METHOD FOR PRODUCING HYDROXYLAMINE SULPHATE CRYSTALS Russian patent published in 2022 - IPC B01D9/02 C01B21/14 C30B7/08 C30B29/10 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology for producing crystals of hydroxylamine sulphate (HAS), used in production of caprolactam and chemical reagents. The method for producing crystals of hydroxylamine sulphate (HAS) from an aqueous HAS solution includes producing a process HAS solution 1, evaporation 2, 3 thereof at an elevated temperature in a vacuum, crystallisation 11 of the evaporated solution while stirring, resulting in a mixture of the HAS solution and HAS crystals, centrifugation 15, drying 19 with hot air and producing several HAS mother solutions 17, 22, wherein the evaporation 2, 3 is executed at a residual pressure of 300±10 mm Hg, the process of evaporation of the process HAS solution begins at 80°C and is completed at 85°C, and the end of the evaporation process is determined by obtaining a condensate 6 in the neutraliser 8 in a volume of 35 to 40% of the initial volume of the process HAS solution, crystallisation 11 is executed while stirring and at a temperature of 9±2°C for 12 h, and the mixture 14 of the HAS solution and HAS crystals obtained after crystallisation is directed to the stage of centrifugation 15, resulting in a primary HAS mother solution 17 and HAS crystals 16, wherein the primary HAS mother solution 17 from processing at least two portions of the processing HAS solution is combined and evaporation 2, 3 of the combined primary HAS mother solution is executed, starting at a temperature of 85±3°C, completed at a temperature of 90±3°C, and the evaporation is finished when a condensate 6 is obtained in the neutraliser 8 in an amount of 10 to 15% from the initial volume of the primary HAS mother solution 17, wherein the crystallisation 11 is executed while stirring and at a temperature of 9±2°C for 12 h, and the mixture 14 of the HAS solution and HAS crystals obtained after crystallisation is directed to the stage of centrifugation 15, resulting in an additional amount of HAS crystals 21 and a secondary HAS mother solution 22, returned to the stage of producing a process HAS solution 1, wherein a solution of ammonium sulphate 9 for disposal at biological treatment plants is produced from the condensate 6.

EFFECT: increase in the total yield of crystalline commercial HAS to 89%.

1 cl, 1 dwg