Leaching of NdFeB Magent Scarp

Leaching of NdFeB magent scarp

Ho-sung Yoon*, Kyeong Woo Chung, Chul-ju Kim

Metal Recovery Dept., Korea Institute of Geoscience and Mineral Resources, Daejun 305-350, Korea

^*E-mail: hsyoon@kigam.re.kr, Tel: +82-42-868-3611

Currently, large amounts of scarp form NdFeB magnet manufacture are stockpiled owing to the lack of a cost-effective processing method. Because of the growing new market for individual rare-earth metals such as Nd and owing to the likely continuing increase in demand for permanent magnets, scrap treatment will undoubtedly become an important alternative materials source. Development of a viable method to process NdFeB scarp will aid manufacturers economically and reduce the necessity of consuming rare-earth materials.

In the present study, Nd was recovered from NdFeB scrap. To dissolution Nd and Fe, scrap was oxidizing-roasted and leached in sulfuric acid solution. Nd and Fe was separated using double-salt precipitation method by the addition of sodium sulfate to leach liquor. Optimized temperature of oxidizing-roasting was 500°C for sintering magnet and 700°C for bonded magnet. When oxidizing-roasted NdFeB magnet was treated in 2M sulfuric acid at 50°C for 2hr with the pulp density of 15%, 99.4% of Nd and 95.7% of Fe was leached and recovered.