| Sintering dust (SD) was produced in flue gas and dust trapping from the sintering process of iron and steel smelting, China’s steel output ranked first in the world, so the yield of SD produced during sintering process was very large annually. The treatment of SD was not reasonable will cause great harm for the environment and production. which contains a large number of elements such as potassium, iron, carbon, lead, silver with high comprehensive recovery value. At present, the extraction of silver was rarely reported. If the precious metal silver was recovery, not only reduced the pressure on SD treatment, but can bring additional economic benefits for the enterprise. The SD as raw material, and thiourea solution as leaching agent with ultrasonic enhancement technology in this paper. The new process of recovering silver from SD will be explored, the main contents are as follows:(1) The effects of ultrasonic power, particle size, reaction temperature, etc were investigated on silver leaching process. Optimum leaching process conditions: ultrasonic power with 400 W, the particle size at 96～75μm, the reaction temperature is 50 ℃, thiourea concentration of 22 g/L, stirring speed with 400 r/min, the liquid-solid ratio of 8:1 under reaction time 90 min, and the leaching rate of silver can be reached 94.70%.(2) The leaching process of silver was optimized by response surface methodology on the basis of single factor experiment, and the optimal experimental conditions were obtained. Under the experimental conditions, the predicted value is 96.15%, the actual value is 94.70%, and the absolute error is 1.45%, which indicates that the process of silver extraction can be optimized by fitting model.(3) The kinetics of extraction process of silver from the WR-SD was research, and the apparent activation energy is 18.19 kJ/mol under silver leaching, and reaction rate of leaching process is controlled by the internal diffusion though solid products.
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