Process for producing low-soda alumina, apparatus therefor, and alumina

• Main Authors: KIICHI KIMURA, TAKAYOSHI KOMIYA
• Format: Patent
• Language: English
• Published: 30.10.2008
• Subjects: ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS; CONCRETE; INORGANIC CHEMISTRY; LIME, MAGNESIA; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; REFRACTORIES; SLAG; THEIR RELEVANT APPARATUS; TRANSPORTING; TREATMENT OF NATURAL STONE

A process for producing a low-soda alumina comprising calcining aluminum hydroxide in a calciner in the presence of a soda-removal agent, wherein the alumina dust produced in the calciner is sorted by particle size and collected in a dust collector and at least a portion of the collected alumina dust is subjected to a soda-removal process and is then returned to the calciner. An apparatus for producing a low-soda alumina, comprising a calciner for calcining aluminum hydroxide in the presence of a soda-removal agent, by which alumina dust is produced; a unit connected to the calciner for collecting, by particle size, the alumina dust; a unit for removing soda from a slurry containing at least a portion of the collected alumina dust; and a circuit for returning the soda-removed alumina dust back into the calciner.