用Na2SO3与NH3分银实验研究

Experiments study on silver separated by using Na2SO3and NH3

  • 摘要: 介绍了阳极泥处理过程中, 氯化分金渣用Na2SO3分银与NH3分银的工艺过程; 研究了Na2SO3分银Na2SO3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NH3浓度、时间对分银效果的影响, 并对水合肼还原水合肼用量、时间、温度对银还原率进行了研究.结果表明, 用Na2SO3分银-甲醛还原, 当Na2SO3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4 h, 温度为30~40 ℃时, 银还原率可达96.33 %; 用NH3分银-水合肼还原, 当NH3浓度为8 %~10 %, 温度为室温, 反应时间为4 h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0.5 h时, 银还原率可达98.1 %.

     

    Abstract: Study describes the process of gold dregs that separated by Chlorine separating silver by using Na2SO3 and NH3 in the anode slime treatment process; Studied amount of silver Na2SO3, pH, time on the effects of separating silver by using Na2SO3, as well as temperature, pH effects on the rate of reduction of silver reducted by using formaldehyde; studied concentration of NH3, time on the effects of separating silver by using NH3, as well as the amount of hydrazine hydrate, time and temperature on the rate of reduction of silver by using hydrazine hydrate. The results show that separating silver of Na2SO3 -reducted by using formaldehyde, when the amount of Na2SO3is 1.3 times of the theoretical amount, pH is 9.2, and the leaching time is 4h, the silver recovery rate can be up to 97.39%, while the amount of formaldehyde (formaldehyde: Ag=1:2.5), pH is 10.5, the temperature is 30 ℃~40 ℃, reacted 4h, the silver reduction rate can be up to 96.33%; Separating silver of NH3 -reducted by using hydrazine hydrate, when the concentration of NH3 between 8% to 10%, and temperature is at room temperature, the reaction time is 4h, 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 ℃, restored 0.5h, silver reduction rate can be up to 98.1%.

     

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