Method for manufacturing high purity manganese and high purity manganese

Abstract

The present invention relates to a method for manufacturing a high purity Mn, the method comprising: placing a flake-like electrolytic Mn raw material in a magnesia crucible to perform melting with the use of a vacuum induction melting furnace (VIM furnace) at a melting temperature of 1240 to 1400° C. under an inert atmosphere of 500 Torr or less; then adding calcium in a range between 0.5 and 2.0% of the weight of Mn to perform deoxidation and desulfurization; casting the resultant in an iron mold after the completion of the deoxidation and desulfurization to manufacture an ingot; then placing the Mn ingot into a magnesia crucible to perform melting with the use of a vacuum induction melting furnace (VIM furnace) at a melting temperature, which is adjusted to 1200 to 1450° C. and maintained for 10 to 60 minutes, under an inert atmosphere of 200 Torr or less; casting the resultant in an iron mold to manufacture an ingot; then placing the metal Mn ingot in an alumina crucible; reducing pressure to 0.01 Torr with a vacuum pump; and then heating to develop a sublimation and distillation reaction. Provided is a method for manufacturing a high purity metal Mn from a commercially available electrolytic Mn. In particular, an object is to obtain a high purity metal Mn in which the amount of impurities such as B, Mg, Al and Si is small.

1 . A method for manufacturing a high purity Mn, the method comprising: placing an Mn raw material in a magnesia crucible to perform melting with the use of a vacuum induction melting furnace (VIM furnace) at a melting temperature of 1240 to 1400° C. under an inert atmosphere of 500 Torr or less; then adding calcium (Ca) in a range between 0.5 and 2.0% of the weight of Mn to perform deoxidation and desulfurization; casting the resultant in an iron mold after the completion of the deoxidation and desulfurization to manufacture an ingot; then placing the Mn ingot in a magnesia crucible to perform melting with the use of a vacuum induction melting furnace (VIM furnace) at a melting temperature, which is adjusted to 1200 to 1450° C. and maintained for 10 to 60 minutes, under an inert atmosphere of 200 Torr or less; casting the resultant in an iron mold to manufacture an ingot, then placing the metal Mn ingot in an alumina crucible; reducing pressure to 0.01 to 1 Torr with a vacuum pump; and then heating to develop a sublimation and distillation reaction for obtaining a high purity Mn. 
     
     
         2 . The method for manufacturing a high purity Mn according to  claim 1 , comprising, when performing the sublimation and distillation, placing the metal Mn ingot in a cylindrical alumina crucible and vertically aligning a similarly-shaped alumina cylinder on top of the cylindrical crucible to develop a sublimation and distillation reaction so that Mn deposits inside the upper alumina cylinder. 
     
     
         3 . The method for manufacturing a high purity Mn according to  claim 2 , comprising attaching a carbon heater to the outside of a cylindrical alumina crucible into which the metal Mn ingot is placed, and performing heating. 
     
     
         4 . The method for manufacturing a high purity Mn according to  claim 3 , comprising performing sublimation and distillation purification at 1100 to 1250° C. and a sublimation and distillation rate of 20 to 184 g/h. 
     
     
         5 . The method for manufacturing a high purity Mn according to  claim 4 , comprising, when the deposited amount of sublimated/distilled Mn reaches 70% of the weight of the metal Mn ingot charged into the alumina crucible during the sublimation and distillation step, stopping the sublimation/distillation step. 
     
     
         6 .- 9 . (canceled) 
     
     
         10 . The method for manufacturing a high purity Mn according to  claim 1 , comprising attaching a carbon heater to the outside of a cylindrical alumina crucible into which the metal Mn ingot is placed, and performing heating. 
     
     
         11 . The method for manufacturing a high purity Mn according to  claim 1 , comprising performing sublimation and distillation purification at 1100 to 1250° C. and a sublimation and distillation rate of 20 to 184 g/h. 
     
     
         12 . The method for manufacturing a high purity Mn according to  claim 1 , comprising, when the deposited amount of sublimated/distilled Mn reaches 70% of the weight of the metal Mn ingot charged into the alumina crucible during the sublimation and distillation step, stopping the sublimation/distillation step.