用Na_2SO_3与NH_3分银实验研究

Silver separation by using Na_2SO_3 and NH_3

介绍了阳极泥处理过程中，氯化分金渣用Na2S03分银与NH3分银的工艺过程；研究了Na2S03分银Na2S03用量、pH、时间对分银效果的影响，以及甲醛还原温度、pH对银还原率的影响，以及NH3分银NH，浓度、时间对分银效果的影响，并对水合肼还原时水合肼用量、时间、温度对银还原率进行了研究．结果表明，用Na2S03分银-甲醛还原，当Na2S03的用量为理论量1．3倍，pH值为9．2，浸出时间4h时，银浸出率可达97.39％，当甲醛用量为（甲醛：银=1：2．5），pH值为10．5，反应4h，温度为30-40℃时，银还原率可达96．33％；用NH，分银-水合肼还原，当NH3浓度为8％-10％，温度为室温，反应时间为4h时，银浸出率可达96．23％，当水合肼用量为理论量2倍，温度60℃，还原0．5h时，银还原率可达98．1％．

This paper studies the silver the anode slime treatment process. The separation by using Na2S03 and NH3 effects of Na2SO3 amount, pH, time on out of gold dregs chlorination in the silver separation effects, and the effects of formaldehyde reduction temperature, pH on the reduction rate are researched. We also investigates the effects of NH3 concentration, time on silver separation results and the effects of hydrazine hydrate amount, time and temperature on silver reduction rate. The results show that separating silver of Na2SO3-reduced by using formaldehyde, when the amount of Na2S03 is 1.3 times of the theoretical amount, pH is 9.2, and the leaching time is 4 h, the silver recovery rate can be up to 97.39 %, while the amount of formaldehyde （formaldehyde ：Ag=l ：2.5 ）, pH is 10.5, the temperature is 30-40 ~C, reacted 4 h, the silver reduction rate can be up to 96.33 %; Separating silver of NH3-reduced by using hydrazine hydrate, when the concentration of NH3 between 8 % to 10 %,and temperature is at room temperature, the reaction time is 4 h, the silver leaching rate can be up to 96.23 %, when the amount of hydrazine hydrate is 2 times of the theoretical amount, temperature is 60 ~C, restored 0.5 h, silver reduction rate can be up to 98.1%