用生产钛白的副产物绿矾处理含铬废水

Chromium-Containing Wastewater Treatment by Copperas Byproduct in Titanium Dioxide Production

处理含铬废水的方法较多,但效果不太理想。以生产钛白的副产物绿矾作为还原剂,通过氧化还原、中和沉淀、分离等步骤处理含铬废水,研究了绿矾处理含铬废水的工艺条件。结果表明,按铁铬比20、氧化还原反应的pH值3.5～4.0、氧化还原时间15～20min和中和反应的pH值6.5、中和反应时间10～15min的工艺条件,对含Cr6+35mg/L左右的废水进行处理,铬的去除率达到97.4%以上,处理后的水样中Cr6+含量小于0.50mg/L、总铬含量小于1.0mg/L,达到国家排放标准。

It is imperative to develop novel efficient technology for the treatment of Cr-containing wastewater, because various available methods for the treatment of Cr-containing wastewater have many limitations in practice. Thus copperas as the byproduct in the production of titanium dioxide (titanium white) was used as a reducing agent to treat Cr-containing wastewater. The process conditions were studied with respect to oxidation-reduction, neutralization-precipitation, separation, and so on. The optimum technological conditions were suggested as Fe/Cr ratio 20, pH value of oxidation-reduction reaction 3.5~4.0, oxidation-reduction time 15~20 min, pH value of neutralization reaction 6.5, and neutralization time 10~15 min. Moreover, the chromium in the wastewater containing about 35 mg/L was removed at a rate over 97.4%, and the Cr^(6+) content and total chromium were less than 0.50 mg/L and less than 1.0 mg/L, respectively, after treating using the optimized technological conditions. The treated water was qualified to the national discharge standard.