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利用硫氰酸铵做浸出剂,对除砷、提铜后二次污泥中的银做了浸出试验研究,探讨了浸出剂浓度、反应时间及温度、氧化剂用量及固液比等影因素响,确定了最佳浸银工艺路线及工艺参数.正交试验、单因素优化试验及放大试验表明:硫氰酸铵为95 kg/t、MnO2为6.8 kg/t、浸出温度25℃、液固比为2.5∶1、pH为2时,两次浸银的总浸出率可达95%.对提银反应动力学机理进行了研究,硫氰酸铵浸出反应级数为0.5,活化能为12.574 kJ.mol-1,反应速率常数为:k=1.883 e-12574/RT.
Using ammonium thiocyanate as a leaching agent, the leaching experiments of silver in the secondary sludge after arsenic removal and copper extraction were studied. Factors such as concentration of leaching agent, reaction time and temperature, dosage of oxidant and solid-liquid ratio , The best route and technological parameters of silver immersion were determined.The orthogonal test, single factor optimization test and enlargement test showed that ammonium thiocyanate was 95 kg / t, MnO2 was 6.8 kg / t, leaching temperature was 25 ℃, Ratio of 2.5: 1, the total leaching rate of twice immersion silver reaches 95% at pH 2. The kinetic mechanism of silver extraction reaction is studied, the reaction conditions of ammonium thiocyanate leaching reaction is 0.5 and the activation energy is 12.574 kJ.mol-1, the reaction rate constant: k = 1.883 e-12574 / RT.