Electric arc furnace dust (EAFD) contains between 20 and 40 % of zinc and 20 to 35 % of iron. Most of these dusts are landfilled, nevertheless, due to economical as well as ecological reasons, it should be aimed at a recycling of zinc and iron from EAFD. But the complex composition of the dust leads to difficulties at the treatment. Especially the halogens F and Cl cause problems, since they concentrate in the zinc product and thereby make it unsuitable for zinc-electrowinning. The main task of this work was to examine several possibilities for a selective halogen and lead removal during the dust recycling process, so that an impure and halogen-free zinc product can be won. For this, in a first step the behaviour and stability of several halogen-compounds was examined by thermodynamic calculations. In the next step, halogen-evaporation trials in the vertical retort as well as in the top blown rotary converter (TBRC) were performed. While the trials in the vertical retort failed completely, it was possible to reach excellent evaporation rates of more than 90 % for F and Cl as well as for Pb in the TBRC. It turned out that an effective halogen removal requires a hot-charging of the EAFD, so that undesired interactions between the halogens and other dust components, which cause an insufficient halogen removal, can be avoided.
|Translated title of the contribution||The halogen-problem in the treatment of electric arc furnace dust|
|Award date||7 Apr 2006|
|Publication status||Published - 2006|
Bibliographical noteembargoed until null
- EAFD electric arc furnace dust halogen removal fluorine chlorine selective evaporation zinc