A method for enriching platinum group metals in a failed automotive catalyst

Abstract

The present invention discloses a method for enriching platinum group metals in spent automotive catalysts. First, the spent automotive catalysts are crushed and finely ground to a particle size of less than 0.15 mm. After being uniformly mixed according to the mass ratio of spent automotive catalysts: collector: reducing agent: flux of 1:(0.10 - 0.20):(0.05 - 0.15):(0.6 - 0.8), they are reductively smelted at 1300 - 1550 °C. Then, the iron-tin alloy enriched with platinum group metals is atomized into powder or ball-milled, and added to a sulfuric acid solution for dissolution, with the liquid-solid ratio controlled at 2 - 6:1. After the leaching residue is sulfated and roasted, controlled-potential hydrochloric acid leaching is carried out with a hydrochloric acid solution. By adding hydrazine hydrate, the oxidation-reduction potential of the solution is controlled at -100 - 150 mV to achieve the efficient enrichment of platinum group metals. The smelting capture rate of platinum group metals in the present invention is greater than 99%, and the comprehensive recovery rate is greater than 98.5%.

Description

Technical Field

[0001] The present invention relates to the process of recycling secondary resources of platinum group metals, and is a method for efficiently capturing and deeply enriching platinum group metals in spent automotive catalysts. Technical Background

[0002] At present, automotive catalysts with cordierite (2MgO·2Al 2 O 3 ·5SiO 2 ) as the carrier dominate the market. Cordierite is an inert substance resistant to acids and alkalis, and wet process treatment of such catalysts does not have advantages. Compared with hydrometallurgical processes, the metal capture method in pyrometallurgical processes has the advantages of mature technology and high PGMs recovery rate, and has become an important way to recover platinum group metals in such catalysts. However, there are three key problems in traditional metal capture processes: firstly, such catalysts have a high cordierite content and a high melting temperature, so a relatively high smelting temperature (>1600 °C) is required; secondly, the traditional iron capture process requires a high temperature of 1600 - 2000 °C, with high energy consumption, and the reduction smelting at high temperature leads to the formation of a large amount of ferrosilicon alloy, making it difficult to separate platinum group metals from the alloy phase in the subsequent process; thirdly, the iron alloy phase obtained by smelting often contains impurities C, and directly leaching iron with acid does not achieve ideal leaching effects.

[0003] To reduce the smelting temperature, patents (application numbers: 202110861970.0, 202110978732.8, 202111066748.8) reduce the melting temperature to 1250 - 1450 °C by adding fluxes containing magnesium and manganese. Although this method realizes the efficient recovery of platinum group metals at a relatively low temperature, manganese has a strong affinity for oxygen, and in this process, manganese is easily oxidized and enters the slag phase, resulting in a large loss of metal capture agents and greatly increasing the production cost.

[0004] Copper has a relatively low melting point, and some researchers use copper to replace iron or cooperate with iron for capture. Patents (application numbers: 202211148638.0, 202110978883.3) respectively use copper and copper - antimony as capture agents, and both achieve the efficient capture of platinum group metals at low temperatures (1000 - 1200 °C). However, the obtained copper - containing alloys require multiple oxidation blowing or electrolytic refining in subsequent treatment, and there are problems such as large difficulty in separating copper from platinum group metals, long process flow, and high energy consumption. Patent (application number: 202111371066.8) discloses a method for co - disposing copper electroplating sludge (containing Cu, Fe) and spent automotive catalysts, which essentially uses copper and iron to cooperate in capturing platinum group metals in the catalyst. The reduction smelting temperature of this process is 1450 - 1600 °C, and there is still a problem of the formation of a large amount of ferrosilicon alloy (>1420 °C, ferrosilicon alloy can be formed).

[0005] Ding Yunji (Research on the Enrichment Mechanism and Application of Platinum Group Metals in Spent Catalysts [D]. University of Science and Technology Beijing, 2019.) and Dong Haigang et al. (Recovery of Platinum Group Metals from Secondary Resources by Solid-State Reduction Iron Trapping Method [J]. The Chinese Journal of Nonferrous Metals, 2014, 24(10): 2692-2697.) avoided the formation of ferrosilicon alloy by reducing the smelting temperature. However, the obtained iron-based alloy has high hardness, difficult to crush, and low acid leaching efficiency. Subsequently, they added aluminum to pulverize the iron-based alloy, and then dissolved Fe and Al with dilute acid to achieve the enrichment of platinum group metals. However, this method also has problems such as a large amount of aluminum powder consumption and the formation of Al(OH) 3 colloid affecting the filtration speed and other issues. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems of high temperature in traditional smelting for trapping platinum group metals, easy generation of ferrosilicon alloy, and difficulty in separating platinum group metals from alloys in the subsequent process, and to provide a method for enriching platinum group metals in spent automotive catalysts.

[0007] The technical solution adopted by the present invention to achieve the above purpose is: after finely grinding the spent automotive catalyst, it is mixed with a trapping agent, a reducing agent, and a flux, and then platinum group metals are enriched by iron-tin co-smelting; the obtained iron-tin alloy is dissolved with sulfuric acid, platinum, palladium, and rhodium enter the leaching residue, and most of the iron and tin are leached into the sulfuric acid leaching solution. This leaching solution is subjected to neutralization precipitation to obtain iron-tin precipitation slag I, which is directly returned to smelting; after the leaching residue is subjected to sulfation roasting and potential-controlled hydrochloric acid leaching, the iron and tin present in the leaching residue are further leached into the hydrochloric acid leaching solution. The hydrochloric acid leaching solution is subjected to neutralization precipitation to obtain iron-tin precipitation slag II, which is returned to smelting, while platinum, palladium, and rhodium are deeply enriched in the precious metal enrichment slag and sent to the platinum, palladium, and rhodium extraction process.

[0008] The specific process and technical parameters are as follows:

[0009] 1. Smelting Enrichment

[0010] The spent automotive catalyst is crushed and finely ground to a particle size of less than 0.15 mm, and then mixed evenly according to the mass ratio of spent automotive catalyst∶trapping agent (iron + tin)∶reducing agent∶flux (calcium oxide + sodium carbonate + borax) of 1∶(0.10-0.20)∶(0.05-0.15)∶(0.6-0.8). After that, it is placed in a graphite-clay crucible and subjected to reduction smelting at 1300-1550 °C for 2-5 h. Among them, the mass ratio of iron to tin in the trapping agent is 1∶0.8-1.2; the mass ratio of calcium oxide, sodium carbonate, and borax is 1∶(0.6-1)∶(0.1-0.3). After the smelting is completed, the slag phase and the metal phase are separated to obtain an iron-tin alloy preliminarily enriched with platinum group metals. The smelting slag generated in the smelting enrichment process can be used as building materials; the collected soot is returned to smelting.

[0011] 2. Sulfuric acid dissolution

[0012] Atomize the iron-tin alloy preliminarily enriched with platinum group metals by medium-frequency furnace or ball mill to a particle size of less than 0.15 mm, add it to a newly prepared sulfuric acid solution with a concentration of 2.0 - 6.0 mol / L for sulfuric acid dissolution, control the liquid-solid ratio (the ratio of liquid volume in mL to the mass of iron-tin alloy powder in g) to be 2 - 6:1, the sulfuric acid dissolution time to be 0.5 - 3 h, the dissolution temperature to be 50 - 95 °C, and the stirring speed to be 300 - 600 rpm. After the reaction, a sulfuric acid leaching solution and a leaching residue enriched with platinum group metals are produced. The produced sulfuric acid leaching solution is neutralized to pH 6 - 9 by adding sodium hydroxide, and an iron-tin precipitation slag I is produced and returned to the smelting enrichment process.

[0013] 3. Sulfation roasting

[0014] Roast the leaching residue and concentrated sulfuric acid according to the weight-volume ratio (the mass of leaching residue in g to the volume of concentrated sulfuric acid in mL) of 1:1 - 1.5 at 500 - 700 °C for 1 - 3 h to produce a roasted product.

[0015] 4. Controlled-potential hydrochloric acid leaching

[0016] Add the roasted product to a newly prepared hydrochloric acid solution with a concentration of 1.0 - 4.0 mol / L for controlled-potential hydrochloric acid leaching, control the ratio of hydrochloric acid solution in mL to the mass of roasted product in g to be 3 - 6:1, the leaching temperature to be 50 - 95 °C, the stirring speed to be 300 - 600 rpm. After leaching for 0.5 - 3 h, control the oxidation-reduction potential of the solution to be -100 - 150 mv by adding hydrazine hydrate; after stirring and reacting for 0.5 - 2 h, filter and wash to obtain a precious metal enriched slag and a hydrochloric acid leaching solution. Send the produced precious metal enriched slag to the platinum-palladium-rhodium separation and extraction process, and neutralize the produced hydrochloric acid leaching solution to pH 6 - 9 by adding sodium hydroxide to produce an iron-tin precipitation slag II and return it to the smelting enrichment process.

[0017] Furthermore, the collector is a combination of two or more of iron powder, tin powder or iron-tin precipitation slag, etc.; the mass ratio of iron to tin in the preferred collector is 1:0.8 - 1.0.

[0018] Furthermore, the fluxes calcium oxide, sodium carbonate, and borax are all industrial-grade reagents.

[0019] Furthermore, the reducing agent is any one or two of pulverized coal and coke powder.

[0020] Furthermore, the hydrochloric acid, sulfuric acid, hydrazine hydrate, and sodium hydroxide are industrial-grade reagents.

[0021] In the described spent automotive catalyst, the elemental mass percentages are as follows: Al 5.0% - 30.0%, Si 5.0% - 30.0%, Mg 5.0% - 15%, Ca 0.1% - 5%, Zr 1% - 5%, La 0.1% - 5.0%, Y 0.01% - 2.0%, Ce 1.0% - 15.0%, Pt 0 - 500.0 g / t, Pd 30.0 - 3000.0 g / t, and Rh 5.0 - 300.0 g / t.

[0022] (1) The smelting enrichment temperature of the present invention is 1300 - 1550 °C. By adjusting the material ratio of the smelting composition, the formation of ferrosilicon alloy is avoided, which is beneficial to the further enrichment of platinum group metals in the subsequent process. The iron-tin synergistic smelting is used to enrich the platinum group metals in the spent catalyst, strengthening the trapping effect of platinum group metals, and the trapping rate of platinum group metals is as high as over 99%. In addition, the clarification and separation of the slag phase and the metal phase are fast, and the energy consumption is low.

[0023] (2) For the iron-tin alloy obtained in the smelting enrichment process, the present invention adopts the process of sulfuric acid dissolution - sulfation roasting - controlled potential hydrochloric acid leaching for treatment, which has the characteristics of high enrichment rate of platinum, palladium, and rhodium. Compared with the content of platinum group metals in the raw material, the platinum, palladium, and rhodium in the precious metal enriched slag produced by the present invention are enriched by more than 240 times, and the content of platinum, palladium, and rhodium in the precious metal enriched slag is as high as 25 - 50%, which is beneficial to reducing the scale of subsequent separation and purification of platinum, palladium, and rhodium and lowering the labor intensity. In addition, through the above leaching process, the entry of platinum group metals into the solution can be inhibited, so that the comprehensive recovery rate of platinum group metals in the present invention is greater than 98.5%.

[0024] (3) The soot and iron-tin precipitation slag produced in the present invention can be returned to the smelting; the smelting slag produced belongs to general solid waste and can be directly used as building materials. The present invention realizes the efficient and deep enrichment of platinum group metals, significantly reducing the production cost. Description of the Drawings

[0025] Figure 1 : Process flow chart of the present invention. Detailed Embodiments

[0026] The present invention will be further described in detail below in conjunction with embodiments. It is worth noting that the implementation modes of the present invention are not limited to the scope represented by the embodiments.

[0027] Example 1

[0028] The main components of a certain spent automotive catalyst are as follows:

[0029] Al 17.97%, Si 17.78%, Mg 6.68%, Ca 0.33%, Zr 1.91%, La 0.58%, Y 0.28%, Ce 4.02%, Pt 116.5 g / t, Pd 217.6 g / t, Rh 80.0 g / t.

[0030] Industrial-grade iron powder, with its Fe content ≥ 99%; industrial-grade tin powder, with its Sn content ≥ 99%; industrial-grade calcium oxide, with its CaO content ≥ 98%; industrial-grade sodium carbonate, with its Na 2 CO 3 content ≥ 99%; industrial-grade borax, with its Na 2 B 4 O 7 ·10H 2 O content ≥ 95%; industrial-grade pulverized coal, with its fixed C content ≥ 70%; industrial-grade sulfuric acid, with its H 2 SO 4 mass fraction ≥ 98%; industrial-grade sodium hydroxide, with its NaOH content ≥ 96%; industrial-grade hydrochloric acid, with its HCl content 36% - 38%; industrial-grade hydrazine hydrate, with its water content 80%.

[0031] The process flow chart of the present invention is as Figure 1 shown. Take 1000.00 g of spent automotive catalysts with a particle size less than 0.15 mm after fine grinding and put them into a graphite-clay crucible. Add 75.0 g of iron powder, 75.0 g of tin powder, 350.00 g of calcium oxide, 350.00 g of sodium carbonate, 70.00 g of borax, and 50.00 g of carbon powder respectively. After mixing the above materials evenly, place them in a melting furnace preheated to 800°C, and then raise the temperature to 1450°C at a heating rate of 4°C / min and hold for 120 min. After the melting is completed, wait for the crucible to cool to room temperature with the furnace, take out the crucible, separate the slag phase and the alloy phase, and obtain 1492.42 g of melting slag and 147.30 g of iron-tin alloy. Conduct fire assay analysis on the slag phase. After detection, the capture rates of platinum, palladium, and rhodium are 99.10%, 99.40%, and 99.50% respectively. The contents of Pt, Pd, and Rh in the iron-tin alloy are 783.78 g / t, 1468.39 g / t, and 540.39 g / t respectively.

[0032] After crushing 147.30 g of iron-tin alloy to less than 0.15 mm, it was added to 450 ml of newly prepared 6 mol / L sulfuric acid solution for leaching. The acid leaching time was 1.5 h, the acid leaching temperature was 90 °C, and the stirring speed was 500 rpm. After the reaction was completed, the acid leaching residue was filtered, washed and dried. The filtrate and washing liquid were combined to obtain 462 ml of sulfuric acid leaching solution and 59.10 g of leaching residue. The composition of the sulfuric acid leaching solution was: Fe 74.70 g / L, Sn 119.28 g / L. The residue rate of the leaching residue was 40.12%, and the contents of Pt, Pd, and Rh were 0.20%, 0.37%, and 0.13% respectively. Take 462 ml of sulfuric acid leaching solution and add appropriate amount of sodium hydroxide to it until the solution pH is 6.5. Let it stand at room temperature for 60 min. After the precipitation is completed, the precipitate residue is filtered, washed and dried. The mass of the iron-tin precipitate residue I obtained was 130.12 g, which was returned to the smelting and enrichment process.

[0033] Take 59.10 g of sulfuric acid leaching residue and place it in a corundum crucible. Then add 60 mL of concentrated sulfuric acid dropwise and gently stir it with a glass rod to make it mix evenly. Place the crucible in a muffle furnace and heat it up with the furnace at a heating rate of 5 °C / min to 650 °C, and then roast for 2.5 h. After the roasting is completed, 92.87 g of roasted product is produced, and the roasting residue rate is 157.15%.

[0034] Add 92.87 g of the roasted product to 460 ml of newly prepared 4 mol / L hydrochloric acid solution for controlled-potential hydrochloric acid leaching. The acid leaching temperature was 90 °C, the stirring speed was 500 rpm. After acid leaching for 1.5 h, add hydrazine hydrate dropwise to control the redox potential of the solution to about 50 mV, and continue to react for 1.5 h. After the reaction is completed, the precious metal enrichment residue is filtered, washed and dried. The filtrate and washing liquid are combined to obtain 475 ml of hydrochloric acid leaching solution and 1.40 g of precious metal enrichment residue. The composition of the hydrochloric acid leaching solution was: Fe 87.11 g / L, Sn 28.34 g / L. The residue rate of the precious metal enrichment residue was 1.51%, and the total content of platinum group metals (Pt + Pd + Rh) in the precious metal enrichment residue was 29.33%. Among them, the contents of Pt, Pd, and Rh were 8.23%, 15.42%, and 5.68% respectively. The comprehensive residue rate in the whole process was 0.95%. Compared with the raw material of failed automotive catalysts, Pt, Pd, and Rh were enriched by 706.67, 708.81, and 709.53 times respectively. The precious metal enrichment residue was sent to the next step of platinum-palladium-rhodium separation and purification process. Take 475 ml of hydrochloric acid leaching solution and add appropriate amount of sodium hydroxide to it until the solution pH is 6.5. Let it stand at room temperature for 60 min. After the precipitation is completed, the precipitate residue is filtered, washed and dried. The mass of the iron-tin precipitate residue II obtained was 87.42 g, which was returned to the smelting and enrichment process.

[0035] Example 2

[0036] The main components of a certain failed automotive catalyst are as follows:

[0037] Al 18.24%, Si 16.55%, Mg 7.82%, Ca 0.78%, Zr 2.15%, La 0.64%, Y 0.34%, Ce 3.68%, Pd 1672.2 g / t, Rh 315.5 g / t.

[0038] Industrial-grade iron powder with Fe content ≥ 99%; industrial-grade tin powder with Sn content ≥ 99%; industrial-grade calcium oxide with CaO content ≥ 98%; industrial-grade sodium carbonate with Na 2 CO 3 content ≥ 99%; industrial-grade borax with Na 2 B 4 O 7 ·10H 2 O content ≥ 95%; coke powder with fixed C content ≥ 75%; industrial-grade sulfuric acid with H 2 5O 4 mass fraction ≥ 98%; industrial-grade sodium hydroxide with NaOH content ≥ 96%; industrial-grade hydrochloric acid with HCl content 36% - 38%; industrial-grade hydrazine hydrate with water content 80%.

[0039] Take 1200.00 g of the failed automotive catalyst with a particle size less than 0.15 mm after fine grinding and place it in a graphite-clay crucible. Add 122.0 g of iron powder, 98.0 g of tin powder, 409.00 g of calcium oxide, 327.00 g of sodium carbonate, 93.00 g of borax, and 90.00 g of carbon powder respectively. After mixing the above materials evenly, place them in a smelting furnace preheated to 800 °C, and then raise the temperature to 1530 °C at a heating rate of 5 °C / min and hold for 300 min. After the smelting is completed, wait for the crucible to cool to room temperature with the furnace, take out the crucible, separate the slag phase and the alloy phase, and obtain 1786.53 g of smelting slag and 218.06 g of iron-tin alloy. Conduct fire assay analysis on the slag phase, and after detection, the capture rates of palladium and rhodium are 99.37% and 99.55% respectively. In the iron-tin alloy, the contents of Pd and Rh are 0.91% and 0.17% respectively.

[0040] After crushing 218.06 g of iron-tin alloy to a particle size less than 0.15 mm, it was added to 880 ml of freshly prepared 5 mol / L sulfuric acid solution for leaching. The acid leaching time was 3.0 h, the acid leaching temperature was 75 °C, and the stirring speed was 600 rpm. After the reaction was completed, the acid leaching residue was filtered, washed, and dried. The filtrate and washing solution were combined to obtain 892 ml of sulfuric acid leaching solution and 91.89 g of leaching residue. The composition of the sulfuric acid leaching solution was: Fe 48.91 g / L, Sn 82.09 g / L. The residue rate of the leaching residue was 42.14%, and the contents of Pd and Rh were 2.17% and 0.41% respectively. Take 892 ml of sulfuric acid leaching solution and add an appropriate amount of sodium hydroxide to the solution until the pH is 6.5. Let it stand at room temperature for 60 min. After precipitation, the precipitate residue was filtered, washed, and dried to obtain 172.41 g of iron-tin precipitate residue one, which was returned to the smelting enrichment process.

[0041] Take 91.89 g of sulfuric acid leaching residue and place it in a corundum crucible. Then, add 120 mL of concentrated sulfuric acid dropwise and stir gently with a glass rod to make it mix evenly. Place the crucible in a muffle furnace and heat it up to 550 °C at a heating rate of 5 °C / min along with the furnace, and then roast for 3 h. After roasting, 150.90 g of roasted product was produced, and the roasting residue rate was 164.21%. Add 150.90 g of the roasted product to 610 ml of freshly prepared 2 mol / L hydrochloric acid solution for potential-controlled hydrochloric acid leaching. The acid leaching temperature was 75 °C, the stirring speed was 600 rpm. After acid leaching for 2 h, add hydrazine hydrate dropwise to control the oxidation-reduction potential of the solution to about 120 mv, and continue to react for 1 h. Then, filter, wash, and dry the noble metal enrichment residue. The filtrate and washing solution were combined to obtain 627 ml of hydrochloric acid leaching solution and 4.83 g of noble metal enrichment residue. The composition of the hydrochloric acid leaching solution was: Fe 106.64 g / L, Sn 22.34 g / L. The residue rate of the noble metal enrichment residue was 3.20%, and the total content of platinum group metals (Pd + Rh) in the noble metal enrichment residue was 49.10%, and the contents of Pd and Rh were 41.29% and 7.81% respectively. The comprehensive residue rate in the whole process was 2.21%. Compared with the raw material of failed automotive catalysts, Pd and Rh were enriched by 246.95 and 247.40 times respectively. The noble metal enrichment residue was sent to the next palladium-rhodium separation and purification process. Take 627 ml of hydrochloric acid leaching solution and add an appropriate amount of sodium hydroxide to the solution until the pH is 6.5. Let it stand at room temperature for 60 min. After precipitation, the precipitate residue was filtered, washed, and dried to obtain 136.51 g of iron-tin precipitate residue two, which was returned to the smelting enrichment process.

Claims

1. A method for enriching platinum group metals in spent automotive catalysts, characterized in that it includes the following steps: A: Smelting enrichment Crush the spent automotive catalyst and finely grind it to a particle size of less than 0.15 mm. After mixing evenly according to the mass ratio of spent automotive catalyst: collector: reducing agent: flux of 1∶(0.10 - 0.20)∶(0.05 - 0.15)∶(0.6 - 0.8), place it in a graphite-clay crucible and carry out reduction smelting at 1300 - 1550 °C for 2 - 5 h; among them, the collector is iron and tin, and the mass ratio of iron to tin is 1∶0.8 - 1.2; the flux is calcium oxide, sodium carbonate and borax, and the mass ratio is 1∶(0.6 - 1)∶(0.1 - 0.3); after the smelting is completed, separate the slag phase and the metal phase to obtain an iron-tin alloy preliminarily enriched with platinum group metals; the collected soot is returned to smelting; the capture rate of platinum group metals is greater than 99%; B: Sulfuric acid dissolution Atomize the iron-tin alloy preliminarily enriched with platinum group metals by medium-frequency furnace or ball mill to a particle size of less than 0.15 mm, add it to a newly prepared sulfuric acid solution with a concentration of 2.0 - 6.0 mol / L for sulfuric acid dissolution, control the ratio of liquid volume mL to the mass g of the iron-tin alloy powder as 2 - 6∶1, the sulfuric acid dissolution time is 0.5 - 3 h, the dissolution temperature is 50 - 95 °C, and the stirring speed is 300 - 600 rpm; after the reaction is completed, produce a sulfuric acid leaching solution and a leaching residue enriched with platinum group metals, add sodium hydroxide to the sulfuric acid leaching solution to adjust the pH to 6 - 9, produce an iron-tin precipitation slag one, and return it to the smelting enrichment process; C: Sulfation roasting Roast the leaching residue and concentrated sulfuric acid according to the weight-volume ratio of 1∶1 - 1.5 at 500 - 700 °C for 1 - 3 h to produce a roasted product; where the mass of the leaching residue is g and the volume of concentrated sulfuric acid is mL; D: Controlled-potential hydrochloric acid leaching Add the roasted product to a newly prepared hydrochloric acid solution with a concentration of 1.0 - 4.0 mol / L for controlled-potential hydrochloric acid leaching, control the ratio of hydrochloric acid solution mL to the mass g of the roasted product as 3 - 6∶1, the leaching temperature is 50 - 95 °C, the stirring speed is 300 - 600 rpm. After leaching for 0.5 - 3 h, control the oxidation-reduction potential of the solution at -100 - 150 mv by adding hydrazine hydrate; after stirring and reacting for 0.5 - 2 h, filter and wash to obtain a precious metal enrichment slag and a hydrochloric acid leaching solution. Send the produced precious metal enrichment slag to the platinum-palladium-rhodium separation and extraction process, and add sodium hydroxide to the produced hydrochloric acid leaching solution to neutralize it to a pH of 6 - 9 to produce an iron-tin precipitation slag two, and return it to the smelting enrichment process.

2. The method for enriching platinum group metals in spent automotive catalysts as described in claim 1, characterized in that: the mass ratio of iron to tin in the collector is 1∶0.8 - 1.

0.

3. The method for enriching platinum group metals in spent automotive catalysts as described in claim 1, characterized in that: the iron and tin in the collector, and the calcium oxide, sodium carbonate and borax in the flux are all industrial-grade reagents.

4. The method for enriching platinum group metals in spent automotive catalysts as described in claim 1, characterized in that: The reducing agent is any one or two of pulverized coal and coke powder.

5. The method for enriching platinum group metals in a spent automotive catalyst according to claim 1, characterized in that: the hydrochloric acid, sulfuric acid, hydrazine hydrate, and sodium hydroxide are industrial-grade reagents.

6. The method for enriching platinum group metals in a spent automotive catalyst according to any one of claims 1 to 5, characterized in that: in the spent automotive catalyst, the elemental mass percentages are: Al 5.0% - 30.0%, Si 5.0% - 30.0%, Mg 5.0% - 15%, Ca 0.1% - 5%, Zr 1% - 5%, La 0.1% - 5.0%, Y 0.01% - 2.0%, Ce 1.0% - 15.0%, Pt 0 - 500.0 g / t, Pd 30.0 - 3000.0 g / t, and Rh 5.0 - 300.0 g / t.

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