Method for treating complex-containing nickel plating wastewater

Abstract

The invention discloses a method for treating complex-containing nickel plating wastewater, which is characterized by comprising the following steps of: adding an oxidant into the wastewater to be treated under the acidic condition to ensure that a nickel ion complex in the wastewater is subjected to oxidative damage by the oxidant and nickel ions are free; after the complex is damaged by the oxidation process, regulating the pH value by using an alkaline solution to make the nickel ions generate a hydroxide precipitate; adding dilute acid into the hydroxide precipitate for dissolving, concentrating, crystallizing, and recovering nickel salt; and adding dilute acid into the wastewater from which nickel is removed to regulate the pH, and adding a precipitating agent to remove phosphite and phosphate. The process that the pH of the wastewater is changed by a chemical method and heavy metal ions to be removed are precipitated and dissolved is adopted, so that the secondary pollution of the wastewater is avoided, the ions are completely precipitated, aftertreatment cost is low, the wastewater does not contain phosphorus, and economic benefits and environment friendliness are unified.

Description

technical field [0001] The invention relates to a method for recycling and treating nickel-plating wastewater, in particular to a method for treating complex-containing nickel-plating wastewater. Background technique [0002] The process of plating a layer of nickel on metal or non-metal by electrolysis or chemical method is called nickel plating. Nickel plating is divided into electroplating nickel plating and chemical nickel plating. Nickel electroplating is in an electrolyte composed of nickel salt (called main salt), conductive salt, pH buffer, and wetting agent. The anode uses metallic nickel, the cathode is the plated part, and direct current is applied to the cathode (plated part). Deposit a uniform and dense nickel coating. Bright nickel is obtained from the bath with brightener, and dark nickel is obtained from the electrolyte without brightener. Electroless nickel plating is a method of obtaining a nickel plating layer on the surface of a material through a self...

AI Technical Summary

Problems solved by technology

After the waste liquid is discharged, on the one hand, it seriously pollutes the environment, and on the other hand, it causes a waste of nickel resources, so the pollution to the environment is very serious

Among them, nickel often exists in the form of complexes, and it is difficult to discharge up to the standard by precipitant precipitation alone. Sometimes there are ammonium ions in the actual waste liquid, which will form nickel-ammonium complexes under the action of hydroxide. Even if the pH is high, it is difficult Precipitation; and nickel plating wastewater contains phosphorus, which belongs to eutrophic elements and should be removed

[0005] The Chinese patent number is 200810205037.8, and the title of the patent is "the treatment method of nickel-plating waste liquid and nickel-plating rinsing wastewater containing complexes", which is a method of using ion exchange resin to remove nickel from wastewater. This method costs too much High, and nickel removal is not complete