Method for wet enrichment of platinum, palladium and rhodium from automobile three-way waste catalysts

Abstract

The present application relates to a kind of automobile ternary waste catalyst wet enrichment platinum, palladium, rhodium method, comprising the following steps: crushing: ternary waste catalyst is crushed;Fenton oxidation activation: according to material, water, MgCl2, FeCl2 is added into reaction kettle and is stirred uniformly, heating, slowly droping hydrogen peroxide and hydrochloric acid, activation leaching;Oxidation leaching: after activation leaching is completed, hydrochloric acid is added into reaction kettle, slowly droping saturated sodium chlorate solution, oxidation leaching;Filtering one: after oxidation leaching is completed, filter washing is carried out, and filtrate L1 and filter residue S1 are obtained;Replacement enrichment: filtrate L1 is added into stirring tank, then iron powder or iron block is added and stirred to replace noble metal, after replacement, solution is sampled to detect noble metal residual amount, and next step is entered;Filtering two: after replacement is completed, filter washing is carried out, and filtrate L2 and filter residue S2 are obtained.The method solves the shortcomings of high equipment investment, high energy consumption, subsequent processing trouble of rich alloy and the problems of low noble metal recovery rate of wet enrichment process.

Description

Technical Field

[0001] This invention relates to the field of precious metal recovery technology from automotive waste catalysts, specifically to a method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converters. Background Technology

[0002] Automotive three-way catalysts generally use platinum group metals such as platinum, palladium, and rhodium as active components. With the rapid development of my country's automotive industry, the number of cars on the road has been increasing rapidly year by year. At the same time, my country is gradually entering the peak period of car scrapping, and a large number of scrapped car three-way catalysts urgently need to be processed and developed for utilization.

[0003] The platinum group metals (PGMs) content in spent automotive catalysts reaches over 0.1%, hundreds or even thousands of times higher than that of ordinary ores. In my country, 6%–8% of platinum, 75% of palladium, and almost all of rhodium are used in the manufacture of automotive exhaust purification catalysts. The growth in automobile consumption has led to a continuous increase in demand for PGMs. However, my country suffers from a scarcity of PGM resources, a significant supply-demand imbalance, and a high dependence on imports. The explosive growth in the resource volume of spent automotive three-way catalysts represents a mobile mine of PGMs, possessing immense development value.

[0004] The recycling of platinum group metals from waste automotive three-way catalysts is mainly divided into three stages: enrichment, separation, and refining. The primary core step of the entire process is efficient enrichment, which mainly involves two processes: pyrometallurgical and hydrometallurgical methods.

[0005] Currently, most recycling companies both domestically and internationally primarily use pyrometallurgical enrichment processes. Pyrometallurgical enrichment is a process that uses base metals such as iron and copper as collectors to enrich platinum group metals at high temperatures of 1400–1600℃. Its advantages include high recovery rates and large enrichment ratios of platinum group metals, but it also has disadvantages such as specialized equipment, large equipment investment, high energy consumption, and complicated subsequent processing of the enriched metals.

[0006] Hydrometallurgical enrichment involves leaching precious metals from a catalyst at ambient temperature and pressure, followed by selective precipitation to obtain a precious metal-enriched slag. Hydrometallurgical enrichment processes and equipment are simple, energy-efficient, and have low production costs, with straightforward subsequent refining processes. However, existing hydrometallurgical processes suffer from low precious metal leaching rates, particularly for rhodium, which rarely exceeds 80%, resulting in low precious metal recovery rates. Summary of the Invention

[0007] The purpose of this invention is to design a method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, in order to solve the shortcomings of the pyrometallurgical enrichment process mentioned in the background art, such as large investment in equipment, high energy consumption, and troublesome subsequent processing of enriched gold, as well as the problem of low precious metal recovery rate in the wet enrichment process.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0010] a. Crushing: Crushing the ternary waste catalyst into powder;

[0011] b. Fenton oxidation activation: Add the materials and auxiliary materials to the reaction vessel according to the mass ratio of material:water:MgCl2:FeCl2=1:4:1-2:0.2-1, stir and mix well, heat to 50-90℃ and maintain, slowly add hydrogen peroxide and 36% mass fraction hydrochloric acid, and activate and leach for 1-3 hours;

[0012] FeCl2 provides Fe 2+ Under weakly acidic conditions, the reaction with hydrogen peroxide produces FeOOH active ions. These FeOOH active ions have an oxidation potential of 2.73 V under weakly acidic conditions, exhibiting strong oxidizing properties. Magnesium chloride and ferric chloride in the solution provide sufficient chloride ion concentration. Under high chloride ion concentration and strong oxidizing conditions, platinum, palladium, and rhodium are oxidized into chloride complex ions that dissolve into the solution. The reaction is as follows:

[0013]

[0014] During the Fenton reaction, the Fenton reaction enhances the strong oxidizing power, promoting the leaching of platinum, palladium, and rhodium. Additionally, Fe... 3+ Hydrolysis into active ferric hydroxide colloids adsorbs some of the platinum, palladium, and rhodium dissolved in the solution into the ferric hydroxide colloid precipitate, thereby reducing the content of precious metals dissolved in the solution and promoting the oxidation and dissolution of precious metals in the solution. The dissolved precious metals are adsorbed and precipitated by ferric hydroxide colloids, which plays a role in activating the precious metals.

[0015] c. Oxidative leaching: After activation leaching is completed, add 36% hydrochloric acid to the reaction vessel, and slowly add saturated sodium chlorate solution at 70-80℃ for oxidative leaching for 1-2 hours;

[0016] After activation and leaching, hydrochloric acid is added to dissolve the ferric hydroxide precipitate, releasing the active components of the precious metal. Then, saturated sodium chlorate solution is added to oxidize and dissolve the precious metal. Sodium chlorate and hydrochloric acid decompose and have strong oxidizing properties, thereby increasing the solubility of the precious metal.

[0017] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. Filter residue S1 is a mixture of alumina and silica, which is a catalyst support and can be sold externally.

[0018] e. Displacement enrichment: Filtrate L1 is added to a stirring tank, and then iron powder or iron blocks are added and stirred to displace the precious metals, namely platinum, palladium and rhodium. The displacement time is 1-8 hours. After displacement, the solution is sampled to detect the residual amount of precious metals and proceeds to the next step.

[0019] The reaction principle of adding iron powder or iron blocks to displace and enrich precious metals is as follows:

[0020] Fe+Fe 3+ =Fe 2+ ;

[0021]

[0022] f. Filtration 2: After the replacement is completed, filter and wash to obtain filtrate L2 and filter residue S2.

[0023] The main components of the filtrate L2 obtained after iron replacement filtration are still FeCl2 + MgCl2. After adding a small amount of magnesium oxide to adjust the pH of filtrate L2, it can be returned to step b to oxidize and activate the noble metal.

[0024] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste catalyst, step a involves pulverizing the three-way catalytic converter waste catalyst into 40-100 mesh powder to expose the precious metals on the material surface for activation and leaching.

[0025] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, the volume of hydrogen peroxide added per hour in step b is 0.5-2 times the mass value of FeCl2. If it is too fast, the hydrogen peroxide decomposes quickly, resulting in more reagent consumption; if it is too slow, the Fenton oxidation activation will be insufficient.

[0026] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, hydrochloric acid is slowly added dropwise in step b to maintain the pH of the entire reaction system at 1.5-4. If the pH is too low, it will affect the Fenton reaction effect; if it is too high, it will precipitate ferrous iron.

[0027] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, the volume of hydrochloric acid in step c is 0.5-2 times the mass value of the material.

[0028] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, the volume of saturated sodium chlorate solution in step c is 0.1-1 times the mass of the material.

[0029] Furthermore, in the above-mentioned method for wet enrichment of platinum, palladium, and rhodium from automotive three-way catalytic converter waste, the amount of iron powder or iron block added in step e is excessive in order to fully replace the precious metals.

[0030] Furthermore, the above-mentioned method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste also includes step g, replacement of tail liquid reuse: magnesium oxide is added to filtrate L2, the pH is adjusted to >1, and then it is returned to step b for recycling.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. This invention improves the activity of precious metals by setting Fenton oxidation activation, thereby increasing the wet leaching rate and recovery rate of precious metals;

[0033] 2. The Fenton oxidation activation step and the oxidative leaching step of the present invention are completed in the same reactor, which shortens the process flow;

[0034] 3. The amount of enriched slag after iron replacement is small and the enrichment ratio is high, which facilitates subsequent platinum, palladium and rhodium separation and purification, and does not have the problem of difficult handling of ferrosilicon alloys enriched by pyrometallurgy.

[0035] 4. The replacement wastewater from this process can be recycled into the Fenton oxidation activation step, which can reduce wastewater discharge in the process and is environmentally friendly;

[0036] 5. The equipment used in this invention is simple, requires little investment, and has low energy consumption. Attached Figure Description

[0037] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0038] This invention can be implemented in many variations and in various ways, but as one example, a specific embodiment will be described in detail below. The embodiments are not limited to the specific embodiments of the invention disclosed herein, and all variations, equivalents, and alternatives implemented within the scope expressed in the appended claims are included in this scope. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0039] 6 kg of three-way catalyst was taken and ground to 80 mesh using a disc mill sample preparation machine. Samples were taken and analyzed. The main components of the three-way catalyst are shown in Table 1 below:

[0040] Table 1:

[0041] Ingredients <![CDATA[Al2O3]]> <![CDATA[SiO2]]> MgO <![CDATA[ZrO2]]> CeO Pt Pd Rh other Content (g / t) 373000 334000 91000 48000 38000 236 1642 203 114000

[0042] All the ternary spent catalysts used below are derived from this ternary catalyst.

[0043] Example 1

[0044] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0045] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0046] b. Fenton oxidation activation: 1 kg of material powder is put into a 10 L reactor, then 4 L of water, 1 kg of MgCl2 and 200 g of FeCl2 are added and stirred until well mixed. The mixture is heated to 60 °C and maintained at this temperature. Hydrogen peroxide and 36% hydrochloric acid are slowly added dropwise. The hydrogen peroxide drop rate is 150 mL / h and the hydrochloric acid drop rate is maintained at pH 2-3. After 1.5 h of activation leaching, the addition of hydrogen peroxide and hydrochloric acid is stopped.

[0047] c. Oxidative leaching: After activation leaching is completed, add 500 mL of 36% hydrochloric acid to the reaction vessel, heat to 80℃, slowly add 200 mL of saturated sodium chlorate solution, and oxidize and leach for 1 h;

[0048] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. By analyzing and testing filtrate L1 and filter residue S1, the leaching rates of platinum, palladium and rhodium are: platinum 99.1%, palladium 99.4% and rhodium 95.3%.

[0049] e. Displacement enrichment: Filtrate L1 was added to a stirred tank, and then 80g of iron powder was added and stirred to displace the precious metals for 6 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 5.6ppm, palladium 3.8ppm and rhodium 8ppm. Proceed to the next step.

[0050] f. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 23.3g. The contents of platinum, palladium and rhodium are: platinum 0.99%, palladium 7.01% and rhodium 0.827%, and the precious metal enrichment factor is 43 times.

[0051] Example 2 (Case Study of Reusing Replacement Liquid)

[0052] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0053] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0054] b. Fenton oxidation activation: 1 kg of material powder was put into a 10 L reactor, 5 L of filtrate L2 from Example 1 was added, and magnesium oxide was slowly added with stirring to adjust the pH to 3. The mixture was heated to 70 °C and maintained at this temperature. Hydrogen peroxide and 36% hydrochloric acid were slowly added dropwise. The hydrogen peroxide drop rate was 100 mL / h, and the hydrochloric acid drop rate was maintained at pH 2.5-3. After activating and leaching for 2 hours, the addition of hydrogen peroxide and hydrochloric acid was stopped.

[0055] c. Oxidative leaching: After activation leaching is completed, add 500 mL of 36% hydrochloric acid to the reaction vessel, heat to 85℃, slowly add 300 mL of saturated sodium chlorate solution, and oxidize and leach for 1 h;

[0056] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. The leaching rates of platinum, palladium and rhodium in filtrate L1 and filter residue S1 are as follows: platinum 99.2%, palladium 99.5% and rhodium 94.8%.

[0057] e. Displacement enrichment: Filtrate L1 was added to a stirred tank, and then 100g of iron powder was added and stirred to displace the precious metals for 7 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 4.9ppm, palladium 5.3ppm and rhodium 7.9ppm. Proceed to the next step.

[0058] f. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 28.3g. The contents of platinum, palladium and rhodium are: platinum 0.81%, palladium 5.78% and rhodium 0.70%, and the precious metal enrichment factor is 35 times.

[0059] Example 3

[0060] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0061] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0062] b. Fenton oxidation activation: 1 kg of material powder is put into a 10 L reactor, then 4 L of water, 1.2 kg of MgCl2 and 300 g of FeCl2 are added and stirred until well mixed. The mixture is heated to 60 °C and the reaction temperature is maintained at 60 °C. Hydrogen peroxide and 36% hydrochloric acid are slowly added dropwise. The hydrogen peroxide drop rate is 350 mL / h and the hydrochloric acid drop rate is maintained at pH 2-3. After 1.5 h of activation leaching, the addition of hydrogen peroxide and hydrochloric acid is stopped.

[0063] c. Oxidative leaching: After activation leaching is completed, add 1000 mL of 36% hydrochloric acid to the reaction vessel, heat to 80℃, slowly add 300 mL of saturated sodium chlorate solution, and oxidize and leach for 1.5 h;

[0064] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. The leaching rates of platinum, palladium and rhodium in filtrate L1 and filter residue S1 are as follows: platinum 99.3%, palladium 99.6% and rhodium 95.8%.

[0065] e. Displacement enrichment: Filtrate L1 was added to a stirred tank, and then 120g of iron powder was added and stirred to displace the precious metals for 6 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 5.6ppm, palladium 4.8ppm and rhodium 7.5ppm. Proceed to the next step.

[0066] f. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 21.8g. The contents of platinum, palladium and rhodium are: platinum 1.05%, palladium 7.51% and rhodium 0.90%, and the precious metal enrichment factor is 45 times.

[0067] Comparative Example 1

[0068] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0069] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0070] b. Oxidative leaching: 1 kg of material powder is put into a 10 L reactor, 500 mL of 36% hydrochloric acid is added to the reactor, the temperature is raised to 80 °C, and 200 mL of saturated sodium chlorate solution is slowly added dropwise for oxidative leaching for 1 h;

[0071] c. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. The leaching rates of platinum, palladium and rhodium in filtrate L1 and filter residue S1 are as follows: platinum 96.3%, palladium 97.1% and rhodium 90.3%.

[0072] d. Displacement enrichment: Filtrate L1 was added to a stirred tank, and then 80g of iron powder was added and stirred to displace the precious metals for 6 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 6.1ppm, palladium 5.3ppm and rhodium 9.2ppm. Proceed to the next step.

[0073] e. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 20.3g. The contents of platinum, palladium and rhodium are: platinum 0.97%, palladium 4.92% and rhodium 0.81%, and the precious metal enrichment factor is 21 times.

[0074] Comparative Example 2

[0075] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0076] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0077] b. Fenton oxidation activation: 1 kg of material powder is put into a 10 L reactor, then 4 L of water, 1 kg of MgCl2 and 200 g of FeCl2 are added and stirred until well mixed. The mixture is heated to 60 °C and maintained at this temperature. Hydrogen peroxide and 36% hydrochloric acid are slowly added dropwise. The hydrogen peroxide drop rate is 50 mL / h and the hydrochloric acid drop rate is maintained at pH 2-3. After 1.5 h of activation leaching, the addition of hydrogen peroxide and hydrochloric acid is stopped.

[0078] c. Oxidative leaching: After activation leaching is completed, add 500 mL of 36% hydrochloric acid to the reaction vessel, heat to 80℃, slowly add 200 mL of saturated sodium chlorate solution, and oxidize and leach for 1 h;

[0079] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. The leaching rates of platinum, palladium and rhodium in filtrate L1 and filter residue S1 are as follows: platinum 97.2%, palladium 98.9% and rhodium 93.2%.

[0080] e. Displacement enrichment: Filtrate L1 was added to a stirred tank, and then 80g of iron powder was added and stirred to displace the precious metals for 6 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 5.1ppm, palladium 7.9ppm and rhodium 8.9ppm. Proceed to the next step.

[0081] f. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 15.4g. The contents of platinum, palladium and rhodium are: platinum 1.01%, palladium 6.85% and rhodium 0.8%, and the precious metal enrichment factor is 25 times.

[0082] Comparative Example 3

[0083] A method for wet enrichment of platinum, palladium, and rhodium in automotive three-way catalytic converter waste includes the following steps:

[0084] a. Crushing: Use the above-mentioned pre-crushed 80-mesh ternary catalyst powder;

[0085] b. Fenton oxidation activation: 1 kg of material powder is put into a 10 L reactor, then 4 L of water, 1 kg of MgCl2 and 200 g of FeCl2 are added and stirred until well mixed. The mixture is heated to 60 °C and maintained at this temperature. Hydrogen peroxide and 36% hydrochloric acid are slowly added dropwise. The hydrogen peroxide drop rate is 150 mL / h and the hydrochloric acid drop rate is maintained at pH 5-7. After 1.5 h of activation leaching, the addition of hydrogen peroxide and hydrochloric acid is stopped.

[0086] c. Oxidative leaching: After activation leaching is completed, add 500 mL of 36% hydrochloric acid to the reaction vessel, heat to 80℃, slowly add 200 mL of saturated sodium chlorate solution, and oxidize and leach for 1 h;

[0087] d. Filtration 1: After the oxidation leaching is completed, the filter is washed to obtain filtrate L1 and filter residue S1. The leaching rates of platinum, palladium and rhodium in filtrate L1 and filter residue S1 are as follows: platinum 68.2%, palladium 65% and rhodium 60.2%.

[0088] e. Displacement enrichment: Filtrate L1 was added to a stirring tank, and then 80g of iron powder was added and stirred to displace the precious metals for 6 hours. After displacement, the solution was sampled and tested. The contents of platinum, palladium and rhodium in the solution were measured to be: platinum 10ppm, palladium 15ppm and rhodium 23.2ppm. Proceed to the next step.

[0089] f. Filtration 2: After the replacement is completed, the filter is washed to obtain filtrate L2 and filter residue S2. The filter residue S2 is dried and weighed to be 15.3g. The contents of platinum, palladium and rhodium are: platinum 0.71%, palladium 4.5% and rhodium 0.53%, and the precious metal enrichment factor is 13 times.

[0090] The leaching rate and recovery rate data of the above embodiments and comparative examples are shown in Table 2 below.

[0091] Table 2:

[0092]

[0093]

[0094] As can be seen from Table 2 above, the overall leaching rate and recovery rate of Examples 1-3 are better than those of Comparative Examples 1-3. Specifically, Comparative Example 1 lacks the Fenton oxidation activation step compared to Example 1, resulting in a lower leaching rate of platinum, palladium, and rhodium, and consequently, a lower recovery rate. In Comparative Example 2, compared to Example 1, the hydrogen peroxide droplet acceleration rate is too low, leading to insufficient Fenton oxidation activation and consequently, poorer leaching and recovery rates of the precious metals platinum, palladium, and rhodium. In Comparative Example 3, compared to Example 1, the solution reaction pH is 5-7, which is too high, causing ferrous iron to precipitate and resulting in a poorer Fenton reaction effect, thus lower leaching and recovery rates of platinum, palladium, and rhodium.

[0095] This invention enhances the activity of precious metals through Fenton oxidation activation, thereby increasing the wet leaching rate and recovery rate of precious metals. Furthermore, the Fenton oxidation activation step and the oxidative leaching step are completed in the same reactor, shortening the process flow. The filter residue obtained from the first filtration is a mixture of alumina and silica, a catalyst support, which can be sold to generate economic benefits. The filtrate obtained from the first filtration, after iron replacement, has a small amount of enriched residue and a high enrichment factor, facilitating subsequent platinum, palladium, and rhodium separation and purification, and avoiding the difficult-to-handle problem of ferrosilicon alloys in pyrometallurgical enrichment of golds. The filtrate obtained from the second filtration, i.e., the replacement wastewater, can be recycled back to the Fenton oxidation activation step after pH adjustment, as shown in Example 2, to reduce wastewater discharge in the process, making it environmentally friendly. The equipment used in the entire process is simple, with advantages of low investment and low energy consumption.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for wet enrichment of platinum, palladium, rhodium from automobile three-way waste catalysts, characterized in that, The method comprises the following steps: a. crushing: crushing the ternary waste catalyst into powder; b. Fenton oxidation activation: adding the materials and auxiliary materials into the reaction kettle in a mass ratio of materials: water: MgCl2: FeCl2 = 1:4:1-2:0.2-1, stirring and mixing uniformly, heating to 50-90℃ and keeping, slowly adding hydrogen peroxide and 36% mass fraction hydrochloric acid, and activating leaching for 1-3h; wherein the volume of hydrogen peroxide added per hour is 0.5-2 times the mass value of FeCl2; slowly adding hydrochloric acid to maintain the pH of the whole reaction system at 1.5-4; c. oxidation leaching: after the activation leaching is completed, adding 36% mass fraction hydrochloric acid into the reaction kettle, slowly adding saturated sodium chlorate solution at 70-80℃, and oxidation leaching for 1-2h; d. filtration one: after the oxidation leaching is completed, filtering and washing to obtain filtrate L1 and residue S1; e. displacement enrichment: adding the filtrate L1 into the stirring tank, then adding iron powder or iron block to stir and displace noble metals, the displacement time being 1-8h, sampling and detecting the residual amount of noble metals after displacement, and entering the next step; f. filtration two: after the displacement is completed, filtering and washing to obtain filtrate L2 and residue S2.

2. The method of claim 1, wherein the automobile three-way exhaust catalyst is a catalyst for purifying exhaust gas of an internal combustion engine, and the exhaust gas is exhaust gas of a gasoline engine. In step a, the ternary waste catalyst is crushed into 40-100 mesh powder.

3. The method of claim 1, wherein the automobile three-way exhaust catalyst is a catalyst for purifying exhaust gas of an automobile, and the automobile three-way exhaust catalyst is a catalyst for purifying exhaust gas of a gasoline engine automobile. In step c, the volume of hydrochloric acid is 0.5-2 times the mass value of the materials.

4. The method of claim 1, wherein the automobile three-way exhaust catalyst is a catalyst for purifying exhaust gas of an automobile, and the automobile three-way exhaust catalyst is a catalyst for purifying exhaust gas of a gasoline engine automobile. In step c, the volume of saturated sodium chlorate solution is 0.1-1 times the mass value of the materials.

5. The method of claim 1, wherein the automobile three-way exhaust catalyst is a platinum, palladium, and rhodium rich catalyst. In step e, the added amount of iron powder or iron block is excessive.

6. The method of claim 1, wherein the automobile three-way exhaust catalyst is a platinum, palladium, rhodium-rich catalyst. It also comprises step g displacement tail liquid recycling: adding magnesium oxide into the filtrate L2, adjusting the pH to be greater than 1, and returning to step b for recycling.

Images