FIELD: industrial inorganic synthesis. SUBSTANCE: invention relates to processing of hydromineral raw materials, in particular to processing of iodine- containing waters, and aims to reduce process cycle and to increase desired product yield. Elementary iodine is made react with potassium hydroxide to form potassium iodate and potassium iodide both dissolved in reaction milieu having alkalinity up to 8 g/l and containing up to 160 g/l iodide anions and up to 50 g/l iodine cations. Reaction milieu is subjected to electrolysis and then concentrated at temperature no lower than 80 C, after which follows crystallization caused by cooling of reaction milieu to ambient temperature and isolation of desired product crystals. Optionally, electrolysis of reaction milieu can be accompanied by potassium iodide oxidation. EFFECT: reduced process time. 4 cl, 2 ex
