CHROMIUM(VI) NEUTRALIZATION AMPEROMETRIC CONTROL METHOD Russian patent published in 2000 - IPC

FIELD: electrodeposition and analytical methods. SUBSTANCE: chromium(VI) neutralization in the course of electroplating waste water treatment is controlled by measuring value and direction of current flowing through measuring electrode operated under voltage from +450 to +930 mV relative to reference electrode. Measurements are carried out at concentration of acid in medium being controlled (K, g-equ/l) satisfying condition: K ≥ A + B*X at chromium(VI) concentration from 0 to 100 mg/l, where A is coefficient equal to 0.14 g-equ/l for aqueous solutions, B coefficient equal to 0.004 g-equ/l, and X concentration of chromium(VI) in medium, mg/l. K ≥ 0.55 g-equ/l when concentration of chromium(VI) exceeds 100 mg/l. Reference electrode is made of either copper or its alloys containing at least 60% copper. EFFECT: optimized control due to elimination of false signal, increased accuracy and sensitivity. 2 cl, 2 tbl