699results about "Rare earth metal compounds preparation/treatment" patented technology

The production method for cerium oxide particles of the present invention is a method of producing a cerium oxide particle by heating a cerium compound from a normal temperature to a temperature range of 400° C. to 1200° C., and comprises at least a temperature raising stage of a temperature rise speed of 2° C./hour to 60° C./hour, or proceeds via a stage of heating while supplying a humidified gas in a temperature raising process. By the method of the present invention, a cerium oxide powder whose particle diameter distribution of primary particles is narrow can be obtained. An aqueous cerium oxide slurry produced from the powder enables an improvement in the productivity and a reduction in the cost of a polishing step, because if it is used as an abrasive a high-quality polished face is obtained without deteriorating the polishing speed. The aqueous cerium oxide slurry of the present invention is particularly useful as an abrasive for final finish of a substrate whose main component is silica.

Processes described include reacting a fresh or spent catalyst, or sorbent, with a solution containing an extracting agent (such as an acid or a base). Preferably, the catalyst contains both alumina and a molecular sieve (or a sorbent), and the reaction is performed under relatively mild conditions such that the majority of the base material does not dissolve into the solution. Thus, the catalyst can be re-used, and in certain instances the performance of the catalyst even improves, with or without re-incorporating certain of the metals back into the catalyst. Additionally, metals contained in the catalyst, such as Na, Mg, Al, P, S, Cl, K, Ca, V, Fe, Ni, Cu, Zn, Sr, Zn Sb, Ba, La, Ce, Pr, Nd, Pb, or their equivalent oxides, can be removed from the catalyst. Some of the metals that are removed are relatively valuable (such as the rare earth elements of La, Ce, Pr and Nd).

The invention concerns a cyclic method for separating at least one chemical element E1 from at least one chemical element E2 from an aqueous solution containing said elements, which employs a mixture of two extractants operating in non-overlapping chemical fields. Each cycle of said method comprises: a) co-extracting elements E1 and E2 by means of an organic phase containing a first extractant suited to causing the migration of said elements into said organic phase; b) adding to the organic phase a second extractant suited to selectively retaining the element(s) E2 in said organic phase during step c): c) selectively stripping the element(s) E1 from the organic phase; d) selectively stripping the element(s) E2 from the organic phase; e) separating the first and second extractants present in said organic phase at the end of step d).

Provided is a method of recovering rare-earth elements by which rare-earth elements can be recovered efficiently from a bauxite residue serving as a raw material and containing the rare-earth elements. Specifically provided is a method of recovering rare-earth elements from a raw material, the raw material being a bauxite residue produced as a by-product in a Bayer process, the method including: using a bauxite residue having a specific surface area of 35 m²/g or more; adding, to the raw material bauxite residue, a liquid leaching agent formed of an aqueous solution of at least one kind of mineral acid selected from sulfuric acid, hydrochloric acid, nitric acid, and sulfurous acid, thereby preparing a slurry having a liquid-solid ratio of 2 to 30 and a pH of 0.5 to 2.2; subjecting the slurry to leaching treatment of the rare-earth elements under a temperature condition of room temperature to 160° C.; subjecting the slurry after the leaching treatment to solid-liquid separation, yielding a leachate; and separating and recovering the rare-earth elements from the leachate.

Provided are a method of preparing solid electrolyte particles of Chemical Formula 1 including preparing a precursor solution by mixing a titanium precursor, a lanthanum precursor, and a lithium precursor in an aqueous or organic solvent, and heat treating the precursor solution, solid electrolyte particles prepared thereby, and a lithium secondary battery including the solid electrolyte particles:

Li_3xLa_(2/3-x)TiO₃ (0<x<0.16).   <Chemical Formula 1>

According to a method of preparing solid electrolyte particles according to an embodiment of the present invention, solid electrolyte particles may be easily prepared by heat treating at low temperature for a short period of time.

The invention discloses a preparation method of anhydrous lanthanum bromide, which comprises the following steps: (1) well mixing ammonium bromide with lanthana; (2) heating the mixture obtained in step (1) in closed environment with a certain leakproofness to obtain anhydrous lanthanum bromide. The method of the invention is easily available in raw materials, and low in cost; the preparation process is simple, short in flow, easy to control, high in product yield, and low in production cost; the prepared anhydrous lanthanum bromide is high in purity, and has a purity of up to 99.5%; and the preparation method can be used for preparation of lanthanum bromide scintillation crystals, and has very good industrial and commercial prospects.

The present invention relates to a method for preparing cerium carbonate-based compound, which is capable of easily controlling the crystalline structure, size, shape, or etc. of the cerium carbonate-based compound, and of preparing the cerium carbonate-based compound efficiently at low cost.

The method for preparing cerium carbonate-based compound includes comprising the steps of reacting Lanthanite-(Ce) at an elevated temperature to form cerium oxycabonate hydrate (Ce₂O(CO₃)₂.H₂O) with orthorhombic crystal structure, or cerium hydroxycarbonate (Ce(OH).(CO₃)) with hexagonal crystal structure.

The invention relates to a method for separating and extracting rare earth and regenerated rare earth polishing powder from waste rare earth polishing powder. The method is characterized by comprising the following steps that a primary acid leaching, alkali fusion and secondary acid leaching combined treatment process is firstly used for separating and extracting the rare earth in the waste rare earth polishing powder to obtain rare earth chloride leachate; then ammonia water is used for precipitation and impurity removing, and hydrochloric acid is used for acidolysis to obtain a purified rare earth chloride solution; then, hydrofluoric acid, an ammonium bicarbonate solution and a dispersing agent are used for coprecipitation to obtain a rare earth chloride solution so as to obtain cerium lanthanum fluorocarbonate powder; and finally, the regenerated rare earth polishing powder with good polishing performance is obtained through drying, two-stage high-temperature calcination and ball milling. According to the method, the total leaching rate of the rare earth in the waste rare earth polishing powder reaches 95% or above, the total recycle rate of the rare earth reaches 93% or above, and efficient separation, extraction and recycling of the rare earth in the waste rare earth polishing powder are achieved.

The present invention relates to methods for the separation of rare earth elements from aqueous solutions and, more particularly, to the separation of lanthanides (e.g., neodymium(III)) from aqueous solutions using an organo phosphorus functionalized adsorbent.

The invention provides a nano-dephosphorizer lanthanum carbonate hydrate, La2(CO3)3.nH2O, 1 <= n <= 8. The invention also provides a preparation method of the nano-dephosphorizer lanthanum carbonate hydrate. The method includes steps of: 1) adding an ionic liquid to a metal lanthanum ion solution with stirring to form a mixed solution; 2) adding a precipitant to the mixed solution to perform a precipitation reaction, and performing after-treatment to a reaction product to obtain the nano-dephosphorizer lanthanum carbonate hydrate, which is more than 100 mg/L in maximum saturation adsorption capacity and has strong removal capability on low-content phosphorus components in ecologic water domains, living or industrial wastewater, etc. After treatment, content of phosphates in the water sample can reach national first-level emission standard of phosphates. The nano-dephosphorizer has important significance for alleviating the gaining pressure of phosphorus environment pollution and a problem of daily production and domestic water.

A method is described to produce high purity rare earth oxides of the elements La, Ce, Tb, Eu and Y from phosphor, such as waste phosphor powders originating in various consumer products. One approach involves leaching the powder in two stages and converting to two groups of relatively high purity mixed rare earth oxides. The first group containing Eu and Y is initially separated by solvent extraction. Once separated, Eu is purified using Zn reduction with custom apparatus. Y is purified by running another solvent extraction process using tricaprylmethylammonium chloride. Ce is separated from the second group of oxides, containing La, Ce and Tb by using solvent extraction. Subsequently, La and Tb are separated from each other and converted to pure oxides by using solvent extraction processes. A one-stage leaching process, wherein all rare earths get leached into the solution and subsequently processed, is also described.