Enhancing Magnetic Contrast through Mineral Phase Transformation: Flotation Performance of Bastnaesite-Transformed...

Area of Science:

• Metallurgy and Materials Science
• Mineral Processing
• Chemical Engineering

Background:

• Resource depletion necessitates efficient utilization of low-grade rare-earth ores.
• Conventional beneficiation methods struggle with effective recovery of valuable components from complex ores.

Purpose of the Study:

• To develop and evaluate a mineral phase transformation (MPT) strategy for enhanced separation of bastnaesite and iron minerals.
• To investigate the impact of MPT on magnetic separation and subsequent flotation of rare-earth elements (REEs).

Main Methods:

• Mineral phase transformation (MPT) via roasting of bastnaesite and polymetallic ores.
• Magnetic separation and flotation experiments.
• Analytical tests (e.g., phase analysis, surface property examination) to characterize MPT products.

Main Results:

• MPT significantly amplified magnetic contrast between bastnaesite and iron minerals, improving magnetic separation efficiency for iron.
• Rare-earth elements in MPT products were effectively recovered using benzohydroxamic acid (BHA) flotation.
• For Bayan Obo low-grade polymetallic ore (BOLPO), magnetic separation achieved 61.69% iron grade and 84.24% recovery; flotation yielded 60.46% REO grade and 50.78% recovery.
• MPT induced changes in bastnaesite, including oxidation, reduction (Ce(IV) to Ce(III)), and reoxidation, forming Ce7O12 and CeF3, influencing flotation behavior via oxygen vacancies and surface area.

Conclusions:

• The MPT strategy effectively enhances the separation of rare-earth elements from low-grade ores.
• Understanding the surface chemistry changes during MPT is crucial for optimizing flotation performance.
• This approach offers a promising pathway for the comprehensive utilization of complex, low-grade rare-earth resources.