Abstract: A method for extracting rare earth elements and critical minerals including adding an acid to a mixture comprising organically bound rare earth elements. The mixture is maintained at a pH of 0.25 to 4 for a period of time, resulting in a liquor and a leached mixture. The liquor is removed from the leached mixture to form a dewatered cake. The dewatered cake is washed to form a washing liquid. The washing liquid is recycled to create a second slurry comprising organically bound rare earth elements.

Abstract: Novel methods of recovering neodymium and related rare earth elements from permanent magnets of various compositions are described. The methods employ processing steps including converting the magnet material to a higher surface area form such as a powder, treating the mixture with alkaline solutions to form product concentrated in neodymium and rare earth metals. Inexpensive materials such as ammonia, ammonium carbonate, carbon dioxide, water are recycled in a process that uses moderate temperatures, pressures and non-corrosive and environmentally-friendly chemicals.

Abstract: A method of separating scandium from a feedstock wherein a scandium enriched solution is produced from the feedstock and the scandium enriched solution is extracted to produce an organic phase of the scandium enriched solution. The organic phase of the scandium enriched solution is re-extracted to produce an aqueous phase including scandium chloride. The aqueous phase is precipitated and calcinated to produce scandium oxide powder.

Abstract: The invention relates to a method of separating and extracting rare-earths from rare-earth polishing powder waste and regenerating rare-earth polishing powder, which is characterized by: firstly, process the waste powder with first acid leaching, alkali roasting, and second acid leaching to separate and extract rare-earths from rare-earth polishing powder waste to obtain the leaching solution of rare-earth chloride; secondly, precipitate from the leaching solution with ammonia to remove impurities and hydrochloric acid solution to obtain the purified solution of rare-earth chloride; thirdly, co-precipitate from the solution acquired in the second step with hydrofluoric acid, ammonium bicarbonate, and dispersant to obtain the lanthanum cerium fluoro-carbonate; and finally, after drying, two-stage high-temperature calcination, and ball milling, the regenerated rare-earth polishing powder with decent polishing performance can be obtained.

Abstract: Disclosed are methods of making porous zinc electrodes. Taken together, the steps are: forming a mixture of water, a soluble compound that increases the viscosity of the mixture, an insoluble porogen, and metallic zinc powder; placing the mixture in a mold to form a sponge; optionally drying the sponge; placing the sponge in a metal mesh positioned to allow air flow through substantially all the openings in the mesh; heating the sponge in an inert atmosphere at a peak temperature of 200 to 420° C. to fuse the zinc particles to each other to form a sintered sponge; and heating the sintered sponge in an oxygen-containing atmosphere at a peak temperature of 420 to 700° C. to form ZnO on the surfaces of the sintered sponge. The heating steps burn out the porogen.

Abstract: A method of producing ceria nanocrystals is provided. The method includes providing a gas that includes ozone to a solution that includes a cerium salt, and obtaining ceria nanocrystals from the solution after the gas is provided to the first solution. A method of producing nanoparticles is provided. The method includes providing a gas that includes ozone to a solution that includes a metal salt that includes at least one of a transition metal or a lanthanide, and producing at least one of metal oxide nanoparticles, metal oxynitrate nanoparticles, or metal oxyhydroxide nanoparticles from the solution after the gas is provided to the solution.

Abstract: The invention relates to a method for recovery of Nd2Fe14B grains from bulk sintered Nd—Fe—B magnets and/or magnet scraps. In this method the Nd—Fe—B magnets (1) and/or magnet scraps are anodically oxidized using a non-aqueous liquid electrolyte (5), said anodic oxidation releasing the Nd2Fe14B grains (6) in said Nd—Fe—B magnets (1) and/or magnet scraps. The released Nd2Fe14B grains (6) are collected during and/or after said anodic oxidation. The proposed method allows a more environmental friendly and cost-effective way for recycling EOL Nd—Fe—B magnets/Nd—Fe—B magnet scraps.

Abstract: Disclosed is a method and system for recovering at least rare earth elements from within an object A consisting of at least one first rare earth portion or a mixture of rare earth elements and a second metal portion. The method includes a solvothermal treatment step that places the object in contact with a fluid for causing at least one rare earth portion and/or mixture of rare earth elements and the metal portion to oxidize in order to separate same, the value of the reaction temperature Tr is selected according to the nature of the object, the reaction following a R-M?R(X)x+M(X)y scheme, where R is the rare earth element or a mixture of rare earth elements, M is the transition metal, and (X) is a group which depends on the fluid used.

Abstract: There are provided processes for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum, the process comprising: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum with lithium hydroxide, sodium hydroxide and/or potassium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate to an electromembrane process for converting the lithium sulfate, sodium sulfate and/or potassium sulfate into lithium hydroxide, sodium hydroxide and/or potassium hydroxide respectively; reusing the sodi

Abstract: The present invention discloses a process for recovery and regeneration of rare earth metals or salts thereof used as catalyst and which is conveniently integrated within the overall flow sheets of manufacturing dialkyl carbonates. Alkyl carbamate, alcohol and a rare earth metal salt as catalyst selected from the lanthanide series are added in a reactor to afford dialkyl carbonate. The rare earth metal catalyst is selected from samarium, cerium, lanthanum, neodymium, ytterbium, europium and gadolinium. Ammonia is added to a portion of the reaction mixture to precipitate the catalyst and the separated deactivated catalyst is dissolved in acid to afford regenerated catalyst, e.g., in triflic acid in the case of samarium triflate catalyst.

Abstract: Disclosed are methods of making porous zinc electrodes. Taken together, the steps are: forming a mixture of water, a soluble compound that increases the viscosity of the mixture, an insoluble porogen, and metallic zinc powder; placing the mixture in a mold to form a sponge; optionally drying the sponge; placing the sponge in a metal mesh positioned to allow air flow through substantially all the openings in the mesh; heating the sponge in an inert atmosphere at a peak temperature of 200 to 420° C. to fuse the zinc particles to each other to form a sintered sponge; and heating the sintered sponge in an oxygen-containing atmosphere at a peak temperature of 420 to 700° C. to form ZnO on the surfaces of the sintered sponge. The heating steps burn out the porogen.

Abstract: The present invention relates to cerium oxide particles that have excellent heat resistance especially useful for catalysts, functional ceramics, solid electrolyte for fuel cells, polishing, ultraviolet absorbers and the like, and particularly suitable for use as a catalyst or co-catalyst material, for instance in catalysis for purifying vehicle exhaust gas. The present invention also relates to a method for preparing such cerium oxide particles, and a catalyst, such as for purifying exhaust gas, utilizing these cerium oxide particles.

Abstract: The invention relates to a method for producing a scandium-containing concentrate from the wastes of alumina production and extracting high-purity scandium oxide from the same. Provided is a method for producing a scandium-containing concentrate from a red mud, wherein the Sc2O3 content therein is least of 15 wt. %, the TiO2 content not more than 3 wt. %, the ZrO2 content not more than 15 wt. %, and wherein scandium in the concentrate is in form of a mixture of Sc(OH)3 hydroxide with ScOHCO3.4H2O. Also provided is a method for producing high-purity scandium oxide, with a purity of approximately 99 wt. %.

Abstract: Provided is a method for obtaining high-purity scandium oxide efficiently from a solution containing scandium. The method for producing high-purity scandium oxide of the present invention has a first firing step S12 for subjecting a solution containing scandium to oxalation treatment using oxalic acid and firing the obtained crystals of scandium oxalate at a temperature of 400 to 600° C., inclusive, a dissolution step S13 for dissolving the scandium compound obtained by firing in one or more solutions selected from hydrochloric acid and nitric acid to obtain a solution, a reprecipitation step S14 for subjecting the solution to oxalation treatment using oxalic acid and generating a reprecipitate of scandium oxalate, and a second firing step S15 for firing the reprecipitate of obtained scandium oxalate to obtain scandium oxide.

Abstract: An environment control system utilizes oxygen and humidity control devices that are coupled with an enclosure to independently control the oxygen concentration and the humidity level within the enclosure. An oxygen depletion device may be an oxygen depletion electrolyzer cell that reacts with oxygen within the cell and produces water through electrochemical reactions. A desiccating device may be g, a dehumidification electrolyzer cell, a desiccator, a membrane desiccator or a condenser. A controller may control the amount of voltage and/or current provided to the oxygen depletion electrolyzer cell and therefore the rate of oxygen reduction and may control the amount of voltage and/or current provided to the dehumidification electrolyzer cell and therefore the rate of humidity reduction. The oxygen level may be determined by the measurement of voltage and a limiting current of the oxygen depletion electrolyzer cell. The enclosure may be a food or artifact enclosure.

Abstract: A method for separating a light rare earth element and a heavy rare earth element includes at least the steps of: (1) obtaining, from a workpiece containing a light rare earth element and a heavy rare earth element, a composite oxide or mixture of oxides of the two; (2) dissolving the obtained composite oxide or mixture of oxides in hydrochloric acid and/or nitric acid; (3) adding a precipitant to the obtained solution to give a precipitate; (4) calcining the obtained precipitate; (5) adding the obtained calcine in an amount of 1.1 times to 3.0 times the upper solubility limit to hydrochloric acid and/or nitric acid having a concentration of 0.7 mol/L or more to give a solution and a residue; and (6) separating the obtained solution and residue, thereby giving the solution as a light rare earth element-rich inclusion and the residue as a heavy rare earth element-rich inclusion.

Abstract: A process for separating rare earth elements (REE) from Ca, Mg and other non-REE elements comprises raising the pH of an acidic aqueous solution of REE to pH 8 to pH 11; adding nano- or micro (NoM) particles having a silica or titanium oxide surface; agitating the suspension for 6 h to 48 h to provide for adherent crystallization of REE hydroxide on the particles; separating the particles from the solution; releasing REE by treatment with aqueous acid to form an aqueous solution of REE salt; separating them from the aqueous solution of REE salt formed. The acidic aqueous solution comprising REE is preferably provided by leaching of an REE mineral with aqueous acid; adding a base to bring the pH to from pH 4.0 to pH 6.5; separating precipitated non-REE hydroxide from the solution.

Abstract: The present invention relates to a method of separating rare earth elements from rare earth polishing powder waste by a hydrometallurgical process, the method comprising the steps of: synthesizing sodium rare-earth double sulfates by adding sulfuric acid and sodium hydroxide to the rare earth polishing powder waste; converting the sodium rare-earth double sulfates into rare earth hydroxides; and separating cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd) from the rare earth hydroxides by adding hydrochloric acid and sulfuric acid. The present invention makes it possible to recover 99% or more of rare earth elements, including cerium (Ce), lanthanum (La), praseodymium (Pr), and neodymium (Nd) from rare earth polishing powder waste, and enables the recovered rare earth elements to be recycled, thereby achieving great industrial economic benefits.

Abstract: A cerium-based abrasive that achieves a high polishing rate and suppresses the occurrence of surface defects such as scratches and pits and the deposition of the abrasive particles on the polished surface in surface polishing of glass substrates or the like, at low cost with a high production efficiency. The cerium-based abrasive includes a cubic composite rare earth oxide and a composite rare earth oxyfluoride, containing 95.0 to 99.5 mass % of total rare earth elements in terms of oxides, containing 54.5 to 95.0 mass % of cerium in terms of oxide, 4.5 to 45.0 mass % of lanthanum in terms of oxide, and 0.5 to 2.0 mass % of neodymium in terms of oxide relative to the total rare earth elements in terms of oxides, containing 0.5 to 4.0 mass % of fluorine atoms, and containing 0.001 to 0.50 mass % of sodium atoms relative to the total rare earth elements in terms of oxides.

Abstract: A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

Abstract: A chemical dissolution method is provided for use in recycling rare earth metal-containing material such as permanent magnet material including end-of-life magnet shapes, magnet scrap and Terfenol-D alloy material by mixing the rare earth metal-containing material and an aqueous solution of a copper (II) salt to dissolve the material in the solution. The dissolved rare earth metal is then precipitated from the aqueous solution as a rare earth metal compound, such as a rare earth metal oxalate, sulfate or phosphate from which rare earth metal oxide can be obtained.

Abstract: The application relates to a process for rare earth extraction and thorium removal from monazite or bastnasite bearing ores or ore beneficiation and industrial waste containing a variable amount of rare earth elements as oxides, phosphates, carbonates or sulfates, comprising (i) controlled mixture between sulfuric acid and the material containing rare earth and (ii) water leaching under controlled conditions.

Abstract: Wood markers and processes for durably marking and subsequently identifying both original grain wood products and wood-plastic composite products. The wood marker can be dispersed beneath the surface of the wood, where it is protected from the elements and may endure years of exposure to the elements. The wood marker is compatible with state-of-the-art pressure-treating processes and may subsequently be detected for authentication purposes by known analytical methods.

Abstract: Disclosed is a method of recovering rare earth, aluminum and silicon from rare earth-containing aluminum-silicon scrap. The method comprises: S1, acid-leaching the rare earth-containing aluminum-silicon scrap with an inorganic acid aqueous solution to obtain a silicon-rich slag and acid leached solution containing rare earth and aluminum element; S2, adding an alkaline substance into the acid leached solution containing the rare earth and aluminum element and controlling a PH value of the acid leaching solution between 3.5 to 5.2, performing a solid-liquid separation to obtain a aluminum hydroxide-containing precipitate and a rare earth-containing solution filter; S3, reacting the aluminum hydroxide containing precipitate with sodium hydroxide to obtain sodium metaaluminate solution and aluminum-silicon slag, and preparing a rare earth compound product with the rare earth-containing filtrate.

Abstract: Provided is a method for recovering scandium with which scandium can be efficiently recovered as high purity scandium oxide from a scandium-containing solution containing impurities such as iron without causing problems such as increased cost and safety problems. According to the method for recovering scandium according to the present invention, the pH of a solution containing scandium and iron (scandium-containing solution) is adjusted within the range of not less than ?0.5 and less than 1, then scandium oxalate is obtained by adding the pH adjusted solution to an oxalic acid solution, and the scandium oxalate is roasted into scandium oxide.

Abstract: The present invention relates to an improved process for the purification of polyaminocarboxylates such as DOTA, DTPA, DO3A-butrol, BOPTA.

Abstract: Provided are: an extractant which is capable of quickly and highly efficiently extracting zirconium from an acidic solution that is obtained by acid leaching a material containing zirconium and scandium such as an SOFC electrode material; and a method for extracting zirconium, which uses this extractant. A zirconium extractant according to the present invention is composed of an amide derivative represented by general formula (I). In the formula, R1 and R2 respectively represent the same or different alkyl groups, each of which may be linear or branched; R3 represents a hydrogen atom or an alkyl group; and R4 represents a hydrogen atom or an arbitrary group other than an amino group, said arbitrary group being bonded, as an amino acid, to the ? carbon.

Abstract: A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.

Abstract: In order to recover high-quality scandium from nickel oxide ores efficiently, this method comprises: a step (S1) for feeding Ni oxide ores and sulfuric acid into a pressure vessel, and subjecting the mixture to solid-liquid separation to form a leachate and a leach residue; a step (S2) for adding a neutralizing agent to the leachate, and thus forming a neutralization sediment and a post-neutralization fluid; a step (S3) for adding a sulfurizing agent to the post-neutralization fluid, and separating the obtained mixture into Ni sulfide and a post-sulfurization fluid; a step (S4) for bringing the post-sulfurization fluid into contact with a chelating resin, making Sc adsorbed on the chelating resin, and forming an Sc eluent; a step (S6) for bringing the Sc eluent into contact with an extracting agent, adding a back-extraction agent to the extract, and forming back-extracted matter; and a step (S8) for roasting the back-extracted matter, and forming Sc oxide.

Abstract: A method for making lithium iron phosphate is provided. A lithium chemical compound, a ferrous chemical compound, and a phosphate-radical chemical compound are mixed in an organic solvent to form a mixture. The mixture is solvothermal reacted in a solvothermal reactor at a predetermined temperature. A protective gas is introduced into the solvothermal reactor during the solvothermal reaction to increase a pressure in the solvothermal reactor to a level higher than a self-generated pressure of the solvothermal reaction.

Abstract: A method for comprehensively recovering rare earth elements and fluorine element in a bastnaesite treatment process. The method comprises: oxidation roasting a bastnaesite, and leaching a roasted mixture using a hydrochloric acid, adding a roasting promoter to the bastnaesite during the roasting process; and/or during the leaching process using the hydrochloric acid, adding a catalytic leaching promoter into the mixture, obtaining a rare earth chloride solution containing little cerium element and a cerium-rich residue containing the fluorine element; and separating and recovering rare earth fluorides from the cerium-rich residue.

Abstract: It is described a method for recovering rare earth elements from low grade ores including a first metal selected group containing at least one of iron and aluminum and a second metal selected from the group consisting of at least of the rare earth elements (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium), the method comprising the steps of: (i) contacting the ore with sulfuric acid to obtain sulfates of the first group of metals, (ii) subjecting the mixture to high temperatures in order to convert the first group of sulfates into phosphates or other stable species and the second group into sulfates, (iii) adding water to the cool mixture, selectively dissolving the rare earth elements and (iv) subjecting the rare earth solution to a purification process.

Abstract: In order to selectively extract copper and/or lead from an acidic solution containing high concentrations of manganese, etc., the valuable-metal extracting agent of the present invention is expressed by general formula (1). In the formula, R1 and R2 each represent the same or different alkyl groups, R3 represents a hydrogen atom or an alkyl group, and R4 represents a hydrogen atom or a given group, other than an amino group, that bonds with an ? carbon as an amino acid. In general formula (1), the inclusion of a glycine unit, a histidine unit, a lysine unit, an asparagine acid unit, or a normal methylglycine unit is preferred. When using the extracting agent to extract copper/and lead, it is preferable that the pH of the acidic solution be adjusted to 1.0-5.5 inclusive.

Abstract: A process for making nanoparticles of biocompatible materials is described, wherein an aqueous reaction mixture comprising cerous ion, citric acid, an oxidant, and water, is adjusted to a predetermined range of pH, held at temperature conditions to directly form, without isolation, a stable dispersion of cerium oxide nanoparticles. Dispersions of these biocompatible cerium oxide nanoparticles exhibit self-life well in excess of one year, and may be used to prevent and/or treat disease or injury, such as oxidative stress related diseases and events.

Abstract: An objective of the invention is to provide a method and system for separating a particular rare earth element from a rare earth magnet at a high separation ratio and by a simple process. There is provided a rare earth separation method for separating a first and a second groups of rare earth elements contained in a magnet, the method including: a starting powder preparation step from the magnet; a magnet component oxidation heat treatment step; a rare earth oxide separation step from the magnet components oxide powder; a powder size optimization step; a chlorinating agent mixing step; a chlorination/oxychlorination heat treatment step of forming a “first group rare earth chlorides”/“second group rare earth oxychlorides” mixture; a selective dissolution step of selectively dissolving the first group rare earth chlorides in the solvent and leaving the second group rare earth oxychlorides undissolved in solid phase form; and a solid-liquid separation step.

Abstract: The present invention relates to a leaching method of rare-earth metals using a hydrochloric acid from a manganese nodule, and more particularly, to a leaching method of rare-earth metals using a hydrochloric acid from a manganese nodule, in which a manganese nodule is mixed with a hydrochloric acid, then stirred and heated to leach the rare-earth metal included in the manganese nodule.

Abstract: In an extraction tank, a plating solution containing rare earth metal ions is treated with an extracting solution of an extractant in a water-insoluble organic solvent. Extraction treatment is carried out by atomizing the extracting solution through a lower nozzle into the plating solution in the tank lower zone, and atomizing the plating solution through an upper nozzle into the extracting solution in the tank upper zone, for thereby bringing the plating solution in contact with the extracting solution to extract rare earth metal ions from the plating solution into the extractant for removal.

Abstract: The object of the present invention is to provide a method for recovering a rare earth element, which is capable of efficiently recovering a rare earth element with high recovery rate without using any expensive chemicals, solvents or the like. In the present invention, a water-soluble salt other than sulfate ions is allowed to coexist with an aqueous solution that contains a rare earth element, and then an alkali metal sulfate is added to the aqueous solution, thereby producing a precipitate of a double sulfate of the rare earth element.

Abstract: The invention belongs to the field of recycling of resources, in particular to a method for waste rare earth luminescent material by dual hydrochloric acid. First hydrochloric acid was used to dissolve the red phosphor powder (Y2O3:Eu) priority, and yttrium-rich rare earth chloride solution and residue were obtained after filtered. Residue's major components were green and blue phosphor powder, and the removal of Ca2+ in filtrate was conducted by using Na2SO4, and CaSO4 precipitation separation was conducted to get rich rare earth chloride solution, europium and yttrium. Residue was mixed with alkali to perform alkaline fusion at high temperature to decompose green and blue powder, then sodium aluminate, magnesium, barium and rare earth oxides were obtained. Alkaline fusion products were washed with water, and filtered, and then sodium aluminate solution and residues containing rare earth oxides were obtained.

Abstract: Provided is a method for preparing a vanadia-titania catalyst, comprising: vaporizing a titanium precursor; conveying the vaporized titanium precursor to a reaction unit together with an oxygen supplying source; reacting the vaporized titanium precursor conveyed to the reaction unit with the oxygen supplying source to produce titania particles; condensing the titania particles, collecting and recovering them; mixing the recovered titania particles with a vanadium precursor solution; drying the mixture of the titania particles with the vanadium precursor solution; and calcining the dried mixture under oxygen atmosphere or air. Provided also is a vanadia-titania catalyst obtained by the method. The vanadia-titania catalyst has a large specific surface area, uniform and fine nano-scaled size, and high dispersibility, thereby providing excellent nitrogen oxide removal efficiency, particularly in a low temperature range of 200° C.-250° C.

Abstract: The present invention relates to a process for selectively removing molybdenum from a solution which contains molybdenum, said process comprising the following steps: bringing the solution to an acid pH lower than or equal to 3, preferably lower than or equal to 2, even more preferably lower than or equal to 0.

Abstract: There are provided processes for recovering at least one rare earth element. Such processes comprise obtaining an acidic composition comprising (i) at least one rare earth element and optionally at least one rare metal; and reacting the composition with a precipitating agent so as to substantially selectively precipitate a first rare earth element and optionally a first rare metal. For example, various rare earth elements (such as scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, etc) and various rare metals (such as indium, zirconium, lithium, gallium, etc.) can be extracted by using such processes.

Abstract: The present invention relates to a method for synthesizing water-soluble particles, the method includes providing a solution including a lanthanide compound, a halide compound, and a first solvent; introducing a capping agent into the solution to form a mixture; heating the mixture under pressure to produce the particles; and recovering the particles from the mixture. The present invention also relates to a water-soluble particle having a surface functional group. The particles exhibit up-conversion luminescence utilizing NIR excitation, wherein the particles are synthesized in a one-pot process.

Abstract: 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.

Abstract: A method for recovering rare earth compounds, vanadium and nickel from waste vanadium-nickel catalysts, comprising steps of: acid leaching, by soaking waste vanadium-nickel catalysts into a sulfuric acid solution and obtaining a mixture containing alumina silica slag; sedimentation, by filtering out the alumina silica slag from the mixture to obtain a filtrate, and then adding a salt into the filtrate to precipitate rare earth double salts followed by isolating a sediment of rare earth double salts and a liquid solution via filtration; and extraction, by providing and adding an alkali into the sediment of rare earth double salts followed by further soaking the rare earth double salts in an acid solution to precipitate rare earth oxalate or rare earth carbonate, and adding an oxidizer into the liquid solution to adjust the pH value thereof and then extracting vanadium and nickel from the liquid solution via an ion-exchange resin.

Abstract: A method of making cerium-containing metal oxide nanoparticles in non-polar solvent eliminates the need for solvent shifting steps. The direct synthesis method involves: (a) forming a reaction mixture of a source of cerous ion and a carboxylic acid, and optionally, a hydrocarbon solvent; and optionally further comprises a non-cerous metal ion; (b) heating the reaction mixture to oxidize cerous ion to ceric ion; and (c) recovering a nanoparticle of either cerium oxide or a mixed metal oxide comprising cerium. The cerium-containing oxide nanoparticles thus obtained have cubic fluorite crystal structure and a geometric diameter in the range of about 1 nanometer to about 20 nanometers. Dispersions of cerium-containing oxide nanoparticles prepared by this method can be used as a component of a fuel or lubricant additive.

Abstract: The disclosure relates generally to recovering bond coat materials and barrier coat materials from co-mingled mixtures of bond coat and barrier coat materials (e.g., plasma overspray waste), and from mixtures of co-mingled bond coat and barrier coat materials stripped from a substrate. The disclosure also relates to recovering rare earth elements (e.g., yttrium) from a barrier coat of the co-mingled plasma overspray waste or mixture of co-mingled bond coat and barrier coat materials stripped from the substrate.

Abstract: The objective of the present invention is to selectively extract light rare earth metals, and by extension, europium, from an acidic solution containing a plurality of types of rare earth metal. This valuable metal extraction agent is represented by the general formula. In the formula: R1 and R2 each indicate the same or different alkyl group; R3 indicates a hydrogen atom or an alkyl group; and R4 indicates a hydrogen atom or any given group other than an amino group bonded to the ? carbon as an amino acid. Preferably, the general formula has a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit, or an N-methylglycine unit. Preferably, when extracting europium using the extraction agent, the pH is adjusted into the range of 2.0-3.0 inclusive, and when selectively extracting light rare earth metals, the pH is adjusted to 1.7-2.7 inclusive.

Abstract: A method is presented for recovery, in reusable form, of rare earth minerals and zirconia from waste materials containing them. The method includes: mixing an ammonium sulfate powder and a powder containing the oxide waste material; heating the mixture to decompose the waste into a residue; dissolving the residue in water; separating rare earth constituents from the solution; and subsequently using the separated rare earth constituent (salt or solution) as a raw material. Moreover, the reactants used in the recovery may be recovered by appropriate precipitation and concentration operations.

Abstract: A mineral processing facility is provided that includes a cogen plant to provide electrical energy and waste heat to the facility and an electrochemical acid generation plant to generate, from a salt, a mineral acid for use in recovering valuable metals.