METHOD OF PRODUCING AMMONIUM SULPHATE Russian patent published in 2013 - IPC C01C1/24 C01C1/245 

FIELD: chemistry.

SUBSTANCE: invention relates to production of ammonium sulphate which can be used as nitrogen fertiliser in agriculture. The method involves neutralising a solution containing iron sulphate and sulphuric acid, separating the obtained iron hydroxide precipitate to obtain ammonium sulphate solution, evaporating the ammonium sulphate solution, crystallising and drying the crystals to obtain the end product. The solution which contains iron sulphate and sulphuric acid used is waste dump and quarry water from abandoned iron-copper-zinc sulphide ore deposits containing 1-40 g/l iron (III) sulphate and 2-10 g/l sulphuric acid. Neutralisation is carried out with carbamide, taken in molar ratio of the sulphate ion to carbamide of 1:1.0-1.1, and the neutralisation process is carried out at temperature of 95-99°C until achieving pH of the reaction mixture of 6-7.

EFFECT: efficient use of waste water components.

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