Recovery of Neodymium as (Na, Nd)(SO4)2 from the Ferrous Fraction of a General WEEE Shredder Stream

Abstract

Neodymium is a critical element used in many high-tech applications. However, despite this, the EU is entirely dependent on China for its Nd supply. This has driven the EU to develop recycling strategies to recover its Nd from end-of-life (EoL) products and wastes, and establish a domestic supply. This paper proposes a process to recycle Nd from NdFeB magnet particles present in the ferrous fraction of shredded ''Waste Electrical and Electronic Equipment'' (WEEE), after physical upgrading. This WEEE fraction represents a waste stream that has not been previously considered a source of Nd. A threestep process was developed. First, the upgraded ferrous WEEE fraction is oxidized by means of water corrosion. Second, the oxidized WEEE is leached with diluted H 2 SO 4 to selectively extract Nd and other nonferrous elements. And finally, the leach liquor is treated with Na 2 SO 4 to precipitate the Nd as its double sulfate (Nd, Na)(SO 4 ) 2 . The oxidation process oxidizes 93% of the metallic iron to Fe(OH) 3 , leaving 7% of the iron unoxidized. The leaching process dissolves between 70 and 99% of the Nd, depending on the temperature and liquid/solid ratio (L/S); this is accompanied by an iron coextraction between 9 and 20%. The precipitation recovers 92% of the leached Nd. The purity of the obtained precipitates is dependent on the pH at which the precipitation takes place. A pH below 0.5 is required to prevent Fe contamination, and a pH below 0 reduces the Ca contamination to below 1 wt%. The developed process provides an effective and low-cost method to recycle Nd from a shredded WEEE stream with an overall Nd recovery of over 90%.Journal of Sustainable Metallurgy (2018) 4:276-287 https://doi.org/10.1007/s40831-018-0165-5( 0123456789().,-volV) (0123456789().,-volV) Journal of Sustainable Metallurgy (2018) 4:276-287 277

Recovery of Rare Earth Elements from Spent NdFeB-Magnets: Separation of Iron through Reductive Smelting of the Oxidized Material (Second Part)

“…The extraction of Nd from waste Nd-Fe-B alloys was studied by the glass slag method [5], microwave-assisted carbothermic reduction [6], and through the interaction of rare earth element neodymium, iron, and arsenic at 900 • C [7] confirming that separation of iron is possible during the pyrometallurgical method. In comparison to the pyrometallurgical method, the hydrometallurgical method offers a separation of iron during precipitation and acidic baking [8][9][10][11][12][13][14][15][16][17][18][19][20]. Orefice [21] mentioned selective roasting of Nd-Fe-B permanent magnets as an important pretreatment step for intensified leaching with an ionic liquid.…”

Novel neodymium complex on MCM‐41 magnetic nanocomposite as a practical, selective, and returnable nanocatalyst in the synthesis of tetrazoles with antifungal properties in agricultural

“…Also, a broad peak of 2θ value about 20-30 position is related to the amorphous SiO 2 . [21,58] This peak is not seen in the XRD pattern of MCM-41 MNC, because after modifying the MCM-41 MNC surface, an amorphous layer of silica is created, which leads to the apparent of a broad peak of 2θ in the region of 20-30.…”

Hydrometallurgical Recovery of Rare Earth Elements from Mine Tailings and WEEE

“…Direct Hydrometallurgical Approach Figure 2 shows the proposed flowsheet to recycle REEcontaining WEEE [21], from the shredder to the metallic REE alloy. The process steps developed and described in this study are highlighted by the dashed box.…”