Study On Process Of Electroplating Wastewater With Cyanide

As being the main heavy metal pollutant source, electroplating wastewater includes: CN^-, Cr(â…¥), Cu²⁺, Ni²⁺ and the organic pollutant.CN^-,Cr(â…¥), Cu²⁺, Ni²⁺ et al heavy metal ions have extremely high toxicity, if it discharged without treatment, will pollute the water seriously, so we must control its discharging density strictly. Usually, the electroplating wastewater mixes CN^-, the general methods are not suitable. The process in my paper, Fenton—micro electrolysis technology can process this kind of electroplating wastewater with cyanide effectively.The Fenton reagent is one kind of strong oxidant which can be used to remove CN^- and COD in electroplating wastewater with cyanide. In my paper, micro electrolysis technology uses the national monopoly of Duo—Yuan—Mei compound processing purification technology . It may remove the heavy metal ions in the wastewater effectively.In my paper, firstly I take the Yuanquan electroplating factory's wastewater as the research object, Huizhou city, Guangdong Province. We use the process of Fenton reagent and Duo—Yuan—Mei compound processing purification technology. In the experimental, I controlled pH in synthesis pond to be 2-3, used the Fenton reagent to oxide comprehensive wastewater, in order to remove its CN^- and COD; the current went to Duo—Yuan—Mei compound processing purification tower which can turn Cr(â…¥) to Cr³⁺; with the aid of Na₂S, the process may transform complex cupric ion to Cu²⁺; by controlling pH in sedimentation pond, Cr³⁺, Cu²⁺, and the Ni²⁺ can be settled completely.In the later period, I utilized this process in Jianhong electroplating factory to treat its electroplating wastewater with cyanide. Through the experiment, I knew the best process condition in Jianhong electroplating factory.With the aid of optimized experiment in the two electroplating factories, I knew the Fenton reagent's best working condition to process this kind of electroplating wastewater; studied the removing effect of Cr(VI) by Duo—Yuan—Mei compound processing purification; studied the removing effect of complex cupric ion by Na₂S; determined the best precipitation condition of Cr³⁺, Cu²⁺, Ni²⁺ in my treating process.The findings indicated that, if the entering water pH is 2-3, the Fenton reagent may effectively remove the CN^- and COD in electroplating wastewater, CN^- removing rate may achieve 84.35%, COD removing rate may achieve 81.20%; with the aid of Duo—Yuan—Mei compound processing purification tower , Cr(VI) removing rate may achieve 94.38% , Cu²⁺ removing rate may achieve 93.26% , controlling the pH =10 - 11 of entering wastewater, may precipitate the Cr³⁺, Cu²⁺, Ni²⁺ in the leakage from Duo—Yuan—Mei compound processing purification tower completely, enables the two factory's electroplating wastewater quality achieves the Standard of Guangdong Province water pollution discharges (DB44/26—2001) first standard in second level.