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OwnerAndrej Vladimirovich KNYAZEV, Aleksandr Aleksandrovich DAMASKIN +2inventors
InventorsAndrej Vladimirovich KNYAZEV, Aleksandr Aleksandrovich DAMASKIN, Anna Aleksandrovna DAMASKINA, Sergej Fedorovich ORDON
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The invention refers to chemical engineering, in particular to a method for production of amorphous aluminium hydroxide and pseudoboehmite-structured aluminium hydroxide, as well as it can be also used for production of pelletised active aluminium oxide, catalysts, carrying agents, and in other industries. The offered method for processing of mud water from alumina production includes: filtration of mud water, its carbonisation via saturation with carbon dioxide, separation of formed residues, their washing by water, and drying. At that, mud water is carbonised in two stages, where: the first carbonisation stage of mud water is carried out up to a pH value of slurry providing precipitation of amorphous aluminium hydroxide, resulting slurry is filtered, and residue is washed to get a product in form of amorphous aluminium hydroxide suitable for application as a modifier of cement mortars and carbonate liquor sent to the second carbonisation stage; the second carbonisation stage is carried out up to a pH value of slurry providing the maximum precipitation quantity of the target residue, resulting slurry is filtered, and residue is washed to get a product in form of pseudoboehmite suitable for application as a precursor in production of aluminium oxide catalyst carriers. The obtained low-cost method for processing of mud water from alumina production allows production of pseudoboehmite-structured aluminium hydroxide powders with low impurity contents from this water and also ensures expansion of the raw material market for production of cement mortars and aluminium oxide catalyst carriers.
Method for processing of mud water from alumina production, which includes:
The method described in Item 1 characterised in that carbonisation of mud water is carried out via bubbling by carbon dioxide-containing gases, where exhaust gases from sintering kilns of aluminium-containing raw materials with limestone and/or soda are used as carbon dioxide-containing gases, and/or gases from lime calcination kilns are used as carbon dioxide-containing gases, and/or gases formed upon combustion of power generating coal or hydrocarbons are used as carbon dioxide-containing gases.
The method described in Item 1 characterised in that the first carbonisation stage is carried out up to a pH value of slurry preferably equal to 11-10.5.
The method described in Item 1 characterised in that resulting slurry after the first carbonisation stage of mud water is filtered until residue in the filter is dried to preferable moisture content of 60-80% wt.
The method described in Item 1 characterised in that the second carbonisation stage is carried out up to a pH value of slurry preferably equal to 9-8.
The method described in Item 1 characterised in that residue after the second carbonisation stage is washed at wash water temperature preferably equal to 40-90° C.
Dependencies are inferred from the claim text.