Embodiments relate to methods for generating selected materials from a natural brine, where the natural brine is sea water, saline water, fresh water, synthetic solutions, or industrial liquid wastes. A natural brine comprising at least a portion of a selected material is heated. CO.sub.2 is added and mixes with the natural brine forming a mixture such that the CO.sub.2/P is a first predetermined value. The mixture is held so that impurities in the natural brine precipitate as solids leaving a second brine substantially comprising the selected material. The second brine is heated. CO.sub.2 gas is injected into the second brine, mixing so that the CO.sub.2/P is a second predetermined value. The mixture is held so that the selected material precipitates out and are removed.

Embodiments relate to methods for generating selected materials from a natural brine, where the natural brine is sea water, saline water, fresh water, synthetic solutions, or industrial liquid wastes. A natural brine comprising at least a portion of a selected material is heated. CO.sub.2 is added and mixes with the natural brine forming a mixture such that the CO.sub.2/P is a first predetermined value. The mixture is held so that impurities in the natural brine precipitate as solids leaving a second brine substantially comprising the selected material. The second brine is heated. CO.sub.2 gas is injected into the second brine, mixing so that the CO.sub.2/P is a second predetermined value. The mixture is held so that the selected material precipitates out and are removed.

A method for preparing lanthanum carbonate tetrahydrate and a product thereof. The lanthanum carbonate tetrahydrate is prepared by reacting lanthanum oxide and acetic acid with potassium carbonate or potassium bicarbonate or ammonium bicarbonate to prepare lanthanum carbonate octahydrate, and drying the lanthanum carbonate octahydrate. Compared with the lanthanum carbonate tetrahydrate in the prior art, the prepared lanthanum carbonate tetrahydrate has a characteristic spectral peak on a terahertz spectrum, and has excellent dissociation and dissolution characteristics of lanthanum ions.

A method for preparing lanthanum carbonate tetrahydrate and a product thereof. The lanthanum carbonate tetrahydrate is prepared by reacting lanthanum oxide and acetic acid with potassium carbonate or potassium bicarbonate or ammonium bicarbonate to prepare lanthanum carbonate octahydrate, and drying the lanthanum carbonate octahydrate. Compared with the lanthanum carbonate tetrahydrate in the prior art, the prepared lanthanum carbonate tetrahydrate has a characteristic spectral peak on a terahertz spectrum, and has excellent dissociation and dissolution characteristics of lanthanum ions.

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.

This invention provides a method for efficiently separating magnesium and lithium from salt lake brine, and simultaneously preparing high-purity magnesium oxide and battery-grade lithium carbonate. The detailed processing steps are as follows: (1) adding urea into the brine to dissolve, (2) placing the solution into the reactor for hydrothermal reaction, the magnesium ion will precipitate and enter the solid phase; (3) filtering and drying the production to get the magnesium carbonate solid, while the lithium ion remains in the liquid phase; (4) after directly concentration and precipitation, the battery-grade lithium carbonate can be obtained, while the calcination of solid-phase product results in the high-purity magnesium oxide. In this method, urea is used as the precipitant to separate magnesium and lithium in salt lake without introducing any new metal ion, and the brine solution is not diluted. The solid product is white and fluffy powder, which is easy to filter and separate. The extraction rate of lithium is high than 94%, and the purity of MgO obtained by calcination is higher than 99.5%.

This invention provides a method for efficiently separating magnesium and lithium from salt lake brine, and simultaneously preparing high-purity magnesium oxide and battery-grade lithium carbonate. The detailed processing steps are as follows: (1) adding urea into the brine to dissolve, (2) placing the solution into the reactor for hydrothermal reaction, the magnesium ion will precipitate and enter the solid phase; (3) filtering and drying the production to get the magnesium carbonate solid, while the lithium ion remains in the liquid phase; (4) after directly concentration and precipitation, the battery-grade lithium carbonate can be obtained, while the calcination of solid-phase product results in the high-purity magnesium oxide. In this method, urea is used as the precipitant to separate magnesium and lithium in salt lake without introducing any new metal ion, and the brine solution is not diluted. The solid product is white and fluffy powder, which is easy to filter and separate. The extraction rate of lithium is high than 94%, and the purity of MgO obtained by calcination is higher than 99.5%.

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.