A persulfate stripping method for metal coating on the surface of discarded ABS electroplated parts

Abstract

The present invention discloses a method for stripping the metal coating on the surface of discarded ABS electroplated parts with persulfate, which belongs to the technical field of resource recycling. The method first pre-cleans the discarded ABS electroplated parts, and then places them in a composite persulfate solution system for ultrasonic reaction. After the reaction is completed, the parts are filtered and the obtained solids are washed to obtain ABS plastic. The method for stripping the metal coating on the surface of discarded ABS electroplated parts with persulfate of the present invention adopts a composite persulfate system as a stripping solution, thereby reducing damage to the plastic substrate, shortening the stripping cycle, achieving a high stripping rate, and ensuring a clean and efficient experimental process without secondary pollution. The method is green and environmentally friendly, effectively improving the secondary utilization value of the plastic, and the deplating solution of the present invention has simple components and is easy to recycle.

Description

Technical Field

[0001] The invention belongs to the technical field of resource recycling and utilization, and particularly relates to a persulfate stripping method for a metal coating on the surface of a discarded ABS electroplated part. Background Art

[0002] With the continuous development of urbanization, plastic electroplating parts are in huge demand due to their advantages such as light weight, low price, and strong durability. ABS plastic electroplating parts are widely used in various fields such as aviation, automobiles, electrical appliances, construction, and infrastructure. A large amount of discarded ABS electroplating parts is generated every year. If they are not effectively recycled and processed, not only will they waste resources and lose a large amount of precious metals such as copper and nickel, but the heavy metals on the surface will seep into the soil and groundwater, polluting the ecosystem near the dumping area and further affecting human life and health. Therefore, the proper treatment of ABS electroplating parts is not only environmentally friendly, but also can reuse resources and achieve certain economic benefits.

[0003] At present, the main methods for stripping discarded ABS electroplated parts are chemical, physical, biological and electrochemical methods. The chemical method has the advantages of high recovery rate and simple operation. However, the stripping solution used in the traditional chemical method is often a strong acid solution or ferric chloride solution, and the process is very easy to damage the plastic substrate. At the same time, the large amount of acid, alkali and high-valent iron increases the difficulty of subsequent disposal and also causes environmental pollution. The physical method will cause dust pollution during the instrument stripping operation, which is harmful to the human body and has a very low recovery rate; the biological method mainly uses Thiobacillus ferrooxidans to activate Fe 3+ The stripping process has the effect of oxidation, and the reaction is mild, but the stripping cycle is long and cannot meet production requirements; the electrochemical process is complex and the cost is high; in summary, it is difficult to balance economic benefits and environmental issues when stripping discarded ABS electroplated parts. Summary of the Invention

[0004] To solve the above-mentioned problems in the prior art, the present invention provides a new method for stripping the metal plating on the surface of discarded ABS electroplated parts. The method uses a composite persulfate as a stripping solution, which reduces damage to the plastic substrate, shortens the stripping cycle, and makes the experimental process clean and efficient, free of secondary pollution, environmentally friendly, and effectively improves the secondary utilization value of the plastic. At the same time, the stripping solution of the present invention has simple ingredients and is easy to recycle, which can effectively improve production efficiency and economic benefits and avoid environmental pollution problems caused by the treatment process.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a persulfate stripping method for a metal coating on a surface of a discarded ABS electroplated part, comprising the following steps:

[0007] Step 1: Clean and pre-treat the discarded ABS electroplating parts;

[0008] Step 2: placing the ABS electroplated part obtained by the pretreatment in step (1) into a composite persulfate solution system and subjecting it to ultrasonic reaction; after the reaction is completed, filtering and washing the obtained solid to obtain ABS plastic.

[0009] Furthermore, the waste ABS electroplated parts are copper-nickel-chromium metal-plated plastic parts.

[0010] Furthermore, in step 1, the cleaning pretreatment method is: soaking the discarded ABS electroplated parts in a cleaning solution for 15 to 30 minutes, taking them out and tearing off the colloid on the surface.

[0011] Furthermore, the cleaning liquid is N,N-dimethylformamide solution or ethanol. Preferably, the cleaning liquid is N,N-dimethylformamide solution.

[0012] N,N-dimethylformamide can dissolve surface colloids more quickly than ethanol in pretreatment of waste ABS electroplating parts.

[0013] Furthermore, the composite persulfate solution system in step 2 is a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5.

[0014] Furthermore, in the composite persulfate solution system, the concentration of (NH4)2S2O8 is 0.4-2.0 mol / L, the concentration of Na2S2O8 is 0.1-1.5 mol / L, and the concentration of KHSO5 is 0.1-1.5 mol / L.

[0015] Further preferably, the molar concentration of the (NH4)2S2O8 solution is 0.5-1.4 mol / L, the molar concentration of the Na2S2O8 solution is 0.1-0.9 mol / L, and the molar concentration of KHSO5 is 0.1-0.9 mol / L.

[0016] Further preferably, the mass concentration of the (NH4)2S2O8 solution is 0.6-1.2 mol / L, the molar concentration of the Na2S2O8 solution is 0.3 mol / L, and the molar concentration of KHSO5 is 0.4 mol / L.

[0017] Furthermore, in step 2, the mass volume ratio of the pretreated ABS electroplated part to the composite persulfate solution system is 1 kg: (3-18) L, the reaction time of the ultrasonic reaction is 0.25-2.0 h, the reaction temperature is 20-70° C., and the ultrasonic frequency is 20-40 KHz.

[0018] Further preferably, in step 2, the mass volume ratio of the pretreated ABS electroplated part to the composite persulfate solution system is 1 kg: (5-12) L, the reaction time of the ultrasonic reaction is 0.25-1.5 h, the reaction temperature is 25-65° C., and the ultrasonic frequency is 20-40 kHz.

[0019] Further preferably, in step 2, the mass volume ratio of the pretreated ABS electroplated part to the composite persulfate solution system is 1 kg: (7-10) L, the reaction time of the ultrasonic reaction is 0.25-1.2 h, the reaction temperature is 25-60° C., and the ultrasonic frequency is 20-40 KHz.

[0020] Further preferably, in step 2, the mass volume ratio of the pretreated ABS electroplated part to the composite persulfate solution system is 1 kg: (7-10) L, the reaction time of the ultrasonic reaction is 0.25-1.0 h, the reaction temperature is 25-55° C., and the ultrasonic frequency is 20-40 KHz.

[0021] Furthermore, the stripping solution obtained by filtration in step 2 is subjected to extraction to recover copper, and the stripping solution after copper recovery is subjected to electrolysis to recover nickel.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention uses a composite persulfate as a deplating solution. Without any treatment, the persulfate generates persulfate radicals, which are generally oxidizing, in water. However, after certain activation treatments, the persulfate can generate highly oxidizing persulfate radicals. Therefore, the present invention uses ultrasound to activate the persulfate to generate highly oxidizing persulfate radicals, achieving the stripping of metal coatings on discarded ABS electroplated parts. While conventional thermal activation requires a persulfate bath temperature above 60°C, ultrasonic activation effectively reduces the effects of high temperatures on plastics and is convenient and easy to operate.

[0024] The present invention adopts a non-acidic and ferric chloride system, has mild reaction conditions, is simple and convenient to operate, is clean and efficient, and reduces damage to the plastic substrate compared to an acidic stripping solution. The stripping components are simple and the reagents are inexpensive. When the metal is recovered later, compared to a ferric chloride stripping solution, no large amount of difficult-to-treat metal ions are introduced. The method can almost completely strip the metal coating, and the stripping rate can reach more than 99% under a relatively short stripping cycle. The grade of the ABS plastic substrate used as a recycled material is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a process flow chart of Example 1;

[0027] Figure 2 : are comparison diagrams of the obtained plastic substrates, wherein A is the appearance diagram of the stripped and recycled plastic obtained in Example 4, and B is the appearance diagram of the stripped and recycled plastic obtained in Comparative Example 3. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0029] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in the stated range is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0031] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0032] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0033] Example 1

[0034] Waste ABS electroplated parts (mass denoted as m) were placed in an N,N-dimethylformamide solution for immersion and cleaning for 30 minutes, and the surface colloid was removed to obtain the cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-to-solid volume mass ratio of 10 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.7 mol / L, the concentration of Na2S2O8 was 0.1 mol / L, and the concentration of KHSO5 was 0.2 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 35°C for 25 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-solid volume mass ratio of 10 L / Kg to completely strip the plating. After the reaction was completed, the substrate was filtered to obtain a solid that was completely stripped of the ABS plastic substrate and flaky metal chromium. The solid was then washed to remove the flaky metal chromium, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times. The calculation formula is as follows:

[0035]

[0036] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling. The process flow chart is as follows: Figure 1 .

[0037] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 88.53%.

[0038] Example 2

[0039] Waste ABS electroplated parts (mass denoted as m) were placed in an N,N-dimethylformamide solution for immersion and cleaning for 30 minutes, and the surface colloid was removed to obtain cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-solid volume mass ratio of 8 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.3 mol / L, the concentration of Na2S2O8 was 0.3 mol / L, and the concentration of KHSO5 was 0.3 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 45°C for 40 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 8 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0040] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0041] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 92.82%.

[0042] Example 3

[0043] Waste ABS electroplated parts (mass denoted as m) were placed in an N,N-dimethylformamide solution for immersion and cleaning for 30 minutes, and the surface colloid was removed to obtain the cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-solid volume mass ratio of 6 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.9 mol / L, the concentration of Na2S2O8 was 0.1 mol / L, and the concentration of KHSO5 was 0.1 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 35°C for 40 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 6 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0044] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0045] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 95.58%.

[0046] Example 4

[0047] Waste ABS electroplated parts (mass denoted as m) were placed in an N,N-dimethylformamide solution for immersion and cleaning for 30 minutes, and the surface colloid was removed to obtain the cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-to-solid volume mass ratio of 8 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.7 mol / L, the concentration of Na2S2O8 was 0.3 mol / L, and the concentration of KHSO5 was 0.4 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 40°C for 45 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 8 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0048] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0049] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 99.87%.

[0050] The appearance of the stripped and recycled plastic obtained in this embodiment is shown in FIG. Figure 2 As shown in Figure A.

[0051] Example 5

[0052] Waste ABS electroplated parts (mass denoted as m) were placed in an N,N-dimethylformamide solution for immersion and cleaning for 30 minutes, and the surface colloid was removed to obtain the cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-solid volume mass ratio of 8 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.5 mol / L, the concentration of Na2S2O8 was 0.1 mol / L, and the concentration of KHSO5 was 0.2 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 50°C for 45 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 8 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0053] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0054] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 96.86%.

[0055] Example 6

[0056] Waste ABS electroplated parts (mass denoted as m) were immersed and cleaned in an N,N-dimethylformamide solution for 30 minutes, and the surface colloid was removed to obtain cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-to-solid volume mass ratio of 18 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8, and KHSO5, wherein the concentration of (NH4)2S2O8 was 2.0 mol / L, the concentration of Na2S2O8 was 0.1 mol / L, and the concentration of KHSO5 was 0.1 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 20°C for 120 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 18 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0057] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0058] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 94.20%.

[0059] Example 7

[0060] Waste ABS electroplated parts (mass denoted as m) were immersed and cleaned in an N,N-dimethylformamide solution for 30 minutes, and the surface colloid was removed to obtain cleaned ABS electroplated parts; 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-solid volume mass ratio of 3 L / Kg, wherein the composite persulfate system was a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5, wherein the concentration of (NH4)2S2O8 was 0.4 mol / L, the concentration of Na2S2O8 was 1.5 mol / L, and the concentration of KHSO5 was 1.5 mol / L; then, the parts were placed in an ultrasonic cleaner and reacted at a temperature of 70°C for 30 minutes at an ultrasonic frequency of 40 kHz; after the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 3 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0061] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0062] The calculation shows that the stripping rate of the metal on the surface of the ABS electroplated fragments is 99.76%.

[0063] Comparative Example 1

[0064] Waste ABS electroplated parts (mass denoted as m) were immersed in an N,N-dimethylformamide solution for 30 minutes to obtain cleaned ABS electroplated parts. 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution at a liquid-to-solid volume ratio of 8 L / kg, stirred for 30 minutes at 40°C. The composite persulfate solution consisted of a composite solution of (NH4)2S2O8, Na2S2O8, and KHSO5, with a concentration of 0.7 mol / L (NH4)2S2O8, 0.3 mol / L Na2S2O8, and 0.4 mol / L KHSO5. After the reaction, the parts were filtered. The solids were washed to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 8 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0065] For the copper and nickel ions on the ABS surface after stripping, the stripping solution containing nickel ions is then subjected to chromium slag metal stripping solution, extraction (LIX-84i extractant) to obtain copper and cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0066] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 75.67%.

[0067] Comparative Example 2

[0068] Waste ABS electroplated parts (mass denoted as m) were immersed in an N,N-dimethylformamide solution for cleaning for 30 minutes, and the surface colloid was removed to obtain cleaned ABS electroplated parts. 100 g of the cleaned ABS electroplated parts were placed in a composite persulfate solution system at a liquid-to-solid volume mass ratio of 8 L / Kg, wherein the composite persulfate system was a composite solution of K2S2O8, Na2S2O8, and KHSO5, wherein the concentration of K2S2O8 was 0.7 mol / L, the concentration of Na2S2O8 was 0.3 mol / L, and the concentration of KHSO5 was 0.4 mol / L. The parts were then placed in an ultrasonic cleaner and reacted at a temperature of 40°C for 45 minutes at an ultrasonic frequency of 40 kHz. After the reaction, the parts were filtered, the solids were cleaned to remove flaky metallic chromium, dried, and weighed (denoted as m1). Then, the substrate was placed in the same composite persulfate solution system as above at a liquid-to-solid volume mass ratio of 8 L / Kg for complete stripping. After the reaction was completed, the substrate was filtered to obtain a completely stripped ABS plastic substrate and flaky chromium metal. The solid was then washed to remove the flaky chromium metal, dried, and weighed (recorded as m2). The stripping rate η was then calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0069] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0070] The calculation shows that the stripping rate of metal on the surface of ABS electroplated parts is 60.45%.

[0071] Comparative Example 3

[0072] Waste ABS electroplating parts (mass is recorded as m) are placed in N,N-dimethylformamide solution for immersion and cleaning, soaked for 30 minutes, taken out and torn off the surface colloid to obtain the cleaned ABS electroplating parts; 100g of the cleaned ABS electroplating parts are placed in a 15% nitric acid deplating solution system according to a liquid-to-solid volume mass ratio of 8L / Kg; then they are placed in an ultrasonic cleaner and reacted at a temperature of 40°C for 45 minutes at an ultrasonic frequency of 40KHz; after the reaction is completed, the solids are filtered, the flaky metal chromium is removed, dried, and weighed (recorded as m1). Then, according to the liquid-to-solid volume mass ratio of 8L / Kg, the solids are placed in a 15% nitric acid deplating solution system with the same mass fraction as above to completely strip the parts; after the reaction is completed, the solids are filtered to obtain completely stripped ABS plastic substrates and flaky metal chromium, the solids are then cleaned to remove the flaky metal chromium, dried, and weighed (recorded as m2), and the stripping rate η is calculated based on the mass difference between the two stripping times, using the same calculation formula as in Example 1.

[0073] For the stripping solution containing copper and nickel ions on the ABS surface after stripping, copper is extracted (LIX-84i extractant) to obtain copper, and then the stripping solution containing nickel ions is subjected to cyclone electrolysis to obtain metallic nickel. After the metal is recovered, the stripping solution is returned for recycling.

[0074] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 98.87%.

[0075] The appearance of the stripped and recycled plastic obtained in this embodiment is shown in FIG. Figure 2 As shown in Figure B.

[0076] Comparative Example 4

[0077] The waste ABS electroplating parts (mass is m) are placed in an ethanol solution for immersion and cleaning for 30 minutes. The surface colloid is removed to obtain the cleaned ABS electroplating parts. The remaining steps are the same as those in Example 4.

[0078] The calculation shows that the stripping rate of metal on the surface of ABS electroplated fragments is 95.25%.

[0079] In this comparative example, ethanol solution was used to clean the waste ABS electroplated parts. However, compared with the use of N,N-dimethylformamide solution to clean the waste ABS electroplated parts, the surface colloid was dissolved more slowly. Therefore, after the same 30-minute immersion, the surface colloid could not be completely dissolved. Ultimately, the stripping rate of the metal on the surface of the ABS electroplated part fragments was not as high as that after the waste ABS electroplated parts were cleaned with N,N-dimethylformamide solution.

[0080] The above description is only a preferred specific embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed in the present invention, and these changes should be covered by the protection scope of the present invention.

Claims

1. A persulfate stripping method for the metal coating on the surface of discarded ABS electroplated parts, characterized in that: The following steps are involved: Step 1: pre-cleaning the waste ABS electroplating parts; the pre-cleaning method is: soaking the waste ABS electroplating parts in a cleaning solution for 15 to 30 minutes, taking them out and removing the colloid on the surface; the cleaning solution is N,N-dimethylformamide or ethanol; Step 2: placing the ABS electroplated part obtained by pretreatment in step (1) into a composite persulfate solution system and subjecting it to ultrasonic reaction; after the reaction is completed, filtering and washing the obtained solid to obtain ABS plastic; the composite persulfate solution system is a composite solution of (NH4)2S2O8, Na2S2O8 and KHSO5; in the composite persulfate solution system, the concentration of (NH4)2S2O8 is 0.4mol / L~2.0mol / L, the concentration of Na2S2O8 is 0.1~1.5mol / L, and the concentration of KHSO5 is 0.1~1.5mol / L; the reaction time of the ultrasonic reaction is 0.25~2.0h, the reaction temperature is 20~70℃, and the ultrasonic frequency is 20~40kHz.

2. The persulfate stripping method for the metal plating layer on the surface of waste ABS electroplated parts according to claim 1, characterized in that: The discarded ABS electroplated parts are copper-nickel-chromium metal-plated plastic parts.

3. The persulfate stripping method for the metal plating layer on the surface of waste ABS electroplated parts according to claim 1, characterized in that: In the composite persulfate solution system, the concentration of (NH4)2S2O8 is 0.5-1.4 mol / L, the concentration of Na2S2O8 is 0.1-0.9 mol / L, and the concentration of KHSO5 is 0.1-0.9 mol / L.

4. The persulfate stripping method for the metal plating layer on the surface of waste ABS electroplated parts according to claim 1, characterized in that: In the composite persulfate solution system, the concentration of (NH4)2S2O8 is 0.6-1.2 mol / L, the concentration of Na2S2O8 is 0.3 mol / L, and the concentration of KHSO5 is 0.4 mol / L.

5. The persulfate stripping method for the metal plating layer on the surface of waste ABS electroplated parts according to claim 1, characterized in that: In step 2, the mass volume ratio of the pre-treated ABS electroplated part to the composite persulfate solution system is 1 kg: (3-18) L.

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