or alkaline process solutions (e.g. the metal-producing and metal-processing industry or the galvanisation industry), which are disposed of as liquid waste streams. To improve material utilisation in these areas, the process streams would have to be cleaned of troublesome contaminants, with the subsequent closing of the processing circuits.
Within the framework of a joint project, it was the task of this subproject to select suitable processes for halogenide separation, based on laboratory investigations using synthetic alkaline and acidic solutions with high levels of salinity as well as real process solutions.
- The only process tested that could be used to separate the halogenides from strongly alkaline solutions was the process of nanofiltration. Ion exchangers and electrodialysis were found to be unsuitable. The various types of nanofiltration membranes produced by different companies all had sufficient stability in the pH range from 12-13, but varied strongly with regard to their separation and permeation capacities. Overall, the nanofiltration process could only be used for solutions for which the loss of a certain amount of valuable material was acceptable.
- Electrodialysis, on the other hand, proved to be a good way of separating chloride from sulphuric acid solutions and processing washing acids containing halogenides, although the loss of sulphuric acid as a valuable component was relatively high in most cases
Autor/Projektleiter: Michael Stelter ; Elke Niederschlag ; Michael Scheel
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