Process for zinc removal from oxide-containing iron sources

Abstract

For removing zinc from oxide-containing iron sources, the iron source is in form of lump having a minimum grain size of 5 mm supplied together with lumpy reducing agents to a shaft-like muffle furnace being adapted to be gas-tightly closed. The muffle furnace is externally heated, for which purpose combustion chambers (2 and 3) are provided. Within the upper portion of the muffle furnace (1), the furnace charge flows through a pre-heating and pre-reduction zone (4) and subsequently to a reduction zone (5) before the reduced material is being discharged. Volatized zinc is withdrawn together with reaction gases at at least one cross-sectional plane located between the supply end and the discharge end of the muffle furnace, preferably located at the level of the upper end of the reaction zone (5). The apparatus for performing this process consists of a muffle furnace (1) which is adapted to be gas-tightly closed at its supply end and its discharge end and having within its wall and between said both ends gas outlet openings (10) which enter by by-passing the or extending through the heating means, for example combustion chambers (2, 3), arranged externally of the muffle furnace. Preferably, several combustion chambers are provided in axial direction of the muffle furnace, the gas outlet openings (10) being connected to conduits (11) arranged between the combustion chambers. The reduction gases can, after having separated the zinc, be recycled to one combustion chamber (2, 3) (FIG. 1).

Dependencies are inferred from the claim text.