CN116397234A - Green and efficient stripping method for gold plating on surface of circuit board leftover material - Google Patents
Green and efficient stripping method for gold plating on surface of circuit board leftover material Download PDFInfo
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- CN116397234A CN116397234A CN202310338603.1A CN202310338603A CN116397234A CN 116397234 A CN116397234 A CN 116397234A CN 202310338603 A CN202310338603 A CN 202310338603A CN 116397234 A CN116397234 A CN 116397234A
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 100
- 229910052737 gold Inorganic materials 0.000 title claims abstract description 99
- 239000010931 gold Substances 0.000 title claims abstract description 99
- 239000000463 material Substances 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000007747 plating Methods 0.000 title claims abstract description 29
- 239000007788 liquid Substances 0.000 claims abstract description 29
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims abstract description 12
- 238000006243 chemical reaction Methods 0.000 claims description 17
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 14
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 10
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 3
- LCPVQAHEFVXVKT-UHFFFAOYSA-N 2-(2,4-difluorophenoxy)pyridin-3-amine Chemical compound NC1=CC=CN=C1OC1=CC=C(F)C=C1F LCPVQAHEFVXVKT-UHFFFAOYSA-N 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical group [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 2
- CHQMHPLRPQMAMX-UHFFFAOYSA-L sodium persulfate Substances [Na+].[Na+].[O-]S(=O)(=O)OOS([O-])(=O)=O CHQMHPLRPQMAMX-UHFFFAOYSA-L 0.000 claims description 2
- 239000002699 waste material Substances 0.000 abstract description 12
- 229910052751 metal Inorganic materials 0.000 abstract description 9
- 239000002184 metal Substances 0.000 abstract description 9
- 238000000926 separation method Methods 0.000 abstract description 6
- 239000000758 substrate Substances 0.000 abstract description 3
- 230000001590 oxidative effect Effects 0.000 abstract description 2
- 239000007800 oxidant agent Substances 0.000 abstract 1
- 235000021190 leftovers Nutrition 0.000 description 23
- 238000009713 electroplating Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000029087 digestion Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000706 filtrate Substances 0.000 description 5
- 229910000510 noble metal Inorganic materials 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 3
- 239000010953 base metal Substances 0.000 description 3
- 238000005868 electrolysis reaction Methods 0.000 description 3
- 238000003912 environmental pollution Methods 0.000 description 3
- -1 firstly Chemical compound 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229910021538 borax Inorganic materials 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 238000005272 metallurgy Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000004328 sodium tetraborate Substances 0.000 description 2
- 235000010339 sodium tetraborate Nutrition 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 239000011135 tin Substances 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- WLQXLCXXAPYDIU-UHFFFAOYSA-L cobalt(2+);disulfamate Chemical compound [Co+2].NS([O-])(=O)=O.NS([O-])(=O)=O WLQXLCXXAPYDIU-UHFFFAOYSA-L 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009854 hydrometallurgy Methods 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000120 microwave digestion Methods 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229960002635 potassium citrate Drugs 0.000 description 1
- 239000001508 potassium citrate Substances 0.000 description 1
- QEEAPRPFLLJWCF-UHFFFAOYSA-K potassium citrate (anhydrous) Chemical compound [K+].[K+].[K+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O QEEAPRPFLLJWCF-UHFFFAOYSA-K 0.000 description 1
- 235000011082 potassium citrates Nutrition 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- YWYZEGXAUVWDED-UHFFFAOYSA-N triammonium citrate Chemical compound [NH4+].[NH4+].[NH4+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O YWYZEGXAUVWDED-UHFFFAOYSA-N 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention discloses a green high-efficiency stripping method for gold plating on the surface of circuit board leftover materials; the method comprises the following specific steps: firstly, persulfate and a strong oxidant are mixed according to a certain proportion to prepare gold removing liquid, then, the circuit board leftover materials and the gold removing liquid are fully reacted at a certain temperature, the purpose of falling off the surface gold-plating layer is achieved by dissolving the attached metal under the gold-plating layer of the circuit board leftover materials through the gold removing liquid, and finally, the elemental gold is obtained after solid-liquid separation, so that the selective green efficient separation of gold in the circuit board leftover materials is realized. The method provided by the invention has the advantages of high separation efficiency, simplicity in operation, no secondary pollution, low operation cost and the like, and is also suitable for stripping the gold-plated layer on the surface of the substrate obtained after the components of the waste circuit board are removed.
Description
Technical Field
The invention belongs to the technical field of renewable resource processing and comprehensive utilization thereof, and particularly relates to a green and efficient stripping method for gold plating on the surface of circuit board leftover materials.
Background
Printed circuit boards are the basis of the electronics industry, and are found in essentially all electronic products in a wide variety and huge number; the printed circuit board has the characteristics of strong individuation, multiple manufacturing parameters and process characteristics, high precision requirement and the like, and the characteristics lead to easy scrapping in the production process of the printed circuit board, and the common scrapping rate is 5%. In 2019, the yield of PCB copper clad laminate in China is 6.83 hundred million square meters, and the scrapped circuit board is 3415 ten thousand square meters. As the period of electronic product update becomes shorter and shorter, the number of discarded printed circuit boards increases. Whether the circuit board scraps scrapped in production or the printed circuit boards scrapped after use are not properly processed, resources are wasted and the environment is seriously damaged.
The noble metal content in the waste circuit board is very high and can reach tens times or even hundreds times of that of natural ore. At present, three methods of fire method, wet method and biological metallurgy are mainly used for extracting noble metals from waste circuit boards, wherein the fire method metallurgy is abandoned gradually due to high cost, easy environmental pollution and the like. Hydrometallurgical processes are well established, which typically utilize solutions of strong oxidizing acids and the like as solvents to leach noble metals in one or more steps. Such as Wang Shuifa, cyanidation, etc. However, the cyanide is easy to cause great harm to the environment, and is extremely toxic, so that the cyanide is forbidden to be used in new projects. In summary, the efficient green extraction of noble metals has become an industrial difficulty and pain point.
Chinese patent CN201910599162 adopts a stripping and electrolysis method to extract gold, firstly, gold plating waste is put into a container containing stripping solution, and is electrically heated, so that gold is stripped from the surface of a plated part to saturation in the stripping solution, and gold-containing stripping solution is obtained. And then throwing the gold-containing gold-removing liquid into an electrolytic tank for electrolysis and heating, and simultaneously, introducing gas into the electrolytic tank to enable the gold-containing gold-removing liquid to surge, depositing gold on a cathode, and stripping flaky gold. The method realizes the recovery of gold in gold-plating waste, but in actual operation, gold is converted from a solid state into an ionic state and finally deposited into a solid state, the process is complicated, and the gold form conversion also generates loss.
Chinese patent CN201910380498.1 first breaks the circuit board to obtain a gold-bearing powder material. And then pretreating the gold-containing powder material by nitric acid to obtain gold-containing filter residues. Adding the gold-containing filter residue into aqua regia for digestion to obtain the gold-containing aqua regia. Finally, mixing the gold-containing aqua regia with the extract, extracting at least twice to obtain a gold-containing organic phase, and adding sodium sulfite for reduction to obtain the sponge gold. Although the extraction reduction rate of the method is higher, the operation is complex, the waste circuit board needs to be crushed, the extraction operation for multiple times in the process is complex, and the method is not suitable for actual production.
Chinese patent CN115125584a uses reverse electroplating to recover non-ferrous metals from waste circuit boards. And placing the waste circuit board into a carbon fiber cloth bag to be used as an anode for reverse electroplating. And taking the gold plate as a cathode for reverse electroplating, pouring gold electroplating solution into an electroplating bath, heating the electroplating solution to 40-50 ℃, controlling the current density of the reverse electroplating to be 0.8-1.2A/dm < 2 >, and the time of the reverse electroplating to be 15-20 minutes, taking out the carbon fiber cloth bag after the reverse electroplating, leaching with water, and stripping gold on a cathode plate. Wherein the solvent of the gold electroplating solution is deionized water, and the concentration of various solutes in the solution is respectively as follows: the concentration of potassium citrate is 5-8 g/L, the concentration of the ammonium citrate is 3-5 g/L, the concentration of thiourea is 8-10 g/L, the concentration of 1, 8-dihydroxynaphthalene-3, 6-disulfonic acid-2, 7-bis (azo-2-phenylarsonic acid) is 0.3-0.5 g/L, the concentration of cobalt sulfamate is 0.5-1 g/L, the concentration of crystal violet is 0.1-0.3 g/L, and the concentration of 4-amino-2- (methylsulfanyl) -5-thiophenecarboxylic acid is 0.1-0.3 g/L. The method can directly extract nonferrous metals such as tin, gold, palladium, silver, copper and the like in sequence according to different electrolytes. However, the electrolyte has complex composition components, and the reverse plating method has severe conditions, so that the production operation is inconvenient.
In summary, no matter reverse electrolysis or multiple extraction after strong acid gold melting can be realized, gold can not be extracted from circuit board scraps or waste circuit boards in a safe, environment-friendly and simple operation mode, and development of a green and efficient separation method with good selectivity is needed.
Disclosure of Invention
Aiming at the problems of high cost, high energy consumption and easy environmental pollution existing in the conventional method for extracting noble metals from leftover materials and waste circuit boards produced by circuit board production, the invention aims to provide a method for realizing gold plating stripping on the surfaces of leftover materials of circuit boards by dissolving attached metals (copper, nickel, manganese and the like) under the gold plating layer of the leftover materials of the circuit boards by gold stripping liquid. The circuit board leftover materials related by the invention are unusable circuit boards with gold-plated surfaces, are commonly used in high-end electronic equipment, and mainly contain metals such as gold, silver, copper, nickel, manganese, tin, zinc and the like. The method provided by the invention has the advantages of maximally extracting the gold-plated layer on the surface of the circuit board leftover material, realizing the selective green and efficient separation of gold in the circuit board leftover material, along with low operation cost, low energy consumption and low environmental pollution, high separation efficiency, simplicity in operation, no secondary pollution, low operation cost and the like, and is also suitable for stripping the gold-plated layer on the surface of the substrate obtained after the waste circuit board components are removed. The technical scheme of the invention is specifically introduced as follows.
A green and efficient stripping method for gold plating on the surfaces of circuit board leftover materials comprises the following steps:
(1) Mixing persulfate solution and 30wt.% hydrogen peroxide according to a certain proportion to prepare gold removing liquid;
(2) Placing the circuit board leftover materials into gold removing liquid, so that the circuit board leftover materials are fully soaked in the gold removing liquid;
(3) And (3) heating the solid-liquid mixture in the step (2) to 70-100 ℃ for reaction for 0.5-2 h, and completely stripping the gold-plating layer on the surface of the leftover material of the circuit board after the reaction is completed.
In the invention, in the step (1), the persulfate is one or a mixture of more than two of sodium persulfate, potassium persulfate or ammonium persulfate, the concentration of the persulfate solution is 0.5-2 mol/L, and the volume ratio of the hydrogen peroxide to the persulfate solution is 1:3-1:20. In the invention, the concentration of persulfate is 0.8-1.8 mol/L.
In the present invention, in step (1), 30wt.% of hydrogen peroxide is replaced with oxygen.
In the invention, in the step (2), the solid-liquid mass-volume ratio of the circuit board leftover materials to the gold removing liquid is 1:15-1:60 g/mL.
In the invention, in the step (3), ultrasound is applied in the reaction process to improve the shedding efficiency of the surface gold plating layer.
Compared with the prior art, the invention has the beneficial technical effects that:
(1) The method for stripping the gold plating on the surface of the circuit board leftover material provided by the invention does not damage the original circuit board structure, does not need to crush raw materials, reduces the production cost and simplifies the operation flow.
(2) According to the method for stripping the gold from the surface of the circuit board leftover material, the recovery rate of gold reaches more than 90% under the set optimal condition, the form of gold is not changed in the reaction, and the material loss is reduced.
(3) The method for stripping the gold on the surface of the circuit board leftover material provided by the invention has the advantages of simple operation method, less types of required reagents and no secondary pollution. And the byproducts have economic benefits, can improve project benefits, and have wide industrialized application prospects.
(4) The invention avoids the existing gold recovery technology based on aqua regia and highly toxic cyanide, adopts persulfate to dissolve the attached metal under the gold plating layer so as to peel off the gold plating layer, recovers gold in the form of simple substance metal, and can recycle gold stripping liquid without pollutant emission, thereby being green and economical.
Drawings
FIG. 1 is a flow chart of the process of stripping gold from the surface of the circuit board leftover material.
Fig. 2 is a diagram of a mobile phone jack in example 1 before gold plating is peeled off.
Fig. 3 is a diagram of a mobile phone jack in example 1 after gold plating is peeled off.
Fig. 4 is a diagram showing the falling off of the gold plating layer during the reaction of the circuit board scraps in example 2 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description is further provided with reference to examples.
FIG. 1 is a flow chart of a process for stripping gold from the surface of a circuit board leftover material, which specifically comprises the following steps:
after the circuit board leftover materials are soaked in the gold removing liquid, the reaction system is heated to 70-100 ℃ to fully react, the gold plating layer on the surface of the circuit board leftover materials is completely stripped after the reaction is finished, the circuit board leftover materials are taken away, and the rest part is filtered to obtain filtrate and filter residues; the filtrate can be used as solvent for recycling, after the base metal ions mainly containing copper in the filtrate are saturated, sulfate recovery and base metal (mainly containing copper) recovery can be carried out on the filtrate, the filter residue is cleaned and dried to obtain crude gold, borax is added into the crude gold under the high temperature condition to melt the crude gold into gold ingots, the base metal oxides contained in the crude gold react with the borax to generate low-melting-point substances, the low-melting-point substances float on the upper layer of the liquid, pure gold is arranged at the bottom, and the purification of the crude gold is realized.
Example 1
The waste circuit board in this embodiment is a mobile phone socket, and its mass is 0.45g. The dried sample is taken and placed in a digestion tank, 6mL of concentrated hydrochloric acid, 2mL of concentrated nitric acid and 2mL of deionized water are added, and then the digestion tank is placed in a microwave digestion instrument. After digestion, the volume was fixed to 100mL and the solutions were diluted 10-fold and 100-fold, respectively. The gold content of the metal component was 0.195% by quantitative measurement using ICP-OES (iCAP 7000) from thermoelectric (ThermoFisher Scientific) corporation, i.e., a cell phone plug containing 0.879mg gold.
17.5mL of ammonium persulfate solution with the concentration of 1.5mol/L and 30wt.% hydrogen peroxide with the concentration of 5mL are mixed, the solid-liquid mass-volume ratio of the circuit board to the gold removing solution is 1:50g/mL, water bath heating is adopted, and the reaction time is 1h. And after the reaction is finished, separating filter residues and filtrate by vacuum suction filtration, wherein the filter residues mainly comprise circuit board leftovers and stripped gold-plated layers, drying the filter residues after the circuit boards are taken away at the temperature of 100 ℃ for 24 hours, weighing, digesting the filter residues, and measuring the concentration of metal ions in the digestion liquid by ICP-OES and drying. The gold stripping rate is calculated to be 95.79% by measuring that the mass of gold is 0.842 mg. Fig. 2 and 3 are respectively diagrams of the mobile phone extension socket of example 1 before and after gold plating is stripped.
Example 2
Compared with the embodiment 1, the difference is that the solid-liquid mass-volume ratio is set to be 1:30g/mL, wherein the mass of the circuit board leftover material is 1.04g, the gold content in the circuit board is 0.3398mg through detection, and the gold removing effect of the gold removing liquid with different concentrations is shown in the table 1.
TABLE 1 Effect of gold-removing liquid at different concentrations
| Ammonium persulfate concentration (mol/L) | Gold mass (mg) | Gold stripping rate |
| 0.8 | 0.3214 | 94.59％ |
| 1.0 | 0.3228 | 95.00％ |
| 1.2 | 0.3273 | 96.32％ |
Fig. 4 is a diagram showing the falling off of the gold plating layer during the reaction of the circuit board scraps in example 2 of the present invention. In the figure, the circuit board is in the stage of finishing reaction in the gold removing liquid, and the figure clearly shows that the gold plating layer on the circuit board is already removed, the rest metals are already dissolved in the gold removing liquid, and the circuit board is already exposed out of the bottommost substrate.
Example 3
The difference compared with example 2 is that the concentration of ammonium persulfate solution is 0.8mol/L, and the gold removal effect at different reaction temperatures is shown in Table 2.
TABLE 2 gold removal effect at different reaction temperatures
| Reaction temperature (. Degree. C.) | Gold mass (mg) | Gold stripping rate |
| 70 | 0.3142 | 92.47％ |
| 80 | 0.3194 | 94.00％ |
| 90 | 0.3261 | 95.97％ |
。
Claims (6)
1. The green and efficient stripping method for gold plating on the surface of the circuit board leftover material is characterized by comprising the following steps of:
(1) Mixing persulfate solution and 30wt.% hydrogen peroxide according to a certain proportion to prepare gold removing liquid;
(2) Placing the circuit board leftover materials into gold removing liquid, so that the circuit board leftover materials are fully soaked in the gold removing liquid;
(3) And (3) heating the solid-liquid mixture in the step (2) to 70-100 ℃ for reaction for 0.5-2 h, and completely stripping the gold-plating layer on the surface of the leftover material of the circuit board after the reaction is completed.
2. The green and efficient stripping method for gold plating on the surfaces of circuit board scraps according to claim 1, wherein in the step (1), persulfate is one or a mixture of more than two of sodium persulfate, potassium persulfate or ammonium persulfate, the concentration of persulfate solution is 0.5-2 mol/L, and the volume ratio of hydrogen peroxide to persulfate solution is 1:3-1:20.
3. The green and efficient stripping method for gold plating on the surfaces of circuit board scraps according to claim 1, wherein the concentration of persulfate is 0.8-1.8 mol/L.
4. The method for efficiently stripping gold from a circuit board scrap surface according to claim 1, wherein 30wt.% of hydrogen peroxide is replaced with oxygen in the step (1).
5. The method for efficiently stripping gold from the surface of the circuit board leftover material according to claim 1, wherein in the step (2), the solid-liquid mass-volume ratio of the circuit board leftover material to the gold removing liquid is 1:15-1:60 g/mL.
6. The method for efficiently stripping gold from a surface of a circuit board scrap according to claim 1, wherein in the step (3), ultrasonic waves are applied during the reaction to improve the stripping efficiency of the surface gold plating.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310338603.1A CN116397234A (en) | 2023-03-31 | 2023-03-31 | Green and efficient stripping method for gold plating on surface of circuit board leftover material |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310338603.1A CN116397234A (en) | 2023-03-31 | 2023-03-31 | Green and efficient stripping method for gold plating on surface of circuit board leftover material |
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