A selective hydrometallurgical method for scandium recovery from a real red mud leachate: A comparative study

Ali Dawood Salman; Tatjána Juzsakova; Moayyed G Jalhoom; Thamer Adnan Abdullah; Phuoc-Cuong Le; Sebestyen Viktor; Endre Domokos; X Cuong Nguyen; D Duong La; Ashok K Nadda; D Duc Nguyen

doi:10.1016/j.envpol.2022.119596

A selective hydrometallurgical method for scandium recovery from a real red mud leachate: A comparative study

Environ Pollut. 2022 Sep 1:308:119596. doi: 10.1016/j.envpol.2022.119596. Epub 2022 Jun 15.

Authors

Affiliations

¹ Sustainability Solutions Research Lab, University of Pannonia, Veszprém, Hungary; Department of Chemical and Petroleum Refining Engineering, College of Oil and Gas Engineering, Basra University, Iraq.
² Sustainability Solutions Research Lab, University of Pannonia, Veszprém, Hungary.
³ Department of Production Engineering and Minerals, University of Technology Baghdad-Iraq, Iraq.
⁴ Sustainability Solutions Research Lab, University of Pannonia, Veszprém, Hungary; Chemistry Branch, Applied Sciences Department, University of Technology, Baghdad, Iraq.
⁵ The University of Danang-University of Science and Technology, 54 Nguyen Luong Bang, Danang, 550000, Viet Nam.
⁶ Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, Da Nang, 550000, Viet Nam; Faculty of Environmental and Chemical Engineering, Duy Tan University, Da Nang, 550000, Viet Nam.
⁷ Institute of Chemistry and Materials, Nghia Do, Cau Giay, Ha Noi City, Viet Nam.
⁸ Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173 234, India.
⁹ Department of Environmental Energy Engineering, Kyonggi University, South Korea; Faculty of Environmental and Food Engineering, Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, District 4, HCM City, 755414, Viet Nam. Electronic address: nguyensyduc@gmail.com.

PMID: 35716890
DOI: 10.1016/j.envpol.2022.119596

Abstract

The aim of this study was to recover Sc as the main product and Fe as a by-product from Hungarian bauxite residue/red mud (RM) waste material by solvent extraction (SX). Moreover, a new technique was developed for the selective separation of Sc and Fe from real RM leachates. The presence of high Fe content (∼38%) in RM makes it difficult to recover Sc because of the similarity of their physicochemical properties. Pyrometallurgical and hydrometallurgical methods were applied to remove the Fe prior to SX. Two protocols based on organophosphorus compounds (OPCs) were proposed, and the main extractants were evaluated: bis(2-ethylhexyl) phosphoric acid (D2EHPA/P204) and tributyl phosphate (TBP). The results showed that SX using diethyl ether and tri-n-octylamine (N₂₃₅) was efficient in extracting Fe(III) from the HCl leachate as HFeC1₄. Over 97% of Sc was extracted by D2EHPA extractant under the following conditions; 0.05 mol/L of D2EHPA concentration, A/O phase ratio of 3:1, pH 0-1, 10 min of shaking time, and a temperature of 25 °C. Sc(OH)₃ as a precipitate was efficiently obtained by stripping from the D2EHPA organic phase by 2.5 mol/L of NaOH with a stripping efficiency of 95%. In the TBP system, 99% of Sc was extracted under the following conditions: 12.5% vol of TBP, an A/O phase ratio of 3:1, 10 min of shaking time, and a temperature of 25 °C. The Sc contained in the TBP organic phase could be efficiently stripped by 1 mol/L of HCl with a stripping efficiency of 92.85%.

Keywords: D2EHPA; Diethyl ether; Scandium; Stripping; TBP.

MeSH terms

Aluminum Oxide
Ferric Compounds*
Scandium*
Waste Products

Substances

Ferric Compounds
Waste Products
Aluminum Oxide
Scandium