Method and system for separating rare earth elements

A rare earth separation system for separating rare earth elements contained in a magnet wherein said magnet includes as components a first group of rare earth elements and a second group of rare earth elements, the system comprising:

• a magnet pretreatment section including:
• a magnet component oxidation heat treatment unit;
• a rare earth oxide separation unit connected with the magnet component oxidation heat treatment unit;
• and
• a powder size optimization unit connected with the rare earth oxide separation unit;
• and
• a rare earth element separation section including:
• a chlorinating agent mixing/supply unit;
• a chlorination/oxychlorination heat treatment unit;
• an atmosphere control unit;
• a waste gas disposal unit;
• and
• a chloride/oxychloride separation unit, the chlorinating agent mixing/supply unit being connected with the powder size optimization unit and the chlorination/oxychlorination heat treatment unit, the chlorination/oxychlorination heat treatment unit being connected with the chlorinating agent mixing/supply unit, the atmosphere control unit, the waste gas disposal unit and the chloride/oxychloride separation unit,
• wherein the magnet component oxidation heat treatment unit forms a powder of the magnet components and oxides the powder to prepare a magnet component oxide powder,
• wherein the rare earth oxide separation unit separates a rare earth oxide powder containing rare earth oxides including first group rare earth oxides and second group rare earth oxides from the magnet component oxide powder obtained at the magnet component oxidation heat treatment unit,
• wherein the powder size optimization unit optimizes the rare earth oxide powder so as to have a desirable powder size distribution,
• wherein the chlorinating agent mixing/supply unit mixes the rare earth oxide powder whose powder size is optimized at the powder size optimization unit with a chlorinating agent to prepare a rare earth oxide powder-chlorinating agent mixture and supplies the mixture to the chlorination/oxychlorination heat treatment unit,
• wherein the chlorination/oxychlorination heat treatment unit performs two types of chlorination/oxychlorination heat treatments:
• 1) a chlorination/selective-oxychlorination heat treatment including a chlorination heat treatment of firstly chlorinating all the rare earth oxide powder in the rare earth oxide powder-chlorinating agent mixture to obtain rare earth chlorides including first group rare earth chlorides and second group rare earth chlorides, and a selective oxychlorination heat treatment of, successively after the chlorination heat treatment, selectively oxychlorinates only the second group rare earth chlorides to prepare a first group rare earth chlorides-second group rare earth oxychlorides mixture;
• or
• 2) a simultaneous selective-chlorination/selective-oxychlorination heat treatment of simultaneously forming the first group rare earth chlorides-second group rare earth oxychlorides from the rare earth oxide powder-chlorinating agent mixture all at once,
• wherein the chlorination heat treatment in the chlorination/selective-oxychlorination heat treatment is performed at a temperature at which all of the rare earth oxide powder can be chlorinated to form the rare earth chlorides and lower than vaporization temperatures of the rare earth chlorides in a non-oxidizing atmosphere and the selective-oxychlorination heat treatment in the chlorination/selective-oxychlorination heat treatment is performed at an optimal temperature in an oxidizing atmosphere,
• wherein the simultaneous selective-chlorination/selective-oxychlorination heat treatment is performed at a temperature at which only the first group rare earth oxides can be chlorinated and only the second group rare earth oxides can be oxychlorinated,
• wherein the atmosphere control unit controls the non-oxidizing atmosphere used in the chlorinating heat treatment, the oxidizing atmosphere used in the selective-oxychlorinating heat treatment, and the non-oxidizing atmosphere used in the simultaneous selective-chlorination/selective-oxychlorination heat treatment,
• wherein the waste gas disposal unit disposes ammonia gas and hydrogen chloride gas generated by the chlorination heat treatment, chlorine gas generated by the selective-oxychlorination heat treatment, and ammonia gas generated by the simultaneous selective-chlorination/selective-oxychlorination heat treatment,
• and wherein the chloride/oxychloride separation unit firstly introduces the first group rare earth chlorides-second group rare earth oxychlorides mixture in a solvent in order to selectively dissolve the first group rare earth chlorides in the solvent and leave the second group rare earth oxychlorides undissolved in solid phase form;
• and then solid-liquid separates the solvent in which the first group rare earth chlorides are dissolved and the second group rare earth oxychlorides are in solid phase form.

A rare earth separation system for separating rare earth elements contained in a magnet wherein said magnet includes as components a first group of rare earth elements, a second group of rare earth elements and boron, the system comprising:

• a magnet pretreatment section including:
• a magnet component oxidation heat treatment unit;
• a rare earth oxide separation unit;
• a boron reduction unit;
• a powder size optimization unit;
• and
• an additional oxidation heat treatment unit, the rare earth oxide separation unit being connected with the magnet component oxidation heat treatment unit and the boron reduction unit, the powder size optimization unit being connected with the boron reduction unit and the additional oxidation heat treatment unit;
• and
• a rare earth element separation section including:
• a chlorinating agent mixing/supply unit;
• a chlorination/oxychlorination heat treatment unit;
• an atmosphere control unit;
• a waste gas disposal unit;
• and
• a chloride/oxychloride separation unit, the chlorinating agent mixing/supply unit being connected with the additional oxidation heat treatment unit and the chlorination/oxychlorination heat treatment unit, the chlorination/oxychlorination heat treatment unit being connected with the atmosphere control unit, the waste gas disposal unit and the chloride/oxychloride separation unit,
• wherein the magnet component oxidation heat treatment unit forms a powder of the magnet components and oxides the powder to prepare a magnet component oxide powder,
• wherein the rare earth oxide separation unit separates a rare earth oxide powder containing rare earth oxides including first group rare earth oxides and second group rare earth oxides from the magnet component oxide powder obtained at the magnet component oxidation heat treatment unit,
• wherein the boron reduction unit reduces boron remaining in the rare earth oxide powder separated at the rare earth oxide separation unit,
• wherein the powder size optimization unit optimizes the rare earth oxide powder so as to have a desirable powder size distribution,
• wherein the additional oxidation heat treatment unit further and completely oxidizes the rare earth oxide powder whose powder size is optimized at the powder size optimization unit,
• wherein the chlorinating agent mixing/supply unit mixes the rare earth oxide powder that is further oxidized at the additional oxidation heat treatment unit with a chlorinating agent to prepare a rare earth oxide powder-chlorinating agent mixture and supplies the mixture to the chlorination/oxychlorination heat treatment unit,
• wherein the chlorination/oxychlorination heat treatment unit performs two types of chlorination/oxychlorination heat treatments:
• 1) a chlorination/selective-oxychlorination heat treatment including a chlorination heat treatment of first chlorinating all the rare earth oxide powder in the rare earth oxide powder-chlorinating agent mixture to obtain rare earth chlorides including first group rare earth chlorides and second group rare earth chlorides, and a selective oxychlorination heat treatment of, successively after the chlorination heat treatment, selectively oxychlorinating only the second group rare earth chlorides to prepare a first group rare earth chlorides-second group rare earth oxychlorides mixture;
• or
• 2) a simultaneous selective-chlorination/selective-oxychlorination heat treatment of simultaneously forming the first group rare earth chlorides-second group rare earth oxychlorides from the rare earth oxide powder-chlorinating agent mixture all at once,
• wherein the chlorination heat treatment in the chlorination/selective-oxychlorination heat treatment is performed at a temperature at which all of the rare earth oxide powder can be chlorinated to form the rare earth chlorides and lower than vaporization temperatures of the rare earth chlorides in a non-oxidizing atmosphere and the selective-oxychlorination heat treatment in the chlorination/selective-oxychlorination heat treatment is performed at an optimal temperature in an oxidizing atmosphere,
• wherein the simultaneous selective-chlorination/selective-oxychlorination heat treatment is performed at a temperature at which only the first group rare earth oxides can be chlorinated and only the second group rare earth oxides can be oxychlorinated,
• wherein the atmosphere control unit controls the non-oxidizing atmosphere used in the chlorinating heat treatment, the oxidizing atmosphere used in the selective-oxychlorinating heat treatment, and the non-oxidizing atmosphere used in the simultaneous selective-chlorination/selective-oxychlorination heat treatment,
• wherein the waste gas disposal unit disposes ammonia gas and hydrogen chloride gas generated by the chlorination heat treatment, chlorine gas generated by the selective-oxychlorination heat treatment, and ammonia gas generated by the simultaneous selective-chlorination/selective-oxychlorination heat treatment,
• and wherein the chloride/oxychloride separation unit first introduces the first group rare earth chlorides-second group rare earth oxychlorides mixture in a solvent in order to selectively dissolve the first group rare earth chlorides in the solvent and leave the second group rare earth oxychlorides undissolved in solid phase form;
• and then solid-liquid separates the solvent in which the first group rare earth chlorides are dissolved and the second group rare earth oxychlorides are in solid phase form.