基于Box-Behnken设计优化白银炉电收尘脱砷工艺

采用低温碱性焙烧-热水浸出工艺脱除白银炉电收尘(EPD)中的砷, 主要考察了焙烧过程中碱料比、焙烧温度、焙烧时间对砷浸出率的影响, 并利用响应曲面法的Box-Behnken设计优化工艺参数。结果表明, 3个因素对EPD中砷的浸出率均有影响, 其中焙烧温度对砷浸出率影响最大。结合单因素实验结果及Box-Behnken设计优化后焙烧条件为: 碱料比1.2, 焙烧温度600 ℃, 焙烧时间2 h。优化条件下, EPD中砷浸出率为90.76%, 铅、锌、铜、铋均不浸出。低温碱性焙烧-热水浸出工艺能实现EPD中砷的选择性脱除, 有价金属富集在浸出渣中得以综合回收。

Optimization of Arsenic Removal for Electrostatic Precipitator Dust from Baiyin Furnace Based on Box-Behnken Design

A process consisting of low-temperature alkaline roasting and hot water leaching was used to remove arsenic in electrostatic precipitator dust (EPD) from Baiyin furnace. Effects of alkali-to-material ratio, roasting temperature and roasting time on the arsenic leaching rate were investigated, and the process parameters were optimized based on the Box-Behnken design with response surface method. The results show that three factors all can bring effects on the leaching rate of arsenic in EPD, and the roasting temperature has the greatest effect on the arsenic leaching rate. Based on the single-factor experimental results and the Box-Behnken design, the roasting conditions are optimized as follows: alkali-to-material ratio of 1.2, roasting temperature at 600 ℃ and roasting time of 2 h. Under the optimal conditions, the leaching rate of arsenic from EPD is 90.76%, and lead, zinc, copper and bismuth are almost not leached. It is shown that the low-temperature alkaline roasting-hot water leaching process can realize the selective removal of arsenic from EPD, and the valuable metals concentrated in the leaching slag can be comprehensive recovered.