CN112981408A - Lead removing agent and surface lead removing process of lead brass component - Google Patents

Lead removing agent and surface lead removing process of lead brass component Download PDF

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Publication number
CN112981408A
CN112981408A CN202110158713.0A CN202110158713A CN112981408A CN 112981408 A CN112981408 A CN 112981408A CN 202110158713 A CN202110158713 A CN 202110158713A CN 112981408 A CN112981408 A CN 112981408A
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lead
parts
brass
acid
optionally
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林孝发
林孝山
汪火良
周年润
赖荣火
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Jomoo Kitchen and Bath Co Ltd
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Jomoo Kitchen and Bath Co Ltd
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    • 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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/44—Compositions for etching metallic material from a metallic material substrate of different composition
    • 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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/14—Aqueous compositions
    • C23F1/16—Acidic compositions
    • C23F1/18—Acidic compositions for etching copper or alloys thereof

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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

The application provides a lead removing agent and a surface layer lead removing process of a lead brass component, wherein the lead removing agent comprises the following components in parts by weight: 60 to 80 parts of sulfamic acid, 10 to 20 parts of glacial acetic acid, 5 to 15 parts of EDTA, 3 to 10 parts of phosphate and 1 to 5 parts of inhibitor. The high-efficiency lead removing agent provided by the application can be used for purifying lead on the surface layer of a lead brass component, is high in lead removing efficiency and long in service life, and has low corrosivity on a brass matrix, especially on zinc in the matrix; the surface lead purification process has high lead removal efficiency and low energy consumption.

Description

Lead removing agent and surface lead removing process of lead brass component
Technical Field
The application relates to but is not limited to lead removal technology, in particular to but not limited to a high-efficiency lead removal agent and a surface lead cleaning process of a lead brass component.
Background
The lead brass has good cold and hot forming performance, cutting processing performance and corrosion resistance, so that the lead brass is widely applied to the industries of electronics, daily hardware and the like. However, most of the lead brasses have high lead content (Pb is more than or equal to 1.0), are easy to separate out to pollute the environment, and can cause serious harm to human bodies when being applied to drinking water systems. Corresponding regulations are continuously provided in various countries around the world to strictly limit the content of lead in the copper alloy, and the Chinese national standard GB/T18145-2014 ceramic plate sealing water nozzle also stipulates that the precipitation amount of lead in parts of a drinking water system is less than 5 mu g/L. Therefore, it is necessary to reduce the surface lead content of the faucet in contact with water to control lead precipitation.
In recent years, related enterprises at home and abroad continuously develop the lead-removing process of the lead brass. For example, chinese patent CN 1316549a discloses a process for selectively removing lead from a water pipe made of a lead-containing copper alloy by means of a conventional pickling process, which comprises: the treated and washed pipe is immersed in a selective lead removal solution containing at least one of formic acid, acrylic acid, propionic acid and butyric acid prior to the finishing step. The process has the defects that the lead removing solution can cause serious corrosion to zinc in the brass matrix, and meanwhile, the lead removing solution contains impurities after lead removal, needs to be reconfigured and cannot be recycled. For another example, chinese patent CN 101555598A discloses a shallow surface lead removal process for bathroom faucet, which uses a mixed solution of industrial sulfuric acid and hydrochloric acid to remove lead, lead will react with sulfuric acid and hydrochloric acid to generate lead sulfate and lead chloride, and lead chloride has high solubility at 40 ℃, so that more lead chloride will dissolve in the lead removal solution, and the lead removal efficiency after multiple reactions is low.
Disclosure of Invention
The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
In this application, "wt.%" means weight percent.
The definition of lead brass in this application is: 57-65 wt.% Cu, 0.1-3.0 wt.% Pb, 0.4-1.0 wt.% Al, and the balance Zn.
The application provides an efficient lead removing agent and a surface lead cleaning process for a lead brass component, wherein the lead removing agent has high lead removing efficiency, long service life and small corrosivity on a brass matrix, particularly zinc in the matrix; the surface lead purification process has high lead removal efficiency and low energy consumption.
The application provides a high-efficiency lead removing agent, which comprises the following components in parts by weight: 60 to 80 parts of sulfamic acid, 10 to 20 parts of glacial acetic acid, 5 to 15 parts of EDTA, 3 to 10 parts of phosphate and 1 to 5 parts of inhibitor. Optionally, the lead removing agent consists of the above components.
In one embodiment provided herein, the lead remover comprises the following components in parts by weight: 70 to 80 parts of sulfamic acid, 10 to 15 parts of glacial acetic acid, 5 to 10 parts of EDTA, 3 to 8 parts of phosphate and 1 to 3 parts of inhibitor. Optionally, the lead removing agent consists of the above components. Alternatively, the lead remover may be a solid.
In one embodiment provided herein, the phosphate is selected from any one or more of a tripolyphosphate and a pyrophosphate;
in one embodiment provided herein, the EDTA is selected from one or more of di-salts of ethylenediaminetetraacetic acid and tetra-salts of ethylenediaminetetraacetic acid; optionally, the EDTA is selected from sodium salts of EDTA or calcium salts of EDTA.
In one embodiment provided herein, the mass ratio of EDTA to phosphate is (1.5 to 2): 1;
in one embodiment provided herein, the inhibitor is selected from any one or more of thiourea, sodium tungstate, cinnamaldehyde, and benzalkonium bromide; preferably, the inhibitor is thiourea.
In yet another aspect, the present application provides a surface lead-cleaning process for a lead brass component, the process comprising subjecting the lead brass component to a lead removal treatment using an aqueous solution of the above lead removal agent.
In one embodiment provided by the present application,
s1: mixing the lead removing agent with water to obtain lead removing solution;
s2: placing the lead brass component obtained in the step S1 in the lead removing solution for lead removing treatment;
in one embodiment provided by the present application, the method further comprises an operation of removing impurities on the surface of the lead brass component before the step of S1; specifically, the surface of the machined and polished lead brass component may be subjected to oil removal and wax removal treatment: electrolytic degreasing, water washing, hot dipping dewaxing, ultrasonic dewaxing and water washing; the process is a conventional process in the field, and cannot influence the subsequent lead removal treatment of the lead brass. The impurities may include grease, wax, and the like.
In one embodiment, after the step S2, an operation of removing residues on the surface of the lead brass component after the lead removal process is further included, and the processed product may be directly subjected to a plating process.
In one embodiment provided herein, the concentration of the lead removing agent in the lead removing solution is 40g/L to 60 g/L;
in one embodiment provided herein, the lead removal solution has a concentration of 45g/L to 55 g/L.
In one embodiment provided herein, the lead removing treatment is performed at a temperature of 25 ℃ to 35 ℃ for 3min to 10 min; the surface lead purification process of the lead brass component is operated at room temperature, the lead removal treatment time is less than 10min, and the process belongs to a low-energy-consumption and high-efficiency lead removal technology.
In one embodiment provided herein, the lead removal treatment is performed for a time period of 4min to 6 min.
In one embodiment provided herein, the lead removal treatment is performed under ultrasonic or stirring conditions.
In one embodiment provided herein, the step of removing impurities from the surface of the lead brass component further comprises: washing and pickling the lead brass component with surface impurities removed, wherein the pickling time is 1-3 min;
in one embodiment provided herein, the acid wash uses an acid solution having a hydrogen ion concentration of 0.02mol/L to 0.2mol/L, optionally using any one or more selected from sulfuric acid, carbonic acid, acetic acid, sulfamic acid to adjust the hydrogen ion concentration of the acid solution.
In yet another aspect, the present application discloses a lead brass component, which is obtained by the above-described surface net lead process.
In yet another aspect, the present application discloses a lead brass plated part, the lead brass being treated with the above lead remover prior to plating;
in one embodiment provided herein, the lead brass is subjected to the surface clean lead process described above prior to electroplating; preferably, the lead brass is also washed with water prior to electroplating.
Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. Other advantages of the present application may be realized and attained by the instrumentalities and methods described in the specification.
Detailed Description
Hereinafter, embodiments of the present application will be described in detail to make objects, technical solutions and advantages of the present application more apparent. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
The embodiment of the application provides a high-efficiency lead removing agent, which comprises the following components in parts by weight: 60 to 80 parts of sulfamic acid, 10 to 20 parts of glacial acetic acid, 5 to 15 parts of EDTA, 3 to 10 parts of phosphate and 1 to 5 parts of inhibitor. Optionally, the lead removing agent consists of the above components.
In the embodiment of the application, the lead removing agent comprises the following components in parts by weight: 70 to 80 parts of sulfamic acid, 10 to 15 parts of glacial acetic acid, 5 to 10 parts of EDTA, 3 to 8 parts of phosphate and 1 to 3 parts of inhibitor. Optionally, the lead removing agent consists of the above components. Alternatively, the lead remover may be a solid.
In the present examples, the phosphate is selected from any one or more of tripolyphosphates and pyrophosphates;
in the present examples, the EDTA is selected from one or more of ethylenediaminetetraacetic acid disalt and ethylenediaminetetraacetic acid tetrasalt; optionally, the EDTA is selected from sodium salts of EDTA or calcium salts of EDTA.
In the examples of the present application, the mass ratio of EDTA to the phosphate is (1.5 to 2): 1;
in the present embodiments, the inhibitor is selected from any one or more of thiourea, sodium tungstate, cinnamaldehyde, and benzalkonium bromide; preferably, the inhibitor is thiourea.
In another aspect, the present application provides a surface lead-cleaning process for a lead brass component, which includes a lead-removing treatment of the lead brass component with an aqueous solution of the above lead-removing agent.
In the embodiment of the present application, S1: mixing the lead removing agent with water to obtain lead removing solution;
s2: placing the lead brass component obtained in the step S1 in the lead removing solution for lead removing treatment;
in the embodiment of the application, the method also comprises an operation of removing impurities on the surface of the lead brass component before the step of S1; specifically, the surface of the machined and polished lead brass component may be subjected to oil removal and wax removal treatment: electrolytic degreasing, water washing, hot dipping dewaxing, ultrasonic dewaxing and water washing; the process is a conventional process in the field, and cannot influence the subsequent lead removal treatment of the lead brass. The impurities may include grease, wax, and the like.
In the embodiment of the present application, after the step S2, an operation of removing residues on the surface of the lead brass component after the lead removing process is further included, and the operated product may be directly subjected to an electroplating process.
In the embodiment of the application, the concentration of the lead removing agent in the lead removing solution is 40g/L to 60 g/L;
in the embodiment of the application, the concentration of the lead removing solution is 45g/L to 55 g/L.
In the embodiment of the application, when the lead removing treatment is carried out, the temperature of the lead removing solution is 25-35 ℃, and the lead removing treatment time is 3-10 min; the surface lead purification process of the lead brass component is operated at room temperature, the lead removal treatment time is less than 10min, and the process belongs to a low-energy-consumption and high-efficiency lead removal technology.
In the embodiment of the application, the lead removing treatment time is 4min to 6 min.
In the examples of the present application, the lead removal treatment is carried out under ultrasonic or stirring conditions.
In an embodiment of the present application, the step of removing impurities on the surface of the lead brass component further includes: washing and pickling the lead brass component with surface impurities removed, wherein the pickling time is 1-3 min;
in the embodiment of the application, the acid washing uses the hydrogen ion concentration in the acid solution of 0.02mol/L-0.2mol/L, and optionally, any one or more selected from sulfuric acid, carbonic acid, acetic acid and sulfamic acid is used for adjusting the hydrogen ion concentration of the acid solution.
In another aspect, the embodiment of the application discloses a lead brass component, which is obtained through the surface layer lead-cleaning process.
In yet another aspect, embodiments of the present application disclose a lead brass plated part, the lead brass being treated with the above lead remover prior to plating;
in the embodiment of the application, the lead brass is subjected to the surface lead cleaning process before electroplating; preferably, the lead brass is also washed with water prior to electroplating.
The technical solution of the present application is better explained by the following examples.
Example 1
The high-efficiency lead removing agent comprises the following components: sulfamic acid 70.0 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 10.0 wt.%, sodium tripolyphosphate 5.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.01mol/L sulfuric acid for 2 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 50g/L (based on the mass of the lead removing agent);
s4: putting the tap obtained in the step S2 into a lead removing solution, and carrying out lead removing treatment under stirring, wherein the temperature of the lead removing solution is maintained at 30 ℃ in the lead removing treatment process, and the treatment time is 5 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 2
The high-efficiency lead removing agent comprises the following components: sulfamic acid 64.0 wt.%, glacial acetic acid 18.0 wt.%, disodium edetate 10.0 wt.%, sodium tripolyphosphate 5.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.03mol/L sulfuric acid for 2.5 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 55g/L (based on the mass of the lead removing agent);
s4: performing lead removal treatment under stirring, wherein the temperature of a lead removal solution is maintained at 35 ℃ in the lead removal treatment process, and the treatment time is 3 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 3
The high-efficiency lead removing agent comprises the following components: sulfamic acid 72.0 wt.%, glacial acetic acid 16.0 wt.%, disodium edetate 6.0 wt.%, sodium tripolyphosphate 3.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.05mol/L sulfuric acid for 2 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 52g/L (based on the mass of the lead removing agent);
s4: performing lead removal treatment under stirring, wherein the temperature of a lead removal solution is kept at 25 ℃ in the lead removal treatment process, and the treatment time is 10 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 4
The high-efficiency lead removing agent comprises the following components: sulfamic acid 70.0 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 5.0 wt.%, sodium tripolyphosphate 10.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.07mol/L sulfuric acid for 1.5 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 45g/L (based on the mass of the lead removing agent);
s4: performing lead removal treatment under stirring, wherein the temperature of the lead removal solution is maintained at 30 ℃ in the lead removal treatment process, and the treatment time is 7 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 5
The high-efficiency lead removing agent comprises the following components: sulfamic acid 70.0 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 10.0 wt.%, sodium tripolyphosphate 5.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.1mol/L sulfuric acid for 1 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 42g/L (based on the mass of the lead removing agent);
s4: performing lead removal treatment under stirring, wherein the temperature of the lead removal solution is maintained at 28 ℃ in the lead removal treatment process, and the treatment time is 9 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 6
The high-efficiency lead removing agent comprises the following components: sulfamic acid 80.0 wt.%, glacial acetic acid 10.0 wt.%, disodium edetate 6.0 wt.%, sodium tripolyphosphate 3.0 wt.%, and thiourea 1.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.05mol/L sulfuric acid for 2 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 48g/L (based on the mass of the lead removing agent);
s4: carrying out lead removal treatment under the stirring condition, wherein the temperature of a lead removal solution is maintained at 32 in the lead removal treatment process, and the treatment time is 4 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Example 7
The high-efficiency lead removing agent comprises the following components: sulfamic acid 60.0 wt.%, glacial acetic acid 10.0 wt.%, disodium edetate 15.0 wt.%, sodium tripolyphosphate 10.0 wt.%, and thiourea 5.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process of the lead brass tap comprises the following steps:
s1: carrying out oil removal and wax removal treatment on the machined and polished faucet;
s2: washing the degreased and dewaxed faucet by 3 times of water, and then neutralizing in an aqueous solution containing 0.1mol/L sulfuric acid for 1 min;
s3: mixing the high-efficiency lead removing agent with water to prepare a lead removing solution with the concentration of 50g/L (based on the mass of the lead removing agent);
s4: performing lead removal treatment under stirring, wherein the temperature of the lead removal solution is maintained at 30 ℃ in the lead removal treatment process, and the treatment time is 6 min;
s5: washing the lead-removed faucet with 3 times of water;
s6: and (4) electroplating the tap surface obtained in the step (S5).
Comparative example 1
The lead removing agent comprises the following components: sulfamic acid 72.5 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 10.0 wt.%, sodium tripolyphosphate 5.0 wt.%, and thiourea 0.5 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 2
The lead removing agent comprises the following components: 80 wt.% of sulfamic acid, 0 wt.% of glacial acetic acid, 11.0 wt.% of disodium ethylenediamine tetraacetic acid, 6.0 wt.% of sodium tripolyphosphate and 3.0 wt.% of thiourea.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 3
The lead removing agent comprises the following components: sulfamic acid 0 wt.%, glacial acetic acid 80.0 wt.%, disodium edetate 11.0 wt.%, sodium tripolyphosphate 6.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 4
The lead removing agent comprises the following components: sulfamic acid 75.0 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 0 wt.%, sodium tripolyphosphate 10.0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 5
The lead removing agent comprises the following components: sulfamic acid 70.0 wt.%, glacial acetic acid 12.0 wt.%, disodium edetate 15.0 wt.%, sodium tripolyphosphate 0 wt.%, and thiourea 3.0 wt.%.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 6
The lead removing agent comprises the following components: 70.0 wt.% phosphoric acid, 12.0 wt.% glacial acetic acid, 10.0 wt.% disodium edetate, 5.0 wt.% sodium tripolyphosphate and 3.0 wt.% thiourea.
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The surface lead cleaning process for the lead brass taps was the same as in example 1.
Comparative example 7
The lead brass alloy has the following chemical composition: 60 wt.% Cu, 1.2 wt.% Pb, 0.6 wt.% Al, and the balance Zn.
The lead brass taps were not subjected to any net lead process treatment.
Lead precipitation of the faucet product finally obtained in the embodiment and the comparative example is tested according to the regulation of Chinese national standard GB18145-2014 ceramic wafer sealing water nozzle; the concentrations of Cu, Zn and Pb ions in the lead removing solution are tested by adopting an Atomic Absorption Spectrometry (AAS); the depth of the dezincification layer after lead removal is measured by adopting a metallographic section method. The test results are shown in table 1.
Table 1 test results of the taps of the examples and comparative examples
Figure BDA0002934825010000121
Figure BDA0002934825010000131
The lead removing agent in the embodiment 1 has low glacial acetic acid content, less corrosion to Cu and Zn in base metal, about 10 mu m of dezincification layer depth, no obvious damage to the integrity of a base material and good lead removing effect, and Pb precipitation is 1.2 mu g/L which is lower than the limit requirement of 5 mu g/L in Chinese national standard.
The lead remover of example 2 has a high glacial acetic acid content, which causes increased corrosion of Cu, Zn and Pb in the base metal, resulting in an increased ion concentration in the lead removing solution and an increase in the dezincing layer depth to 12.3. mu.m.
The lead removing agent of example 3 has reduced contents of disodium ethylenediaminetetraacetate and sodium tripolyphosphate, and can remove Cu in lead removing solution2+、Zn2+And Pb2+Reduced sequestration of ionsRemoving Pb from lead solution2+The ion solubility is increased, thereby affecting the reaction balance of Pb dissolution from the matrix, leading to the reduction of the net lead effect, and the Pb precipitation is 1.7 mug/L, but still far lower than the limit requirement of 5 mug/L in the national standard of China.
The lead removing agent of example 4 has a low content of disodium ethylenediaminetetraacetate, the content ratio of disodium ethylenediaminetetraacetate to sodium tripolyphosphate is 1:2, and the Cu content in the lead removing solution is adjusted to2+、Zn2+And Pb2+The chelating ability of the ions is weakened, and Pb in the lead solution is removed2+The ion solubility is increased, thereby affecting the reaction balance of Pb dissolution from the matrix, leading to the reduction of the net lead effect, and the Pb precipitation is 2.2 mug/L, but still far lower than the limit requirement of 5 mug/L in the national standard of China.
The concentration of the lead removing agent in the example 5 is 42g/L, the lower concentration leads to the reduction of the lead removing efficiency of the solution, and the Pb precipitation of the lead removing agent is 3.1 mu g/L, but still far lower than the limit requirement of the national standard of China of 5 mu g/L.
Example 6 the sulfamic acid content is 80%, the glacial acetic acid content is 10%, the corrosion to Cu and Zn in the base metal is less, the dezincification layer depth is about 8.8 μm, the integrity of the base material is not obviously damaged, and the lead removing effect is better, and the Pb precipitation is 3.3 μ g/L, which is lower than the limit requirement of the Chinese national standard 5 μ g/L.
Example 7 the sulfamic acid content was 60% and the glacial acetic acid content was 10%, with less corrosion of Cu and Zn in the base metal, a dezincification layer depth of about 6.8 μm, and no significant damage to the substrate integrity. The content of the disodium ethylene diamine tetraacetate and the content of the sodium tripolyphosphate are respectively 15 percent and 10 percent, so that the chelating effect of heavy metals in the lead removing liquid is ensured, the solubility of Cu, Zn and Pb ions in the lead removing liquid is lower, the lead removing effect is better, and the Pb precipitation is 3.4 mu g/L which is lower than the limit requirement of the national standard of 5 mu g/L.
The thiourea content of comparative example 1, being 0.5 wt.%, less than the minimum 1.0 wt.% required by the present application, has a reduced ability to retard corrosion of the brass matrix, and particularly the zinc in the substrate, by the deleading agent, resulting in a significant increase in the copper and zinc ion concentrations in the deleading solution and the dezincing depth of the alloy, up to 23.7 μm.
Comparative example 2 has an aminosulfonic acid content of 80%, does not contain glacial acetic acid, has minimal corrosion to Cu and Zn in the matrix metal, and has a dezincification layer depth of about 4.3 μm, but has a poor elution effect on Pb in the matrix. After lead removal treatment, the lead content of the surface layer is about 0.61 wt.%, and the Pb precipitation of the product is actually measured to be 6.9 mug/L and does not meet the limit requirement of 5 mug/L in the national standard of China.
Comparative example 3 the glacial acetic acid content was 80%, the sulphamic acid was absent, severe corrosion of the base metals, in particular Zn, was observed, and the dezincification layer depth was about 38.2 μm. The higher dezincification layer depth of the surface layer may cause waste water to remain in dezincification layer pores, which is not beneficial to the implementation of the subsequent electroplating process.
Comparative example 4 does not contain disodium ethylenediaminetetraacetate, the chelating effect on heavy metal ions such as Pb, Zn and the like in the lead removing liquid is obviously reduced, the concentration of Pb ions in the solution is increased, and the continuous dissolution of lead on the surface of the product is not facilitated, so that the lead removing effect is reduced. The Pb precipitation of the product is actually measured to be 4.3 mu g/L, which is close to the limit requirement of 5 mu g/L in the Chinese national standard, and the risk is higher.
Comparative example 5 the chelating agent contains 15% of disodium ethylene diamine tetraacetate and does not contain sodium tripolyphosphate, so that the chelating speed of zinc ions is higher, the substrate is easy to be over corroded, and the depth of a dezincification layer reaches 15.2 mu m (generally, the depth does not exceed 15 mu m, and the implementation and the quality of a subsequent electroplating process are not influenced).
Comparative example 6 adopts phosphoric acid to replace sulfamic acid, the corrosion to the base metals Cu and Zn is intensified, the dezincification layer depth reaches 17.3 μm, the dissolving-out of Pb is reduced, the Pb precipitation of the product is actually measured to be 5.2 μ g/L, and the limit requirement of the Chinese national standard of 5 μ g/L is not met. Comparative example 7 the lead removing solution was at a higher temperature (50 c) during the lead removing treatment, resulting in a decrease in the activity of the lead removing solution compared to room temperature, a decrease in the lead removing efficiency for lead brass, a Pb precipitation of more than 5 pg/L, and a non-compliance with the 5 pg/L limit of the chinese national standard.
The tap product of the comparative example 7 is directly subjected to a heavy metal precipitation performance test without a lead purification process, and the Pb precipitation is 17.2 mug/L, which does not meet the limit requirement of 5 mug/L in the Chinese national standard.
Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.

Claims (10)

1. The lead removing agent comprises the following components in parts by weight: 60 to 80 parts of sulfamic acid, 10 to 20 parts of glacial acetic acid, 5 to 15 parts of EDTA, 3 to 10 parts of phosphate and 1 to 5 parts of inhibitor.
2. The lead remover according to claim 1, wherein the lead remover comprises the following components in parts by weight: 70 to 80 parts of sulfamic acid, 10 to 15 parts of glacial acetic acid, 5 to 10 parts of EDTA, 3 to 8 parts of phosphate and 1 to 3 parts of inhibitor.
3. The lead remover according to claim 1 or 2, wherein the phosphate is selected from any one or more of tripolyphosphate and pyrophosphate;
optionally, the EDTA is selected from one or more of di-salts of ethylenediaminetetraacetic acid and tetra-salts of ethylenediaminetetraacetic acid;
optionally, the mass ratio of EDTA to the phosphate is (1.5 to 2): 1;
optionally, the inhibitor is selected from any one or more of thiourea, sodium tungstate, cinnamaldehyde, and benzalkonium bromide; preferably, the inhibitor is thiourea.
4. A surface lead-cleaning process for lead brass components, wherein the lead-cleaning process comprises subjecting a lead brass component to a lead-removing treatment using an aqueous solution of the lead-removing agent according to any one of claims 1 to 3.
5. The surface net lead process of claim 4, comprising the steps of:
s1: mixing the lead removing agent of any one of claims 1 to 3 with water to obtain a lead removing solution;
s2: placing the lead brass component obtained in the step S1 in the lead removing solution for lead removing treatment;
optionally, before the step of S1, an operation of removing impurities on the surface of the lead brass component is further included;
optionally, after the step of S2, an operation of removing residues on the surface of the lead brass component after the lead removing treatment is further included.
6. The surface lead purification process as claimed in claim 5, wherein the concentration of the lead removing agent in the lead removing solution is 40g/L to 60 g/L;
optionally, the concentration of the lead removal solution is 45g/L to 55 g/L.
7. The surface lead purification process according to claim 5 or 6, wherein the temperature of the lead removing solution is 25-35 ℃ and the lead removing time is 3-10 min when the lead removing treatment is carried out;
optionally, the lead removal treatment is for a time of 4min to 6 min.
8. The surface lead purification process as claimed in claim 5, wherein the lead removal treatment is carried out under ultrasonic or stirring conditions.
9. The surface net lead process of claim 5, wherein the step of removing surface impurities from the lead brass component further comprises: washing and pickling the lead brass component with surface impurities removed, wherein the pickling time is 1-3 min;
optionally, the acid washing uses an acid solution with a hydrogen ion concentration of 0.02mol/L to 0.2mol/L, optionally, the acid solution is adjusted with any one or more selected from sulfuric acid, carbonic acid, acetic acid, sulfamic acid.
10. A lead brass plated part treated with the lead removing agent according to any one of claims 1 to 3 before plating;
optionally, the lead brass is subjected to a surface net lead process according to any one of claims 4 to 9 prior to electroplating;
preferably, the lead brass is also washed with water prior to electroplating.
CN202110158713.0A 2021-02-04 2021-02-04 Lead removing agent and surface lead removing process of lead brass component Pending CN112981408A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1194020A (en) * 1995-08-03 1998-09-23 欧罗巴金属公开有限公司 Low lead release plumbing components made of copper basedalloys containing lead, and method for obtaining the same
CN1473209A (en) * 2000-10-31 2004-02-04 株式会社伊奈 Method for removing lead from plated cylindrical article made of lead-containing copper alloy and metal fitting for hydrant, and method for preventing leaching of lead from article made of lead-contai
CN101003899A (en) * 2007-01-17 2007-07-25 蔡开放 Deleading technique for surface of lead brass and copper alloy
WO2011130622A1 (en) * 2010-04-15 2011-10-20 Advanced Technology Materials, Inc. Method for recycling of obsolete printed circuit boards
CN103143890A (en) * 2013-03-04 2013-06-12 阮伟光 Manufacturing method for low lead copper alloy bath utensil
CN103628081A (en) * 2013-03-27 2014-03-12 北京化工大学 Metallic lead surface cleaning agent and cleaning method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1194020A (en) * 1995-08-03 1998-09-23 欧罗巴金属公开有限公司 Low lead release plumbing components made of copper basedalloys containing lead, and method for obtaining the same
CN1473209A (en) * 2000-10-31 2004-02-04 株式会社伊奈 Method for removing lead from plated cylindrical article made of lead-containing copper alloy and metal fitting for hydrant, and method for preventing leaching of lead from article made of lead-contai
CN101003899A (en) * 2007-01-17 2007-07-25 蔡开放 Deleading technique for surface of lead brass and copper alloy
WO2011130622A1 (en) * 2010-04-15 2011-10-20 Advanced Technology Materials, Inc. Method for recycling of obsolete printed circuit boards
CN103143890A (en) * 2013-03-04 2013-06-12 阮伟光 Manufacturing method for low lead copper alloy bath utensil
CN103628081A (en) * 2013-03-27 2014-03-12 北京化工大学 Metallic lead surface cleaning agent and cleaning method

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