METHOD OF PURIFYING ACIDIC SALT SOLUTIONS CONTAINING ALUMINIUM NITRATE FROM IRON Russian patent published in 2013 - IPC C01F7/24 C01F7/66 C02F1/64 

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry and can be used in processing alumina-containing material using acid-based techniques. Acidic salt solutions containing aluminium nitrate are mixed with a base until neutralisation of free nitric acid and hydrolysis of iron nitrate to iron hydroxide. The obtained solution is held for 30-90 minutes at temperature of 90-160°C. Once the obtained pulp reaches pH 1.5-2.3, it is removed from the reactor, cooled and mixed with a cationic polyelectrolyte. The iron-containing precipitate is thickened and separated from the purified salt solution. Control of the salt solution and base ratio and adjustment of the pH of the pulp are carried out by further addition of the salt solution or base directly into the pulp. The thickened iron-containing precipitate is separated from the salt solution by settling. The bases used are sodium or potassium hydroxides, or aqueous ammonia solution or aluminium hydroxide or aluminium oxide monohydrate - boehmite, AlOH. In the temperature range of 90-109°C, the reactor equipment operates at atmospheric pressure and at high pressure in the temperature range of 110-160°C.

EFFECT: invention enables to extract 75-95% iron from acidic salt solutions and remove iron from the process cycle.

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