Process for preparing crystalline hydroxyl ammonium sulfate with low ammonium sulfate content

摘要

The crystalline hydroxylammonium sulphate having a low ammonium sulphate content is prepared by bringing an aqueous solution containing 0.02 to 0.3 part by weight of ammonium sulphate and 0.02 to 0.2 part by weight of sulphuric acid per part by weight of hydroxylammonium sulphate into contact with basic ion exchangers to give a solution having a pH of 3.0 to 4.0, concentration of the aqueous hydroxylammonium sulphate solution thus obtained and crystallisation of at most 70 % by weight of the hydroxylammonium sulphate contained in the aqueous solution.