Elimination of pollution and utilization of waste products from the pickling of stainless steel and high-nickel alloys

Ziel

We have carried out an exhaustive and critical bibliographical research on existing process, and studied - in cooperation with other specialized research centers - different process of treatment and valorization of used baths obtained with UG 3P process.

The main tests have concerned their physical chemistry (precipitation, distillation, extraction, ions exchangers) and electrochemistry techniques (electrolysis).

It has been proved that fluorhydric acid forms with iron and chromium very stable components, hardly separable, when using ion exchangers or extraction, they lead to poor rates. However, selective precipitation, distillation or electrolysis techniques, associated together or not, give an entire conformity towards environment and a partial valorization of fluorine and nickel.

Different process of valorisation are included. The new techniques should now be tested on industrial pilot.
All stainless steel or high nickle alloy production lines include a cleaning treatment employing pickling.

This may be located at two points in the production process:

- after hot rolling;
-after cold rolling and before finishing (kin-pass, etc.).

Pickling may be either a batch process (for plate) or a continuous process (for sheet, wire rod).

In the course of the pickling process, the baths become depleted as the acid concentration drops and salt sludges are formed. They must therefore be renewed at intervals.

The spent baths are neutralized, but this operation nonetheless remains severely detrimental to the environment. In addition, the elements contained in the discarded waste have a considerable market value.

The aim of the proposed project is therefore to investigate the possibility of recovering the metal elements contained in the baths both in order to separate them as environmental pollutants and with a view to their re-use.

Programm/Programme

ECSC-WORKENV 5C - Fifth research programme (ECSC) "Technical control of nuisances and pollution at the place of work and in the environment of iron and steel works", 1985-1989

Thema/Themen

4 - Wastes

Aufforderung zur Vorschlagseinreichung

Data not available

Finanzierungsplan

Data not available

Koordinator

UGINE ACG

EU-Beitrag

Keine Daten

Adresse

71130 Gueugnon
Frankreich

Gesamtkosten