METHOD FOR LIQUID-PHASE OXIDATION OF AQUEOUS SODIUM HYDROSULPHITE SOLUTION WITH ATMOSPHERIC OXYGEN Russian patent published in 2011 - IPC C01D5/04 

FIELD: chemistry.

SUBSTANCE: process for liquid-phase oxidation of aqueous sodium hydrosulphite solution with atmospheric oxygen is carried out in a vertical-type bead mill fitted with an air bubbler, with weight ratio of the load to the glass beads equal to 1:1. Flow rate of air must be 0.4-1.2 l/(min-kg of load). Sodium hydrosulphite is added in form of 2.0-2.5 mol/l of aqueous solution with equimolar content sodium chloride. The reaction mixture undergoes fractional selection while keeping its volume constant. The maximum possible concentration of sodium hydrosulphite in the reaction mixture is 0.03-0.10 mol/l. The catalyst used is manganese (II) sulphate and its concentration is kept at 0.01-0.06 mol/l through periodic compensations. The process continues until the time for input of the next two portions of reagent increases 5-7 times compared to the minimum value after the second and next inputs. After that, the reaction mixture is separated from the glass beads.

EFFECT: more complete and faster oxidation of sodium hydrosulphite and simplification of the process.

3 cl, 1 tbl, 14 ex