利用高溫 - 濕法冶金工藝和支撐式液態薄膜從廢永磁體中回收稀土元素

Recovery of Rare Earth Elements (REEs) from Waste Permanent Magnets by Pyro-Hydrometallurgy Process and Supported Liquid Membrane

倪川森(Achmad Chusnun Niam)

指導教授 ： 游勝傑 ； 王雅玢

中原大學/工學院/土木工程研究所/博士(2020年)

https://doi.org/10.6840/cycu202000865

摘要

在世界需求不斷增加的電器和電子產品中，永久性磁鐵（PM）扮演著重要的角色，為了減少廢棄金屬的產生及需求的不足，回收再利用是目前行業主流的方式，對珍貴的稀土元素而言，有效率的回收再利用更加重要。由於濕法冶金技術操作簡單且可行性較佳，因此本研究亦使用此技術來回收廢磁鐵。本研究先使用Taguchi方法針對滲出液、溶劑萃取及沉澱過程進行影響參數分析，對於稀土元素（REE）溶出程序之最佳參數組合為：在未改質之WPM，加入5M HCl，於溫度338K加熱24小時，固液比保持為2％，攪拌速度800 rpm及粒徑0.250 mm。其中酸性溶劑種類為影響最大之參數，稀土元素溶出所佔之百分比分別為Nd 78％，Pr 83％和Dy 76％。此外，在溶劑萃取測試中，用1M D2EHPA 稀釋於isopar-L並保持在pH 2的條件下，稀土元素（REE）溶出之最佳結果，分別為Dy 81.55％、Nd 83.5％和Pr 87.93％。在HFSLM研究中，元素釹、鏑、鐠在90分鐘時的最佳萃取率分別為58.62％，98.46及85.59％，回收率分別為63.13％，15.21％及56.29％。 在本研究中，利用HFSLM方法可以在35分鐘內成功的回收90.82％的釹；也進一步證實HFSLM系統在實驗室，可以從工業廢棄物中，成功回收稀土元素；研究亦針對稀土氧化物的特徵進行分析。

關鍵字

溶出 ； 釹 ； 回收 ； 溶劑萃取 ； 支撐式液態薄膜

並列摘要

Permanent magnets (PMs) play a significant role in electrical and electronic products and therefore their demand in countries is constantly increasing. Recycling is the main technology for metal recovery from many sources and is an approach to reduce waste generation and generates revenue to satisfy demands metals, particularly rare earth elements. The hydrometallurgical method is beneficial for waste magnet recycling as they are easy to operate and feasible. Leaching studies by Taguchi method, solvent extraction, and precipitation process is reported in this study. The optimum parameters of leaching treatment was achieved by unmodified WPMs, 5M of HCl, 338 K temperature, 24 hours, 2% S/L ratio, 800 rpm stirring speed, 0.250 mm particle size. The most influential factor is acid type with the percentage of contribution for leaching of rare earth elements 78% (Nd), 83% (Pr), and 76% (Dy). 1M D2EHPA diluted in isopar-L at pH 2 present an optimum parameter for REEs extraction 81.55%, 83.5% and 87.93% of dysprosium, neodymium, and praseodymium, respectively. The optimum extraction percentage achieved at 90 minutes for neodymium, dysprosium, and praseodymium was 58.62%, 98.46, and 85.59%, as well as for the recovery 63.13%, 15.21%, and 56.29%, respectively from WPMs leach liquor by HFSLM method. In addition, HFSLM method was successfully recovered 90.82% of neodymium from neodymium precipitated within 35 minutes. HFSLM system was successfully applied in the lab-scale for recycling of REEs from industrial waste materials. Moreover, REE oxides characterization was investigated in this study.

並列關鍵字

Leaching ； neodymium ； recovery ； solvent extraction ； supported liquid membrane.

參考文獻

[1] R. Eggert, Wadia, C., Anderson, C., Bauer, D., Fields, F., Meinert, L., Taylor, P.,, "Rare Earths: Market Disruption, Innovation, and Global Supply Chains," Annual Review of Environment and Resources, vol. 41, no. 1, pp. 199-222, 2016/11/01 2016, doi: 10.1146/annurev-environ-110615-085700.

[2] R. Kleijn and E. van der Voet, "Resource constraints in a hydrogen economy based on renewable energy sources: An exploration," Renewable and Sustainable Energy Reviews, vol. 14, no. 9, pp. 2784-2795, 2010, doi: 10.1016/j.rser.2010.07.066.

[3] B. Sprecher et al., "Life cycle inventory of the production of rare earths and the subsequent production of NdFeB rare earth permanent magnets," Environ Sci Technol, vol. 48, no. 7, pp. 3951-8, Apr 1 2014, doi: 10.1021/es404596q.

[4] P. K. Parhi, "Supported Liquid Membrane Principle and Its Practices: A Short Review," Journal of Chemistry, vol. 2013, pp. 1-11, 2013, doi: 10.1155/2013/618236.

[5] M. K. Sinha et al., "Recovery of value added products of Sm and Co from waste SmCo magnet by hydrometallurgical route," Separation and Purification Technology, vol. 179, pp. 1-12, 2017, doi: 10.1016/j.seppur.2017.01.056.