ESTIMATION OF CHROMIUM IN ORES AND BENEFICIATED PRODUCTS - AN ULTRASONIC APPROACH

Cr(III) slowly forms a violet complex with EDTA at pH 3.5 +/- 0.2 unde r normal conditions. The complex formation can be catalyzed by irradia ting the reacting mixture with ultrasonic waves. Quantitative formatio n of the complex was possible with ultrasonic waves of 15 W/cm(2) inte nsity within 7.5 min of sonication. This method may be successfully ap plied to the determination of chromium in ores and beneficiated produc ts containing 20-60% Cr2O3 without separating the analyte from the mat rix elements.