Additives can be added to fertilizers to impart desirable characteristics. For example, a class of additives have been disclosed to stabilize the explosive potential of AN fertilizers are desirable, however, such additives can react with the AN fertilizer during its manufacture or during its storage. This is particularly the case where the additives contain carbonates, oxides, hydroxides, contain water of hydration or water locked within the structure (e.g. within an interlayer substructure). This reaction can be avoided if the additive has a passivation layer substantially covering the surface of the additive. The passivation layer, being substantially non-reactive and substantially insoluble, protects the additive so that the additive keeps its desired properties and the fertilizer keeps its quality. In other aspects, methods of making the fertilizer are provided.

The present invention relates to a process for modifying a layered double hydroxide (LDH), the process comprising, a. providing a water-wet layered double hydroxide of formula:

[M.sup.z+.sub.1-xM.sup.y+.sub.x].sup.a+(X.sup.n).sub.a/r.bH.sub.2O (1) wherein M and M are metal cations, z=1 or 2; y=3 or 4, x is 0.1 to 1, preferably x<1, more preferably x=0.1-0.9, b is greater than 0 to 10, X is an anion, r is 1 to 3, n is the charge on the anion X and a is determined by x, y and z, preferably a=z(1-x)+xy-2; b. maintaining the layered double hydroxide water-wet, and c. contacting the water-wet layered double hydroxide with at least one solvent, the solvent being miscible with water and preferably having a solvent polarity (P) in the range 3.8 to 9,
as well as to a layered double hydroxide prepared according to that process.

The present invention relates to a process for modifying a layered double hydroxide (LDH), the process comprising, a. providing a material comprising a layered double hydroxide of formula: [M.sup.z+.sub.1-xM.sup.y+.sub.x(OH).sub.2].sup.q+(X.sup.n).sub.q/n.bH.sub.2O wherein M and M are metal cations, z is 1 or 2, x is 0.1 to 1, b is 0 to 5, y is 3 or 4, X is an anion, n is 1 to 3 and q is determined by x, y and z, b. optionally washing the material at least once with a mixture of water and a mixing solvent miscible with water, and c. washing the material obtained in step a or b at least once with at least one first solvent, the first solvent being miscible with water and having a solvent polarity P.

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.(1x)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)

The present invention relates to a process for modifying a layered double hydroxide (LDH), the process comprising, a. providing a water-wet layered double hydroxide of formula:
[M.sup.z+.sub.1-xM.sup.y+.sub.x(OH).sub.2].sup.a+(X.sup.n).sub.a/r.bH.sub.2O(1) wherein M and M are metal cations, z=1 or 2; y=3 or 4, x is 0.1 to 1, preferably x<1, more preferably x=0.1-0.9, b is 0 to 10, X is an anion, r is 1 to 3, n is the charge on the anion X and a is determined by x, y and z, preferably a=z(1x)+xy2; b. maintaining the layered double hydroxide water-wet, and c. contacting the water-wet layered double hydroxide with at least one solvent, the solvent being miscible with water and preferably having a solvent polarity (P) in the range 3.8 to 9,
as well as to a layered double hydroxide prepared according to that process.

Layered double hydroxides having a high surface area (at least 125 m.sup.2/g) and the formula (I)
[M.sup.z+.sub.1?xM.sup.y+.sub.x(OH).sub.2].sup.a+(X.sup.n?).sub.a/n.sub.+bH.sub.2O.c(AMO-solvent)(I)
wherein M and M are different and each is a charged metal cation (and must be present), z=1 or 2; y=3 or 4, 0<x<0.9, b is 0 to 10, c=0 to 10, X is an anion, n is the charge on the anion, and a=z(1?x)+xy?2; AMO-solvent is aqueous miscible organic solvent, may be prepared by a method which comprises a) precipitating a layered double hydroxide having the formula
[M.sup.z+.sub.1?xM.sup.y+.sub.x(OH).sub.2].sup.a+(X.sup.n?).sub.a/n.sub.+bH.sub.2O wherein M, M, z, y, x, a, b and X are as defined above from a solution containing the cations of the metals M and M and the anion X.sup.n?; b) ageing the layered double hydroxide precipitate obtained in step a) in the original solution; c) collecting, then washing the layered double hydroxide precipitate; d) dispersing the wet layered double hydroxide in an AMO solvent so as to produce a slurry of the layered double hydroxide in the solvent; e) maintaining the dispersion obtained in step d); and f) recovering and drying the layered double hydroxide. The high surface area products have low particle size and are particularly suitable for use as catalysts, catalyst supports, sorbents and coatings.

A magnetic hydrotalcite composite which is useful in fields such as wastewater treatment, ultraviolet absorption, electromagnetic wave absorption and acid gas absorption, and a production method thereof. The magnetic hydrotalcite composite comprises an inner layer and an outer layer, in which the inner layer is made of a hydrotalcite compound and the outer layer is made of a ferrite compound.

The present invention relates to a method for extracting magnesium and lithium and also producing layered double hydroxides (LDH) from brine, comprising the steps of: adding an aluminum salt to brine, to prepare a mixed salt solution A for preparing MgAl-LDH; adding an alkaline solution to carry out co-precipitation, followed by crystallization; after the crystallization is complete, performing solid-liquid separation to obtain a solid product of MgAl-LDH and a filtrate; concentrating the filtrate by evaporation to obtain a lithium-rich brine, adding an aluminum salt thereto to prepare a mixed salt solution B for preparing LiAl-LDH; adding the mixed salt solution B to an alkaline solution to carry out precipitation; after the precipitation is complete, performing solid-liquid separation to obtain a solid product of LiAl-LDH and a filtrate; and concentrating the filtrate by evaporation, returning the solution concentrated by evaporation to the lithium-rich brine for recycled use. This method uses mild reaction and simple equipment, has a small loss of Li, can achieve isolation of resources from salt lakes, and can also obtain functional materials having a high added value.

The present invention provides a layered double hydroxide with improved conductivity, a layered double hydroxide and a composite material containing the layered double hydroxide. The layered double hydroxide is represented by the general formula: [Mg.sup.2+.sub.(1-y)M1.sup.+.sub.y].sub.1-x[Al.sup.3+.sub.(1-z)M2.sup.+.sub.z].sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O, wherein 0.1x0.4, 0y0.95, and 0z0.95, provided that both y and z are not 0 at the same time; =1 or 2; =2 or 3; A.sup.n is an n-valent anion, provided that n is an integer of 1 or greater; m0; M1.sup.+ is a cation of at least one substituent element selected from monovalent elements, transition metal elements, and other elements with an ionic radius greater than that of Mg.sup.2+; and M2.sup.+ is a cation of at least one element selected from divalent elements, transition metals, and other elements with an ionic radius greater than that of Al.sup.3+.

To improve the thermal stability of a brominated polymer type flame retardant in a flame-retardant resin composition containing a styrene-based resin and the brominated polymer type flame retardant to provide a flame-retardant resin molded article in which occurrences of black foreign substances and discoloration decrease. The flame-retardant resin composition contains a styrene-based resin, a brominated polymer type flame retardant, an epoxy compound, and a halogen capture agent, wherein a content of bromine is 18 to 42% by mass.