METHOD FOR MANUFACTURING FREE HYDROXYLAMINE AQUEOUS SOLUTION AT HIGH YIELD

摘要

PROBLEM TO BE SOLVED: To provide a method to manufacture, at a high yield by distillation, a high purity and high concentration free hydroxylamine aqueous solution which does not substantially contain salt nor organic matters. SOLUTION: This method to manufacture a free hydroxylamine aqueous solution at a high yield rate comprises obtaining a reaction solution containing free hydroxylamine and dissolved or partly precipitated sulfate by a mixing reaction of a solution or slurry containing hydroxylammonium sulfate with alkali, then separating and removing solid sulfate precipitated in the reaction solution, thereafter controlling the concentration of the obtained sulfate in the aqueous solution to not more than 1 wt.% and distilling a free hydroxylamine aqueous solution by simple distillation at a temperature of 66 to 79 deg.C in the presence of a stabilizer of hydroxylamine.