The present invention provides alumina hydrate particles, a flame retardant and a resin composition that are each for an electric wire/cable covering material improvable in flame retardancy and mechanical properties while the covering material keeps acid resistance; such an electric wire/cable; and producing methods thereof. The alumina hydrate particles of the present invention for electric wire/cable covering material have an average particle size of 0.5 to 2.5 m, and having a primary particle variation R of 24% or less, the variation R being represented by the following expression: primary particle variation R=standard deviation (m) of major axis diameters of the primary particles/average value (m) of the major axis diameters of the primary particles100.

The invention provides highly reactive nano-sized alumina particle compositions, including alumina compositions with a BET surface areas on the order of 2000 m.sup.2/g. Also disclosed are impregnated alumina supports comprising materials that are metal oxides or carbonates. Methods for the synthesis and fabrication of these compositions are provided, along methods for the use of these compositions as sorbents.

A crystalline Boehmite product and a method of forming said product is provided in which the crystalline Boehmite exhibits an average particle size (d50) that is less than 7,000 nanometers. This method comprises preparing an aqueous slurry by mixing together water, large aluminum oxide precursors, a highly dispersible Boehmite grade, and optionally, an organic dispersing agent; adjusting the pH of the slurry; heating the slurry for a predetermined duration of time; collecting the slurry to form a wet cake; and drying the wet cake to obtain the crystalline Boehmite product. The crystalline Boehmite product may be mixed with a plastic resin to form a flame retardant plastic mixture, which can be subjected to a conventional plastic processing method to form a flame retardant composite.

A crystalline Boehmite product and a method of forming said product is provided in which the crystalline Boehmite exhibits an average particle size (d50) that is less than 7,000 nanometers. This method comprises preparing an aqueous slurry by mixing together water, large aluminum oxide precursors, a highly dispersible Boehmite grade, and optionally, an organic dispersing agent; adjusting the pH of the slurry; heating the slurry for a predetermined duration of time; collecting the slurry to form a wet cake; and drying the wet cake to obtain the crystalline Boehmite product. The crystalline Boehmite product may be mixed with a plastic resin to form a flame retardant plastic mixture, which can be subjected to a conventional plastic processing method to form a flame retardant composite.

Provided is a boehmite structure including a plurality of boehmite particles where adjacent boehmite particles are bonded to each other. In the boehmite structure, a boehmite crystallite size is 10 nm or less, and a porosity is 15% or less. Also provided is a method for producing the boehmite structure, including a mixing step of obtaining a mixture by mixing mechanochemically treated hydraulic alumina with a solvent including water, and a pressure heating step of pressurizing and heating the mixture under a condition of a pressure of 10 to 600 MPa and a temperature of 50 to 300 C.

A new method and apparatus is applied to manufacture boehmite and sol gel abrasive grain with greatly reduced raw material cost. The raw material starts from alumina trihydrate, which is transferred to highly dispersible alumina monohydrate under hydrothermal treatment in an agitated zirconium-steel or titanium-steel cladding plate high pressure reactor. Then the highly dispersed and deionized sol is converted to sintered high-density microcrystalline ceramic abrasive grain by sol-gel process.

A boehmite structure includes a plurality of boehmite particles where adjacent boehmite particles are bonded to each other. The boehmite structure has a porosity of 30% or less. A method of producing a boehmite structure includes obtaining a mixture by mixing hydraulic alumina with a solvent including water, and pressurizing and heating the mixture under a condition of a pressure of 10 to 600 MPa and a temperature of 50 to 300 C.

A boehmite structure includes a plurality of boehmite particles where adjacent boehmite particles are bonded to each other. The boehmite structure has a porosity of 30% or less. A method of producing a boehmite structure includes obtaining a mixture by mixing hydraulic alumina with a solvent including water, and pressurizing and heating the mixture under a condition of a pressure of 10 to 600 MPa and a temperature of 50 to 300 C.