三段石灰-铁盐法处理高砷污酸

摘要

A three-stage lime-ferric salt treatment process is proposed for treating high-arsenic waste acid from off-gas or pyrited-based sulphuric acid plants. In the first stage, non-dangerous solid gypsun waste is produced by neutralization with lime, which could be used as additive for cement production. In the second stage, arsenic is highly concentrated in residues by adjusting pH and/or adding oxidant to produce calcium arsenite or arsenate, which is suitable for recycle or stabilizing treatment. In the third stage, wastewater is treated by iron salt to further remove arsenic and meet industrial discharge standards. The good results were obtained in the tests treating waste acids from off-gas and pyrite-based sulphuric acid plants.%提出一种处理高砷污酸的三段石灰-铁盐法。第一段利用石灰乳中和污酸中的硫酸,得到非危险固体石膏,可作为水泥生产添加剂;第二段通过调节pH值和（或）加入氧化剂生成亚砷酸钙或砷酸钙,将砷高度富集在渣中,以便后续资源化利用或稳定化处理;第三段利用铁盐去除残留砷,使水达标排放。该法在冶炼烟气制酸和硫铁矿制酸的污酸处理试验中取得了良好的结果。