Abstract: The present invention provides an improved process for the preparation of MgO of high purity >99% from salt bitterns via intermediate formation of Mg(OH)2 obtained from the reaction of MgCl2 and lime, albeit indirectly, i.e., MgCl2 is first reacted with NH3 in aqueous medium and the slurry is then filtered with ease. The resultant NH4Cl-containing filtrate is then treated with any lime, to regenerate NH3 while the lime itself gets transformed into CaCl2 that is used for desulphatation of bittern so as to recover carnallite and thereafter MgCl2 of desired quality required in the present invention. The crude Mg(OH)2 is dried and calcined directly to produce pure MgO, taking advantage of the fact that adhering impurities in the Mg(OH)2 either volatilize away or get transformed into the desired product, i.e., MgO.

Abstract: Magnesium oxychloride cement is formed by mixing a magnesium chloride (MgCl2) brine solution with a magnesium oxide (MgO) composition in a selected stoichiometric ratio of MgCl2, MgO, and H2O that forms the 5 phase magnesium oxychloride cement composition. Although Sorel cements formed from the mixture of MgCl2, MgO can form a variety of compounds, the inventive systems and methods provide for controlling the cement kinetics to form the five phase magnesium oxychloride cement composition and results in an improved and stable cement composition. Various fillers can be optionally added to form preferred cement materials for uses as diverse such as road stripping, fire-proofing, fire barriers, cement repair, and mortar.

Abstract: A method to prevent build-up of limestone in a slaker that is used for batchwise slaking of burnt lime is described, in which lime slurry is produced with a greater degree of fineness and prolonged sedimentation time, where for immediate cleansing of the slaker before next slaking, after said calibration of the load cell aggregate, a number of valves are opened for given time periods for addition of flushing water to respective nozzles, in that flushing water is supplied sequentially via each valve to associated nozzle(s), until a predetermined amount of flushing water is reached in the slaker.

Abstract: The object is to provide a high-purity magnesium oxide particle aggregate that is redispersible and can be supplied with keeping high purity, and a method for producing the same. A magnesium oxide particle aggregate that is an aggregate of magnesium oxide particles, wherein the magnesium oxide particles have an average particle size of 1 ?m or less, and comprises Si, Al, Ca, Fe, V, Cr, Mn, Ni, Zr, B and Zn as impurities in their respective amounts of 10 ppm by mass or less, wherein the total amount of the impurities is 100 ppm by mass or less.

Abstract: A method for preparing metal compound nanoparticles, comprising treating a uniform dispersion of at least one metal precursor in an organic solvent with a supercritical carbon dioxide fluid to attain a homogeneous mixture, which is subjected to a solvothermal reaction under a subcritical CO2 condition, makes it easy to prepare nanoparticles of a metal oxide, a doped metal compound, or a metal complex having various shapes.

Abstract: The present invention relates to a trifunctional catalyst used in catalytic cracking device in petroleum refining industry and a method for preparing the same. The trifunctional catalyst of the invention comprises absorbent, cerium dioxide and vanadium pentoxide acting as oxidative catalyst and cerium oxyfluoride acting as structural promoter. The oxidative catalyst and structural promoter are dispersed over the absorbent. The absorbent is spinel-based composite oxides having a general formula of MgAl2-xFexO4.yMgO, where the x is 0.01-0.5 and y is 0.2-1.2. In the trifunctional catalyst, the raw material for forming the chemical compound containing rare-earth cerium is hamartite powder. The method for preparing the trifunctional catalyst of the invention is shown as follows: the components relating to the preparation of the finished product are dissolved or dispersed into liquid materials; then the trifunctional catalyst is obtained after the mixing, drying and calcining of such liquid materials.

Abstract: Disclosed is a processes for the production of relatively high purity alkaline earth metal oxides, such as SrO, from relatively low purity forms of carbonated or other oxygenated forms of such metals, such as strontium carbonate. The relatively low purity material is exposed to conditions under which at least a portion of the metal contained therein is converted to a salt that is more readily solvated in a provided solvent than the starting material, while at the same time not substantially increasing the solubility of at least one or more of the impurities in such selected solvent. This step is then preferably followed by removal of solid or otherwise un-dissolved impurities from the solution. After the removal step, the solution is preferably exposed to conditions effective to form a relatively insoluble salt of the alkaline earth metal, such as a strontium salt. The insoluble salt is also preferably one that can be readily and effectively converted to the desired alkaline earth metal oxide, preferably SrO.

Abstract: In a method and an apparatus for forming metal oxide on a substrate, a source gas including metal precursor flows along a surface of the substrate to form a metal precursor layer on the substrate. An oxidizing gas including ozone flows along a surface of the metal precursor layer to oxidize the metal precursor layer so that the metal oxide is formed on the substrate. A radio frequency power is applied to the oxidizing gas flowing along the surface of the metal precursor layer to accelerate a reaction between the metal precursor layer and the oxidizing gas. Acceleration of the oxidation reaction may improve electrical characteristics and uniformity of the metal oxide.

Abstract: Magnesium hydroxide nanoparticles are made from a magnesium compound that is reacted with an organic dispersing agent (e.g., a hydroxy acid) to form an intermediate magnesium compound. Magnesium hydroxide nanoparticles are formed from hydrolysis of the intermediate compound. The bonding between the organic dispersing agent and the magnesium during hydrolysis influences the size of the magnesium hydroxide nanoparticles formed therefrom. The magnesium hydroxide nanoparticles can be treated with an aliphatic compound (e.g., a monofunctional alcohol) to prevent aggregation of the nanoparticles during drying and/or to make the nanoparticles hydrophobic such that they can be evenly dispersed in a polymeric material. The magnesium hydroxide nanoparticles exhibit superior fire retarding properties in polymeric materials compared to known magnesium hydroxide particles.

Abstract: Magnesium hydroxide having a large specific surface area is provided. A magnesium-containing matter is chemically decomposed by a solution of acid, and a primary solution of alkali with weak alkalinity is obtained by adding a solution of alkali to the solution of acid, and impurities contained in the primary solution of alkali are eliminated, and a secondary solution of alkali with strong alkalinity is obtained by adding a solution of alkali to the primary solution of alkali, and successively a magnesium hydroxide is deposited in secondary solution of alkali.

Abstract: The invention relates to fine-particled alkaline-earth titanates and to a method for the production thereof by reacting alkaline-earth metal compounds with titanium dioxide particles. The titanium dioxide particles have a BET-surface greater than 50 m2/g. The titanium dioxide particles can have a very low sulphate, chloride and carbon content. The reaction can take place at a temperature below 700° C. The alkaline-earth titanate can have a BET-surface of 5-100 m2/g. Advantageously, it does not contain any hydroxyl groups in the crystal lattice. The alkaline-earth titanate can be used in the production of microelectronic components.

Abstract: The present invention relates to methods of producing surface-modified nanoparticulate particles at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide, and aqueous suspensions of these particles. The invention further relates to the surface-modified nanoparticulate particles, obtainable by these methods, at least of one metal oxide, metal hydroxide and/or metal oxide hydroxide and aqueous suspensions of these particles, and to their use for cosmetic sunscreen preparations, as stabilizer in plastics and as antimicrobial active ingredient.

Abstract: Process for preparing a metal oxide powder, in which starting materials are evaporated and oxidized, wherein a metal melt in the form of droplets and one or more combustion gases are fed to the evaporation zone of a reactor, where the metal melt is evaporated completely under nonoxidizing conditions, subsequently, the mixture flowing out of the evaporation zone is reacted in the oxidation zone of this reactor with a stream of a supplied oxygen-containing gas whose oxygen content is at least sufficient to oxidize the metal and the combustion gases completely.

Abstract: The present invention relates to a method for producing a metal oxide by heating a porous metal-organic framework material, the framework material comprising at least one at least bidentate organic compound bound to at least one metal ion by coordination, and the metal ion being selected from the metals comprising groups to 4 and 13 of the Periodic Table of the Elements, above the complete decomposition temperature of the framework material, and also to metal oxides obtainable by this method, and to the use thereof.

Abstract: Periclase MgO having a nanosheet structure. The distance of the lattice planes in HRTEM is ?0.24 nm-0.25 nm. Method of preparing periclase MgO having a nanosheet structure including preparation of Mg(OCH3)2 in methanol solution. 4-methoxy benzy alcohol (MBZ) or 4-nitro benzyl alcohol (NBZ) or a mixture thereof is added in a ration of Mg to MBZ and/or NBZ of at least 1. Water/methanol mixture is added to the system. Solvent removal and calcinations in air is performed of the mixture.

Abstract: Granular calcium oxide and calcium hydroxide which are highly reactive with a halide gas and its decomposition products and favorably employable for filling a gas-fixing unit (32) of an apparatus (3) for fixing a halide gas are, respectively, a granule of porous spherical calcium oxide particles, which has a BET specific surface area of 50 m2/g or more and a total pore volume of pores having a diameter of 2-100 nm in the range of 0.40-0.70 mL/g and a granule of porous spherical calcium hydroxide particles which has a BET specific surface area of 20 m2/g or more and a total pore volume of pores having a diameter of 2-100 nm in the range of 0.25-0.40 mL/g.

Abstract: Novel magnesium hydroxide flame retardants, a method of making them from a slurry, and their use.

Abstract: An activated lime for use in removing acid gases from a combustion gas stream is produced by thermally decomposing calcium hydroxide to calcium oxide through contact or the calcium hydroxide with a heated gas stream at a temperature or between 750-950° F. for a time sufficient to produce a calcium oxide having a specific surface area of between 30-48 square meters per gram, and collecting the product so produced.

Abstract: The invention relates to nanoscale rutile or oxide powder that is obtained by producing amorphous TiO2 by mixing an alcoholic solution with a titanium alcoholate and with an aluminum alcohalate and adding water and acid. The amorphous, aluminum-containing TiO2 is isolated by removing the solvent, and is redispersed in water in the presence of a tin salt. Thermal or hydrothermal post-processing yields rutile or oxide that can be redispersed to primary particle size. The n-rutile or the obtained oxide having a primary particle size ranging between 5 and 20 nm can be incorporated into all organic matrices so that they remain transparent. Photocatalytic activity is suppressed by lattice doping with trivalent ions. If the amorphous precursor is redispersed in alcohol, or not isolated, but immediately crystallized, an anatase is obtained that can be redispersed to primary particle size.

Abstract: The invention provides a process for preparing a metal hydroxide comprising the steps of: (a) providing particles of a metal silicate; (b) mixing the particles with a mineral acid solution to obtain a slurry which comprises precipitated silica; (c) separating the precipitated silica from the slurry to obtain a remaining solution; (d) increasing the pH of the remaining solution to such an extent that a metal hydroxide is formed; (e) separating the metal hydroxide so obtained from the remaining solution; and (f) adding to the remaining solution obtained in step (e) an acid solution, thereby forming a salt containing solution, or (g) removing at least part of the base added in step (d) from the remaining solution obtained in step (e), thereby forming a salt containing solution.

Abstract: Process for preparing mixed metal oxide powders Abstract Process for preparing a mixed metal oxide powder, in which oxidizable starting materials are evaporated in an evaporation zone of a reactor and oxidized in the vaporous state in an oxidation zone of this reactor, the reaction mixture is cooled after the reaction and the pulverulent solids are removed from gaseous substances, wherein at least one pulverulent metal, together with one or more combustion gases, is fed to the evaporation zone, the metal is evaporated completely in the evaporation zone under nonoxidizing conditions, an oxygen-containing gas and at least one metal compound are fed, separately or together, in the oxidation zone to the mixture flowing out of the evaporation zone, the oxygen content of the oxygen-containing gas being at least sufficient to oxidize the metal, the metal compound and the combustion gas completely.

Abstract: A ceramic powder having a perovskite structure is manufactured by synthesizing a ceramic powder by a dry synthesis process and then heat-treating the synthesized ceramic powder in a solution. The dry synthesis method includes a solid phase synthesis method, an oxalate method, a citric acid method and a gas phase synthesis method.

Abstract: It is an object to provide a method for producing stable alkaline metal oxide sols having a uniform particle size distribution. The method comprises the steps of: heating a metal compound at a temperature of 60° C. to 110° C. in an aqueous medium that contains a carbonate of quaternary ammonium; and carrying out hydrothermal processing at a temperature of 110° C. to 250° C. The carbonate of quaternary ammonium is (NR4)2CO3 or NR4HCO3 in which R represents a hydrocarbon group, or a mixture thereof. The metal compound is one, or two or more metal compounds selected from a group of compounds based on a metal having a valence that is bivalent, trivalent, or tetravalent.

Abstract: A method for the production of Mg(OH)2 nanoparticles, by means of polyol-mediated synthesis, from an Mg precursor as well as a base. The particles produced with this method have a diameter between 10 nm to 300 nm, have a mono-disperse particle distribution, and are present in non-agglomerated form. They can be converted to MgO particles by means of calcination.

Abstract: A method of producing high purity nanoscale powders in which the purity of powders produced by the method exceeds 99.99%. Fine powders produced are of size preferably less than 1 micron, and more preferably less than 100 nanometers. Methods for producing such powders in high volume, low-cost, and reproducible quality are also outlined. The fine powders are envisioned to be useful in various applications such as biomedical, sensor, electronic, electrical, photonic, thermal, piezo, magnetic, catalytic and electrochemical products.

Abstract: The invention provides a submicron magnesium hydroxide particulate composition comprising a first distribution of magnesium hydroxide particles having a D50 of no more than about 0.30 ?m, a D90 of no more than about 1.5 ?m, and a BET surface area of at least about 35 m2/g, which can be used as a flame-retardant additive for synthetic polymers, optionally in combination with other flame-retardant additives such as nanoclays and larger-sized magnesium hydroxide particulate compositions. Polymeric resins comprising the submicron magnesium hydroxide particles and methods of manufacturing submicron magnesium hydroxide particles are also provided.

Abstract: Methods and systems for processing metal oxides from metal containing solutions. Metal containing solutions are mixed with heated aqueous oxidizing solutions and processed in a continuous process reactor or batch processing system. Combinations of temperature, pressure, molarity, Eh value, and pH value of the mixed solution are monitored and adjusted so as to maintain solution conditions within a desired stability area during processing. This results in metal oxides having high or increased pollutant loading capacities and/or oxidation states. These metal oxides may be processed according to the invention to produce co-precipitated oxides of two or more metals, metal oxides incorporating foreign cations, metal oxides precipitated on active and inactive substrates, or combinations of any or all of these forms.

Abstract: The present invention is directed to novel sol-gel methods in which metal oxide precursor and an alcohol-based solution are mixed to form a reaction mixture that is then allowed to react to produce nanosized metal oxide particles. The methods of the present invention are more suitable for preparing nanosized metal oxide than are previously-described sol-gel methods. The present invention can provide for nanosized metal oxide particles more efficiently than the previously-described sol-gel methods by permitting higher concentrations of metal oxide precursor to be employed in the reaction mixture. The foregoing is provided by careful control of the pH conditions during synthesis and by ensuring that the pH is maintained at a value of about 7 or higher.

Abstract: The invention provides a method for the formation of small-size metal oxide particles, comprising the steps of: a) preparing a starting aqueous solution comprising at least one of metallic ion and complexes thereof, at a concentration of at least 0.1% w/w of the metal component; b) preparing a modifying aqueous solution having a temperature greater than 50° C.; c) contacting the modifying aqueous solution with the starting aqueous solution in a continuous mode in a mixing chamber to form a-modified system; d) removing the modified system from the mixing chamber in a plug-flow mode; wherein the method is characterized in that: i) the residence time in the mixing chamber is less than about 5 minutes; and iii) there are formed particles or aggregates thereof, wherein the majority of the particles formed are between about 2 nm and about 500 nm in size.

Abstract: The invention discloses methods for making micron/nano meter sized particles of various inorganic materials such as minerals/oxides/sulphides/metals/ceramics at a steadily expanding liquid-liquid interface populated by suitable surfactant molecules that spontaneously organize themselves into superstructures varying over large length-scales. This experiment is realized in a radial Hele-Shaw cell where the liquid-liquid interfacial growth rate and consequently time scales such as arrival of surfactant molecules to the interface, the hydrodynamic flow effect to modulate the material organization into super structures at the dynamic charged interface.

Abstract: Process for manufacturing an electrochemical device including a cathode, an anode and at least one electrolyte membrane disposed between the anode and the cathode, wherein at least one of the cathode, the anode and the electrolyte membrane, contains at least a ceramic material.

Abstract: A method for the production of Mg(OH)2 nanoparticles, by means of polyol-mediated synthesis, from an Mg precursor as well as a base. The particles produced with this method have a diameter between 10 nm to 300 nm, have a mono-disperse particle distribution, and are present in non-agglomerated form. They can be converted to MgO particles by means of calcination.

Abstract: Calcium carbonate with high brightness is prepared by treating calcium carbonate and/or the milk of lime used for its preparation by reacting milk of lime with carbon dioxide and/or at least one of the calcium-containing preliminary products used for the preparation of the milk of lime before, during and/or after this reaction with a bleaching agent which comprises at least one compound of the formula (I): A[(CR1R2)SOpM(1/q)]r??(I) where the variables have the following meanings: A is NR3R4, NR3, N or OH; R1, R2, R3, R4 independently of one another, are hydrogen or an organic radical; M is ammonium or metal p is 2 or 3; q is the valency of M; and r is 1 when A = OH or NR3R4, is 2 when A = NR3 and is 3 when A = N; and where variables, if a mixture of compounds is used and/or r=2 or 3, are chosen independently of one another for each individual compound and/or for each [(CR1R2)SOpM(1/q)] group.

Abstract: Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

Abstract: A method is shown for producing food grade hydrated lime. A source of raw, hydrated lime is first passed through a classification step which divides the raw hydrated lime into a first fine stream and a first coarse stream. The first fine stream is passed through a further separation step and, without being recombined with the first coarse stream is separated out to form a very fine sized product which meets CODEX chemical specifications. The additional separation step may be a wet process and may utilize a hydrocyclone type separator.

Abstract: A process for leaching a value metal from oxidic materials, such as a lateritic nickel ore, comprising the step of leaching the ore with a lixiviant comprising a cationic salt (e.g., magnesium chloride) and hydrochloric acid is disclosed. An oxidant or additional metal chloride (such as that which results from the leaching operation) may be added. In one embodiment, the process comprises recovery of a value metal from ore comprising the steps of: leaching the ore with a lixiviant; separating a value metal-rich leachate from the ore in a first solid-liquid separation; oxidizing and neutralizing the value metal-rich leachate so obtained; and separating a solution of magnesium chloride from the leachate so obtained in a second solid-liquid separation. In another embodiment, the lixiviant solution is regenerated from the solution of magnesium chloride. In a further embodiment, regeneration of the lixiviant solution includes a step of producing magnesium oxide from the solution of magnesium chloride.

Abstract: The present invention provides a method of removing spectator ions and contaminants from aqueous suspensions of solid particles. In accordance with the method of the invention, the solid particles are transported across a phase boundary into a non-polar organic solvent, leaving the spectator ions and contaminants in the aqueous phase. To facilitate the efficient transportation of the solid particles across the phase boundary, the surface of the solid particles is coated with an amphiphilic polyelectrolyte. If desired, the solid particles can be recovered from the organic phase by evaporating the organic solvent.

Abstract: A process of reacting a metal chloride, especially chromium (III) chloride, with an alkali metal oleate at a temperature of from about 30° to about 300° C., and especially at about 70±1° C., in a solvent to form a metal oleate complex, especially a chromium-oleate complex, and reacting the complex with oleic acid at a reaction temperature of about 300° C. or above in a solvent having a boiling point of higher than the reaction temperature, and precipitating and isolating metal oxide nanocrystals, especially chromium (III) oxide nanocrystals, which are useful as a catalyst in hydrofluorination reactions. Other metal oxide nanocrystals produced by this process include nanocrystals of vanadium oxide, molybedenum oxide, rhodium oxide, palladium oxide, ruthenium oxide, zirconium oxide, barium oxide, magnesium oxide, and calcium oxide are also synthesized by similar process scheme using their respective chloride precursors.

Abstract: Described is a method for the production of metal oxides by flame spray pyrolysis, in particular mixed metal oxides such as ceria/zirconia, and metal oxides obtainable by said method. Due to high enthalpy solvents with a high carboxylic acid content said metal oxides have improved properties. For example ceria/zirconia has excellent oxygen storage capacity at high zirconium levels up to more than 80% of whole metal content.

Abstract: The present invention provides methods and apparatus for treating flue gas containing sulfur dioxide using a scrubber, and more particularly relates to recovering gypsum and magnesium hydroxide products from the scrubber blowdown. The gypsum and magnesium hydroxide products are created using two separate precipitation reactions. Gypsum is crystallized when magnesium sulfate reacts with calcium chloride. Magnesium hydroxide is precipitated when magnesium chloride from the gypsum crystallization process reacts with calcium hydroxide. The process produces a high quality gypsum with a controllable pH and particle size distribution, as well as high quality magnesium hydroxide.

Abstract: Disclosed is a process for making surfactant capped nanocrystals of metal oxides which are dispersable in organic solvents. The process comprises decomposing a metal cupferron complex of the formula MXCupX, wherein M is a metal, and Cup is a N-substituted N-Nitroso hydroxylamine, in the presence of a coordinating surfactant, the reaction being conducted at a temperature ranging from about 150 to about 400° C., for a period of time sufficient to complete the reaction. Also disclosed are compounds made by the process.

Abstract: The present invention is concerned with a method for extracting selectively a metal from a metal mixture in the gaseous phase. The method comprises heating the metal mixture to vaporize the metal; condensing the metal contaminants present in the vapor; reacting any contaminants remaining in the vapor with a reagent to precipitate the remaining contaminants, and collecting the purified metal.

Abstract: A method is shown for producing food grade hydrated lime. A source of raw, hydrated lime is first passed through a classification step which divides the raw hydrated lime into a first fine stream and a first coarse stream. The first coarse stream is then passed to a grinder which produces a ground coarse product. The first fine stream is separated out from the first coarse stream and, without combining the first fine stream with the first coarse stream or with the ground coarse product, is removed to produce a very fine sized product which meets CODEX chemical specifications.

Abstract: The invention provides a method treating acid raw water including the step of neutralising the water by adding calcium carbonate to it in a neutralising stage. The neutralised water is then rendered alkaline or more alkaline by adding an alkali thereto selected from calcium hydroxide, calcium oxide and mixtures thereof in a lime treatment stage. The alkaline water is then treated with carbon dioxide in a carbon dioxide treatment stage, with the carbon dioxide reacting in the carbon dioxide treatment stage with calcium hydroxide dissolved in the water.

Abstract: In a waste wire harness including electric wires each coated with a resin comprised of an olefin-based resin and magnesium hydroxide as a fire retardant, and including accompanied members having at least one of terminals, connectors, various kind of boxes such as junction boxes and fuse boxes, tapes, tubes, grommets, wiring clips, and protectors, a method for recycling the waste wire harness includes a step of removing the accompanied members from the waste wire harness, a step of crushing the waste wire harness after removing the accompanied members to obtain crushed particles, a step of incinerating the crushed particles to produce incinerated ash, a step of converting a magnesium compound contained in the incinerated ash into magnesium hydroxide, and a step of collecting the magnesium hydroxide.

Abstract: A method of producing fine particles of an oxide of a metal, comprising the steps of: preparing an acidic solution which contains ions of the metal; precipitating fine particles of a hydroxide of the metal by adding an alkaline solution to the acidic solution; collecting the fine particles of the hydroxide of the metal precipitated in a mixed solution of the acidic solution and the alkaline solution; mixing fine particles of a carbon with the collected fine particles of the hydroxide of the metal; and heat-treating a mixture of the fine particles of the hydroxide of the metal and the fine particles of the carbon at a predetermined temperature in a non-reducing atmosphere, whereby the fine particles of the oxide of the metal are produced.

Abstract: The present invention relates to a single step process for the synthesis of nanoparticles of phase pure ceramic oxides of a single or a multi-component system comprising one or more metal ions. The process comprises preparing a solution containing all the required metal ions in stoichiometric ratio by dissolving their respective soluble salts in an organic solvent or in water, preparing a precursor, adjusting the nitrate/ammonia content in the system, and heating the system.

Abstract: Provided are magnesium hydroxide particles having a hexagonal crystal form and having an aspect ratio (H) which satisfies the following expression (I), 0.45·A·B<H<1.1·A·B  (I) (wherein H is an aspect ratio, A is an average secondary particle diameter (&mgr;m) of all of the particles measured by a laser diffraction scattering method and B is a specific surface area (m2/g) of all of the particles measured by a BET method), a flame-retardant comprising the particles, a flame-retardant resin composition comprising 100 parts by weight of a synthetic resin and a 5 to 300 parts by weight of the magnesium hydroxide particles, and a molded article therefrom. The magnesium hydroxide particles are hexagonal single crystals, the hexagonal form thereof are not necessarily required to be regular hexagonal, and the size thereof are not necessarily constant.

Abstract: Calcium hydroxide in which the average secondary particle diameter at a cumulative percentage of 50% by number in a particle size distribution is 2.0 &mgr;m or less and the BET specific surface area is 7 to 20 m2/g and which is surface-treated with 0.1 to 10% by weight of an anionic surfactant, its production process and its use.

Abstract: The present invention is directed to a process for the preparation of crystalline anionic clay-containing bodies from sources comprising an aluminum source and a magnesium source comprising the steps of: a) preparing a precursor mixture, b) shaping the precursor mixture to obtain shaped- bodies, c) optionally thermally treating the shaped bodies, and d) aging to obtain crystalline anionic clay-containing bodies. The quintessence of the present invention is that the bodies are shaped prior to the forming of the crystalline anionic clay in said bodies. This results in very attrition resistant bodies, without the need to add a binder material.