Quality control samples of silver impurities and their preparation methods

Abstract

The present application provides a series of quality control samples of impurities in silver and a preparation method thereof, which belongs to the field of chemical quality control sample preparation. The first impurity sample is obtained by wrapping a first group of metals with silver sheets and burying them in silver powder, heating and melting them in a vacuum environment, adding a second group of metals to melt, and casting; repeating the melting and casting process twice to obtain a second impurity sample and a third impurity sample respectively, and then rolling the sheet to obtain a series of quality control samples of impurities in silver. The present application prepares high-content impurity element samples by means of step-by-step smelting and quenching processes, and uses them as raw materials for dilution, thereby ensuring that low-content impurity elements are uniformly and stably melted into silver, improving the controllability of the impurity element content, and ensuring that the prepared quality control samples are uniform and reliable. In addition to the main element silver, the series of quality control samples of impurities in silver provided by the present application contain 10 elements including gold, bismuth, copper, iron, lead, palladium, antimony, selenium, tellurium, and zinc, which can meet the quality control requirements of the entire process of high-silver alloy detection.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical quality control sample preparation, and in particular to a series of quality control samples of impurities in silver and a preparation method thereof. Background Art

[0002] The determination of high-content silver alloys refers to the detection of alloys with a silver content exceeding 999‰. The subtraction method is generally used, that is, the alloy is digested with acid and then the content of other elements except silver is detected by inductively coupled plasma optical emission spectrometry (ICP-OES). Finally, the silver content is calculated by subtraction. However, this method has some challenges in actual operation. During the sample digestion, transfer and volume determination process, the sample may be lost. In addition, the detection instrument itself may also fluctuate, resulting in inaccurate final test results. Therefore, high-silver alloy quality control samples that can be subjected to full-process quality control are crucial for the determination of high-content silver alloys. However, there is currently a lack of quality control samples specifically for high-silver alloys on the market, which makes it difficult for laboratories to conduct effective full-process monitoring during the detection process and cannot fully meet actual needs.

[0003] In view of this, it is necessary to design an improved series of quality control samples for impurities in silver and a preparation method thereof to solve the above problems. Summary of the Invention

[0004] In view of the technical problems existing in the background technology, the present application provides a series of quality control samples of impurities in silver and a preparation method thereof, aiming to solve the technical problem of low accuracy of the determination results of high-content silver alloys.

[0005] In a first aspect, the present application provides a method for preparing a series of quality control samples of impurities in silver, comprising the following steps:

[0006] S1. Weigh eight impurity metal elements, brass, and pure silver, respectively. The eight impurity metal elements are Au, Bi, Fe, Pb, Pd, Sb, Se, and Te; the pure silver includes silver flakes and silver powder; Bi, Pb, Sb, Se, Te, and brass are considered as the first group of metals, and Au, Fe, and Pd are considered as the second group of metals;

[0007] S2. Wrap the first group of metals with silver sheets and place them in a container with silver powder on the bottom, covering the silver powder and burying the inclusions; place the container in a vacuum environment, and preheat the container by heating it at a predetermined rate to a first predetermined temperature. Thereafter, heat it to a second predetermined temperature and maintain it for a predetermined time. After all the metals have melted, add the second group of metals, continue heating it to a third predetermined temperature under magnetic stirring, and after all the metals have melted, cast it into a preheated mold, solidify it, cool it, quench it, clean it, and dry it to obtain a first impurity sample;

[0008] S3. intercepting the first impurity sample and placing it in a container with silver powder on the bottom, covering the sample with the silver powder; placing the container in a vacuum environment, heating the container at a predetermined rate to a first preset temperature to preheat the container, then heating the container to a second preset temperature and holding the temperature for a predetermined time, and then heating the container to a third preset temperature under magnetic stirring. After the metal is completely melted, the container is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a second impurity sample;

[0009] S4. intercepting the second impurity sample, placing it in a container with silver powder on the bottom, covering the sample with the silver powder; placing the container in a vacuum environment, heating it to a first preset temperature at a predetermined rate to preheat the container, then heating it to a second preset temperature and holding it for a predetermined time, and then heating it to a third preset temperature under magnetic stirring. After the metal is completely melted, the container is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a third impurity sample;

[0010] S5. The first impurity sample, the second impurity sample, and the third impurity sample are subjected to sheet rolling to obtain a series of quality control samples of silver impurities.

[0011] As a further improvement of the present application, in step S1, the purity of the impurity element metal and pure silver is not less than 99.99%.

[0012] As a further improvement of the present application, the brass is a copper-zinc alloy with a purity of not less than 99.99%.

[0013] As a further improvement of the present application, the first preset temperature is 450-550°C, and the heating rate is 15-20°C / min.

[0014] As a further improvement of the present application, the second preset temperature is 950~1050℃, and the insulation time is 10~20min; the third preset temperature is 1450~1550℃, and the insulation time is 1~3min.

[0015] As a further improvement of the present application, the quenching adopts a hydrochloric acid solution with a concentration of 4-6%.

[0016] As a further improvement of the present application, the rotation speed of the magnetic stirring is 200~500rpm.

[0017] As a further improvement of the present application, in step S5, the thickness of the quality control samples of the silver impurity series is 0.2-2.0 mm.

[0018] In the second aspect, the present application provides a series of quality control samples of impurities in silver, which are prepared by the preparation method of the series of quality control samples of impurities in silver described in the first aspect, and include 10 impurity elements: Au, Bi, Fe, Pb, Pd, Sb, Se, Te, Cu, and Zn.

[0019] The beneficial effects of this application are:

[0020] The present application provides a series of quality control samples of impurities in silver and a preparation method thereof. The series of quality control samples of impurities in silver are prepared by a step-by-step smelting and quenching process. First, a first group of metals is wrapped with silver sheets and embedded in silver powder. After multi-stage heating and melting under a vacuum environment, a second group of metals is added to melt and cast to obtain a first impurity sample; then the melting and casting process is repeated twice to obtain a second impurity sample and a third impurity sample, respectively; finally, the three samples are subjected to sheet rolling to obtain a series of quality control samples of impurities in silver. In addition to the main element silver, the series of quality control samples of impurities in silver provided in the present application contain 10 elements including gold, bismuth, copper, iron, lead, palladium, antimony, selenium, tellurium, and zinc. These elements include the 8 mandatory impurity elements specified in the GB / T4135 "Silver Ingot" standard, and add gold and zinc, two common impurity elements in high-silver alloys. They can meet the laboratory's needs for quality control of the entire process of high-silver alloy testing.

[0021] The preparation of the quality control samples of the silver impurity series in the present application is as follows: high and low melting point metals are added in batches, the low melting point impurity element metal is wrapped and buried with pure silver, and the volatile zinc is prepared using copper-zinc alloy as raw material. Magnetic stirring is performed during the vacuum melting process to prepare high-content impurity element high-silver alloy samples, and then the samples are diluted with the alloys as raw materials, thereby ensuring that the low content of impurity elements is uniformly and stably melted into the silver, improving the controllability of the impurity element content, and fully ensuring that the prepared quality control samples of the silver impurity series are uniform and reliable.

[0022] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0023] The following embodiments of the technical solution of the present application are described in detail. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusions.

[0025] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0026] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] High-content silver alloys are generally tested using the subtraction method, but sample loss may occur during the sample digestion, transfer, and volume determination process. In addition, the testing instrument itself may also fluctuate, resulting in inaccurate final test results.

[0028] In order to solve the technical problem of low accuracy of the determination results of high-content silver alloys, the present application provides a series of quality control samples of impurities in silver and a preparation method thereof, wherein a series of quality control samples of high-silver alloys containing 10 impurity elements (Au, Bi, Cu, Fe, Pb, Pd, Sb, Se, Te, Zn) are prepared by optimizing the process steps and conditions, and the different impurity elements are set at high, medium and low contents within the specified range to meet the diverse needs of different samples and improve the analysis accuracy of silver alloys.

[0029] In a first aspect, the present invention provides a method for preparing a series of quality control samples of impurities in silver, comprising the following steps:

[0030] S1. Weigh eight impurity metals, brass, and pure silver. The eight impurity metals are Au, Bi, Fe, Pb, Pd, Sb, Se, and Te. Pure silver includes silver flakes and silver powder. Bi, Pb, Sb, Se, Te, and brass are considered the first group of metals, and Au, Fe, and Pd are considered the second group of metals.

[0031] S2. Wrap the first group of metals with silver flakes and place them in a container with silver powder on the bottom, covering the silver powder and burying the inclusions. Place the container in a vacuum environment and preheat the container by heating it at a predetermined rate to a first predetermined temperature. Then, heat it to a second predetermined temperature and hold it for a predetermined time. After all the metals have melted, add the second group of metals and continue heating them to a third predetermined temperature under magnetic stirring. After all the metals have melted, cast them into a preheated mold, solidify, cool, quench, clean, and dry them to obtain a first impurity sample.

[0032] S3. A first impurity sample is intercepted and placed in a container with silver powder on the bottom, and the silver powder is covered to bury the sample; the container is placed in a vacuum environment, and the temperature is raised to a first preset temperature at a predetermined rate to preheat the container. Thereafter, the temperature is raised to a second preset temperature and maintained at this temperature for a predetermined time. The temperature is further raised to a third preset temperature under magnetic stirring. After the metal is completely melted, the metal is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a second impurity sample;

[0033] S4. A second impurity sample is intercepted and placed in a container with silver powder on the bottom, and the silver powder is covered to bury the sample; the container is placed in a vacuum environment, and the temperature is raised to a first preset temperature at a predetermined rate to preheat the container. Thereafter, the temperature is raised to a second preset temperature and maintained at this temperature for a predetermined time. The temperature is further raised to a third preset temperature under magnetic stirring. After the metal is completely melted, the metal is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a third impurity sample;

[0034] S5. The first impurity sample, the second impurity sample, and the third impurity sample are subjected to sheet rolling to obtain a series of quality control samples of impurities in silver.

[0035] In the technical solution of the embodiment of the present application, the mass of each metal is calculated according to the target content and smelting recovery rate set for different elements, and a balance with an appropriate range is used for weighing. The metal elements are grouped according to the melting and boiling points. The impurity metals with a melting point below 1000°C are divided into a first group of metals, including: Bi, Pb, Sb, Se, Te and brass, and the impurity metals with a melting point above 1000°C are divided into a second group of metals, including: Au, Fe, Pd, and introduced at different smelting stages. The proportion and concentration of each component in the final sample can be more accurately controlled; by performing three consecutive smeltings, each time using the sample obtained from the previous smelting as part of the raw material, a series of samples with decreasing impurity concentrations are prepared; the entire smelting process is carried out in a vacuum environment to prevent the impurity elements from being oxygenated by air at high temperatures The method not only reduces the amount of molten silver and impurities in the silver ore, but also prevents gases (such as nitrogen and oxygen) or dust in the air from contaminating the molten silver and impurities, ensuring the accuracy of the sample composition; the staged heating method can better control the melting process of the material and avoid local overheating or incomplete melting; magnetic stirring is performed in the high-temperature molten state to ensure that all components are fully mixed and evenly distributed; casting into a preheated mold can reduce the chilling effect of the melt on the mold wall, which helps to obtain a more uniform solidification structure; solidification, cooling, and quenching help to obtain a dense, relatively uniform block sample, which is convenient for subsequent sheet rolling; the samples obtained from the three smelting processes are sheet rolled to process the block sample into a sheet sample with a specific thickness, a flat surface, and a uniform cross-section, which is convenient for measurement on the analytical instrument, ensuring the consistency of the measurement conditions, and thus improving the efficiency and accuracy of the use of quality control samples.

[0036] Furthermore, in some embodiments, the purity of the impurity element metal and the pure silver is not less than 99.99%.

[0037] In the technical solution of the embodiment of the present application, controlling the purity of impurity element metals and pure silver helps to ensure the accuracy and representativeness of quality control samples, ensure the accuracy of quality control sample composition, reliability of analysis, stability of performance and meet the needs of high-precision analysis.

[0038] Furthermore, in some embodiments, the brass is a copper-zinc alloy with a purity of not less than 99.99%.

[0039] In the technical solution of the embodiments of this application, the total copper and zinc content of the brass exceeds 99.99%, minimizing the introduction of other unknown impurities. This ensures the accuracy, purity, and representativeness of the final silver quality control sample composition, enabling it to meet the requirements for precise and comprehensive quality control of silver materials. Specifically, the copper-to-zinc ratio in the brass is determined based on the copper and zinc content of the desired sample, and an appropriate brass is selected for the experiment.

[0040] Furthermore, in some embodiments, the first preset temperature is 450-550° C., and the heating rate is 15-20° C. / min.

[0041] In the technical solution of the embodiment of the present application, the main purpose of heating to the first preset temperature is to preheat the entire container system. Slow preheating helps to uniformize the temperature inside the system and reduce local stress in the container or sample displacement that may be caused by excessive temperature difference.

[0042] Furthermore, in some embodiments, the second preset temperature is 950-1050° C., and the holding time is 10-20 minutes; the third preset temperature is 1450-1550° C., and the holding time is 1-3 minutes.

[0043] In the technical solution of the embodiment of the present application, the temperature is raised to the second preset temperature mainly to melt the initially added impurity metals and brass, and to cause them to initially dissolve and diffuse with the silver matrix. Insulation helps to alleviate the compositional inhomogeneity caused by the local addition of impurities, so that the first group of impurities is more evenly distributed in the silver matrix; the temperature is raised to the third preset temperature in order to achieve complete melting and homogenization of all components under magnetic stirring, and finally obtain a liquid alloy with uniform composition. Metals are more easily oxidized or volatilized at high temperatures, and a shorter insulation time helps to enter the casting stage as soon as possible after homogenization is completed, thereby reducing the impact of adverse factors.

[0044] Furthermore, in some embodiments, quenching is performed using a hydrochloric acid solution with a concentration of 4-6%.

[0045] In the technical solution of the embodiment of the present application, the use of 4-6% hydrochloric acid solution for quenching can effectively reduce the microstructural changes of the sample and avoid the formation of uneven grains; when the hydrochloric acid concentration is lower than 4%, its cleaning ability may be insufficient and it may not be able to effectively remove surface oxides, resulting in a decrease in the surface quality of the sample; when the hydrochloric acid concentration exceeds 6%, its corrosiveness may increase, which may not only damage the sample surface, but also affect the uniform distribution of the silver matrix and other impurity elements.

[0046] Furthermore, in some embodiments, the rotation speed of the magnetic stirring is 200-500 rpm.

[0047] In the technical solution of the embodiment of the present application, impurity elements are evenly distributed in the silver matrix through magnetic stirring, thereby avoiding component segregation and improving component uniformity. During the stirring process, the melt temperature distribution is more even, avoiding local overheating or overcooling.

[0048] Furthermore, in some embodiments, in step S5, the thickness of the quality control samples of the silver impurity series is 0.2-2.0 mm.

[0049] In the technical solution of the embodiment of the present application, the sample is rolled by a sheet rolling machine to a thickness suitable for shearing with scissors, which is suitable for various detection technologies.

[0050] In the second aspect, an embodiment of the present application provides a series of quality control samples of impurities in silver, which are prepared by the preparation method of the series of quality control samples of impurities in silver described in the first aspect, and include 10 impurity elements: Au, Bi, Fe, Pb, Pd, Sb, Se, Te, Cu, and Zn.

[0051] In the technical solution of the embodiment of the present application, the quality control sample contains common impurity elements and required impurity types in high-silver alloys, providing accurate and reliable quality control standards for the analysis of silver materials, and can be widely used in the laboratory's quality assurance and quality control system.

[0052] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0053] Example

[0054] This embodiment provides a method for preparing a series of quality control samples of impurities in silver, comprising the following steps:

[0055] S1. Calculate the mass of each metal based on the target content and smelting recovery rate set for each element. Weigh eight impurity metals, brass, and pure silver. The eight impurity metals are Au, Bi, Fe, Pb, Pd, Sb, Se, and Te. Pure silver includes silver flakes and silver powder. The metal purity is at least 99.99%. The mass ratio of copper to zinc in brass is 62:38. Impurity metals with a melting point below 1000°C are considered the first group of metals, including Bi, Pb, Sb, Se, Te, and brass. Impurity metals with a melting point above 1000°C are considered the second group of metals, including Au, Fe, and Pd. The target impurity element contents are shown in Table 1.

[0056] S2. After the first group of metals are wrapped with silver sheets, a layer of silver powder is first laid at the bottom of the graphite crucible, and the impurity metal after the wrapping is placed on the silver powder. The remaining silver powder is all added to the crucible, and the silver bag with the impurity metal is completely buried. The graphite crucible is placed in a vacuum melting furnace. After evacuation, the graphite crucible is heated, and the temperature is slowly raised to 500°C at 15°C / min to fully preheat the graphite crucible and the metal in the crucible. Thereafter, the temperature is raised to 1000°C and kept warm for 15min. After all the metals are melted, the second group of metals is added to a sample spoon, and the temperature is continued to be raised to 1500°C and kept warm for 1min under magnetic stirring. After all the metals are melted, the liquid metal is poured into a preheated graphite mold in a vacuum environment. After the metal in the graphite mold solidifies and cools slightly, the vacuum environment is released, the furnace door is opened, and the metal in the mold is quickly removed and placed in a 5% hydrochloric acid solution for quenching. The metal surface is then washed with water and allowed to air dry to obtain a first impurity sample.

[0057] S3. Use hydraulic pliers to intercept the first impurity sample, weigh it accurately, and then weigh an appropriate amount of powdered pure silver. First, spread a layer of silver powder on the bottom of the graphite crucible, then place the intercepted first impurity sample on the silver powder, and add all the remaining silver powder into the crucible to completely bury the sample; place the graphite crucible in a vacuum melting furnace, evacuate the vacuum, heat the graphite crucible, and slowly raise the temperature to 500°C at 15°C / min to fully preheat the graphite crucible and the metal in the crucible. Thereafter, raise the temperature to 1000°C and keep warm for 15 minutes, continue to raise the temperature to 1500°C under magnetic stirring and keep warm for 1 minute. After the metal is completely melted, pour the liquid metal into the preheated graphite mold in a vacuum environment. After the metal in the graphite mold solidifies and cools slightly, release the vacuum environment, open the furnace door, quickly take out the metal in the mold and quench it in 5% hydrochloric acid solution, then wash the metal surface with clean water, and air dry it naturally to obtain a second impurity sample;

[0058] S4. Use hydraulic pliers to intercept the second impurity sample, weigh it accurately, and then weigh an appropriate amount of powdered pure silver. First, spread a layer of silver powder on the bottom of the graphite crucible, then place the intercepted second impurity sample on the silver powder, and add all the remaining silver powder into the crucible to completely bury the sample; place the graphite crucible in a vacuum melting furnace, evacuate the vacuum, heat the graphite crucible, and slowly raise the temperature to 500°C at 15°C / min to fully preheat the graphite crucible and the metal in the crucible. Thereafter, raise the temperature to 1000°C and keep warm for 15 minutes, continue to raise the temperature to 1500°C under magnetic stirring and keep warm for 1 minute. After the metal is completely melted, pour the liquid metal into the preheated graphite mold in a vacuum environment. After the metal in the graphite mold solidifies and cools slightly, release the vacuum environment, open the furnace door, quickly take out the metal in the mold and quench it in 5% hydrochloric acid solution, then wash the metal surface with clean water, and air dry it naturally to obtain a third impurity sample;

[0059] S5. The first impurity sample, the second impurity sample, and the third impurity sample are rolled to 1 mm using a sheet rolling machine to obtain a series of quality control samples of silver impurities.

[0060] According to the requirements of YS / T 958-2014 "Chemical Analysis Methods for Silver", samples were taken from different parts of the prepared samples, digested and then tested using inductively coupled plasma atomic emission spectrometry. The test results of 10 impurity elements, including Au, Bi, Fe, Pb, Pd, Sb, Se, Te, Cu and Zn, in the quality control samples of the silver impurity series are shown in Table 2-11.

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072] From the data in the table, it can be seen that the precision and accuracy of the values ​​of the 10 elements are good, and they can be used for quality control of chemical testing or other purposes.

[0073] Comparative Example

[0074] The comparative example provides a method for preparing a series of quality control samples of impurities in silver, comprising the following steps:

[0075] S1. Select 10 impurity elements (Au, Bi, Cu, Fe, Pb, Pd, Sb, Se, Te, Zn) and pure silver, all of which must be pure metals with a purity of at least 99.99%;

[0076] S2. Calculate the mass of each metal based on the target content and smelting recovery set for each element, as shown in Table 12, using a balance with an appropriate range;

[0077] S3. Impurity metals with a melting point below 1000°C are classified into a first group of metals, including Bi, Pb, Sb, Se, Te, and Zn; impurity metals with a melting point above 1000°C are classified into a second group of metals, including Au, Cu, Fe, and Pd;

[0078] S4. Weigh the pure silver powder raw material and spread a layer of silver powder on the bottom of a graphite crucible. Then place the first group of metals on the silver powder. Add all the remaining silver powder to the crucible to completely bury the impurity metals. Place the graphite crucible in a vacuum melting furnace and place the second group of metals in a sample spoon.

[0079] S5. After evacuating the vacuum melting furnace, heat the graphite crucible and slowly increase the temperature to 500°C at a rate of 15°C / min to fully preheat the graphite crucible and the metal in the crucible. Then continue heating to 1000°C and hold for 15 minutes. Once the metal is completely melted, add the metal from the sample spoon to the crucible. Turn on magnetic stirring and continue heating to 1500°C and hold for 1 minute until the metal in the crucible is completely melted. Then, pour the liquid metal into the preheated graphite mold in a vacuum environment.

[0080] S6. After the metal in the ink mold solidifies and cools slightly, release the vacuum environment, open the furnace door, quickly remove the metal from the mold, and quench it in a 5% hydrochloric acid solution. Then, rinse the metal surface with clean water and air-dry it to obtain a quality control sample of silver impurities.

[0081] During the smelting process in step S5, a large amount of smoke was produced, and the volatilization of low-boiling-point metallic elements could not be effectively controlled. After sample preparation, according to the requirements of YS / T 958-2014 "Chemical Analysis Methods for Silver," samples were taken from different locations, digested, and analyzed using inductively coupled plasma atomic emission spectrometry. The results are shown in Table 13.

[0082]

[0083]

[0084] It can be seen from the data in the table that due to improper preparation methods, some impurity metal elements have seriously volatilized, resulting in uncontrollable values ​​and failure to meet expected requirements.

[0085] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a series of quality control samples of impurities in silver, characterized in that: The following steps are involved: S1. Weigh eight impurity metal elements, brass, and pure silver, respectively. The eight impurity metal elements are Au, Bi, Fe, Pb, Pd, Sb, Se, and Te; the pure silver includes silver flakes and silver powder; Bi, Pb, Sb, Se, Te, and brass are considered as the first group of metals, and Au, Fe, and Pd are considered as the second group of metals; S2. Wrap the first group of metals with silver sheets and place them in a container with silver powder on the bottom, covering the silver powder and burying the inclusions; place the container in a vacuum environment, and preheat the container by heating it at a predetermined rate to a first predetermined temperature. Thereafter, heat it to a second predetermined temperature and maintain it for a predetermined time. After all the metals have melted, add the second group of metals, continue heating it to a third predetermined temperature under magnetic stirring, and after all the metals have melted, cast it into a preheated mold, solidify it, cool it, quench it, clean it, and dry it to obtain a first impurity sample; S3. intercepting the first impurity sample and placing it in a container with silver powder on the bottom, covering the sample with the silver powder; placing the container in a vacuum environment, heating the container at a predetermined rate to a first preset temperature to preheat the container, then heating the container to a second preset temperature and holding the temperature for a predetermined time, and then heating the container to a third preset temperature under magnetic stirring. After the metal is completely melted, the container is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a second impurity sample; S4. intercepting the second impurity sample, placing it in a container with silver powder on the bottom, covering the sample with the silver powder; placing the container in a vacuum environment, heating it to a first preset temperature at a predetermined rate to preheat the container, then heating it to a second preset temperature and holding it for a predetermined time, and then heating it to a third preset temperature under magnetic stirring. After the metal is completely melted, the container is cast into a preheated mold, solidified, cooled, quenched, cleaned, and dried to obtain a third impurity sample; S5. The first impurity sample, the second impurity sample, and the third impurity sample are subjected to sheet rolling to obtain a series of quality control samples of silver impurities.

2. The method for preparing a series of quality control samples of silver impurities according to claim 1, wherein In step S1, the purity of the impurity element metal and pure silver is not less than 99.99%.

3. The method for preparing a series of quality control samples of silver impurities according to claim 2, wherein: The brass is a copper-zinc alloy with a purity of not less than 99.99%.

4. The method for preparing a series of quality control samples of impurities in silver according to claim 1, wherein The first preset temperature is 450-550°C, and the heating rate is 15-20°C / min.

5. The method for preparing a series of quality control samples of silver impurities according to claim 1, wherein The second preset temperature is 950-1050° C., and the holding time is 10-20 minutes; the third preset temperature is 1450-1550° C., and the holding time is 1-3 minutes.

6. The method for preparing a series of quality control samples of silver impurities according to claim 1, wherein: The quenching is performed using a hydrochloric acid solution with a concentration of 4-6%.

7. The method for preparing a series of quality control samples of silver impurities according to claim 1, wherein: The rotation speed of the magnetic stirring is 200-500 rpm.

8. The method for preparing a series of quality control samples of impurities in silver according to claim 1, wherein: In step S5, the thickness of the silver impurity series quality control samples is 0.2-2.0 mm.

9. A series of quality control samples of impurities in silver, characterized in that: The silver impurity series quality control sample is prepared by the preparation method of any one of claims 1 to 8, comprising 10 impurity elements: Au, Bi, Fe, Pb, Pd, Sb, Se, Te, Cu, and Zn.

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