Combined treatment method of electroplating mixed wastewater

Abstract

The invention discloses a combined treatment method of electroplating mixed wastewater. The method comprises the steps of adjusting and maintaining pH of the wastewater to 10.5-12 by using lime emulsion, and adding sodium hypochlorite sodium cyanide oxide, organic amine containing hydroxyl and like pollutants; adding a ferrous chloride solution, and precipitating an organic acid coordination agentcontaining carboxyl in the wastewater by using ferrous ions and calcium ions together, wherein the ferrous ions reduce hexavalent chromium into trivalent chromium and generate chromium hydroxide precipitate; filtering to remove the precipitate; adjusting a pH value of the wastewater to 4.5-5.5, precipitating heavy metal ions by using sodium dimethyldithiocarbamate or sodium diethyldithiocarbamate, and adsorbing precipitates and a heavy metal trapping agent by using activated carbon; filtering to remove precipitate; and adjusting the pH value of the wastewater to 6-8, and destroying the aliphatic polyamine complexing agent and reducing COD by using the existing biodegradation technology. Through the method disclosed by the invention, the heavy metal and like pollutants in the electroplating mixed wastewater can be effectively removed, the treatment cost is low, and the method has good market application prospect.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, in particular to a comprehensive treatment method for electroplating mixed wastewater. Background technique [0002] Electroplating mixed wastewater generally includes: cyanide copper plating wastewater, pyrophosphate copper plating wastewater, acid copper copper plating wastewater, bright nickel plating wastewater, potassium chloride galvanizing wastewater, cyanide-free alkaline galvanizing wastewater, imitation gold cyanide copper Zinc alloy electroplating wastewater, gun black tin-nickel alloy electroplating wastewater, alkaline zinc-nickel alloy electroplating wastewater, acid zinc-nickel alloy electroplating wastewater, hexavalent chromium plating wastewater, trivalent chromium plating wastewater, chemical nickel plating wastewater, chemical copper plating wastewater, Hexavalent chromium passivation wastewater, trivalent chromium passivation wastewater, degreasing was...

AI Technical Summary

Problems solved by technology

[0003] Sodium citrate is a complexing agent commonly used in electroplating, electroless nickel plating and trivalent chromium passivation. Sodium citrate has strong oxidation resistance. Oxidation requires the addition of a large amount of oxidant, which is expensive to treat. It is difficult to effectively remove complexing agents such as sodium citrate in winter when the temperature is low. As a result, the concentration of heavy metal ions in the treated wastewater often cannot meet the requirements of the discharge standards for electroplating pollutants.

[0004]Diethylene triamine and other aliphatic polyamines and hydroxyl-containing organic amine complexing agents are extremely strong in oxidation resistance, which cannot be removed by conventional oxidation methods complexing agent, which brings great difficulties to the treatment of electroplating wastewater

[0008]At present, the electroplating industrial park adopts a centralized treatment method to treat electroplating wastewater. Various electroplating wastewater are mixed and discharged into the electroplating wastewater treatment plant for unified treatment. The composition of the wastewater is complex and the treatment is difficult. , it is very difficult to meet all the indicators of the processing results

Although great progress has been made in the treatment of electroplating wastewater after more than 10 years of technological transformation, the difficulty of meeting the standards for some heavy metal ions and the continuous rise in treatment costs pose severe challenges to the electroplating industry

Images