Recycling of NdFeB magnets using nitration, calcination and water leaching for REE recovery

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• 作者：Mehmet Ali Recai Ö ; nal^a ; ^{mehmetalirecai.onal@mtm.kuleuven.be} ; Emir Aktan^c ; Chenna Rao Borra^b ; Bart Blanpain^a ; Tom Van Gerven^b ; Muxing Guo^a
• 关键词：Recycling ; NdFeB magnets ; Nitration ; Calcination ; Water leaching
• 刊名：Hydrometallurgy
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：167
• 期：Complete
• 页码：115-123
• 全文大小：2103 K
• 卷排序：167

文摘

A potentially environmentally-friendly and cost-effective flowsheet was developed that is adjustable to all REE magnets. Concentrated nitric acid was mixed with up to < 1000 µm magnet powder to completely form a nitrate mixture in 1 h at 25 °C. Fe-nitrate completely decomposed by calcination at 200 °C for 1 h to insoluble forms without any REE-nitrate decomposition. After leaching of the calcine at 25 °C for 1 h in water, > 95 % REE and < 1 % Fe extractions were achieved. The majority of the consumed acid can be theoretically recycled by simple condensation of the by-product gases. The goethite-hematite residue can be further decomposed to only hematite as a potentially more useful by-product.