Process development to recover rare earth metals from monazite mineral: A review

• Review on leaching studies of rare earth metals from monazite.
• Beneficiation using flotation, gravity, electrostatic and magnetic devices.
• Comparative studies with various leachants.
• Useful review for process developers and related industrialists.

The escalating demand of rare earth metals (REMs) in various applications and their continuous depleting ores have laid emphasis to produce metals from their complex resources by developing energy efficient and eco-friendly processes. Present review reports the commercial processes based on pyro–hydro or hybrid techniques as well as systematic research for process development to recover rare earth from monazite. The salient findings on mining and physical beneficiation of different beach sand deposits containing monazite are reviewed. Monazite concentrate obtained are processed under different condition of time, temperature and concentration using acidic or alkaline solution. They are usually processed using thermal treatment followed by REMs recovery under optimized conditions of leaching and their extraction via solvent extraction, precipitation, etc. to produce salts/concentrate of REMs from the leached solution. The processes developed to recover REMs are reviewed and recommendations are made in respect to various methodologies and objectives.