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 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 in a skull melting furnace; reducing pressure to 10 −5 Torr or less with a vacuum pump; starting heating and keeping the Mn in a molten state for 10 to 60 minutes; and then ending the melting reaction for obtaining a high purity metal Mn. 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 a 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 skull melting furnace; reducing pressure to 10 −5  Torr or less with a vacuum pump; starting heating and keeping the Mn in a molten state for 10 to 60 minutes; and then ending the melting reaction for obtaining a high purity Mn. 
     
     
         2 . A high purity Mn refined via vacuum induction melting (VIM) and skull melting, wherein a total amount of B, Mg, Al, Si, S, Ca, Cr, Fe, and Ni as impurity elements is 50 ppm or less, and the purity excluding gas components is 4N5 (99.995%) or higher. 
     
     
         3 . A high purity Mn refined via vacuum induction melting (VIM) and skull melting according to  claim 2 , wherein contents of oxygen (O) and nitrogen (N) as gas components are each less than 10 ppm. 
     
     
         4 . A high purity Mn containing B, Mg, Al, Si, S, Ca, Cr, Fe, and Ni as impurity elements, wherein a total amount of B, Mg, Al, Si, S, Ca, Cr, Fe, and Ni as impurity elements is 50 ppm or less, and the purity excluding gas components is 4N5 (99.995%) or higher. 
     
     
         5 . A high purity Mn according to  claim 4 , wherein contents of oxygen (O) and nitrogen (N) as gas components are each less than 10 ppm.