REMOVAL OF DIOXINS AND FURANES FROM WASTE GASES OF A SINTERING PLANT BY USING LIGNITE COKE

Objective. Iron ore sintering plants count among the main sources of d ioxin and furane emissions in iron and steel mills. Since primary meas ures alone do not adequately cut such emissions, various dioxin reduct ion techniques are currently being tested at sintering plants. The aim in this respect is to obtain an efficient and, at the same time, econ omical method of dioxin reduction through integrated waste gas cleanin g. The following report sets out to show the efficacy of lignite coke in terms of dioxin level reduction in sintering processes and dust rem oval in an electrostatic precipitator. Summary. Thyssen Stahl AG (toda y Thyssen Krupp Stahl GmbH) has been conducting trials at a sinter str and with a suction area of 150 m(2) with the aim of reducing the dioxi n and furane levels. Initial operating results indicate that the conce ntrations of dioxins and furanes are lowered if lignite coke dust is a dded as an adsorbing agent to the flow of waste gas and the dust is th en removed in an electrostatic precipitator. The entrained-flow method , featuring coke dust as a PCDD/F reductant, is suitable for use in th is respect in sintering plants. It has also been found that the use of lignite coke dust offers a simple and thus inexpensive solution for r educing dioxin levels which can be realised at low cost and without an y additional accumulation of residual materials. By adding lignite cok e it has been possible to reduce the emissions to well below 0.5 ng TE /m(3) Because of the positive results, further optimisation trials inc luding a permanently demonstration purposes. A working group involving the participation of 6 German iron and steel mills has been formed in this connection.