A method for enriching secondary resources of platinum group metals using electromagnetic fields

Abstract

The present invention relates to a method for enriching secondary resources of platinum group metals using an electromagnetic field, and belongs to the technical field of platinum group metal resource recovery. The present invention uniformly mixes platinum group metal-containing waste, a collector, a reducing agent, an additive, and a binder to obtain a mixture; wet-grinding the mixture to obtain a wet-milled mixture, pelletizing the wet-milled mixture, and drying to obtain platinum group metal-containing waste pellets; under a protective atmosphere, the platinum group metal-containing waste pellets are subjected to electromagnetic enrichment to obtain reduced pellets; and magnetic separation is used to recover ferroalloy-PGMs in the reduced pellets to achieve enrichment of platinum group metals. The electromagnetic effect of the electromagnetic field of the present invention causes the collector ferroalloy grains to migrate and grow rapidly during the reduction process due to the electromagnetic force, while significantly increasing the collector grain size, improving the collector's ability to capture PGMs, and increasing the recovery rate of PGMs, so that the solid-state method for recovering secondary resources of platinum group metals has practical application value.

Description

Technical Field

[0001] The invention relates to a method for enriching secondary resources of platinum group metals using an electromagnetic field, belonging to the technical field of platinum group metal resource recovery. Background Art

[0002] Platinum group metals (PGMs) have stable chemical properties, excellent catalytic activity, and excellent electrical and thermal conductivity. They are widely used in automotive exhaust purification, electronics, chemical catalysis, and aerospace. PGMs are relatively abundant in secondary resources, especially in spent automotive exhaust catalysts, petrochemical waste catalysts, and fine chemical waste catalysts, with PGM content far exceeding that of their original ore, making them highly valuable for recycling.

[0003] Currently developed spent automotive catalysts basically use pyrometallurgical smelting enrichment processes to recover platinum group metals, but the existing pyrometallurgical enrichment technology still has problems such as long enrichment cycle, high energy consumption, and low PGMs content in ferroalloys. Summary of the Invention

[0004] In view of the existing technology of using pyrometallurgical smelting enrichment process to recover platinum group metals, which has problems such as long enrichment cycle, high energy consumption, and low PGMs content in ferroalloys, the present invention proposes a method for enriching secondary resources of platinum group metals using electromagnetic field. During the electromagnetic field enrichment process, the electromagnetic effect promotes the migration and growth of ferroalloy collector grains (iron Fe, nickel Ni, cobalt Co, manganese Mn), thereby enhancing the collector's ability to capture platinum group metals; a composite collector composed of iron concentrate and waste ternary precursor is used, and the coupling effect between iron Fe, nickel Ni, cobalt Co, and manganese Mn can be utilized to enhance the electromagnetic enrichment effect.

[0005] A method for enriching secondary resources of platinum group metals using an electromagnetic field, comprising the following steps:

[0006] (1) uniformly mixing platinum group metal-containing waste, a collector, a reducing agent, an additive, and a binder to obtain a mixture;

[0007] (2) wet-grinding the mixture to obtain a wet-grinded mixture, pelletizing the wet-grinded mixture, and drying the mixture to obtain pellets containing platinum group metal waste;

[0008] (3) Under a protective atmosphere, the platinum group metal waste pellets are electromagnetically enriched in a temperature-controlled electromagnetic field induction heating furnace to obtain reduced pellets;

[0009] (4) Magnetic separation is used to recover ferroalloy-PGMs from the reduced pellets to achieve the enrichment of platinum group metals.

[0010] Preferably, the platinum group metal-containing waste material in step (1) is automobile exhaust waste catalyst, petrochemical waste catalyst or fine chemical waste catalyst containing platinum group metals.

[0011] Preferably, the collector in step (1) is composed of iron ore concentrate and waste ternary precursor powder containing nickel, cobalt and manganese, and the mass ratio of iron ore concentrate to waste ternary precursor powder is 39~49:1; the reducing agent is coke powder or anthracite, the additive is one or more of quicklime, limestone, slaked lime, borax and sodium carbonate, and the binder is one or more of inorganic binders or organic binders.

[0012] More preferably, the waste ternary precursor powder is one or more of NCM811 precursor, NCM622 precursor, and NCM523 precursor, the inorganic binder is water glass and / or bentonite, and the organic binder is one or more of humic acid, sodium carboxymethyl cellulose, starch, and dextrin.

[0013] Preferably, the mass ratio of the collector to the platinum group metal-containing waste is 1.5-2:1, the mass ratio of the platinum group metal-containing waste to the reducing agent is 4-4.5:1, the mass ratio of the platinum group metal-containing waste to the additive is 11-15:1, and the mass ratio of the platinum group metal-containing waste to the binder is 30-35:1.

[0014] The strength of the platinum group metal waste pellets in step (2) is not less than 200N / P.

[0015] Preferably, the electromagnetic enrichment method in step (3) specifically comprises:

[0016] At an electromagnetic field frequency of 10-30kHz, the temperature is raised from 400-600°C to 700-900°C to achieve variable temperature electromagnetic enrichment for 20-30 minutes. During this low-temperature stage, the low-frequency electromagnetic field has a stronger penetration depth and can more effectively act on the interior of the reduced pellets, causing the primary crystals of the metallic iron alloy produced by the reduction to form in large quantities on the surface of the capture agent, laying the foundation for the subsequent stages.

[0017] Under an electromagnetic field frequency of 40-60 kHz, the temperature is raised from 700-900°C to 1100-1300°C for 20-30 minutes to achieve variable temperature electromagnetic enrichment. During this medium temperature stage, the collector ferroalloy grains begin to grow rapidly. The moderate frequency provides moderate electromagnetic and magnetic forces, accelerating the migration of particles in the ferroalloy grains, achieving rapid growth of the ferroalloy grains and efficient capture of PGMs.

[0018] The electromagnetic enrichment is carried out at a constant temperature of 1100-1300°C for 80-180 minutes at an electromagnetic field frequency of 80-100kHz. During this high-temperature constant stage, the high-frequency electromagnetic field can generate a stronger local electromagnetic force density, causing the iron alloy grains generated in the low and medium magnetic fields to migrate and aggregate, allowing the iron alloy grains to fully grow to the target size (tens or even hundreds of microns). At the same time, it ensures that the PGMs have enough time to reach distribution equilibrium in the iron alloy phase through diffusion, achieving deep capture.

[0019] The electromagnetic field frequency is reduced to 60-70kHz, and constant temperature electromagnetic enrichment is carried out at a temperature of 1100-1300℃ for 50-60min. During this high-temperature constant stage, the grains have fully grown, and the frequency is moderately reduced (but stirring is still maintained) to allow PGMs to settle on the ferroalloy grains and allow the ferroalloy grains to continue to aggregate and grow, creating a more favorable phase distribution for subsequent magnetic separation (large particles are easier to separate), stabilizing the grain structure, reducing internal defects, and ensuring that PGMs are fully homogenized in the ferroalloy phase.

[0020] In the step (4), the grain size of the ferroalloy-PGMs is 50-200 μm.

[0021] The principle behind the electromagnetic field enrichment of secondary PGM resources is that low PGM recovery rates are often caused by low collector efficiency. Low PGM content in ferroalloys is a major challenge in the pyrometallurgical enrichment of secondary PGM resources. Electromagnetic field enrichment promotes the growth of ferroalloy collector grains (Fe / Ni / Co / Mn) through the electromagnetic effect of the electromagnetic field. The alternating electromagnetic field induces an induced current within the collector grains, which is perpendicular to the magnetic field and interacts with the alternating electromagnetic field to generate an electromagnetic force (Lorentz force). Furthermore, the collector ferroalloy grains are magnetized in the magnetic field, and the interaction between the magnetized ferroalloy grains and the magnetic field results in a magnetic force. Due to the different electrical conductivity and magnetic susceptibility of the collector iron alloy grains and non-metallic grains, the electromagnetic force and magnetic force they are subjected to in the electromagnetic field are of different magnitude and direction. The collector iron alloy grains migrate and aggregate under the action of electromagnetic and magnetic forces in the electromagnetic field. The migration and aggregation enable the iron alloy grains to better capture platinum group metals during movement. In the absence of the electromagnetic field, the iron alloy grains only grow in a fixed position and do not have the migration and aggregation process. Therefore, the capture effect of platinum group metals is poor, resulting in a low platinum group metal recovery rate; the collector grain size after aggregation in the electromagnetic field is larger than the iron alloy grain size without the electromagnetic field. The large-sized iron alloy grains are more easily recovered in the magnetic separation process, making the platinum group metal recovery rate of the electromagnetic field enrichment method higher than that of the method without electromagnetic enrichment; electromagnetic enrichment realizes the increase of the collector iron alloy grain size and migration and aggregation, significantly improves the capture effect of the collector, increases the platinum group metal content in the iron alloy, and increases the recovery rate of Fe-PGMs alloy in the magnetic separation stage.

[0022] During electromagnetic enrichment, the collector iron alloy grains (Fe / Ni / Co / Mn) preferentially form at defects in the magnetite lattice. Initially, these grains form at numerous locations and exhibit a fragile structure. Therefore, low-frequency electromagnetic field and variable-temperature electromagnetic enrichment are required to ensure the mass formation of primary collector crystals during low-temperature enrichment. As the electromagnetic enrichment temperature increases, the collector iron alloy grains continue to grow. At this point, high-frequency electromagnetic field and constant-temperature electromagnetic enrichment facilitate rapid growth, migration, and aggregation of the collector grains, improving their efficiency in capturing platinum group metals.

[0023] The mechanism chain of the electromagnetic field enrichment of secondary resources of platinum group metals in the present invention is: alternating electromagnetic field → generation of Lorentz force (electromagnetic force) → driving the movement of ferroalloy grains → substantially increasing the contact frequency between ferroalloy grains → providing kinetic energy to overcome aggregation resistance → efficient aggregation → substantially increasing the size of ferroalloy grains → substantially increasing the contact opportunities between ferroalloy and PGMs particles / atoms → strengthening the diffusion and mass transfer of PGMs into ferroalloy grains → significantly improving the capture ability and dissolution rate of ferroalloy grains for PGMs → ultimately forming large-sized, PGMs-rich ferroalloy grains → efficient separation through magnetic separation → achieving high recovery rate enrichment of platinum group metals.

[0024] The beneficial effects of the present invention are:

[0025] (1) The present invention uses a composite collector composed of iron concentrate and waste ternary precursor, and utilizes the coupling effect between metals such as iron, nickel, cobalt, and manganese to enhance the electromagnetic enrichment effect;

[0026] (2) The present invention uses an electromagnetic field enrichment method to recover platinum group metals from platinum group metal-containing waste materials. The collector can achieve efficient enrichment of platinum group metals at a low temperature of 1100-1300°C (the traditional smelting enrichment temperature is 1400-1600°C), which can significantly reduce the energy consumption of the platinum group metal enrichment process, improve the platinum group metal enrichment efficiency and the platinum group metal content in the ferroalloy, and increase the platinum group metal recovery rate;

[0027] (3) The traditional enrichment method of platinum group metal waste is to use heat treatment without the action of electromagnetic field. The collector grains are generated and grown at the defects of magnetite lattice. There is no migration and aggregation process, and the growth of grain size is limited. However, under the action of electromagnetic field, the collector grains are not only affected by thermal energy, but also by electromagnetic force and magnetic force. The collector grains grow due to migration and aggregation. This has a significant improvement effect on the capture and recovery of platinum group metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the device for enriching secondary resources of platinum group metals using electromagnetic fields;

[0029] Figure 2 Comparison of the particle size of the collectors in Comparative Example 1 and Example 3, (a) without electromagnetic field, (b) with electromagnetic field;

[0030] Figure 3 This is a statistical diagram of the size of the collector crystals in Comparative Example 1;

[0031] Figure 4 This is a statistical diagram of the size of the collector grains enriched by the electromagnetic field in Example 3. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0033] The schematic diagram of the device for electromagnetic field enrichment of secondary resources of platinum group metals of the present invention is shown in Figure 1 Under a protective atmosphere, platinum group metal scrap pellets are electromagnetically enriched (in a temperature-controlled electromagnetic field induction heating furnace) to obtain reduced pellets. When an alternating electromagnetic field is applied, the collector ferroalloy produced by the reduction is a good conductor, while the surrounding slag is a relatively insulator (or has extremely poor conductivity). The electromagnetic field exerts an electromagnetic effect on the ferroalloy grains. According to the Lorentz force law, a strong electromagnetic force is generated inside and around each conductive ferroalloy grain. The direction of the electromagnetic force is alternating (depending on the direction of the electromagnetic field), but its net effect is to drive the ferroalloy grains to migrate. The Lorentz force acts on the ferroalloy grains, causing adjacent ferroalloy grains to aggregate and contact. This movement is not the isolated behavior of a single grain. A large number of grains are simultaneously subjected to force movement, resulting in migration and aggregation within the entire melt, which significantly increases the collision frequency and contact opportunities between different ferroalloy grains and between ferroalloy grains and dispersed PGMs particles / atoms. When two ferroalloy grains come into contact, the energy barrier formed by overcoming surface tension is overcome and they merge into a larger grain; driven by electromagnetic force, the grains can more easily overcome the surface tension resistance during collision, significantly improving the aggregation efficiency; reducing the physical barriers to aggregation and capture; collision and aggregation allow the originally small ferroalloy grains to grow into larger grains, thereby greatly increasing the grain size; and the dispersed PGMs atoms or tiny particles are "captured" by the ferroalloy grains that are more easily moved. Once they contact the surface of the ferroalloy grains, the PGMs will quickly dissolve into the molten ferroalloy phase (capture). The electromagnetic force accelerates the diffusion of PGMs inside the ferroalloy, making its distribution more uniform and avoiding local saturation, significantly improving the collector (ferroalloy)'s ability to capture PGMs, and increasing the rate and degree of transfer of PGMs from the slag phase to the alloy phase, ensuring that more PGMs are "collected" into the growing collector ferroalloy grains.

[0034] Example 1: In this example, the platinum group metal-containing waste material is a PGMs-containing waste catalyst, which contains Pt78g / t, Pd1596g / t, and Rh207g / t;

[0035] A method for enriching secondary resources of platinum group metals using an electromagnetic field, comprising the following steps:

[0036] (1) Platinum group metal waste (including PGMs waste catalyst), collector (iron concentrate and waste ternary precursor powder in a mass ratio of 49:1), reducing agent (coke powder), additive (quicklime), and binder (sodium carboxymethyl cellulose and starch) are uniformly mixed to obtain a mixture; based on the mass of the mixture as 100%, the mixture contains 35wt% of PGMs waste catalyst, 53wt% of collector, 8wt% of reducing agent, 3wt% of additive, and 1wt% of binder; the waste ternary precursor powder is NCM523;

[0037] (2) The mixture was wet-milled for 10 min to obtain a wet-milled mixture, the wet-milled mixture was pressed under a pressure of 500 MPa to produce balls (diameter 10-14 mm), and dried to obtain platinum group metal waste pellets (drop strength of 12 times / 1 m, compressive strength of 241 N / P);

[0038] (3) Under a protective atmosphere (nitrogen), the platinum group metal waste pellets are subjected to electromagnetic enrichment (temperature electromagnetic field controllable induction heating furnace) to obtain reduced pellets, and the pulverization rate of the reduced pellets is 7.6%; the electromagnetic enrichment method specifically includes:

[0039] Under the electromagnetic field frequency of 10kHz, the temperature was raised from 400℃ to 700℃ to achieve variable temperature electromagnetic enrichment for 20min;

[0040] Under the electromagnetic field frequency of 40kHz, the temperature was raised from 700℃ to 1100℃ to achieve variable temperature electromagnetic enrichment for 30min;

[0041] The electromagnetic field frequency was 80kHz and the temperature was 1100℃ for 80min.

[0042] The electromagnetic field frequency was reduced to 60 kHz, and constant temperature electromagnetic enrichment was carried out at 1100°C for 50 min.

[0043] (4) After the reduced pellets are cooled to room temperature, they are ground in a ball mill for 20 min, and the ferroalloy-PGMs in the reduced pellets are recovered by magnetic separation (dry electromagnetic separator with a magnetic field strength of 1 T) to achieve the enrichment of platinum group metals;

[0044] After testing, the average grain size of the ferroalloy-PGMs in this embodiment was 71.64 μm, the recovery rate of metallic iron was 95.26%, the recovery rate of Pt was 97.86%, the comprehensive recovery rate of nickel, cobalt and manganese was 91.55%, the recovery rate of Pd was 96.47%, and the recovery rate of Rh was 97.68%.

[0045] Example 2: In this example, the platinum group metal-containing waste material is a PGMs-containing waste catalyst, which contains Pt69g / t, Pd1745g / t, and Rh238g / t;

[0046] A method for enriching secondary resources of platinum group metals using an electromagnetic field, comprising the following steps:

[0047] (1) Platinum group metal waste (including PGMs waste catalyst), collector (iron concentrate and waste ternary precursor powder in a mass ratio of 47:1), reducing agent (coke powder), additive (quicklime and borax), and binder (water glass) are uniformly mixed to obtain a mixture; based on the mass of the mixture as 100%, the mixture contains 33wt% of PGMs waste catalyst, 55wt% of collector, 8wt% of reducing agent, 3wt% of additive, and 1wt% of binder; the waste ternary precursor powder is NCM622;

[0048] (2) The mixture was wet-milled for 10 min to obtain a wet-milled mixture, the wet-milled mixture was pressed under a pressure of 500 MPa to produce balls (diameter 10-14 mm), and dried to obtain platinum group metal waste pellets (drop strength of 11 times / 1 m, compressive strength of 217 N / P);

[0049] (3) Under a protective atmosphere (argon), the platinum group metal waste pellets are subjected to electromagnetic enrichment (temperature electromagnetic field controllable induction heating furnace) to obtain reduced pellets, and the pulverization rate of the reduced pellets is 8.5%; the electromagnetic enrichment method specifically includes:

[0050] Under the electromagnetic field frequency of 20kHz, the temperature was raised from 500℃ to 900℃ to achieve variable temperature electromagnetic enrichment for 30min;

[0051] Under the electromagnetic field frequency of 50kHz, the temperature was raised from 900℃ to 1200℃ to achieve variable temperature electromagnetic enrichment for 20min;

[0052] The electromagnetic field was concentrated at a constant temperature of 1200°C for 140 min at an electromagnetic field frequency of 90 kHz.

[0053] The electromagnetic field frequency was reduced to 60 kHz, and constant temperature electromagnetic enrichment was carried out at 1200°C for 50 min.

[0054] (4) After the reduced pellets are cooled to room temperature, they are ground in a ball mill for 20 min, and the ferroalloy-PGMs in the reduced pellets are recovered by magnetic separation (dry electromagnetic separator with a magnetic field strength of 1 T) to achieve the enrichment of platinum group metals;

[0055] After testing, the average grain size of the ferroalloy-PGMs in this embodiment was 93.06 μm, the recovery rate of metallic iron was 97.17%, the recovery rate of Pt was 98.81%, the comprehensive recovery rate of nickel, cobalt and manganese was 95.72%, the recovery rate of Pd was 96.73%, and the recovery rate of Rh was 97.95%.

[0056] Example 3: In this example, the platinum group metal-containing waste material is a PGMs-containing waste catalyst, which contains Pt73g / t, Pd1556g / t, and Rh197g / t.

[0057] A method for enriching secondary resources of platinum group metals using an electromagnetic field, comprising the following steps:

[0058] (1) Platinum group metal waste (including PGMs waste catalyst), collector (iron concentrate and waste ternary precursor powder in a mass ratio of 39:1), reducing agent (anthracite), additives (quicklime and sodium carbonate), and binder (humic acid and dextrin) are uniformly mixed to obtain a mixture; based on the mass of the mixture as 100%, the mixture contains 30wt% of PGMs waste catalyst, 60wt% of collector, 7wt% of reducing agent, 2wt% of additive, and 1wt% of binder; the waste ternary precursor powder is NCM811;

[0059] (2) The mixture was wet-milled for 10 min to obtain a wet-milled mixture, the wet-milled mixture was pressed under a pressure of 500 MPa to produce balls (diameter 10-14 mm), and dried to obtain platinum group metal waste pellets (drop strength of 12 times / 1 m, compressive strength of 228 N / P);

[0060] (3) Under a protective atmosphere (argon), the platinum group metal waste pellets are subjected to electromagnetic enrichment (temperature electromagnetic field controllable induction heating furnace) to obtain reduced pellets, and the pulverization rate of the reduced pellets is 8.7%; the electromagnetic enrichment method specifically includes:

[0061] Under the electromagnetic field frequency of 30kHz, the temperature was raised from 600℃ to 900℃ to achieve variable temperature electromagnetic enrichment for 30min;

[0062] Under the electromagnetic field frequency of 60kHz, the temperature was raised from 900℃ to 1300℃ to achieve variable temperature electromagnetic enrichment for 30min;

[0063] The electromagnetic enrichment was carried out at a constant temperature of 1300°C for 180 min at an electromagnetic field frequency of 100 kHz.

[0064] The electromagnetic field frequency was reduced to 70 kHz, and constant temperature electromagnetic enrichment was carried out at 1300°C for 60 min.

[0065] (4) After the reduced pellets are cooled to room temperature, they are ground in a ball mill for 20 min, and the ferroalloy-PGMs in the reduced pellets are recovered by magnetic separation (dry electromagnetic separator with a magnetic field strength of 1 T) to achieve the enrichment of platinum group metals;

[0066] The average grain size of the ferroalloy-PGMs in this embodiment was 142.57 μm (see Figure 2 and 4), the recovery rate of metallic iron is 98.15%, the recovery rate of Pt is 98.85%, the comprehensive recovery rate of nickel, cobalt and manganese is 96.28%, the recovery rate of Pd is 97.21%, and the recovery rate of Rh is 98.03%.

[0067] Comparative Example 1: The platinum group metal-containing waste material in this comparative example is a PGMs-containing waste catalyst, which contains Pt73g / t, Pd1556g / t, and Rh197g / t;

[0068] The method for enriching secondary resources of platinum group metals using a non-electromagnetic field, specifically comprising the following steps:

[0069] (1) Platinum group metal waste (including PGMs waste catalyst), collector (iron concentrate and waste ternary precursor powder in a mass ratio of 39:1), reducing agent (anthracite), additives (quicklime and sodium carbonate), and binder (humic acid and dextrin) are uniformly mixed to obtain a mixture; based on the mass of the mixture as 100%, the mixture contains 30wt% of PGMs waste catalyst, 60wt% of collector, 7wt% of reducing agent, 2wt% of additive, and 1wt% of binder; the waste ternary precursor powder is NCM811;

[0070] (2) The mixture was wet-milled for 10 min to obtain a wet-milled mixture, the wet-milled mixture was pressed under a pressure of 500 MPa to produce balls (diameter 10-14 mm), and dried to obtain platinum group metal waste pellets (drop strength of 12 times / 1 m, compressive strength of 228 N / P);

[0071] (3) Under a protective atmosphere (argon), the PGM-containing waste pellets were heated to 1300°C in a muffle furnace and concentrated at constant temperature for 240 min to obtain reduced pellets, with a pulverization rate of 8.9%; (4) After the reduced pellets were cooled to room temperature, they were ground in a ball mill for 20 min, and magnetic separation (dry electromagnetic separator with a magnetic field strength of 1 T) was used to recover the ferroalloy-PGMs in the reduced pellets to achieve enrichment of PGMs;

[0072] The average grain size of the ferroalloy-PGMs in this embodiment was 49.51 μm (see Figure 2 and 3 ), the recovery rate of metallic iron is 93.18%, the recovery rate of Pt is 95.21%, the comprehensive recovery rate of nickel, cobalt and manganese is 89.44%, the recovery rate of Pd is 93.24%, and the recovery rate of Rh is 94.87%;

[0073] Platinum group metals are rare and precious metals and are expensive (the price of Pt and Pd is greater than RMB 200 / g). The results of Example 3 and Comparative Example 1 show that electromagnetic enrichment has a higher recovery rate of platinum group metals than conventional pyrometallurgical enrichment, and has obvious economic benefits.

[0074] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for enriching secondary resources of platinum group metals using an electromagnetic field, characterized in that: The specific steps are as follows: (1) Platinum group metal waste, a collector, a reducing agent, an additive, and a binder are uniformly mixed to obtain a mixture; the collector is composed of iron ore concentrate and waste ternary precursor powder containing nickel, cobalt, and manganese, and the mass ratio of the iron ore concentrate to the waste ternary precursor powder is 39-49:1; the additive is one or more of quicklime, limestone, slaked lime, borax, and sodium carbonate; (2) wet-grinding the mixture to obtain a wet-grinded mixture, pelletizing the wet-grinded mixture, and drying the mixture to obtain pellets containing platinum group metal waste; (3) Under a protective atmosphere, the platinum group metal waste pellets are electromagnetically enriched to obtain reduced pellets; The electromagnetic enrichment method specifically comprises: Under the electromagnetic field frequency of 10~30kHz, the temperature is raised from 400~600℃ to 700~900℃ to achieve variable temperature electromagnetic enrichment for 20~30min; Under the electromagnetic field frequency of 40-60kHz, the temperature is raised from 700-900℃ to 1100-1300℃ to achieve variable temperature electromagnetic enrichment for 20-30min; Electromagnetic enrichment was carried out at a constant temperature of 1100-1300°C for 80-180 min at an electromagnetic field frequency of 80-100 kHz; The electromagnetic field frequency is reduced to 60-70 kHz, and the electromagnetic enrichment is carried out at a constant temperature of 1100-1300°C for 50-60 minutes; (4) Magnetic separation is used to recover ferroalloy-PGMs from the reduced pellets to achieve the enrichment of platinum group metals.

2. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: The platinum group metal-containing waste material in step (1) is automobile exhaust waste catalyst, petrochemical waste catalyst or fine chemical waste catalyst containing platinum group metals.

3. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: In step (1), the reducing agent is coke powder or anthracite, and the binder is one or more of an inorganic binder or an organic binder.

4. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 3, characterized in that: The waste ternary precursor powder is one or more of NCM811 precursor, NCM622 precursor and NCM523 precursor; the inorganic binder is water glass and / or bentonite; and the organic binder is one or more of humic acid, sodium carboxymethyl cellulose, starch and dextrin.

5. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: The mass ratio of the collector to the platinum group metal-containing waste is 1.5~2:1, the mass ratio of the platinum group metal-containing waste to the reducing agent is 4~4.5:1, the mass ratio of the platinum group metal-containing waste to the additive is 11~15:1, and the mass ratio of the platinum group metal-containing waste to the binder is 30~35:

1.

6. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: The strength of the platinum group metal waste pellets in step (2) is not less than 200N / P.

7. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: The pulverization rate of the reduced pellets in step (3) is not higher than 20%.

8. The method for enriching secondary resources of platinum group metals using an electromagnetic field according to claim 1, characterized in that: The ferroalloy-PGMs grain size in the reduced pellets in step (4) is 50-200 μm.

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