CN116446029A - Method and device for withdrawing tin and recovering tin simultaneously for PCB (printed circuit board) in one step - Google Patents
Method and device for withdrawing tin and recovering tin simultaneously for PCB (printed circuit board) in one step Download PDFInfo
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- CN116446029A CN116446029A CN202310474416.6A CN202310474416A CN116446029A CN 116446029 A CN116446029 A CN 116446029A CN 202310474416 A CN202310474416 A CN 202310474416A CN 116446029 A CN116446029 A CN 116446029A
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- tin
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- acid
- electrolytic
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 title claims abstract description 177
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000006243 chemical reaction Methods 0.000 claims abstract description 14
- 230000008878 coupling Effects 0.000 claims abstract description 11
- 238000010168 coupling process Methods 0.000 claims abstract description 11
- 238000005859 coupling reaction Methods 0.000 claims abstract description 11
- 230000005684 electric field Effects 0.000 claims abstract description 11
- 238000011084 recovery Methods 0.000 claims abstract description 8
- 238000005728 strengthening Methods 0.000 claims abstract description 7
- 229910001432 tin ion Inorganic materials 0.000 claims abstract description 7
- 230000002378 acidificating effect Effects 0.000 claims abstract description 5
- 230000009471 action Effects 0.000 claims abstract description 3
- 238000007747 plating Methods 0.000 claims description 16
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 14
- 239000002253 acid Substances 0.000 claims description 11
- 230000007797 corrosion Effects 0.000 claims description 11
- 238000005260 corrosion Methods 0.000 claims description 11
- 239000002270 dispersing agent Substances 0.000 claims description 9
- 239000003112 inhibitor Substances 0.000 claims description 9
- 239000003381 stabilizer Substances 0.000 claims description 8
- JWAZRIHNYRIHIV-UHFFFAOYSA-N 2-naphthol Chemical compound C1=CC=CC2=CC(O)=CC=C21 JWAZRIHNYRIHIV-UHFFFAOYSA-N 0.000 claims description 6
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 claims description 6
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 4
- 239000012964 benzotriazole Substances 0.000 claims description 4
- 239000002639 bone cement Substances 0.000 claims description 4
- -1 polyoxyethylene Polymers 0.000 claims description 4
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 claims description 4
- KKVTYAVXTDIPAP-UHFFFAOYSA-M sodium;methanesulfonate Chemical compound [Na+].CS([O-])(=O)=O KKVTYAVXTDIPAP-UHFFFAOYSA-M 0.000 claims description 4
- WXHLLJAMBQLULT-UHFFFAOYSA-N 2-[[6-[4-(2-hydroxyethyl)piperazin-1-yl]-2-methylpyrimidin-4-yl]amino]-n-(2-methyl-6-sulfanylphenyl)-1,3-thiazole-5-carboxamide;hydrate Chemical compound O.C=1C(N2CCN(CCO)CC2)=NC(C)=NC=1NC(S1)=NC=C1C(=O)NC1=C(C)C=CC=C1S WXHLLJAMBQLULT-UHFFFAOYSA-N 0.000 claims description 3
- BZOVBIIWPDQIHF-UHFFFAOYSA-N 3-hydroxy-2-methylbenzenesulfonic acid Chemical compound CC1=C(O)C=CC=C1S(O)(=O)=O BZOVBIIWPDQIHF-UHFFFAOYSA-N 0.000 claims description 3
- CMGDVUCDZOBDNL-UHFFFAOYSA-N 4-methyl-2h-benzotriazole Chemical compound CC1=CC=CC2=NNN=C12 CMGDVUCDZOBDNL-UHFFFAOYSA-N 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 3
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 claims description 3
- 229950011260 betanaphthol Drugs 0.000 claims description 3
- 229940098779 methanesulfonic acid Drugs 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- WXMKPNITSTVMEF-UHFFFAOYSA-M sodium benzoate Chemical compound [Na+].[O-]C(=O)C1=CC=CC=C1 WXMKPNITSTVMEF-UHFFFAOYSA-M 0.000 claims description 3
- 235000010234 sodium benzoate Nutrition 0.000 claims description 3
- 239000004299 sodium benzoate Substances 0.000 claims description 3
- 235000002906 tartaric acid Nutrition 0.000 claims description 3
- 239000011975 tartaric acid Substances 0.000 claims description 3
- WHOZNOZYMBRCBL-OUKQBFOZSA-N (2E)-2-Tetradecenal Chemical compound CCCCCCCCCCC\C=C\C=O WHOZNOZYMBRCBL-OUKQBFOZSA-N 0.000 claims description 2
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 2
- 229940044654 phenolsulfonic acid Drugs 0.000 claims description 2
- 239000001509 sodium citrate Substances 0.000 claims description 2
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 claims description 2
- HWCKGOZZJDHMNC-UHFFFAOYSA-M tetraethylammonium bromide Chemical compound [Br-].CC[N+](CC)(CC)CC HWCKGOZZJDHMNC-UHFFFAOYSA-M 0.000 claims description 2
- 239000002351 wastewater Substances 0.000 abstract description 6
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 238000004064 recycling Methods 0.000 abstract description 2
- KKKAMDZVMJEEHQ-UHFFFAOYSA-N [Sn].[N+](=O)(O)[O-] Chemical compound [Sn].[N+](=O)(O)[O-] KKKAMDZVMJEEHQ-UHFFFAOYSA-N 0.000 abstract 1
- 239000011248 coating agent Substances 0.000 abstract 1
- 238000000576 coating method Methods 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 18
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 9
- 229910017604 nitric acid Inorganic materials 0.000 description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 8
- 229910052802 copper Inorganic materials 0.000 description 8
- 239000010949 copper Substances 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 7
- 239000002699 waste material Substances 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 238000009614 chemical analysis method Methods 0.000 description 5
- 229910002804 graphite Inorganic materials 0.000 description 5
- 239000010439 graphite Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- JOQGJRQKCIJIDB-UHFFFAOYSA-N tin;hydrochloride Chemical compound Cl.[Sn] JOQGJRQKCIJIDB-UHFFFAOYSA-N 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 239000007800 oxidant agent Substances 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 238000004070 electrodeposition Methods 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- 125000003354 benzotriazolyl group Chemical group N1N=NC2=C1C=CC=C2* 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 150000002391 heterocyclic compounds Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- LFLZOWIFJOBEPN-UHFFFAOYSA-N nitrate, nitrate Chemical compound O[N+]([O-])=O.O[N+]([O-])=O LFLZOWIFJOBEPN-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F5/00—Electrolytic stripping of metallic layers or coatings
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
- C25C1/14—Electrolytic production, recovery or refining of metals by electrolysis of solutions of tin
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F7/00—Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects; Servicing or operating
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
The invention discloses a method and a device for withdrawing tin and recovering tin of a PCB in one step; the etched circuit board is subjected to electrolytic tin stripping and tin recovery under the conditions of external field coupling strengthening and simultaneous action of a pulse electric field in an acidic system solution continuous tin stripping electrolytic reaction device; along with the progress of the reaction, the tin coating on the circuit board is completely dissolved into the solution, and tin ions in the solution are deposited and separated out at the cathode, so that high-quality cathode tin is obtained. The method effectively shortens the tin stripping time, efficiently recovers tin, simultaneously effectively solves the problem that the ammonia nitrogen wastewater yield of the traditional nitric acid tin stripping system is large and difficult to recycle, and has the advantages of cleanness, high efficiency and strong selectivity. The device is simple and practical, and can obtain better tin stripping and recycling effects when being matched with the device.
Description
Technical Field
The invention relates to a method and a device for withdrawing tin and recycling tin in one step of PCB, belonging to the field of nonferrous metal metallurgy.
Background
A Printed Circuit Board (PCB) is a support for electronic components, and its main function is to connect various types of electronic components to form a specific circuit, which is a key electronic interconnect for electronic products, and any electronic product or equipment needs to be equipped with the PCB. Printed circuit boards are significant for the development of the age, and the downstream industry has been concerned with covering all consumer electronics, including information, communications, medical, and even aerospace technology products.
The production of the PCB comprises 20 or more working procedures of cutting, drilling, grinding, copper deposition, electroplating, pattern transfer, copper plating, film stripping, etching and the like, wherein in order to avoid scrapping caused by the conditions of breaking, wire breakage and the like of a copper matrix pattern on the PCB during etching, the tin plating process is indispensable, and the tin plating layer is stripped after the pattern is manufactured. At present, most of domestic PCB production enterprises adopt nitric acid or nitric acid-alkyl sulfonic acid type tin stripping water for tin stripping.
However, due to the characteristics of instability and poor selectivity of nitric acid, and the like, after tin stripping is performed for many times, the property of the tin stripping water can be greatly changed, and the tin stripping water contains not only high-concentration tin ions (100-150 g/L) but also copper ions and iron ions (20-30 g/L) with certain concentration, and heterocyclic compounds, polycyclic aromatic compounds and other polymers can be gradually accumulated because of being incapable of being opened. At this time, the tin stripping solution can not continuously and effectively dissolve the tin plating layer on the PCB, and the open circuit replacement is needed. The retired tin solution not only contains a large amount of valuable metals, but also contains nitric acid with higher concentration and other organic components, and belongs to dangerous wastes. If the waste water is not effectively treated, a great amount of resources are wasted, and a huge potential environmental pollution risk is brought. The treatment method of the waste tin stripping water mainly comprises the following steps: precipitation, distillation, electrolysis, and the like.
In general, the existing tin stripping water of nitric acid or nitric acid-alkyl sulfonic acid system has two problems in the tin stripping process and the treatment of tin stripping waste liquid: (1) The tin stripping process mainly takes nitric acid to dissolve tin and copper, and has the problems of heavy pollution of NOx gas, large amount of sludge and residual acid and high cost; (2) The technology for treating tin-stripping water by precipitation, electrolysis and distillation has the serious problems of high reagent consumption, low metal recovery rate, large wastewater amount and the like.
To solve the above problems, the applicant"a method of stripping tin water based on a hydrochloric acid-tin salt system and a method of stripping tin from waste stripping tin water (application No. 201410011267.0)" has been developed to provide a non-nitric acid type of stripping tin water based on a hydrochloric acid-tin salt system, and a method of recovering tin from such waste stripping tin water after stripping tin and regenerating the stripping tin water at the same time, although small test results indicate that tin on a tin plated plate can be effectively stripped using the stripping tin water. However, the subsequent industrial practice of applying the method to tin stripping and tin recovery of the printed circuit board has serious problems of low tin stripping speed (more than 10 minutes), serious corrosion of a copper substrate of the PCB, tin whisker phenomenon during diaphragm electrodeposition to extract tin, low electrodeposition efficiency and the like. The reason is that compared with the existing nitric acid or nitric acid-alkyl sulfonic acid system tin stripping water, the hydrochloric acid-tin salt system tin stripping water has relatively weak oxidation performance, and has weaker dissolution performance and slower tin stripping speed on the PCB. However, when the tin stripping solution is used to strip more tin from PCB, the tin stripping time must be prolonged, however, cl in the tin stripping solution is removed due to the hydrochloric acid-tin salt system - The corrosion to the PCB board belongs to 'pitting', and a plurality of small holes distributed in a punctiform form are prone to being formed on the PCB board, so that the surface of the copper substrate after tin stripping is very uneven, and the subsequent electronic processing performance of the PCB is affected.
In order to effectively improve the tin stripping speed, the applicant has also developed a method for stripping tin by a two-stage method of a PCB (application number 201811126057.0) to provide a first stage of composite two-stage tin stripping water based on a hydrochloric acid-tin salt system and a second stage of composite two-stage tin stripping water based on a nitric acid-nitrate system, so that the discharge of ammonia nitrogen wastewater during the treatment of waste tin stripping water is effectively reduced while the tin is further recycled on line. However, the prominent environmental problems of NOx gas pollution, sludge, and residual acid, etc. are still not completely solved.
Disclosure of Invention
Aiming at the problems and the defects existing in the prior art, the invention aims to solve the technical problems that: the method provided by the invention can effectively shorten tin stripping time, improve tin stripping efficiency and simultaneously recover tin in the solution, and can also effectively avoid the emission of ammonia nitrogen wastewater during waste tin stripping water treatment. The purpose of cleaning and high-efficiency production of the PCB tin stripping is achieved.
The invention also aims to provide a device which is matched with the method for removing tin and recovering tin of the PCB in one step, is simple and practical and can comprehensively obtain better tin removing and tin recovering effects.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a method for removing tin and recovering tin in one step of PCB comprises the steps of carrying out electrolytic tin removal and tin recovery under the simultaneous action of an external field coupling strengthening condition and an electric field in an electrolytic reaction device for continuously removing tin from an etched circuit board through an acid system solution; along with the progress of the reaction, the tin plating layer on the circuit board is dissolved into the solution, and tin ions in the solution are deposited and separated out at the cathode.
The acidic system solution is a solution composed of single acid or mixed acid selected from sulfuric acid, methanesulfonic acid and hydrochloric acid, a tin stripping accelerator, a tin stripping corrosion inhibitor, an electrolytic stabilizer and a solution dispersing agent, and sulfuric acid or methanesulfonic acid is preferred.
The tin stripping accelerant is one of tetraethylammonium bromide, sodium methylsulfonate, tartaric acid, sodium citrate and sulfosalicylic acid; the tin stripping corrosion inhibitor is one of benzotriazole, methylbenzotriazole, sebacic acid or sodium benzoate; the electrolytic stabilizer is one of animal bone glue, cresol sulfonic acid, phenol sulfonic acid and beta-naphthol; the solution dispersing agent is one of ethylene oxide, polyethylene glycol and alkylphenol polyoxyethylene, the preferred tin stripping accelerant is sodium methylsulfonate, the preferred tin stripping corrosion inhibitor is benzotriazole, the preferred electrolytic stabilizer is animal bone glue, and the preferred solution dispersing agent is ethylene oxide.
The acidity of the acid system is 1 mol/L-5 mol/L; the concentration of the tin stripping accelerator is 0.1-5 g/L; the concentration of the tin stripping corrosion inhibitor is 0.01-2 g/L; the concentration of the electrolytic stabilizer is 0.05-20 g/L; the concentration of the solution dispersing agent is 0.01-5 g/L, the preferable acidity is 2-4 mol/L, the preferable concentration of the tin stripping accelerator is 0.5-3 mol/L, the preferable concentration of the tin stripping corrosion inhibitor is 0.5-1 mol/L, and the preferable concentration of the solution dispersing agent is 0.05-3 mol/L.
The external field coupling strengthening condition is ultrasonic coupling strengthening, the ultrasonic frequency is 20-500 kHz, the ultrasonic power is 10-200W, the preferable ultrasonic frequency is 40kHz, and the preferable ultrasonic power is 100W.
The electrolytic tin stripping electric field is a pulse electric field, the pulse frequency of the pulse electric field is 50-2000 Hz, the duty ratio is 50-90%, and the average current density of the initial electrolytic pulse is 10-500A/m 2 The preferred pulse frequency is 100-500 Hz, the preferred duty cycle is 70-80%, and the preferred average current density is 50-150A/m 2 。
The time of the etched circuit board passing through the continuous tin stripping electrolytic reaction device is 15-120 s, and the preferable reaction time is 45-90 s.
A device for removing tin and recovering tin of a PCB in one step comprises a tin removing groove, a liftable anode groove, an anode guide rod, a cathode guide rod, a graphite anode, a conveying device, an ultrasonic generator, a cathode plate and a pulse power supply; the bottom of the tin stripping tank is provided with a groove capable of placing a cathode and a solution inlet/outlet; one end of the anode guide rod is connected with the graphite anode, the other end of the anode guide rod is connected with the positive electrode of the pulse power supply through a lead, one end of the cathode guide rod is connected with the cathode plate, and the other end of the cathode guide rod is connected with the negative electrode of the pulse power supply through a lead.
The cathode guide rod and the anode guide rod of the device are made of stainless steel.
The device is characterized in that the cathode plate is made of stainless steel, titanium plate or refined copper.
Principle and advantages
According to the method and the device, the pulse electric field is introduced to replace the addition of the oxidant in the original tin stripping system, when the anode contacts with the PCB plating layer, a circuit is formed, oxidation reaction occurs on the surface of the plating layer to enable tin to enter the solution (as shown in formula 1) in a tin ion mode, reduction reaction occurs on the surface of the cathode to enable tin ions to be separated out from the cathode in a metal tin mode (as shown in formula 2), and more surprisingly, after the ultrasonic coupling external field is added, the energy brought by ultrasonic waves further accelerates the dissolution of the tin plating layer, concentration polarization in the solution is reduced, the distribution of tin ions in the solution is more uniform, and particularly the concentration polarization of each ion near the cathode sheet is remarkably reduced, so that tin can be deposited on the cathode sheet in a flatter mode. In addition, the pulse current adopted by the invention is used for dissolving the tin plating layer of the PCB, no oxidizing substance exists in the solution, and when the current and the voltage are controlled under specific conditions, the tin can be dissolved, the copper on the PCB can be prevented from being dissolved, the tin can be selectively dissolved, and the high-efficiency selective separation of the tin on the PCB is realized.
Sn-2e＝Sn 2+ (1)
Sn 2+ +2e＝Sn (2)
Compared with the existing nitric acid or nitric acid-alkyl sulfonic acid system, the method avoids using nitric acid as a solution and an oxidant, effectively avoids the environmental problems of heavy pollution of NOx gas, large amount of sludge and residual acid, high cost and the like, simultaneously greatly reduces the technical problems of large reagent consumption, low metal recovery rate and large wastewater amount in the tin stripping treatment process, and realizes one-step tin stripping and tin recovery. The invention has important significance for promoting the progress of PCB production technology, saving energy, reducing consumption and protecting environment in China.
Drawings
FIG. 1 is a schematic diagram of a one-step tin stripping and simultaneous tin recovery apparatus according to the present invention.
In the figure, the anode rod is 1-, the graphite anode is 2-, the anode tank is 3-and can be lifted, the PCB transmission device is 4-, the ultrasonic generator is 5-and the solution inlet/outlet is 6-and the cathode plate is 7-and the cathode rod is 8-and the tin stripping solution is 9-and the pulse power supply is 10-.
Detailed description of the preferred embodiments
The following examples are intended to further illustrate the invention without limiting it.
The invention relates to a device for removing tin and recovering tin in one step, which comprises a tin removing tank, a liftable anode tank, an anode guide rod, a cathode guide rod, a graphite anode, a conveying device, an ultrasonic generator, a cathode plate and a pulse power supply; the bottom of the tin stripping tank is provided with a groove capable of placing a cathode and a solution inlet/outlet; one end of the anode guide rod is connected with the graphite anode, the other end of the anode guide rod is connected with the positive electrode of the pulse power supply through a lead, one end of the cathode guide rod is connected with the cathode sheet, and the other end of the cathode guide rod is connected with the negative electrode of the pulse power supply through a lead; the cathode is made of titanium plate.
Example 1
A tin-plated PCB supplied by a company, the surface of which is tin plated at 30g per square meter.
Preparing sulfuric acid solution in a device for removing tin in one step and recovering tin at the same time, wherein the sulfuric acid acidity of the mixed solution is 1.5mol/L, the sodium methylsulfonate is 0.5g/L, the benzotriazole is 0.2g/L, the animal bone glue is 0.1g/L, the polyethylene glycol is 0.1g/L, the ultrasonic frequency is 100kHz, the ultrasonic frequency is 100W, the pulse frequency is 200Hz, the duty ratio is 70%, and the pulse average current density is 100A/m 2 And (3) carrying out reaction under the condition of (2) adjusting the speed of a conveyor belt to ensure that the tin removing time of the PCB in the solution is 60 seconds, thus obtaining the PCB with a flat and smooth surface, and observing the PCB by an optical microscope, wherein the surface of the obtained tin removing plate is free of tin plating, and the surface of the obtained tin removing plate is flat and smooth through a substrate. And analyzing the PCB after tin stripping by adopting a chemical analysis method, and finding that the tin content of the surface of the PCB after tin stripping is zero. After a continuous tin stripping test, the cathode obtains a tin simple substance with the current efficiency of 90.51 percent, and the cathode surface obtained after the cathode plate is taken out for observation is flat and smooth. The cathode was obtained by analysis using a chemical analysis method, and the tin content was found to be 99.99%.
Example 2
A tin-plated PCB supplied by a company, the surface of which is tin plated at 32g per square meter.
Preparing sulfuric acid solution in a device for removing tin in one step and recovering tin at the same time, wherein the acidity of the mixed solution is 2mol/L, the tartaric acid is 0.5g/L, the methylbenzotriazole is 0.2g/L, the cresol sulfonic acid is 10g/L, the ethylene oxide is 0.1g/L, the ultrasonic frequency is 200kHz, the ultrasonic frequency is 200W, the pulse frequency is 500Hz, the duty ratio is 75%, and the pulse average current density is 50A/m 2 And (3) carrying out reaction under the condition of (2) adjusting the speed of a conveyor belt to ensure that the tin removing time of the PCB in the solution is 40 seconds, thus obtaining the PCB with a flat and smooth surface, and observing the PCB by an optical microscope, wherein the surface of the obtained tin removing plate is free of tin plating, and the surface of the obtained tin removing plate is flat and smooth through a substrate. And analyzing the PCB after tin stripping by adopting a chemical analysis method, and finding that the tin content of the surface of the PCB after tin stripping is zero. After a continuous tin stripping test, the cathode obtains a tin simple substance with the current efficiency of 91.02 percent, and the cathode surface obtained after the cathode plate is taken out for observation is flat and smooth. By chemical separationThe cathode was obtained by analysis by an analytical method, and the tin content was found to be 99.98%.
Example 3
A tin-plated PCB provided by a company, the surface of which is tin plated 31g per square meter.
Preparing sulfuric acid solution in a device for removing tin in one step and recovering tin at the same time, wherein the acidity of the mixed solution is 5mol/L, the acidity of sulfosalicylic acid is 0.1g/L, the sodium benzoate is 0.01g/L, the beta-naphthol is 0.05g/L, the alkylphenol ethoxylate is 0.01g/L, the ultrasonic frequency is 20kHz, the ultrasonic frequency is 10W, the pulse frequency is 50Hz, the duty ratio is 50%, and the pulse average current density is 50A/m 2 And (3) carrying out reaction under the condition of (3) adjusting the speed of a conveyor belt to ensure that the tin removing time of the PCB in the solution is 120 seconds, thus obtaining the PCB with a flat and smooth surface, and observing the PCB by an optical microscope, wherein the surface of the obtained tin removing plate is free of tin plating, and the surface of the obtained tin removing plate is flat and smooth through a substrate. And analyzing the PCB after tin stripping by adopting a chemical analysis method, and finding that the tin content of the surface of the PCB after tin stripping is zero. After a continuous tin stripping test, the cathode obtains tin simple substance with current efficiency of 84.45%, and the cathode surface obtained after the cathode plate is taken out and observed is flat and smooth. The cathode was obtained by analysis using a chemical analysis method, and the tin content was found to be 99.95%.
Comparative example 1 (solder stripping under non-inventive parameters of the configuration)
The solution as described in example 1 was configured, except that no tin stripping accelerator, tin stripping corrosion inhibitor, electrolytic stabilizer, and solution dispersant were added, and the reaction was performed at ultrasonic frequency, ultrasonic power, pulse frequency, duty cycle, and pulse average current density as described in example 1 for a tin stripping time of 120s, and it was found that the tin plating on the PCB was difficult to completely strip, and 19.14% of the tin remained on the PCB after analysis. The cathode is free from the generation of substances with specific morphology.
Comparative example 2 (without applied ultrasonic external field coupling enhancement)
The solution as described in example 2 was configured, except that no ultrasonic external field coupling enhancement was applied, the reaction was performed at the pulse frequency, duty cycle, and pulse average current density as described in example 2, the tin stripping time was 120s, the tin plating on the PCB was found to be difficult to completely strip, and 8% of the tin remained on the PCB after analysis. The tin on the surface of the cathode grows a large amount of 'whiskers', the cathode gas is seriously separated out, and the current efficiency is only 42.18%. Comparative example 3 (without pulsed electric field)
The solution as described in example 2 was configured, except that no ultrasonic external field coupling enhancement was applied, the reaction was performed at the ultrasonic frequency and ultrasonic power as described in example 2, the tin stripping time was 120s, the tin plating on the PCB was found to be difficult to completely strip, and 64% of the tin remained on the PCB after analysis. The cathode had no product formation.
Claims (7)
1. A method and a device for withdrawing tin and recovering tin of a PCB in one step are characterized in that: in the continuous tin stripping electrolytic reaction device for the etched circuit board through the acid system solution, electrolytic tin stripping and tin recovery are carried out under the simultaneous actions of an external field coupling strengthening condition and an electric field; along with the progress of the reaction, the tin plating layer on the circuit board is dissolved into the solution, and tin ions in the solution are deposited and separated out at the cathode.
2. The method according to claim 1, characterized in that: the acidic system solution is a solution composed of single acid or mixed acid selected from sulfuric acid, methanesulfonic acid and hydrochloric acid, a tin stripping accelerator, a tin stripping corrosion inhibitor, an electrolytic stabilizer and a solution dispersing agent.
3. Acidic system solution according to claims 1 and 2, characterized in that: the tin stripping accelerant is one of tetraethylammonium bromide, sodium methylsulfonate, tartaric acid, sodium citrate and sulfosalicylic acid; the tin stripping corrosion inhibitor is one of benzotriazole, methylbenzotriazole, sebacic acid or sodium benzoate; the electrolytic stabilizer is one of animal bone glue, cresol sulfonic acid, phenol sulfonic acid and beta-naphthol;
the solution dispersing agent is one of ethylene oxide, polyethylene glycol and alkylphenol polyoxyethylene.
4. An acidic system solution according to claims 1-3, characterized in that: the acidity of the acid system is 1 mol/L-5 mol/L; the concentration of the tin stripping accelerator is 0.1-5 g/L; the concentration of the tin stripping corrosion inhibitor is 0.01-2 g/L; the concentration of the electrolytic stabilizer is 0.05-20 g/L; the concentration of the solution dispersing agent is 0.01-5 g/L.
5. The method according to claim 1, characterized in that: the external field coupling strengthening condition is ultrasonic coupling strengthening, the ultrasonic frequency is 20-500 kHz, and the ultrasonic power is 10-200W.
6. The method according to claim 1, characterized in that: the electrolytic tin stripping electric field is a pulse electric field, the pulse frequency of the pulse electric field is 50-2000 Hz, the duty ratio is 50-90%, and the average current density of the initial electrolytic pulse is 10-500A/m 2 。
7. The method according to claim 1, characterized in that: the time for the etched circuit board to pass through the continuous tin stripping electrolytic reaction device is 15-120 s.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310474416.6A CN116446029A (en) | 2023-04-28 | 2023-04-28 | Method and device for withdrawing tin and recovering tin simultaneously for PCB (printed circuit board) in one step |
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|---|---|---|---|
| CN202310474416.6A CN116446029A (en) | 2023-04-28 | 2023-04-28 | Method and device for withdrawing tin and recovering tin simultaneously for PCB (printed circuit board) in one step |
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