NdFeB The Selective Dissolving Method of Rare Earth Elements by Hydrochloric acid in the Scrapped permanent magnet NdFeB

• Main Authors: JIN, JONG HWAN, KIM, SANG KYUNG, LEE, SEUNG HO, LEE, KWANG YUL, CHANG, KON HEE
• Format: Patent
• Language: English; Korean
• Published: 24.05.2017
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; FERROUS OR NON-FERROUS ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The present invention relates to a method of selectively dissolving a rare earth element by hydrochloric acid in NdFeB magnet scrap. Cutting and polishing scrap produced during a manufacturing process of an NdFeB magnet causes a spontaneous combustion reaction on fine powder while an organic matter is combusted. Product scrap is finely crushed after the product scrap is oxidized at 900-1,000C; and then a spontaneous combustion reaction is caused on the product scrap to allow a binding structure of the NdFeB magnet to collapse and make oxide of an individual element. After finely crushing the oxide created by the spontaneous combustion reaction again, the oxide is heated at 900-1,000C to allow oxidized -Fe_2O_3 to become -Fe_2O_3 which do not dissolve in acid. Oxidized scrap treated at high temperatures is heated at 80-90C by thin acid to selectively dissolve only a rare earth element. NdFeB자석 스크랩에서 희토류원소만을 염산으로 선택적으로 용해하는 방법에 관한 것으로, NdFeB자석의 제조공정 중에 발생하는 절삭 및 연마스크랩은 유기물을 연소하면서 미세분말을 자연발화 반응을 시키고, 제품스크랩은 900℃∼1000℃로 산화시킨 다음에 미세하게 파쇄한 후에 자연발화 반응을 시켜 NdFeB자석의 결합구조를 붕괴시키면서 개별원소의 산화물로 만든다. 자연발화 반응으로 생성된 산화물을 다시 미세하게 분쇄한 후에 산화된 γ-FeO가 산에 용해되지 않는 α-FeO형태로 되게끔 900℃∼1000℃에서 가열하고, 고온으로 처리된 산화스크랩을 묽은 염산으로 80℃∼90℃로 가열하여 희토류원소만을 선택적으로 용해한다.