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Construction, testing and optimization of a low-waste electroplating plant operated without waste water to be drained
- Umweltbundesamt (UBA)
Fertigstellung des Projekts:
Umwelt- / Verfahrenstechnik
Anlagenbau, Modernisierung / Sanierung, Prozesstechnik
At the operation of conventional electroplating plants substantial quantities of special refuse to be deposited and large quantities of waste water result. The goals of the project consisted in lowering the quantities of waste and avoiding the waste water accumulation completely. The waste-water-free operation of the plant was reached, after the entire production process had first been designed for extremely economical water consumption.
The in-plant closed-loop circulation of materials streams at the plant for the galvanic and chemical coating of pourable small articles from steel (so-called drum commodity) ensures that the applied metals remain in the process. The closure of the materials streams allows a feedback of the production chemicals and a closed-loop circulation of the production auxiliary materials.
A regeneration and recirculation unit working on physical or electro-chemical basis is connected to each waste water and therefore waste-relevant process step, provides for concentration and feedback of the rinse water as well as cleaning of the process baths and ensures a removing of metals as well as brought in impurities. The small residual production waste water is evaporated in an energetically optimized evaporation plant. Thus distilled water is won, which goes back as rinse water into the process. As production residue only a small quantity of solved salt remains, which is deposited underground. In order to guarantee the long-term troublefree operation, each process step must be operated as closed system to avoid a mixture with materials from other process steps.
The residual substances from the galvanic sludge could be reduced by 75%, from the phosphatizing sludge by approx. 40 %. Acids, caustic solutions, chromating solutions and cyanide solutions did not appear in the residual substance balance. However, neutral salts accumulated and the content of other residual substances doubled, but amounted to only 5% of the total residual substance.
Autor/Projektleiter: Hans-Peter Damian
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