Siemens Metals Technologies has acquired the know-how for acid regeneration from Acreg Process Technology GmbH, Vienna, Austria, thus extending its portfolio for pickling plants in the steel industry. Aashish Gupta, who is responsible for the worldwide continuous casting und rolling mill business at Siemens Metals Technologies, explained, "By acquiring proven technologies of plants for regenerating pickling liquors and recycling of rinse water, we have complemented our range of solutions for cold rolling mills."

The surface of hot strips coming from hot rolling mills is pickled chemically with hydrochloric acid to remove the scale. These acidic pickling liquors are regenerated afterwards and used again in a closed circuit. This reconditioning process produces iron oxide as a by-product which can be rated as valuable raw material.

By expanding its know-how in pickling chemistry to include the regeneration of hydrochloric acid, Siemens Metals Technologies can now supply pickling plants, tandem pickling line connections and complete cold rolling complexes, including acid regeneration plants. The process for regenerating ferruginous hydrochloric acid pickling liquors enables the hydrochloric acid to be almost completely recovered in a closed circuit.

Both the spray-roasting process as well as the fluidized bed process are used as large-scale processes. Each of these systems offers specific advantages. The spray-roasting technology, which requires a somewhat lower investment and lower energy consumption, precipitates a very fine red oxide which can be used as the starting material in the ferrite and pigment industries, as well as for corrosion protection.

The fluidized bed process produces high-purity, dust-free oxides with a very low chloride content and a high apparent density, that can be used directly in the steelmaking process. Acreg has not only perfected both of these processes but already implemented them in a large number of projects.

The technologies purchased by Siemens Metals Technologies are used in reference projects in Europe, Russia, China, India and Central America.