Method for preparing recycled low-nickel magnesium alloy using magnesium scraps

Abstract

The present invention relates to a method for preparing a recycled low-nickel magnesium alloy using magnesium scraps. More particularly, the recycled magnesium alloy having a reduced nickel content can be prepared by adding Al and misch metal to molten magnesium scraps so as to form an Ni—Al-misch metal three-phase alloy or cluster thereof; and separating and removing the formed Ni—Al-misch metal three-phase alloy or the cluster thereof using gravity.

What is claimed is: 
     
         1 . A method for preparing a recycled low-nickel magnesium alloy using magnesium scraps, which comprises the steps of:
 (a) melting magnesium scraps;   (b) forming a Ni—Al-misch metal three-phase alloy by adding Al, misch metal, or Al and misch metal at the same time to the molten magnesium scraps and stirring thereof;   (c) separating a precipitate and a floating matter of the Ni—Al-misch metal three-phase alloy obtained in the step (b) by stationing thereof for 10 min to 1 hour at 700° C. to 800° C.; and   (d) casting a recycled magnesium alloy using the separated floating matter.   
     
     
         2 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 1 , wherein, in the step (b), the Al is added in a ratio of 1 to 2 parts by weight, and the misch metal is added in a ratio of 1 to 2 parts by weight, based on 100 parts by weight of the magnesium scraps. 
     
     
         3 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 2 , wherein, when the magnesium scraps do not contain Al, the Al and the misch metal are added in a weight ratio of the Al and the misch metal (Al weight/misch metal weight) of 1 to 3 in the step (b). 
     
     
         4 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 1 , wherein, when the magnesium scraps contain Al, the misch metal is added in a weight ratio of the Al contained in the magnesium scraps and the misch metal (Al weight/misch metal weight) of 1 to 3 in the step (b). 
     
     
         5 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 1 , wherein the misch metal is didymium misch metal, lanthanum-rich misch metal or Ce-rich misch metal. 
     
     
         6 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 1 , wherein, in the step (b), stirring is conducted one time, followed by stationing for 10 min to 30 min, and then conducted one more time. 
     
     
         7 . The method for preparing a recycled low-nickel magnesium alloy using magnesium scraps according to  claim 1 , wherein the Ni content of the recycled low-nickel magnesium alloy in the step (d) is 0.6 weight % or less.