从含重金属废水中回收铅、汞的研究

在研究单一体系中铅/汞回收的基础上, 采用分步硫化沉淀浮选法对含Pb²⁺、Hg²⁺混合废水中铅/汞的分离回收进行了研究。试验结果表明: 向混合废水中加入Hg²⁺1.1倍当量Na₂S, 反应12 min, 加入丁黄药45 mg/L, 浮选5 min, 浮选后的废水再加入Pb²⁺1.5倍当量Na₂S, 反应12 min, 加入丁黄药25 mg/L, 浮选5 min, 铅和汞回收率均达99.90%以上。经该方法处理后的废水中残余重金属含量均低于GB8979-1996一级标准。浮渣中汞品位为32.42%, 铅品位为83.25%, 具有极高的资源回收价值。

Recovery of Lead and Mercury from Wastewater Containing Heavy Metals

After an investigation on recovering lead and mercury from the single contamination system, fractional sulfide precipitation-flotation technique was adopted to separate lead from mercury in the mixed wastewater containing both Pb²⁺ and Hg²⁺. The experiment included first precipitation for 12 minutes after adding Na2S with the dosage equivalent of 1.1 times the concentration of Hg2+, plus flotation for 5 minutes with 45 mg/L butyl xanthate as the collector. The flotation wastewater was then floated for 5 minutes with 25 mg/L butyl xanthate after adding Na₂S with a dosage 1.5 times the concentration of Pb²⁺ and further precipitated for 12 minutes. Results showed the recoveries of both lead and mercury exceed 99.90%. After the treatment, the contents of residual heavy metal ions are all lower than the primary standard of GB8979-1996. The flotation concentrate containing 32.42% of mercury and 83.25% of lead, is of high recycling value.