Study On Electrochemical Regeneration Of Electroless Nickel Waste

The electroless nickel plating technology that use hypophosphite as reducing agent obtained widespread application in various industrial fields because of its good wear resistance、corrosion resistance and coating thickness of the advantages of uniform. However, existing electroless nickel plating solution life is generally not more than ten cycles, which makes chemical nickel-plated high cost of the waste if not dealt with direct emissions of harmful substances in the waste will pollute the environment, destroy ecological balance, useful substances contained in the waste can also cause waste of resources. The subject from the point of view of the protection of the environment, conserve resources, seeking an effective chemical nickel plating wastewater regeneration method to further improve the regeneration of waste, to extend the service life of the bath, and thus reduce the cost of electroless nickel favorable and rational use of resources.In this paper, on the basis of prior electrodialysis renewable chemical nickel plating wastewater, further research electrodialysis regeneration of electroless nickel waste; direct electrochemical conversion into phosphate waste liquid phosphate in Central Asia and the electrodialysis regeneration anode waste recovery study of membrane electrolysis Electrodialysis experiment select removal performance factors affecting ion, the ion exchange membrane selection and process parameters were studied, obtained a suitable ion-exchange membrane and process parameters; examines the feasibility of a the phosphite direct electrochemical conversion into phosphate; also studied electrodialysis anode waste recycling.The electrodialysis experiment, three pairs of ion-exchange membrane of a comparative study of Guangdong electroless nickel plating plant waste, operating current density, temperature, material flow and process factors such as waste regeneration performance. Experimental results show that exchange membrane and Shanghai hetero-phase composed of an anion exchange membrane membrane capsule CMS C outperforms the other two pairs of film; Suitable process conditions J=65mA/cm2and a temperature of26degrees Celsius, membrane spacing5cm, desalination chamber material flow for0.02L/s:continued to add water, and the solution was diluted approach is conducive to the conduct of the experiment. but the loss of nickel ion is not particularly meaningful:Technological conditions for J=65mA/cm2at a temperature of37degrees centigrade, with the film at5cm, play down the material flow for dealing with liquid waste under the condition of0.02L/s48h, removal of harmful components in phosphorous acid rate of60.86%,63.13%phosphate loss rate, loss of nickel ion is1.2%, this regeneration bath after you add the components for performance testing showed that the plated speed of10.28μm/h, a phosphorus content of9.7%, coating hardness538HV, the mere mention of resistance and salt spray test to meet its production needs; regeneration bath coating obtained with the new open cylinder plating bath third cycle of morphology and phosphorus content also substantially similarElectrochemical conversion of phosphite experiment by cathodic polarization experiments metal indium as the working electrode, cyclic voltammetry tests show the feasibility of the conversion, after12h of electrolysis experiments confirmed, phosphite conversion rate reached7.5%.Finally, the anode chamber solution in the electrodialysis membrane electrolytic recovery, obtained a better recovery process parameters for J=60mA/cm2, pH8, the flow rate of0.018L/s, membrane electrolysis after2h recovery, phosphate recovery rate of56.68%.