Method for directional capture of platinum group metals by reduction smelting of spent three-way catalysts and waste circuit boards

Abstract

The method comprises the following steps: step 1), obtaining carbon black-rich copper and waste three-way catalyst powder raw materials; step 2), mixing the carbon black-rich copper with the waste three-way catalyst powder raw materials, adding a slagging agent, and performing reduction smelting; step 3), during the reduction smelting process, spraying fuel and oxygen-rich air into the smelting furnace, adding a reducing agent into the molten material in the furnace, and obtaining crude copper liquid; step 4), performing pyrorefining on the crude copper liquid, adding silicon dioxide, and blowing air into the furnace, and obtaining copper liquid; step 5), casting the copper liquid into copper anode plates rich in platinum group metals; step 6), performing electrolytic refining on the copper anode plates rich in platinum group metals to obtain high-purity cathode copper, and wet-step recovering platinum group metals from electrolytic anode sludge. After the copper liquid rich in platinum group metals is discharged, the iron and lead in the crude copper liquid are removed by using pyrorefining, so that the influence of impurity metal elements on the electrolytic refining process is avoided.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature metallurgical technology, specifically relating to a method for the directional capture of platinum group metals through the reduction smelting of waste ternary catalysts and waste circuit boards. Background Technology

[0002] Automotive exhaust three-way catalysts mainly consist of three parts: a cordierite support (2MgO·2Al2O3·5SiO2), a highly active γ-Al2O3 coating on the support surface, and catalytically active components containing Pt, Pd, and Rh in the coating. During use, the γ-Al2O3 in the coating transforms into the more structurally stable α-Al2O3, causing the platinum group metals to be deeply encapsulated by aluminum and magnesium impurities on the support, making smelting and extraction difficult. Industrially, the recycling of spent three-way catalysts (SAC) generally employs pyrometallurgical processes to enrich the platinum group metals into the metallic phase, removes most impurities through slag formation, and then performs hydrometallurgical refining to obtain platinum group metal products. Commonly used pyrometallurgical enrichment processes are base metal trapping methods, which can be divided into copper trapping, iron trapping, bismuth trapping, etc., depending on the trapping agent. Iron capture methods mainly include plasma melting and electric arc furnace melting. Plasma melting, at 2000°C, enriches platinum group metals into Fe-PGM alloys; however, at high temperatures, some silicon is reduced and dissolved into the alloy, forming a highly inert, corrosion-resistant, and refractory high-silicon iron alloy (Fe-PGM-Si). Electric arc furnace melting captures platinum, palladium, and rhodium using Fe or Fe3O4 at 1400°C. Using Bi2O3 as a capture agent, waste catalyst is reduced and melted at 1100°C, enriching Pt, Pd, and Rh into noble bismuth alloys. Multiple oxidation and blowing processes volatilize Bi, resulting in a total recovery rate of >99% for Pt, Pd, and Rh in the obtained noble bismuth alloy. The copper trapping method uses Cu or CuO as the trapping agent, adds CaO and SiO2 as slag-forming agents to remove the catalyst support, and adds fluxes such as Na2CO3 and borax (Na2B4O7) to lower the melting point of the slag phase. The copper is then reduced and smelted at 1350°C to produce crude copper enriched with platinum group metals.

[0003] In industry, copper or copper matte trapping methods are commonly used to treat waste three-way catalytic converters. Patent CN115418492A discloses a method for low-temperature smelting copper to trap platinum group metals (PGMs) in waste automotive exhaust catalysts. One or more of the following are used as trapping agents: copper powder, copper granules, waste copper cables, waste copper foil, copper oxide, cuprous oxide, copper carbonate, basic copper carbonate, and copper hydroxide. Salts containing sodium, potassium, and boron are added as co-solvents and mixed evenly with the waste catalyst. The mixture is then heated to 400–700°C for pre-activation, followed by a smelting and trapping process at 1000–1100°C to obtain precious copper containing PGMs. CN 104178634A discloses a method for efficiently and cleanly recovering PGMs from spent catalysts. Using copper oxide, copper carbonate, and copper hydroxide as collectors, and adding lime, quartz sand, and borax as slagging agents and fluxes, smelting is carried out at 1200–1400℃. During the smelting process, oxygen-enriched air with an oxygen concentration of 20-99% is injected to obtain Cu-PGMs. PGMs are then leached from the platinum group metal-enriched copper alloy using aqua regia + hydrochloric acid + oxidant. This patent provides a method for industrial-scale platinum group metal recovery. Because the high-alumina magnesium slag produced by smelting spent ternary catalysts has a high melting point, a large amount of slagging agent and fluxes containing sodium, potassium, and boron are needed to lower the system's melting point. 2+ Na + The slag is highly alkaline and corrosive to acidic smelting furnace linings. Smelting waste containing fluorine or boron requires careful handling. The crude copper ingots obtained from smelting are generally separated from platinum group metals using wet leaching or electrolytic refining. Wet leaching is inefficient and requires large amounts of solvents containing strong acids and bases, which is detrimental to environmental protection. When multiple solid wastes are co-smelted, the resulting crude copper ingots often contain impurities such as Fe, Pb, and Zn, which can affect the electrolytic refining process. Summary of the Invention

[0004] To overcome the above technical problems, the present invention aims to provide a method for the directional capture of platinum group metals through the reduction smelting of spent ternary catalysts (SAC) and spent circuit boards (WPCB). This method involves the co-smelting of SAC and WPCB, utilizing their own components to create slag and remove most impurities, thereby enriching the platinum group metals and avoiding the presence of sodium. + Boron-containing fluxing agents are added and the amount of fluxing agents and slagging agents added during the smelting process is reduced. After the copper liquid enriched with platinum group metals is discharged, pyrometallurgical refining is used to remove iron and lead from the crude copper liquid, thus avoiding the influence of impurity metal elements on the electrolytic refining process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for the directional capture of platinum group metals through reduction smelting of waste ternary catalysts and waste circuit boards includes the following steps; Step 1): The waste circuit board is pyrolyzed at low temperature to obtain carbon-rich black copper. The waste three-way catalyst with the steel shell removed is crushed to obtain waste three-way catalyst powder raw material. Step 2): The carbon-rich black copper obtained after pretreatment of waste circuit boards is mixed evenly with waste ternary catalyst powder in a certain proportion. The mass fraction of carbon-rich black copper is 50-80% of the total mass of the two materials. In order to obtain low-viscosity slag with <1 Pa·s and few solid inclusions under high temperature equilibrium, a slagging agent is added to adjust the composition of the smelting mixture into the furnace to the mass fraction of each component as follows: CaO = 4.00-6.00%, MgO = 3.00-9.00%, Al2O3 = 10.00-17%, and iron-silicon ratio Fe / SiO2 = 0.50-0.93. In addition, 10-25% of waste copper is added to make the copper content in the total material entering the furnace 25-30%. The mixture is sent to the smelting furnace for reduction smelting. Step 3): During the reduction smelting process, fuel and oxygen-enriched air are injected into the smelting furnace. The temperature of the melt inside the furnace rises to 1300-1400°C. A reducing agent is added to the melt inside the furnace, and the oxygen partial pressure inside the smelting furnace is controlled to pO2=10. 9 -10 8 atm, which means the oxygen volume fraction in the flue gas inside the smelting furnace is 10. 7 -10 6 %, smelt for 1–3 hours to obtain crude copper liquid; Step 4): The crude copper liquid is discharged from the copper outlet of the smelting furnace to the anode furnace for pyrometallurgical refining. 0.20% to 0.40% of silicon dioxide by mass of the crude copper liquid is added, and air is blown into the anode furnace by a spray gun to oxidize the iron impurity element in the crude copper liquid to form slag. Then the iron silicate slag layer floating on the surface of the crude copper liquid is scraped off to obtain copper liquid. Step 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace, and the molten copper is cast into a copper anode plate rich in platinum group metals; Step 6): The copper anode plate rich in platinum group metals is electrolytically refined to produce high-purity cathode copper. The rare and precious metals in the copper anode plate are precipitated at the bottom of the electrolytic cell to form electrolytic anode mud. The platinum group metals are then recovered from the electrolytic anode mud in a wet stepwise manner.

[0006] In step 1), the waste circuit board pretreatment process includes: Waste circuit boards are sheared and crushed into particles of 1–5 cm in size, and then pyrolyzed at 270–600°C in an oxygen-free atmosphere. This pyrolysis decomposes the organic resin in the waste circuit boards into flue gas, pyrolytic carbon, metals from the waste circuit boards, and glass fibers. The pyrolytic carbon, metals from the waste circuit boards, and glass fibers constitute carbon-rich black copper, of which carbon content accounts for 15–20% of the total mass of the carbon-rich black copper, metal accounts for 35–40% of the total mass of the carbon-rich black copper, and the remainder is glass fiber. This carbon-rich black copper is then crushed to 1–3 mm and used as a raw material for reduction smelting. The waste ternary catalyst with its steel shell removed was crushed to below 200µm.

[0007] In step 2), carbon-rich black copper scrap and waste ternary catalyst powder are mixed evenly in proportion, wherein the mass fraction of waste circuit boards is 50-80% of the total mass of the two materials; depending on the composition of the material fed into the furnace, the slag-forming agent is one or more of CaO, Al2O3, FeOx, and SiO2 (the purpose is to adjust the total composition of the material fed into the furnace to the target slag range).

[0008] In step 3), the fuel used in the reduction smelting process includes one or more of coke, water gas, natural gas, and heavy oil. The carbon content of the materials fed into the furnace—carbon-rich black copper, waste ternary catalyst powder, slagging agent, fuel, and reducing agent—is 10–16% of the total mass. If the carbon content is higher than this range, waste ternary catalyst cold feed needs to be added to the smelting furnace to maintain a stable smelting temperature. The mass ratio of the fuel to the volume of oxygen in the oxygen-enriched air is 1:1500–1900 t / Nm³. 3 .

[0009] In step 3), the reducing agent is one or more of coke, charcoal, natural gas, and water gas. The ratio of the reducing agent mass to the total mass of carbon-rich black copper and waste ternary catalyst is 1–2:20, and the oxygen partial pressure in the smelting furnace is pO2=10. 9 -10 8 atm, which means the oxygen volume fraction in the flue gas inside the smelting furnace is 10. 7 -10 6 %.

[0010] In step 3), the crude copper liquid rich in precious metals obtained from reduction smelting is discharged to the anode refining furnace when the copper mass fraction is ≥95%, the iron mass fraction is ≤0.3%, and the lead mass fraction is ≤6%.

[0011] In step 4), the mixture is stirred at 1150–1250°C for 0.5–2 h, allowed to stand for 0.5–1 h, and then the iron silicate slag layer floating on the surface of the crude copper liquid is scraped off to obtain the copper liquid.

[0012] In step 5), under a vacuum of 5–15 Pa, pre-lead removal is performed at 1180 °C for 30 min, followed by deep lead removal at 1220–1240 °C for 60–90 min.

[0013] The beneficial effects of this invention are: 1. FeO contained in the glass fiber of waste printed circuit boards xCaO, as a flux, combines with Al2O3, MgO, and CaO in the waste cordierite catalyst support to form a silicon-oxygen tetrahedron framework composed of Ca. 2+ Mg 2+ and Fe 2+ Low-melting-point iron silicate slag, stabilized by both covalent and ionic bonds, enables the synergistic treatment of two types of waste at a relatively low temperature of 1300°C.

[0014] 2. In the method steps of the present invention, no sodium or boron flux is added to reduce corrosion of the furnace lining, extend the service life of the equipment, and reduce maintenance costs and additional boron slag treatment costs.

[0015] 3. This invention screens out a range of low-viscosity slag components with a viscosity of less than 1 Pa·s from high-magnesium aluminum slag systems.

[0016] 4. This invention provides a three-stage impurity removal process for the synergistic treatment of waste catalysts and waste circuit boards, avoiding the influence of iron and lead on the copper electrolytic refining process.

[0017] 5. This invention controls the oxygen-to-material ratio during the smelting process to ensure that the oxygen fuel in the furnace is fully combusted for heat supply and to maintain a reducing atmosphere in the furnace, thus avoiding copper loss caused by excess oxygen reacting with the materials. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings.

[0020] Example 1: A method for enriching precious metals by co-melting waste ternary catalysts and waste circuit boards includes: 1): The carbon-rich black copper obtained from the pyrolysis of waste circuit boards is crushed to 1–3 mm, and the dismantled waste ternary catalyst is crushed and ground to below 200 µm.

[0021] 2): Mix the pretreated waste circuit boards and waste ternary catalyst powder raw materials evenly in a certain proportion. The mass fraction of carbon-rich black copper is 70% of the total mass of the two materials. Add slag-forming agent to adjust the slag composition so that the mass fraction of each component in the mixture is Fe / SiO2=0.75, Al2O3=13.14%, MgO=8.00%, CaO=6.00%. Add 13% waste copper and send the mixture to the smelting furnace for reduction smelting.

[0022] 3): Heavy oil is injected into the furnace as fuel, at a rate of 255.8 Nm. 3With a blowing rate of / (h·t), 40% oxygen-enriched air is introduced, and the temperature is raised to 1300℃ and held for 3 hours. At this time, the slag viscosity is 0.518 Pa·s.

[0023] 4): After smelting, drain the molten copper from the tap into the anode furnace, add 0.3% silicon dioxide by weight of the molten copper, and blow in air. Stir at 1150℃ for 2 hours, let stand for 1 hour, and then scrape off the layer of iron silicate slag floating on the surface of the molten copper.

[0024] 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace. Under a vacuum of 6 Pa, it is pre-de-leaded at 1180°C for 30 min and deep de-leaded at 1220°C for 60 min. Finally, the molten copper is cast into a copper anode plate rich in platinum group metals.

[0025] 6) The copper anode plate rich in platinum group metals is electrolytically refined into high-purity cathode copper, and the platinum group metals are recovered from the electrolytic anode mud in a wet stepwise manner.

[0026] Example 2: A method for enriching precious metals by co-melting waste ternary catalysts and waste circuit boards includes: 1): The carbon-rich black copper obtained from the pyrolysis of waste circuit boards is crushed to 1–3 mm, and the dismantled waste ternary catalyst is crushed and ground to below 200 µm.

[0027] 2): Mix the pretreated waste circuit boards and waste ternary catalyst powder raw materials evenly in a certain proportion. The mass fraction of carbon-rich black copper is 60% of the total mass of the two materials. Add slag-forming agent to adjust the slag composition so that the mass fraction of each component in the mixture is Fe / SiO2=0.75, Al2O3=11.49%, MgO=8.00%, CaO=5.50%. Add 15% waste copper and send the mixture to the smelting furnace for reduction smelting.

[0028] 3): Pulverized coal is injected into the furnace as fuel, at a rate of 219.0 Nm³. 3 With a blowing rate of / (h·t), 40% oxygen-enriched air is introduced, and the temperature is raised to 1300℃ and held for 3 hours. At this time, the slag viscosity is 0.474 Pa·s.

[0029] 4): After smelting, drain the molten copper from the tap into the anode furnace, add 0.25% silicon dioxide by weight of the molten copper, blow in air, stir at 1200℃ for 1 h, let stand for 0.5 h, and then scrape off the layer of iron silicate slag floating on the surface of the molten copper.

[0030] 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace. Under a vacuum of 7 Pa, it is pre-de-leaded at 1180°C for 30 min and deep de-leaded at 1230°C for 70 min. Finally, the molten copper is cast into an anode plate.

[0031] 6): The copper anode plate rich in platinum group metals is electrolytically refined into high-purity cathode copper, and the platinum group metals are recovered from the electrolytic anode mud in a wet stepwise manner.

[0032] Example 3: A method for enriching precious metals by co-melting waste ternary catalysts and waste circuit boards includes: 1): The carbon-rich black copper obtained from the pyrolysis of waste circuit boards is crushed to 1–3 mm, and the dismantled waste ternary catalyst is crushed and ground to below 200 µm.

[0033] 2): Mix the pretreated waste circuit boards and waste ternary catalyst powder raw materials evenly in a certain proportion. The mass fraction of carbon-rich black copper is 50% of the total mass of the two materials. Add slag-forming agent to adjust the slag composition so that the mass fraction of each component in the mixture is Fe / SiO2=0.82, Al2O3=10.72%, MgO=8.50%, CaO=5.00%. Add 17% waste copper and send the mixture to the smelting furnace for reduction smelting.

[0034] 3): Coke powder is injected into the furnace as fuel, at a rate of 121.6 Nm. 3 With a blowing rate of / (h·t), 60% oxygen-enriched air is introduced, and the temperature is raised to 1300℃ and held for 3 hours. At this time, the slag viscosity is 0.372 Pa·s.

[0035] 4): After smelting, drain the molten copper from the tap into the anode furnace, add 0.2% silicon dioxide by weight of the molten copper, and blow in air. Stir at 1150℃ for 2 hours, let stand for 1 hour, and then scrape off the layer of iron silicate slag floating on the surface of the molten copper.

[0036] 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace. Under a vacuum of 6 Pa, it is pre-de-leaded at 1180°C for 30 min and deep de-leaded at 1240°C for 60 min. Finally, the molten copper is cast into an anode plate.

[0037] 6): The copper anode plate rich in platinum group metals is electrolytically refined into high-purity cathode copper, and the platinum group metals are recovered from the electrolytic anode mud in a wet stepwise manner.

[0038] Example 4: A method for enriching precious metals by co-melting waste ternary catalysts and waste circuit boards includes: 1): The carbon-rich black copper obtained from the pyrolysis of waste circuit boards is crushed to 1–3 mm, and the dismantled waste ternary catalyst is crushed and ground to below 200 µm.

[0039] 2): Mix the pretreated waste circuit boards and waste ternary catalyst powder raw materials evenly in a certain proportion. The mass fraction of carbon-rich black copper is 70% of the total mass of the two materials. Add slag-forming agent to adjust the slag composition so that the mass fraction of each component in the mixture is Fe / SiO2=0.60, Al2O3=11.27%, MgO=8.50%, CaO=5.00%. Add 14% waste copper and send the mixture to the smelting furnace for reduction smelting.

[0040] 3): Heavy oil is injected into the furnace as fuel, at a rate of 170.5 Nm. 3 With a blowing rate of / (h·t), 60% oxygen-enriched air is introduced, and the temperature is raised to 1300℃ and held for 3 hours. At this time, the slag viscosity is 0.868 Pa·s.

[0041] 4): After smelting, drain the molten copper from the tap into the anode furnace, add 0.3% silicon dioxide by weight of the molten copper, and blow in air. Stir at 1150℃ for 2 hours, let stand for 1 hour, and then scrape off the layer of iron silicate slag floating on the surface of the molten copper.

[0042] 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace. Under a vacuum of 6 Pa, it is pre-de-leaded at 1180°C for 30 min and deep de-leaded at 1240°C for 70 min. Finally, the molten copper is cast into an anode plate.

[0043] 6): The anode plates are sent to the electrolysis workshop, the cathode copper is sold externally, and platinum group metals are recovered from the anode mud by wet process.

[0044] Example 5: A method for enriching precious metals by co-melting waste ternary catalysts and waste circuit boards includes: 1): The carbon-rich black copper obtained from the pyrolysis of waste circuit boards is crushed to 1–3 mm, and the dismantled waste ternary catalyst is crushed and ground to below 200 µm; 2) The pretreated waste circuit boards and waste ternary catalyst powder are mixed evenly in a certain proportion, with the mass fraction of carbon-rich black copper being 60% of the total mass of the two materials. A slag-forming agent is added to adjust the slag composition so that the mass fractions of each component in the mixture are Fe / SiO2=0.71, Al2O3=10.35%, MgO=9.00%, and CaO=4.50%. 16% waste copper is added, and the mixture is sent to a smelting furnace for reduction smelting. 3): Pulverized coal is injected into the furnace as fuel, at a rate of 219.0 Nm³. 3 With a blowing rate of / (h·t), 40% oxygen-enriched air is introduced, and the temperature is raised to 1300℃ and held for 3 hours. At this time, the slag viscosity is 0.521 Pa·s.

[0045] 4): After smelting, drain the molten copper from the tap into the anode furnace, add 0.28% silicon dioxide by weight of the molten copper, and blow in air. Stir at 1150℃ for 2 hours, let stand for 1 hour, and then scrape off the layer of iron silicate slag floating on the surface of the molten copper.

[0046] 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace. Under a vacuum of 6 Pa, it is pre-de-leaded at 1180°C for 30 min and deep de-leaded at 1220°C for 60 min. Finally, the molten copper is cast into an anode plate.

[0047] 6) The copper anode plate rich in platinum group metals is electrolytically refined into high-purity cathode copper, and the platinum group metals are recovered from the electrolytic anode mud in a wet stepwise manner.

[0048] Table 1. Composition of waste circuit boards (carbon-rich black copper) (wt%) Components Cu Fe Al Pb Zn Sn Al2O3 CaO MgO SiO2 C Content wt.% 14.57 13.96 5.27 2.58 1.69 2.19 2.28 4.08 1.11 11.52 17.91 Table 2 Main Components of Waste Three-Way Catalysts Components Al2O3 SiO2 ZrO2 MgO CeO2 MnO Fe2O3 NiO BaO Sample 1 content wt.% 44.64 23.02 7.53 6.53 14.67 \ \ \ 3.87 Content of sample 2 in wt.% 49.9 21.75 7.49 6.16 8.71 0.72 \ 0.83 4.75 Sample 3 content wt.% 43.83 30.31 10.7 7.19 4.51 2.48 0.98 \ \ This invention involves mixing waste circuit boards (after pyrolysis to remove organic resin), waste ternary catalysts, and slagging agents in a specific ratio, and then performing reduction smelting in a pyrometallurgical furnace. The resulting mixture is smelted at 1300°C and held for 3 hours. Rich in precious metals, crude copper is discharged from the copper tap. After pyrometallurgical refining to remove iron and vacuum induction furnace lead, it is cast into anode plates. High-purity cathode copper is obtained through electrolytic refining of the copper anode plates, and platinum group metals are recovered stepwise from the copper anode sludge using a wet process. This invention identifies a low-viscosity slag composition control range for high-magnesium-aluminum slag, enabling the synergistic recovery of two hazardous wastes through low-temperature smelting at 1300°C. This eliminates the need for sodium-boron fluxes, reduces the corrosion of the furnace lining by alkaline additives, and extends equipment lifespan.

Claims

1. A method for the directional capture of platinum group metals through reduction smelting of waste ternary catalysts and waste circuit boards, characterized in that, Includes the following steps; Step 1): The waste circuit board is pyrolyzed at low temperature to obtain carbon-rich black copper. The waste three-way catalyst with the steel shell removed is crushed to obtain waste three-way catalyst powder raw material. Step 2): Mix the carbon-rich black copper obtained after pretreatment of waste circuit boards with waste ternary catalyst powder raw materials in a certain proportion. The mass fraction of carbon-rich black copper is 50-80% of the total mass of the two materials. Add slag-forming agent and adjust the composition of the mixture entering the furnace to the mass fraction of each component as follows: CaO = 4.00-6.00%, MgO = 3.00-9.00%, Al2O3 = 10.00-17%, and Fe / SiO2 ratio = 0.50-0.

93. In addition, add 10-25% of waste copper to make the copper content in the total material entering the furnace 25-30%. The mixture is then sent to the smelting furnace for reduction smelting. Step 3): During the reduction smelting process, fuel and oxygen-enriched air are injected into the smelting furnace. The temperature of the melt inside the furnace rises to 1300-1400°C. A reducing agent is added to the melt inside the furnace, and the oxygen partial pressure inside the smelting furnace is controlled to pO2=10. 9 -10 8 atm, which means the oxygen volume fraction in the flue gas inside the smelting furnace is 10. 7 -10 6 %, smelt for 1–3 hours to obtain crude copper liquid; Step 4): The crude copper liquid is discharged from the copper outlet of the smelting furnace to the anode furnace for pyrometallurgical refining. 0.20% to 0.40% of silicon dioxide by mass of the crude copper liquid is added, and air is blown into the anode furnace by a spray gun to oxidize the iron impurity element in the crude copper liquid to form slag. Then the iron silicate slag layer floating on the surface of the crude copper liquid is scraped off to obtain copper liquid. Step 5): The molten copper is discharged from the copper outlet of the anode refining furnace to the vacuum induction furnace, and the molten copper is cast into a copper anode plate rich in platinum group metals; Step 6): The copper anode plate rich in platinum group metals is electrolytically refined to produce high-purity cathode copper. The rare and precious metals in the copper anode plate are precipitated at the bottom of the electrolytic cell to form electrolytic anode mud. The platinum group metals are then recovered from the electrolytic anode mud in a wet stepwise manner.

2. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 1), the waste circuit board pretreatment process includes: Waste circuit boards are sheared and crushed into particles of 1–5 cm in size, and then pyrolyzed at 270–600°C in an oxygen-free atmosphere. This pyrolysis decomposes the organic resin in the waste circuit boards into flue gas, pyrolytic carbon, metals from the waste circuit boards, and glass fibers. The pyrolytic carbon, metals from the waste circuit boards, and glass fibers constitute carbon-rich black copper, of which carbon content accounts for 15–20% of the total mass of the carbon-rich black copper, metal accounts for 35–40% of the total mass of the carbon-rich black copper, and the remainder is glass fiber. This carbon-rich black copper is then crushed to 1–3 mm and used as a raw material for reduction smelting. The waste ternary catalyst with its steel shell removed was crushed to below 200µm.

3. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 2), carbon-rich black copper scrap and waste ternary catalyst powder are mixed evenly in a certain proportion, wherein the mass fraction of waste circuit boards is 50-80% of the total mass of the two materials. Depending on the composition of the material fed into the furnace, the slagging agent is specifically one or more of CaO, Al2O3, FeOx, and SiO2.

4. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 3), the fuel used in the reduction smelting process includes one or more of coke, water gas, natural gas, and heavy oil. The carbon content of the materials fed into the furnace, including carbon-rich black copper, waste three-way catalyst powder, slagging agent, fuel, and reducing agent, is 10–16% of the total mass. The mass ratio of the fuel to the volume of oxygen in the oxygen-enriched air is 1:1500–1900 t / Nm³. 3 .

5. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 3), the reducing agent is one or more of coke, charcoal, natural gas, and water gas. The ratio of the reducing agent mass to the total mass of carbon-rich black copper and waste ternary catalyst is 1–2:20, and the oxygen partial pressure in the smelting furnace is pO2=10. 9 -10 8 atm, which means the oxygen volume fraction in the flue gas inside the smelting furnace is 10. 7 -10 6 %.

6. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 3), the crude copper liquid rich in precious metals obtained from reduction smelting is discharged to the anode refining furnace when the copper mass fraction is ≥95%, the iron mass fraction is ≤0.3%, and the lead mass fraction is ≤6%.

7. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 4), the mixture is stirred at 1150–1250°C for 0.5–2 h, allowed to stand for 0.5–1 h, and then the iron silicate slag layer floating on the surface of the crude copper liquid is scraped off to obtain the copper liquid.

8. The method for directional capture of platinum group metals by reduction smelting of waste ternary catalysts and waste circuit boards according to claim 1, characterized in that, In step 5), under a vacuum of 5–15 Pa, pre-lead removal is performed at 1180 °C for 30 min, followed by deep lead removal at 1220–1240 °C for 60–90 min.

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