Method for extracting platinum group metal from three-way catalyst

Abstract

The invention provides a method for extracting platinum group metal from a three-way catalyst. The method comprises the following steps: weighing 100 parts by weight of the three-way catalyst, 240-320 parts by weight of a trapping agent nickel matte, 15-25 parts by weight of a fluxing agent, 35-45 parts by weight of borax decahydrate and 5-15 parts by weight of a reducing agent, and uniformly mixing to obtain a mixture; the mixture is placed in the environment with the temperature ranging from 1400 DEG C to 1500 DEG C, nitrogen is introduced into the mixture, smelting is conducted for 120 min to 180 min, and then standing is conducted for 60 min to 90 min; and melting and layering the mixture to obtain smelting slag and PGMs alloy. The nickel in the high nickel matte can be chemically reacted with impurity metals such as copper, iron and the like, so that platinum, rhodium and palladium in the three-way catalyst are effectively enriched in the high nickel matte, and meanwhile, nitrogen is introduced into the melt to effectively stir the melt, so that the flowability of the melt can be improved, the separation efficiency of the palladium metal in the mixture is further improved, and the separation efficiency of the palladium metal in the mixture is further improved. And the recovery rates of platinum, rhodium and palladium metals can reach 99% or above after melting and layering.

Description

Technical Field

[0001] The invention relates to the technical field of precious metal smelting, and mainly to a method for extracting platinum group metals from a ternary catalyst. Background Art

[0002] Platinum group metals (PGMs) are widely used in the fields of automobiles, petroleum, electronics and electrical appliances, chemicals, aerospace, and environmental protection due to their excellent physical and chemical properties such as high stability, high temperature resistance, and good catalytic activity.

[0003] Waste three-way catalysts contain a large amount of precious metals such as platinum, palladium, and rhodium, and have a high recycling value. However, since these catalysts will gradually become ineffective or be replaced during use, a large amount of waste catalysts are discarded, which not only wastes precious resources, but also may cause secondary pollution to the environment.

[0004] With the development of the automobile industry, the number of discarded automobile exhaust purifiers will increase day by day, and the waste three-way catalyst has urgent recycling value, but the existing methods have problems such as complex process and the recovery rate still needs to be improved. Summary of the invention

[0005] In view of the problem that the recovery rate of platinum group metals in three-way catalysts in the prior art still needs to be improved, an object of the present invention is to provide a method for extracting platinum group metals from three-way catalysts.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for extracting platinum group metals from a three-way catalyst comprises the following steps:

[0008] Weigh 100 parts by weight of a three-way catalyst, 240-320 parts by weight of a collector, high-matte nickel, 15-25 parts by weight of a flux, 35-45 parts by weight of borax decahydrate, and 5-15 parts by weight of a reducing agent, and mix them evenly to obtain a mixture;

[0009] The mixture is placed in an environment with a temperature of 1400° C. to 1500° C., and nitrogen is introduced into the mixture for melting for 120 min to 180 min, and then allowed to stand for 60 min to 90 min;

[0010] The mixture is melted and layered to obtain smelting slag and PGMs alloy.

[0011] In one embodiment, the nickel content in the high nickel matte is 65% to 70%.

[0012] In one embodiment, the copper content in the high nickel matte is 2% to 5%.

[0013] In one embodiment, the iron content in the high nickel matte is 2% to 5%.

[0014] In one embodiment, the flux includes at least one of anhydrous sodium carbonate, calcium oxide, and calcium fluoride.

[0015] In one embodiment, the flow rate of the nitrogen is 0.1 m 3 / h~0.3m 3 / h.

[0016] In one embodiment, the reducing agent includes at least one of coal powder and carbon powder.

[0017] In one embodiment, the nickel matte is 280 parts by weight.

[0018] In one embodiment, in parts by weight, the flux is 20 parts, the borax decahydrate is 40 parts, and the reducing agent is 10 parts.

[0019] In one embodiment, the smelting time is 150 minutes.

[0020] In one embodiment, the standing time is 75 minutes.

[0021] In one embodiment, the mixture is placed in a bell-shaped crucible melting furnace for melting.

[0022] It can be seen from the above technical solution that the advantages and positive effects of the present invention are:

[0023] The present application discloses a method for extracting platinum group metals from a three-way catalyst, which uses high-matte nickel as a collector. High-matte nickel contains nickel, iron and copper, and can form alloys with platinum group metals such as platinum, rhodium and palladium under high temperature conditions. Among them, the nickel in high-matte nickel can increase the affinity of copper, iron and platinum group metals by chemically reacting with impurity metals such as copper and iron to form intermetallic compounds (such as nickel-copper alloy, nickel-iron alloy, etc.), so that the platinum, rhodium and palladium in the three-way catalyst are effectively enriched in high-matte nickel, thereby separating the platinum group metals from the complex catalyst system. Furthermore, the co-solvent and borax decahydrate can reduce the melting temperature of the mixture and increase the fluidity of the melt of the mixture in a molten state. At the same time, passing nitrogen into the melt can effectively stir the melt, thereby increasing the fluidity of the melt, further improving the separation efficiency of palladium metal in the mixture, and after melting and stratification, the recovery rate of platinum, rhodium and palladium metals can reach more than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a flow chart of the steps of a method for extracting platinum group metals from a three-way catalyst in one embodiment of the present application. DETAILED DESCRIPTION

[0025] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] As used herein, the term "prepared from" is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0027] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0028] In these examples, parts and percentages are by mass unless otherwise indicated.

[0029] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0030] It should be noted that according to the national standard test method for ceramic materials (QB / T 25782002) and the national standard test method for precious metal catalysts, the scrap automobile three-way catalyst includes the following key chemical components by weight percentage: Pd 0.131%, Pt 0.0712%, Rh 0.023%, Al 2 O 3 39.06%, SiO 2 31.66%, MgO4.60%, CaO 0.71%, CeO 2 1.742%, Ni 0.19%, S 0.56%, Pb 0.14%, Ag 0.021%, Fe 0.75%.

[0031] The above test results show that the content of platinum group metals in the scrap automobile three-way catalyst is relatively high (Pd has the highest content, exceeding 0.13%), and has extremely high recycling value. The main impurities are oxides of magnesium, aluminum and silicon, which are typical ceramic-based carrier catalysts. In addition, CeO in the catalyst 2 As an additive, it plays a role in improving the catalytic activity and dispersibility of platinum group metals. The remaining sulfur compounds, lead, etc. are presumably caused by the deposition of unburned gasoline decomposition products on the surface of the waste catalyst.

[0032] The present invention provides a method for extracting platinum group metals from a three-way catalyst, which is used for recovering platinum group metals in waste automobile three-way catalysts. The method has high recovery efficiency and low cost.

[0033] Figure 1 A flow chart showing the steps of a method for extracting platinum group metals from a three-way catalyst. Figure 1 , the method comprises the following steps:

[0034] S1: Weigh 100 parts by weight of a three-way catalyst, 240-320 parts by weight of a collector, high-matte nickel, 15-25 parts by weight of a flux, 35-45 parts by weight of borax decahydrate, and 5-15 parts by weight of a reducing agent, and mix them evenly to obtain a mixture.

[0035] It should be noted that high-grade nickel matte is a eutectic of nickel, copper, cobalt, iron and sulfur metal sulfides formed by primary smelting of nickel concentrate through electrolysis and conversion.

[0036] Among them, the nickel content in high nickel matte is 65% to 70%; the copper content in high nickel matte is 2% to 5%; and the iron content in high nickel matte is 2% to 5%.

[0037] Specifically, nickel matte is rich in metals such as nickel, iron and copper, which can have a strong chemical affinity with platinum group metals (platinum, rhodium, palladium) during the smelting process of scrap automobile three-way catalysts. Among them, nickel has reducing properties under high temperature conditions, which can extract platinum group metals from the three-way catalyst and enrich them in nickel matte. Nickel, iron, copper and other metals form alloy phases with platinum group metals, especially nickel can enhance its affinity for platinum group metals with copper, iron and other metals through intermetallic compounds (such as nickel-copper alloy and nickel-iron alloy).

[0038] That is to say, the nickel in the high-matte nickel forms an alloy with the platinum group metals, and through chemical reactions, the nickel can further promote the migration and enrichment of the platinum group metals (especially palladium, rhodium and platinum) to the alloy phase through the interaction with impurity metals such as copper and iron. The affinity between impurity metals such as copper and iron and platinum group metals is usually low, and the intervention of nickel can increase the affinity between these metals and platinum group metals, thereby enabling the platinum group metals to be separated from the complex three-way catalyst system during the smelting process. Compared with the prior art that mainly uses copper, iron, etc. as a collector, the present application uses high-matte nickel as a collector to achieve a higher recovery rate of platinum group metals.

[0039] The flux includes at least one of anhydrous sodium carbonate, calcium oxide and calcium fluoride.

[0040] In some specific embodiments, the flux may be calcium oxide. Calcium oxide can react with impurities such as silicon oxide in the melt to generate calcium silicate with a low melting point, thereby reducing the melting temperature and facilitating the smelting process. On the other hand, calcium oxide has higher chemical stability than other fluxes and reduces the cost of use.

[0041] The reducing agent includes at least one of coal powder and carbon powder. The reducing agent is used to react chemically with oxides in the raw materials, such as oxidized compounds of precious metals such as platinum, palladium, rhodium and other impurity oxides, to reduce the metal oxides to metal elements.

[0042] In some specific embodiments, the reducing agent may be coal powder, which has the advantages of low cost and good chemical reducibility in a high temperature environment during the extraction of palladium metal.

[0043] Specifically, pulverized coal can stably release reducing gases (such as CO) under high temperature conditions, thereby maintaining the continuity of the reducing environment in the melt, which is conducive to the complete reduction of platinum group metal oxides. In addition, when the carbon in the pulverized coal reacts with the metal oxides, it can quickly form metal elements, which is conducive to the enrichment of platinum, rhodium and palladium. At the same time, the heat released by the combustion of pulverized coal also helps to maintain a high temperature reaction environment.

[0044] Preferably, the flux is 20 parts, the borax decahydrate is 40 parts, the reducing agent is 10 parts, and the high nickel matte is 280 parts.

[0045] The above substances are mixed uniformly by grinding to obtain a mixture.

[0046] S2: placing the mixture in an environment with a temperature of 1400° C. to 1500° C., introducing nitrogen into the mixture for smelting for 120 min to 180 min, and then allowing the mixture to stand for 60 min to 90 min.

[0047] The mixture is placed in a bell-shaped crucible melting furnace for melting. The bell-shaped crucible melting furnace has good sealing properties, and a stable high-temperature environment can be formed in the furnace, thereby facilitating the uniform distribution of nitrogen in the reaction environment of the mixture. Moreover, nitrogen can be introduced into the melt by using the bell-shaped crucible melting furnace to form bubble disturbance in the bell-shaped furnace body, thereby promoting uniform distribution of melt components.

[0048] In the above smelting process, nitrogen is introduced into the melt to provide an inert atmosphere, and under the condition of nitrogen protection, the reducing atmosphere in the melt can be further maintained. In this way, when nitrogen is introduced, the platinum group metals can be effectively prevented from undergoing oxidation reaction with oxygen under high temperature environment, thereby maintaining their reduced state, thereby improving the recovery rate of precious metals. The introduction of nitrogen atmosphere can also protect high-grade nickel matte and its alloys from oxidation, ensuring the stability and high purity of the melt.

[0049] On the other hand, nitrogen can form bubble flow by passing it into the melt, which not only provides an inert atmosphere, but also stirs the melt. Stirring the melt can promote the full mixing of platinum group metals and high nickel matte, and accelerate the alloying process of platinum group metals, which can make it easier for platinum group metals to be captured in the high nickel matte alloy phase, further improving the separation efficiency of platinum group metals.

[0050] In some specific embodiments, the flow rate of nitrogen is 0.1m 3 / h~0.3m 3 / h. When the nitrogen flow rate is within this range, the viscosity of the melt is effectively reduced, the fluidity of the melt at high temperature is improved, and the effect of melt stratification is further improved. At the same time, excessive consumption of inert gas is avoided, thereby achieving dual savings in materials and energy.

[0051] Specifically, in the above-mentioned high-temperature smelting process, flux and borax decahydrate can lower the melting temperature, reduce the energy consumption required for smelting, and improve the fluidity of the melt. Moreover, borax decahydrate can improve the fluidity of the melt, which helps the platinum group metals to fully contact with high nickel matte, thereby improving the reaction efficiency. In the above-mentioned smelting process, flux and borax decahydrate can effectively improve the fluidity of the melt, thereby making it easier for the melt to be distributed throughout the reaction area, thereby improving the enrichment efficiency of the platinum group metals.

[0052] Preferably, in the above reaction process, the smelting time is 150 min.

[0053] Preferably, the standing time is 75 min.

[0054] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0055] Among them, after the smelting is completed, the melt is left to stand for a period of time, and the metals are naturally stratified due to density differences and chemical affinity. Specifically, PGMs alloys, that is, platinum group metal alloys (such as platinum-nickel alloys, palladium-nickel alloys, etc.) have a high density and will settle to the bottom of the melt, while the slag phase mainly composed of impurities such as oxides and silicates will float on the upper layer. In this way, after cooling and standing, the melt can separate the slag liquid on the upper layer by tilting the furnace body or using other methods, and collect the PGMs alloy on the lower layer to achieve high-purity platinum, rhodium, palladium and other metals. Recovery.

[0056] The present application discloses a method for extracting platinum group metals from a three-way catalyst, which uses high-matte nickel as a collector. High-matte nickel contains nickel, iron and copper, and can form alloys with platinum group metals such as platinum, rhodium and palladium under high temperature conditions. Among them, the nickel in high-matte nickel can increase the affinity of copper, iron and platinum group metals by chemical reactions with impurity metals such as copper and iron, and by forming intermetallic compounds (such as nickel-copper alloy, nickel-iron alloy, etc.), so that the platinum, rhodium and palladium in the three-way catalyst are effectively enriched in high-matte nickel, thereby separating the platinum group metals from the complex catalyst system. Furthermore, the cosolvent and borax decahydrate can reduce the melting temperature of the mixture and increase the fluidity of the melt of the mixture in a molten state. At the same time, passing nitrogen into the melt can effectively stir the melt, thereby increasing the fluidity of the melt and improving the separation efficiency of palladium metal in the mixture.

[0057] The method for extracting platinum group metals from a three-way catalyst of the present application can achieve capture rates of Pt, Pd, and Rh of 99.50%, 99.68%, and 100%.

[0058] Example 1

[0059] The method for extracting platinum group metals from a three-way catalyst in this embodiment comprises the following steps:

[0060] S1: Weigh 100 parts by weight of a three-way catalyst, 280 parts of a collector nickel matte, 20 parts of calcium oxide, 40 parts of borax decahydrate, and 15 parts of coal powder, and mix them evenly to obtain a mixture; wherein the nickel content in the nickel matte is 65%, the copper content is 2.5%, and the iron content is 2.5%.

[0061] S2: Place the mixture in a bell-shaped crucible melting furnace at 1450°C and introduce 0.2 m 3 / h nitrogen for smelting for 150 min and then let it stand for 75 min.

[0062] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0063] Example 2

[0064] S1: Weigh 100 parts by weight of a three-way catalyst, 240 parts of a collector nickel matte, 15 parts of calcium oxide, 35 parts of borax decahydrate, and 10 parts of coal powder, and mix them evenly to obtain a mixture; wherein the nickel content in the nickel matte is 65%, the copper content is 2%, and the iron content is 2%.

[0065] S2: Place the mixture in a bell-shaped crucible melting furnace at 1400°C and introduce 0.1 m 3 / h of nitrogen for 120 min, and then let it stand for 60 min.

[0066] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0067] Example 3

[0068] S1: Weigh 100 parts by weight of a three-way catalyst, 320 parts of a collector nickel matte, 25 parts of calcium oxide, 45 parts of borax decahydrate, and 15 parts of coal powder, and mix them evenly to obtain a mixture; wherein the nickel content in the nickel matte is 70%, the copper content is 5%, and the iron content is 5%.

[0069] S2: Place the mixture in a bell-shaped crucible melting furnace at 1450°C and introduce 0.3 m 3 / h nitrogen for 180 min, and then let it stand for 90 min.

[0070] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0071] Example 4

[0072] The method for extracting platinum group metals from a three-way catalyst in this embodiment comprises the following steps:

[0073] S1: Weigh 100 parts by weight of a three-way catalyst, 240 parts of a collector nickel matte, 15 parts of anhydrous sodium carbonate, 35 parts of borax decahydrate, and 10 parts of carbon powder, and mix them evenly to obtain a mixture; wherein the nickel content in the nickel matte is 65%, the copper content is 2%, and the iron content is 2%.

[0074] S2: Place the mixture in a bell-shaped crucible melting furnace at 1400°C and introduce 0.2 m 3 / h of nitrogen for 120 min, and then let it stand for 60 min.

[0075] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0076] Example 5

[0077] The method for extracting platinum group metals from a three-way catalyst in this embodiment comprises the following steps:

[0078] S1: Weigh 100 parts by weight of a three-way catalyst, 240 parts of a collector nickel matte, 15 parts of calcium fluoride, 35 parts of borax decahydrate, and 5 parts of carbon powder, and mix them evenly to obtain a mixture; wherein the nickel content in the nickel matte is 65%, the copper content is 2%, and the iron content is 2%.

[0079] S2: Place the mixture in a bell-shaped crucible melting furnace at 1400°C and introduce 0.1 m 3 / h of nitrogen for 120 min, and then let it stand for 60 min.

[0080] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0081] Comparative Example 1

[0082] S1: Weigh 100 parts by weight of a three-way catalyst, 280 parts of a collector copper, 20 parts of calcium oxide, 40 parts of borax decahydrate, and 15 parts of coal powder, and mix them evenly to obtain a mixture; wherein the nickel content in the high nickel matte is 65%, the copper content is 2.5%, and the iron content is 2.5%.

[0083] S2: Place the mixture in a bell-shaped crucible melting furnace at 1450°C and introduce 0.2 m 3 / h of nitrogen for 150 min and then allowed to stand for 75 min.

[0084] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0085] Comparative Example 2

[0086] S1: Weigh 100 parts by weight of a three-way catalyst, 280 parts of a collector iron, 20 parts of calcium oxide, 40 parts of borax decahydrate, and 15 parts of coal powder, and mix them evenly to obtain a mixture; wherein the nickel content in the high nickel matte is 65%, the copper content is 2.5%, and the iron content is 2.5%.

[0087] S2: Place the mixture in a bell-shaped crucible melting furnace at 1450°C and introduce 0.2 m 3 / h of nitrogen for 150 min and then allowed to stand for 75 min.

[0088] S3: After the mixture is melted and layered, smelting slag and PGMs alloy are obtained.

[0089] Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated respectively, and the evaluation method was as follows:

[0090] The raw materials, nickel-matte alloy phase and smelting slag were analyzed by TTR III X-ray diffractometer. The microscopic composition and element distribution of the alloy phase and smelting slag were analyzed and detected by JSM-6360LV scanning electron microscope (SEM) and EDX-GENESIS-60S X-ray energy spectrometer (EDS). The content of platinum group metals in the smelting slag samples was determined by fire assay, and the recovery rate was calculated based on the content of platinum group metals in the raw materials and slag. The data are shown in Table 1.

[0091] Table 1 Platinum group metal capture rate

[0092] Examples and Comparative Examples Pt capture efficiency Pd capture rate Rh capture rate Example 1 99.50％ 99.68％ 100％ Example 2 88.33％ 92.59％ 87.34％ Example 3 99.53％ 99.25％ 99.88％ Example 4 95.82％ 96.78％ 93.22％ Example 5 94.28％ 95.23％ 92.41％ Comparative Example 1 99.09％ 99.02％ 97.36％ Comparative Example 2 98.55％ 98.12％ 98.26％

[0093] It can be seen from Table 1 that the capture rate of the method in Example 1 is significantly better than that of Comparative Examples 1 and 2. Therefore, using high nickel matte as a collector can efficiently separate platinum group metals from a complex three-way catalyst system during the smelting process.

[0094] Through the above method detection and analysis, the capture rate of Pt can reach 99.50%, the capture rate of Pd can reach 99.68%, and the capture rate of Rh can reach 100%.

[0095] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A method for extracting platinum group metals from a three-way catalyst, characterized in that: The following steps are involved: Weigh 100 parts by weight of a three-way catalyst, 240-320 parts by weight of a collector, high-matte nickel, 15-25 parts by weight of a flux, 35-45 parts by weight of borax decahydrate, and 5-15 parts by weight of a reducing agent, and mix them evenly to obtain a mixture; The mixture is placed in an environment with a temperature of 1400° C. to 1500° C., and nitrogen is introduced into the mixture for melting for 120 min to 180 min, and then allowed to stand for 60 min to 90 min; The mixture is melted and layered to obtain smelting slag and PGMs alloy.

2. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The nickel content in the high nickel matte is 65% to 70%; The copper content in the high nickel matte is 2% to 5%; The iron content in the high nickel matte is 2% to 5%.

3. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The flux includes at least one of anhydrous sodium carbonate, calcium oxide and calcium fluoride.

4. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The nitrogen flow rate is 0.1m 3 / h~0.3m 3 / h.

5. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The reducing agent includes at least one of coal powder and carbon powder.

6. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: In parts by weight, the high nickel matte is 280 parts.

7. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: In parts by weight, the flux is 20 parts, the borax decahydrate is 40 parts, and the reducing agent is 10 parts.

8. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The smelting time is 150 min.

9. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The standing time is 75 min.

10. The method for extracting platinum group metals from a three-way catalyst according to claim 1, characterized in that: The mixture is placed in a bell-shaped crucible melting furnace for melting.

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