Lignite filter reduces emissions in steel plants

Cologne, Germany— Iron and steel scrap smelting accounts for approximately 34% of steel production worldwide, making it one of the most common iron and steel industry processes, one that is mainly carried out in electric arc furnaces. The thermal treatment of scrap containing paint, oil and other organic components can produce dioxin and furan, which in some cases necessitates additional environmental emissions reduction measures.

The reduction of dioxin emissions is particularly significant because in 1993 the EU Council of Ministers set a goal of substantially reducing such emissions by 2005, and the iron and steel industry accounts for over one million m3/h of the relevant dioxin emissions. Irrespective of this goal, in recent years some countries have set emissions limits for electrosteel production plants. Luxembourg was the first country to implement such regulations (as of January 1, 1997) which stipulates a limit of 0.1 ngTE/m3 (0.1 nanogram toxic equivalent per cubic meter of air).

The scope of the emissions requiring treatment and the cost necessitate a solution that is efficient as well as affordable. Adsorptive waste gas treatment using activated lignite HOK in an entrained phase process is one of the simplest and most inexpensive treatment solutions. In 1997, Luxembourg-based Arcelor, a subsidiary of Ares S.A., upgraded the dust removal system at their Schifflingen electrosteel plant by integrating a pioneering adsorptive entrained phase solution that uses activated lignite HOK. In 2001, this same system was also installed in ProfilARBED’s Esch-Deval and Differdingen plants. Entrained phase solutions are currently reducing PCDD/Fs at five European electrosteel plants and are hence also substantially reducing dioxin emissions at these facilities. According to EU estimates, this solution constitutes one of today’s best available technologies in this realm.

Activated lignite produced from Rhineland lignite provides outstanding separation efficiency.

The distinctive properties of lignite from the Rhine region combined with the activation parameters in the hearth furnace yield a type of activated coke (lignite) that has been in use for many years as an adsorption and filter medium for various waste gas and waste water applications.