Rapid Determination of Thiourea Concentration in Copper Electrolyte

Due to the characteristics of high salt and high acidity of the electrolyte and the chemical reaction between thiourea (Tu) and metal ions, it is still a problem to quickly and accurately detect Tu concentration in copper electrolyte. An improved spectrophotometric method has been proposed by simplifying the extraction steps of the traditional extraction–spectrophotometry and reducing the dosage of extractant and buffer. The improved method, with a favorable R² of 0.9991, great precision of 1.67% and excellent spiked recovery of 102.19%, was not affected by the presence of gelatin and copper ions. Moreover, based on the spectrophotometry, a colorimetric method for rapid detection of Tu concentration in copper electrolyte was proposed. Using the standard color card produced enabled the expeditious determination of the concentration range of Tu in copper electrolyte. Since the gray value of the standard color card is linearly related to the Tu concentration, it is feasible to determine the Tu concentration by measuring the gray value of the test strip, and its accuracy was verified by spectrophotometry. The colorimetric method has satisfactory results in industrial practice. This study provides a novel approach for the rapid detection of Tu concentration in the copper electrolysis industry.