Method for treating alkaline zinc-nickel alloy electroplating waste water

Abstract

The invention discloses a method for treating an alkaline zinc-nickel alloy electroplating waste water. The method comprises the following steps: adjusting the pH of the alkaline zinc-nickel alloy electroplating waste water to be 3-4, adding an aqueous solution of sodium diethyldithiocarbamate for precipitating zinc and nickel, and adding a flocculating agent to make precipitation particles aggregated; adjusting the pH of the electroplating waste water to be 4.5-5.5, and adding a sodium hypochlorite solution; and adjusting the pH of the treated electroplating waste water to be 6-9 to obtain required matter. The treatment method for the alkaline zinc-nickel alloy electroplating waste water provided by the invention can completely precipitate zinc and nickel ions with the sodium diethyldithiocarbamate through controlling the pH of the waste water in a sedimentation tank to be 4.5-5.5; and hydrogen peroxide does not need to be added to destroy aliphatic polyamine strong complexing agentsin the waste water, so that the treatment process is simplified, and the treatment process can interface with current electroplating waste water treatment equipment, solves the difficulty in the treatment of the alkaline zinc-nickel alloy electroplating waste water, and has better market application prospects.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for treating alkaline zinc-nickel alloy electroplating wastewater, especially a method for precipitating zinc and nickel ions in alkaline zinc-nickel alloy electroplating wastewater. Background technique [0002] Zinc-nickel alloy coatings have excellent corrosion resistance and have been widely used as protective coatings for automobiles and other accessories. Alkaline zinc-nickel alloy plating solution contains about 3% aliphatic polyamine complexing agent. This complexing agent has high stability. Oxidation with hydrogen peroxide or bleaching water at room temperature cannot effectively destroy these complexing agents. Therefore, in the popularization and use of the alkaline zinc-nickel alloy electroplating process, it has been facing the difficulty of electroplating wastewater treatment. [0003] The Chinese invention patent "A Treatment Met...

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Problems solved by technology

This method takes 10 hours to oxidize with hydrogen peroxide and requires relatively large reaction equipment. At present, small and medium-sized electroplating enterprises cannot connect with the existing wastewater treatment equipment when implementing this scheme, and the reconstruction of wastewater treatment equipment is restricted by the site.

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