Process for producing granular metal

Abstract

A technique that further improves the process for producing granular metal involves heating agglomerates and reducing and melting a metal oxide in the agglomerates. The process includes feeding agglomerates containing a metal oxide and a carbonaceous reducing agent onto a hearth of a moving hearth reduction melting furnace, heating the agglomerates to reduce and to melt the metal oxide, cooling the granular metal obtained by the heating, and discharging the cooled granular metal out of the furnace to recover the same. The agglomerates have an average diameter of not smaller than 17.5 mm are fed onto the hearth when the agglomerates are heated at a spread density of not lower than 0.5 on the hearth.

1 . A process for producing granular metal, the process comprising:
 feeding an agglomerate comprising a metal oxide and a carbonaceous reducing agent onto a hearth of a moving hearth reduction melting furnace;   heating the agglomerate, thereby reducing and melting the metal oxide and obtaining a granular metal;   cooling the granular metal; and   discharging the granular metal out of the furnace after cooling, thereby recovering the granular metal,   wherein the agglomerate has an average diameter of not smaller than 17.5 mm, and   the heating comprises heating the agglomerate at a spread density of not lower than 0.5 on the hearth.   
     
     
         2 . The process according to  claim 1 , further comprising:
 spreading a carbonaceous material on the hearth before the feeding, wherein the feeding comprises feeding the agglomerates on the carbonaceous material, thereby obtaining a single layer.   
     
     
         3 . The process according to  claim 1 , wherein the metal oxide is iron oxide. 
     
     
         4 . The process according to  claim 1 , wherein the moving hearth reduction melting furnace is a rotary hearth furnace. 
     
     
         5 . The process according to  claim 1 , wherein the metal oxide is steelmaking dust. 
     
     
         6 . The process according to  claim 1 , wherein the moving hearth reduction melting furnace comprises:
 an upstream area having capable of maintaining a temperature of from 1300° C. to 1450° C. and   a downstream area capable of maintaining a temperature of from 1400° C. to 1550° C.   
     
     
         7 . The process according to  claim 6 , wherein the downstream area is capable of maintaining a temperature higher than a temperature of the upstream area. 
     
     
         8 . The process of  claim 2 , wherein the metal oxide is iron oxide. 
     
     
         9 . The process of  claim 1 , wherein the average diameter of the agglomerate is not smaller than 18.5 mm. 
     
     
         10 . The process of  claim 1 , wherein the average diameter of the agglomerate is not smaller than 20 mm. 
     
     
         11 . The process of  claim 1 , wherein the average diameter of the agglomerate is not smaller than 17.5 mm and not more than 31 mm. 
     
     
         12 . The process of  claim 1 , wherein the average diameter of the agglomerate is not smaller than 17.5 mm and not more than 28 mm. 
     
     
         13 . The process of  claim 1 , wherein the heating comprises heating the agglomerate at a spread density of not lower than 0.6. 
     
     
         14 . The process of  claim 1 , wherein the heating comprises heating the agglomerate at a spread density of from 0.5 to 0.8. 
     
     
         15 . The process of  claim 1 , wherein the heating comprises heating the agglomerate at a spread density of not lower than 0.5 and not more than 0.7. 
     
     
         16 . The process of  claim 2 , wherein a thickness of the carbonaceous material after the spreading is not less than 3 mm. 
     
     
         17 . The process of  claim 2 , wherein a thickness of the carbonaceous material after the spreading is not more than 30 mm. 
     
     
         18 . The process of  claim 2 , wherein the carbonaceous material has a particle diameter of not more than 3.0 mm.