二甲基二硫代氨基甲酸钠处理锌冶炼含镉废水

以二甲基二硫代氨基甲酸钠(福美钠)作为脱镉螯合剂,以聚合氯化铝作为絮凝剂,脱除含镉废水中的Cd2+。在考察福美钠加入量、搅拌时间、聚合氯化铝加入量、沉淀时间等工艺条件对Cd2+脱除效果影响的单因素实验的基础上,采用正交实验对工艺参数进行进一步优化。实验结果表明:在福美钠加入量为1.0 g/L、搅拌时间为20 min、聚合氯化铝加入量为0.2 g/L、沉淀时间为5 h的最佳工艺条件下,采用福美钠处理初始Cd2+质量浓度为100 mg/L的锌冶炼含镉废水,剩余Cd2+质量浓度降至0.008 mg/L,Cd2+去除率为99.99%,处理后的废水达到GB8978—1996《污水综合排放标准》。

Treatment of Cadmium-Containing Wastewater in Zinc Smelting Using Sodium Dimethyl Dithio Carbamate

Cd²⁺ was removed fron the cadmium-containing wastewater using sodium dimethyl dithio carbamate （SDD） as chelating agent and polyaluminium chloride （PAC） as flocculant. The process parameters were further optimized by orthogonal experiments on the basis of single factor experiments for investigating the factors effecting Cd²⁺ removal,such as：SDD dosage,stirring time,PAC dosage,precipitation time,and so on. The experimental results show that：Under the optimum process conditions of SDD dosage 1.0 g/L,stirring time 20 min,PAC dosage 0.2 g/L ,precipitation time 5 h and initial Cd²⁺ mass concentration 100 mg/L,the mass concentration of residual Cd²⁺ is as low as 0.008 mg/L,the Cd²⁺ removal rate is 99.99%. The treated wastewater can meet the national discharge standard of GB 8978-1996.