US 11,685,964 B2
Method and system for recovering magnetic grains from sintered magnets or plastic magnets
Jean-Marie Le Breton, Saint Pierre de Manneville (FR); Nicolas Maat, Mont Saint Aignan (FR); and Cyril Aymonier, Begles (FR)
Assigned to CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); UNIVERSITE DE ROUEN NORMANDIE, Mont Saint-Aignan (FR); and INSTITUT NATIONAL DES SCIENCES APPLIQUEES DE ROUEN NORMANDIE, Saint-Etienne-du-Rouvray (FR)
Appl. No. 16/318,490
Filed by CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); UNIVERSITE DE ROUEN NORMANDIE, Mont saint-Aignan (FR); and INSTITUT NATIONAL DES SCIENCES APPLIQUEES DE ROUEN NORMANDIE, Saint-Etienne-du-Rouvray (FR)
PCT Filed Jul. 17, 2017, PCT No. PCT/EP2017/067985
§ 371(c)(1), (2) Date Jan. 17, 2019,
PCT Pub. No. WO2018/015331, PCT Pub. Date Jan. 25, 2018.
Claims priority of application No. 1656962 (FR), filed on Jul. 21, 2016.
Prior Publication US 2019/0226052 A1, Jul. 25, 2019
Int. Cl. C22B 7/00 (2006.01); C22B 59/00 (2006.01); H01F 41/02 (2006.01); B01D 11/02 (2006.01); B09B 3/80 (2022.01); H01F 1/057 (2006.01)
CPC C22B 7/006 (2013.01) [B01D 11/02 (2013.01); B01D 11/0207 (2013.01); B01D 11/0288 (2013.01); B09B 3/80 (2022.01); C22B 59/00 (2013.01); H01F 1/0577 (2013.01); H01F 41/0253 (2013.01); Y02P 10/20 (2015.11)] 16 Claims
OG exemplary drawing
 
1. Method for recovering magnetic grains from an object A, the object A comprising said magnetic grains and an intergranular phase between the magnetic grains, wherein the object A is a sintered magnet, said method comprising at least the following steps:
Contacting the object A with a dense fluid Fd of molar mass greater than 2 g mol−1 under conditions of temperature T1 and pressure P1 that are intended to transform the intergranular phase and to release the magnetic grains, (302), wherein the temperature and pressure conditions are less than the temperatures inducing the melting of the object A or any of the magnetic grains to be released, in order to perform a transformation of the intergranular phase,
Modifying the temperature up to a T2 temperature value and/or the pressure up to a P2 pressure value to stop the transformation of the intergranular phase, (303),
Retrieving the magnetic grains separated from the intergranular phase, said magnetic grains retaining their magnetic properties sufficient to be used for the production of new magnetic materials (304).