Methods for manganese removal of cast iron

Abstract

The present invention does not require a demanganese agent such as a sulfide or a combustible gas in the removal of manganese of cast iron. The method for removing manganese of cast iron according to the present invention is implemented by performing the removal of a manganese component by allowing a furnace to be in an oxygen atmosphere, and by blowing air into a molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. Alternatively, the method for removing manganese of cast iron according to the present invention is implemented by performing the removal of the manganese component by allowing the furnace to be in an oxygen atmosphere and by stirring the molten cast iron in the furnace, while the carbon component in the molten cast iron is being maintained at an approximately constant amount.

1 . A method for removing manganese of cast iron, wherein the removal of a manganese component is performed by allowing a furnace to be in an oxygen atmosphere by introducing oxygen gas into the furnace, and by blowing air into a molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. 
     
     
         2 . A method for removing manganese of cast iron, wherein the removal of a manganese component is performed by allowing a furnace to be in an oxygen atmosphere by introducing oxygen gas into the furnace, and by stirring a molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. 
     
     
         3 . The method for removing manganese of cast iron according to  claim 2 , wherein the removal of the manganese component is performed while the amount of oxygen fed into the furnace or/and the stirring speed of the molten cast iron in the furnace are being regulated. 
     
     
         4 . The method for removing manganese of cast iron according to  claim 1 , wherein the removal of manganese is performed while the ratio between the removal rate of a silicon component and the removal rate of the manganese component is being maintained at an approximately constant value. 
     
     
         5 . The method for removing manganese of cast iron according to  claim 1 , wherein the removal of manganese is performed while the decrease of a silicon component is being suppressed. 
     
     
         6 . The method for removing manganese of cast iron according to  claim 1 , wherein the removal of manganese is performed while the temperature of the molten cast iron is being maintained at an approximately constant temperature. 
     
     
         7 . The method for removing manganese of cast iron according to  claim 1 , wherein the temperature of the molten cast iron is 1400° C. to 1200° C. 
     
     
         8 . A method for removing a metal component of cast iron, wherein the removal of a manganese component as well as the removal of the metal component such as chromium, titanium, aluminum, boron or zinc is performed by allowing a furnace to be in an oxygen atmosphere by introducing oxygen gas into the furnace, and by blowing air into a molten cast iron in the furnace, or by allowing the furnace to be in an oxygen atmosphere, and by stirring the molten cast iron in the furnace, while a carbon component in the molten cast iron is being maintained at an approximately constant amount. 
     
     
         9 . The method for removing manganese of cast iron according to  claim 2 , wherein the removal of manganese is performed while the ratio between the removal rate of a silicon component and the removal rate of the manganese component is being maintained at an approximately constant value. 
     
     
         10 . The method for removing manganese of cast iron according to  claim 2 , wherein the removal of manganese is performed while the decrease of a silicon component is being suppressed. 
     
     
         11 . The method for removing manganese of cast iron according to  claim 2 , wherein the removal of manganese is performed while the temperature of the molten cast iron is being maintained at an approximately constant temperature. 
     
     
         12 . The method for removing manganese of cast iron according to  claim 2 , wherein the temperature of the molten cast iron is 1400° C. to 1200° C.