Study On Deplating Process Of Chloride Salt System For ABS Plating Parts

Compared with metal parts,plastic electroplated products have the advantages of easy forming,good forming,light weight,corrosion resistance,wear resistance,and good appearance.In the plastic plating market,more than 90%of plastic plating products are ABS plastic plating products.Electroplating-grade ABS plastic can control the ratio of three components in ABS plastic to make it have good electroplating performance.Under normal circumstances,ABS substrates will be plated with different metal layers to meet different needs.The basic principle of plastic plating is to first deposit a conductive metal layer on the plastic surface by chemical methods,usually chemical copper or nickel plating,and then electroplating other metals on the plastic surface to form a surface decorative layer.Since the main use of ABS electroplated parts is protection and decoration,the plating layer is generally a composite plating layer such as copper-nickel-chromium,nickel-iron-chromium,etc.This coating structure makes the plastic electroplated parts both decorative and protective.With the continuous development of plastic electroplating technology and technology,the application fields of plastic electroplated parts,especially ABS electroplated parts,have been continuously expanded.At present,they are mainly used in electrical and electronic products,automobiles and bathrooms,and have been well received.Taking electrical and electronic products as an example,according to the data calculated by the China Household Electrical Appliances Research Institute,in 2018,the number of residents of electrical and electronic products in China reached 3.85 billion.Among them,the theoretical scrapped volume was58.886 million units,a total of 5.731 million tons.If such a large number of ABS electroplated parts can be reused,it can not only recycle metals and plastics,produce economic benefits,but also be beneficial to environmental protection.In this study,ABS plastic electroplated parts were used as the research object.The metal plating layer was removed by using the deplating solution,the metal was recovered,and the waste deplating solution that had lost the deplating effect was regenerated.The research contents mainly include the following aspects:（1）Study on the properties of the plating metal of ABS plastic plating parts.It has been proved through experiments that the samples of the plastic electroplating parts used in this research are mainly composed of three layers of metal,which are the topmost chromium,the bottommost copper and the middle nickel.（2）Screen out the best stripping solution and the best stripping solution.The three types of stripping solutions are ferric chloride stripping solution,copper chloride stripping solution,and copper chloride and ammonium chloride mixed solution stripping solution.Through single factor experiment and orthogonal experiment,ferric chloride deplating solution was selected as the best deplating solution for ABS plastic electroplating parts.The optimal conditions for the stripping of the ferric chloride stripping solution are 10%by mass of ferric chloride,a reaction temperature of 40°C,a reaction time of 30 minutes,and a liquid-solid ratio of 4.The stripping rate of this experimental scheme is greater than 95%.（3）Recycling the metal in the deplating solution.Metal chromium can be removed by filtration;metal copper and metal nickel can be replaced with iron filings.After filtration,it is removed from the deplating solution.The article explores the effects of the dilution ratio of the plating solution,the amount of iron filings,the reaction temperature,and the reaction time on the reduction rates of copper ions and nickel ions.When the reaction conditions are that the amount of iron filings added to the deplating solution is 1 times the number of moles of theoretically reduced Cu²⁺and Ni²⁺,the deplating solution is diluted 4 times,the reaction temperature is 60°C,the reaction time is 2h,and the reduction rate of Cu²⁺can reach 92%,and the reduction rate of Ni²⁺can reach 89%.（4）Regenerate the waste stripping solution.Hydrogen peroxide is oxidizing and can oxidize Fe²⁺in the spent stripping solution to Fe³⁺,thereby restoring the stripping solution’s deplating effect.The article explores the influence of the mass fraction of hydrogen peroxide and the volume of hydrogen peroxide added on the recovery efficiency of the waste stripping bath.The experimental results are as follows:the optimal hydrogen peroxide mass fraction for regenerating the waste stripping solution is 30%;the optimal hydrogen peroxide volume for regenerating the waste stripping solution is one third of the total volume of the regeneration stripping solution.