A research team led by Jang Pok Nam, a section head at the Faculty of Metal Engineering, has established an Nd-Fe alloy production process for rare earth magnet by using rare earth resources in our country.
Because of its great activity and its good properties, rare earth metal is widely used in various fields including the metallurgical and electronic automation industries and the field of its application is being widened more and more.
Especially, Nd-Fe-B system rare earth magnets have the best characteristics of all magnets that have been developed so far, and their application in various industrial fields brings great economic profits.
Neodymium-iron alloy is a main material for production of Nd-Fe-B magnets.
The research team has established a system of producing Nd-Fe by rare earth fluoride-oxide molten salt electrolysis.
Compared to chloride electrolysis process, fluoride-oxide electrolysis process has good adaptability to raw materials and it enables production of various rare earth metals and alloys.
Fluoride-oxide electrolysis, a method by which the composition of electrolytes is not changed and neodymium oxide is periodically supplemented, makes possible continuous production without any limits of electrolysis time.
The Nd-Fe production process consists of electrolyte manufacturing process and electrolytic production process.
In the electrolyte manufacturing process, anhydrous neodymium fluoride is produced from neodymium chloride.
In the electrolytic production process, Nd-Fe alloy is produced in a graphite crucible with a pure iron electrode as a cathode and a carbon electrode as an anode.
Under electrolytic conditions, the current efficiency is 68~69%, the direct yield of neodymium is 92%, and the power consumption is 13.7 kW•h/kg.
The content of neodymium in the neodymium iron alloys produced is very high with more than 85%, and the non-rare earth content is very low, so that the alloy can be used for the production of magnets directly without undergoing a refining process.
© 2021 KumChaek University of Technology