Abstract: Alumina particles having average particle size of about 1-20 microns are converted to alpha alumina in a steam-fluidized bed maintained at about 380.degree.-600.degree. C. and a pressure greater than about 1000 psig. Acidifying the steam reduces average crystallite size of the product and lowers content of some impurities. A preferred product is alpha alumina having an average crystallite size of less than about 0.2 micron.

Abstract: Disclosed is a method of making aluminum borate fibers comprising the steps of preparing an aluminum borate gel by reacting aluminum salt in a solution with ammonium borate and heating the gel to form the aluminum borate fibers.

Abstract: A process for producing aluminum hydroxide product having an improved level of whiteness is disclosed. In the process, a caustic solution having dissolved aluminum hydroxide is subjected to purification to remove color producing humate material. Purification includes passing the caustic solution through a semi-permeable membrane. The solution purified of humate material is treated to precipitate aluminum hydroxide therefrom.

Abstract: In a process utilizing steam, the method of producing at least a portion of said steam, including heating a water-containing, solid substance for generating steam and capturing the generated steam for said process. A suitable solid substance is Al(OH).sub.3. New alumina products are obtained.

Abstract: A system is disclosed for the purification of a caustic solution to remove impurities therefrom comprises: bringing the caustic solution into contact under pressure with the outside of a plurality of porous hollow fibers each having at least one open end and coated with a semipermeable membrane and collecting purified solution from the open ends of the hollow fibers. In a preferred embodiment, the filtering medium comprises porous hollow polysulfone fibers coated with a semipermeable sulfonated polysulfone membrane.

Abstract: A process for producing aluminum hydroxide product having an improved level of whiteness is disclosed. In the process, a caustic solution having dissolved aluminum hydroxide is subjected to purification to remove color producing humate material. Purification includes passing the caustic solution through a semi-permeable membrane. The solution purified of humate material is treated to precipitate aluminum hydroxide therefrom.

Abstract: Novel adsorbent and substrate compositions are formed by mixing activated aluminas and synthetic hydrotalcite produced by reacting activated magnesia with an aqueous solution containing aluminate, carbonate, and hydroxyl ions. Activated magnesia used in this method is formed by heating a magnesium compound such as magnesium carbonate or magnesium hydroxide to a temperature between about 500.degree.-900.degree. C. The method is suited to producing synthetic hydrotalcite from industrial Bayer liquor. The synthetic hydrotalcite so formed can be heated to a temperature of about 500.degree.-600.degree. C. to form a highly porous and adsorbent product either before or after mixing with activated aluminas to form the composite of the present invention.

Abstract: Substantially pure boehmite is produced by heating an aqueous sodium aluminate solution to a temperature of about 115.degree.-145.degree. C., preferably about 120.degree.-130.degree. C., treating the heated solution with alumina seed material and separating a boehmite precipitate from the solution. A particularly preferred seed material is boehmite gel.

Abstract: A process for the production of alumina from aluminum-containing mineral ores, such as bauxite, comprising comminuting the aluminum-containing mineral ore, then reacting the comminuted mineral ore at an elevated temperature with an aqueous solution having at least 150 grams per liter of sodium bicarbonate which forms a solid reaction product containing dawsonite and impurities, and finally converting the dawsonite to alumina.

Abstract: The process of the present invention resides in the production of an extremely pure basic aluminum-sodium carbonate of the dawsonite type. In the process of the present invention, aluminum hydroxide is reacted with an aqueous sodium bi-carbonate solution at a temperature between 160.degree. and 240.degree. C. and at a pressure of 5-50 atm. The reagents from an aqueous suspension which is stirred throughout the duration of the reaction and the temperature of the reaction is chosen in accordance with the length of crystalline fiber which is to be produced.