Abstract:A two-step reduction and recovery process is proposed to address the difficulty of replacing precious metals in the solution after DETA rhodium precipitation. First, add divalent tin salts to reduce and activate the precious metals in the solution, and then add replacement metals for secondary reduction and replacement. The effects of acidity, temperature, time, activation metal and replacement metal addition on the final recovery rate of precious metal replacement were studied. The results show that under the conditions of pH value ≤2, temperature 80-90℃, activation time 60-120 minutes, SnCl₂ ? 2H₂O to precious metal mass ratio of 10:1, replacement temperature 80-100℃, and zinc powder to precious metal mass ratio of 20:1, The total displacement recovery rate of platinum, palladium, and rhodium is greater than 99.5%, and the total content of platinum, palladium, and rhodium is greater than 95%.