{"title":"Efficient recovery of rare earth elements from ion-adsorption rare earth tailings: Based on the addition of pyrite calcination modification","authors":"","doi":"10.1016/j.seppur.2024.129767","DOIUrl":null,"url":null,"abstract":"<div><div>Rare earth tailings constitute a significant amount of solid waste that remains after industrial (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> leaching and typically contain rare earth elements (REEs), primarily Ce. This study aimed to fully recover REEs from rare earth tailings by calcination with pyrite under both air and N<sub>2</sub> atmospheres, followed by dilute H<sub>2</sub>SO<sub>4</sub> leaching or bioleaching. The results of XRD, SEM-EDS, TIMA, SEM-BSE, XPS, and ICP-MS analyses indicated that Ce and Mn were mainly present in the form of CeO<sub>2</sub> and MnO<sub>2</sub>, respectively, whereas Fe existed in both Fe<sub>2</sub>O<sub>3</sub> and Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> forms. Leaching experiments with dilute H<sub>2</sub>SO<sub>4</sub> demonstrated that the co-calcination of rare earth tailings with pyrite significantly enhanced the recovery of REEs. Notably, calcination in air resulted in a significantly higher extraction rate of Ce (95.55 %) than that in N<sub>2</sub> (83.82 %). This difference was attributed to the presence of O<sub>2</sub>, which promoted the oxidation of pyrite and facilitated the reduction of Ce(IV) to Ce(III). In contrast, incomplete oxidation of pyrite occurred in the N<sub>2</sub> atmosphere, leading to a high residual Ce(IV) content in the tailings that could not be leached by the dilute acid. Subsequently, sufficient recovery of Ce (97.52 %) from the tailings calcined in the N<sub>2</sub> atmosphere was achieved by bioleaching using <em>Acidithiobacillus ferrooxidans</em> and pyrite. Thus, this study provides theoretical support for the efficient recovery of REEs from mining tailings or secondary sources containing CeO<sub>2</sub>.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":null,"pages":null},"PeriodicalIF":8.1000,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Separation and Purification Technology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1383586624035068","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Rare earth tailings constitute a significant amount of solid waste that remains after industrial (NH4)2SO4 leaching and typically contain rare earth elements (REEs), primarily Ce. This study aimed to fully recover REEs from rare earth tailings by calcination with pyrite under both air and N2 atmospheres, followed by dilute H2SO4 leaching or bioleaching. The results of XRD, SEM-EDS, TIMA, SEM-BSE, XPS, and ICP-MS analyses indicated that Ce and Mn were mainly present in the form of CeO2 and MnO2, respectively, whereas Fe existed in both Fe2O3 and Fe2(SO4)3 forms. Leaching experiments with dilute H2SO4 demonstrated that the co-calcination of rare earth tailings with pyrite significantly enhanced the recovery of REEs. Notably, calcination in air resulted in a significantly higher extraction rate of Ce (95.55 %) than that in N2 (83.82 %). This difference was attributed to the presence of O2, which promoted the oxidation of pyrite and facilitated the reduction of Ce(IV) to Ce(III). In contrast, incomplete oxidation of pyrite occurred in the N2 atmosphere, leading to a high residual Ce(IV) content in the tailings that could not be leached by the dilute acid. Subsequently, sufficient recovery of Ce (97.52 %) from the tailings calcined in the N2 atmosphere was achieved by bioleaching using Acidithiobacillus ferrooxidans and pyrite. Thus, this study provides theoretical support for the efficient recovery of REEs from mining tailings or secondary sources containing CeO2.
期刊介绍:
Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.