Reinforced aluminum ash desalting and denitriding method

Abstract

The invention discloses a reinforced aluminum ash desalting and denitriding method. The method comprises the following steps: 1), dry-milling aluminum ash below 100 meshes and mixing the aluminum ashand water according to a certain ratio; 2), stirring and ball-milling obtained slurry at room temperature for certain time, and absorbing produced ammonia gas; 3), filtering fine slurry to obtain filter cakes and filtrate, and recycling industrial salt by evaporating the filtrate; 4), mixing the filter cakes and alkaline liquid, carrying out thermal preservation, stirring and hydrolysis, and absorbing produced ammonia gas to obtain ammonia water or ammonium salt; 5), filtering the slurry subjected to thermal preservation and hydrolysis to obtain residues and filtrate, and using washed and dried residues as secondary aluminum concentrates; and 6), adding a reactant into the filtrate to remove aluminum and obtain precipitates, and returning the alkaline liquid to a stirring, thermal preservation and ammonia removing section. By carrying out a hydrolysis procedure through the two sections of room-temperature stirring and ball-milling and high-temperature alkaline adding, the hydrolysis rate is high, and hydrolysis is thorough; and at the same time, the recycling of nitrogen and aluminum in aluminum nitride is realized, and a novel path is provided for the harmless recycling of the aluminum nitride in the aluminum ash.

Description

technical field [0001] The invention relates to the technical field of harmless treatment of electrolytic aluminum solid waste, in particular to a method for strengthening aluminum ash desalination and denitrification. Background technique [0002] Aluminum ash is the solid waste produced in the process of electrolytic aluminum and aluminum smelting, the main components are metal aluminum, alumina, aluminum nitride, fluoride salt, chloride salt, etc. Most of the aluminum ash treatment methods at home and abroad are extensively extracting the metal aluminum contained in it, and the remaining aluminum ash is piled up or landfilled in large quantities, causing environmental pollution. The content of aluminum nitride in aluminum ash is generally 10-30%, and it is relatively active. When it meets water, it is prone to hydrolysis reaction to generate ammonia gas, which is harmful to people and the environment. However, since the aluminum hydroxide and aluminum oxyhydroxide produc...

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Problems solved by technology

[0003] At present, some patents have announced the removal method of aluminum nitride in aluminum ash. Patent CN 108217688A has announced a deep hydrolysis method of aluminum nitride in aluminum ash. The newly formed aluminum hydroxide on the surface of aluminum nitride, but due to the limited solubility of ammonia in aqueous solution and the mild hydrolysis conditions, aluminum nitride cannot be completely removed; patent CN 108671462 A discloses a method for removing nitrogen from aluminum ash slag. It is to add reactants during the reaction process of aluminum ash and hydrolysis, so as to promote the combination of ammonia and reactants to form ammonium salts, which are dissolved in the solution, but the cost of reagents in this method is relatively high

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