The disclosure relates to cerium based particles having a rough surface and their use as a component of a polishing composition, especially for chemical mechanical polishing. The cerium based particles have substantially the shape of polyhedrons which have one or more faces with protrusions thereon, said protrusions being integrally formed with said cerium based particles. The present disclosure also relates to the method of preparation of the cerium based particles.

Disclosed are methods to produce Thermal Barrier Coating (TBC) products using materials recycled from TBC waste. These methods include ways to produce zirconium and rare earth chemicals and raw materials appropriate for producing TBC materials.

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 μm. 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 μm to 1 μm. 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.3μ particles.

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 μm. 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 μm to 1 μm. 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.3μ particles.

The invention relates to a system and a method for the processing of minerals containing the lanthanide series and the production of rare earth oxides, which allow a completely closed and continuous treatment of the different materials and desorbent agents involved in the process, thus improving the efficiency in the extraction and avoiding environmental risks associated. The method comprising the steps of: reception and conditioning of the raw material; desorption of valuable product through a plurality of mixing and reaction stages in which the raw material is contacted in countercurrent with a stream of desorbent solution; separation of fine solids; precipitation of secondary minerals through the use of a first reactive solution; precipitation of rare earth carbonates through the use of a second reactive solution; and drying and roasting of the rare earth carbonates to obtain rare earth oxides; wherein the method further comprises a secondary process that allows further processing of the residual mineral, and a dewatering and washing step wherein the residual mineral from the desorption step is washed and a lanthanide-containing liquid is recovered.

The invention relates to a system and a method for the processing of minerals containing the lanthanide series and the production of rare earth oxides, which allow a completely closed and continuous treatment of the different materials and desorbent agents involved in the process, thus improving the efficiency in the extraction and avoiding environmental risks associated. The method comprising the steps of: reception and conditioning of the raw material; desorption of valuable product through a plurality of mixing and reaction stages in which the raw material is contacted in countercurrent with a stream of desorbent solution; separation of fine solids; precipitation of secondary minerals through the use of a first reactive solution; precipitation of rare earth carbonates through the use of a second reactive solution; and drying and roasting of the rare earth carbonates to obtain rare earth oxides; wherein the method further comprises a secondary process that allows further processing of the residual mineral, and a dewatering and washing step wherein the residual mineral from the desorption step is washed and a lanthanide-containing liquid is recovered.

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.

The present invention relates to the recovery of metals from raw ores or concentrates, and more specifically, to the recovery of rare earth elements, or oxides or salts thereof, from ores containing bastnaesite carbonatite, and/or monazite. The ore is processed by a method that may include one or more of the following steps: (i) mechanically processing the ore; (ii) calcination and/or roasting of the ore to form a calcinated material and/or roasting of the ore to form a roasted material; (iii) leaching of the calcinated material or roasted material in an aqueous solution; (iv) solid/liquid separation to remove a solid residue from the aqueous solution to recover a rare earth element solution; and (v) precipitation of the rare earth element solution to isolate a rare earth element, or oxide or salt thereof.

The present invention is polishing particles for polishing a synthetic quartz glass substrate. The polishing particles contain cerium-based polishing particles and have a breaking strength, which is measured by a compression tester, of 30 MPa or more. This provides polishing particles for polishing a synthetic quartz glass substrate while sufficiently reducing generation of defects due to polishing.