Stainless steel without dust in Bochum

Washing machine drums, containers, beer barrels, car fuel tanks, seawater desalination plants - just some of the many modern products made of stainless steel. Manufacture of these materials starts in ThyssenKrupp Nirosta`s melt shops. The AOD process used here generates a great deal of dust which has to be removed from the waste gases before they are allowed to enter the atmosphere.

With emission regulations tightening significantly in recent years, ThyssenKrupp was quick to invest in pollution control. The Bochum steel mill of ThyssenKrupp Nirosta was equipped with a wet dust collection system which removed solids from the waste gases in the form of sludge for disposal.

The new dry dust collector put into operation on January 4, 2002 provides major ecological and economic advantages: The dry dust it extracts can be recycled by treatment and melting. The crude gas emerging from two converters is cooled before passing through a fabric filter system, where the solids are collected via a compressed air unit and conveyed to a silo. Following treatment to furnace size, the valuable raw materials chromium and nickel can be returned to the melting process. Other waste gases generated near the converter during charging and tapping are collected in a second unit and fed into the waste gas system.

This also prevents gases from escaping via the shop roof. 540,000 cubic meters of waste gas are released into the atmosphere each hour. One cubic meter of gas used to contain 50 milligrams of dust - already an almost negligible amount. This boundary value has now been reduced to as low as 10 milligrams: one of many steps ThyssenKrupp is taking to make skies even bluer over the Ruhr area.

For more information:
ThyssenKrupp Nirosta GmbH
Dr. Alfred Otto, Head of Marketing
Tel. +49 (0)2151 83 49 00
Fax +49 (0)2151 83 39 32
E-Mail: otto.alfred@ktn.thyssenkrupp.com