Study On Electrodeposition Of Electroplating Nickel Recovery Liquid

In the plating process, plating rinse cleaning generated wastewater containing heavy metal ions. By ion exchange or membrane treatment technology, it can be reused as the recovered liquid. After advanced treatments, the recovered liquid would be reused into plating process. Achieve the reuse of nickel recovered liquid in all-optical nickel plating process is the main goal of this thesis.Due to the deficiencies of existing advanced treatments, the quality of nickel plating is affected by impure decontamination liquid, exploring more effective purification technology is necessary. As a widely used purification technology, electrodialysis has the effect of separating and concentrating. In this paper, the treatment of nickel plating recovered liquid by electrodialysis was studied. Not only reduces the impurity content, nickel content has increased dramatically in the obtained nickel decontamination liquid, which achieve the purpose of edulcoration and concentration. To sum up, the main work done by this paper are:1. The treatment of simulation nickel recovered liquid by electrodialysis. The results of selection experiment showed BJT type ion exchange membrane had the best property for this study among four kinds of membrane. Optimization experiments showed that the voltage is the main factor of electrodialysis process. Increasing voltage made accelerating separation rate of nickel ions and electrodialysis process efficiency. When solution initial Ni²⁺concentration was 2 g/L, the voltage was 7.5 V, desalination and concentrate chambers’ flow were both 8 L/h, Ni²⁺ concentration in concentration chamber could reach 8.39 g/L.2. The treatment of plating nickel recovered liquid by electrodialysis. The results showed that with the increase of the running time, COD relative removal efficiency increases; and with the increase of initial concentration, COD relative removal rate decreases. When initial Ni²⁺ concentration was 2 g/L, COD relative removal rate reached 65.11%, Ni²⁺ concentration up to 3.38 times; final organics relative removal rate was 46.46%, corresponding to the COD value of 637.6 mg/L after the electrodialysis treatment. When the initial Ni²⁺ concentration of the concentrate chamber was 5 g/L, the relative removal rate of organic matter was 57.24%, and the rate of nickel ions separation and concentration at this time were 66.67% and 5.49 times.3. Hull cell test. The main factor of this test was the concentration of organic matter. The results showed that with the increase of COD concentration in the bath, the appearance quality of coated sheets decreased and coating thickness was decreasing as well. Those revealed that the concentration of organic matter not only affect the appearance of the coated sheets, but also had a certain degree of influence on the coating thickness. With the increase of COD concentration, the lower zone of coated sheets gradually became black. When the ratio of decontamination fluid and fresh bath solution was 1:9, the plated sheet showed no significant difference in the appearance with the original plating one, which meets the production requirements. The current COD value was 85.74 mg/L. Experimental results demonstrated that the nickel decontamination liquid had no effect on quality when recycled to the plating tank plating in appropriate proportion.