Granular metallic iron

Abstract

Metallic iron nuggets made by reducing-melt of a material containing a carbonaceous reductant and a metal-oxide-containing material, the metallic iron nuggets comprising at least 94% by mass, hereinafter denoted as “%”, of Fe and 1.0 to 4.5% of C, and having a diameter of 1 to 30 mm are disclosed.

1 . Metallic iron nuggets made by reducing-melt of a material containing a carbonaceous reductant and a metal-oxide-containing material, the metallic iron nuggets comprising at least 94% by mass, hereinafter denoted as “%”, of Fe and 1.0 to 4.5% of C, and having a diameter of 1 to 30 mm.  
   
   
       2 . Metallic iron nuggets according to  claim 1 , further comprising 0.20% or less of sulfur.  
   
   
       3 . Metallic iron nuggets according to  claim 1 , further comprising 0.02 to 0.5% Si and less than 0.3% Mn.  
   
   
       4 . Metallic iron nuggets according to  claim 1 , wherein the metallic iron nuggets are made by heating and reducing metal oxide in the material in a solid state, and further heating the resulting reduced iron in a reducing atmosphere so as to carburize and melt the resulting reduced iron and allow the resulting reduced iron to form nuggets while excluding by-product slag.  
   
   
       5 . Metallic iron nuggets according to  claim 1 , wherein the sulfur content of the metallic iron nuggets is reduced by adding a CaO source to the material to adjust the basicity (CaO/SiO 2 ) of a slag component in the material to 0.6 to 1.8 so as to allow slag produced during reducing-melt to trap sulfur therein.  
   
   
       6 . Metallic iron nuggets according to  claim 1 , wherein the sulfur content is less than 0.08%.  
   
   
       7 . Metallic iron nuggets according to  claim 1 , wherein the amount of the carbonaceous reductant in the material is adjusted so that the residual carbon content at a metallization ratio of 100% after reduction by heating is 1.5 to 5.0%.