PROCESS OF PRODUCTION OF ARSENIC ACID BY ELECTROCHEMICAL OXIDATION OF AQUEOUS SUSPENSION OF ARSENIC OXIDE (III) Russian patent published in 2003 - IPC

FIELD: synthesis of inorganic substances, production of arsenate, arsenic-organic compounds. SUBSTANCE: arsenic acid is produced by way of electrolysis of aqueous suspension of arsenic oxide (III). Aqueous suspension of 50-250 g/l of arsenic oxide (III) is utilized in the capacity of anolyte, ions of halogen in the form of hydrogen chloride or hydrogen bromide with concentration 0.5-3.0 mole/l are added to it. Solution of same halogen halide is used as catholyte. Titanium coated with mixed oxides of ruthenium and titanium, platinum or graphite works as anode. Cathode is any current-conducting material resistant to action of solutions of halogen halide acid. Electrolysis is conducted in electrolyzer with cation-exchange membrane with anode density of current from 0.1 to 3.0 kA/sq.m, at temperature between 10-50 C with subsequent driving-off of halogen halide. Titanium, wolfram or graphite is employed in the capacity of cathode resistant to attack of solutions of hydrochloric and hydrobromic acids. EFFECT: production of pure arsenic acid with maximum possible output with current density securing realization of process on commercial scale. 1 cl, 1 dwg