Study on Reduction of Silver with Sodium Sulfite from Silver-containing Liquid Waste

In this paper,the influences of the pH value,the concentrations of free sulfite ions and of sodium sulfite on reduction of silver by sodium sulfite were studied based on the complex chemistry theory.The results show that the solubility of silver sulfite [Ag]T presents a non-linear functional relation with concentration of free sulfite ions [SO32-].The solubility of silver sulfite decreases with the pH value in the range of 2 and 8 and increases with the decrease of pH value at pH﹤2.The optimal pH value for the deposition of silver sulfite is 2.In the best deposition condition,the solubility of silver sulfite decreases with the concentration of sodium sulfite.At the same time,it is approved by thermodynamics analysis and calculation that silver sulfite can be reduced to silver with quite high degree.Accordingly,pH=2 is the optimal condition for the reduction of silver from solution.Finally,the correctness of the theoretic analysis is verificated by the industrial production.