Optimization of silver leaching using ultrasonic technology from sintering dust by response surface methodology

The water washed sintering dust was used as raw materials. Acidic thiourea was applied for silver extraction with ultrasonic-augment technology in the leaching process. The effects of ultrasonic power, particle size, leaching time, thiourea concentration and reaction temperature on the leaching rate of silver were explored. On the basis of experiments, the response surface methodology (RSM) was used to optimize the extraction process to obtain the optimal process parameters and two order polynomial equation of fitting model. The results showed that optimum conditions at particle size with 75~96 μm, the leaching time at 90 min, thiourea concentration of 22 g/L and reaction temperature of 50℃, the model predictive value of silver can reach to 96.15%, while the experimental value is 95.7%, with a relative error 0.45% to theoretical value. It is indicated that the model can be used to predict silver extraction process from water washed sintering dust.