Leaching Behavior of Mixed Rare Earth Concentrates after Decomposition by Microwave Heating

The leaching behaviors of rare earth elements (REEs) in HCl solution have been investigated for mixed rare earth concentrates after decomposition by microwave heating. The effects of HCl concentration, temperature, reaction time, liquid–solid ratio (L/S), and stirring speed were explored. The result...

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Bibliographic Details
Published in:JOM (1989) 2022-08, Vol.74 (8), p.3049-3058
Main Authors: Huang, Yu-kun, Guo, Hao-jie, Wang, Da-song, Chen, Peng-xu, Cao, Yi-jun, Peng, Wei-jun, Liu, Jiang
Format: Article
Language:English
Subjects:
Chemical precipitation
Chemistry/Food Science
Crystallization
Decomposition
Decomposition reactions
Diffusion layers
Earth Sciences
Energy consumption
Engineering
Environment
Fluorides
Heat
Heating
Leaching
Metallurgy
Microwave heating
Mineralogy
Phase transitions
Physics
Progress on Recovery of Critical Raw Materials
Radiation
Rare earth elements
Rare earth phosphates
Reaction time
Scanning electron microscopy
Trace elements
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Summary:The leaching behaviors of rare earth elements (REEs) in HCl solution have been investigated for mixed rare earth concentrates after decomposition by microwave heating. The effects of HCl concentration, temperature, reaction time, liquid–solid ratio (L/S), and stirring speed were explored. The results showed that temperature, L/S, and HCl concentration mainly influenced the leaching efficiencies of the REEs, and that the leaching ratio of the REEs in the microwave heating process (88.31%) was 16.49% higher than that (71.82%) in the conventional heating process. X-ray diffraction and scanning electron microscopy analysis results of leaching residues suggest that rare earth and phosphate ions in the solution reform the tiny insoluble needle-like solid particles by precipitation and crystallization. The apparent activation energy was calculated as 27.01 kJ/mol from the leaching kinetics study, indicating that the leaching process was affected by the interfacial transfer and diffusion of reactants across the rare earth phosphate product layer.
ISSN:1047-4838
1543-1851
DOI:10.1007/s11837-022-05266-4