| 摘要 |
FIELD: chemistry. ^ SUBSTANCE: method has three versions. In the first version, an aqueous solution of aluminium, alkali and alkali-earth metal salts of carboxylic acids is neutralised with basic agents to obtain a suspension containing an aqueous solution of alkali and alkali-earth metal salts of carboxylic acids and a precipitate having formula Al(OH)xAcy, where Ac is an anionic carboxylic acid residue, x=0.1-3.0, y=2.9-0.0. The obtained precipitate is separated from the aqueous solution. In the second version, an aqueous solution of aluminium, alkali and alkali-earth metal salts of carboxylic acids is evaporated to obtain a suspension containing an aqueous solution of alkali and alkali-earth metal salts of carboxylic acids and a precipitate having formula Al(OH)xAcy, where Ac is a carboxylic acid residue, x=0.1-1.5, y=2.9-1.5. The obtained precipitate is separated from the aqueous solution. In the third version, an aqueous solution of aluminium salts of carboxylic acids is evaporated to form a suspension containing a precipitate of formula Al(OH)xAcy, where Ac is a carboxylic acid residue, x=0.1-1.5, y=2.9-1.5. The obtained suspension is neutralised with basic agents to form a suspension containing an aqueous solution of alkali and alkali-earth metal salts of carboxylic acids and a precipitate of formula Al(OH)xAcy, where Ac is an anionic carboxylic acid residue, x=0.1-3.0, y=2.9-0.0. The precipitate is separated from the aqueous solution. The precipitate obtained in the first, second and third versions undergoes thermal treatment to obtain aluminium hydroxide and a free carboxylic acid and/or its anhydride and/or a mixture of carboxylic acids and/or their anhydrides, which are returned to the step for dissolving aluminosilicate material, and the obtained aluminium hydroxide is calcined to obtain alumina. ^ EFFECT: invention reduces corrosion aggressiveness of medium, minimises consumption of carboxylic acid owing to its recuperation. ^ 17 cl, 8 ex |
