Leaching of Light Rare Earth Elements from Sichuan Bastnaesite: A Facile Process to Leach Trivalent Rare Earth Elements Selectively from Tetravalent Cerium

• Published in: JOM (1989) Vol. 69; no. 10; pp. 1976 - 1981
• Main Authors: Shen, Yueyue, Jiang, Ying, Qiu, Xianying, Zhao, Shilin
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2017; Springer Nature B.V
• Subjects: Bastnasite; Caustic soda; Cerium; Chemistry/Food Science; Earth Sciences; Efficiency; Engineering; Environment; Experiments; Fluorides; Hydrochloric acid; Leaching; Materials science; Nitric acid; Oxidation; Particle size; Physics; Rare earth elements; Scanning electron microscopy; Solvent extraction processes; Sulfuric acid; Temperature; Trace elements
• ISSN: 1047-4838; 1543-1851
• DOI: 10.1007/s11837-017-2458-8

The effects of the nitric acid concentration, leaching time, leaching temperature, and solid-to-liquid ratio on leaching efficiency were examined. From those results, a facile process for the selective leaching of trivalent rare earth elements (RE(III)) from tetravalent cerium (Ce(IV)) was proposed. The roasted bastnaesite was used to leach 34.87% of RE(III) and 2.15% of Ce(IV) at 60°C for 0.5 h with an acid concentration of 0.5 mol/L. This selective leaching process can be described by the shrinking-core model that follows the kinetic model 1 − 2/3 α  − (1 −  α ) 2/3 . Subsequently, the leached slag was hydrothermally treated and followed by thorough leaching with 4.0-mol/L nitric acid. Furthermore, the specific surface area of the final leached slag is 57.7 m 2 /g, which is approximately 650 times higher than that of raw ore. Finally, selective leaching of RE(III) (>90%) was achieved without using an organic solvent for extraction, whereas lower value Ce(IV)was presented in the leached slag (>92%).