Dissolving method and quantitative analysis method of precious metal

Abstract

The invention provides a precious metal dissolving method and quantitative analysis method, which comprises the following steps: S1, carrying out first heating on a first mixture to obtain a first product; the first mixture comprises borosilicate glass, aqua regia and a hydrofluoric acid solution; the temperature of the heat preservation stage of the first heating is 80-150 DEG C; s2, performing second heating on the second mixture to obtain a second product; the second mixture comprises the first product and disulfate; the temperature of the heat preservation stage of the second heating is 600 DEG C or above; s3, performing third heating on the third mixture to obtain a third product; the third mixture comprises a second product and an acid solution; the temperature of the heat preservation stage of the third heating is 80 DEG C or above. The precious metal dissolving method can effectively dissolve the precious metal in the glass into the solution, and the quantitative method has excellent accuracy and precision.

Description

Technical Field

[0001] The present invention relates to a method for dissolving precious metals and a method for quantitative analysis. Background Art

[0002] As a clean energy source, nuclear energy has been widely applied and developed. However, during the utilization of nuclear energy, a large amount of radioactive nuclear waste will inevitably be generated. Glass can contain a wide variety of elements and has long-term chemical corrosion resistance, making it an ideal technology for the solidification of high-level nuclear waste. Borosilicate glass is considered the preferred material for solidifying high-level radioactive waste. The introduction of boron oxide greatly reduces the glass formation temperature and improves the durability of the glass within an appropriate composition range. Platinum group metals (rhodium, palladium, ruthenium), as nuclear fission products, have attracted particular attention during the nuclear waste reprocessing process due to their complex chemical behavior. Currently, the research on the glass solidification process of nuclear waste started relatively late, and the research on precious metals rhodium, palladium, and ruthenium in glass solids has just begun. To understand the behavior of rhodium, palladium, and ruthenium in the glass solidification process, it is particularly important to study the distribution and accurate quantitative analysis of rhodium, palladium, and ruthenium in glass solidified bodies.

[0003] Platinum group elements are extremely rare but have excellent properties, and are also an important research content in the field of precious metal metallurgy. Due to the extremely stable properties of platinum group elements, especially rhodium, which has strong resistance to chemical reagent corrosion and hardly undergoes obvious chemical reactions with strong acids and strong bases, its dissolution has always been a difficult problem in the extraction, refining, and chemical analysis of platinum group metals.

[0004] Currently, the research on precious metals rhodium and palladium mainly focuses on the recycling of precious metals, and the dissolution methods mainly target the recycling aspect. Since the recycling of precious metals mainly considers the extraction rate, complex processes, repeated extractions, and increasing the sample amount can be used to achieve a higher extraction rate. However, in terms of quantitative analysis, the processed samples usually do not exceed one gram. If the process is complex and repeated extractions are carried out, not only will the analysis time be greatly increased, but also there are many uncertain factors such as a large proportion of sample loss and introduction of interfering impurities during repeated extractions, which greatly increases the analysis error and makes it impossible to accurately quantify.

[0005] In view of the fact that there is currently no quantitative method applicable to the content of rhodium and palladium in borosilicate glass, it is very necessary to develop a rapid and accurate quantitative analysis method for precious metals rhodium and palladium in borosilicate glass, especially for the analysis of the precious metal content in glass with a relatively high precious metal content. Summary of the Invention

[0006] To solve the above problems in the prior art, the present invention provides a method for dissolving precious metals and a method for quantitative analysis. The method for dissolving precious metals can effectively dissolve precious metals in glass into a solution, and the quantitative analysis method has excellent accuracy and precision.

[0007] The present invention solves the above technical problems through the following technical solutions.

[0008] The present invention provides a method for dissolving precious metals, which comprises the following steps:

[0009] S1. Perform first heating on a first mixture to obtain a first product; the first mixture comprises borosilicate glass, aqua regia and hydrofluoric acid solution; the temperature in the heat preservation stage of the first heating is 80-150°C;

[0010] S2. Perform second heating on a second mixture to obtain a second product; the second mixture comprises the first product and bisulfate; the temperature in the heat preservation stage of the second heating is above 600°C;

[0011] S3. Perform third heating on a third mixture to obtain a third product; the third mixture comprises the second product and acid solution; the temperature in the heat preservation stage of the third heating is above 80°C.

[0012] In the present invention, the borosilicate glass has its conventional meaning in the art, and the borosilicate glass comprises base glass and / or glass solidified body. The base glass is based on silicon dioxide and contains certain amounts of boron oxide, sodium oxide and other components; the glass solidified body is based on silicon dioxide, and in addition to containing certain amounts of boron oxide, sodium oxide and other components, according to the specific nuclear waste components and glass solidification requirements, also comprises other components such as calcium oxide, aluminum oxide, zirconium oxide and rare earth oxide.

[0013] In the present invention, the precious metals in the borosilicate glass can occupy the original lattice positions of boron and silicon in the borosilicate glass and form chemical bonds with boron and silicon, and these chemical bonds enable the precious metals to stably exist in the borosilicate glass and are difficult to dissolve.

[0014] In the present invention, in step S1, preferably, the borosilicate glass comprises boron element, silicon element, sodium element, rhodium element and palladium element.

[0015] Among them, preferably, the mass percentage of boron element in the borosilicate glass is 2.5% or more, more preferably 3.5% or more, for example 4%.

[0016] Among them, preferably, the mass percentage of silicon element in the borosilicate glass is 18% or more, for example 23% or 30%.

[0017] Among them, preferably, the mass percentage of rhodium element in the borosilicate glass is 0.01%-6%, for example 0.5%, 0.03% or 5.2%.

[0018] Among them, preferably, the mass percentage of the palladium element in the borosilicate glass is 0.01% - 25%, for example, 0.03%, 0.5% or 21%.

[0019] Among them, preferably, the mass percentage of the sodium element in the borosilicate glass is more than 0.8%, more preferably 5% - 10%, and even more preferably 5% - 6%.

[0020] Among them, preferably, the borosilicate glass further includes a calcium element.

[0021] Among them, preferably, the mass percentage of the calcium element in the borosilicate glass is 2% - 10%, more preferably 5% - 10%.

[0022] In a specific embodiment of the present invention, the mass percentage of the calcium element in the borosilicate glass is 2.1%.

[0023] Among them, preferably, the borosilicate glass further includes an aluminum element.

[0024] Among them, preferably, the mass percentage of the aluminum element in the borosilicate glass is 1% - 7%, more preferably 1% - 5%, for example, 4%.

[0025] Among them, preferably, the borosilicate glass further includes a zirconium element.

[0026] Among them, preferably, the mass percentage of the zirconium element in the borosilicate glass is 1% - 5%, for example, 1.9% or 4%.

[0027] Among them, preferably, the borosilicate glass further includes a molybdenum element.

[0028] Among them, preferably, the mass percentage of the molybdenum element in the borosilicate glass is 1% - 5%, for example, 1.5% or 4%.

[0029] Among them, preferably, the borosilicate glass further includes rare earth elements, and the rare earth elements include one or more of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), scandium (Sc) and yttrium (Y).

[0030] Among them, preferably, the mass percentage of the rare earth elements in the borosilicate glass is 1% - 10%, for example, 2%.

[0031] In some specific embodiments of the present invention, the rare earth elements are cerium and yttrium.

[0032] Among them, preferably, the cerium accounts for 0.5%-1% of the mass of the borosilicate glass.

[0033] Among them, preferably, the yttrium accounts for 0.5%-1% of the mass of the borosilicate glass.

[0034] In a specific embodiment of the present invention, the borosilicate glass further includes barium element.

[0035] Among them, preferably, the barium element accounts for 1.9% of the mass of the borosilicate glass.

[0036] In a specific embodiment of the present invention, the borosilicate glass further includes magnesium element.

[0037] Among them, preferably, the magnesium element accounts for 1.5% of the mass of the borosilicate glass.

[0038] In a specific embodiment of the present invention, the borosilicate glass further includes strontium element.

[0039] Among them, preferably, the strontium element accounts for 1% of the mass of the borosilicate glass.

[0040] In a specific embodiment of the present invention, the borosilicate glass further includes zinc element.

[0041] Among them, preferably, the zinc element accounts for 2% of the mass of the borosilicate glass.

[0042] In a specific embodiment of the present invention, the borosilicate glass further includes silver element.

[0043] Among them, preferably, the silver element accounts for 2% of the mass of the borosilicate glass.

[0044] In some specific embodiments of the present invention, the elements in the borosilicate glass exist in the form of oxides.

[0045] In the present invention, in step S1, the meaning of aqua regia is the conventional meaning in the art, that is, a mixture composed of concentrated hydrochloric acid (HCl) and concentrated nitric acid (HNO3) in a volume ratio of 3:1.

[0046] In the present invention, in step S1, preferably, the concentration of the hydrofluoric acid solution is 30%-50%, for example, 40%.

[0047] Among them, preferably, the solvent of the hydrofluoric acid solution is water.

[0048] In the present invention, in step S1, preferably, the mass ratio of the aqua regia to the borosilicate glass is more than 8:1.

[0049] In the present invention, in step S1, preferably, the mass ratio of the hydrofluoric acid solution to the borosilicate glass is 1:1 or more.

[0050] In the present invention, those skilled in the art generally understand that the first heating sequentially includes a heating-up stage and a heat-preservation stage.

[0051] In the present invention, in step S1, preferably, the temperature in the heat-preservation stage of the first heating is 100 - 150 °C.

[0052] In the present invention, in step S1, preferably, the heating-up rate in the heating-up stage of the first heating is 1 - 3 °C / min.

[0053] In the present invention, in step S1, preferably, the time in the heat-preservation stage of the first heating is 3 - 6 h, for example, 4 h.

[0054] In some specific embodiments of the present invention, the borosilicate glass can be formed after being pulverized, and the pulverization method can be conventional in the art, for example, grinding.

[0055] In the present invention, in step S1, preferably, the D50 particle size of the borosilicate glass is 75 μm or less.

[0056] In some specific embodiments of the present invention, the first heating can be carried out in a crucible.

[0057] Among them, the crucible is, for example, a ceramic crucible or a platinum crucible.

[0058] In the present invention, in step S2, preferably, the mass ratio of the bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example, 7.8:1, 8.4:1 or 12:1.

[0059] In the present invention, in step S2, preferably, the bisulfate is sodium bisulfate and / or potassium bisulfate.

[0060] Among them, preferably, the mass ratio of the sodium bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example, 7.8:1, 8.4:1 or 12:1.

[0061] Among them, preferably, the mass ratio of the sodium bisulfate to the rhodium element in the borosilicate glass is 77:1 or more, more preferably 150:1 or more, still more preferably 162:1 or more, preferably 200:1 or more, for example, 231:1, 2400:1 or 40000:1.

[0062] Among them, preferably, the mass ratio of sodium bisulfate to palladium element in the borosilicate glass is 19:1 or more, more preferably 37:1, still more preferably 40:1, preferably 50:1 or more, for example 57:1, 95:1, 2400:1 or 40000:1.

[0063] Among them, preferably, the mass ratio of potassium bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example 7.8:1, 8.4:1 or 12:1.

[0064] Among them, preferably, the mass ratio of potassium bisulfate to rhodium element in the borosilicate glass is 200:1 or more.

[0065] Among them, preferably, the mass ratio of potassium bisulfate to palladium element in the borosilicate glass is 50:1 or more.

[0066] In the present invention, those skilled in the art generally understand that the second heating sequentially includes a heating-up stage and a heat-preservation stage.

[0067] In the present invention, in step S2, preferably, the temperature of the heat-preservation stage of the second heating is 600 - 650 °C.

[0068] In the present invention, in step S2, preferably, the heating rate of the heating-up stage of the second heating is 1.5 - 2.5 °C / min, for example 1.8 °C / min.

[0069] In the present invention, in step S2, preferably, the time of the heat-preservation stage of the second heating is 6 - 8 h.

[0070] In some specific embodiments of the present invention, the second heating can be carried out in a muffle furnace.

[0071] In the present invention, the meaning of the acid solution is a solution showing acidity.

[0072] In the present invention, in step S3, preferably, the acid solution is one or more of hydrochloric acid, sulfuric acid and nitric acid.

[0073] Among them, preferably, the mass concentration of the hydrochloric acid is 5% - 10%.

[0074] Among them, preferably, the mass concentration of the nitric acid is 5% - 10%.

[0075] Among them, preferably, the mass concentration of the sulfuric acid is 5% - 10%.

[0076] In the present invention, in step S3, preferably, the mass ratio of the acid solution to the second product is (15 - 50):1, more preferably (15 - 30):1, for example, 25:1 or 50:1.

[0077] In the present invention, those skilled in the art generally understand that the third heating sequentially includes a temperature rising stage and a heat preservation stage.

[0078] In the present invention, in step S3, preferably, the temperature in the heat preservation stage of the third heating is 80 - 100 °C.

[0079] In the present invention, in step S3, preferably, the heating rate in the temperature rising stage of the third heating is 1 - 3 °C / min.

[0080] In the present invention, in step S3, preferably, the time in the heat preservation stage of the third heating is 1 - 2 h.

[0081] In the present invention, adding an acid solution in step S3 can dissolve the precious metals in the second product into the solution of the third product. Using an acid solution can dissolve other compounds except precious metals, preventing the adsorption and sedimentation of precious metals due to the presence of a large amount of other insoluble substances. In addition, precious metal (especially rhodium and palladium) compounds are also more stable in acidic solutions.

[0082] In the present invention, the inventors have found through a large number of studies that for the borosilicate glass in which it is difficult to dissolve precious metals in the present invention, using aqua regia and hydrofluoric acid solution and selecting a temperature of 80 - 150 °C to destroy the structure of the borosilicate glass, so that precious metals can be released from the borosilicate glass, but not all released after the first heating. That is, after the first heating, only a small amount of precious metals in the borosilicate glass are dissolved in the solution, and most precious metals still exist in the form of solids in the borosilicate glass solid. After the second heating, the precious metals (especially rhodium and palladium) in the borosilicate glass can all be converted into easily soluble sulfate forms. After the third heating, the third product is a solution, and the third heating can convert all the easily soluble precious metal sulfates into the third product that is easy to detect the content, that is, the mass ratio of the precious metal elements in the third product to the precious metal elements in the borosilicate glass is 100%. For example, the mass ratio of rhodium elements in the third product to the rhodium elements in the borosilicate glass is 100%, and the mass ratio of palladium elements in the third product to the palladium elements in the borosilicate glass is 100%.

[0083] The present invention provides a method for quantitative analysis of precious metals, which includes the following steps: testing and analyzing the third product obtained by using the above precious metal dissolution method.

[0084] The above-mentioned method for dissolving precious metals can convert all precious metal elements in borosilicate glass into forms that are easy to measure, ensuring that all precious metal elements in borosilicate glass can be detected, and improving the accuracy and precision of the detection method.

[0085] In the present invention, the testing is preferably carried out by inductively coupled plasma emission spectrometry and / or inductively coupled plasma mass spectrometry.

[0086] In the present invention, preferably, before the testing and analysis, there is also a step of diluting the third product.

[0087] Among them, the dilution factor is not particularly limited and can be determined according to the actual situation.

[0088] In the present invention, the quantitative analysis method of the precious metals preferably further includes the step of preparing a standard series calibration solution.

[0089] Among them, when the testing is carried out by inductively coupled plasma emission spectrometry, the concentration of each element in the standard series calibration solution is preferably 0 - 10 mg / L.

[0090] Among them, when the testing is carried out by inductively coupled plasma mass spectrometry, the concentration of each element in the standard series calibration solution is preferably 0 - 100 μg / L.

[0091] On the basis of conforming to the common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0092] The reagents and raw materials used in the present invention are all commercially available.

[0093] The positive and progressive effects of the present invention are as follows:

[0094] The method for dissolving precious metals and the quantitative analysis method of the present invention fill the gap in the analysis of the content of precious metals in borosilicate glass, can effectively release all precious metals in the glass and convert them into products in which the content is easy to detect, can simultaneously and rapidly detect the contents of various precious metal elements, and have excellent accuracy and precision. Detailed Embodiments

[0095] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the examples described herein. The experimental methods without specific conditions noted in the following examples are carried out according to conventional methods and conditions, or are selected according to the product specifications.

[0096] Example 1

[0097] The types of constituent elements and the content of each element of the borosilicate glass in Example 1 are as shown in Table 1 below:

[0098] Table 1

[0099]

[0100] The above borosilicate glass was crushed to a D50 particle size of 75 μm.

[0101] The method for dissolving precious metals in Example 1 includes the following steps:

[0102] S1. The first mixture was first heated in a ceramic crucible to obtain a first product; the first mixture included 0.5003 g of borosilicate glass, 4 mL of aqua regia (with a mass of 40 g and a mass ratio to the borosilicate glass of 8:1), and 0.5 mL of a 40% hydrofluoric acid aqueous solution (the mass ratio of hydrofluoric acid in the hydrofluoric acid solution to the mass of the borosilicate glass was 1:1); the temperature in the heat preservation stage of the first heating was 100 °C, the heating rate in the heating-up stage of the first heating was 1 °C / min, and the time in the heat preservation stage of the first heating was 4 h;

[0103] S2. The second mixture was second heated in a muffle furnace to obtain a second product; the second mixture included the above first product and 6.001 g of sodium bisulfate (the mass ratio of sodium bisulfate to the borosilicate glass was 12:1, the mass ratio of sodium bisulfate to the rhodium element in the borosilicate glass was 231:1, and the mass ratio of sodium bisulfate to the palladium element in the borosilicate glass was 57:1); the temperature in the heat preservation stage of the second heating was 650 °C; the heating rate in the heating-up stage of the second heating was 1.8 °C / min, and the time in the heat preservation stage of the second heating was 6 h;

[0104] S3. The third mixture was third heated to obtain a third product; the third mixture included 4 g of the above second product and 200 g of a 5% hydrochloric acid; the temperature in the heat preservation stage of the third heating was 100 °C, the heating rate in the heating-up stage of the third heating was 1 °C / min, and the time in the heat preservation stage of the third heating was 1 h.

[0105] The method for quantitative analysis of precious metals in Example 1 includes the following steps:

[0106] The above third product was diluted by a dilution factor of 100 times, and after dilution, it was tested using an inductively coupled plasma spectrometer.

[0107] Among them, the standard series calibration solution is prepared by the following steps: Using commercially available standard stock solutions of rhodium and palladium elements with a concentration of 1000 mg / L, prepare standard solutions with a concentration range of 0 - 10 mg / L; Test the standard series calibration solutions and blank solutions on an inductively coupled plasma spectrometer. Using the signal intensities of rhodium and palladium elements in the standard series calibration solutions as the ordinate and the concentrations of each element in the standard series calibration solutions as the abscissa, plot a calibration curve; Test the third product on an inductively coupled plasma spectrometer to obtain the signal intensities of rhodium and palladium elements, and substitute them into the calibration curve to calculate the final contents of rhodium and palladium elements.

[0108] Example 2

[0109] The types of constituent elements and the content of each element of the borosilicate glass in Example 2 are as shown in Table 2 below:

[0110] Table 2

[0111]

[0112] The above borosilicate glass is crushed to a D50 particle size of 75 μm.

[0113] The method for dissolving precious metals in Example 2 includes the following steps:

[0114] S1. Perform first heating on the first mixture in a ceramic crucible to obtain a first product; The first mixture includes 0.4996 g of borosilicate glass, 4 mL (with a mass of 40 g, and the mass ratio to the borosilicate glass is 8:1) of aqua regia, and 1 mL of an aqueous hydrofluoric acid solution with a mass concentration of 40% (the mass ratio of hydrofluoric acid in the hydrofluoric acid solution to the borosilicate glass is 1:1); The temperature in the heat preservation stage of the first heating is 100 °C, the heating rate in the heating-up stage of the first heating is 3 °C / min, and the time in the heat preservation stage of the first heating is 4 h;

[0115] S2. Perform second heating on the second mixture in a muffle furnace to obtain a second product; The second mixture includes the above first product and 6.0018 g of sodium bisulfate (the mass ratio of sodium bisulfate to the borosilicate glass is 12:1, the mass ratio of sodium bisulfate to rhodium element in the borosilicate glass is 40000:1, and the mass ratio of sodium bisulfate to palladium element in the borosilicate glass is 40000:1); The temperature in the heat preservation stage of the second heating is 600 °C; The heating rate in the heating-up stage of the second heating is 2.5 °C / min, and the time in the heat preservation stage of the second heating is 6 h;

[0116] S3. Perform a third heating on the third mixture to obtain a third product; the third mixture includes the above-mentioned 4 g of the second product and 100 g of hydrochloric acid with a mass concentration of 5%; the temperature in the heat preservation stage of the third heating is 100 °C, the heating rate in the temperature rising stage of the third heating is 3 °C / min, and the time in the heat preservation stage of the third heating is 1 h.

[0117] The method for quantitative analysis of precious metals in Example 2 includes the following steps:

[0118] Dilute the above-mentioned third product by a dilution factor of 20 times, and after dilution, test it using an inductively coupled plasma mass spectrometer.

[0119] Among them, the standard series calibration solution is prepared by the following steps: Use commercially available standard stock solutions of rhodium and palladium elements with a concentration of 10 mg / L to prepare standard solutions with a concentration of 0 - 100 μg / L; Test the standard series calibration solution and the blank solution on an inductively coupled plasma mass spectrometer. Take the signal intensities of rhodium and palladium elements in the standard series calibration solution as the ordinate and the concentrations of each element in the standard series calibration solution as the abscissa to make a calibration curve; Test the third product on an inductively coupled plasma mass spectrometer to obtain the signal intensities of rhodium and palladium elements, and substitute them into the calibration curve to calculate the final contents of rhodium and palladium elements.

[0120] Example 3

[0121] The types of constituent elements and the contents of each element of the borosilicate glass in Example 3 are as shown in Table 3 below:

[0122] Table 3

[0123]

[0124] Crush the above-mentioned borosilicate glass into a D50 particle size of 75 μm.

[0125] The method for dissolving precious metals and the method for quantitative analysis of precious metals in Example 3 are the same as those in Example 1. Among them, the mass ratio of sodium bisulfate to borosilicate glass is 12:1, the mass ratio of sodium bisulfate to rhodium element in borosilicate glass is 2400:1, and the mass ratio of sodium bisulfate to palladium element in borosilicate glass is 2400:1.

[0126] Example 4

[0127] The composition of the borosilicate glass in Example 4 is the same as that in Example 1.

[0128] In the method for dissolving noble metals in Example 4, in step S2, the second mixture includes 2 g of sodium bisulfate, that is, the mass ratio of sodium bisulfate to borosilicate glass is 4:1 (the mass ratio of rhodium element in sodium bisulfate to borosilicate glass is 77:1, and the mass ratio of palladium element in sodium bisulfate to borosilicate glass is 19:1). Other conditions are the same as those in Example 1.

[0129] The method for quantitative analysis of noble metals in Example 4 is the same as that in Example 1.

[0130] Example 5

[0131] The composition of the borosilicate glass in Example 5 is the same as that in Example 1.

[0132] In the method for dissolving noble metals in Example 5, in step S2, the second mixture includes 10 g of sodium bisulfate, that is, the mass ratio of sodium bisulfate to borosilicate glass is 20:1 (the mass ratio of rhodium element in sodium bisulfate to borosilicate glass is 385:1, and the mass ratio of palladium element in sodium bisulfate to borosilicate glass is 95:1). Other conditions are the same as those in Example 1.

[0133] The method for quantitative analysis of noble metals in Example 5 is the same as that in Example 1.

[0134] Example 6

[0135] The composition of the borosilicate glass in Example 6 is the same as that in Example 1.

[0136] In the method for dissolving noble metals in Example 6, in step S2, the second mixture includes 3.9 g of sodium bisulfate, that is, the mass ratio of sodium bisulfate to borosilicate glass is 7.8:1 (the mass ratio of rhodium element in sodium bisulfate to borosilicate glass is 150:1, and the mass ratio of palladium element in sodium bisulfate to borosilicate glass is 37:1). Other conditions are the same as those in Example 1.

[0137] The method for quantitative analysis of noble metals in Example 6 is the same as that in Example 1.

[0138] Example 7

[0139] The composition of the borosilicate glass in Example 7 is the same as that in Example 1.

[0140] In the method for dissolving noble metals in Example 7, in step S2, the second mixture includes 4.2 g of sodium bisulfate, that is, the mass ratio of sodium bisulfate to borosilicate glass is 8.4:1 (the mass ratio of rhodium element in sodium bisulfate to borosilicate glass is 162:1, and the mass ratio of palladium element in sodium bisulfate to borosilicate glass is 40:1). Other conditions are the same as those in Example 1.

[0141] The method for quantitative analysis of noble metals in Example 6 is the same as that in Example 1.

[0142] Comparative Example 1

[0143] The composition of the borosilicate glass in Comparative Example 1 is the same as that in Example 1.

[0144] The method for dissolving the precious metal in Comparative Example 1 includes the following steps:

[0145] S1. Mix 0.5003 g of borosilicate glass, 4 mL (with a mass of 40 g) of aqua regia, and 0.5 mL of a 40% hydrofluoric acid aqueous solution, without performing the first heating, to obtain a first product;

[0146] The conditions of steps S2 and S3 are the same as those in Example 1.

[0147] The method for quantitative analysis of the precious metal in Comparative Example 1 is the same as that in Example 1.

[0148] Comparative Example 2

[0149] The composition of the borosilicate glass in Comparative Example 2 is the same as that in Example 1.

[0150] In the method for dissolving the precious metal in Comparative Example 2, the hydrochloric acid in Example 1 is replaced with water, and the other conditions are the same as those in Example 1.

[0151] The method for quantitative analysis of the precious metal in Comparative Example 2 is the same as that in Example 1.

[0152] Comparative Example 3

[0153] The composition of the borosilicate glass in Comparative Example 3 is the same as that in Example 1.

[0154] The method for dissolving the precious metal in Comparative Example 3 includes the following steps:

[0155] In S1, the temperature in the heat preservation stage of the first heating is 200 °C, the heating rate in the temperature rising stage of the first heating is 1 °C / min, and the time in the heat preservation stage of the first heating is 4 h; the other conditions are the same as those in Example 1.

[0156] The conditions of steps S2 and S3 are the same as those in Example 1.

[0157] The method for quantitative analysis of the precious metal in Comparative Example 3 is the same as that in Example 1.

[0158] Effect Example 1

[0159] 1. Calculation of spike recovery rate: 3.0 mg of rhodium oxide and 20 mg of palladium oxide were added to Examples 1-7 and Comparative Examples 1-3, and the masses of rhodium and palladium were recorded as the added amounts of rhodium and palladium, respectively; the masses of rhodium and palladium in the borosilicate glass of Examples 1-7 and Comparative Examples 1-3 were recorded as the initial amounts of rhodium and palladium (such as 5.2% and 21% in Example 1, respectively); the dissolved and quantitatively analyzed precious metals were obtained by the same steps as in Examples 1-8 and Comparative Examples 1-3 to obtain the measured amounts of rhodium and palladium. The spike recovery rate of rhodium = (measured amount of rhodium - initial amount of rhodium) / added amount of rhodium, and the spike recovery rate of palladium = (measured amount of palladium - initial amount of palladium) / added amount of palladium. The closer the spike recovery rate is to 100%, the higher its accuracy.

[0160] 2. Calculation of precision: The rhodium and palladium contents were tested by the methods of Examples 1-7 and Comparative Examples 1-3. More than 6 samples were measured in parallel, and the measured values were statistically calculated to obtain the relative standard deviation, and the precision of the results was characterized by the relative standard deviation.

[0161] The sample recovery rates and precision results of Examples 1-2 are listed in Table 4 below:

[0162] Table 4

[0163]

[0164] As can be seen from the above table, the dissolution method and quantitative analysis method of the precious metals of the present invention have excellent accuracy and precision. For the spike recovery rate of Rh, it can reach more than 53%, and for Pd, it can reach more than 80%. For the relative standard deviation of Rh, it can reach below 5.3%, and for Pd, it can reach below 4.6%.

[0165] According to the results of Examples 1-3, the mass percentage of sodium element in the borosilicate glass is 5%-10%, which can further make the spike recovery rates of Rh and Pd closer to 100%, and the relative standard deviation can reach below 1.5%, indicating that the mass percentage of sodium element in the borosilicate glass being 5%-10% can further improve the accuracy and precision.

[0166] According to the results of Examples 1, 4-5, the mass ratio of sodium bisulfate to borosilicate glass being (6-16):1 can further improve the accuracy and precision.

[0167] According to the results of Examples 1, 6-7, the mass ratio of sodium bisulfate to rhodium element in the borosilicate glass being above 200:1 and the mass ratio of sodium bisulfate to palladium element in the borosilicate glass being above 50:1 can further improve the accuracy and precision.

[0168] According to the results of Comparative Example 1 and Example 1, it can be seen that Comparative Example 1 does not contain the first heating, resulting in the spike recovery rates of Rh and Pd deviating significantly from 100%, and the relative deviation being higher than 7%. This indicates that without the first heating, accurate and precise measurement of noble metal elements cannot be achieved. This may be because, on the one hand, without the first heating, the structure of the glass cannot be effectively destroyed, so the boron and silicon matrix in the glass cannot be removed, reducing the interference of the matrix on subsequent steps; on the other hand, without the first heating, the first product is in liquid form. After adding sodium bisulfate subsequently, sodium bisulfate directly ionizes in the aqueous solution and cannot play the role of high-temperature melting of acid salts.

[0169] According to the results of Comparative Example 3 and Example 1, it can be seen that the first heating temperature in Comparative Example 3 is too high, causing the spike recovery rates of Rh and Pd to deviate from 100%, and the relative deviation being higher than 4.5%. This indicates that when the first heating temperature is too high, accurate and precise measurement of noble metal elements cannot be achieved. This may be because, for the aqua regia and hydrofluoric acid aqueous solution added in S1, they have a certain boiling point, and too high a temperature may cause the aqua regia and hydrofluoric acid aqueous solution to evaporate, unable to achieve the corresponding effects.

[0170] According to the results of Comparative Example 2 and Example 1, it can be seen that acid solution is not used in S3 of Comparative Example 2, resulting in the spike recovery rates of Rh and Pd deviating from 100%, and the relative deviation being higher than 4.5%. This indicates that without using acid solution, accurate and precise measurement of noble metal elements cannot be achieved. This may be because, under non-acidic conditions, there will be a large amount of other insoluble substances except rhodium and palladium, leading to the adsorption and sedimentation of rhodium and palladium, affecting the test results. In addition, the compounds of elements such as rhodium and palladium are unstable under non-acidic conditions and will also affect the test results.

[0171] The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made according to the claims and the content of the specification of the present invention application fall within the scope of the claims of the present invention patent. The content not described in detail in the present invention is all conventional technical content.

Claims

1. A method for dissolving precious metals, characterized in that, It includes the following steps: S1. Perform a first heating on the first mixture to obtain a first product; the first mixture includes borosilicate glass, aqua regia, and a hydrofluoric acid solution; the temperature in the heat preservation stage of the first heating is 80 - 150 °C; S2. Perform a second heating on the second mixture to obtain a second product; the second mixture includes the first product and a bisulfate; the temperature in the heat preservation stage of the second heating is above 600 °C; S3. Perform a third heating on the third mixture to obtain a third product; the third mixture includes the second product and an acid solution; the temperature in the heat preservation stage of the third heating is above 80 °C.

2. The method for dissolving precious metals according to claim 1, wherein In step S1, the borosilicate glass includes boron, silicon, sodium, rhodium, and palladium; Among them, preferably, the mass percentage of boron in the borosilicate glass is 2.5% or more, more preferably 3.5% or more, for example, 4%; Among them, preferably, the mass percentage of silicon in the borosilicate glass is 18% or more, for example, 23% or 30%; Among them, preferably, the mass percentage of rhodium in the borosilicate glass is 0.01% - 6%, for example, 0.5%, 0.03%, or 5.2%; Among them, preferably, the mass percentage of palladium in the borosilicate glass is 0.01% - 25%, for example, 0.03%, 0.5%, or 21%; Among them, preferably, the mass percentage of sodium in the borosilicate glass is 0.8% or more, more preferably 5% - 10%, and even more preferably 5% - 6%.

3. The method for dissolving precious metals according to claim 2, characterized in that It satisfies one or more of the following conditions: (a) The borosilicate glass further includes calcium; Among them, preferably, the mass percentage of calcium in the borosilicate glass is 2% - 10%, more preferably 5% - 10%; (b) The borosilicate glass further includes aluminum; Among them, preferably, the mass percentage of aluminum in the borosilicate glass is 1% - 7%, more preferably 1% - 5%, for example, 4%; (c) The borosilicate glass further includes zirconium; among them, preferably, the mass percentage of zirconium in the borosilicate glass is 1% - 5%, for example, 1.9% or 4%; (d) The borosilicate glass further includes molybdenum; among them, preferably, the mass percentage of molybdenum in the borosilicate glass is 1% - 5%, for example, 1.5% or 4%; (e) The borosilicate glass further includes rare earth elements, and the rare earth elements include one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; among them, preferably, the mass percentage of the rare earth elements in the borosilicate glass is 1% - 10%, for example, 2%.

4. The method for dissolving precious metals according to claim 1, characterized in that, It satisfies one or more of the following conditions: (a) In step S1, the concentration of the hydrofluoric acid solution is 30% - 50%, for example, 40%; among them, preferably, the solvent of the hydrofluoric acid solution is water; (b) In step S1, the mass ratio of aqua regia to the borosilicate glass is 8:1 or more. In step S1, the mass ratio of the hydrofluoric acid solution to the borosilicate glass is 1:1 or more.

5. The method for dissolving precious metals according to claim 1, characterized in that, It satisfies one or more of the following conditions: In step S1, the temperature in the heat preservation stage of the first heating is 100 - 150 °C; In step S1, the heating rate in the heating-up stage of the first heating is 1 - 3 °C / min; In step S1, the time in the heat preservation stage of the first heating is 3 - 6 h, for example, 4 h; In step S1, the D50 particle size of the borosilicate glass is 75 μm or less.

6. The method for dissolving precious metals according to claim 1, characterized in that, It satisfies one or more of the following conditions: In step S2, the mass ratio of the bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example, 7.8:1, 8.4:1 or 12:1; In step S2, the bisulfate is sodium bisulfate and / or potassium bisulfate; Among them, preferably, the mass ratio of the sodium bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example, 7.8:1, 8.4:1 or 12:1; Among them, preferably, the mass ratio of rhodium element in the sodium bisulfate to the borosilicate glass is 77:1 or more, more preferably 150:1 or more, still more preferably 162:1 or more, preferably 200:1 or more, for example, 231:1, 2400:1 or 40000:1; Among them, preferably, the mass ratio of palladium element in the sodium bisulfate to the borosilicate glass is 19:1 or more, more preferably 37:1, still more preferably 40:1, preferably 50:1 or more, for example, 57:1, 95:1, 2400:1 or 40000:1; Among them, preferably, the mass ratio of the potassium bisulfate to the borosilicate glass is 4:1 or more, more preferably 6:1 or more, still more preferably (6 - 20):1, preferably (6 - 16):1, for example, 7.8:1, 8.4:1 or 12:1; Among them, preferably, the mass ratio of rhodium element in the potassium bisulfate to the borosilicate glass is 200:1 or more; Among them, preferably, the mass ratio of palladium element in the potassium bisulfate to the borosilicate glass is 50:1 or more.

7. The method for dissolving precious metals according to claim 1, characterized in that, It satisfies one or more of the following conditions: In step S2, the temperature in the heat preservation stage of the second heating is 600 - 650 °C; In step S2, the heating rate in the heating-up stage of the second heating is 1.5 - 2.5 °C / min, for example, 1.8 °C / min; In step S2, the time in the heat preservation stage of the second heating is 6 - 8 h.

8. The method for dissolving precious metals according to claim 1, characterized in that, It satisfies one or more of the following conditions: In step S3, the acid solution is one or more of hydrochloric acid, sulfuric acid and nitric acid; Among them, preferably, the mass concentration of the hydrochloric acid is 5% - 10%; Preferably, the mass concentration of the nitric acid is 5% - 10%; Preferably, the mass concentration of the sulfuric acid is 5% - 10%; (b) In step S3, the mass ratio of the acid solution to the second product is (15 - 50):1, preferably (15 - 30):1, such as 25:1 or 50:1; (c) In step S3, the temperature of the heat preservation stage of the third heating is 80 - 100 °C; (d) In step S3, the heating rate of the temperature rising stage of the third heating is 1 - 3 °C / min; (e) In step S3, the time of the heat preservation stage of the third heating is 1 - 2 h.

9. A quantitative analysis method for noble metals, characterized in that, It includes the following steps: testing and analyzing the third product obtained by using the dissolution method of the noble metal according to any one of claims 1 - 8.

10. The quantitative analysis method of precious metals according to claim 9, characterized in that, The testing is carried out by inductively coupled plasma emission spectrometry and / or inductively coupled plasma mass spectrometry; And / or, the quantitative analysis method of the noble metal further includes the step of preparing a standard series calibration solution; Among them, when the testing is carried out by inductively coupled plasma emission spectrometry, the concentration of each element in the standard series calibration solution is preferably 0 - 10 mg / L; Among them, when the testing is carried out by inductively coupled plasma mass spectrometry, the concentration of each element in the standard series calibration solution is preferably 0 - 100 μg / L.

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