Dy.sub.2O.sub.3 particles of a nanoparticle scale have beneficial properties for ceramic and electronic uses. Disclosed herein are moderately dispersed Dy.sub.2O.sub.3 particles having regular morphology and lateral size ranging from about 10 nm to 1 m. The Dy.sub.2O.sub.3 particles may exhibit a narrow particle size distribution such that the difference between D.sub.10 and D.sub.90 is about 0.1 m to 1 m. Further disclosed are processes of producing these moderately dispersed Dy.sub.2O.sub.3 particles. These processes do not include grinding to obtain the particles. Also disclosed herein are uses for these Dy.sub.2O.sub.3 particles.

The present disclosure discloses a method for preparing rare earth oxide by recycling ammonia and carbon, comprising the steps of: (1) heating raw materials containing a first rare earth carbonate and a first rare earth oxide with microwave and calcining at 500-1000 C. for 20-120 min to obtain a second rare earth oxide and carbon dioxide; (2) reacting carbon dioxide with a first ammonia water to obtain a precipitant; (3) reacting the precipitant with rare earth chloride to obtain a second rare earth carbonate and ammonium chloride wastewater. In the method, calcination time is short, rare earth recovery rate, utilization rate of ammonia and carbon resources are high. The present disclosure also provides a use of a rare earth oxide in shortening calcination time and/or increasing rare earth yield.

The present disclosure discloses a method for preparing rare earth oxide by recycling ammonia and carbon, comprising the steps of: (1) heating raw materials containing a first rare earth carbonate and a first rare earth oxide with microwave and calcining at 500-1000 C. for 20-120 min to obtain a second rare earth oxide and carbon dioxide; (2) reacting carbon dioxide with a first ammonia water to obtain a precipitant; (3) reacting the precipitant with rare earth chloride to obtain a second rare earth carbonate and ammonium chloride wastewater. In the method, calcination time is short, rare earth recovery rate, utilization rate of ammonia and carbon resources are high. The present disclosure also provides a use of a rare earth oxide in shortening calcination time and/or increasing rare earth yield.