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Selective extraction of rare earth elements from red mud using oxalic and sulfuric acids TEXT SIZE: A A A

Red mud is an alkaline industrial solid waste discharged from alumina production via the Bayer process and can be considered a kind of potential resource of rare earth elements (REEs). Many valuable metals such as iron, aluminum, and titanium also exist in red mud. A multi-stage extraction method was proposed in this study by taking full account of the REEs' occurrence in red mud. Firstly, the pretreatments of oxalic acid leaching, roasting, and dilute hydrochloric acid leaching were employed to recover iron and enrich REEs in the residue. Subsequently, sulfuric acid leaching was used to selectively dissolve REEs into the leaching solution. Finally, the effects of sulfuric acid concentration, liquid-solid ratio, reaction temperature, and reaction time on the leaching efficiency of REEs were then investigated. The results show that the maximum extraction of the REEs reached 80 % and less than 4 % of Fe, Na, Ca, Ti and Al were extracted under the experimental conditions of 1 mol/L H2SO4, 3 h, 95 degrees C, and the liquid-solid ratio of 5:1 mL/g. The practicable approach by multi-stage extraction of acid leaching and roasting can split iron and REEs from red mud.

Publication name

 Journal Of Environmental Chemical Engineering, Volume 10, Issue 6, Article Number 108650, DOI 10.1016/j.jece.2022.108650, Published DEC 2022


 Li, Wanyan; Li, Zehai; Wang, Ning; Gu, Hannian

Corresponding author(s) 

 Gu, Hannian


 Chinese Acad Sci, Inst Geochem, Key Lab High Temp High pressure Study Earths Inter, Guiyang 550081, Peoples R China

Author(s) from IGCAS   Gu, Hannian; Li, Wanyan; Li, Zehai; Wang, Ning

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