A method for accurately detecting the phosphorus content in high-base copper-phosphorus alloy
This invention utilizes a low-temperature dissolution technique with a mixed nitric acid and hydrochloric acid to dissolve copper ions in copper-phosphorus alloys. It combines this technique with methods involving ammonia and other ammonia solutions to dissolve the sample. This method addresses the problems of instrument dependence, severe matrix interference, insufficient accuracy, and complex operation in existing technologies, enabling rapid and accurate detection of phosphorus content in high-matrix copper-phosphorus alloys.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINALCO DAYE COPPER PLATE & STRIP CO LTD
- Filing Date
- 2026-02-12
- Publication Date
- 2026-05-29
AI Technical Summary
Existing methods for detecting phosphorus content in copper-phosphorus alloys suffer from problems such as strong instrument dependence, severe matrix interference, insufficient accuracy, and complex operation, making it difficult to meet the batch testing needs of small and medium-sized enterprises.
The sample was dissolved at low temperature using a mixture of nitric acid and hydrochloric acid. The pH value was adjusted by combining ammonia and EDTA masking agent. A modified quinomolybdate precipitant was used in conjunction with polyethylene glycol dispersant. The quinomolybdate precipitant was slowly added under a simmering state and then slowly added under a boiling state. The mixture was boiled for 10-15 minutes with intermittent stirring to ensure complete precipitation of phosphorus.
It achieves rapid quantitative analysis of phosphorus content in high-matrix copper-phosphorus alloys without the need for large instruments, is easy to operate, has strong resistance to matrix interference, and provides accurate detection with a relative error of <1% and good reproducibility.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical analysis technology for metallic materials, specifically to a precise method for detecting phosphorus content in high-matrix copper-phosphorus alloys. Background Technology
[0002] Copper-phosphorus alloys are widely used brazing materials in fields such as machinery manufacturing and electronic packaging. Since the phosphorus content directly determines the alloy's melting point, fluidity, and the strength and corrosion resistance of the brazed joint, accurate quantitative detection of the phosphorus content in copper-phosphorus alloys is necessary. However, existing methods for detecting phosphorus content in copper-phosphorus alloys have the following technical shortcomings:
[0003] Inductively coupled plasma optical emission spectrometry (ICP-OES, national standard GB / T 5121.27): It has high detection accuracy, but it relies on expensive large instruments, resulting in high equipment purchase and maintenance costs, complex operation procedures (requiring professional personnel to operate), and long sample pretreatment cycle, making it difficult to meet the batch testing needs of small and medium-sized enterprises.
[0004] Traditional gravimetric method: The sample is dissolved using a single acid system, which can easily lead to the hydrolysis of copper ions or the volatilization of phosphorus. In addition, the high copper matrix and coexisting elements such as Fe and Zn are prone to co-precipitation with the precipitant, resulting in low precipitate purity and large detection deviation (relative error is usually >5%).
[0005] Conventional spectrophotometry: The color of copper ions themselves can interfere with absorbance measurement, and the color reaction is easily inhibited by coexisting elements. It requires the addition of masking agents, which is cumbersome and has limited masking effect, and has a narrow linear range (only applicable to samples with low phosphorus content).
[0006] The existing quinomolybdate gravimetric method has the following drawbacks: the reagent preparation process is not optimized for the high matrix characteristics of copper-phosphorus alloys, resulting in incomplete precipitation and difficulty in completely removing reagent residues during the washing process, leading to insufficient detection precision (RSD is usually >4%).
[0007] To address the shortcomings of the existing technologies, there is an urgent need to develop a method for detecting phosphorus content in copper-phosphorus alloys that requires no expensive instruments, is easy to operate, has strong resistance to matrix interference, and is highly accurate. Summary of the Invention
[0008] This invention provides a precise detection method for phosphorus content in high-matrix copper-phosphorus alloys. Its purpose is to overcome the shortcomings of existing detection methods, such as strong instrument dependence, severe matrix interference, insufficient accuracy, and complex operation. It provides a precise detection method for phosphorus content that is highly resistant to interference, accurate, easy to operate, and low in cost, thereby achieving rapid quantitative analysis of phosphorus in high-matrix copper-phosphorus alloys.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A precise method for detecting phosphorus content in high-matrix copper-phosphorus alloys includes the following steps:
[0011] S1: Sample pretreatment: Remove oil and oxide layer from the surface of the copper-phosphorus alloy sample and dry to constant weight.
[0012] S2: Sample dissolution and volume adjustment: Weigh the sample, place it in a nitric acid-hydrochloric acid mixture and heat at low temperature to dissolve it. After cooling, adjust the volume to obtain the test solution.
[0013] The inventors discovered that using a nitric acid-hydrochloric acid (3:1) mixed acid as the dissolving medium not only solves the problem of a single acid not being able to completely dissolve the sample, but also inhibits the hydrolysis of copper ions, thus facilitating rapid sample dissolution. The inventors also found that low-temperature heating can avoid the volatilization loss of phosphorus, improving detection accuracy.
[0014] S3: Pretreatment of the test solution: Add nitric acid, hydrochloric acid and deionized water to the test solution and boil to remove volatile impurities.
[0015] After the sample is dissolved, volatile impurities remain in the test solution. The inventors discovered that adding nitric acid, hydrochloric acid, and deionized water to the test solution and then boiling it can remove the volatile impurities.
[0016] S4: Precipitation formation: Add ammonia to the test solution to adjust the pH to 8.5-9.5, add ammonium citrate-EDTA masking agent; slowly add quinomolybdate-limonene precipitant under simmering conditions, boil for 10-15 minutes with intermittent stirring to completely precipitate phosphorus.
[0017] The inventors discovered that by adding ammonia to the test solution and maintaining the pH at 8.5-9.5, ammonium citrate can rapidly and strongly react with copper ions to form extremely stable copper-ammonia complex ions, effectively inhibiting the hydrolysis of copper ions. EDTA, as a chelating agent, can firmly complex almost all divalent and trivalent metal ions in the solution, preventing side reactions between coexisting metal ions such as iron and zinc and the precipitant, thus ensuring the purity of the precipitate measurement.
[0018] Quinoline-molybdate is a light yellow analytical reagent solution prepared from quinoline, sodium molybdate, citric acid, nitric acid, and acetone, mainly used for the detection and analysis of phosphorus content. The inventors discovered that slowly adding quinoline-molybdate precipitant under simmering conditions, boiling for 10-15 minutes with intermittent stirring, can effectively promote the complete precipitation of phosphorus.
[0019] S5: Filtration, washing, drying, and weighing.
[0020] S6: Calculate the phosphorus content.
[0021] Further improve the technical solution: In S1, ultrasonically clean with petroleum ether for 5-10 minutes, rinse with distilled water 2-3 times, dehydrate with anhydrous ethanol, and dry at 60-80℃ to constant weight.
[0022] Further improvement of the technical solution: In S2, the volume ratio of nitric acid to hydrochloric acid in the mixed acid is 3:1, and the dissolution temperature is 60-80℃.
[0023] Further improve the technical solution: In S3, add 10ml of 1:1 nitric acid, 5ml of 1:1 hydrochloric acid and 100ml of deionized water to the test solution in sequence, and boil for 3-5 minutes to remove volatile impurities.
[0024] Further improvements to the technical solution: The ratio of ammonium molybdate to citric acid in the quinomolybdate-citric acid precipitant is 1:1.5-1:2.5, and polyethylene glycol is added as a dispersant.
[0025] The existing quinoline-citric acid precipitant formulation contains five components: 70g sodium molybdate as the molybdate source to provide molybdate ions, 60g citric acid as a complexing agent to maintain an acidic environment, 85ml + 35ml nitric acid to adjust the pH of the reaction medium, 5ml quinoline as the precipitate carrier, and 280ml acetone to accelerate precipitation. The inventors discovered that increasing the proportion of citric acid and adding polyethylene glycol as a dispersant can significantly improve the precipitation rate and effectiveness of phosphorus.
[0026] Further improve the technical solution: In S5, filter the precipitate and wash it sequentially with dilute ammonia, ethanol and acetone until it is colorless. The washing order is 3-5 times with dilute ammonia, 2-3 times with ethanol and 1-2 times with acetone.
[0027] Further improve the technical solution: In S5, use deionized water to rinse the precipitate until the washing solution is neutral.
[0028] Further improve the technical solution: In S6, the formula for calculating the phosphorus content P is: In the formula, m is the mass of the precipitate, M is the mass of the sample, and k = 0.0140.
[0029] Further improvements to the technical solution: The copper content in the high-matrix copper-phosphorus alloy is 60.0-90.0%, and the coexisting elements are Fe≤5.0%, Zn≤1.0%, Sn≤0.5%, and Pb≤0.3%.
[0030] After implementing the above technical solution, compared with the prior art, the present invention can produce the following beneficial effects:
[0031] 1. Low cost and easy operation: No large instruments are required, reagents are common, and the operation steps are simple, making it suitable for batch testing in small and medium-sized enterprises;
[0032] 2. Strong resistance to matrix interference: By dissolving the sample with mixed acid and using a masking agent, the interference of copper ion hydrolysis and coexisting elements is effectively suppressed, thus effectively improving the purity of the precipitate;
[0033] 3. High precision and good reproducibility: Optimized precipitant ratio and aging conditions ensure complete precipitation and uniform particle size. The washing step effectively removes residual reagents, resulting in a relative error of <1% and RSD of <2%.
[0034] 4. Wide range of applications: Suitable for high-matrix copper-phosphorus alloys with phosphorus content of 0.05-0.2% and containing impurities such as Fe and Zn; Detailed Implementation
[0035] Preferred embodiments of the present invention are described below. Those skilled in the art should understand that these preferred embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.
[0036] Example 1: A method for accurately detecting phosphorus content in high-matrix copper-phosphorus alloys, comprising the following steps:
[0037] S1: Sample pretreatment: Remove oil and oxide layer from the surface of the copper-phosphorus alloy sample and dry to constant weight.
[0038] Several copper-phosphorus alloy samples were cut, ultrasonically cleaned with petroleum ether for 5 minutes, rinsed three times with distilled water, dehydrated with anhydrous ethanol, and dried at 70°C to constant weight.
[0039] S2: Sample dissolution and volume adjustment: Weigh 0.300g of sample and put it into 15ml of nitric acid-hydrochloric acid mixed acid (the volume ratio of nitric acid to hydrochloric acid is 3:1). Use a hot plate to heat at a low temperature (80℃) to dissolve the sample. After cooling to room temperature, adjust the volume to 100ml to obtain the test solution.
[0040] S3: Pretreatment of the test solution: Add 10ml of 1:1 nitric acid, 5ml of 1:1 hydrochloric acid and 100ml of deionized water to the test solution in sequence, and boil for 4 minutes to remove volatile impurities.
[0041] S4: Precipitation Formation: Adjust the pH to 8.5 by adding ammonia to the test solution, then add 10 ml of ammonium citrate-EDTA masking agent. Slowly add the modified quinomolybdate-limonene precipitant while simmering, boil for 10 minutes with intermittent stirring to ensure complete phosphorus precipitation. In the modified quinomolybdate-limonene precipitant, the ratio of ammonium molybdate to citric acid is 1:1.5, and polyethylene glycol is added as a dispersant.
[0042] S5: Filtration, Washing, Drying, and Weighing: Filter the precipitate and wash it sequentially with dilute ammonia, ethanol, and acetone until it becomes colorless. The washing order is: dilute ammonia 5 times, ethanol 3 times, and acetone 2 times. Dry the precipitate to constant weight and weigh it.
[0043] S6: Through formula Calculate the phosphorus content.
[0044] Example 2: A method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy, comprising the following steps:
[0045] S1: Sample pretreatment: Remove oil and oxide layer from the surface of the copper-phosphorus alloy sample and dry to constant weight.
[0046] Several copper-phosphorus alloy samples were cut, ultrasonically cleaned with petroleum ether for 8 minutes, rinsed three times with distilled water, dehydrated with anhydrous ethanol, and dried at 60°C to constant weight.
[0047] S2: Sample dissolution and volume adjustment: Weigh 0.500g of sample and put it into 15ml of nitric acid-hydrochloric acid mixed acid (the volume ratio of nitric acid to hydrochloric acid is 2.5:1). Use a hot plate to heat at a low temperature (70℃) to dissolve the sample. After cooling to room temperature, adjust the volume to 120ml to obtain the test solution.
[0048] S3: Pretreatment of the test solution: Add 10ml of 1:1 nitric acid, 5ml of 1:1 hydrochloric acid and 100ml of deionized water to the test solution in sequence, and boil for 3 minutes to remove volatile impurities.
[0049] S4: Precipitation Formation: Adjust the pH to 9.5 by adding ammonia to the test solution, then add 10 ml of ammonium citrate-EDTA masking agent. Slowly add the modified quinomolybdate-limonene precipitant while simmering, boil for 15 minutes with intermittent stirring to ensure complete phosphorus precipitation. In the modified quinomolybdate-limonene precipitant, the ratio of ammonium molybdate to citric acid is 1:2.5, and polyethylene glycol is added as a dispersant.
[0050] S5: Filtration, Washing, Drying, and Weighing: Filter the precipitate using vacuum filtration, and wash the precipitate with deionized water until the washing solution is neutral. Dry the precipitate to constant weight and weigh the precipitate.
[0051] S6: Through formula Calculate the phosphorus content.
[0052] Example 3: A method for accurately detecting phosphorus content in high-matrix copper-phosphorus alloys, comprising the following steps:
[0053] S1: Sample pretreatment: Remove oil and oxide layer from the surface of the copper-phosphorus alloy sample and dry to constant weight.
[0054] Several copper-phosphorus alloy samples were cut, ultrasonically cleaned with petroleum ether for 10 min, rinsed twice with distilled water, dehydrated with anhydrous ethanol, and dried at 60℃ to constant weight.
[0055] S2: Sample dissolution and volume adjustment: Weigh 0.450g of sample and put it into 15ml of nitric acid-hydrochloric acid mixed acid (the volume ratio of nitric acid to hydrochloric acid is 3.2:1). Use a hot plate to heat at a low temperature (60℃) to dissolve the sample. After cooling to room temperature, adjust the volume to 100ml to obtain the test solution.
[0056] S3: Pretreatment of the test solution: Add 10ml of 1:1 nitric acid, 5ml of 1:1 hydrochloric acid and 100ml of deionized water to the test solution in sequence, and boil for 5 minutes to remove volatile impurities.
[0057] S4: Precipitation Formation: Adjust the pH to 9.0 by adding ammonia to the test solution, then add 10 ml of ammonium citrate-EDTA masking agent. Slowly add the modified quinomolybdate-limonene precipitant while simmering, boil for 13 minutes with intermittent stirring to ensure complete phosphorus precipitation. In the modified quinomolybdate-limonene precipitant, the ratio of ammonium molybdate to citric acid is 1:2, and polyethylene glycol is added as a dispersant.
[0058] S5: Filtration, Washing, Drying, and Weighing: Filter the precipitate using vacuum filtration, and wash the precipitate with deionized water until the washing solution is neutral. Dry the precipitate to constant weight and weigh the precipitate.
[0059] S6: Through formula Calculate the phosphorus content.
[0060] Comparative Example: Using the traditional quinomolybdate-limonene gravimetric method to detect the same sample, the RSD was 4.8%, and the relative error was 5.2%. The above examples and comparative examples demonstrate that the phosphorus content detection method of the present invention has high precision and accuracy, and is suitable for the rapid and accurate determination of phosphorus content in high-matrix copper-phosphorus alloys.
[0061] It is worth noting that the content not described in detail in the above embodiments is prior art. It is also worth noting that any additions, subtractions, substitutions, and improvements made by those skilled in the art based on the structure and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A method for accurately detecting phosphorus content in high-matrix copper-phosphorus alloys, characterized in that: Includes the following steps: S1: Sample pretreatment: Remove oil and oxide layer from the surface of the copper-phosphorus alloy sample and dry to constant weight; S2: Sample dissolution and volume adjustment: Weigh the sample, place it in a nitric acid-hydrochloric acid mixture and heat at low temperature to dissolve it, cool it and then adjust the volume to obtain the test solution; S3: Pretreatment of test solution: Add nitric acid, hydrochloric acid and deionized water to the test solution and boil to remove volatile impurities; S4: Precipitation formation: Add ammonia to the test solution to adjust the pH to 8.5-9.5, add ammonium citrate-EDTA masking agent; slowly add quinoline molybdenum limonene precipitant under simmering conditions, boil for 10-15 minutes with intermittent stirring to completely precipitate phosphorus; S5: Filtration, washing, drying, and weighing; S6: Calculate the phosphorus content.
2. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S1, ultrasonic cleaning with petroleum ether for 5-10 minutes, rinsing with distilled water 2-3 times, dehydration with anhydrous ethanol, and drying at 60-80℃ to constant weight.
3. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S2, the volume ratio of nitric acid to hydrochloric acid in the mixed acid is 3:1, and the dissolution temperature is 60-80℃.
4. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S3, add 10 ml of 1:1 nitric acid, 5 ml of 1:1 hydrochloric acid, and 100 ml of deionized water to the test solution in sequence, and boil for 3-5 minutes to remove volatile impurities.
5. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S4, the ratio of ammonium molybdate to citric acid in the quinomolybdate-citric acid precipitant is 1:1.5-1:2.5, and polyethylene glycol is added as a dispersant.
6. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In step S5, the precipitate is filtered and washed sequentially with dilute ammonia, ethanol, and acetone until it becomes colorless. The washing order is 3-5 times with dilute ammonia, 2-3 times with ethanol, and 1-2 times with acetone.
7. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S5, the precipitate is rinsed with deionized water until the washing solution is neutral.
8. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: In S6, the formula for calculating the phosphorus content P is: In the formula, m is the mass of the precipitate, M is the mass of the sample, and k = 0.0140.
9. The method for accurately detecting phosphorus content in a high-matrix copper-phosphorus alloy as described in claim 1, characterized in that: The copper content in the high-matrix copper-phosphorus alloy is 60.0-90.0%, and the coexisting elements are Fe≤5.0%, Zn≤1.0%, Sn≤0.5%, and Pb≤0.3%.