| 摘要 |
<p>The HIsmelt process as disclosed in WO 96/31627 A1 (PCT/AU96/00197) consists of forming a molten bath of iron and slag, injecting metalliferous feed (oxides), solid carbonaceous material (coal and/or coke) and slag formers into the bath and smelting the metalliferous feed to metal. The process also consists of post-combusting the unoxidised reaction gases and transferring the generated heat to the bath to facilitate the smelting. In addition, a transition zone between the post-combustion zone and the quiescent metal zone is formed by injecting the charge together with a carrier gas into the bath, thus causing the metal and slag to be projected into the transition zone. The present application constitutes an improvement over the afore-mentioned application, in that lances/tuyères are inserted deep into the melt to provide oxygen for post-combustion of the unoxidised reaction gases and, in addition, to project splashes, droplets and streams of molten metal into the transition zone, which, in turn, fall back into the bath, thus effectively transferring heat from the post-combustion zone to the molten bath. The level of dissolved carbon in the bath is maintained at >/= 3 %, preferably > 4 %. The FeO level in the slag is maintained at < 8 %, preferably < 6 % or < 5 %. The amount of solid carbonaceous material injected as portion of the charge is such that the off-gas contains at least some carbon, preferably 5 - 90 % of the weight of dust in the off-gas, corresponding to 10 - 50 g/Nm<3>. Primary post-combustion is set at > 40 %, preferably > 50 % or > 60 %.</p> |
