Method for determining quality and purity of gold and silver in gold and silver commemorative coin

Abstract

The invention provides a method for determining the quality and purity of gold and silver in a gold and silver commemorative coin, and belongs to the field of analysis and detection. Wherein gold and silver in the gold and silver commemorative coin are separated to obtain a gold sample and a silver sample, the gold sample and the silver sample are weighed respectively, and finally, an equivalent concentration deduction method and an internal standard method are combined to measure the purity of the gold sample and / or the silver sample. The method for measuring the purity of the gold sample comprises the following steps: respectively preparing a solution A1, a solution A2 and a standard solution A3n; determining the impurity element concentrations C1i and C2i in the solution A1 and the solution A2 by using an ICP-AES spectrometer; and omega Au is calculated. The method for measuring the purity of the silver sample comprises the following steps: respectively preparing a solution B1, a solution B2 and a standard solution B3n; determining the impurity element concentrations D1j and D2j in the solution B1 and the solution B2 by using an ICP-AES spectrometer; and omega Ag is calculated. The method is beneficial for improving the quality and purity measurement precision of gold and silver in the gold and silver commemorative coin.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of analytical detection technology, and particularly relates to a method for measuring the quality and purity of gold and silver in gold and silver commemorative coins. BACKGROUND

[0002] Gold and silver commemorative coins not only have the investment properties of precious metals, but also carry rich cultural connotations and artistic value, and are special commodities with both practicality and collectibility. Each gold and silver commemorative coin needs to be detected for quality and purity before being sold to issue relevant certificates. Gold and silver commemorative coins not only contain precious metals gold and silver, but also contain a plating layer connecting gold and silver, and a paint layer attached to the surface of the commemorative coin for decoration. The quality of existing precious metal jewelry is mostly measured according to the method provided in QB / T 1690-2004 "Provisions for Measurement of Tolerance of Quality of Precious Metal Jewelry", which is only applicable to the detection of pure matrix of precious metals, and is difficult to measure the quality of gold and silver in gold and silver commemorative coins with mixed matrix. The purity of existing precious metal jewelry is mostly non-destructively detected according to GB / T 18043-2013 "Determination of Precious Metal Content in Jewelry - X-ray Fluorescence Spectrometry", and the X-ray fluorescence spectrometry mainly uses X-rays to penetrate the metal surface for testing. This method has fast analysis speed and does not damage the sample during the measurement process, but the penetration of X-rays is generally not more than 10 μm, which is only applicable to the detection of pure matrix with good uniformity and no sandwiching or wrapping phenomenon, and is not suitable for the detection of mixed matrix such as gold and silver commemorative coins. Therefore, the quality and purity of gold and silver in gold and silver commemorative coins are mostly detected by separating gold and silver first and then detecting them respectively.

[0003] In the prior art, aluminum is mostly used to connect gold and silver in gold and silver commemorative coins, that is, aluminum plating layer is used as the sandwich layer between gold and silver. On the one hand, the aluminum plating layer has high matching degree with the thermal expansion coefficient of the gold and silver matrix, which can reduce the peeling phenomenon of the plating layer caused by temperature change; on the other hand, the aluminum plating layer has obvious advantages in cost, process maturity and environmental friendliness, and is easier to process into a pattern with strong three-dimensionality, and thus is widely used. However, it is often difficult to fully remove the aluminum plating layer and the paint layer attached to the surface of gold and silver during the detection process, which causes interference to the test results. In addition, the measurement precision and accuracy of X-ray fluorescence spectrometry are poor, and the RSD (relative standard deviation) is generally between 0.1%-0.5%. Even if the aluminum plating layer and the paint layer are fully peeled off, the test precision is still not high.

[0004] Therefore, it is necessary to design a method for measuring the quality and purity of gold and silver in gold and silver commemorative coins to solve the above problems. SUMMARY

[0005] In view of the technical problems existing in the background art, the application provides a method for determining the quality and purity of gold and silver in gold and silver commemorative coins, aiming to solve the technical problem of inaccurate test results of the quality and purity of gold and silver in gold and silver commemorative coins caused by the difficulty in removing the aluminum plating layer and the coating layer and the poor measurement precision and accuracy of X fluorescence spectrometry.

[0006] The application embodiment provides a method for determining the quality and purity of gold and silver in gold and silver commemorative coins, which separates gold and silver in gold and silver commemorative coins to obtain a gold sample and a silver sample, then weighs the gold sample to obtain a mass m1g, weighs the silver sample to obtain a mass m2g, and finally combines equivalent concentration deduction method and internal standard method to determine the purity of the gold sample and / or the silver sample by using an ICP-AES spectrometer; wherein, The steps for determining the purity of the gold sample by combining the equivalent concentration deduction method and the internal standard method include the following steps: S1, respectively preparing solution A1, solution A2 and standard solution A 3n ; the solution A1 contains yttrium internal standard and m3g of the gold sample, the solution A2 contains yttrium internal standard and m3g of high-purity gold sample, and the standard solution A3 contains yttrium internal standard and multiple impurity elements; S2, determining the impurity element concentration in the solution A1 by using an ICP-AES spectrometer, denoted as C 1i , and determining the impurity element concentration in the solution A2, denoted as C 2i ; S3, calculating the purity ω Au of the gold sample; The steps for determining the purity of the silver sample by combining the equivalent concentration deduction method and the internal standard method include the following steps: S4, respectively preparing solution B1, solution B2 and standard solution B 3n ; the solution B1 contains yttrium internal standard and m4g of the silver sample, the solution B2 contains yttrium internal standard and m4g of high-purity silver sample, and the standard solution B3 contains yttrium internal standard and multiple impurity elements; S5, determining the impurity element concentration in the solution B1 by using an ICP-AES spectrometer, denoted as D 1j , and determining the impurity element concentration in the solution B2, denoted as D 2j ; S6, calculating the purity ω Ag of the silver sample.

[0007] Wherein, steps S1 to S6 are only set for the convenience of description, and do not limit the determination order of the gold sample and the silver sample (such as measuring gold first or measuring silver first).

[0008] In the technical scheme of the embodiment of the application, the equivalent concentration deduction method and the internal standard method are combined, the ICP-AES is used to measure the impurity element concentration in gold and silver, and then the purity of gold and silver is obtained through the difference deduction method. The test precision is effectively improved by the synergistic effect of the equivalent concentration deduction method and the internal standard method. This is because, when only the internal standard method is used, on the one hand, a large amount of matrix elements (gold / silver) will inhibit the ionization of impurity elements (such as iridium, arsenic) in the sample, so that the element exists in the atomic state, thereby causing the atomic emission spectrum signal to be enhanced, that is, the positive interference of the matrix effect is generated, however, the ionization of yttrium is not inhibited by the matrix effect, so that the arsenic and iridium elements in gold cannot be corrected by the internal standard element, resulting in that the measurement results of the arsenic and iridium elements are too high, and finally the purity of gold and silver is seriously low. On the other hand, the matrix of the sample solution and the blank solution is different, the atomization efficiency is inconsistent, and the test results will also have a certain deviation. The equivalent concentration deduction method and the internal standard method are used in cooperation, the positive interference generated by the matrix effect can be eliminated, the problem that the arsenic and iridium elements cannot be corrected by the yttrium internal standard in the internal standard method can be solved, the measurement accuracy of the impurity element content is improved, and the precision of the gold and silver purity test is improved.

[0009] In some embodiments, the steps of preparing the solution A1 and the solution A2 include dissolving the sample under heating conditions with aqua regia, then adding a yttrium internal standard solution, and finally diluting with water; the steps of preparing the solution B1 and the solution B2 include dissolving the sample under heating conditions with nitric acid, then adding a yttrium internal standard solution, and finally diluting with water; the steps of preparing the standard solution A 3n include mixing the yttrium internal standard solution, the mixed standard solution A4 containing a plurality of impurity elements, and aqua regia, and then diluting with water; the steps of preparing the standard solution B 3n include mixing the yttrium internal standard solution, the mixed standard solution B4 containing a plurality of impurity elements, and nitric acid, and then diluting with water.

[0010] In this embodiment, the yttrium internal standard is added to the solution A1, the solution A2, the standard solution A 3n , the solution B1, the solution B2, and the standard solution B 3n for correcting the signal drift of the elements to be measured, and because the ionization of the arsenic and iridium elements is inhibited, the yttrium cannot correct the signal drift of the arsenic and iridium. The purpose of the solution A2 and the solution B2 in this embodiment is to eliminate the positive interference caused by the matrix effect, so as to accurately test the content of the arsenic, iridium and other elements.

[0011] In some embodiments, the impurity element concentrations in the standard solution A 31 ,..., A 3n are in an arithmetic progression, and the impurity element concentrations in the standard solution B 31 ,..., B 3n are in an arithmetic progression.

[0012] In this embodiment, the impurity element concentration ranges in the standard solution A 31 ,..., A 3n and the standard solution B 31 ,..., B 3n are in an arithmetic progression, so that a standard curve can be drawn to determine the impurity element concentrations in the solution A1, the solution A2, the solution B1 and the solution B2.

[0013] In some embodiments, n is a natural integer from 1 to 5, the impurity element concentrations in the standard solution A 31 , A 32 , A 33 , A 34 , A 35 are respectively 0 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, 10.0 μg / mL, and the impurity element concentrations in the standard solution B 31 , B 32 , B 33 , B 34 , B 35 are respectively 0 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, 10.0 μg / mL.

[0014] In this embodiment, the standard curve has 5 points.

[0015] In some embodiments, the yttrium concentrations in the solution A1, the solution A2, the standard solution A 3n , the solution B1, the solution B2 and the standard solution B 3n are 1.5-2.5 μg / mL; the impurity elements contained in the mixed standard solution A4 include Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, Na; the impurity elements contained in the mixed standard solution B4 include Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, Na; the purities of the high-purity gold sample and the high-purity silver sample are greater than or equal to 99.999%.

[0016] In this embodiment, the accuracy of the calculated gold and silver purities reaches 0.001% by subtracting the contents of the common impurity elements in 23 gold matrices and the common impurity elements in 20 silver matrices by using the difference method.

[0017] In some embodiments, the solution A1, the solution A2 and the standard solution A have equal volumes, all recorded as V1, the gold sample purity ω 3n The calculation formula of the gold sample purity ω Au is as follows: wherein, ∑(C 1i -C 2i ) represents the sum of the concentrations of all impurity elements after deducting the blank; i is a natural integer from 1 to 23, respectively corresponding to the impurity elements Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, Na.

[0018] In some embodiments, the solution B1, the solution B2 and the standard solution B have equal volumes, all recorded as V2, the silver sample purity ω 3n The calculation formula of the silver sample purity ω Ag is as follows: wherein, ∑(D 1j -D 2j ) represents the sum of the concentrations of all impurity elements after deducting the blank; j is a natural integer from 1 to 20, respectively corresponding to the impurity elements Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, Na.

[0019] In some embodiments, the gold and silver in the gold and silver commemorative coin are separated by the following steps: SS1, placing the gold and silver commemorative coin in an inert gas atmosphere, heating to a first temperature for a first time, to obtain a gold sample P1 with aluminum attached to the surface and a silver sample P2 with aluminum attached to the surface; SS2, placing the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface obtained in step SS1 in dilute hydrochloric acid respectively, heating to a second temperature for a second time, removing the solution, and repeating the treatment with dilute hydrochloric acid for 2-4 times to obtain a gold sample P3 and a silver sample P4; SS3, washing the gold sample P3 and the silver sample P4 obtained in step SS2 with an ammonium nitrate solution under heating conditions, then washing with water for 3-5 times, and drying to obtain the gold sample and the silver sample.

[0020] In some embodiments, the first temperature is 660-700℃, the first time is 15-30min; the second temperature is 200-250℃, the second time is the time required for dissolving the aluminum on the surface of the gold sample P1 and the aluminum on the surface of the silver sample P2; the time for washing the gold sample P3 and the silver sample P4 with the ammonium nitrate solution is 5-10min.

[0021] In this embodiment, the gold and silver commemorative coins are placed in an inert gas atmosphere for high-temperature treatment, which can effectively remove the paint layer on the surface of the commemorative coins, and at the same time, the aluminum plating layer is melted, so that the gold and silver are separated, which is beneficial for subsequent processing of the gold and silver separately. The inert gas atmosphere can avoid the problem of inaccurate (higher) quality test caused by oxidation of silver at high temperature. In addition, the residual aluminum on the surface of the sample can be dissolved and washed away by dilute hydrochloric acid without damaging the appearance and shape of the sample. Washing with the ammonium nitrate solution can remove the chloride ions attached to the surface of the sample, avoiding the formation of silver chloride precipitate after the silver is dissolved by nitric acid and wrapping impurity elements, which affects the test precision.

[0022] In some embodiments, the concentration of the dilute hydrochloric acid is 25-33%; the concentration of the ammonium nitrate solution is 20-25g / L.

[0023] The beneficial effects of the present application are as follows: The present application provides a method for determining the quality and purity of gold and silver in gold and silver commemorative coins, which combines equivalent concentration deduction method and internal standard method, uses ICP-AES to determine the impurity element concentration in gold and silver, and then obtains the purity of gold and silver through difference method. The synergistic effect of the equivalent concentration deduction method and the internal standard method effectively improves the test precision. This is because, when only the internal standard method is used, on the one hand, a large amount of matrix elements (gold / silver) will inhibit the ionization of impurity elements (such as iridium, arsenic) in the sample, so that the element exists in the form of atom, thereby causing the atomic spectrum signal of the element to be enhanced, i.e. the positive interference of matrix effect, however, the matrix effect does not inhibit the ionization of yttrium, so that the arsenic and iridium elements in gold cannot be corrected by the internal standard element, resulting in that the determination results of arsenic and iridium elements are higher, and finally the calculated purity of gold and silver is seriously low; on the other hand, the matrix of the sample solution and the blank solution is different, the atomization efficiency is inconsistent, and the test results will also have certain deviation. The synergistic effect of the equivalent concentration deduction method and the internal standard method can eliminate the positive interference of the matrix effect, solve the problem that the arsenic and iridium elements cannot be corrected by the yttrium internal standard in the internal standard method, improve the measurement accuracy of the impurity element content, and thus improve the precision of the gold and silver purity test.

[0024] The gold and silver commemorative coins are first placed in an inert gas atmosphere for high-temperature treatment to remove the paint layer on the surface of the commemorative coins, and the aluminum plating layer is melted to separate the gold and silver, which is beneficial to subsequent separate processing of the gold and silver. The inert gas atmosphere can avoid the problem of inaccurate (high) subsequent quality testing caused by oxidation of silver at high temperature. Then, the sample surface is treated with dilute hydrochloric acid at high temperature for multiple times to dissolve and wash away the residual aluminum on the sample surface without damaging the appearance shape of the sample. Subsequently, washing with an ammonium nitrate solution can remove the chloride ions attached to the surface of the sample, avoiding the formation of silver chloride precipitate after the silver is dissolved by nitric acid and wrapping impurity elements, which affects the testing precision. The foregoing scheme solves the technical problems of removing the paint layer and the aluminum plating layer, avoids the introduction of new impurities, and effectively improves the testing accuracy.

[0025] The foregoing merely describes the technical scheme of the present application, and in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. DETAILED DESCRIPTION

[0026] The embodiments of the technical scheme of the present application will be described in detail below. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusion.

[0028] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0029] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can 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 all refer to the same embodiment, nor is it necessarily mutually exclusive or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments of the present application, the term "and / or" is merely to describe an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing simultaneously, and B existing alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0031] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of kinds" refers to two or more kinds (including two pieces). For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0032] In order to solve the technical problems that the aluminum plating layer and the paint layer are difficult to remove, the measurement precision and accuracy of X fluorescence spectrum method are poor, and the mass and purity of gold and silver in gold and silver commemorative coins are not accurate, the present application provides a method for measuring the mass and purity of gold and silver in gold and silver commemorative coins, wherein the equivalent concentration deduction method and the internal standard method are combined, the ICP-AES is used to measure the impurity element concentration in gold and silver, and then the purity of gold and silver is obtained by difference. The equivalent concentration deduction method and the internal standard method are used in cooperation to effectively improve the test precision. In the process of separating gold and silver in gold and silver commemorative coins, the gold and silver commemorative coins are first placed in an inert gas atmosphere for high temperature treatment, and then treated with dilute hydrochloric acid at high temperature for multiple times, and then washed with ammonium nitrate solution and water, which solves the technical problem of removing the paint layer and the aluminum plating layer, avoids introducing new impurities, and effectively improves the test accuracy.

[0033] The embodiments of the present application provide a method for measuring the mass and purity of gold and silver in gold and silver commemorative coins, separating gold and silver in gold and silver commemorative coins to obtain gold samples and silver samples, weighing the gold sample to obtain the mass m1g, weighing the silver sample to obtain the mass m2g, and finally combining the equivalent concentration deduction method and the internal standard method to measure the purity of the gold sample and / or the silver sample by using an ICP-AES spectrometer; wherein, The combination of the equivalent concentration deduction method and the internal standard method for measuring the purity of the gold sample includes the following steps: S1, respectively preparing solution A1, solution A2 and standard solution A 3n ; solution A1 contains yttrium internal standard and m3g gold sample, solution A2 contains yttrium internal standard and m3g high-purity gold sample, and standard solution A3 contains yttrium internal standard and a plurality of impurity elements; S2, using an ICP-AES spectrometer to measure the impurity element concentration in solution A1, denoted as C 1i , and measuring the impurity element concentration in solution A2, denoted as C 2i ; S3, calculating the purity ω of the gold sampleAu ; The purity of the silver sample is determined by combining the equivalent concentration deduction method and the internal standard method, including the following steps: S4, respectively preparing solution B1, solution B2 and standard solution B 3n ; solution B1 contains yttrium internal standard and m4g silver sample, solution B2 contains yttrium internal standard and m4g high-purity silver sample, and standard solution B3 contains yttrium internal standard and multiple impurity elements; S5, determining the impurity element concentration in solution B1 by ICP-AES spectrometer, denoted as D 1j , determining the impurity element concentration in solution B2, denoted as D 2j ; S6, calculating the purity ω Ag of the silver sample.

[0034] In the technical scheme of the embodiments of the present application, the equivalent concentration deduction method and the internal standard method are combined, the impurity element concentration in gold and silver is determined by ICP-AES, and then the purity of gold and silver is obtained by difference method. The test precision is effectively improved by the synergistic effect of the equivalent concentration deduction method and the internal standard method. This is because, when only the internal standard method is used, on the one hand, a large amount of matrix elements (gold / silver) will inhibit the ionization of impurity elements (such as iridium, arsenic) in the sample, so that the element exists in the form of atom, thereby causing the atomic emission spectrum signal to be enhanced, that is, the positive interference of matrix effect is produced, however, the matrix effect does not inhibit the ionization of yttrium, so that the arsenic and iridium elements in gold cannot be corrected by the internal standard element, resulting in that the determination results of arsenic, iridium and other elements are high, and finally the purity of gold and silver is seriously low. On the other hand, the matrix of sample solution and blank solution is different, the atomization efficiency is inconsistent, and the test result also has a certain deviation. The positive interference of matrix effect can be eliminated by the synergistic effect of the equivalent concentration deduction method and the internal standard method, the problem that the arsenic and iridium elements cannot be corrected by the yttrium internal standard in the internal standard method is solved, the measurement accuracy of impurity element content is improved, and the precision of gold and silver purity test is improved.

[0035] Further, the steps of preparing solution A1 and solution A2 include dissolving the sample under heating condition with aqua regia, then adding yttrium internal standard solution, and finally diluting with water; the steps of preparing solution B1 and solution B2 include dissolving the sample under heating condition with nitric acid, then adding yttrium internal standard solution, and finally diluting with water; the steps of preparing standard solution A 3n include mixing yttrium internal standard solution, mixed standard solution A4 containing multiple impurity elements and aqua regia, and then diluting with water; the steps of preparing standard solution B 3n include mixing yttrium internal standard solution, mixed standard solution B4 containing multiple impurity elements and nitric acid, and then diluting with water.

[0036] The preparation method of the yttrium internal standard solution is as follows: yttrium oxide (Y2O3) is added to nitric acid, heated to a clear and transparent state, cooled to room temperature, and diluted with water, and mixed evenly. The concentration of the yttrium internal standard solution used in the application is 50 ug / mL, the concentration of the mixed standard solution A4 is 50 ug / mL, and the concentration of the mixed standard solution B4 is 50 ug / mL.

[0037] In the technical scheme of the embodiment of the application, yttrium internal standards are added to solution A1, solution A2, standard solution A 3n , solution B1, solution B2 and standard solution B 3n , so as to correct the signal drift of the elements to be measured. However, since the ionization of arsenic and iridium elements is inhibited, yttrium cannot correct the signal drift of arsenic and iridium. The purpose of setting solution A2 and solution B2 in this embodiment is to subtract the positive interference caused by the matrix effect, so as to accurately test the content of elements such as arsenic and iridium.

[0038] Further, the impurity element concentrations in standard solution A 31 ,..., A 3n are in an arithmetic progression, and the impurity element concentrations in standard solution B 31 ,..., B 3n are in an arithmetic progression.

[0039] In the technical scheme of the embodiment of the application, the impurity element concentration ranges in standard solution A 31 ,..., A 3n and standard solution B 31 ,..., B 3n are in an arithmetic progression, so that a standard curve can be drawn, and the impurity element concentrations in solution A1, solution A2, solution B1 and solution B2 can be determined through the standard curve.

[0040] Further, n is a natural integer from 1 to 5, the impurity element concentrations in standard solution A 31 , A 32 , A 33 , A 34 , A 35 are 0 ug / mL, 1.0 ug / mL, 3.0 ug / mL, 5.0 ug / mL and 10.0 ug / mL respectively, and the impurity element concentrations in standard solution B 31 , B 32 , B 33 , B 34 , B 35 are 0 ug / mL, 1.0 ug / mL, 3.0 ug / mL, 5.0 ug / mL and 10.0 ug / mL respectively.

[0041] In the technical scheme of the embodiment of the present application, the standard curve is 5 points.

[0042] Further, the yttrium concentration in the solution A1, the solution A2, the standard solution A 3n , the solution B1, the solution B2 and the standard solution B 3n is 1.5-2.5 μg / mL; the impurity elements contained in the mixed standard solution A4 include Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, Na; the impurity elements contained in the mixed standard solution B4 include Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, Na; the purity of the high-purity gold sample and the high-purity silver sample is greater than or equal to 99.999%.

[0043] In the technical scheme of the embodiment of the present application, the gold and silver purity calculated by subtracting the contents of the common impurity elements in the 23 gold matrices and the common impurity elements in the 20 silver matrices by using the difference method reaches the accuracy of 0.001%.

[0044] Further, the volumes of the solution A1, the solution A2 and the standard solution A 3n are equal, and are recorded as V1, and the calculation formula of the gold sample purity ω Au is as follows: , wherein, ∑(C 1i -C 2i ) represents the sum of the concentrations of all impurity elements after deducting the blank, i is a natural integer from 1 to 23, and respectively corresponds to the impurity elements Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn and Na.

[0045] Further, the volumes of the solution B1, the solution B2 and the standard solution B 3n are equal, and are recorded as V2, and the calculation formula of the silver sample purity ω Ag is as follows: , wherein, ∑(D 1j -D 2j ) represents the sum of the concentrations of all impurity elements after deducting the blank, j is a natural integer from 1 to 20, and respectively corresponds to the impurity elements Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn and Na.

[0046] Further, the gold and silver commemorative coin has an aluminum plating layer; separating the gold and silver in the gold and silver commemorative coin comprises the following steps: SS1, placing the gold and silver commemorative coin in an inert gas atmosphere, heating to a first temperature for a first time, to obtain a gold sample P1 with aluminum attached to the surface and a silver sample P2 with aluminum attached to the surface; SS2, placing the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface obtained in step SS1 in dilute hydrochloric acid respectively, heating to a second temperature for a second time, removing the solution, and repeating the treatment with dilute hydrochloric acid for 2-4 times, to obtain a gold sample P3 and a silver sample P4; SS3, washing the gold sample P3 and the silver sample P4 obtained in step SS2 with an ammonium nitrate solution under heating, and then washing with water for 3-5 times, and drying, to obtain a gold sample and a silver sample.

[0047] Further, the first temperature is 660-700℃, and the first time is 15-30 min; the second temperature is 200-250℃, and the second time is the time required for dissolving the aluminum on the surface of the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface; and the time for washing the gold sample P3 and the silver sample P4 with the ammonium nitrate solution is 5-10 min.

[0048] In the technical scheme of the embodiments of the present application, placing the gold and silver commemorative coin in an inert gas atmosphere for high-temperature treatment can effectively remove the paint layer on the surface of the commemorative coin, and at the same time, the aluminum plating layer is melted, so that the gold and silver are separated, which is conducive to subsequent separate treatment of the gold and silver. The inert gas atmosphere can avoid the problem of inaccurate (higher) quality test caused by oxidation of silver at high temperature. In addition, treatment with dilute hydrochloric acid can dissolve and wash away the residual aluminum on the surface of the sample without damaging the appearance and shape of the sample. Washing with the ammonium nitrate solution can remove the chloride ions attached to the surface of the sample, avoiding the formation of silver chloride precipitate after the silver is dissolved by nitric acid and the wrapping of impurity elements, which affects the test precision.

[0049] Further, the concentration of the dilute hydrochloric acid is 25-33%, and the concentration of the ammonium nitrate solution is 20-25 g / L.

[0050] Further, the inert gas atmosphere is selected from one of argon, helium, and nitrogen.

[0051] 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 cannot be understood as a limitation of the present application. If the specific technology or condition is not specified in the examples, it is performed according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0052] Example 1 The embodiment 1 provides a method for determining the mass and purity of gold and silver in a gold-silver commemorative coin. The gold-silver commemorative coin used in the test is marked as CC-1, and the CC-1 contains an aluminum plating layer. The determination method is as follows: (1) Separate the gold and silver in the gold-silver commemorative coin, the specific steps including: SS1, place the gold-silver commemorative coin in an argon atmosphere, heat to 660 ℃ for 15 min, to obtain a gold sample P1 with aluminum attached to the surface and a silver sample P2 with aluminum attached to the surface; SS2, place the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface obtained in step SS1 in a 25% concentrated dilute hydrochloric acid, heat to 200 ℃ until the aluminum on the surface of the sample is completely dissolved, remove the solution, and repeat the treatment with dilute hydrochloric acid for 2 times, to obtain a gold sample P3 and a silver sample P4; SS3, wash the gold sample P3 and the silver sample P4 obtained in step SS2 with a 20 g / L ammonium nitrate solution under heating conditions, then wash with water for 3 times, heat in a 100 ℃ electric oven for 60 min, to obtain a gold sample and a silver sample.

[0053] (2) Weigh the gold sample to obtain a mass of 0.5003 g, and weigh the silver sample to obtain a mass of 30.0045 g.

[0054] (3) Combine the equivalent concentration deduction method with the internal standard method to determine the purity of the gold sample and / or the silver sample by using an ICP-AES spectrometer, wherein, The combination of the equivalent concentration deduction method and the internal standard method for determining the purity of the gold sample includes the following steps: S1, prepare solution A1, solution A2 and standard solution A 3n n is a natural integer from 1 to 5.

[0055] Solution A1 contains 2 ug / mL of yttrium internal standard and 0.2500 g of gold sample. The preparation method of solution A1 is as follows: weigh 0.2500 g of gold sample and place it in a polytetrafluoroethylene beaker, add 2.5 mL of aqua regia, heat until the gold is completely dissolved, transfer the solution to a 25 mL volumetric flask with water, add 1.00 mL of yttrium internal standard standard solution with a concentration of 50 ug / mL, dilute to volume with water, mix well, and the volume of solution A1 is recorded as V1, V1=25 mL.

[0056] The preparation method of the yttrium internal standard solution in the embodiment of the application is as follows: weigh 0.6349 g of yttrium oxide (Y2O3) and place it in a beaker, add 20 mL of 50% concentrated nitric acid, heat until the solution is clear and transparent, then cool to room temperature, dilute to 100 mL in a volumetric flask with water, and mix well. The yttrium internal standard solution used in the subsequent steps is prepared by this method and will not be repeated here.

[0057] Solution A2 contains 2 ug / mL yttrium internal standard and 0.2500g high purity gold sample. Solution A2 is prepared by weighing 0.2500g high purity gold sample into a Teflon beaker, adding 2.5 mL aqua regia, heating to complete dissolution of gold, transferring the solution into a 25 mL volumetric flask with water, adding 1.00 mL yttrium internal standard standard solution with a concentration of 50 ug / mL, diluting to volume with water, mixing well, and the volume of solution A2 is also recorded as V1, V1=25mL.

[0058] Standard solution A 3n contains 2 ug / mL yttrium internal standard and various impurity elements. Standard solution A 3n includes A 31 , A 32 , A 33 , A 34 , A 35 is prepared by taking 5 25 mL volumetric flasks, first adding 1.00 mL yttrium internal standard standard solution with a concentration of 50 ug / mL to each, then adding 0 mL, 0.50 mL, 1.50 mL, 2.50 mL, 5.00 mL mixed standard solution to each in turn, then adding 2.5 mL aqua regia to each, diluting to volume with water, and mixing well. The mixed standard solution contains various impurity elements with a concentration of 50 ug / mL, and the impurity elements include Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, Na. Therefore, the impurity element concentrations in standard solution A 31 , A 32 , A 33 , A 34 , A 35 are 0 ug / mL, 1.0 ug / mL, 3.0 ug / mL, 5.0 ug / mL, 10.0 ug / mL respectively. The volume of standard solution A 3n is also recorded as V1, V1=25mL.

[0059] S2, the impurity element concentration in solution A1 is measured by ICP-AES spectrometer, recorded as C 1i , the impurity element concentration in solution A2 is measured, recorded as C 2i , i is a natural integer from 1 to 23, corresponding to impurity elements Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, Na respectively. The impurity element concentrations C 1i and C 2i measured in Example 1 are shown in Table 1.

[0060] Table 1 Impurity element content in gold sample S3, calculate the purity ω of the gold sample Au , the purity ω of the gold sample Au The calculation formula is: wherein, ω Au The unit of ω is %, the unit of V1 is mL, and the unit of m3 is g; ∑(C 1i -C 2i ) represents the sum of the concentrations of all impurity elements after deducting the blank, and the unit is μg / mL.

[0061] It is calculated that ω Au = 99.902%.

[0062] The purity of the silver sample is determined by combining the equivalent concentration deduction method with the internal standard method, including the following steps: S4, respectively prepare solution B1, solution B2 and standard solution B 3n , and n is a natural integer from 1 to 5.

[0063] Solution B1 contains 2 ug / mL of yttrium internal standard and 0.5000g of silver sample. The preparation method of solution B1 is to weigh 0.5000g of silver sample and place it in a polytetrafluoroethylene beaker, add 5 mL of nitric acid, heat until the silver is completely dissolved, transfer the solution to a 50 mL volumetric flask with water, add 2.00 mL of yttrium internal standard standard solution with a concentration of 50 ug / mL, dilute with water, mix well, and the volume of solution B1 is recorded as V2, V2=50mL.

[0064] Solution B2 contains 2 ug / mL of yttrium internal standard and 0.5000g of high-purity silver sample. The preparation method of solution B2 is to weigh 0.5000g of high-purity silver sample and place it in a polytetrafluoroethylene beaker, add 5 mL of nitric acid, heat until the silver is completely dissolved, transfer the solution to a 50 mL volumetric flask with water, add 2.00 mL of yttrium internal standard standard solution with a concentration of 50 ug / mL, dilute with water, mix well, and the volume of solution B2 is also recorded as V2, V2=50mL.

[0065] Standard solution B3 contains 2 ug / mL of yttrium internal standard and multiple impurity elements. Standard solution B 3n includes B 31 , B 32 , B 33 , B 34 , B 35, the preparation method is that 5 50 mL volumetric flasks are taken, first 2.00 mL of yttrium internal standard solution with a concentration of 50 ug / mL is added respectively, then 0 mL, 0.50 mL, 1.50 mL, 2.50 mL, 5.00 mL of mixed standard solution are added respectively, then 5 mL of nitric acid is added, and water is added to constant volume, and mixed. The mixed standard solution contains a plurality of impurity elements with a concentration of 100 ug / mL, and the impurity elements include Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, Na. Therefore, the impurity element concentration in standard solution B 31 , B 32 , B 33 , B 34 , B 35 is 0 ug / mL, 1.0 ug / mL, 3.0 ug / mL, 5.0 ug / mL, 10.0 ug / mL respectively. The volume of standard solution B 3n is also recorded as V2, V2=50mL.

[0066] S5, the impurity element concentration in solution B1 is measured by ICP-AES spectrometer, recorded as D 1j , and the impurity element concentration in solution B2 is measured, recorded as D 2j . j is a natural integer from 1 to 20, corresponding to impurity elements Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, Na respectively. The impurity element concentration D 1j and D 2j measured in Example 1 are shown in Table 1.

[0067] Table 2 Impurity element content in silver sample S6, calculate the purity ω Ag of the silver sample, and the calculation formula of the purity ω Ag of the silver sample is: , wherein, The unit of ω Ag is %, the unit of V2 is mL, and the unit of m4 is g; ∑(D 1j -D 2j ) represents the sum of all impurity element concentrations after deducting the blank, and the unit is ug / mL.

[0068] It is calculated that ω Ag =99.901%.

[0069] That is, the mass m1 of gold determined in Example 1 is 0.5003 g, and the purity is 99.902%; the mass m2 of silver is 30.0045 g, and the purity is 99.901%.

[0070] Example 2 Example 2 is different from Example 1 in that the gold and silver commemorative coin used for testing is CC-2, which also contains an aluminum plating layer, and the other aspects are the same as those of Example 1, which will not be repeated here.

[0071] The mass of gold determined in Example 2 is 0.2504 g, and the purity is 99.954%; the mass of silver is 20.0221 g, and the purity is 99.948%.

[0072] Experimental Example 1 Experimental Example 1 is different from Example 1 in that the national standard sample GSB 04-3312-2016 (No. 1) is used for testing the purity of gold, that is, the equivalent concentration deduction method is directly combined with the internal standard method, and the purity of the gold sample is determined by using an ICP-AES spectrometer, and the other aspects are the same as those of Example 1, which will not be repeated here. The gold purity determination results of Experimental Example 1 and the reference values of the national standard sample are compared and shown in Table 3.

[0073] Table 3 Comparison of gold purity determination results and reference values of Experimental Example 1 As can be seen from the comparison, the deviation between the impurity content of the gold sample determined in Experimental Example 1 and the reference value is not more than 0.0002%, and the final calculated gold purity differs from the reference value by only 0.001%.

[0074] Experimental Example 2 Experimental Example 2 is different from Example 1 in that the national standard sample GSB 04-3312-2016 (No. 4) is used for testing the purity of gold, that is, the equivalent concentration deduction method is directly combined with the internal standard method, and the purity of the gold sample is determined by using an ICP-AES spectrometer, and the other aspects are the same as those of Example 1, which will not be repeated here. The gold purity determination results of Experimental Example 2 and the reference values of the national standard sample are compared and shown in Table 4.

[0075] Table 4 Comparison of gold purity determination results and reference values of Experimental Example 2 As can be seen from the comparison, the deviation between the impurity content of the gold sample determined in Experimental Example 2 and the reference value is not more than 0.0004%, and the final calculated gold purity is the same as the reference value.

[0076] Experimental Example 3 The difference between Experimental Example 3 and Example 1 is that the purity of the silver sample obtained in Example 1 step SS3 is tested according to the determination method in the national standard GB / T 11067.1-2006 "Silver Chemical Analysis Method Determination of Silver Content Silver Chloride Precipitation-Flame Atomic Absorption Spectrometry". The comparison of the silver purity determination results of Experimental Example 3 and Example 1 is shown in Table 5.

[0077] Table 5 Comparison of silver purity determination results of Experimental Example 3 and Example 1 As can be seen from the comparison, the purity of the silver sample determined in Experimental Example 1 is very close to the purity of the silver sample determined according to the determination method in the national standard GB / T 11067.1-2006, with only a difference of 0.001%.

[0078] Experimental Example 4 The difference between Experimental Example 4 and Example 2 is that the purity of the silver sample obtained in Example 2 step SS3 is tested according to the determination method in the national standard GB / T 11067.1-2006 "Silver Chemical Analysis Method Determination of Silver Content Silver Chloride Precipitation-Flame Atomic Absorption Spectrometry". The comparison of the silver purity determination results of Experimental Example 4 and Example 2 is shown in Table 6.

[0079] Table 6 Comparison of silver purity determination results of Experimental Example 4 and Example 1 As can be seen from the comparison, the purity of the silver sample determined in Experimental Example 1 is very close to the purity of the silver sample determined according to the determination method in the national standard GB / T 11067.1-2006, with only a difference of 0.002%.

[0080] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the national standard sample GSB 04-3312-2016 (No. 1) is used to determine the purity of gold, and the silver sample obtained in Example 1 step SS3 is used to determine the purity of silver. Only the internal standard method is used, not the equivalent concentration deduction method, and the purity of the gold sample and the silver sample is determined by ICP-AES spectrometer. Among them, the preparation method of solution A2 is to transfer 2.5 mL aqua regia to a 25 mL volumetric flask with water, add 1.00 mL of yttrium internal standard solution with a concentration of 50 ug / mL, and dilute to volume with water, mix well. The preparation method of solution B2 is to transfer 5 mL of nitric acid to a 50 mL volumetric flask with water, add 2.00 mL of yttrium internal standard solution with a concentration of 50 ug / mL, and dilute to volume with water, mix well. That is, solution A2 does not contain high-purity gold sample, and solution B2 does not contain high-purity silver sample.

[0081] The gold purity determination results of Comparative Example 1 are shown in Table 7.

[0082] Table 7 Comparison of gold purity determination results of Comparative Example 1 with reference values ω measured in Comparative Example 1 Au = 99.596%, which is 0.317% lower than the reference value.

[0083] The silver purity determination results of Comparative Example 1 are shown in Table 8.

[0084] Table 8 Impurity element content in silver sample measured in Comparative Example 1 It is calculated that ω Ag = 99.850%, which is 0.051% lower than 99.901% measured in Example 1.

[0085] It can be seen that the determination result of arsenic in the gold sample of Comparative Example 1 is 14.7 times higher than the reference value, and the determination result of iridium is 194 times higher than the reference value, resulting in a serious underestimation of the gold purity. The detection content of arsenic in the silver sample of Comparative Example 1 is 0.0356%, while the content of arsenic in the silver sample of Example 1 is lower than the detection limit, resulting in an underestimation of the silver purity. This is because the impurity elements arsenic and iridium in gold have a serious positive interference on the test. In the test solution, a large amount of matrix elements (gold and / or silver) changes the physical and chemical environment of the plasma, improves the energy transmission and utilization environment, and also suppresses the ionization of impurity elements (such as arsenic and iridium) in the sample, so that these elements exist in the form of atoms, thereby enhancing the atomic emission spectrum signal of these elements, resulting in an overestimation of the determination results of these elements. Even if the internal standard method is used for correction, since the matrix effect does not suppress the ionization of yttrium, the arsenic and iridium elements in gold will not be corrected by the internal standard element, and the determination results will still be overestimated. At the same time, only the internal standard method is used for determination, since the matrix of the sample solution and the blank solution is different, the atomization efficiency produced is inconsistent, which will also cause a certain deviation in the determination results.

[0086] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the national standard sample GSB 04-3312-2016 (No. 1) is used to determine the purity of gold, and the silver sample obtained in step SS3 of Example 1 is used to determine the purity of silver. Only the equivalent concentration deduction method is used, and the internal standard method is not used. The purity of the gold sample and the silver sample is determined by ICP-AES spectrometer. Among them, the preparation method of solution A2 is that 0.2500 g of high-purity gold sample is placed in a polytetrafluoroethylene beaker, 2.5 mL of aqua regia is added, heated to completely dissolve the gold, and the solution is transferred to a 25 mL volumetric flask with water, and then diluted to volume with water and mixed. The preparation method of solution B2 is that 0.5000 g of high-purity silver sample is placed in a polytetrafluoroethylene beaker, 5 mL of nitric acid is added, heated to completely dissolve the silver, and the solution is transferred to a 50 mL volumetric flask with water, and then diluted to volume with water and mixed. That is, neither solution A2 nor solution B2 contains yttrium internal standard.

[0087] The gold purity determination results of Comparative Example 2 are shown in Table 9.

[0088] Table 9 Comparison of gold purity determination results of Comparative Example 2 with reference values The ω of Comparative Example 2 is measured Au =99.895%, which is 0.018% lower than the reference value.

[0089] The silver purity determination results of Comparative Example 2 are shown in Table 10.

[0090] Table 10 Impurity element content in the silver sample measured in Comparative Example 2 It is calculated that ω Ag =99.912%, which is 0.011% higher than 99.901% measured in Example 1.

[0091] It can be seen from the comparison that the silver purity measured in Comparative Example 2 is too high, and the gold purity is too low. This is because the solubility of the solid (gold and / or silver) in the sample matrix of Comparative Example 2 changes the viscosity and surface tension of the solution, forming non-uniform aerosol droplets in the sample, resulting in unstable signals, and the signal is enhanced or weakened, that is, the signal drift phenomenon occurs. The equivalent concentration deduction method is used, and the signal drift of the measured element cannot be corrected, resulting in unstable test results and deviation.

[0092] Comprehensive analysis of Comparative Example 1-2 and Example 1 shows that the addition of yttrium internal standard can correct the signal drift of the element to be measured, and improve the stability of the test results. However, due to the matrix effect, the ionization of yttrium is not suppressed, and the elements of arsenic and iridium are difficult to be corrected by the internal standard element, resulting in the measured concentration of arsenic and iridium being too high. The equivalent concentration deduction method can ensure the consistency of the matrix of the sample solution and the blank solution, not only ensuring the consistency of the atomization efficiency, but also offsetting the part of the deviation of the measured concentration of arsenic and iridium elements caused by the matrix effect. Therefore, the combination of the equivalent concentration deduction method and the internal standard method is beneficial to further improve the test precision.

[0093] In summary, the application provides a method for determining the mass and purity of gold and silver in gold and silver commemorative coins. The gold and silver in the gold and silver commemorative coins are separated to obtain a gold sample and a silver sample. The mass of the gold sample is m1g, and the mass of the silver sample is m2g. Finally, the equivalent concentration deduction method and the internal standard method are combined, and the purity of the gold sample and / or the silver sample is determined by an ICP-AES spectrometer. In the application, the gold and silver commemorative coins are placed in an inert gas atmosphere for high-temperature treatment, and then treated with dilute hydrochloric acid at high temperature for multiple times, and then washed with ammonium nitrate solution to fully remove the paint layer on the surface of the commemorative coin and the aluminum plating layer between gold and silver. This method can avoid damaging the appearance shape of the gold and silver sample, and at the same time, it will not introduce new impurities, and effectively improve the test accuracy. The application also combines the equivalent concentration deduction method with the internal standard method, and uses the equivalent concentration deduction method to reduce the positive interference of the matrix effect on the determination of the content of impurity elements such as arsenic and iridium, solves the problem that the internal standard method cannot correct the impurity elements such as arsenic and iridium, and effectively improves the test precision. The purity of the gold sample determined by the application only differs by 0.001% from the reference value, and the purity of the silver sample determined by the application only differs by 0.002% from the determination result according to the national standard GB / T 11067.1-2006 "Silver Chemical Analysis Method Determination of Silver Content Silver Chloride Precipitation Flame Atomic Absorption Spectrometry".

[0094] It should be noted that the application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role within the scope of the technical solution of the application are all included in the technical scope of the application. In addition, within the scope of the main idea of the application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the elements in the embodiments are also included in the scope of the application.

Claims

1. A method for determining the quality and purity of gold and silver in gold and silver commemorative coins, characterized in that: The gold and silver in the gold and silver commemorative coins are separated to obtain a gold sample and a silver sample, and then the gold sample is weighed to obtain a mass m1g, and the silver sample is weighed to obtain a mass m2g. Finally, the equivalent concentration subtraction method is combined with the internal standard method, and the purity of the gold sample and / or the silver sample is determined by an ICP-AES spectrometer; wherein, Combining the equivalent concentration subtraction method with the internal standard method to determine the purity of the gold sample comprises the following steps: S1, prepare solution A1, solution A2 and standard solution A respectively 3n The solution A1 contains yttrium internal standard and m3g of the gold sample, the solution A2 contains yttrium internal standard and m3g of high-purity gold sample, and the standard solution A3 contains yttrium internal standard and various impurity elements; S2, using ICP-AES spectrometer to measure the concentration of impurity elements in the solution A1, recorded as C 1i , determine the concentration of impurity elements in the solution A2, recorded as C 2i ; S3, calculate the purity ω of the gold sample Au ; Combining the equivalent concentration subtraction method with the internal standard method to determine the purity of the silver sample comprises the following steps: S4, prepare solution B1, solution B2 and standard solution B respectively 3n The solution B1 contains yttrium internal standard and m4g of the silver sample, the solution B2 contains yttrium internal standard and m4g of high-purity silver sample, and the standard solution B3 contains yttrium internal standard and various impurity elements; S5, using ICP-AES spectrometer to measure the concentration of impurity elements in the solution B1, recorded as D 1j , determine the concentration of impurity elements in the solution B2, and record it as D 2j ; S6, calculate the purity ω of the silver sample Ag .

2. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 1, characterized in that: The steps of preparing the solution A1 and the solution A2 include dissolving the sample in aqua regia under heating conditions, then adding yttrium internal standard solution, and finally diluting with water; The steps of preparing the solution B1 and the solution B2 include dissolving the sample with nitric acid under heating conditions, then adding yttrium internal standard solution, and finally diluting with water; Prepare the standard solution A 3n The steps include mixing an yttrium internal standard solution, a mixed standard solution A4 containing multiple impurity elements, and aqua regia, and then diluting with water; Prepare the standard solution B 3n The steps include mixing an yttrium internal standard solution, a mixed standard solution B4 containing multiple impurity elements, and nitric acid, and then diluting with water.

3. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 2, characterized in that: The standard solution A 31 ,...,A 3n The concentration of impurity elements in the standard solution B increases in an arithmetic progression. 31 ,...,B 3n The concentration of impurity elements in the mixture increases in an arithmetic progression.

4. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 3, characterized in that: n is a natural integer of 1-5; the standard solution A 31 、A 32 、A 33 、A 34 、A 35 The concentrations of impurity elements in the standard solution B were 0 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, and 10.0 μg / mL, respectively. 31 、B 32 、B 33 、B 34 、B 35 The concentrations of impurity elements in the solution were 0 μg / mL, 1.0 μg / mL, 3.0 μg / mL, 5.0 μg / mL, and 10.0 μg / mL, respectively.

5. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 2, characterized in that: The solution A1, the solution A2, the standard solution A 3n , the solution B1, the solution B2 and the standard solution B 3n The yttrium concentration in the mixed standard solution is 1.5-2.5 μg / mL; the impurity elements contained in the mixed standard solution A4 include Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, and Na; the impurity elements contained in the mixed standard solution B4 include Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, and Na; the purity of the high-purity gold sample and the high-purity silver sample is greater than or equal to 99.999%.

6. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 1, characterized in that: The solution A1, the solution A2 and the standard solution A 3n The volumes of the gold samples are equal and are both recorded as V1. The purity of the gold sample is ω Au The calculation formula is: ,in, ∑(C 1i -C 2i ) represents the sum of the concentrations of all impurity elements after deducting the blank; i is a natural integer from 1 to 23, corresponding to the impurity elements Ag, Al, As, Bi, Cd, Cr, Cu, Ir, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Sn, Te, Ti, Fe, Mg, Zn, and Na, respectively.

7. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 1, characterized in that: The solution B1, the solution B2 and the standard solution B 3n The volumes of the silver samples are equal and are both recorded as V2. The purity of the silver sample is ω Ag The calculation formula is: ,in, ∑(D 1j -D 2j ) represents the sum of the concentrations of all impurity elements after deducting the blank; j is a natural integer from 1 to 20, corresponding to the impurity elements Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Sb, Se, Sn, Te, Ti, Zn, and Na, respectively.

8. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 1, characterized in that: The gold and silver commemorative coins contain an aluminum coating; and separating the gold and silver in the gold and silver commemorative coins comprises the following steps: SS1, placing the gold and silver commemorative coins in an inert gas atmosphere, heating them to a first temperature and treating them for a first time, to obtain a gold sample P1 with aluminum attached to the surface and a silver sample P2 with aluminum attached to the surface; SS2, placing the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface obtained in step SS1 in dilute hydrochloric acid, heating them to a second temperature and treating them for a second time, removing the solution, and repeating the treatment with dilute hydrochloric acid 2-4 times to obtain a gold sample P3 and a silver sample P4; SS3, washing the gold sample P3 and the silver sample P4 obtained in step SS2 with an ammonium nitrate solution under heating conditions, then washing them with water 3-5 times, and drying to obtain the gold sample and the silver sample.

9. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 8, characterized in that: The first temperature is 660-700° C., and the first time is 15-30 minutes; the second temperature is 200-250° C., and the second time is the time required to dissolve the aluminum on the surface of the gold sample P1 with aluminum attached to the surface and the silver sample P2 with aluminum attached to the surface; The gold sample P3 and the silver sample P4 were washed with ammonium nitrate solution for 5-10 minutes.

10. The method for determining the quality and purity of gold and silver in gold and silver commemorative coins according to claim 8, characterized in that: The concentration of the dilute hydrochloric acid is 25-33%; the concentration of the ammonium nitrate solution is 20-25 g / L.

Images