碱性锌镍合金电镀和钝化废水的组合处理工艺  

Combined process for treating alkaline zinc-nickel alloy electroplating and passivation wastewater

作　　者：郭崇武[1] 赖奂汶[1] 夏亮 GUO Chongwu;LAI Huanwen;XIA Liang(Guangzhou Ultra Union Chemicals Ltd.,Guangzhou 510460,China)

机构地区：[1]广州超邦化工有限公司,广东广州510460

出　　处：《电镀与涂饰》2021年第7期579-583,共5页Electroplating & Finishing

摘　　要：向碱性锌镍合金电镀与钝化混合废水中加稀盐酸,调节其pH至4~6后加入氯化亚铁,再用石灰乳液调节pH至10~12,利用亚铁离子和钙离子的协同作用来沉淀羧酸配位剂,三价铬离子生成氢氧化物沉淀。过滤分离沉淀物后以稀盐酸调节上清液的pH至4.5~5.5,加二甲基二硫代氨基甲酸钠沉淀镍、锌、钴等离子。再次过滤分离沉淀物后以氢氧化钠溶液调节废水的pH至6~8,用生化降解法降低其化学需氧量。该工艺成本低,处理结果至少可满足GB 21900-2008《电镀污染物排放标准》的“表2”要求。Ferrous chloride was added to the wastewater discharged from Zn-Ni alloy electroplating and subsequent passivation after its pH was adjusted with diluted hydrochloric acid to the range from 4 to 6.Carboxylic acid complexants in the wastewater were precipitated after adjusting its pH to 10-12 with lime emulsion by the synergistic effect of ferrous ion and calcium ion,and trivalent chromium ions were precipitated as hydroxides.The supernatant produced by sedimentation was added with diluted hydrochloric acid to adjust its pH to 4.5-5.5,and then added with dimethyldithiocarbamate to precipitate the nickel,zinc,and cobalt ions in it.The precipitates produced were filtered and separated out,and the wastewater was further treated by biodegradation to reduce its chemical oxygen demand after adjusting its pH to 6-8 with sodium hydroxide solution.The process is cost-efficient and at least compliant with the“Table 2”in the Emission Standard of Pollutants for Electroplating(GB 21900-2008).

关 键 词：电镀碱性锌镍合金 钝化 废水处理 羧酸配位剂 螯合 沉淀 

分 类 号：TQ153.2[化学工程—电化学工业] X781.1[环境科学与工程—环境工程]