响应曲面法优化硫脲浸出烧结灰中银的工艺研究

以炼铁烧结机头除尘灰(烧结灰)为实验原料,通过XRF、XRD、SEM-EDS手段对原料进行表征,采用酸性硫脲法浸出烧结灰提取银。在单因素实验的基础上,使用响应曲面法(RSM)对烧结灰中提取银的工艺条件进行优化,以炼铁烧结灰中银的浸出率为响应值,选取对硫脲浸出烧结灰提银过程有显著影响的变量(反应温度、硫脲浓度、浸出时间)作为考察因素,采用Central Composite Design(CCD)中心设计方案以三因素五水平设计实验,得到最优的提银工艺条件,并获得拟合度高的二阶多项式模型。结果表明:硫脲浸出烧结灰中银的最佳工艺为反应温度50℃、硫脲浓度22g/L、浸出时间90min;在最佳提取条件下,银浸出率的模型预测值为89.38%,实验真实银的浸出率为89.9%,其相对误差为0.52%,表明实际值与模型预测值接近,可用于预测烧结灰提取银的浸出过程。

Optimization of Thiourea-assisted Silver Leaching from Sintering Dust by Response Surface Methodology

The dust of iron-making sintering process arrested by electrostatic precipitation (sintering dust)that were used as the experimental materials,and the chemical compositions and phases of sintering dust were characterized by XRF,XRD,SEM-EDS techniques,acidic thiourea were applied for silver extraction from sintering dust.The re-sponse surface methodology (RSM)was used to optimize the extraction conditions on the basis of single factor experi-ments in silver leaching process.Silver leaching rate as response indicators,and the process variables (reaction tem-perature,thiourea concentration,leaching time)as independent factors were investigated with significant effect on sil-ver leaching from sintering dust,then central composite design (CCD)involving three factors at five levels was em-ployed in silver extraction from sintering dust.Optimal process parameters on silver extraction from sintering dust and two order polynomial equation of model with high fitting degree were obtained.The results show that optimum tech-nological conditions are that reaction temperature at 50 ℃,thiourea concentration at 22 g/L and the leaching time at 90 min.Under the optimum conditions,the theoretical leaching rate of silver of model predicts can reach 89.38%, while the experimental value is 89.9% with a relative stand error is 0.52%.It indicated that the actual value is close to the model prediction value,thus the model can be used to predict the leaching silver from the sintering dust.