Surface-coated reduced iron, method for making the same, and method for melting the same

Abstract

A method for making surface-coated reduced iron includes the step of coating the surface of reduced iron with a tar emulsion. Preferably, the tar emulsion includes at least one hydrocarbon-based material selected from the group consisting of natural petroleum tar, coal tar, pitch, asphalt, liquefied coal, and residual oil from petroleum refining; a surfactant; and water. More preferably, the tar emulsion contains 60 to 80 percent by mass of the hydrocarbon-based material, 0.1 to 1 percent by mass of the surfactant, and the balance being substantially water.

What is claimed is:  
     
         1 . A surface-coated reduced iron having the surface coated with a tar emulsion.  
     
     
         2 . The surface-coated reduced iron according to  claim 1 , wherein said tar emulsion comprises at least one hydrocarbon-based material selected from the group consisting of natural petroleum tar, coal tar, pitch, asphalt, liquefied coal, and residual oil from petroleum refining; a surfactant; and water.  
     
     
         3 . The surface-coated reduced iron according to  claim 2 , wherein said tar emulsion comprises 60 to 80 percent by mass of the hydrocarbon-based material, 0.1 to 1 percent by mass of the surfactant, and the balance being substantially water.  
     
     
         4 . A method for making a surface-coated reduced iron comprising the step of coating the surface of a reduced iron with a tar emulsion.  
     
     
         5 . The method for making the surface-coated reduced iron according to  claim 4 , wherein said tar emulsion comprises at least one hydrocarbon-based material selected from the group consisting of natural petroleum tar, coal tar, pitch, asphalt, liquefied coal, and residual oil from petroleum refining; a surfactant; and water.  
     
     
         6 . The method for making the surface-coated reduced iron according to  claim 5 , wherein said tar emulsion comprises 60 to 80 percent by mass of the hydrocarbon-based material, 0.1 to 1 percent by mass of the surfactant, and the balance being substantially water.  
     
     
         7 . The method for making the surface-coated reduced iron according to  claim 4 , wherein said reduced iron is produced by reduction with a gaseous reductant containing hydrogen and/or carbon monoxide or a solid reductant containing a carbonaceous material.  
     
     
         8 . The method for making the surface-coated reduced iron according to  claim 4 , wherein said coating step is performed by controlling the temperature of said reduced iron at 250° C. or less.  
     
     
         9 . A method for melting a surface-coated reduced iron having the surface coated with a tar emulsion in a smelting furnace, the surface-coated reduced iron comprising surface-coated reduced iron powder and/or chips, the method comprising the step of injecting the surface-coated reduced iron powder and/or chips into a molten iron bath formed in the smelting furnace and/or into a slag formed on the molten iron bath.  
     
     
         10 . The method for melting the surface-coated reduced iron according to  claim 9 , wherein said injecting step is performed using a gaseous medium.