基于沉淀法的化学镀镍废水处理工艺

Process for treatment of the wastewater discharged from electroless nickel plating production based on chelating precipitation

在pH为4～6的条件下,以二甲基二硫代氨基甲酸钠或二乙基二硫代氨基甲酸钠作为螯合剂与化学镀镍废水中的镍离子反应生成沉淀,过滤分离沉淀物。然后调节并保持废水的p H为11～12,加双氧水氧化次磷酸根、剩余的螯合剂以及其他有机物(如柠檬酸和乳酸),再加氯化钙沉淀由次磷酸根氧化生成的磷酸根。镍的出水浓度可满足GB 21900–2008《电镀污染物排放标准》中"表3"的要求。

The nickel ions in electroless nickel plating wastewater were removed by precipitation with chelating agent such as sodium dimethyldithiocarbamate and sodium diethyldithiocarbamate at pH4-6,and the precipitates were filtered out.The filtrate was adjusted to pH11-12,and then the sodium hypophosphite,residual chelating agent,and other organic substances(such as citric acid and lactic acid)in it were oxidized by adding H2O2.The phosphate produced by the oxidation of hypophosphite was precipitated by calcium chloride.The effluent Ni concentration met the requirement of the Table3stipulated by the Emission Standard of Pollutants for Electroplating(GB21900–2008).