Treatment method of chemical nickel plating waste liquid

Abstract

A treatment method of chemical nickel plating waste liquid comprises the following steps: (1) adding calcium hydroxide into the chemical nickel plating waste liquid to react, and filtering to obtain primary filtrate and filter residues 1; (2) adding calcium hydroxide into the primary filtrate, introducing ozone for oxidation reaction, and filtering to obtain oxidized filtrate and filter residues 2; (3) adding calcium hydroxide into the oxidized filtrate to react, and filtering to obtain standard filtrate and filter residues 3; (4) combining the filter residues 1, 2 and 3, adding a sulfuric acid solution for leaching, and filtering to obtain nickel sulfate primary filtrate and filter residues 4; (5) adding sodium fluoride into the nickel sulfate primary filtrate for reaction, adjusting thepH value, standing and filtering to obtain nickel sulfate filtrate and calcium fluoride slag; (6) adding zirconium sulfate into the nickel sulfate filtrate to react, standing and filtering to obtain anickel sulfate purified solution and zirconium phosphate slag; and (7) adjusting the pH value of the nickel sulfate purified solution, reacting, and filtering. The method is high in wastewater treatment efficiency, free of secondary discharge, capable of recycling nickel, simple in process, low in cost and suitable for industrial treatment.

Description

technical field [0001] The invention relates to a treatment method for waste liquid, in particular to a treatment method for electroless nickel plating waste liquid. Background technique [0002] Electroless nickel plating is a finishing method in which nickel and phosphorus coatings are formed by the action of nickel salt and hypophosphite. Electroless nickel plating has the advantages of uniformity, no need for external power supply, high hardness, good wear resistance, and plating is not limited by the size and shape of parts, and is widely used in various fields. [0003] In order to improve the quality of the nickel plating layer, the stability and service life of the plating solution, complexing agents, stabilizers, accelerators, pH buffers and brighteners need to be added to the plating solution, all of which are organic substances, such as citric acid , tartaric acid, malic acid, glycolic acid, succinic acid, succinic acid, acetic acid, etc. Moreover, a large amoun...

AI Technical Summary

Problems solved by technology

However, its disadvantage is that the chemical Fenton method will produce a large amount of nickel-iron slag, which needs to be treated separately, and it is difficult to reduce the COD of wastewater from 5000 to 8000 mg / L is reduced to below 800 mg / L; if the COD cannot be reduced below 800 mg / L, the service life of the electrodialysis membrane and reverse osmosis membrane will be reduced, scaling and other problems will occur, and the concentrated water will be returned to the chemical Fenton method for treatment , it is obviously difficult to achieve water balance, and it is even more difficult to achieve the treatment of high COD electroless nickel plating wastewater

However, the technical defects of this process are: 1) the whole process and time are too long; 2) the smell of sodium sulfide is strong, if sodium sulfide is excessive, it will increase the alkalinity of water, if it is neutralized with acid, it will produce toxic Gas hydrogen sulfide, but not too much, nickel can not be removed; 3) ammonia nitrogen is not absorbed after blowing off; 4) if nickel ions are not completely removed, or there are chloride ions with a concentration ≥ 300mg / L in the wastewater, then anaerobic - Part of the aerobic bacteria will be poisoned to death, and the treatment effect will be poor; 5) The adaptable temperature of anaerobic-aerobic bacteria is 10-35°C, which is not suitable for winter and summer; 6) The particle size of nickel sulfide is extremely small and will float on the surface on the water

Images