Method and system for detecting contents of platinum, palladium and rhodium in automobile exhaust purification catalyst and application

Abstract

The invention provides a method and system for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst and application, and relates to the technical field of automobile exhaust purification, the method comprises the following steps: crushing, grinding, sieving, performing microwave acidolysis, neutralizing, washing and drying a catalyst sample to obtain dry filter residues; a trapping agent and a fluxing agent are added into the dry filter residues, constant-temperature heating is conducted in inert gas, then cooling forming is conducted, and an alloy button is obtained; blowing ash on the alloy, then adding mixed acid into the alloy, heating the alloy in a water bath at 95 DEG C for 25-35 minutes to obtain a dissolved solution, then adding a masking agent into the dissolved solution, and oscillating to obtain a solution to be detected; and filtering the liquid to be detected, fixing the volume and detecting. According to the method, precise quantification of trace platinum, palladium and rhodium in the complex matrix catalyst can be realized, and the method has a relatively high recovery rate; meanwhile, pollution elements are prevented from being used, and the method is green and efficient and better conforms to the concept of green chemistry.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile exhaust purification technology, and in particular to a method and system for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst, and applications thereof. BACKGROUND

[0002] The automobile exhaust catalyst carrier mainly has two types of cordierite and metal, and the currently used catalyst is mostly a cordierite carrier coated with platinum group metals. Since the cordierite carrier is extremely stable and difficult to dissolve in acid and alkali, and the conversion of the Al2O3 crystal form in the high-temperature carrier of the exhaust gas leads to the formation of a package of platinum group metals, which makes it difficult to separate and enrich, thereby bringing great difficulty to the direct detection of platinum group metals in the waste automobile exhaust catalyst.

[0003] The current traditional detection method has significant limitations: although the fire assaying method can enrich noble metals, the recovery rate of rhodium is low, and the lead pollution is serious; the wet acid dissolution treatment is easy to cause incomplete dissolution due to the corrosion resistance of the catalyst carrier (such as alumina and cordierite), which affects the detection accuracy. In addition, the coexisting metal interference, complicated process and other problems further restrict the detection efficiency.

[0004] In view of the above defects, it is urgent to develop a detection method with high recovery rate, low pollution and wide applicability to realize accurate quantification of trace platinum, palladium and rhodium in complex matrix catalyst and provide a reliable analysis means for the industry.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] To solve the above technical problems, the first purpose of the present application is to provide a method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst, which can realize accurate quantification of trace platinum, palladium and rhodium in complex matrix catalyst and has a high recovery rate; at the same time, the use of pollution elements is avoided, which is green and efficient and more in line with the concept of green chemistry.

[0007] The second purpose of the present application is to provide a detection system for the content of platinum, palladium and rhodium in the above-mentioned automobile exhaust purification catalyst, which is matched with the detection method and can realize accurate quantification of complex matrix, further realizing intelligent detection.

[0008] The third purpose of the present application is to provide an application of the above-mentioned method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst in detecting the content of platinum, palladium and rhodium in a catalyst.

[0009] In order to achieve the purpose of the present application, the present application provides a method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst, comprising the following steps: S1, crushing, grinding, sieving the catalyst sample through a 200 mesh sieve, microwave acidolysis, neutralizing and washing with 3wt%-7wt% H3BO3 to pH=7.0, and then drying at 100℃-120℃ for 2h-3h to obtain dry residue; S2, adding a trapping agent and a fluxing agent to the dry residue, heating to 890℃-910℃ under inert gas, heating for 25min-35min, and then water quenching at 300℃ for 2s-5s to form an alloy buckle; S3, cupellation of the alloy buckle, then adding mixed acid to it, heating in a 95℃ water bath for 25min-35min to obtain a dissolution solution, and then adding a masking agent to the dissolution solution to obtain a test solution; S4, filtering, constant volume, and detection of the test solution; The trapping agent is a ternary alloy trapping agent of bismuth, tin, and copper. The trapping agent is prepared by mixing bismuth, tin, and copper in a mass ratio of (50-70):(20-30):(10-20).

[0010] Further, in the S2 step, the temperature of constant temperature heating under inert gas is 900℃, and the heating time is 30min; the flow rate of the inert gas is 2L / min.

[0011] Further, in the S3 step, the cupellation temperature is 950±5℃, and the cupellation time is 30min-40min.

[0012] Further, in the S3 step, the cupellation temperature is 950℃, and the cupellation time is 35min.

[0013] Further, the fluxing agent is prepared by mixing sodium tetraborate and silicon dioxide in a mass ratio of (1-3):1.

[0014] Further, the trapping agent is prepared by mixing bismuth, tin, and copper in a mass ratio of 65:25:15. The fluxing agent is prepared by mixing sodium tetraborate and silicon dioxide in a mass ratio of 2:1.

[0015] Further, the mixed acid is prepared by mixing mixed solution 1 and mixed solution 2 in a volume ratio of 30:1. The mixed solution 1 is prepared by mixing 37wt% HCl and 65wt% nitric acid in a volume ratio of 3:1. The mixed solution 2 is 0.5wt% HF.

[0016] Further, the masking agent is a 1wt% thiourea solution.

[0017] Further, the acid in the microwave acidolysis is 40wt%HF and 65wt%HNO3 mixed according to the volume ratio of 1:3; Further, the reagent used in the step of neutralization and washing is 5wt%H3BO3.

[0018] Further, drying is carried out at 110℃ for 2h.

[0019] Further, the mass ratio of dry filter residue and trapping agent is 1:10.

[0020] The application also provides a system for detecting the content of platinum, palladium and rhodium in a tail gas purification catalyst, comprising: a sample pretreatment module, which is connected with a microwave acidolysis module, a solid-liquid separation and filter residue treatment module, a smelting enrichment module, a cupellation module, a dissolution and constant volume module and an ICP-AES detection module in sequence.

[0021] The application also provides an application of the method for detecting the content of platinum, palladium and rhodium in a tail gas purification catalyst in detecting the content of platinum, palladium and rhodium in a catalyst.

[0022] The application has the following technical effects: The application realizes efficient extraction of platinum, palladium and rhodium in a catalyst by combining microwave acidolysis with ternary bismuth tin copper trapping agent smelting enrichment, so that the recovery rate of rhodium is increased to more than 95%; the cupellation-mixed acid dissolution process eliminates the interference of carriers, and the lower limit of detection is 0.1ug / g; the masking agent and the optimized acid system synergistically inhibit the interference of coexisting ions, and the relative standard deviation is less than 3%. The whole process is free of lead pollution, the detection period is shortened by 30%, is suitable for complex catalyst systems such as alumina / cordierite-based catalyst systems; at the same time, the steps of detection are significantly simplified, and the detection temperature is reduced, which provides a precise, green and efficient solution for precious metal resource recovery and product quality control. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0024] In a first aspect, a method for detecting the content of platinum, palladium and rhodium in a tail gas purification catalyst of an automobile, which can realize accurate quantification of trace platinum, palladium and rhodium in a complex matrix catalyst, has a high recovery rate, avoids the use of polluting elements, is green and efficient, and is more in line with the concept of green chemistry.

[0025] The method comprises the following steps: S1, crushing, grinding, sieving the catalyst sample through a 200-mesh sieve, microwave acidolysis, neutralizing and washing with H3BO3 of 3wt%-7wt% to pH=7.0, and then drying at 100-120 DEG C for 2-3h to obtain dry residue; S2, adding a collector and a fluxing agent to the dry residue, heating to 890-910 DEG C under inert gas, heating for 25-35min, and then water quenching at 300 DEG C for 2-5s to form an alloy button; S3, cupellation of the alloy button, then adding mixed acid to the alloy button, heating in a 95 DEG C water bath for 25-35min to obtain a dissolution solution, and then adding a masking agent to the dissolution solution to obtain a test solution; S4, filtering, constant volume and detection of the test solution; The collector is a bismuth, tin and copper ternary alloy collector. The collector is prepared by mixing bismuth, tin and copper in a mass ratio of (50-70):(20-30):(10-20).

[0026] The application uses microwave acidolysis, and microwave energy can effectively accelerate the destruction of mixed acid to the cordierite or Al2O3 carrier structure, completely break the cordierite package, eliminate the carrier interference, and release the platinum group elements. At the same time, the bismuth, tin and copper ternary alloy collector is used, and the alloy of the three elements can efficiently collect platinum, palladium and rhodium in a molten state, form an alloy phase that is easy to separate, and the collection efficiency of the ternary alloy to rhodium is >95%, which can effectively solve the problem of low rhodium recovery rate in the traditional fire assay method, and further improve the recovery rate. At the same time, bismuth is used to replace lead, which greatly reduces lead pollution. The fluxing agent reduces the melting point and promotes phase separation. Inert gas prevents oxidation loss. High-temperature cupellation can remove base metals in the alloy button and enrich noble metals. The addition of mixed acid can completely dissolve the noble metal enrichment phase and break the package of residual oxides. Finally, the addition of a masking agent can complex Cu 2+ and other interfering ions to avoid detection interference.

[0027] The ratio of the collector is optimized. Bismuth, as the main collector, has a relatively low melting point, which can significantly reduce the melting point of the entire alloy system, improve the fluidity in the molten state, and enable the collector to fully contact with the sample melt, efficiently "hunt" and capture dispersed platinum group metal (PGMs) particles. The noble metal alloy button formed after melting has a large density and is easy to separate from the slag phase (molten slag) with a smaller density, thereby improving the recovery rate. Bismuth has similar chemical properties to lead and can meet the basic requirements of a collector, but it is non-toxic and environmentally friendly, achieving the goal of "green chemistry" and avoiding the harm of lead to the environment and operating personnel.

[0028] Tin modulates the melting point, further enhancing the alloy's fluidity and strengthening its affinity for rhodium. Rhodium readily forms stable intermetallic compounds with tin (such as RhSn2). In its molten state, tin effectively "pulls" rhodium into the alloy phase, significantly resolving the problem of low rhodium recovery (typically <85%) in traditional lead assaying.

[0029] Copper improves the alloy's mechanical strength. Bismuth and tin alloy buckles are typically soft and brittle. The addition of copper (melting point 1083°C) creates a more robust metal network structure, making the resulting alloy buckle mechanically strong and resistant to breakage, facilitating subsequent ash blowing and forming. Copper also optimizes the surface tension of the molten alloy, enhancing its wettability and capture efficiency for PGMs. Copper also has a certain capture capacity for platinum and palladium, creating a synergistic effect with Bi and Sn. By optimizing the ratio of these three metals, the surface tension of the molten state is increased, thereby enhancing the capture capacity and efficiency of precious metals.

[0030] In the present invention, the contents of the three metals are simultaneously limited to ensure that bismuth is within this range, ensuring that the alloy remains bismuth-based and maintaining a low eutectic melting point (the melting point of the Bi-Sn-Cu ternary alloy can be below 300°C), resulting in excellent fluidity at a heating temperature of 900°C. Furthermore, the high bismuth content ensures that the alloy has sufficient density for separation from the slag. When the bismuth content is too high, the alloy becomes too soft, lacks mechanical strength, and is prone to collapse during ash blowing. The effective ingredients in the total amount of the collector are relatively reduced, which may affect the capture efficiency of Rh. When the bismuth content is too low, the alloy melting point increases, the fluidity deteriorates, and the capture effect decreases. The reduced density may lead to incomplete slag-metal separation.

[0031] The amount of tin used optimizes rhodium capture. This ratio provides sufficient tin to fully react with trace amounts of rhodium to form a stable compound, which is key to achieving rhodium recoveries exceeding 95%. Furthermore, this ratio forms a good eutectic with Bi and Cu without significantly increasing the alloy's melting point. Excessive tin increases the alloy's tendency to oxidize, potentially forming more tin oxides during ash blowing. These oxides can encapsulate PGMs and cause losses. It can also make the alloy brittle. Insufficient tin content prevents the effective capture of all rhodium, resulting in reduced rhodium recovery and a failure to address the core issue.

[0032] The copper dosage is set to achieve optimal mechanical properties. This ratio is sufficient to form a strong mesh structure, significantly improving the hardness and flatness of the alloy buckle, enabling it to withstand the physical stress of subsequent high-temperature ash blowing without breaking. At the same time, this proportion of copper has the least negative impact on the melting point and fluidity; when its dosage is too large, it will significantly increase the overall melting point of the alloy, which may lead to poor fluidity at the set temperature and affect the capture efficiency. Excessive copper will also introduce more Cu after dissolution.2+ The ions increase the burden of the masking agent and potential interference. When the amount is insufficient, the alloy is not strong enough, easy to break, and prone to breakage during transfer and cupellation, resulting in physical loss of PGMs.

[0033] In the present application, the three metals work together in a clear division of labor, achieving the effect of 1+1+1>3. Not only can it significantly simplify the detection steps and reduce the reaction temperature, but also effectively improve the detection accuracy.

[0034] In some embodiments, in the S2 step, the temperature of constant temperature heating under inert gas is 900±10℃, and the heating time is 25-30 min; the flow rate of the inert gas is 2 L / min.

[0035] In the S2 step, the heating conditions are controlled to ensure the fluidity of the alloy, so that the ternary alloy is completely melted and efficiently captures platinum, palladium and rhodium; at the same time, by controlling the flow rate of the inert gas, the oxidation prevention and the volatilization of noble metals are balanced, the stability of the reaction is ensured, the platinum, palladium and rhodium are fully captured, the capture effect is ensured, and the loss of noble metals is avoided.

[0036] In some embodiments, in the S3 step, the temperature of cupellation is 950±5℃, and the cupellation time is 30-40 min.

[0037] Under the condition of about 950℃, the base metal can be oxidized and the noble metal is retained. The base metal residue caused by insufficient time or the noble metal loss caused by too long time is prevented, the enrichment purity is improved, and the subsequent acid consumption and interference are reduced.

[0038] In some embodiments, the capture agent is bismuth, tin and copper mixed in a mass ratio of (50-70):(20-30):(10-20). The fluxing agent is sodium tetraborate and silicon dioxide mixed in a mass ratio of (1-3):1.

[0039] In some embodiments, the capture agent is bismuth, tin and copper mixed in a mass ratio of 65:25:15. The fluxing agent is sodium tetraborate and silicon dioxide mixed in a mass ratio of 2:1.

[0040] Sodium tetraborate and silicon dioxide are mixed in a mass ratio of 2:1 to form a eutectic, which promotes slag-metal separation.

[0041] In some embodiments, the mixed acid is mixed by mixing liquid 1 and mixing liquid 2 in a volume ratio of 30:1. The mixing liquid 1 is 37wt% HCl mixed with 65wt% nitric acid in a volume ratio of 3:1. The mixing liquid 2 is 0.5wt% HF.

[0042] The mixed acid is mixed from aqua regia and low concentration hydrofluoric acid. On one hand, aqua regia can dissolve platinum, palladium and rhodium, and the hydrofluoric acid can further clean the SiO2 or cordierite residue after cupellation; and the low concentration hydrofluoric acid can reduce the corrosion of the equipment, while avoiding excessive fluorine interference in detection.

[0043] In some embodiments, the masking agent is a 1wt% thiourea solution.

[0044] Thiourea and Cu 2+ Forming stable complex [Cu(SCN2H4)4] 2+ Eliminating the spectral line interference of Cu on ICP-AES detection, thereby improving the accuracy of platinum, palladium and rhodium detection.

[0045] In some embodiments, the acid in the microwave acidolysis is 40wt% HF and 65wt% HNO3 mixed according to a volume ratio of 1:3; The reagent used in the neutralization and washing step is 5wt% H3BO3.

[0046] Hydrofluoric acid can destroy silicate carriers, nitric acid can oxidize organic matter; boric acid can generate stable fluoroborate, neutralize residual HF and prevent equipment corrosion.

[0047] In some embodiments, the drying step in the S1 step is specifically: drying at 110-120℃ for 2-3h; Further, drying at 110℃ for 2h.

[0048] In some embodiments, the specific step of cooling and forming in the S2 step is: pouring the melt into a preheated 300℃ mold and water quenching, 1s≤water quenching time≤5s.

[0049] The following will be described in conjunction with specific embodiments: Example 1 A. Microwave acidolysis pretreatment Crushing to 200 mesh by a vibrating sample machine, taking 10g of sample, mixing HF(40wt%) : HNO3(65wt%) = 1:3, keeping the total acid volume at 50mL; then filtering to obtain filter residue, and then using 5wt% H3BO3 solution 200mL to wash the filter residue, so that the pH of the filter residue is 7.0.

[0050] Then put the filter residue into an oven and dry at 110℃ for 2h to obtain dry filter residue.

[0051] B. Ternary alloy smelting enrichment Preparing ternary alloy: mixing bismuth powder: tin powder: copper powder according to a mass ratio of 6g:2.5g:1.5g; Simultaneous fluxing agent: sodium tetraborate and silica were mixed with mass ratio of 3g: 1.5g.

[0052] The magnesia crucible was preheated to 900℃, 1g dry residue was taken, and the ternary alloy and fluxing agent were loaded into the magnesia crucible, and argon was passed at a flow rate of 2L / min for constant temperature heating for 30min, until the material was in a molten state; then the melt was poured into a mold preheated to 300℃, and then water quenched for 5s to obtain an alloy button.

[0053] C. Combined treatment of cupellation-dissolution Prepare mixed acid: HCl (37wt%): HNO3 (65wt%) volume ratio = 3: 1, prepare 30mL, prepare aqua regia; add 0.5wt% HF 1mL to the aqua regia.

[0054] Cupellation the alloy button at 950℃ for 35min, then heat with mixed acid in a 95℃ water bath for 30min to obtain a dissolution solution; then add 1wt% thiourea solution 10mL to the dissolution solution and shake for 5min.

[0055] Then filter using a 0.22μm glass fiber membrane, then make up to 50mL, then perform ICP-AES detection.

[0056] Example 2 The specific implementation is consistent with Example 1, mix bismuth powder: tin powder: copper powder according to mass ratio = 7g: 2g: 1g.

[0057] Example 3 The specific implementation is consistent with Example 1, mix bismuth powder: tin powder: copper powder according to mass ratio = 5g: 3g: 2g.

[0058] Example 4 The specific implementation is consistent with Example 1, mix sodium tetraborate and silica with mass ratio = 1.5g: 1.5g.

[0059] Example 5 The specific implementation is consistent with Example 1, mix sodium tetraborate and silica with mass ratio = 4.5g: 1.5g.

[0060] Comparative Example 1: Traditional lead button method Take 10g of catalyst powder and mix with 150g of flux (PbO: Na2CO3: borax = 2: 1: 0.5), add 15g of silver foil as a protective agent, and load into a magnesia crucible; Melt at 980℃ for 40min to form a lead alloy button; The lead button was put into a cupel at 950℃, and the lead oxide was absorbed by the cupel. The silver button containing PGMs was left; The silver button was dissolved in 10mL hot nitric acid, and the solution was diluted to 50mL after filtration. The PGMs content in the solution was analyzed.

[0061] Comparative Example 2: Copper-nickel button fire assay method The sample was roasted at 650℃ for 2 hours to remove sulfur; The sample was mixed with 30g nickel sulfide, 20g copper sulfide and 10g sodium carbonate, and then smelted at 1150℃ for 1 hour to form a copper-nickel button; The button was crushed, and the base metals were leached with 10wt% sulfuric acid. The PGMs-rich residue was left; The residue was dissolved in 40mL aqua regia (HCl:HNO3=3:1) at 95℃ for 1 hour; The solution was enriched in PGMs by passing through an activated carbon column, and then diluted to volume after ashing; The content of PGMs was determined by atomic absorption spectrometry.

[0062] Comparative Example 3: Tin capture-cupellation method 10g sample was mixed with 200g tin button and 20g borax, and then smelted at 900℃ for 30min; The tin button was put into a cupellation furnace, and the temperature was raised to 1000℃ at a rate of 20℃ / min, and then kept constant until the tin was completely oxidized and volatilized; The PGMs-rich residue was dissolved in 30mL aqua regia (HCl:HNO3=3:1) at 30℃; 5mL hydrobromic acid was added to remove antimony-tin oxide precipitate; The filtrate was diluted to 25mL, and then analyzed by ICP-AES.

[0063] Experimental Example 1: Recovery rate comparison Standard sample preparation: cordierite carrier was loaded with known amounts of platinum, palladium and rhodium (50μg / g each); The standard sample was treated using the detection methods of the examples and comparative examples, and the PGMs content was detected by ICP-AES.

[0064] Calculation of recovery rate: recovery rate = detected value / nominal value x 100%.

[0065] The experimental results are shown in Table 1.

[0066] Table 1: Recovery rate of platinum, palladium and rhodium in examples and comparative examples

[0067] Experimental Example 2: Precision and residual contamination element verification Take the same sample (Pt / Pd / Rh = 50 / 30 / 10 μg / g), respectively, using the above detection method parallel processing 6 times, the relative standard deviation (RSD) of 6 detection results are calculated, RSD < 3%.

[0068] At the same time, the residual of the pollution elements after the detection of the examples and the comparative examples is detected, and the experimental results are shown in Table 2.

[0069] Table 2: Precision and pollution element residue of examples and comparative examples

[0070] In the present application, the detection limit of example 1 can reach 0.1 μg / g, which can be seen that the detection method of the present application has high sensitivity, which can provide accurate data basis for precious metal resource recovery.

[0071] From the comparison of the above examples 1 and comparative examples 1-3, it can be seen that the detection method of the present application can not only realize the efficient recovery of platinum, palladium and rhodium; at the same time, the detection method has high precision, which effectively improves the accuracy of detection; in addition, it can effectively reduce the residual of pollution elements, and provide accurate, green and efficient solution for precious metal resource recovery and product quality control.

[0072] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting the content of platinum, palladium and rhodium in automobile exhaust purification catalysts, characterized in that: The steps include: S1. The catalyst sample was crushed, ground, passed through a 200-mesh sieve, subjected to microwave acid hydrolysis, neutralized and washed with 3-7 wt% H3BO3 to a pH of 7.0, and then dried at 100-120°C for 2-3 hours to obtain a dry residue; S2. Add a collector and a flux to the dry filter residue, heat to 890° C.-910° C. under an inert gas constant temperature, heat for 25 min-35 min, and then water quench at 300° C. for 2 s-5 s to form an alloy buckle; S3. Blow the alloy button ash, then add mixed acid thereto, heat in a water bath at 95°C for 25-35 minutes to obtain a solution, then add a masking agent to the solution and shake it to obtain a test solution; S4, filtering, fixing and testing the liquid to be tested; Wherein, the collector is a ternary alloy collector of bismuth, tin and copper; The collector is prepared by mixing bismuth, tin and copper in a mass ratio of (50-70): (20-30): (10-20).

2. The method for detecting the content of platinum, palladium and rhodium in automobile exhaust purification catalyst according to claim 1, wherein: In the step S2, the temperature of the constant temperature heating under the inert gas is 900° C., and the heating time is 30 minutes; the flow rate of the inert gas is 2 L / min.

3. The method for detecting the content of platinum, palladium and rhodium in automobile exhaust purification catalyst according to claim 1, wherein: In the step S3, the temperature of the ash blowing is 950±5° C., and the time of the ash blowing is 30 min-40 min.

4. The method for detecting the content of platinum, palladium and rhodium in automobile exhaust purification catalyst according to claim 1, wherein: The flux is prepared by mixing sodium tetraborate and silicon dioxide in a mass ratio of (1-3):

1.

5. The method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst according to any one of claims 1 or 4, wherein: The collector is prepared by mixing bismuth, tin and copper in a mass ratio of 65:25:15; The flux is prepared by mixing sodium tetraborate and silicon dioxide in a mass ratio of 2:

1.

6. The method for detecting the content of platinum, palladium and rhodium in a vehicle exhaust gas purification catalyst according to claim 1, characterized in that: The mixed acid is mixed with mixed solution 1 and mixed solution 2 at a volume ratio of 30:1; Wherein, mixed solution 1 is a mixture of 37 wt % HCl and 65 wt % nitric acid in a volume ratio of 3:1; Mixed solution 2 is 0.5 wt% HF.

7. The method for detecting the content of platinum, palladium and rhodium in a vehicle exhaust gas purification catalyst according to claim 1, wherein: The masking agent is 1 wt% thiourea solution.

8. The method for detecting the content of platinum, palladium and rhodium in a vehicle exhaust gas purification catalyst according to claim 1, characterized in that: The acid in the microwave acid hydrolysis is a mixture of 40 wt % HF and 65 wt % HNO 3 in a volume ratio of 1:3; The reagent used in the neutralization and washing step is 5 wt % H 3 BO 3 .

9. A system used in the method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst according to any one of claims 1 to 8, characterized in that: include: The sample pretreatment module is sequentially connected to the microwave acid hydrolysis module, the solid-liquid separation and residue treatment module, the smelting and enrichment module, the ash blowing module, the dissolution and constant volume module and the ICP-AES detection module.

10. Use of the method for detecting the content of platinum, palladium and rhodium in an automobile exhaust purification catalyst according to any one of claims 1 to 8 in detecting the content of platinum, palladium and rhodium in a catalyst.

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