Operation method of moving hearth furnace

Abstract

An operation method of a moving hearth furnace, in which a reduced metal is obtained by reducing by heating a metal oxide loaded into the moving hearth furnace, includes the step of supplying and burning a fuel including combustible wastes as a heat source for the operation. According to the operation method of a moving hearth furnace, the resources can be used effectively and costs can be reduced by using industrial wastes as a fuel.

We claim:  
     
         1 . An operation method of a moving hearth furnace, in which a reduced metal is obtained by loading a metal oxide into the moving hearth furnace and reducing the metal oxide by heating, the method comprising the steps of: 
 supplying a fuel including combustible wastes as a heat source into the moving hearth furnace and burning the fuel.    
     
     
         2 . The operation method of a moving hearth furnace, according to  claim 1 , wherein a liquid is used as the fuel, and one part of the fuel or the entire fuel is sprayed into the moving hearth furnace.  
     
     
         3 . The operation method of a moving hearth furnace, according to  claim 2 , wherein the diameter of each orifice of a spray for spraying the fuel is set to be not smaller than 1.1 mm.  
     
     
         4 . The operation method of a moving hearth furnace, according to  claim 2 , wherein the temperature in the furnace is set to be not lower than 150° C.  
     
     
         5 . The operation method of a moving hearth furnace, according to  claim 2 , wherein the fuel is ignited by a pilot burner which is disposed in the vicinity of a position at which the fuel is sprayed.  
     
     
         6 . The operation method of a moving hearth furnace, according to  claim 5 , wherein the temperature in the furnace is set to be not lower than 150° C.  
     
     
         7 . The operation method of a moving hearth furnace, according to  claim 1 , wherein a liquid is used as the fuel, and one part of the fuel or the entire fuel is poured into the moving hearth furnace.  
     
     
         8 . The operation method of a moving hearth furnace, according to  claim 7 , wherein the temperature in the furnace is set to be not lower than 1100° C. and the residence time of the fuel in the furnace is set to be not shorter than three minutes.  
     
     
         9 . The operation method of a moving hearth furnace, according to  claim 1 , wherein one part of the fuel or the entire fuel is mixed with the metal oxide, and the mixture is loaded into the moving hearth furnace.  
     
     
         10 . The operation method of a moving hearth furnace, according to  claim 9 , wherein the temperature in the furnace is set to be not lower than 1100° C. and the residence time of the fuel in the furnace is set to be not shorter than three minutes.  
     
     
         11 . The operation method of a moving hearth furnace, according to  claim 1 , wherein further comprising the step of including an alkali metal to the fuel.  
     
     
         12 . The operation method of a moving hearth furnace, according to  claim 11 , wherein the amount of the alkali metal to be included in the fuel is controlled in accordance with the amount of S and Cl generated in the furnace during the reduction by heating.