Community Research and Development Information Service - CORDIS


Final report on Contract No 7215-PP/003, 1 July 1997 to 31 December 2000

An important evolution of pickling technology has been the introduction of processes based on solutions containing H(2)SO(4), HF and stabilised H(2)O(2). The elimination of HNO(3) drastically reduces the pollution problems caused by toxic vapours and exhaust solutions. The development of a suitable recovery technology for new pickling processes offers the opportunity to European stainless steel producers to solve definitively any environmental problem, saving the high costs of exhaust solutions treatment and sludge disposal.

Crystallisation is a simple technology which allows the recovery of the free acids by the elimination of metals from the exhaust solution as nickel(2+) and iron(2+) sulphates. A special electrolyser was developed, with the purpose of producing iron(3+) ions and providing more effective crystallisation of the solution. The main objective of the present project is the technical and economic validation of the proposed technology by means of a prototype plant.

Results obtained by the prototype were unsatisfactory, but subsequently two technologies turned out to be solutions for the recovery of free acidity and bonded acidity: electrodialysis and PMF.

The main conclusions are:
- The objective of zero-waste can be achieved by both electrodialysis and PMF technology.
- The absence of solid waste represents the main economic advantage.
- The recovery of metals is likewise essential to achieving positive economic validation.
- PMF process results are more interesting, considering the better economic performance and the higher reliability of adopted technologies.

Additional information

Authors: MANCIA F, CSM, Rome (IT)
Bibliographic Reference: EUR 20302 EN (2002), pp.55. Euro: 8.50
Availability: EUR-OP reference: KI-NA-20302-EN-S Available from EUR-OP sales agents. URL:
ISBN: ISBN: 92-894-3442-2
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