Abstract:In order to solve the problems of low recovery efficiency and high consumption of electric energy, gold was electrodeposited from the iodine leaching solution by electrodeposition. The effects of catholyte gold concentration, anolyte iodine mass fraction, anolyte n(I₂):n(I^-), and cell voltage on the gold deposition rate were investigated. Using the response surface method, the iodine mass fraction of the anode liquid, the n(I₂):n(I^-) in anode liquid, and the tank voltage were taken as variable factors, and the gold deposition rate was taken as the response value. The results show that the main effects of iodine mass fraction, anolyte n(I₂):n(I^-), and cell voltage on the gold deposition rate from greater to littler are cell voltage, anolyte n(I₂):n(I^-), anodic liquid iodine mass fraction, and a second-order regression equation with a response rate of gold deposition was obtained. The optimized process conditions are as follows catholyte gold concentration of 10 mg/L, anolyte iodine mass fraction of 0.58%, anolyte n(I₂):n(I^-) of 1:6.5, cell voltage of 12 V, electrolysis time of 2 h. The three times average gold deposition rate in the verification experiment is 97.83%, which is very close to the model prediction value of 98.15%, which proves that the quadratic polynomial model optimized by the response surface method is feasible. At the same time, the process conditions are suitable for practical application, and the gold deposition rate can still reach more than 75%.

Key words: iodinated leachate; electrodeposition method; gold deposition rate; response surface analysis; process conditions