METHOD OF PRODUCING CRYSTALLINE HYDROXYLAMINE SULPHATE Russian patent published in 2019 - IPC C01B21/14 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, specifically to production of crystalline hydroxylamine sulphate (HAS), which is used in production of chemical reagents and materials: varnishes, photoreagents, film photographic materials, for production of hydroxylamine free base for radioelectronic industry needs. Disclosed is a method of producing crystalline hydroxylamine sulphate from an aqueous solution of hydroxylamine sulphate, involving evaporation of an aqueous solution of hydroxylamine sulphate at high temperature in a vacuum, crystallisation of the evaporated solution while stirring to obtain a mixture of a low-concentration hydroxylamine sulphate solution and hydroxylamine sulphate crystals, centrifuging, drying with hot air and obtaining several low-concentration hydroxylamine sulphate solutions, combining and directing the combined stream to a step for preparing an aqueous hydroxylamine sulphate solution, in which evaporation is carried out at temperature of 60–75 °C and residual pressure of 250–300 mm Hg, crystallisation is carried out at temperature of 16–25 °C, and the mixture obtained after crystallisation of the low-concentration solution of hydroxylamine sulphate and hydroxylamine sulphate crystals is directed to the decantation stage to obtain wet crystals of hydroxylamine sulphate and a low-concentration hydroxylamine sulphate solution.

EFFECT: reduction of power inputs and simplification of process technology.

1 cl, 2 dwg, 1 tbl