Recovery of Precious Metals from the Solution after DETA Rhodium Precipitation by Two-step Reduction Method
Address to the difficulty of replacing precious metals in the solution after DETA rhodium precipitation,a two-step reduction and recovery process was proposed.First,divalent tin salt was added to reduce and activate the precious metals in the solution,and then replacement metals were added for secondary reduction and replacement.The effects of acidity,temperature,time,and addition of activation metal and replacement metal on the final recovery rate of precious metal replacement were studied.The results show that under the conditions of pH≤2,temperature of 80-90℃,activation time of 60-120 minutes,mass ratio of SnCl2·2H2O to precious metal m(Sn)/m=10,replacement temperature of 80-100℃,and mass ratio of zinc powder to precious metal m(Zn)/m=50,the total displacement recovery rate of platinum,palladium,and rhodium is>99.5%,and the total content of platinum,palladium,and rhodium is>95%.
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