Digestion of impure alumina with sulfuric acid dissolves all constituents except silica. Resulting sulfates, produced from contaminants in the impure alumina, remain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over metallic iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The remaining iron rich liquor also contains magnesium sulfate. Addition of oxalic acid generates insoluble ferrous oxalate which is thermally decomposed to ferrous oxide. Carbon monoxide reduces the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

The present disclosure relates to a method for producing lanthanide doped layered double hydroxides (Ln-doped LDHs). The method includes the steps of preparing a carbonate free alkaline solution; preparing a solution of metal salts comprising a salt of a lanthanide; co-precipitating the alkaline solution and the solution of metal salts to form a mixture and Ln-doped LDH precipitate wherein the pH of the mixture is maintained at a constant value; aging the precipitate; and separating the precipitate from the solution. The alkaline solution is an aqueous ammonia solution. The present disclosure is also related to lanthanide-doped layered double hydroxides (La-doped LDHs) obtainable by such a method, as well as to the use of the lanthanide-doped layered double hydroxides obtainable by such a method.

The present invention relates to the field of solid materials for the adsorption of lithium. In particular, the present invention relates to a novel process for preparing a solid crystalline material formed preferably in extrudate form, of formula (LiCl).sub.x.2Al(OH).sub.3,nH.sub.2O with n being between 0.01 and 10, x being between 0.4 and 1, comprising a step a) to precipitate boehmite under specific conditions of temperature and pH, a step to place the precipitate obtained in contact with a specific quantity of LiCl, at least one forming step preferably via extrusion, said process also comprising a final hydrothermal treatment step, all allowing an increase in lithium adsorption capacity and in the adsorption kinetics of the materials obtained compared to prior art materials, when used in a process to extract lithium from saline solutions.

The present invention relates to the field of solid materials for adsorption of lithium. In particular, the present invention relates to a novel method for preparing a crystallized and shaped solid material, preferably as extrudates, of formula LiX.sub.x.2Al(OH).sub.3, nH.sub.2O with n being comprised between 0.01 and 10, x being equal to 1 when X is an anion selected from among chloride, hydroxide and nitrate anions, and x being equal to 0.5 when X is an anion selected from among sulfate and carbonate anions, comprising a step a) for precipitation of boehmite under specific temperature and pH conditions, at least one shaping step, preferably by extrusion, said method also comprising a final hydrothermal treatment step, the whole giving the possibility of increasing the adsorption capacity for lithium as well as the adsorption kinetics of the materials obtained as compared with the materials of the prior art when the latter is used in a method for extracting the lithium from saline solutions.

Provided is a production method of a nitride fluorescent material capable of producing a nitride fluorescent material having a higher emission intensity. The production method is for producing a nitride fluorescent material having a composition containing at least one element M.sup.a selected from the group consisting of Sr, Ca, Ba and Mg, at least one element M.sup.b selected from the group consisting of Li, Na and K, at least one element M.sup.c selected from the group consisting of Eu, Ce, Tb and Mn, and Al and N, which includes subjecting a raw material mixture containing elements constituting the composition of the nitride fluorescent material, along with SrF.sub.2 and/or LiF added thereto as a flux, to a heat treatment, wherein the amount of the flux is in a range of 5.0% by mass or more and 15% by mass or less relative to the total amount, 100% by mass of the raw material mixture and the flux.

A method of making silica-layered double hydroxide microspheres having the formula I: (i) wherein, M.sup.z+ and M.sup.y+ are two different charged metal cations; z=1 or 2; y=3 or 4; 0<x<0.9; b is 0 to 10; c is 0 to 10; P>0, q>0, X.sup.n is an anion; with n>0 a=z(1x)+xy2; and the AMO-solvent is an 100% aqueous miscible organic solvent; comprises the steps: (a) contacting silica microspheres and a metal ion containing solution containing metal ions M.sup.z+ and M.sup.y+ in the presence of a base and an anion solution; (b) collecting the product; and (c) optionally treating the product with AMO-solvent and recovering the solvent treated material to obtain the silica-layered double hydroxide microspheres. Preferably, M in the formula I is Li, Mg, Ni or Ca. Preferably, M in formula I is Al. The invention further provides silica-layered double hydroxide microspheres having the formula I. The silica-layered double hydroxide microspheres may be used as catalysts and/or catalyst supports.
(SiO.sub.2).sub.p@{[M.sup.z+.sub.(1-x)M.sup.y+.sub.x(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O.c(AMO-solvent)}.sub.q(I)

A battery including, as a separator, a functional layer including a layered double hydroxide that contains Ni, Al, Ti and Zn, and has an atomic ratio Zn/(Ni+Ti+AI+Zn) of 0.04 or more determined by an energy dispersive X-ray analysis (EDS).

A battery including, as a separator, a functional layer including a layered double hydroxide that contains Ni, Al, Ti and Zn, and has an atomic ratio Zn/(Ni+Ti+AI+Zn) of 0.04 or more determined by an energy dispersive X-ray analysis (EDS).

A method for effectively removing minute impurities of 1 m or less in size that are present on a surface of an aluminum nitride single-crystal substrate without etching the surface includes scrubbing a surface of an aluminum nitride single-crystal substrate using a polymer compound material having lower hardness than an aluminum nitride single crystal, and an alkali aqueous solution having 0.01-1 mass % concentration of potassium hydroxide or sodium hydroxide, the alkali aqueous solution being absorbed in the polymer compound material.

This invention is directed to regeneration of solutions comprising metal ions, and production of valuable hydroxide compounds. Specifically, the invention is related to regeneration of spent electrolyte solutions comprising metal ions (e.g. Al ions), such as electrolyte solutions used in metal/air batteries. The invention is further related to production of layered double hydroxides, and, optionally aluminum tri-hydroxide from aluminate.