Study on hydrogen peroxide synergistic nitric acid leaching of silver in a failed silver catalyst.

The effect of hydrogen peroxide leaching of silver was studied on the basis of traditional nitric acid leaching of silver from spent silver catalysts. The silver leaching rate was 99.76% by slowly adding hydrogen peroxide in the conditions of 2 mol/L HNO₃, leaching temperature 70 °C, leaching time 120 minutes, and solid-liquid ratio 1:4, which had good leaching effect. Hydrogen peroxide oxidizes Ag to Ag₂O, which can effectively improve the leaching rate of silver, while the nitrogen oxide produced by the reaction between nitric acid and silver is oxidized by H₂O₂ to generate nitric acid and continue to participate the reaction. The use of nitric acid hydrogen peroxide as a leaching agent ensures efficient silver leaching, reduces the emission of nitrogen oxides, and provides a theoretical basis and technical support for the green and efficient recovery of spent silver catalysts. [ABSTRACT FROM AUTHOR]