Environmental Aspects and Recycling of Filter Dusts by Direct Injection or Use of Agglomerates in Shaft Furnaces

In the last decades the recycling of filter dusts of the iron and steel industry has become more and more important due to environmental as well as economical reasons. Beside of so-called end of pipe technologies, processes are required which ensure an efficient waste management with regard to productivity and profitability of steelworks. In this context the development of integrated systems is necessary to recover and to recycle valuable components. This paper describes possible techniques for an integrated treatment of filter dusts. On the one hand the injection of filter dusts in shaft furnaces is studied. For the trials a laboratory injection rig is used which simulates the injection of solids under conditions similar to the blast furnace. On the other hand the use of briquettes and pellets with embedded carbon in a shaft furnace is investigated by means of laboratory and industrial pilot trials. The results will be described and discussed with regard to the reduction behaviour of different coal-dust-mixtures.