Purification of Bayer process liquors
AssigneesKaiser Aluminum & Chemical Corporation, Nalco Chemical Company
InventorsWilliam J. Roe, John T. Malito
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Abstract
Bayer process liquors derived from the digestion of bauxites with a caustic solution are purified by removing at least a portion of the organic impurities present in the liquors. Removal of these impurities is accomplished by treating liquor containing dispersed therein solids generated by the Bayer process or added thereto, such as red mud particles, alumina trihydrate, oxalate salt, or filter aid with an organic polymeric, water-soluble cationic quaternary ammonium salt (POLYQUAT salt) which due to its cationic nature will adhere to the surface of the dispersed solids. The organic coating or layer adhered to the solids provides a receptive surface for the organic impurities, thus allowing formation of a solid-Polyquat-organic Adduct which is easily removed from the Bayer system.
Claims19
A process of removing humate-type organic impurities from Bayer process liquors and slurries containing dispersed solids therein, said solids generated either by the Bayer process or added thereto, which comprises introducing into the liquor a water-soluble, vinylic cationic polymetric quaternary ammonium salt in an amount sufficient to form at least a partial coating on the dispersed solids, maintaining the coated solids in contact with the liquor for a time sufficient to remove at least a portion of the humate present in the liquor through adhesion of the humate to the coating, removing the coated solids having the adhered humate thereon from the liquor and recovering a liquor having a significantly reduced humate content.
A process of removing humate-type organic impurities from Bayer Process liquors and slurries which comprises adding to said liquors and slurries an effective amount of a water-soluble vinylic cationic polymeric quaternary ammonium salt in the presence of dispersed solids, said solids being generated naturally by the Bayer process or being added thereto, thereby forming a solid-polymeric quaternary ammonium salt-humate impurities coacervated adduct;
- then removing said adduct from the liquors and slurries and recovering a liquor having significantly reduced humate content.
Dependencies are inferred from the claim text.