Method for determining fluorine content in copper and copper alloy

Abstract

The invention relates to a method for measuring fluorine content in copper and copper alloy. According to the method for determining the fluorine content in the copper and the copper alloy, alkali fusion hot water extraction is not needed, phenol red is taken as an indicator, acetic acid-sodium acetate-sodium citrate-sodium chloride is taken as a total ion strength regulator, and the fluorine ion selective electrode method is adopted for determining the low-content fluorine in the copper and the copper alloy, so that the acidity and the ion strength of a solution can be adjusted; and elements such as iron and aluminum in the solution can be masked. The analysis method for measuring the low-content fluorine in the copper and the copper alloy through the fluorine ion selective electrode is high in sensitivity, high in measuring speed, easy and convenient to operate, small in interference compared with other methods, good in selectivity and capable of providing accurate data.

Description

Technical Field

[0001] The present application relates to the field of metallurgical analysis technology, and in particular to a method for determining the fluorine content in copper and copper alloys. Background Art

[0002] Copper and copper alloys are important industrial materials. So far, there has been no report on the analysis method of fluorine content in copper and copper alloys, and there are no relevant requirements in the copper and copper alloy product standards. GB / T3884.5-2012 alkaline fusion decomposition of copper and copper alloys is adopted. This method uses sodium hydroxide to melt the sample, soaks the melt with hot water and then dry filters it. The fluorine in copper and copper alloys is determined by fluoride ion selective electrode method in sodium citrate-triethanolamine medium and phenol red as indicator. For copper and copper alloys containing trace amounts of fluorine, the metal element cannot be alkali-fused, and the accuracy of the test results cannot be ensured.

[0003] Therefore, there is an urgent need for a more convenient, simple, fast and less interfering method to determine the small amount of fluorine content in copper and copper alloys. Summary of the invention

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a method for determining the fluorine content in copper and copper alloys, which can provide accurate data, has high sensitivity, fast determination speed, simple operation and less interference than other methods, and has good selectivity.

[0005] The present application provides a method for determining the fluorine content in copper and copper alloys, comprising the following steps:

[0006] S1: Prepare sample solution: weigh 0.7500 g of sample, add solvent, heat and dissolve, then cool to room temperature to obtain sample solution, transfer the sample solution to a 100 mL volumetric flask and dilute to the mark with secondary water to obtain sample solution;

[0007] S2: Prepare the sample solution to be tested: dry filter the sample solution, transfer 10 mL of the filtrate into a 100 mL volumetric flask, add 1 drop of phenol red indicator, adjust the acidity of the solution with sodium hydroxide until the solution color changes to dark blue, then adjust the acidity of the solution with nitric acid solution until the dark blue color of the solution just disappears, add 40 mL of acetic acid-sodium acetate-sodium citrate-sodium chloride total ionic strength regulator, and dilute to volume with secondary water to obtain the sample solution to be tested;

[0008] S3: Debugging electrodes: PerfectION TMConnect the composite fluoride ion electrode (Mettler Toledo) to the SevenExcellence S500-F fluoride ion meter (Mettler Toledo), and clamp the fluoride ion selective electrode on the clamp of the magnetic stirrer. Turn on the power of the multi-precision ion activity meter and the magnetic stirrer. Take an appropriate amount of secondary water in a beaker, put a magnetic stir bar into it, place it on the magnetic stirrer, insert the fluoride ion selective electrode into the beaker to a depth of 1 - 2 cm below the liquid surface, and stir magnetically until the electrode potential stabilizes below -330 V for standby testing;

[0009] S4: Determine the fluoride content in the sample solution to be measured: Place the sample solution to be measured with a volume of V in a beaker with an appropriate volume, put a magnetic stir bar into it, then place the beaker on the magnetic stirrer, insert the fluoride ion selective electrode into the sample solution to be measured to a depth of 1 - 2 cm below the liquid surface. After magnetic stirring for 2 - 3 min, when the electrode potential stabilizes, read the displayed concentration value to obtain the fluoride content in the sample;

[0010] Calculate the percentage content of fluorine in the copper and copper alloy according to the following formula:

[0011]

[0012] Where: ω is the percentage content of fluorine in the copper and copper alloy;

[0013] ρ - The mass concentration of fluorine obtained from the working curve, with the unit of μg / mL;

[0014] V0 - The total volume of the test solution, with the unit of mL;

[0015] V1 - The volume of the aliquot taken from the test solution, with the unit of mL;

[0016] V2 - The volume of the test solution for determination, with the unit of mL;

[0017] m o - The mass of the test sample, with the unit of g.

[0018] Optionally, in some schemes, the solvent in S1 is 15 mL of nitric acid, the dissolution time is 5 - 7 min, and the preparation method of the solvent is to mix concentrated nitric acid and secondary water in a volume ratio of 1:1.

[0019] Optionally, in some schemes, the concentration of phenol red in S2 is 2 g / L, and the concentration of the sodium hydroxide solution is 300 g / L.

[0020] Optionally, in some schemes, the preparation method of the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride in S2 is as follows:

[0021] Take 500 mL of high-purity water in a 1000 mL beaker, add 60 mL of glacial acetic acid, then add 58 g of sodium chloride and 12 g of sodium citrate dihydrate. After complete dissolution, adjust the acidity of the solution to pH 5.0 - 5.5 with a sodium hydroxide solution with a concentration of 300 g / L. After cooling, make up the volume to 1000 mL to obtain the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride.

[0022] Optionally, in some embodiments, the method for determining the fluorine content in copper and copper alloys further includes the following steps:

[0023] Draw a standard working curve.

[0024] Optionally, in some embodiments, the method for preparing the standard working curve is as follows:

[0025] Take 0.25 mL, 0.50 mL, 1.00 mL, 2.00 mL, and 6.00 mL of a fluorine standard solution with a concentration of 10 μg / mL and place them in 100 mL volumetric flasks respectively. Add 1 drop of phenol red indicator. If it does not show a magenta color, then adjust it to the appearance of magenta with a 300 g / L sodium hydroxide solution, and then adjust it to just turn yellow with (1 + 4) nitric acid. Add 40 mL of the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride. After making up the volume with secondary water, measure the concentration values according to the steps of debugging the electrode and the steps of determining the fluorine content in the test sample solution, and draw the standard working curve using EXCLE software.

[0026] Optionally, in some embodiments, the determination range of the method for determining the fluorine content in copper and copper alloys is: 0.025 - 0.6%.

[0027] The technical solutions provided by this application may include the following beneficial effects:

[0028] This application provides a method for determining low-content fluorine in copper and copper alloys by the fluoride ion selective electrode method without alkali fusion and hot water leaching, using acetic acid - sodium acetate - sodium citrate - sodium chloride as the total ion strength regulator. It can not only adjust the acidity and ionic strength of the solution, but also mask elements such as iron and aluminum in the solution; it has high sensitivity, fast determination speed, simple operation, less interference compared with other methods, and good selectivity, and can provide accurate data;

[0029] Through multiple inspections of low-content fluorine elements in copper and copper alloys, the application effect of this application is good; using EXCLE software to draw the standard series curve, abandoning the disadvantage of low sensitivity brought by using semi-logarithmic coordinate paper to draw the curve in the past, making the analysis results more accurate, reliable, with a wide linear range, high sensitivity, and simple operation, etc.;

[0030] Using this method to determine low-content fluorine elements in copper and copper alloys can be completed within 1 hour. The range of the analysis method can reach 0.025 - 0.6%, which expands the detection limit and is more suitable for determining low-content fluorine elements in copper and copper alloys.

[0031] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. Detailed implementation manners

[0032] In view of the above problems, the embodiments of this application provide a method for determining the fluorine content in copper and copper alloys, which can provide accurate data, has high sensitivity, fast determination speed, simple operation, less interference compared with other methods, and good selectivity at the same time.

[0033] The method for determining the fluorine content in copper and copper alloys includes the following steps:

[0034] S1: Prepare a sample solution: Weigh 0.7500 g of the sample and dissolve it by heating at low temperature for 5 - 7 min with 15 mL of nitric acid (1 + 1). The preparation method of nitric acid (1 + 1) is to mix concentrated nitric acid and secondary water in a volume ratio of 1:1, and then cool it to room temperature to obtain a test solution. Transfer the test solution to a 100 mL volumetric flask and make up the volume to the scale line with secondary water to obtain a sample solution.

[0035] S2: Prepare a sample solution to be measured: Dry-filter the sample solution, transfer 10 mL of the filtrate to a 100 mL volumetric flask, add 1 drop of phenol red indicator, the concentration of phenol red is 2 g / L, adjust the acidity of the solution with sodium hydroxide until the solution color changes to dark blue, the concentration of the sodium hydroxide solution is 300 g / L, then use nitric acid solution to adjust the acidity of the solution back until the dark blue color of the solution just disappears, add 40 mL of total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride, and make up the volume with secondary water to obtain a sample solution to be measured.

[0036] S3: Debug the electrode: Connect the perfectION TM combined fluoride ion electrode (Mettler - Toledo) with the SevenExcellence S500 - F fluoride ion meter (Mettler - Toledo), clamp the fluoride ion selective electrode on the clip of the magnetic stirrer, turn on the power of the multi - precision ion activity meter and the magnetic stirrer, take an appropriate amount of secondary water in a beaker, put in a magnetic stir bar, place it on the magnetic stirrer, insert the fluoride ion selective electrode into the beaker to a depth of 1 - 2 cm below the liquid surface, and stir magnetically until the electrode potential is stable below - 330 V for standby testing.

[0037] S4: Determine the fluorine content in the sample solution to be measured: Place the sample solution to be measured with a volume of V in a beaker with an appropriate volume. After putting a magnetic stir bar into it, place the beaker on a magnetic stirrer. Insert the fluoride ion selective electrode into the sample solution to be measured until it is 1 - 2 cm below the liquid surface. After electromagnetic stirring for 2 - 3 minutes, when the electrode potential is stable, read the displayed concentration value to obtain the fluorine content in the sample.

[0038] In this embodiment, pour 80 mL of the sample solution to be measured into a 100 mL plastic cup. After putting a magnetic stir bar into it, place the plastic cup on a magnetic stirrer. Insert the fluoride ion selective electrode into the solution until it is 1 - 2 cm below the liquid surface. After electromagnetic stirring for 2 - 3 minutes, when the electrode potential is stable, read the displayed concentration value to obtain the fluorine content in the sample.

[0039] Calculate the percentage content of fluorine in the copper and copper alloy according to the following formula:

[0040]

[0041] Where: ω is the percentage content of fluorine in the copper and copper alloy;

[0042] ρ - The mass concentration of fluorine obtained from the working curve, with the unit of μg / mL;

[0043] V0 - The total volume of the test solution, with the unit of mL;

[0044] V1 - The volume of the aliquoted test solution, with the unit of mL;

[0045] V2 - The volume of the test solution for determination, with the unit of mL;

[0046] m o - The mass of the test sample, with the unit of g.

[0047] In some embodiments, the preparation method of the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride in S2 is as follows:

[0048] Take 500 mL of high - purity water in a 1000 mL beaker, add 60 mL of glacial acetic acid, then add 58 g of sodium chloride and 12 g of sodium citrate dihydrate until completely dissolved. Adjust the acidity of the solution to pH 5.0 - 5.5 with a sodium hydroxide solution with a concentration of 300 g / L. After cooling, make up the volume to 1000 mL to obtain the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride.

[0049] In some embodiments, the method for determining the fluorine content in copper and copper alloy further includes the following steps:

[0050] Draw a standard working curve. The preparation method of the standard working curve is as follows:

[0051] Take 0.25 mL, 0.50 mL, 1.00 mL, 2.00 mL, and 6.00 mL of the fluorine standard solution with a concentration of 10 μg / mL and place them in 100-mL volumetric flasks respectively. Add 1 drop of phenolphthalein indicator. If it does not show a rose-red color, then adjust it to a rose-red color with 300 g / L sodium hydroxide solution, and then adjust it to just turn yellow with (1 + 4) nitric acid. Add 40 mL of the total ion strength regulator of acetic acid - sodium acetate - sodium citrate - sodium chloride. After making up the volume with secondary water, measure the concentration value according to the steps of debugging the electrode and the steps of measuring the fluorine content in the test sample solution, and draw a standard working curve using EXCLE software.

[0052] In some embodiments, the determination range of the method for determining the fluorine content in copper and copper alloys is: 0.025 - 0.6%.

[0053] The present application provides a method for determining low-content fluorine in copper and copper alloys by the fluoride ion selective electrode method without alkali fusion and hot water leaching, using acetic acid - sodium acetate - sodium citrate - sodium chloride as the total ion strength regulator. It can not only adjust the acidity and ionic strength of the solution, but also mask elements such as iron and aluminum in the solution; it has high sensitivity, fast determination speed, simple operation, less interference compared with other methods, and good selectivity, and can provide accurate data.

[0054] Experiment 1

[0055] Weigh copper and copper alloy sample 1# (certified value: ω F 0.020%), copper and copper alloy sample 2# (certified value: ω F 0.075%), copper and copper alloy sample 3# (certified value: ω F 0.078%), copper and copper alloy sample 4# (certified value: ω F 0.080%), copper and copper alloy samples 5#, 6#, and 7#, and measure them according to the above method. The results are shown in Table 1.

[0056] Table 1 Fluorine measurement values in fluorine determination

[0057]

[0058] Experiment 2

[0059] Weigh copper and copper alloy sample 1# (certified value: ω F 0.020%), copper and copper alloy sample 2# (certified value: ω F 0.075%), copper and copper alloy sample 3# (certified value: ω F 0.078%), copper and copper alloy sample 4# (certified value: ω F0.080%), for copper and copper alloy samples #5, #6, and #7, add standard F solution respectively; make the added F contents be 0.010%, 0.05%, 0.100%, 0.020%, 0.200%, 1.00%, and 0.500% respectively, and conduct the determination according to the above method. The results are shown in Table 2.

[0060] Table 2: Determination Results of Standard Sample Spiking Recovery

[0061] Sample F addition amount % Total measured value of F % Recovery rate % Copper and copper alloy 1# 0.010 0.0297 97 Copper and copper alloy 2# 0.050 0.125 102 Copper and copper alloy 3# 0.100 0.173 96 Copper and copper alloy 4# 0.020 0.104 100 Copper and copper alloy 5# 0.200 0.232 100.5 Copper and copper alloy 6# 1.00 1.054 101.2 Copper and copper alloy 7# 0.500 0.578 102.6

[0062] Through the verification of the above embodiments, it can be seen that when using the method of the present invention to determine low-content fluorine elements in copper and copper alloys, the range of the analysis method can be from 0.025% to 0.6%, the detection limit is extended, and it is more suitable for determining low-content fluorine elements in copper and copper alloys. The analysis method has high precision and high accuracy. This method is fast and simple, and can be popularized and used in production.

[0063] Finally, it should also be noted that in this article, relationships such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms including, containing or any other variant are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0064] The embodiments of the present application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications or improvements to the technology in the market, or to enable other ordinary technical personnel in the technical field to understand the embodiments disclosed herein.

Claims

1. A method for determining the fluorine content in copper and copper alloys, characterized in that: The method for determining the fluorine content in copper and copper alloys comprises the following steps: S1: Prepare sample solution: weigh 0.7500 g of sample, add solvent, heat and dissolve, then cool to room temperature to obtain sample solution, transfer the sample solution to a 100 mL volumetric flask and dilute to the mark with secondary water to obtain sample solution; S2: Prepare the sample solution to be tested: dry filter the sample solution, transfer 10 mL of the filtrate into a 100 mL volumetric flask, add 1 drop of phenol red indicator, adjust the acidity of the solution with sodium hydroxide until the solution color changes to dark blue, then adjust the acidity of the solution with nitric acid solution until the dark blue color of the solution just disappears, add 40 mL of acetic acid-sodium acetate-sodium citrate-sodium chloride total ionic strength regulator, and dilute to volume with secondary water to obtain the sample solution to be tested; S3: Debugging electrodes: PerfectION TM The composite fluoride ion electrode (Mettler-Toledo) was connected to the Seven Excellence S500-F fluoride ion meter (Mettler-Toledo) and the fluoride ion selective electrode was clamped on the clip of the magnetic stirrer. The multi-precision ion activity meter and the magnetic stirrer were powered on. An appropriate amount of secondary water was put into a beaker and a magnetic stirrer was placed on the magnetic stirrer. The fluoride ion selective electrode was inserted into the beaker to 1-2 cm below the liquid surface and electromagnetically stirred until the electrode potential was stabilized below -330 V for standby testing. S4: Determine the fluorine content in the sample solution: place the sample solution with a volume of V in a beaker of suitable volume, put a magnetic stirrer in it and place the beaker on a magnetic stirrer, insert the fluorine ion selective electrode into the sample solution to 1-2 cm below the liquid surface, stir by electromagnetic for 2-3 minutes, read the displayed concentration value after the electrode potential is stable, and thus obtain the fluorine content in the sample; The percentage of fluorine in the copper and copper alloy is calculated according to the following formula: Wherein: ω is the percentage of fluorine in the copper and copper alloy; ρ-mass concentration of fluorine obtained from the working curve, in μg / mL; V0-total volume of test solution, in mL; V1-the volume of the test solution taken, in mL; V2-volume of test solution, in mL; m o - Sample mass, in g.

2. The method for determining the fluorine content in copper and copper alloys according to claim 1, characterized in that: The solvent in S1 is 15 mL of nitric acid, the dissolution time is 5-7 min, and the solvent is prepared by mixing concentrated nitric acid and secondary water in a volume ratio of 1:

1.

3. The method for determining the fluorine content in copper and copper alloys according to claim 1 or 2, characterized in that: The concentration of phenol red in the S2 is 2 g / L, and the concentration of the sodium hydroxide solution is 300 g / L.

4. The method for determining the fluorine content in copper and copper alloys according to claim 3, characterized in that: The preparation method of the acetic acid-sodium acetate-sodium citrate-sodium chloride total ionic strength regulator in S2 is: 500 mL of high-purity water is placed in a 1000 mL beaker, 60 mL of glacial acetic acid is added, and then 58 g of sodium chloride and 12 g of sodium citrate dihydrate are added until they are completely dissolved, and the acidity of the solution is adjusted to a pH of 5.0 to 5.5 with a 300 g / L sodium hydroxide solution, and the solution is cooled and fixed to 1000 mL to obtain the acetic acid-sodium acetate-sodium citrate-sodium chloride total ionic strength regulator.

5. The method for determining the fluorine content in copper and copper alloys according to claim 4, characterized in that: The method for determining the fluorine content in copper and copper alloys also includes the following steps: Draw a standard working curve.

6. The method for determining the fluorine content in copper and copper alloys according to claim 5, characterized in that: The preparation method of the standard working curve is: Take 0.25ml, 0.50ml, 1.00ml, 2.00ml and 6.00ml of the fluorine standard solution with a concentration of 10ug / mL and place them in a 100mL volumetric flask respectively, add 1 drop of phenol red indicator, if it does not show rose red, adjust it to rose red with 300g / L sodium hydroxide solution, and then adjust it to just turn yellow with (1+4) nitric acid, add 40mL of the acetic acid-sodium acetate-sodium citrate-sodium chloride total ion strength regulator, make up to volume with secondary water, determine the concentration value according to the electrode debugging step and the step of determining the fluorine content in the sample solution to be tested, and use EXCLE software to draw a standard working curve.

7. The method for determining the fluorine content in copper and copper alloys according to claim 6, characterized in that: The measuring range of the method for measuring the fluorine content in copper and copper alloy is: 0.025-0.6%.

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