NdFeB The selective leaching method of only the rare earth elements in the NdFeB magnet scrap

• Main Authors: JIN, JONG HWAN, KIM, SANG KYUNG, LEE, SEUNG HO, LEE, KWANG YUL, CHANG, KON HEE
• Format: Patent
• Language: English; Korean
• Published: 04.10.2016
• Subjects: CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The present invention relates to a method of selectively dissolving only rare earth elements in NdFeB magnet scrap. Scraps cut and ground by a manufacturing process of an NdFeB magnet spontaneously ignites a fire on fine powder during a combustion of organic matters. The product scrap is formed with individual elements while collapsing a structure of being combined with the NdFeB magnet by spontaneously igniting fire after finely pulverizing the product scrap after oxidizing the scrap at 1000C. The present invention selectively dissolves only rare earth elements by heating oxide up to 1000C so that oxidized -Fe_2O_3 becomes -Fe_2O_3 which is not dissolved by acid after finely pulverizing the oxide, generated by a spontaneous ignition reaction, again; and by heating oxidized scrap treated at high temperatures into dilute nitric acid at a temperature equal to or greater than 50C. 본 발명은 NdFeB자석 스크랩에서 희토류원소만을 선택적으로 용해하는 방법에 관한 것으로, NdFeB자석의 제조공정 중에 발생하는 절삭 및 연마스크랩은 유기물을 연소하면서 미세분말을 자연발화 반응을 시키고, 제품스크랩은 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 않은 α-FeO형태로 되게끔 1000℃로 가열하고, 고온으로 처리된 산화스크랩을 묽은 질산으로 50℃ 이상에서 가열하여 희토류원소만 선택적으로 용해한다.