Digestion of a laterite with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfateremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over 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 an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The addition of oxalic acid generates insoluble ferrous oxalate which thermally decomposes to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

The invention relates to a method of producing a binder comprising the steps of preparing (20) a residual material comprising amorphous alumina-rich and/or aluminium hydroxide-rich constituents, heating (30) the residual material to produce a fired material, the heating (30) of the residual material being at a temperature of >800 C.

The invention relates to a method of producing a binder comprising the steps of preparing (20) a residual material comprising amorphous alumina-rich and/or aluminium hydroxide-rich constituents, heating (30) the residual material to produce a fired material, the heating (30) of the residual material being at a temperature of >800 C.

A method of manufacturing high-density beads of high-purity alumina, in which general aluminum hydroxide is dissolved in a sodium hydroxide solution. Insoluble impurities are removed to thus manufacture a pure sodium aluminate solution. High-purity aluminum hydroxide is manufactured. The manufactured high-purity aluminum hydroxide is subjected to a hydrothermal reaction, thus removing both crystal water and sodium. Sulfuric acid and ammonia are not used, raw material powder uncontaminated with impurities is manufactured by performing atomization using pulverizing media, and the powder as a raw material and ultrapure water are used to manufacture seeds. While the atomized powder and the ultrapure water are put onto a rotating plate, steps are performed until a desired size is obtained, thus manufacturing highly densified beads. A sintering process is performed in order to maintain a molding shape and to increase a density, followed by a classification process.

A method of manufacturing high-density beads of high-purity alumina, in which general aluminum hydroxide is dissolved in a sodium hydroxide solution. Insoluble impurities are removed to thus manufacture a pure sodium aluminate solution. High-purity aluminum hydroxide is manufactured. The manufactured high-purity aluminum hydroxide is subjected to a hydrothermal reaction, thus removing both crystal water and sodium. Sulfuric acid and ammonia are not used, raw material powder uncontaminated with impurities is manufactured by performing atomization using pulverizing media, and the powder as a raw material and ultrapure water are used to manufacture seeds. While the atomized powder and the ultrapure water are put onto a rotating plate, steps are performed until a desired size is obtained, thus manufacturing highly densified beads. A sintering process is performed in order to maintain a molding shape and to increase a density, followed by a classification process.

A method of producing a high-purity nano alumina powder, in which general aluminum hydroxide is dissolved in a sodium hydroxide solution to give a sodium aluminate solution, most insoluble impurities other than sodium are removed using a micro filter to give a pure sodium aluminate solution. A seed is added thereto so as to precipitate nano aluminum hydroxide as a nano slurry under optimal precipitation conditions. The nano aluminum hydroxide slurry is filtered, dried, disintegrated, and then calcined at a low temperature of 900 C. or less, thus achieving the mass production of high-purity nano alumina having a particle size of 200 nm or less, whereby high-purity alumina nanoparticles can be produced in an environmentally friendly manner at low cost.

Disclosed are novel aqueous aluminum complex compositions and methods of making and using them. The novel compositions comprise very low halide content, even when made from aluminum chlorohydrate. The compositions find use in the production of zeolites, coatings, abrasives, binders, and refractories; and in the treatment of wastewater for example. The methods of making the novel compositions include passing a first aqueous aluminum complex composition through an anion exchange column or otherwise contacting the first composition with the anion exchange resin to provide a second aqueous aluminum complex composition that is different from the first aqueous aluminum complex composition. Also disclosed are methods of making zeolites and aqueous silica-alumina compositions from the novel aqueous aluminum complex compositions.

A method of reducing the ammonia emission from an aluminium oxide comprises the step of contacting secondary aluminium oxide with a zeolite. Preferably the zeolite is a used or unused fluid catalytic cracking (FCC) catalyst such as zeolite Y. The invention also relates to a mixture comprising secondary aluminium oxide and a zeolite, wherein the zeolite is a used or unused fluid catalytic cracking (FCC) catalyst and that the composition has a gaseous ammonia emission of 1 mg NH.sub.3 per gram of composition and hour. Lastly, the invention is directed towards the use of a zeolite for reducing the ammonia emission from secondary aluminium oxide.

A method of reducing the ammonia emission from an aluminium oxide comprises the step of contacting secondary aluminium oxide with a zeolite. Preferably the zeolite is a used or unused fluid catalytic cracking (FCC) catalyst such as zeolite Y. The invention also relates to a mixture comprising secondary aluminium oxide and a zeolite, wherein the zeolite is a used or unused fluid catalytic cracking (FCC) catalyst and that the composition has a gaseous ammonia emission of 1 mg NH.sub.3 per gram of composition and hour. Lastly, the invention is directed towards the use of a zeolite for reducing the ammonia emission from secondary aluminium oxide.

The invention provides a method of inhibiting the accumulation of DSP scale in the liquor circuit of Bayer process equipment. The method includes adding one or more particular silane based small molecules to the liquor fluid circuit. These scale inhibitors reduce DSP scale formation and thereby increase fluid throughput, increase the amount of time Bayer process equipment can be operational and reduce the need for expensive and dangerous acid washes of Bayer process equipment. As a result, the invention provides a significant reduction in the total cost of operating a Bayer process.