Non-toxic sodium cyanide or potassium cyanide zinc-plating electroplating solution and preparation method therefor

Description

Non-poisonous sodium cyanide or potassium cyanide zinc plating solution and preparation method thereof TECHNICAL FIELD

[0001] The present application relates to a non-poisonous sodium cyanide or potassium cyanide zinc plating solution and preparation method thereof, and belongs to the technical field of plating solution and preparation thereof. BACKGROUND

[0002] The complexing agent is a compound capable of forming a complex ion with a metal ion. In an electroplating solution, except for a few electroplating solutions such as acid solution plating iron, plating nickel, plating chromium, and plating copper, which do not use or do not need to use a complexing agent, most electroplating solutions such as alkaline solution plating silver, plating gold, plating copper, plating zinc, plating tin, and plating copper-tin alloy need to use a complexing agent.

[0003] A commonly used complexing agent such as cyanide is widely used in the electroplating industry because the cyanide ion has excellent complexing ability, and cyanide electroplating is the best electroplating method. However, NaCN, KCN, CuCN, and the like used in cyanide electroplating are highly toxic compounds, and the lethal dose thereof for a human being is only 0.005 g. The cyanide not only harms the health of an operator but also pollutes the environment, and the treatment of wastewater is difficult, and the treatment cost thereof is extremely high. Therefore, in order to protect the environment and reduce public hazards, it is urgent to develop a complexing agent for replacing cyanide for use in a cyanide-free electroplating process.

[0004] Publication No. CN103755738B, published on June 1, 2016, discloses a complexing agent, a preparation method and use thereof. The complexing agent is applied to the production of an electroplating solution, is convenient to process, has strong complexing ability to metals, and has a complexing constant of 10 26～27 for copper ions, which is much better than that of a cyanide-free complexing agent in the prior art. The electroplating solution prepared from the complexing agent has stable quality, good dispersibility, a wide range of process current density, and a wide application range. With higher requirements for the quality of electroplated products, after meeting the higher complexing force, the deep plating ability of the complexing agent also needs to be considered, the plating layer needs to be more compact, and the electroplating efficiency needs to be improved to achieve energy saving of the electroplating process. Based on the problems to be solved in the newly proposed cyanide-free electroplating, the present inventors have developed a new non-poisonous sodium cyanide or potassium cyanide zinc plating solution and disclosed a preparation method thereof. SUMMARY

[0005] One of the purposes of the present application is to solve the defects of the prior art and provide a new non-poisonous sodium cyanide or potassium cyanide zinc plating solution. The electroplating solution has strong deep plating ability, the plating layer is more delicate and compact, the electroplating efficiency is high, and energy saving of the electroplating process can be achieved.

[0006] The second purpose of the present application is to provide a preparation method of the new non-poisonous sodium cyanide or potassium cyanide zinc plating solution. The method is easy to realize industrial production, and the quality of the electroplating solution product is stable.

[0007] The technical scheme adopted by the present application to solve its technical problems is:

[0008] A non-poisonous sodium cyanide or potassium cyanide zinc plating solution, comprising a complexing agent, a complexing agent zinc salt and water,

[0009] The general formula of the complexing agent zinc salt in the non-cyanide zinc plating solution is Zn n [C 4n N 4n+2 S 2n O 2n H 2n+6 , and its structural formula is as follows:

[0010] Wherein, n is 1, 2, 3, …, 50.

[0011] Preferably, the general formula of the complexing agent in the non-poisonous sodium cyanide or potassium cyanide zinc plating solution is R m [C 2m N 2m+1 S m O m H m+3 , and its structural formula is as follows:

[0012] Wherein, R is K or Na, and m is 1, 2, 3, …, 50.

[0013] The foregoing technical scheme is explained below with several examples:

[0014] A: When R is K and m is 1, the general formula of the complexing agent is K[C2N3SOH4], and its structural formula is as follows:

[0015] The structural formula of the complexing agent zinc salt obtained by processing this kind of complexing agent is: (1 / 2)Cu[C2N3SOH4], n=m, that is: Zn[C4N6S2O2H8], and its structural formula is as follows:

[0016] B: When R is K and n is 20, the general formula of the complexing agent is K 20 [C 40 N 41 S 20 O 20 H 23 , and its structural formula is as follows:

[0017] The structural formula of the complexing agent zinc salt obtained by processing this kind of complexing agent is as follows:

[0018] C: when R is Na, n is 50, the complexing agent is Na 50 [C 100 N 101 S 50 O 50 H 53 ] with the following structure:

[0019] The complexing agent zinc salt processed from the complexing agent has the following structure:

[0020] Preferably, R is K, n is 1, 2, or 3, and the structures are as follows, respectively:

[0021] Preferably, in the non-toxic cyanide sodium or potassium zinc plating solution, the mass fraction of the complexing agent is 15-25%, the mass fraction of the complexing agent zinc salt is 2.5-3.5%, and the rest is water.

[0022] More preferably, in the non-toxic cyanide sodium or potassium zinc plating solution, the mass fraction of the complexing agent is 20%, the mass fraction of the complexing agent zinc salt is 3.0%, and the rest is water.

[0023] In the non-toxic cyanide sodium or potassium zinc plating solution of the present application, at least the complexing agent zinc salt is prepared by reacting the complexing agent of the present application with a soluble zinc salt, and the complexing agent in the further mixed preparation of the plating solution can be selected from conventional complexing agents, the complexing agent of the present application, or preferably the complexing agent of the present application.

[0024] The value of n in the complexing agent zinc salt is the same as the value of m in the complexing agent, or can be different. For example, the complexing agent in the aforementioned A is mixed with the complexing agent zinc salt in the aforementioned A, or is mixed with the complexing agent zinc salt in the aforementioned B, and all can be processed into the non-toxic cyanide sodium or potassium zinc plating solution of the present application.

[0025] Preferably, the complexing agent is prepared from yellow prussiate, sodium or potassium thiosulfate (when R is K, potassium thiosulfate is used, and when R is Na, sodium thiosulfate is used) and urea as raw materials, in an oxygen-containing atmosphere, with rhodium and / or platinum as catalyst, through solid-state polymineral salt reaction, dissolution in water, separation, concentration of the separation liquid, and drying.

[0026] The reaction formula of the preparation method of the complexing agent of the present application is as follows: (n / 4)[K4Fe(CN)6]+nNa2S2O3+nCH4N2O+20 / nO2=K n [C 2n N 2n+1 S n O n H n+3+(n / 4)N2+nNa2SO3+(n-1)NH3,

[0027] or; (n / 4)[K4Fe(CN)6]+nK2S2O3+nCH4N2O+20 / nO2=K n [C 2n N 2n+1 S n O n H n+3 +(n / 12)Fe3C+(5n / 12)C+(n / 4)N2+nK2SO3+(n-1)NH3;

[0028] The application also discloses a preparation method of the complexing agent, which comprises the following steps:

[0029] The yellow prussiate, sodium or potassium thiosulfate and urea are put into a rotary reaction kiln, a catalyst rhodium and / or platinum is added, and the reaction is carried out at 450-650℃ for 5-7 hours; the polymerized polymineral salt is dissolved in water, and then separated to remove insoluble substances to obtain a separated liquid; and the separated liquid is dried to obtain the finished complexing agent.

[0030] Preferably, the separation is carried out by any one or more of suction filtration, plate-frame pressure filtration and centrifugal separation.

[0031] Preferably, the separated liquid is concentrated before drying, and the separated liquid is concentrated to a water content of 30-40%; and the concentrated material is dried to a water content of less than 5%; and the concentration is carried out by vacuum concentration.

[0032] Preferably, the drying is carried out by spray drying, and the inlet air temperature of the spray drying is 100-200℃.

[0033] Preferably, the preparation method of the complexing agent zinc salt comprises the following steps: water is added into a reactor, then a molar amount of the complexing agent and a water-soluble copper zinc are added, and the reaction is carried out by stirring; and after the reaction is completed, the precipitate obtained by filtration is rinsed and dried to obtain the complexing agent copper salt.

[0034] The preparation method of the cyanide-free alkali zinc plating solution of the application comprises the following steps: the complexing agent zinc salt, the complexing agent and water are mixed according to a proportioning, and then dissolved by stirring; and the pH value is adjusted to 10-12 to obtain the cyanide-free alkali zinc plating solution.

[0035] The application has the following beneficial effects:

[0036] The preparation raw material of the complexing agent is widely sourced, low in price, simple in preparation process, transportation, storage and use, and low in production cost; the complexing agent is applied to the production of electroplating liquid, convenient to process, and the prepared electroplating liquid has strong complexing capacity for metals, for example, the complexing constant of the complexing agent for copper ions can reach 10 26-27 (Comparing with the cyanide-free complexing agent in the prior art), far superior to the conventional complexing agent (mainly potassium pyrophosphate, citric acid and HEDP) in the prior art, the alkaline zinc plating electroplating liquid prepared from the complexing agent has stable quality, good dispersibility, a wide range of process current density, and a wide application range of the electroplating liquid (such properties are comparable to the electroplating liquid prepared from the cyanide-free complexing agent in the prior art), in addition, the complexing agent has strong plating capacity, the plating layer is more delicate and dense, the electroplating efficiency is high, and energy saving of the zinc alloy electroplating process can be achieved. DETAILED DESCRIPTION

[0037] The technical solutions of the present application are further described below through specific examples. The reagents, raw materials and devices and facilities used in the following examples are all commercially available conventional reagents, raw materials, devices and facilities.

[0038] Example 1

[0039] A complexing agent, the structural formula of which is as follows:

[0040] The polymeric inorganic salt reaction formula of the complexing agent is as follows:

[0041] (1 / 4)[K4Fe(CN)6]+K2S2O3+CH4N2O+20O2=K[C2N3SOH4]+(1 / 12)Fe3C+(5 / 12)C+(1 / 4)N2+K2SO3; the preparation method steps are as follows:

[0042] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary kiln, a catalyst rhodium and / or platinum is added, the reaction is carried out at 450-460℃ for 7 hours, the polymeric inorganic salt is dissolved in water, the insoluble substances are removed through separation, the separation liquid is obtained, and the complexing agent is obtained through drying of the separation liquid.

[0043] In Example 1, the separation is carried out by suction filtration, the separation liquid is concentrated before drying, the separation liquid is concentrated to a water content of 30%, the concentrated material is dried to a water content of less than 5%, the concentration is carried out by vacuum concentration, and the drying is carried out by spray drying, and the inlet air temperature of the spray drying is 100-110℃.

[0044] Example 2

[0045] A complexing agent, the structural formula of which is as follows:

[0046] The polymineral salt reaction formula of the complexing agent is as follows:

[0047] (1 / 2)[K4Fe(CN)6]+2K2S2O3+2CH4N2O+10O2=K2[C4N5S2O2H5]+(1 / 6)Fe3C+(5 / 6)C+(1 / 2)N2+2K2SO3+NH3; the preparation method steps are as follows:

[0048] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary reaction kiln, a catalyst rhodium and / or platinum is added, and the reaction is carried out at 640-650°C for 5 hours. The polymerized polymineral salt is dissolved in water, separated, and the insoluble substances are removed to obtain a separated liquid. The separated liquid is dried to obtain the finished complexing agent.

[0049] In Example 1, the separation is carried out by plate-frame pressure filtration, and the separated liquid is concentrated before drying. The separated liquid is concentrated to a water content of 40%, and the concentrated material is dried to a water content of less than 5%. The concentration is carried out by vacuum concentration, and the drying is carried out by spray drying. The inlet air temperature of the spray drying is 190-200°C.

[0050] Example 3

[0051] A complexing agent, the structural formula of which is as follows:

[0052] The polymineral salt reaction formula of the complexing agent is as follows: (3 / 4)[K4Fe(CN)6]+3K2S2O3+3CH4N2O+20 / 3O2=K3[C6N7S3O3H6]+(1 / 4)Fe3C+(5 / 4)C+(3 / 4)N2+3K2SO3+2NH3; the preparation method steps are as follows:

[0053] The yellow prussiate, sodium or potassium thiosulfate and urea are placed in a rotary reaction kiln, a catalyst rhodium and / or platinum is added, and the reaction is carried out at 580-590°C for 6 hours. The polymerized polymineral salt is dissolved in water, separated, and the insoluble substances are removed to obtain a separated liquid. The separated liquid is dried to obtain the finished complexing agent.

[0054] In Example 3, the separation is carried out by centrifugal separation, and the separated liquid is concentrated before drying. The separated liquid is concentrated to a water content of 35%, and the concentrated material is dried to a water content of less than 5%. The concentration is carried out by vacuum concentration, and the drying is carried out by spray drying. The inlet air temperature of the spray drying is 160-170°C.

[0055] Example 4

[0056] A complexing agent, the structural formula and preparation method of which are the same as those of Example 3, except that n=50.

[0057] Example 5

[0058] A complexing agent, the structural formula of the complexing agent is the same as that of Example 1, except that Na is used instead of K.

[0059] Example 6

[0060] A complexing agent, the structural formula of the complexing agent is the same as that of Example 2, except that Na is used instead of K.

[0061] Example 7

[0062] A complexing agent, the structural formula of the complexing agent is the same as that of Example 3, except that Na is used instead of K.

[0063] Example 8

[0064] A complexing agent, the structural formula of the complexing agent is the same as that of Example 4, except that Na is used instead of K.

[0065] The complexing agent of Examples 1-8 of the present application is used for electroplating, and the electroplating solution for pre-plating zinc is taken as an example. The amount of the complexing agent in the electroplating solution is 1-40%, preferably 20%. The application of the complexing agent of the present application is illustrated by taking the amount of 20% as an example.

[0066] The reaction formula for preparing the complexing agent zinc salt from the complexing agent is as follows, taking n as 1 as an example:

[0067] ZnSO4+2K[C2N3SOH4]=K2SO4+Zn[C2N3SOH4]2. The reaction condition is normal temperature and pressure.

[0068] Example 9: The complexing agent of Example 1 is used in the electroplating solution for pre-plating zinc

[0069] Water is added to a reaction kettle, the complexing agent of Example 1 is added according to the molar ratio, and a molar amount of zinc salt is added for reaction. After the reaction is completed, the precipitate is filtered, the precipitate is rinsed and dried to obtain the complexing agent zinc salt;

[0070] The electroplating solution is prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest of water, and adjusting the pH to 10.0 with sodium hydroxide.

[0071] Example 10: The complexing agent of Example 2 is used in the electroplating solution for pre-plating copper

[0072] Water is added to a reaction kettle, the complexing agent of Example 2 is added according to the molar ratio, and a molar amount of zinc salt is added for reaction. After the reaction is completed, the precipitate is filtered, the precipitate is rinsed and dried to obtain the complexing agent zinc salt;

[0073] The plating solution was prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest water, and adjusting the pH to 12.0 with sodium hydroxide.

[0074] Example 11: The complexing agent of Example 3 was used in a pre-plating copper plating solution

[0075] The reaction kettle was charged with water, and the complexing agent of Example 3 was added in a molar ratio. A molar amount of zinc salt was added for reaction. After the reaction was completed, the precipitate was filtered, rinsed, and dried to obtain the complexing agent zinc salt.

[0076] The plating solution was prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest water, and adjusting the pH to 11.0 with sodium hydroxide.

[0077] Examples 12-16: The complexing agents of Examples 4-8 were used respectively in a pre-plating zinc plating solution

[0078] The reaction kettle was charged with water, and the complexing agent of Example 4-8 was added in a molar ratio. A molar amount of zinc salt was added for reaction. After the reaction was completed, the precipitate was filtered, rinsed, and dried to obtain the complexing agent zinc salt.

[0079] The plating solution was prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest water, and adjusting the pH to 11.5 with sodium hydroxide.

[0080] Comparative Example 17: Potassium pyrophosphate complexing agent

[0081] The plating solution was prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest water, and adjusting the pH to 11.5 with sodium hydroxide.

[0082] Comparative Example 18: The complexing agent of Patent No. 2014100151872

[0083] The plating solution was prepared by mixing 20% of the complexing agent, 3% of the complexing agent zinc salt, and the rest water, and adjusting the pH to 11.5 with sodium hydroxide.

[0084] Performance test:

[0085] The above Examples 9-16, Comparative Examples 17-18 were tested for performance according to the following method.

[0086] The cyanide-free zinc plating solutions prepared from Examples 9-16 and Comparative Examples 17-18 were subjected to the following studies:

[0087] 1. Hull cell test (267 ml)

[0088] 1.1 Preliminary test: The cyanide-free zinc plating solutions prepared in Examples 9-16 and Comparative Examples 17-18 were sheeted under the conditions of temperature 25°C, circuit 1A (constant current), air agitation, time 5 min. During sheeting of the plating solutions of Examples 9-16, it was observed that the bath voltage was also relatively stable under constant current conditions and the plated sheets exhibited the characteristics of half-spot, fine crystals on a large area. Examples 9-16 were all superior to Comparative Example 18, and Comparative Example 18 was superior to Comparative Example 17.

[0089] 1.2 Hull cell test to determine the current density range:

[0090] The cyanide-free zinc plating solutions prepared in Examples 9-16 and Comparative Examples 17-18 were sheeted by Hull to determine the optimum current density range under the conditions of temperature 55°C, current 1A, time 10 min. The sheet material used for sheeting was A3 steel sheet of 0.5*70*100, polished with 600# water sandpaper. The current density at each point of the test sheet was calculated according to the empirical formula Jk = I (5.1-5.24LgL). Through sheeting and current density calculation, it was found that the current density range of the plating solutions prepared in Examples 9-16 was 0.5 A / dm 2 to 5 A / dm 2 .

[0091] 2 Test of plating solution and plating performance

[0092] 2.1 Measurement of current efficiency: The current efficiency of the plating solutions prepared in Examples 9-16 was measured by copper coulomb meter, and the average current efficiency was 93.2%. The current efficiency of the plating solution prepared in Example 17 was 87.2%, and the current efficiency of the plating solution prepared in Example 18 was 89.8%.

[0093] 2.2 Measurement of throwing power of plating solution

[0094] The throwing power of the plating solution was measured by the bending cathode method under the conditions of current 1A, no oil air agitation, temperature 55°C, time 30 min, and the test material was A3 copper sheet of 0.5*70*100, polished with 600# water sandpaper.

[0095] The average throwing power of the plating solutions prepared in Examples 9-16 was 93.2%, the throwing power of the plating solution prepared in Example 17 was 87.1%, and the throwing power of the plating solution prepared in Example 18 was 90.3%.

[0096] 2.3 Measurement of covering power

[0097] The covering power of the plating solution was measured by the inner hole method, the size of the copper pipe was 10 mm*100 mm, the through hole and blind hole method was used, the temperature of the plating solution was 55°C, and the cathode current density was 0.5 A / dm 2, time 5 min. After the experiment, the iron pipe was dissected to observe the plated layer inside the pipe.

[0098] The cyanide-free zinc plating electrolyte prepared in Examples 9-16 and Comparative Examples 17-18 was used as the experimental electrolyte. After the experiment, it was found that the through holes and blind holes were all plated with zinc alloy layer, indicating that the covering capacity of the electrolyte prepared in Examples 9-16 was excellent, superior to that of Example 18, and more superior to that of Example 17.

[0099] 2.4 Bonding force test

[0100] 2.4.1 Bending experiment: polished iron sheet (A3) with a thickness of 0.5 mm was used, the temperature of the electrolyte was 55°C, the cathode current density was 2 A / dm 2 , time 15 min.

[0101] The cyanide-free zinc plating electrolyte prepared in Examples 9-16 and Comparative Examples 17-18 was used as the experimental electrolyte. After the experiment, the plated test piece was repeatedly bent until it broke, and there was no peeling phenomenon at the crack, proving that the plated layer and the substrate were not separated.

[0102] 2.4.2 Thermal shock experiment: polished iron sheet (A3) with a thickness of 0.5 mm was used, the temperature of the electrolyte was 55°C, the cathode current density was 2 A / dm 2 , time 15 min.

[0103] The cyanide-free zinc plating electrolyte prepared in Examples 9-16 and Comparative Examples 17-18 was used as the experimental electrolyte. After the experiment, the plated test piece was placed in an oven and baked to 200°C for 1 h, and then immediately immersed in 0°C water for quenching. No blistering and peeling phenomenon of the plated layer was found.

[0104] 2.5 Plated layer toughness experiment: A3 steel sheet with a thickness of 1 mm was passivated with chromium acid, and then directly hung in the electrolyte of Examples 9-16 and Comparative Examples 17-18. After the thickness of the plated layer reached 20 μm, the plated layer was peeled off, bent at 180°C, and squeezed at the bending part. The plated layer did not break, indicating that the plated layer had good toughness. Among them, Examples 9-16 were superior to Example 18, and more superior to Example 17.

[0105] 2.6 Plated layer porosity experiment: polished iron sheet (A3) with a thickness of 0.5 mm was used, the temperature of the electrolyte was 55°C, the cathode current density was 1 A / dm 2 , time 20 min, and the porosity experiment was carried out by the filter paper test method using potassium ferricyanide solution.

[0106] Potassium ferricyanide 10 g / L; sodium chloride 20 g / L.

[0107] The experimental results showed that the porosity of the plated layer formed by the electrolyte prepared in Examples 9-16 as the experimental object was all ≤0.58 pieces / dm2 , better than 1.5 A / dm of Example 18 2 , better than 3 A / dm of Example 17 2 .

[0108] 2.7 Measurement of deposition rate: set current 1 A, temperature 55°C, time 30 min, the results show that the deposition rate of the plating solution prepared in Examples 9-16 is 0.74 μm / min, the deposition rate of the plating solution prepared in Example 17 is 0.51 μm / min, and the deposition rate of the plating solution prepared in Example 18 is 0.60 μm / min.

[0109] The plating solutions prepared in Examples 9-16 were further subjected to pilot experiments, and the pilot process parameters are as follows:

[0110] Process flow: steel workpiece → ultrasonic oil removal → water washing 1 → water washing 2 → anode electrolytic oil removal → water washing 1 → water washing 2 → acid pickling oil removal → water washing 1 → water washing 2 → hydrochloric acid washing → water washing 1 → water washing 2 → terminal electrolytic oil removal → water washing 1 → water washing 2 → acid activation → water washing 1 → water washing 2 → the plating solution of Examples 9-16 → recovery → water washing 1 → water washing 2 → acid activation → acid copper, and then further electroplating treatment as required.

[0111] Ultrasonic oil removal: oil removal powder concentration 50±5 g / L, temperature 70±5°C, current density 1-5 A / dm 2 , time 5 min.

[0112] Cathode electrolytic oil removal: electrolytic oil removal powder concentration 50±5 g / L, temperature 70±5°C, current density 1-5 A / dm 2 , time 5-7 min.

[0113] Anode electrolytic oil removal: electrolytic oil removal powder concentration 50±5 g / L, temperature 70±5°C, current density 1-5 A / dm 2 , time 3-5 min.

[0114] Pickling: industrial hydrochloric acid concentration 15-20%, time 8-10 min, room temperature.

[0115] Activation: industrial hydrochloric acid concentration 5-10%, time 3-5 min, room temperature.

[0116] The plating solution of Examples 9-16: Baume degree 32-36, pH value 8.0, temperature 50-55°C, current density 0.5-5 A / dm 2 , time 5 min to several hours, and it has been proved that the flatness and brightness are still very good when plated to 100 μm. It is better than Comparative Example 18, and better than Comparative Example 17.

[0117] The plating solution prepared in Examples 9-16 was verified to have reliability and stable performance by continuously running a 50 L pilot plating production line for 20 months and a 350 L pilot plating production line for 11 months. The consumption of the plating solution was 10-50 ml / KAH. Based on the above pilot experiments, the process conditions for industrial production of the plating solution prepared in Examples 9-16 were obtained.

[0118] 1. Steel workpiece:

[0119] Process flow: Steel workpiece → ultrasonic oil removal → water washing 1 → water washing 2 → anode electrolytic oil removal → water washing 1 → water washing 2 → acid pickling oil removal → water washing 1 → water washing 2 → hydrochloric acid washing → water washing 1 → water washing 2 → terminal electrolytic oil removal → water washing 1 → water washing 2 → acid activation → water washing 1 → water washing 2 → pre- immersion → the plating solution of Examples 9-16 → recovery → water washing 1 → water washing 2 → acid activation → acid copper, and then further electroplating treatment as needed.

[0120] Process conditions:

[0121] Density of plating solution: 32-36 Baume

[0122] Temperature: 45-60°C

[0123] pH: 11-13

[0124] Agitation: air agitation plus cathode movement

[0125] Anode: electrolytic copper or oxygen-free electrolytic copper

[0126] Anode / cathode area ratio: 1:1.5-2.

[0127] Current: 0.5-2.5 A / dm 2

[0128] 2. Zinc alloy workpiece:

[0129] Process flow: Zinc alloy workpiece → hot dipping wax removal → ultrasonic wax removal → water washing 1 → water washing 2 → ultrasonic oil removal → water washing 1 → water washing 2 → anode electrolytic oil removal → water washing 1 → water washing 2 → acid salt activation → water washing 1 → water washing 2 → ultrasonic pre- immersion liquid pre- immersion for 30 s → the plating solution of Examples 9-16 (charged into the tank at 25-35°C) → recovery → water washing 1 → water washing 2 → acid activation → acid copper, and then further electroplating treatment as needed.

[0130] Process conditions:

[0131] Density of plating solution: 32-38 Baume

[0132] Temperature: 25-35°C

[0133] pH: 11-13

[0134] Agitation: air agitation with cathode movement

[0135] Anode: electrolytic copper or oxygen free electrolytic copper

[0136] Anode to cathode area ratio: 1:1.5-2.

[0137] Current: 0.5-1.5 A / dm 2 .

[0138] The above described embodiments are only a preferred solution of the present application, and do not limit the present application in any form, and other variations and modifications are possible without departing from the technical solution recited in the claims.

Claims

1. A non-virulent sodium or potassium cyanide zinc plating electroplating solution, characterized in that: The general formula of the complexing agent zinc salt in the non-acute cyanide sodium or potassium cyanide zinc plating solution comprising the complexing agent, the complexing agent zinc salt and water is Zn n [C 2n N 2n+1 S n O n H n+3 ]2, the structural formula is as follows: Wherein, n is 1, 2, 3, 50.

2. The non-poisonous sodium or potassium cyanide zinc plating solution according to claim 1, characterized in that: The general formula of the complexing agent in the non-poisonous sodium cyanide or potassium cyanide galvanization plating solution is R m [C 2m N 2m+1 S m O m H m+3 ] and its structural formula is as follows: Wherein, R is K or Na, m is 1, 2, 3, 50.

3. The non-virulent sodium or potassium cyanide galvanic zinc plating solution according to claim 1 or 2, characterized in that: The mass fraction of the complexing agent in the non-toxic cyanide sodium or potassium zinc plating solution is 15-25%, the mass fraction of the complexing agent zinc salt is 2.5-3.5%, and the rest is water.

4. The non-virulent sodium or potassium cyanide galvanization electroplating solution according to claim 3, characterized in that: The mass fraction of the complexing agent in the non-toxic cyanide sodium or potassium zinc plating solution is 20%, the mass fraction of the complexing agent zinc salt is 3.0%, and the rest is water.

5. The non-virulent sodium or potassium cyanide galvanic zinc plating solution according to claim 1 or 2, characterized in that: The preparation method of the complexing agent zinc salt is as follows: a reactor is added with water, then a molar amount of the complexing agent and a water-soluble zinc salt, and stirring is performed for reaction, after which the precipitate obtained by filtration is rinsed, dried, and the complexing agent zinc salt is obtained.

6. The non-virulent sodium or potassium cyanide galvanization electroplating solution according to claim 2, wherein, The preparation method of the complexing agent is as follows: hematin, sodium or potassium thiosulfate and urea are used as raw materials, rhodium and / or platinum is used as a catalyst in an oxygen-containing atmosphere, and after solid-state polymineral salt reaction, the complexing agent is obtained by dissolving in water, separation, concentration of the separation liquid, and drying.

7. The non-violent cyanide sodium or potassium zinc plating solution of claim 6, characterized by: The preparation method of the complexing agent is as follows: Hematin, sodium or potassium thiosulfate and urea are placed in a rotary kiln, the catalyst rhodium and / or platinum is added, and the reaction is carried out at 450-650 DEG C for 5-7 hours, the polymineral salt is dissolved in water, the insoluble substances are removed by separation, the separation liquid is obtained, and the complexing agent is obtained by drying the separation liquid.

8. The non-virulent sodium or potassium cyanide galvanic plating solution according to claim 6 or 7, characterized in that: The separation is any one or several of suction filtration, plate-frame pressure filtration and centrifugal separation.

9. The method of preparing a non-virulently sodium cyanide or potassium cyanide zinc electroplating solution according to claim 6 or 7, characterized in that: The separation liquid is concentrated before drying, the separation liquid is concentrated to a water content of 30-40%, the concentrated material is dried to a water content of less than 5%, the concentration is vacuum concentration, and the drying is spray drying with an air inlet temperature of 100-200 DEG C.

10. A process for the preparation of a non-vigorous cyanide sodium or potassium zinc plating bath according to any one of claims 1 to 9, characterized in that: The complexing agent zinc salt, the complexing agent and water are mixed according to the proportion, stirred and dissolved, and then the pH value is adjusted to 10.0-1 to obtain the non-toxic cyanide sodium or potassium zinc plating solution.

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