Preparation method of platinum solid standard substance or platinum alloy standard substance containing impurity elements

Abstract

The invention provides a preparation method of a platinum solid standard substance or a platinum alloy solid standard substance containing impurity elements. The preparation method comprises the following steps: S1) preparing a platinum base material containing impurities; s2) melting platinum, preserving heat, vacuumizing, and cooling to obtain a refined material; s3) heating the refined material, preserving the heat, vacuumizing while preserving the heat, and adding a platinum base material for atomizing and pulverizing to obtain a powder material; s4) sintering the powder material, and then molding; s5) carrying out hot forging on the obtained platinum ingot, and then sequentially carrying out cold rolling and heat treatment; and S6) carrying out homogenization heat treatment on the obtained initial substance to obtain the platinum solid standard substance. By designing the preparation method of the platinum solid standard substance, the distribution uniformity of impurity elements of the standard substance in a matrix is remarkably improved, and the platinum solid standard substance can be used for establishing or calibrating an impurity element standard curve by an X-fluorescence and spark direct-reading spectrometer so as to improve the accuracy of a detection analysis result.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of standard samples, and particularly relates to a method for preparing a platinum solid reference material or a platinum alloy solid reference material containing impurity elements. Background Art

[0002] In the glass and glass fiber industries, platinum or platinum-rhodium alloy is widely used due to its excellent physical and chemical properties. Especially its high melting point, good oxidation resistance and corrosion resistance make it the most ideal functional material and high-temperature structural material used in the glass and glass fiber forming processes. Platinum or platinum-rhodium alloy is used to make the inner lining of containers for molten glass, conveying pipelines, ceramic stirrers for mixing molten glass and other equipment to ensure high-quality glass production; at the same time, it is widely used in the glass fiber industry to make key devices for wire drawing and forming such as bushings, thermocouple sleeves, baffle bricks and bubbling tubes, playing a very important role.

[0003] During the processing and use of platinum or platinum-rhodium alloy products, they will be contaminated by the surrounding contacting materials, resulting in the excessive impurity content in platinum or platinum-rhodium alloy after use. The raw materials with excessive impurities must be purified before use. Detection shows that the main impurity elements that are likely to contaminate platinum or platinum-rhodium alloy devices include more than ten elements such as iron (Fe), silicon (Si), aluminum (Al), copper (Cu), magnesium (Mg), chromium (Cr), nickel (Ni), manganese (Mn), cadmium (Cd), bismuth (Bi), lead (Pb), zinc (Zn) and tin (Sn). At present, ICP-OES or ICP-MS wet chemical analysis is used to detect the impurity content in platinum or platinum-rhodium alloy. Although this method has the advantage of obtaining certified reference materials, the sample preparation process of this method is long and time-consuming, dilution will reduce the sensitivity, and increase the risk of environmental pollution. During the purification process of platinum or platinum-rhodium alloy raw materials, wet chemical analysis methods are generally used to determine the impurity content in the raw materials; rarely are X-ray fluorescence or spark direct reading spectrometers used to detect and analyze the impurity content in the raw materials.

[0004] Usually, ICP chemical analysis method is used to determine the impurity content in platinum or platinum-rhodium alloy raw materials. The advantages of using chemical analysis method are: high detection and analysis accuracy, and can detect trace impurity content in raw materials; wide sampling area (usually the sampling amount is 0.2 - 0.5g), and the impurity element content in the sample can be accurately detected; the disadvantages are that the sample preparation process is cumbersome and time-consuming. When using X-ray fluorescence or spark direct reading spectrometers for analysis, since the content of each impurity element in the raw materials is low, the accuracy and accuracy of the detection results are not as good as ICP, but the latter has the advantages of convenient and fast sample preparation and fast detection speed. However, currently, the reference materials for X-ray fluorescence or spark direct reading instruments are missing, or there are reference materials but the impurity content distribution in the reference materials is uneven; resulting in deviation from the true results when establishing the impurity element standard curve, and the results of the detected substances are distorted.

[0005] Therefore, it is of great significance to provide a preparation method of a platinum or platinum alloy solid reference material to improve the distribution of impurity elements in the matrix and ultimately improve the accuracy of detection and analysis results. Summary of the Invention

[0006] The technical problem solved by the present invention lies in providing a preparation method of a platinum solid reference material or a platinum alloy solid reference material containing impurity elements, which can improve the compositional uniformity and stability of the platinum solid reference material or the platinum alloy solid reference material containing impurities.

[0007] In view of this, the present application provides a preparation method of a platinum solid reference material or a platinum alloy solid reference material containing impurity elements, comprising the following steps:

[0008] S1) Refine the first pure platinum and then add the first impurity metal, and melt to obtain the first platinum base material; the first pure platinum includes the first pure platinum or the first platinum alloy, and the first impurity metal includes one or more of Bi, Pb, As, and Sn;

[0009] Melt the second impurity metal and the second pure platinum to obtain the second platinum base material; the second pure platinum includes the second pure platinum or the second platinum alloy, and the second impurity metal includes one or more of Fe, Cu, Ni, Mo, Co, Mn, Cr, Mg, Ca, Al, Si, and Zn;

[0010] S2) Melt pure platinum or a pure platinum alloy and keep it warm. While keeping it warm, evacuate the air, and then cool it. Repeat the above steps at least twice to obtain the refined material;

[0011] S3) Heat the refined material and keep it warm. While keeping it warm, evacuate the air, and then add the first platinum base material and the second platinum base material for atomization powder making to obtain a powder material;

[0012] S4) Sinter the powder material and then form it;

[0013] S5) Hot forge the platinum ingot obtained in step S4), and then perform cold rolling and heat treatment in sequence, and repeat cold rolling and heat treatment multiple times;

[0014] S6) Perform homogenization heat treatment on the initial material obtained in step S5) to obtain a platinum solid reference material or a platinum alloy solid reference material.

[0015] In some specific embodiments, in step S1), in the step of obtaining the first platinum base material, the melting temperature is 1700 - 1900 °C, and in the step of obtaining the second platinum base material, the melting temperature is 1700 - 1900 °C;

[0016] And / or, the first platinum alloy includes a platinum-rhodium alloy, a platinum-palladium alloy or a platinum-rhodium-palladium alloy;

[0017] And / or, the second platinum alloy includes a platinum-rhodium alloy, a platinum-palladium alloy or a platinum-rhodium-palladium alloy.

[0018] In some specific embodiments, in step S2), the melting temperature is 50-100°C above the melting point of pure platinum or a pure platinum alloy, the holding time is 10-20 min, and the degree of vacuum for evacuation is below 10 Pa.

[0019] In some specific embodiments, in step S2), stirring is performed during the holding process, and the stirring includes electromagnetic induction heating stirring and mechanical stirring.

[0020] In some specific embodiments, in step S3), the heating temperature is 50-100°C above the melting point of the refined material, the degree of vacuum for evacuation is below 10 Pa, and the holding time is 10-20 min.

[0021] In some specific embodiments, before adding the first platinum base material and the second platinum base material in step S3), it further includes:

[0022] Raising the temperature of the melt after holding to 150-200°C above the melting point;

[0023] After adding the first platinum base material and the second platinum base material, it further includes holding, and the holding time is 5-10 min.

[0024] In some specific embodiments, the atomization powder making is specifically:

[0025] Injecting high-purity argon gas into the furnace body;

[0026] Starting the high-pressure atomization powder making equipment, injecting the melt after holding into the tundish crucible, and the melt flows through the tundish crucible into the atomization channel for atomization powder making;

[0027] And / or, the medium for atomization powder making is high-purity deionized water, the temperature of the medium is 0-10°C, the pressure for atomization powder making is 50-100 MPa, the flow rate of the medium for atomization powder making is 50-150 L / min, the diameter of the tundish crucible leakage hole for atomization powder making is 3-10 mm, and the atomization cylinder wall for atomization powder making is cooled by sandwich water, and the temperature of the sandwich water is 0-10°C.

[0028] In some specific embodiments, in step S4), the sintering process is specifically:

[0029] Heat the powder material from room temperature to 800 - 900 °C at a rate of 5 - 10 °C / min, hold for 300 - 400 min, then heat to 1200 - 1300 °C at a rate of 10 - 15 °C / min, hold for 60 - 80 min, and finally cool with the furnace;

[0030] And / or, the sintering is carried out in vacuum sintering;

[0031] And / or, the forming includes pre - pressing and re - pressing carried out in sequence. The pressure of the pre - pressing is 200 - 300 MPa, and the pressure of the re - pressing is 400 - 500 MPa; An annealing treatment is also included between the pre - pressing and the re - pressing. The temperature of the annealing treatment is 1000 - 1200 °C, and the time is 50 - 100 min.

[0032] In some specific embodiments, in step S5), the temperature of the hot forging is 1000 - 1500 °C, the number of hot forging times is at least 1 time, and the density of the platinum ingot after hot forging is not less than 99.5% of the theoretical density;

[0033] And / or, the deformation amount of the cold rolling is greater than 200%;

[0034] And / or, the temperature of the heat treatment is 1300 - 1400 °C, the time is 30 - 60 min, and the heat treatment is carried out in an inert atmosphere;

[0035] And / or, the thickness of the platinum ingot after being repeated multiple times is 1.5 - 3.5 mm.

[0036] In some specific embodiments, in step S6), the temperature of the homogenization heat treatment is 1300 - 1500 °C, and the time is 50 - 60 h.

[0037] The present application provides a method for preparing a platinum solid reference material or a platinum alloy solid reference material containing impurity elements. Firstly, a first platinum base material containing low-melting-point impurities and a second platinum base material containing other impurities are respectively prepared. Then, a pure platinum refining material or a pure platinum alloy refining material is prepared. Next, the refining material, the first platinum base material, and the second platinum base material are mixed and atomized to form a powder material. After that, the powder material is sintered, formed, hot-forged, and subjected to multiple cold rolling and heat treatments. Finally, homogenization heat treatment is carried out to obtain a platinum solid reference material containing impurity elements or a platinum alloy reference material containing impurity elements. During the preparation process of the platinum solid reference material or the platinum alloy solid reference material containing impurity elements, firstly, pure platinum or pure platinum alloy is initially refined multiple times, which is beneficial to improving the uniformity of the composition. At the same time, the powder material is prepared by the rapid cooling method of atomization powdering, and combined with the powder sintering process, a platinum sintered material containing impurities or a platinum alloy sintered material containing impurities is prepared, controlling the composition segregation generated during the cooling and solidification process of the sintered material. Finally, the intragranular segregation is eliminated through homogenization treatment, significantly improving the accuracy, uniformity, and stability of the composition of the platinum reference material containing impurities or the platinum alloy reference material containing impurities.

[0038] Furthermore, during the batching process, the addition amount of raw materials is reasonably controlled according to different forms of raw material addition. During the refining process, the combined action of mechanical stirring and electromagnetic stirring makes the temperature inside the melt more uniform, ensuring the uniform distribution of impurity elements in the platinum melt, and finally improving the uniformity and stability of the platinum solid reference material or the platinum alloy solid material containing impurity elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic flow chart of the preparation of the platinum solid reference material or the platinum alloy solid reference material containing impurity elements of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0041] Platinum or platinum alloys used for glass and glass fiber will be contaminated with impurity elements during the processing and use. In order to improve the accuracy of detection and analysis results, the present application provides a preparation method for a platinum solid reference material containing impurity elements or a platinum alloy solid reference material containing impurity elements, which can prepare a reference material with stable components, uniform composition, and low segregation of impurity elements. This reference material can be used as a reference material for rapid detection analyzers such as X-ray fluorescence spectrometers, spark direct-reading spectrometers, and micro-electron probe analyzers, for establishing and calibrating the standard curves of detection instruments. After establishing the standard curve, the content of impurity elements in platinum or platinum alloys can be rapidly detected and analyzed; the preparation process of the platinum solid reference material or platinum alloy reference material containing impurity elements in the present application is as Figure 1 shown, which includes component design - preparation of base material - induction refining - atomization powder making - drying and screening - powder sintering - pressing into shape - hot forging - cold rolling / heat treatment (repeatedly) - uniform heat treatment and subsequent grinding and polishing of the reference sample - reference sample value determination - establishment of the standard curve; specifically, the embodiments of the present invention disclose a preparation method for a platinum solid reference material containing impurity elements or a platinum alloy solid reference material containing impurity elements, including the following steps:

[0042] S1) Refine the first pure platinum and then add the first impurity metal, and melt to obtain the first platinum base material; the first pure platinum includes the first pure platinum or the first platinum alloy, and the first impurity metal includes one or more of Bi, Pb, As, and Sn;

[0043] Melt the second impurity metal and the second pure platinum to obtain the second platinum base material; the second pure platinum includes the second pure platinum or the second platinum alloy, and the second impurity metal includes one or more of Fe, Cu, Ni, Mo, Co, Mn, Cr, Mg, Ca, Al, Si, and Zn;

[0044] S2) Melt pure platinum or pure platinum alloy and keep it warm, evacuate the air while keeping it warm, and then cool. Repeat the above steps at least twice to obtain the refined material;

[0045] S3) Heat the refined material and keep it warm, evacuate the air while keeping it warm, and then add the first platinum base material and the second platinum base material for atomization powder making to obtain the powder material;

[0046] S4) Sinter the powder material and then form it;

[0047] S5) Hot forge the ingot obtained in step S4), and then perform cold rolling and heat treatment in sequence, and cold rolling and heat treatment are repeated multiple times;

[0048] S6) Perform homogenization heat treatment on the initial material obtained in step S5) to obtain a platinum solid reference material or a platinum alloy solid reference material.

[0049] In the method for providing a platinum solid reference material or a platinum alloy solid reference material containing impurity elements provided in the present application, the platinum solid reference material is specifically a solid reference material mainly composed of platinum and containing trace impurity elements, and the platinum alloy solid reference material is specifically a solid reference material mainly composed of platinum, containing other precious metals such as palladium, rhodium and other elements, and containing trace impurity elements. For example, a platinum-rhodium alloy containing impurity elements, a platinum-palladium alloy containing impurity elements, or a platinum-rhodium-palladium ternary alloy containing impurity elements; the above-mentioned impurity elements are selected from one or more of iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), aluminum (Al), silicon (Si), magnesium (Mg), calcium (Ca), zinc (Zn), bismuth (Bi), lead (Pb), arsenic (As) and tin (Sn). In specific embodiments, the solid reference material prepared in the present application simultaneously includes the above-mentioned iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), aluminum (Al), silicon (Si), magnesium (Mg), calcium (Ca), zinc (Zn), bismuth (Bi), lead (Pb), arsenic (As) and tin (Sn).

[0050] According to the easily contaminated elements of platinum products or platinum alloy products for glass or glass fiber, a platinum solid reference material containing impurity elements or a platinum alloy solid reference material containing impurity elements is designed. In some specific embodiments, in the platinum solid reference material or platinum alloy solid reference material, the content of impurity element Fe is 0-1000 ppm, and the content of other impurity elements is 0-500 ppm. Specifically, the content of impurity element Fe is 20-800 ppm. More specifically, the content of impurity element Fe is 100-600 ppm. More specifically, the content of impurity element Fe is 160-300 ppm, and the content of other impurity elements is 0-500 ppm. Specifically, the content of other impurity elements is 20-400 ppm. More specifically, the content of other impurity elements is 50-300 ppm. More specifically, the content of other impurity elements is 100-200 ppm. According to the easily contaminated impurity elements of platinum products for glass, and combining historical detection data, the concentration range of impurity elements is reasonably configured; and the platinum base material containing impurities is melted according to the characteristics of the impurity elements. In the present application, preferably according to the burning loss and volatilization degree of the impurity elements during the melting process, the easily burned low-melting metals are melted with pure platinum or platinum alloy to prepare a platinum base material with a high impurity content or a platinum alloy base material with a high impurity content; the remaining impurity elements are melted together with platinum or platinum alloy to prepare a platinum base material with a high impurity content or a platinum alloy base material with a high impurity content.

[0051] The vacuum medium frequency induction heating method is adopted to melt the base material of platinum containing low melting point metals or the base material of platinum alloy containing low melting point metals. Taking the base material of platinum containing low melting point metals as an example, Pt-Bi, Pt-Pb, Pt-As and Pt-Sn alloys are melted. Specifically: first, pure platinum or platinum alloy meeting the purity requirements is placed in an induction furnace for two refinings. The low melting point metals Bi, Pb, As and Sn are added to the platinum melt or platinum alloy melt by the secondary feeding method. After melting, the platinum melt or platinum alloy melt containing impurities is cast and cooled; the temperature of the refining is 1700-1900, more specifically, the temperature of the refining is 1780-1820 °C; during the refining process, the vacuum is first pumped (the vacuum degree is controlled below 10 Pa), and then argon is filled (the air pressure needs to be slightly higher than the atmospheric pressure).

[0052] Then, the vacuum medium frequency induction heating method is adopted to melt the platinum base material containing other impurity metals or the platinum alloy base material containing other impurity metals. The other impurity metals include one or more of iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), magnesium (Mg), calcium (Ca), aluminum (Al), silicon (Si) and zinc (Zn). In a specific embodiment, the other impurity metals include iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), magnesium (Mg), calcium (Ca), aluminum (Al), silicon (Si) and zinc (Zn); taking the platinum base material containing other impurity metals as an example, specifically, Pt-Fe, Pt-Cu, Pt-Ni, Pt-Mo, Pt-Co, Pt-Mn, Pt-Cr, Pt-Mg, Pt-Ca, Pt-Al, Pt-Si and Pt-Zn base materials. The preparation method of the above platinum base material or platinum alloy base material is specifically: first, pure platinum or platinum alloy meeting the purity requirements and impurity elements are added into a zirconia crucible at the same time for two refinings. After refining, the alloy melt is poured and cooled; the temperature of the refining is 1700-1900 °C, specifically, the temperature of the refining is 1830-1870 °C; during the refining process, the vacuum is first pumped (the vacuum degree is controlled below 10 Pa), and then argon is filled (the air pressure needs to be slightly higher than the atmospheric pressure). The above platinum alloy is specifically a platinum-palladium alloy, a platinum-rhodium alloy or a platinum-rhodium-palladium alloy.

[0053] According to the present invention, it is preferred to perform surface milling, rolling, pickling and annealing treatments on the obtained platinum base material or platinum alloy base material; the specific operation means of the milling and the rolling are well-known technical means to those skilled in the art, and this application does not make special restrictions on this; the rolling is to roll the platinum base material or platinum alloy base material into a thin sheet with a thickness of 0.2±0.05 mm, the pickling is to remove the surface contamination caused during the cold working process of the above thin sheet, and the annealing is to facilitate the subsequent folding and cutting of the thin sheet.

[0054] Take the wafer after pickling annealing mentioned above, and use ICP-OES or ICP-MS wet analysis to determine the content of impurity elements in the platinum base material or platinum alloy base material containing impurities, which is convenient for introducing the standard sample preparation of the platinum base material or platinum alloy base material containing impurities and ensuring the accuracy of the impurity element content.

[0055] In this application, pure platinum or pure platinum alloy is then melted and kept warm. While keeping warm, vacuum is pumped, and then it is cooled. The above melting-keeping warm / vacuum pumping-cooling process is repeated at least twice to obtain refined materials. The above process is specifically carried out in an intermediate frequency induction melting furnace, which specifically includes the following steps:

[0056] 1) Take a new ZrO2 crucible, soak it in a 13% hydrochloric acid solution, boil for 20 min to 30 min, and control the solution temperature at 80°C to 100°C;

[0057] 2) Dry / pour the ZrO2 crucible to remove refractory material impurities on the inner wall;

[0058] 3) Place the weighed pure platinum material meeting the purity requirement (≥99.99 wt%) or platinum alloy material meeting the element content in the ZrO2 crucible, and inductively heat the above materials. After the materials are melted, keep the melt temperature 50°C to 100°C above the melting point and keep warm for 10 min to 20 min; during the heat preservation period, at the same time, evacuate the furnace body, and keep the vacuum degree below 10 Pa; after the heat preservation ends, stop heating and let the melt cool naturally in the crucible; during the heat preservation process, in addition to being stirred by electromagnetic induction heating itself, the melt is also stirred by a mechanical stirring device to improve the uniformity of the melt composition;

[0059] 4) When the melt is completely solidified, start inductively heating and melting the metal again, and repeat the above steps twice, that is, "inductive heating and melting → vacuum pumping / heat preservation → natural furnace cooling and solidification." for three times.

[0060] In this application, the above refined materials are then atomized to make powder. In order to achieve rapid cooling powder making, before atomizing the powder, it also includes inductively heating and melting the refined materials again while keeping warm, which specifically includes the following steps:

[0061] 1) Inductively heat the above-mentioned secondary refined materials again to make them melt. After melting, keep the melt temperature between 50°C and 100°C above the melting point, keep warm for 10 min to 20 min, and evacuate the furnace body while keeping warm, and keep the vacuum degree below 10 Pa;

[0062] 2) After the heat preservation time ends, raise the melt temperature to 150°C - 200°C above the melting point; add the first platinum base material or the second platinum base material prepared above into the molten pool for the second time, and keep it warm for 5 min - 10 min. At the same time, inject high-purity argon into the furnace body to make the pressure in the furnace higher than the atmospheric pressure, so as to open the atomization channel valve;

[0063] 3) Start the high-pressure atomization powder-making equipment, and inject the refined platinum melt containing impurities into the tundish crucible. The melt flows into the atomization channel through the tundish crucible, and the platinum melt is instantly broken into powders by high-pressure atomized water to obtain powder materials;

[0064] In the step of atomization powder making, the atomization medium is high-purity deionized water, the temperature of the atomization medium is 0°C - 10°C. Specifically, the temperature of the atomization medium is 2 - 5°C, the atomization pressure is 50 MPa - 100 MPa. Specifically, the atomization pressure is 60 - 80 MPa, the flow rate of the atomization medium is 70 L / min - 150 L / min. Specifically, the flow rate of the atomization medium is 75 - 120 L / min, and the diameter of the leakage hole of the tundish crucible is 3 mm - 8 mm. Specifically, the diameter of the leakage hole of the tundish crucible is 4 - 5 mm;

[0065] The whole atomization cylinder needs to be evacuated first and then filled with inert gas to prevent impurity elements from being oxidized during the atomization powder-making process; the atomization cylinder wall is cooled by water in the interlayer, and the temperature of the cold water in the interlayer is 0°C - 10°C. Specifically, the temperature of the cold water in the interlayer is 2 - 5°C; the tundish crucible uses electromagnetic induction to stir, heat and keep warm the melt.

[0066] This application preferably dries and screens the powder materials obtained above in sequence. The temperature of the drying is 100°C - 150°C. Specifically, the temperature of the drying is 120 - 140°C, the time of the drying is 10 h - 15 h. Specifically, the time of the drying is 11 - 13 h. The screening preferably uses a 200-mesh sieve to screen, so as to collect the powders below 200 meshes and flow into the next process.

[0067] According to the present invention, then sinter the powder materials and then carry out forming. The sintering is carried out in a vacuum sintering atmosphere furnace. The specific sintering process is: start from room temperature and heat up to 800°C - 900°C at a rate of 5°C - 10°C / min, keep warm at 800°C - 900°C for 300 min - 400 min, and then heat up to 1200°C - 1300°C at a heating rate of 10°C - 15°C / min, and keep warm for 60 min - 80 min; finally cool down with the furnace. During the sintering process, the furnace is evacuated and then filled with argon to prevent impurity elements from oxidizing and volatilizing.

[0068] This application then compresses the sintered platinum material containing impurities into a molded shape. The compression molding includes pre-pressing and re-pressing carried out in sequence. Specifically, the pressure of the pre-pressing is 250 MPa to 300 MPa. More specifically, the pressure of the pre-pressing is 260 to 280 MPa. After the pre-pressing, the molded body is placed in a vacuum atmosphere furnace for annealing treatment. The annealing temperature is 1000 °C to 1200 °C, and the time is 50 min to 100 min. Specifically, the annealing temperature is 1050 to 1150 °C, and the time is 60 to 80 min. Before the annealing treatment, the furnace chamber is evacuated first, and then an inert gas is introduced before heating can start. After the annealing, re-pressing is carried out. The pressure of the re-pressing is 450 MPa to 500 MPa. Specifically, the pressure of the re-pressing is 470 to 490 MPa.

[0069] This application then hot-forges the compression-molded platinum material to further increase the density of the platinum material and eliminate internal defects. The temperature of the hot-forging is 1100 °C to 1400 °C. Specifically, the temperature of the hot-forging is 1150 to 1300 °C. In some embodiments, the hot-forging is carried out multiple times. After the hot-forging is completed, the density of the platinum material is tested, and its actual density value is not lower than 99.5% of the theoretical density.

[0070] According to the present invention, the hot-forged platinum material is then cold-rolled and heat-treated in sequence. The deformation amount of the cold-rolling is controlled above 200%. The temperature of the heat treatment is 1300 °C to 1350 °C, and the time is 40 min to 60 min. Before the heat treatment, the vacuum is evacuated first, and then an inert gas is filled. After reaching the annealing time, the platinum sheet is quickly taken out and placed in ice water for rapid cooling. Such cold-rolling and heat-treatment are repeatedly operated until the platinum sheet is rolled to 1.5 mm to 3.5 mm. In this application, it is preferred to mill the upper and lower surfaces of the hot-forged platinum ingot before cold-rolling to remove the surface contamination caused by hot-forging, rolling and other processes. The milling depth is 2 mm to 3 mm.

[0071] According to the requirements of the detection analyzer for the standard sample size, a mold of the corresponding size is selected to blank the platinum reference material. Generally, a mold with a diameter of 30.5 mm is used to blank the standard sample, and a standard substance sample with a diameter of 30 mm is obtained. At the same time, samples are taken around the mother material of the blanked standard sample substance for subsequent ICP detection and analysis to calibrate the element content in the standard substance.

[0072] This application finally places the blanked standard substance in a platinum-rhodium alloy annealing pan and places it in a vacuum atmosphere furnace for homogenization annealing treatment. The temperature of the homogenization annealing treatment is 1300 °C to 1500 °C, and the time is 50 h to 60 h. When the specified holding time is reached, the sample is quickly taken out and placed in cold water at 5 °C for rapid cooling.

[0073] After completing the above steps, the present application realizes the preparation of a platinum solid reference material containing impurity elements or a platinum alloy standard solid containing impurity elements. The subsequent steps are to perform composition detection on the platinum solid reference material containing impurity elements or the platinum alloy standard solid containing impurity elements, including grinding and polishing - standard sample value determination - standard establishment in sequence.

[0074] Among them, the grinding and polishing specifically is: pickling the platinum solid reference material or platinum alloy standard solid after homogenization heat treatment. The pickling is to place the reference material in a beaker containing 13% dilute hydrochloric acid, heat it to 80 °C and keep it warm for 60 min to eliminate the residual impurity elements on the surface of the reference material. After pickling the reference material, use a grinding and polishing machine to perform grinding and polishing treatment on the upper and lower surfaces of the reference material until a mirror surface is polished.

[0075] The standard sample value determination includes ICP - OES chemical value determination and reference material homogeneity detection; among them, the ICP - OES chemical value determination specifically is:

[0076] Conduct chemical value determination and analysis on the samples taken around the standard sample base material according to relevant standards. Select different base materials for each mass fraction sample piece, cut and mix them evenly, weigh a certain mass of the sample, digest it with aqua regia by high - pressure microwave digestion, then transfer it to a volumetric flask of a certain volume and make up the volume with deionized water. Test the impurity element standard solution and the standard sample solution on an ICP - OES spectrometer, determine the mass concentration of the impurity elements, and then determine the mass fraction of the impurity elements according to relevant methods.

[0077] The reference material homogeneity detection specifically is:

[0078] Randomly select the prepared reference material sample pieces, conduct homogeneity inspection on the standard sample pieces of each mass fraction, and perform non - destructive testing on the platinum reference material containing impurities or the platinum alloy reference material containing impurities using an X - ray fluorescence spectrometer according to the requirements of the national standard reference material homogeneity inspection.

[0079] Furthermore, perform multiple non - destructive tests on different regions of the same reference material using an X - ray fluorescence spectrometer to evaluate the homogeneity of the platinum component distribution of the same sample piece. According to the above - mentioned test and analysis results, determine the value of the prepared platinum reference material containing impurities or the platinum alloy reference material containing impurities.

[0080] The standard establishment specifically is: use the prepared reference material to test on an X - ray fluorescence spectrometer, a spark direct - reading spectrometer or an electron probe instrument to establish a standard curve.

[0081] In the present application, the platinum - gold does not mean an alloy containing platinum element and gold element, but means pure platinum or a platinum alloy. Among them, the platinum alloy means a platinum - palladium alloy, a platinum - rhodium alloy or a platinum - palladium - rhodium alloy.

[0082] The present invention provides a method for preparing a platinum solid reference material or a platinum alloy solid reference material containing impurity elements. By the combined action of mechanical stirring and electromagnetic stirring during the refining process of platinum containing impurities, the distribution of impurity elements in the original platinum melt containing impurities is ensured to be uniform. Further, a rapid cooling method is adopted to prepare a platinum powder material containing impurities, and then a platinum reference material containing impurities is prepared through powder metallurgy technology. The composition segregation generated during the cooling and solidification of the platinum containing impurities is controlled, and homogenization heat treatment is used to eliminate the segregation within the crystal, significantly improving the stability and uniformity of the composition of the platinum reference material containing impurities. The method for preparing the reference material provided in this application can achieve rapid detection of impurity elements, avoiding the problems of time-consuming, long cycle, and reduced metal turnover rate in the past when the ICP-OES method was required.

[0083] To further understand the present invention, the following examples are used to illustrate in detail the method for preparing a platinum solid reference material or a platinum alloy solid reference material containing impurity elements provided by the present invention. The protection scope of the present invention is not limited by the following examples.

[0084] Examples

[0085] 1) Design of the composition of the reference material containing impurities

[0086] According to the impurity elements that are easily contaminated in platinum products for glass or glass fiber, the composition of the platinum solid reference material containing impurities is designed. Its impurity elements include 13 impurity elements such as iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), aluminum (Al), silicon (Si), magnesium (Mg), calcium (Ca), zinc (Zn), and tin (Sn);

[0087] Among the above impurity elements, the detection concentration range of the Fe element is required to be 0 - 1000 ppm, and the concentration detection concentration range of the remaining impurity elements is required to be 0 - 500 ppm;

[0088] According to the interference factors of the detection peaks of impurity element atomic emission spectra, the compositions of five reference materials are designed in this example, as shown in Table 1.

[0089] 2) Preparation of the platinum base material containing impurities by batching

[0090] The platinum base material containing low melting point metals is melted by a vacuum medium frequency induction heating method, including Pt-Bi, Pt-Pb, Pt-As, and Pt-Sn alloys respectively. Specifically: first, pure platinum meeting the purity requirements is placed in an induction furnace for two refinings, and the low melting point metals Bi, Pb, As, and Sn are added to the platinum melt by a secondary feeding method. After melting, the platinum melt containing impurities is cast and cooled, and the melting temperature is maintained at 1800 °C. During the melting process, the vacuum is pumped according to the conventional process (the vacuum degree is controlled below 10 Pa), and argon is filled (the air pressure needs to be slightly higher than the atmospheric pressure);

[0091] The platinum base material containing other impurity metals is melted by means of intermediate frequency induction heating in vacuum, including Pt-Fe, Pt-Cu, Pt-Ni, Pt-Mo, Pt-Co, Pt-Mn, Pt-Cr, Pt-Mg, Pt-Ca, Pt-Al, Pt-Si and Pt-Zn alloy base materials. Specifically: First, pure platinum meeting the purity requirements and other impurity elements are simultaneously added into a zirconia crucible, and two refinings are carried out. After refining, the alloy melt is poured and cooled, and the melting temperature is maintained at 1850 °C. During the melting process, vacuum is pumped according to the conventional process (the vacuum degree is controlled below 10 Pa), and argon is filled (the air pressure needs to be slightly higher than the atmospheric pressure). The above-mentioned other impurity elements include: twelve elements of iron (Fe), copper (Cu), nickel (Ni), molybdenum (Mo), cobalt (Co), manganese (Mn), chromium (Cr), magnesium (Mg), calcium (Ca), aluminum (Al), silicon (Si), and zinc (Zn);

[0092] The surfaces of the two prepared platinum base material ingots containing impurities are respectively milled, and then rolled into thin sheets with a thickness of 0.2 ± 0.05 mm. After rolling, the thin sheets need to be pickled and annealed;

[0093] Take the two annealed thin sheets mentioned above, and respectively use ICP-OES or ICP-MS wet analysis to analyze the content of impurity elements in the platinum base material ingots containing impurities, so as to introduce impurity elements when preparing standard samples later;

[0094] 3) Induction refining of platinum melt

[0095] Place platinum materials meeting the purity requirements (≥99.99 wt%) in a zirconia crucible of an intermediate frequency induction melting furnace, and use intermediate frequency induction heating for melting and refining. The specific operations are as follows:

[0096] Take a new ZrO2 crucible, soak it in a 13% hydrochloric acid solution, boil for 25 min, and control the solution temperature at 90 °C;

[0097] Dry / pour the ZrO2 crucible to remove refractory material impurities on the inner wall;

[0098] Place the weighed platinum in the ZrO2 crucible, and use induction heating to melt the platinum. After the materials are melted, keep the melt temperature 100 °C above the melting point and hold for 20 min; During the holding period, at the same time, evacuate the furnace body, and maintain the vacuum degree at 5 Pa; After the holding ends, stop heating and let the melt cool naturally in the crucible; During the melting and holding period, in addition to being stirred by electromagnetic induction heating itself, the melt is also stirred by a mechanical stirring device to improve the uniformity of the melt composition;

[0099] After the melt is completely solidified, induction heating is started again to melt the metal. Repeat the above steps twice, that is, perform "induction heating and melting → vacuum pumping / heat preservation → natural furnace cooling and solidification" three times to obtain the secondary refined material;

[0100] 4) Atomization powder making

[0101] After the platinum refined material completes the above refining steps, the material solidified for the second time is induction heated and melted again according to the above steps, vacuum is pumped, argon is filled, and secondary feeding and melting are carried out to prepare the platinum powder material containing impurities. The specific steps are as follows:

[0102] Induction heat the above-mentioned secondary refined material again. After melting, keep the melt temperature between 50 °C above the melting point; pump the vacuum of the furnace body, maintain the vacuum degree at 5 Pa, and keep warm for 10 min;

[0103] After the heat preservation time ends, raise the melt temperature to 150 °C above the melting point; add two platinum base metal sheets obtained in step 2) to the melt pool for the second time and keep warm for 5 min. At the same time, inject high-purity argon into the furnace body to make the pressure in the furnace higher than the atmospheric pressure in order to open the atomization channel valve;

[0104] Start the high-pressure atomization powder making equipment, and inject the refined platinum melt containing impurities into the tundish crucible. The melt flows into the atomization channel through the tundish crucible, and the platinum melt is instantly broken into powder by high-pressure atomized water to complete atomization powder making;

[0105] During the above atomization powder making process, the atomization medium: high-purity deionized water; the temperature of the atomization medium is 5 °C; the atomization pressure is 80 MPa; the flow rate of the atomization medium: 75 L / min; the diameter of the tundish crucible leakage hole: 5 mm; the entire atomization cylinder needs to be evacuated first and then filled with inert gas to prevent impurity elements from being oxidized during atomization powder making; the atomization cylinder wall is cooled by sandwich water, and the temperature of the sandwich cold water is 5 °C; the tundish crucible uses electromagnetic induction to stir, heat and keep warm the melt;

[0106] Collect the atomized platinum powder material;

[0107] 5) Drying and screening

[0108] Lay the powder material collected in step 4) flat on a titanium alloy tray and place it in a drying oven. The drying temperature is 120 °C and the drying time is 10 h;

[0109] Screen the dried powder with a 200-mesh sieve, and collect the powder below 200 mesh to flow into the next process;

[0110] 6) Powder sintering

[0111] First, place the platinum-rhodium alloy box on the mullite refractory brick, then load platinum powder with a mesh size below 200 into the platinum-rhodium alloy box, and place the whole in a vacuum sintering atmosphere furnace for sintering treatment; Sintering process: Start heating from room temperature at a rate of 5 °C / min to 800 °C, hold at 800 °C for 300 min, then heat from 800 °C to 1200 °C at a heating rate of 10 °C / min, and hold for 60 min; Finally, cool with the furnace. During the sintering process, evacuate the furnace and then fill it with argon to prevent oxidation and volatilization of impurity elements;

[0112] 7) Compression molding

[0113] Place the sintered platinum sintered pellets containing impurities in the mold cavity, and perform pre-pressing and re-pressing on it; The pre-pressing pressure is 250 MPa. After pre-pressing, anneal the formed body in a vacuum atmosphere furnace, annealing temperature: 1150 °C; Annealing time: 60 min. Before annealing treatment, evacuate the furnace chamber first, and then introduce inert gas before starting heating; Re-press the annealed platinum ingot, and the re-pressing pressure is 450 MPa;

[0114] 8) Hot forging

[0115] Repeatedly hot forge the compression-molded platinum ingot to further increase the density of the platinum ingot and eliminate internal defects. The hot forging temperature is 1300 °C, and repeatedly hot forge; After hot forging, test the density of the platinum ingot, and the actual density value of the platinum ingot is not lower than 99.5% of the theoretical density;

[0116] 9) Repeated cold rolling - heat treatment

[0117] Milling the upper and lower surfaces of the hot-forged platinum ingot to remove surface contamination caused by hot forging, rolling and other processes. The milling depth is 2 mm - 3 mm; Then start cold rolling, and control the rolling deformation amount above 200%; After cold rolling, perform high-temperature vacuum annealing on the sheet, annealing temperature 1300 °C - 1350 °C, annealing time 50 min, evacuate first, and then fill with inert gas; After reaching the annealing time, quickly take out the sheet and place it in ice water for rapid cooling; Repeat this operation until the platinum sheet is rolled to 2 mm;

[0118] 10) Punching and shearing specimens

[0119] According to the requirements of the detection analyzer for the size of the specimen, select a mold of the corresponding size to punch the platinum reference material. Generally, a mold with a diameter of 30.5 mm is used to punch the specimen to obtain a standard material sample with a diameter of 30 mm;

[0120] At the same time, take samples around the base material of the specimen punched and sheared for subsequent ICP detection and analysis to calibrate the platinum content in the reference material;

[0121] 11) Homogenization heat treatment

[0122] Put the blanking standard substance into a platinum-rhodium alloy annealing pan and place it in a vacuum atmosphere furnace for homogenization annealing treatment. According to the difference in the platinum content in the platinum standard substance, select a suitable heat treatment process, with a temperature of 1300°C and a time of 50h. When the standard sample reaches the specified time; when the specified holding time is reached, quickly take out the sample and place it in cold water at 5°C for rapid cooling;

[0123] 12) Grind and polish the standard sample

[0124] Pickle the platinum standard substance after homogenization heat treatment, that is, place the standard substance in a beaker containing 13% dilute hydrochloric acid, heat it to 80°C and keep it warm for 60 minutes to eliminate the residual impurity elements on the surface of the standard substance;

[0125] After pickling the standard substance, use a grinding and polishing machine to grind and polish the upper and lower surfaces of the standard substance until a mirror surface is polished;

[0126] 13) Standard sample value determination

[0127] ICP-OES chemical value determination

[0128] Conduct chemical value determination and analysis on the samples taken around the standard sample base material according to relevant standards: Select different materials for each mass fraction sample piece, cut and mix them evenly, weigh a certain mass of the sample, digest it with aqua regia under high pressure in a microwave, transfer it to a volumetric flask of a certain volume, make up the volume with deionized water, test the impurity standard solution and the standard sample solution on an ICP-OES spectrometer, determine the mass concentration of the impurity elements, and then determine the mass fraction of the impurity elements according to relevant methods;

[0129] Standard substance homogeneity detection

[0130] Randomly select the prepared standard substance sample pieces and conduct homogeneity tests on the standard sample pieces of each mass fraction: According to the requirements of the national standard substance homogeneity test, use an X-ray fluorescence energy spectrometer to conduct non-destructive tests on the platinum standard substance containing impurities;

[0131] Furthermore, use an X-ray fluorescence energy spectrometer to conduct multiple non-destructive tests on different regions of the same standard substance to evaluate the homogeneity of the impurity element distribution of the same sample piece;

[0132] According to the above-mentioned test analysis results, determine the value of the prepared platinum standard substance containing impurities;

[0133] The results are shown in Tables 2 to 6;

[0134] 14) Establish a standard

[0135] Apply the prepared platinum standard substance containing impurities to test on an X-ray fluorescence spectrometer, a spark direct-reading spectrometer or an electron probe instrument to establish a standard curve.

[0136] Table 1 Design Table of Platinum Solid Reference Material Containing Impurity Elements

[0137]

[0138] Table 2 Data Sheet of Platinum Solid Reference Material Containing Impurity Elements - Sample 1

[0139]

[0140]

[0141] Table 3 Data Sheet of Platinum Solid Reference Material Containing Impurity Elements - Sample 2

[0142]

[0143]

[0144] Table 4 Data Sheet of Platinum Solid Reference Material Containing Impurity Elements - Sample 3

[0145]

[0146] Table 5 Data Sheet of Platinum Solid Reference Material Containing Impurity Elements - Sample 4

[0147]

[0148]

[0149] Table 6 Data Sheet of Platinum Solid Reference Material Containing Impurity Elements - Sample 5

[0150]

[0151]

[0152] As can be seen from Table 2 to Table 6, for the platinum solid reference material containing Fe, Cu, Ni, Mo, Co, Mn, Cr, Mg, Ca, Al, Si, Zn, Bi, Pb, As and Sn prepared by the preparation method provided in this application, the designed values of the impurity elements are close to the IPC detection values of the finally prepared platinum solid reference material, that is, the elemental content accuracy of the platinum solid reference material prepared by the preparation method provided in this application is relatively high.

[0153] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0154] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a platinum solid reference material or a platinum alloy solid reference material containing impurity elements, comprising the following steps: S1) Refine the first pure platinum and then add the first impurity metal, and melt to obtain the first platinum base material; the first pure platinum includes the first pure platinum or the first platinum alloy, and the first impurity metal includes one or more of Bi, Pb, As, and Sn; Melt the second impurity metal and the second pure platinum to obtain the second platinum base material; the second pure platinum includes the second pure platinum or the second platinum alloy, and the second impurity metal includes one or more of Fe, Cu, Ni, Mo, Co, Mn, Cr, Mg, Ca, Al, Si, and Zn; S2) Melt pure platinum or a pure platinum alloy and keep it warm. While keeping it warm, evacuate the air, and then cool it. Repeat the above steps at least twice to obtain the refined material; S3) Heat the refined material and keep it warm. While keeping it warm, evacuate the air, and then add the first platinum base material and the second platinum base material for atomization powder making to obtain the powder material; S4) Sinter the powder material and then form it; S5) Hot forge the platinum ingot obtained in step S4), and then perform cold rolling and heat treatment in sequence, and the cold rolling and heat treatment are repeated multiple times; S6) Perform homogenization heat treatment on the initial material obtained in step S5) to obtain the platinum solid reference material or the platinum alloy solid reference material.

2. The preparation method according to claim 1, wherein In step S1), in the step of obtaining the first platinum base material, the melting temperature is 1700 - 1900 °C, and in the step of obtaining the second platinum base material, the melting temperature is 1700 - 1900 °C; And / or, the first platinum alloy includes a platinum-rhodium alloy, a platinum-palladium alloy, or a platinum-rhodium-palladium alloy; And / or, the second platinum alloy includes a platinum-rhodium alloy, a platinum-palladium alloy, or a platinum-rhodium-palladium alloy.

3. The preparation method according to claim 1, characterized in that, In step S2), the melting temperature is 50 - 100 °C above the melting point of pure platinum or the pure platinum alloy, the heat preservation time is 10 - 20 min, and the vacuum degree of the evacuation is below 10 Pa.

4. The preparation method according to claim 1, characterized in that, In step S2), stirring is performed during the heat preservation, and the stirring includes electromagnetic induction heating stirring and mechanical stirring.

5. The preparation method according to claim 1, characterized in that, In step S3), the heating temperature is 50 - 100 °C above the melting point of the refined material, the vacuum degree of the evacuation is below 10 Pa, and the heat preservation time is 10 - 20 min.

6. The preparation method according to claim 5, wherein In step S3), before adding the first platinum base material and the second platinum base material, it further includes: Raise the temperature of the melt after heat preservation to 150 - 200 °C above the melting point; After adding the first platinum base material and the second platinum base material, heat preservation is also included, and the heat preservation time is 5 - 10 min.

7. The preparation method according to claim 6, characterized in that, The atomization powder making specifically is: Inject high-purity argon gas into the furnace body; Start the high-pressure atomization powder making equipment, inject the melt after heat preservation into the tundish crucible, and the melt flows into the atomization channel through the tundish crucible for atomization powder making; And / or, the medium for atomization powder making is high-purity deionized water, the temperature of the medium is 0 - 10°C, the pressure for atomization powder making is 50 - 100 MPa, the medium flow rate for atomization powder making is 50 - 150 L / min, the diameter of the tundish crucible leakage hole for atomization powder making is 3 - 10 mm, the atomization cylinder wall for atomization powder making adopts sandwich water cooling, and the temperature of the sandwich water is 0 - 10°C.

8. The preparation method according to claim 7, characterized in that, In step S4), the specific sintering process is as follows: The powder material is heated from room temperature to 800 - 900°C at a rate of 5 - 10°C / min, held for 300 - 400 min, then heated to 1200 - 1300°C at a rate of 10 - 15°C / min, held for 60 - 80 min, and finally cooled with the furnace. And / or, the sintering is carried out in vacuum sintering. And / or, the forming includes pre-pressing and re-pressing carried out in sequence. The pressure of the pre-pressing is 200 - 300 MPa, and the pressure of the re-pressing is 400 - 500 MPa; an annealing treatment is also included between the pre-pressing and the re-pressing. The temperature of the annealing treatment is 1000 - 1200°C, and the time is 50 - 100 min.

9. The preparation method according to claim 8, wherein, In step S5), the temperature of the hot forging is 1000 - 1500°C, the number of hot forging times is at least 1 time, and the density of the platinum ingot after hot forging is not less than 99.5% of the theoretical density. And / or, the deformation amount of the cold rolling is greater than 200%. And / or, the temperature of the heat treatment is 1300 - 1400°C, the time is 30 - 60 min, and the heat treatment is carried out in an inert atmosphere. And / or, the thickness of the platinum ingot after repeating multiple times is 1.5 - 3.5 mm.

10. The preparation method according to claim 9, characterized in that, In step S6), the temperature of the homogenization heat treatment is 1300 - 1500°C, and the time is 50 - 60 h.

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