Skip to main content
European Commission logo print header
Zawartość zarchiwizowana w dniu 2022-11-21

Elimination of heavy metals, in particular zinc and nitrate ions, from industrial gas-scrubbing water

Cel



The iron and steel industry is resorting more and more frequently to galvanisation in order to enhance corrosion resistance of metals. Cold or hot rolled steel is coated with zinc (hot dip galvanizing or cold electrogalvanising), with aluminium or with zinc alloys such as Zn-Fe, Zn-Ni, Zn-Co, etc.

The coated steel then undergoes chemical and electrochemical post-treatments such as phosphating and/or passivation in order to enhance pain adhesion and/or passive corrosion resistance.

All these treatments inevitably give rise to effluent with high concentrations of metals (zinc, aluminium, chromium, nickel, etc) and anions (nitrates, sulphates, chlorides, fluorides, etc).

Law No 319/76 includes provisions for industrial waste emissions into surface waters or sewage systems.

Effluents produced by industrial treatments are usually collected separately in special storage tanks where concentrations are balanced and specific polluting agents are removed (chromate reduction, etc).

Even though conventional treatments such as coagulation and flocculating are essential, they are not sufficient to ensure that final effluents comply at all times with the limits set by current regulations. Further chemical-physical treatment, such as filtering and ion exchange, is therefore required. Such treatment causes management problems at both financial and operational level.

Metals thus collected are not finally disposed of, but - as a result of filter back-washing and resin regeneration - are returned to the waste treatment plant together with solution anions.

This project was aimed at testing the use of organic reagents which can combine with metals and certain anions to build low-solubility compounds.

More specifically, the research work was focused on zinc ions and nitrate anions. Both polluting agents are to be found in substantial quantities in emissions and they are difficult to dispose of.

Zaproszenie do składania wniosków

Data not available

System finansowania

Data not available

Koordynator

Zincor Italia SpA
Wkład UE
Brak danych
Adres
Via Circonvallazione
27057 Varzi Pavia
Włochy

Zobacz na mapie

Koszt całkowity
Brak danych