Method for electrolytic detection of chemical components of tin bronze

Abstract

The invention relates to the technical field of alloy element detection, and discloses a method for electrolytic detection of chemical components of tin bronze, which comprises the following steps: dissolving copper in a solvent dilute nitric acid, reacting the solvent with tin to generate a precipitate, filtering to remove the tin element, electrolyzing, adding urea and concentrated sulfuric acid in the electrolytic process, and adding sodium hydroxide and sodium hydroxide in the electrolytic process; the solution is kept clear in the electrolysis process, and copper is stably loaded on the cathode net of the platinum electrode after electrolysis and does not fall off. The content of most copper is detected through electrolysis, then the content of residual copper in the electrolyzed solution is measured through an ICP-OES method, and finally the total amount of the copper element is obtained. According to the method, the content of residual copper in the electrolyzed solution measured by the ICP-OES method is accurate by using the simple and clear liquid, meanwhile, the influence of the tin element on the electrolysis process is avoided, the detection of the copper element in tin bronze of different marks can be accurately and quickly realized, and the method has great popularization and application values.

Description

Technical Field

[0001] This invention relates to the field of alloy element detection technology, and specifically to a method for electrolytic detection of the chemical composition of tin bronze. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] Tin bronze, a non-ferrous metal material with copper as the matrix and tin as the main alloying element (typically containing 3%-14% tin), plays an irreplaceable role in shipbuilding, chemical industry, machinery manufacturing, and electronic instrumentation. Its excellent corrosion resistance, wear resistance, and mechanical properties make it the preferred material for key components such as bearings, gears, and valves. In tin bronze, copper, as the matrix element, directly affects the phase composition and mechanical properties of the alloy. For example, when the copper content is higher than 85%, the alloy forms an α-solid solution, exhibiting good plasticity; while when the tin content increases, a hard and brittle δ-phase (Cu) forms. 31 An increase in Sn8 leads to increased hardness but decreased ductility. Tin bronze has many different grades, each with unique characteristics and applications. The copper content in tin bronze is one of the key factors in evaluating the alloy's performance, and it is of great significance for ensuring the alloy's performance stability, controllable production quality, and resource utilization. Therefore, it is essential to accurately determine the copper content of different grades of tin bronze.

[0004] Currently, the determination of copper content in tin bronze mainly relies on physicochemical analysis methods. Various methods differ significantly in application scenarios and accuracy. For example, atomic absorption spectrometry, chemical titration, and spectrophotometry each have their advantages and disadvantages, and all have the problem of complex preparation and processing.

[0005] When determining the copper content in tin bronze, direct electrolysis of tin bronze will cause tin and copper to enter the solution simultaneously. The hydrolysis products of tin will accumulate in the solution, deteriorating its properties, compromising its stability, and hindering the electrolysis process. Currently, the main mixed solutions used for electrolytic detection of tin bronze samples are those containing nitric acid, sulfuric acid, and water, and those containing hydrochloric acid, nitric acid, and water. The mixed solution of nitric acid, sulfuric acid, and water (7+10+25) has the disadvantage that when the tin content of the sample is high, the solution will become turbid, hindering the electrolysis process and making detection difficult. Furthermore, impurities such as lead and arsenic in the solution will precipitate simultaneously with copper on the platinum cathode grid, resulting in a darker appearance of the reduced copper on the cathode. The mixed solution of hydrochloric acid, nitric acid, and water (6+16+28) has the disadvantage that during electrolysis, the reduced copper tends to form a spongy texture on the platinum cathode grid, resulting in weak adhesion and easy detachment. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned technical problems by providing an electrolytic detection method for the chemical composition of tin bronze. By selecting and controlling the optimal current, reagent addition, and electrolysis time during the electrolysis process, this invention achieves the effect of detecting the copper content in tin bronze by electrolysis, with simple and rapid sample processing, good repeatability, and high accuracy of the measurement results.

[0007] The technical solution of the present invention is as follows: A method for electrolytic detection of the chemical composition of tin bronze includes the following steps: Step S1: Dissolve the tin bronze sample in a solvent and slowly heat it to allow most of the copper elements to enter the mixed solution; Step S2: After dissolution, filter the solution with filter paper, take the liquid portion, and electrolyze it in an electrolyte. Urea and sulfuric acid are also added to the electrolyte. The content of most copper elements in the mixed solution is determined by electrolysis. Then, the content of residual copper in the solution after electrolysis is determined by ICP-OES. Finally, the total amount of copper is calculated.

[0008] Preferably, the solvent in step S1 is dilute nitric acid. The volume concentration of the dilute nitric acid is 45%-55%. The nitric acid concentration (ρ) is 1.42 g / ml.

[0009] Preferably, in step S2, the urea solution has a mass concentration of 16%. The sulfuric acid is concentrated sulfuric acid with a concentration of ρ = 1.84 g / ml. The concentrated sulfuric acid is analytical grade or superior grade. From a cost perspective, analytical grade is preferred.

[0010] Preferably, in step S1, the solvent is heated at a low temperature, and the furnace plate temperature of the heating furnace is ≤120°C.

[0011] In step S1, during the reaction, after the tin bronze sample is dissolved in the solvent, the tin in the solution continues to react with nitric acid to generate stannic acid, which is insoluble in water. The stannic acid generated in step S1 can be filtered out using filter paper.

[0012] In step S2, the solution after filtering stannic acid is clear. At the same time, the solution remains clear after electrolysis, making it suitable for accurate determination of copper content in the solution using the ICP-OES method.

[0013] Preferably, in step S2, the electrolysis process is as follows: First electrolysis process: Electrolyze with a current of 3A for 50-60 minutes; Second electrolysis process: Electrolyze for 10-20 minutes using a current of 2A.

[0014] The urea solution was added in two stages: first, 2 ml was added before the start of the first electrolysis process; second, 2 ml was added after the first electrolysis process ended and before the start of the second electrolysis process. Concentrated sulfuric acid was added 30 minutes after the start of the first electrolysis process, in a volume of 2 ml.

[0015] The urea solution used in the reagent addition during the electrolysis process in this invention needs to be freshly prepared before use.

[0016] Preferably, the method of this application is applicable to the use of tin bronze with a tin content of ≤10%.

[0017] Compared with existing technologies, the advantages of this invention are: 1. A method for electrolytic detection of the chemical composition of tin bronze. This invention improves the accuracy of copper determination during electrolysis by optimizing the selection of solvent and removing interfering tin elements. By further optimizing the optimal current, adding urea and sulfuric acid to the electrolyte, and selecting and applying the electrolysis time, the method ensures the smooth progress of the tin bronze electrolysis process and the accurate determination of copper elements, achieving rapid and efficient detection with good repeatability and high accuracy. 2. A method for electrolytic detection of the chemical composition of tin bronze, which does not require additional investment in experimental modifications and can complete the detection test using only existing chemical reagents; the innovative method uses a solvent reaction to remove interfering element tin before the start of electrolysis, thereby ensuring the smooth progress of the subsequent copper element electrolysis process, solving the problem that existing technologies cannot determine the copper content in tin bronze by electrolysis; and the innovative method adds urea and concentrated sulfuric acid in stages during the subsequent electrolysis process, further optimizing the electrolysis process, controlling the copper element morphology and stabilizing the load, and, in conjunction with the electrolysis time and current conditions, ultimately achieving a highly efficient copper element load in tin bronze. Attached Figure Description

[0018] Figure 1 This is a diagram showing the effect of filtering a tin bronze (ZQSn5-5-5) sample dissolved in the solvent of the present invention in Example 1 of this invention; Figure 2 This is a diagram showing the effect of electrolysis of the tin bronze (ZQSn5-5-5) sample dissolved in the solvent of the present invention in Example 1 of the present invention; Figure 3 This is a diagram showing the effect of filtering the tin bronze (ZQSn5-5-5) sample dissolved in a mixed solution of nitric acid and sulfuric acid in Comparative Example 1 of this invention; Figure 4 This is a process diagram of dissolving tin bronze (ZQSn5-5-5) sample with a mixed solution of nitric acid and sulfuric acid in Comparative Example 1 of this invention. In the diagram, A is a schematic diagram of the sample being difficult to dissolve; B is a diagram of the effect of the electrolysis process. Figure 5This is a diagram showing the effect of filtering the tin bronze (ZQSn5-5-5) sample dissolved in a mixed solution of hydrochloric acid and nitric acid in Comparative Example 2 of this invention; Figure 6 This is a diagram showing the effect of electrolysis process of dissolving tin bronze (ZQSn5-5-5) sample in a mixed solution of hydrochloric acid and nitric acid in Comparative Example 2 of this invention; Figure 7 This is a diagram showing the effect of filtering a tin bronze (ZQSn4-4-4) sample dissolved in the solvent of the present invention in Example 2 of the present invention.

[0019] Figure 8 This is a diagram showing the effect of electrolysis of the tin bronze (ZQSn4-4-4) sample dissolved in the solvent of the present invention in Example 2 of the present invention.

[0020] Figure 9 This is a diagram showing the effect of filtering the tin bronze (ZQSn4-4-4) sample dissolved in a mixed solution of nitric acid and sulfuric acid in Comparative Example 3 of this invention.

[0021] Figure 10 This is a diagram showing the effect of electrolysis of tin bronze (ZQSn4-4-4) sample dissolved in a mixed solution of nitric acid and sulfuric acid in Comparative Example 3 of this invention.

[0022] Figure 11 This is a diagram showing the effect of filtering the tin bronze (ZQSn4-4-4) sample dissolved in a mixed solution of hydrochloric acid and nitric acid in Comparative Example 4 of this invention.

[0023] Figure 12 This is a diagram showing the effect of electrolysis on the tin bronze (ZQSn4-4-4) sample dissolved in a mixed solution of hydrochloric acid and nitric acid in Comparative Example 4 of this invention. Figure 13 This is a comparison chart of the electrolysis results of the sample with 20% urea added in Comparative Example 5 of this invention. Detailed Implementation

[0024] The specific embodiments listed in this invention are merely examples, and the invention is not limited to the specific embodiments described below. For those skilled in the art, any equivalent modifications and substitutions to the embodiments described below are also within the scope of this invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of this invention should be covered within its scope. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are commercially available conventional products. To better illustrate this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this invention can be practiced even without certain specific details. In other embodiments, methods, means, equipment, and steps well known to those skilled in the art are not described in detail in order to highlight the main points of this invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Unless otherwise specified, all units used in this specification are International Standard Units (SI), and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors unavoidable in industrial production.

[0026] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0027] Example 1 Determination of copper content in tin bronze of grade ZQSn5-5-5: The solvent was dilute nitric acid with a volume concentration of 50%. Nitric acid ρ = 1.42 g / ml, sulfuric acid ρ = 1.84 g / ml. The mass ratio of urea to distilled water in the urea solution was 1:5.

[0028] Step S1: Weigh 1g of tin bronze, accurate to 0.0001g. Place the tin bronze sample in a 250mL beaker, slowly add 20mL of solvent along the rim, heat at 100℃ to dissolve, and expel the yellow gas. If the solution reacts violently during dissolution, briefly remove it from the heating plate. Continue to add 40mL of distilled water and shake well. After dissolution, filter the solution with filter paper, and dilute the solution with distilled water to 150mL. Pour the solution into a beaker and set aside for later use. Step S2: Install the dried and weighed platinum electrode mesh on the cathode and anode of the electrolyzer, with the larger mesh electrode serving as the cathode (hereinafter referred to as the platinum cathode mesh) and the smaller mesh electrode serving as the anode. Place the anode inside the inner ring of the cathode, adjust the concentricity of the two electrodes, and finally immerse the two electrodes in the solution to be used prepared in step S1, with about 1 / 3 of the electrode mesh exposed above the liquid surface.

[0029] Connect the power supply, adjust the current to 3A, and then turn on the electromagnetic stirrer to thoroughly mix the solution. Next, add 2mL of urea solution and electrolyze for 30 minutes. Then, add 2mL of concentrated sulfuric acid and continue electrolyzing for 20 minutes. Add another 2mL of urea solution while reducing the current to 2A and exposing about 1 / 4 of the platinum electrode mesh above the liquid surface. Continue electrolyzing for 10 minutes until no more copper is deposited on the immersed platinum cathode mesh.

[0030] Turn off the electrolysis switch, remove the platinum cathode mesh from the solution, rinse the area around the mesh with distilled water, then immerse it briefly in anhydrous ethanol, and finally dry it in a 100°C oven for 3 minutes. After drying, remove the platinum cathode mesh, cool it in a desiccator, and weigh it to calculate the copper content. Then, transfer the solution from the beaker to a 200mL volumetric flask and dilute to volume, shaking well. After electrolysis, the solution will be clear; determine the copper content using ICP-OES. Finally, combine the copper content results obtained from the two methods to obtain the final copper content.

[0031] The results of copper element measurement in tin bronze are as follows:

[0032] like Figure 1 and Figure 2 As shown, the solution was clear during the electrolysis process, with no precipitate or impurities produced, and the copper adhered firmly to the platinum cathode mesh.

[0033] Comparative Example 1 The other contents are the same as in Example 1, except that urea and concentrated sulfuric acid are not added during the electrolysis process. Nitric acid ρ = 1.42 g / ml, sulfuric acid ρ = 1.84 g / ml.

[0034] The solvent composition is nitric acid + sulfuric acid + distilled water (7 + 10 + 25).

[0035] Step S1: Place the tin bronze sample into a 250mL beaker, add 20mL of solvent, heat at 100℃ to dissolve, continue to add 40mL of distilled water and shake well. After dissolution, filter the solution with filter paper and dilute the solution with distilled water to 150mL for later use.

[0036] Step S2: The electrolysis process is the same as in Example 1, but urea and concentrated sulfuric acid are not added to the solution.

[0037] The measurement results are as follows Figure 3 and Figure 4 As shown: The sample could not be completely dissolved during the dissolution process, and the electrolysis reaction was incomplete, which affected the measurement results. In addition, impurities such as lead and arsenic in the solution were deposited on the platinum cathode grid at the same time as copper, which caused the reduced copper deposited on the platinum cathode grid to appear black.

[0038] Comparative Example 2 The other contents are the same as in Example 1, except that urea and concentrated sulfuric acid are not added during the electrolysis process. Nitric acid ρ = 1.42 g / ml, hydrochloric acid ρ = 1.19 g / ml.

[0039] The solvent composition is nitric acid + hydrochloric acid + distilled water (6 + 16 + 28).

[0040] Step S1: Place the tin bronze sample into a 250mL beaker, add 20mL of solvent, heat to dissolve, continue to add 40mL of distilled water and shake well. After dissolution, filter the solution with filter paper and dilute the solution with distilled water to 150mL for later use.

[0041] Step S2: The electrolysis process is the same as in Example 1. During the electrolysis process, the copper on the platinum cathode grid is spongy and unstable, which affects the measurement results.

[0042] The measurement results are as follows Figure 5 and Figure 6 As shown: During electrolysis, the reduced copper forms a sponge-like structure on the platinum cathode mesh, making it weakly attached and prone to detachment. The detached reduced copper cannot be collected, leading to inaccurate weighing and consequently, impaired detection.

[0043] Example 2 The difference between this embodiment and Embodiment 1 is that the tin bronze grade is ZQSn4-4-4. All other aspects are the same as in Embodiment 1.

[0044] The tin bronze sample prepared by this solvent is fully dissolved. It can be directly electrolyzed after filtering out the stannic acid with filter paper. The solution is clear after electrolysis and the copper content in the solution can be determined directly by ICP-OES.

[0045] The results of copper element measurement in tin bronze are as follows:

[0046] like Figure 7 and Figure 8 As shown, the solution is clear during electrolysis, with no precipitate or impurities produced, and the copper adheres firmly to the platinum cathode mesh.

[0047] Comparative Example 3 The other contents are the same as in Example 2, except that urea and concentrated sulfuric acid are not added during the electrolysis process. Nitric acid ρ = 1.42 g / ml, sulfuric acid ρ = 1.84 g / ml.

[0048] The solvent composition is nitric acid + sulfuric acid + distilled water (7 + 10 + 25).

[0049] Step S1: Place the tin bronze sample into a 250mL beaker, add 20mL of solvent, heat to dissolve, continue to add 40mL of distilled water and shake well. After dissolution, filter the solution with filter paper and dilute the solution with distilled water to 150mL for later use.

[0050] Step S2: The electrolysis steps are the same as in Example 2. The solution becomes turbid after filtration. The turbidity of the solution during electrolysis indicates that the electrolysis reaction is incomplete and affects the measurement results.

[0051] The measurement results are as follows Figure 9 and Figure 10 As shown: The electrolyte becomes turbid during electrolysis, which prevents the electrolysis process from proceeding smoothly. Furthermore, the turbid electrolyte cannot be used for copper recovery determination using an ICP emission spectrometer.

[0052] Comparative Example 4 The other contents are the same as in Example 2, except that urea and concentrated sulfuric acid are not added during the electrolysis process. Nitric acid ρ = 1.42 g / ml, hydrochloric acid ρ = 1.19 g / ml.

[0053] The solvent composition is nitric acid + hydrochloric acid + distilled water (6 + 16 + 28).

[0054] Step S1: Place the tin bronze sample into a 250mL beaker, add 20mL of solvent, heat to dissolve, continue to add 40mL of distilled water and shake well. After dissolution, filter the solution with filter paper and dilute the solution with distilled water to 150mL for later use.

[0055] Step S2: The electrolysis process is the same as in Example 2. During the electrolysis process, the copper on the platinum cathode grid is spongy and unstable, which affects the measurement results.

[0056] The measurement results are as follows Figure 11 and Figure 12 As shown: During electrolysis, the reduced copper forms a sponge-like structure on the platinum cathode mesh, making it weakly attached and prone to detachment. The detached reduced copper cannot be collected, leading to inaccurate weighing and consequently, impaired detection.

[0057] Example 3 The difference between this embodiment and Embodiment 1 is that the tin bronze grade is 5-5-5. All other aspects are the same as in Embodiment 1.

[0058] The tin bronze sample prepared by this solvent is fully dissolved. It can be directly electrolyzed after filtering out the stannic acid with filter paper. The solution is clear after electrolysis and the copper content in the solution can be determined directly by ICP-OES.

[0059] The results of copper element measurement in tin bronze are as follows:

[0060] The solution is clear during electrolysis, with no precipitate or impurities produced, and the copper adheres firmly to the platinum cathode mesh.

[0061] Example 4 The difference between this embodiment and Embodiment 1 is that the tin bronze grade is 6-6-3. All other aspects are the same as in Embodiment 1.

[0062] The tin bronze sample prepared by this solvent is fully dissolved. It can be directly electrolyzed after filtering out the stannic acid with filter paper. The solution is clear after electrolysis and the copper content in the solution can be determined directly by ICP-OES.

[0063] The results of copper element measurement in tin bronze are as follows:

[0064] The solution is clear during electrolysis, with no precipitate or impurities produced, and the copper adheres firmly to the platinum cathode mesh.

[0065] By employing the selection of solvents for tin bronze, the removal of tin from the solution, and the optimal selection of current, reagent addition, and electrolysis time during the electrolysis process, this invention avoids the destructive effects of tin hydrolysis products on the stability of the electrolytic solution, ensuring the smooth progress of the tin bronze electrolysis process. This invention uses ICP-OES to compensate for copper recovery, solving the problem of not being able to determine the copper content in tin bronze using electrolysis. It is applicable to the detection of copper content in various grades of tin bronze samples, with good repeatability and high accuracy. This invention does not require additional investment in experimental modifications; the detection can be completed using existing chemical reagents, achieving significant results in reducing detection costs, improving the accuracy of detection results, and especially in terms of efficiency and speed.

[0066] Comparative Example 5 The difference between this comparative example and Example 1 is that the mass ratio of urea to distilled water in the urea solution is 1:4, and the mass concentration of the urea solution is 20%. All other steps are exactly the same as in Example 1.

[0067] For example, the measurement results are... Figure 13 As shown: like Figure 13 (The left image shows a urea concentration of 16%, and the right image shows a urea concentration of 20%). In the left image, copper is stably loaded on the platinum cathode grid (the platinum cathode is gently moved on a piece of white paper, and no scratches appear on the paper). In the right image, two phenomena are observed: 1. The copper loaded on the platinum cathode grid is unstable (the platinum cathode is gently moved on a piece of white paper, and some black scratches appear on the paper); 2. The copper loaded on the platinum cathode grid is darker (i.e., impurity elements in the electrolyte, such as lead and arsenic, are deposited on the platinum cathode grid along with the copper).

[0068] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for electrolytic detection of the chemical composition of tin bronze, characterized in that, Includes the following steps: Step S1: Dissolve the tin bronze sample in a solvent and slowly heat it to allow the copper element to enter the solvent; Step S2: After dissolution, filter with filter paper, take the liquid portion, and electrolyze it in an electrolyte. Urea and sulfuric acid are also added to the electrolyte. The content of most copper elements in the solvent is determined by electrolysis, and the content of residual copper in the solution after electrolysis is determined by ICP-OES. Finally, the total amount of copper elements is calculated.

2. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, The solvent in step S1 is dilute nitric acid, and the volume concentration of the dilute nitric acid is 45-55%.

3. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, The slow heating in step S1 specifically involves heating the solvent at a temperature not exceeding 120°C.

4. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, In step S2, the mass concentration of urea is 16%, and the sulfuric acid is concentrated sulfuric acid.

5. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, In step S2, electrolysis includes the following processes: First electrolysis process: Electrolyze with a current of 3A for 50-60 minutes; Second electrolysis process: Electrolyze again with a current of 2A for 10-20 minutes.

6. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, In step S2, the urea solution is added in two parts. The first part is 2 ml added before the start of the first electrolysis process; the second part is 2 ml added after the end of the first electrolysis process and before the start of the second electrolysis process.

7. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, In step S2, the concentrated sulfuric acid is added 30 minutes after the start of the first electrolysis process, and the amount added is 2 ml.

8. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, The tin content of the tin bronze is ≤10%.

9. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, The mass ratio of the tin bronze sample to the solvent was 1g:20ml.

10. The method for electrolytic detection of the chemical composition of tin bronze according to claim 1, characterized in that, The electrolysis was performed using a platinum electrode mesh electrolyzer.

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