A method for recovering valuable elements by co-reduction smelting of NdFeB waste and electronic waste.

Abstract

This invention provides a method for recovering valuable elements from NdFeB waste through co-reduction smelting of electronic waste. The method involves mixing powdered NdFeB waste and fine-grained electronic waste with a slagging agent and a solid reducing agent, and then using a top-blown smelting furnace to reduce and smelt the mixture. By controlling the conditions of the reduction process, the oxides of copper and iron in the mixture are reduced to metallic copper and metallic iron. These two metals then aggregate with rare and precious metals such as gold and silver from the electronic waste to form a copper-iron precious metal alloy. Rare earth oxides are not reduced and remain in the slag layer. The copper-iron precious metal alloy particles are denser than the rare earth slag and sink rapidly to the bottom of the furnace. After settling and stratification, the copper-iron precious metal alloy melt and the rare earth slag are discharged separately from the metal outlet and slag outlet, respectively. This method achieves the simultaneous recovery of rare earth elements from NdFeB waste and copper, gold, and silver from electronic waste. The process is short, energy-efficient, and offers significant economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of neodymium iron boron and electronic waste recycling technology, and particularly to a method for recovering valuable elements by synergistic reduction smelting of neodymium iron boron waste and electronic waste. Background Technology

[0002] Rare earth elements are important resources, often referred to as "industrial MSG." Neodymium iron boron (NdFeB) materials, in particular, are widely used in industries such as motors, defense, aerospace, and wind power due to their excellent performance. However, due to process limitations and equipment lifespan, a large amount of NdFeB waste is generated. This waste contains significant amounts of rare earth elements and iron, representing a substantial potential for utilization.

[0003] With the rapid development of technology and the accelerated pace of electronic product updates, the amount of waste electronic products is increasing day by day. The core component in electronic waste is the circuit board. Waste circuit boards not only contain valuable metals such as copper, gold, and silver, but also harmful heavy metal elements. They are listed in the National Hazardous Waste List (No. 900-045-49). If they are not utilized, they will not only waste valuable metals, but also pollute the environment.

[0004] Currently, most methods for treating NdFeB waste involve pyrometallurgical and hydrometallurgical processes to separate rare earth elements and iron. However, these methods do not fully utilize the separated iron, have high energy consumption per furnace, and generate large amounts of wastewater. Meanwhile, most electronic waste treatment processes employ pyrometallurgical methods, including closed blast furnace smelting, Osmette furnace smelting, flash furnace smelting, Kaldor furnace smelting, side-blown furnace smelting, and bottom-blown furnace smelting. Due to the inherent limitations of these smelting processes, the comprehensive recovery of valuable metals from electronic waste using these methods still suffers from low recovery rates, long processes, high energy consumption, low raw material adaptability, and severe secondary pollution.

[0005] In view of this, it is necessary to design an improved method for recovering rare earth and valuable metals from NdFeB waste and electronic waste in order to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a method for recovering valuable elements by smelting neodymium iron boron waste in conjunction with electronic waste.

[0007] To achieve the above-mentioned objectives, this invention provides a method for recovering valuable elements through the reduction and smelting of neodymium iron boron waste and electronic waste, comprising the following steps:

[0008] S1. Dismantle, sort, crush, and ball mill the NdFeB waste and electronic waste. Mix the pretreated powdered NdFeB waste and fine granular electronic waste with slagging agent and solid reducing agent. Use the feeding system to add the mixture to the top blown smelting furnace through the top feeding port.

[0009] S2. Using a smelting lance, reducing gas and process air are introduced into the smelting furnace to control the furnace temperature at 1300℃~1600℃. The mixed material floats in a highly dispersed state from the top of the furnace to the bottom. During this process, the reducing atmosphere is controlled to keep the oxygen partial pressure of the smelting system in the furnace below 10. -20 In the process of ATM (Atmospheric Mixture), as the material falls, most of the copper and iron oxides are reduced to metallic copper and metallic iron. These form copper-iron precious metal alloys with gold and silver in electronic waste. However, rare earth oxides are not reduced and form rare earth slag phases with slag-forming agents. When the high-temperature melt obtained from reduction falls to the bottom of the smelting furnace, it is rapidly drawn into the molten pool under the strong stirring of the gas flow from the smelting lance outlet. It is thoroughly mixed with the solid reducing agent inside the molten pool. By controlling the amount of solid reducing agent and the ratio of reducing gas to process air, bubbles are generated inside the reduced slag, further enhancing the kinetics of the reduction reaction. This allows a small portion of the unreduced copper and iron oxides to be further reduced to metallic copper and metallic iron, and precious metals such as gold and silver in the slag are captured to form copper-iron precious metal alloys.

[0010] S3. After the reduction process is completed, stop adding materials and reducing agents, remove the smelting torch from the molten pool for heat preservation, allow the slag to stand and separate, and discharge the copper-iron precious metal alloy melt and rare earth slag from the metal outlet and slag outlet respectively.

[0011] Furthermore, the electronic waste refers to discarded electronic or electrical equipment and its components, including products that are discarded due to technological obsolescence, damage, or reaching the end of their service life, such as televisions, refrigerators, computers, and mobile phones.

[0012] Furthermore, the particle size of the neodymium iron boron waste is 50 mesh or less, and the particle size of the electronic waste is 10 mm to 50 mm.

[0013] Furthermore, the slag-forming agent is at least one of SiO2 and CaO, and its particle size is 1 mm to 10 mm.

[0014] Furthermore, the mass fraction of iron w(Fe) in the mixture is 15%–30%, the mass fraction of silicon dioxide w(SiO2) is 25%–40%, and the mass fraction of calcium oxide w(CaO) is 15%–25%.

[0015] Furthermore, the mixture is added at a rate of 2t / h to 6t / h through the top feed port of the furnace.

[0016] Furthermore, the NdFeB waste has a high iron content, and when it is co-smelted with electronic waste, it can supplement the electronic waste with iron elements to form slag, without the need to add additional iron slag-forming agents.

[0017] Furthermore, the reducing gas and solid reducing agent can be used as fuel.

[0018] Furthermore, the reducing gas is one or more of carbon monoxide, hydrogen, natural gas, and shale gas, preferably natural gas.

[0019] Furthermore, the solid reducing agent is at least one of coke and coal.

[0020] Furthermore, the reducing atmosphere has a ratio of reducing gas to process air volume of 1:10 to 1:15, and the residual oxygen concentration in the flue gas is 1% to 4%.

[0021] Furthermore, the reduced smelting flue gas passes through a secondary combustion system, a waste heat recovery system, a rapid cooling system, an activated carbon injection system, a dust removal system, and a desulfurization system before being discharged in compliance with emission standards.

[0022] Furthermore, the bubbles are generated during a strong reduction reaction when the reducing gas cannot escape in time from the molten slag with high viscosity.

[0023] Furthermore, the slag settling and stratification process allows alloy particles to settle rapidly within the bubble layer of the slag, significantly shortening the settling time.

[0024] Furthermore, the organic matter inherent in the electronic waste itself has a high calorific value, which can provide heat for the co-melting of NdFeB waste during combustion, greatly reducing energy consumption.

[0025] Furthermore, the morphology of the reduction residue is observed and analyzed by using a probe to determine the reduction endpoint.

[0026] The present invention provides a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste, which has the following features and advantages:

[0027] (1) This method involves mixing powdered NdFeB waste and fine-particle electronic waste with slagging agents and solid reducing agents. The mixture is fed into the furnace through the top charging port. The fine-particle material is highly dispersed during its descent, making full contact with the high-temperature reducing gas in the furnace and rapidly undergoing a reduction reaction to form molten metal that falls into the molten pool at the bottom of the furnace. Furthermore, the NdFeB waste has a high iron content, which can supplement the electronic waste with iron for slagging during co-smelting, eliminating the need for additional iron-based slagging agents. The organic matter inherent in the electronic waste has a high calorific value, which can provide some heat for the co-smelting of NdFeB waste during combustion, significantly reducing energy consumption.

[0028] (2) Unreduced iron oxides and copper oxides fall into the molten pool and are thoroughly mixed and contacted with the solid reducing agent in the molten pool under the agitation of the gas flow at the outlet of the smelting lance, creating good reaction kinetic conditions, so that the iron oxides and copper oxides in the mixed smelting slag are quickly and completely reduced to metallic iron and metallic copper. The two aggregate with rare and precious metals such as gold and silver in electronic waste to form copper-iron precious metal alloys, while rare earth oxides are not reduced and continue to remain in the slag layer.

[0029] (3) Copper-iron precious metal alloy particles have a higher density than rare earth slag. They can quickly sink into the metal layer in the molten slag foam layer. After static stratification, the copper-iron precious metal alloy melt and rare earth slag are discharged from the metal port and slag port respectively, without the need for forced separation by ultra-gravity slag-gold fusion separation and magnetic separation.

[0030] In summary, this invention enables the simultaneous recovery of rare earth elements from NdFeB waste and copper, gold, and silver from electronic waste, truly achieving multi-recovery from a single furnace. It features a short process, low energy consumption, and significant economic and environmental benefits, making it highly valuable for widespread application. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic flowchart of a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste, as proposed in this invention.

[0033] Figure 2 This is a schematic diagram of the top-blown smelting furnace used in the embodiment when recycling rare earth elements, copper, gold, and silver from neodymium iron boron waste and electronic waste using the recycling method proposed in this invention.

[0034] The labels in the attached diagram are: 1. Top-blown smelting furnace; 2. Smelting lance; 3. Probe rod; 4. Feed port; 5. Slag discharge port; 6. Metal port. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0037] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] This invention provides a method for recovering valuable elements from neodymium iron boron waste through co-reduction smelting of electronic waste, such as... Figure 1 As shown, it includes the following steps:

[0039] S1. Dismantle, sort, crush, and ball mill the NdFeB waste and electronic waste. Mix the pretreated powdered NdFeB waste and fine granular electronic waste with slagging agent and solid reducing agent. Use the feeding system to add the mixture to the top blown smelting furnace through the top feeding port.

[0040] S2. Using a smelting torch, reducing gas and process air are introduced into the smelting furnace to control the temperature inside the furnace at 1300℃~1600℃. The mixed materials are in a highly dispersed floating state and fall from the top of the furnace to the bottom. During this process, the reducing atmosphere is controlled so that the oxygen partial pressure of the smelting system inside the furnace is lower than 10atm~20atm. During the falling process, most of the copper and iron oxides are reduced to metallic copper and metallic iron. The two form copper-iron precious metal alloys with gold and silver in electronic waste, while rare earth oxides are not reduced and form rare earth slag phases with slag-forming agents. When the high-temperature melt obtained from reduction in the smelting furnace falls to the bottom of the furnace, it is rapidly drawn into the molten pool under the strong stirring of the gas flow from the smelting lance outlet. It mixes thoroughly and evenly with the solid reducing agent inside the molten pool. Furthermore, by controlling the amount of solid reducing agent and the ratio of reducing gas to process air, bubbles are generated inside the reduced slag, which further enhances the kinetic conditions of the reduction reaction. This allows a small portion of the unreduced copper and iron oxides to be further reduced to metallic copper and metallic iron, and precious metals such as gold and silver are captured in the slag to form a copper-iron precious metal alloy.

[0041] S3. After the reduction process is completed, stop adding materials and reducing agents, remove the smelting torch from the molten pool for heat preservation, allow the slag to stand and separate, and discharge the copper-iron precious metal alloy melt and rare earth slag from the metal outlet and slag outlet respectively.

[0042] The above-mentioned recycling process is completed using a top-blown smelting furnace 1, the structural diagram of which is shown below. Figure 2As shown, the top-blown smelting furnace 1 includes a furnace body. The top of the furnace body has a flue outlet and a feeding port 4, while the bottom of the furnace body has a slag discharge port 5 and a metal outlet 6. Inside the furnace body, there is a smelting lance 2 that penetrates the inner wall of the furnace body and extends to the lower part of the furnace body, and a probe 3. The smelting lance 2 is used to introduce reducing gas and process air into the furnace. The probe 3 is used to measure the liquid level in the furnace and the composition and morphology of the reducing slag at the upper part of the probe 3, analyzing and determining the reduction endpoint and reduction time. In other embodiments, other smelting furnaces that can achieve the above objectives can also be selected as needed.

[0043] In one embodiment of the present invention, in step S1, the electronic waste refers to discarded electronic or electrical equipment and its components, including products that are discarded due to technological obsolescence, damage, or reaching the end of their service life, such as televisions, refrigerators, computers, and mobile phones.

[0044] In one embodiment of the present invention, in step S1, the materials entering the furnace need to be pre-treated so that the particle size of the NdFeB waste is 50 mesh or less and the particle size of the electronic waste is 10 mm to 50 mm.

[0045] In one embodiment of the present invention, in step S1, the NdFeB waste has a high iron content, and when it is smelted in conjunction with electronic waste, it can supplement the electronic waste with iron elements to form slag, without the need to add additional iron slag-forming agents.

[0046] In one embodiment of the present invention, in step S1, the slag-forming agent is at least one of SiO2 and CaO, and its particle size is 1 mm to 10 mm.

[0047] In one embodiment of the present invention, in step S1, the mass fraction of iron w(Fe) in the mixture is 15% to 30%, the mass fraction of silicon dioxide w(SiO2) is 25% to 40%, and the mass fraction of calcium oxide w(CaO) is 15% to 25%.

[0048] In one embodiment of the present invention, in step S1, the mixture is added from the top feed port of the furnace at a rate of 2t / h to 6t / h.

[0049] In one embodiment of the present invention, in step S1, the reducing gas and the solid reducing agent are both fuel and reducing agent.

[0050] In one embodiment of the present invention, in step S1, the reducing gas is one or more of carbon monoxide, hydrogen, natural gas, and shale gas, preferably natural gas.

[0051] In one embodiment of the present invention, in step S1, the solid reducing agent is at least one of coke and coal.

[0052] In one embodiment of the present invention, in step S1, the organic matter contained in the electronic waste itself has a high calorific value, which can provide heat for the co-melting of neodymium iron boron waste during combustion, thus greatly reducing energy consumption.

[0053] In one embodiment of the present invention, in step S2, the reducing atmosphere is a ratio of reducing gas to process air volume of 1:10 to 1:15, and the residual oxygen concentration in the flue gas is 1% to 4%.

[0054] In one embodiment of the present invention, in step S2, the reduced smelting flue gas passes through a flue gas secondary combustion system, a waste heat recovery system, a flue gas quenching system, an activated carbon injection system, a dust removal system, and a desulfurization system before being discharged in compliance with emission standards.

[0055] In one embodiment of the present invention, in step S2, the bubbles are generated because the reducing gas cannot escape in time from the molten slag with high viscosity during the strong reduction reaction process.

[0056] In one embodiment of the present invention, in step S3, the slag is allowed to settle into layers, and the alloy particles can quickly settle on the surface of the bubble layer of the slag, which greatly shortens the settling time.

[0057] In one embodiment of the present invention, in step S2, the morphology of the reduction residue is sampled, observed and analyzed using a probe to determine the reduction endpoint.

[0058] In the above technical solution, the characteristics of NdFeB waste (high iron content, low calorific value) and electronic waste (low iron content, high calorific value) are utilized. By mixing NdFeB waste, electronic waste, quartz, limestone (the main component of limestone is calcium carbonate (CaCO3), which decomposes into CaO at high temperatures in the furnace), and a solid reducing agent, the NdFeB waste can supplement the electronic waste with iron for slagging, eliminating the need for additional iron-based slagging agents. Meanwhile, the high calorific value of the electronic waste provides heat for the co-smelting of the NdFeB waste, significantly reducing energy consumption. When the mixture is added to the top-blown smelting furnace, the powdered material comes into full contact with the reducing gas in the furnace during its descent, creating favorable kinetic conditions for the reduction reaction and resulting in a rapid reduction reaction. Unreduced iron and copper oxides fall to the bottom of the furnace and are rapidly drawn into the molten pool by the gas flow from the smelting lance outlet. There, they react with the solid reducing agent inside the pool to form metallic iron and metallic copper, while simultaneously capturing rare and precious metals such as gold and silver from the electronic waste, forming a copper-iron precious metal alloy. Rare earth oxides remain unreduced in the slag layer. This process fully utilizes the high iron content of NdFeB waste and the high calorific value of electronic waste to recover copper, avoiding the need for additional iron supplementation during smelting due to the low iron content of electronic waste. By controlling the reduction conditions and utilizing the high viscosity of the high-silicon, high-calcium slag, a foam layer is easily formed in the molten slag during strong reduction smelting, increasing the specific surface area of ​​the slag and enhancing the kinetics of the gas-solid two-phase reduction reaction, thus facilitating the reduction reaction. Valuable metals such as gold and silver in the electronic waste aggregate into an alloy melt encased in the copper-iron alloy. This alloy melt, with a higher density than the rare earth slag, rapidly sinks into the bottom of the furnace within the foam layer, forming the copper-iron precious metal alloy. After the reduction process is completed, the addition of materials and reducing agents is stopped, the smelting lance is removed from the molten pool and kept warm, allowing the slag to settle and separate into layers. The copper-iron precious metal alloy melt and rare earth slag are discharged from the metal outlet and slag outlet, respectively.

[0059] The following specific embodiments further illustrate the method for recovering valuable elements from neodymium iron boron waste through co-reduction smelting of electronic waste proposed in this invention:

[0060] Example 1

[0061] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0062] Neodymium iron boron waste with a particle size of 50 mesh and electronic waste with a block size of 50 mm were mixed with quartz, limestone, and coke. The mass fraction of iron (w(Fe)) in the mixture was 25%, the mass fraction of silicon dioxide (w(SiO2)) was 31%, and the mass fraction of calcium oxide (w(CaO)) was 18%. The mixture was added to the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1385℃ and the residual oxygen concentration in the flue gas was 4%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 52.5% and an iron content of 45.8% and a rare earth slag with a neodymium content of 42.3% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 96.5%, and the total recovery rate of copper in the electronic waste was 97.7%.

[0063] Example 2

[0064] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0065] Neodymium iron boron waste with a particle size of 50 mesh and electronic waste with a block size of 40 mm were mixed with quartz, limestone, and coke. The mass fraction of iron (w(Fe)) in the mixture was 22%, the mass fraction of silicon dioxide (w(SiO2)) was 32%, and the mass fraction of calcium oxide (w(CaO)) was 19%. The mixture was added to the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1393℃ and the residual oxygen concentration in the flue gas was 3%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 52.9% and an iron content of 45.2% and a rare earth slag with a neodymium content of 42.5% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 96.7%, and the total recovery rate of copper in the electronic waste was 97.1%.

[0066] Example 3

[0067] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0068] Neodymium iron boron waste with a particle size of 100 mesh and electronic waste with a block size of 40 mm were mixed with quartz, limestone and coke. The mass fraction of iron w(Fe) in the mixture was 23%, the mass fraction of silicon dioxide w(SiO2) was 32%, and the mass fraction of calcium oxide w(CaO) was 21%. The mixture was added to the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1433℃ and the residual oxygen concentration of the flue gas was 3%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 53.3% and an iron content of 45.1% and a rare earth slag with a neodymium content of 42.8% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 96.9%, and the total recovery rate of copper in the electronic waste was 97.5%.

[0069] Example 4

[0070] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0071] Neodymium iron boron waste with a particle size of 100 mesh and electronic waste with a block size of 30 mm were mixed with quartz, limestone and coke. The mass fraction of iron w(Fe) in the mixture was 23%, the mass fraction of silicon dioxide w(SiO2) was 33%, and the mass fraction of calcium oxide w(CaO) was 21%. The mixture was added to the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1453℃ and the residual oxygen concentration of the flue gas was 2%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 53.5% and an iron content of 45.3% and a rare earth slag with a neodymium content of 43.3% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 97.7%, and the total recovery rate of copper in the electronic waste was 98.1%.

[0072] Example 5

[0073] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0074] Neodymium iron boron waste with a particle size of 100 mesh and electronic waste with a block size of 20 mm were mixed with quartz, limestone and coke. The mass fraction of iron w(Fe) in the mixture was 24%, the mass fraction of silicon dioxide w(SiO2) was 33%, and the mass fraction of calcium oxide w(CaO) was 22%. The mixture was added into the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1475℃ and the residual oxygen concentration of the flue gas was 2%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 53.3% and an iron content of 45.5% and a rare earth slag with a neodymium content of 43.7% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 98.4%, and the total recovery rate of copper in the electronic waste was 98.8%.

[0075] Example 6

[0076] This embodiment proposes a method for recovering valuable elements by co-reduction smelting of neodymium iron boron waste and electronic waste. The specific reduction and recovery method is as follows:

[0077] Neodymium iron boron waste with a particle size of 100 mesh and electronic waste with a block size of 10 mm were mixed with quartz, limestone, and coke. The mass fraction of iron (w(Fe)) in the mixture was 26%, the mass fraction of silicon dioxide (w(SiO2)) was 33%, and the mass fraction of calcium oxide (w(CaO)) was 22%. The mixture was added to the top-blown smelting furnace 1 through the feeding port 4. The furnace temperature was 1495℃ and the residual oxygen concentration in the flue gas was 1%. After smelting under these reducing conditions for 60 minutes, the mixture was allowed to settle for 15 minutes. A copper-iron precious metal alloy with a copper content of 53.3% and an iron content of 45.5% and a rare earth slag with a rare earth content of 43.9% were obtained from the metal port 6 and the slag discharge port 5, respectively. The total recovery rate of rare earth in the neodymium iron boron waste was 98.3%, and the total recovery rate of copper in the electronic waste was 98.9%.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for recovering valuable elements by co-reduction smelting of NdFeB waste and electronic waste, characterized in that, Includes the following steps: S1. Dismantle, sort, crush, and ball mill pre-treat neodymium iron boron waste and electronic waste. Mix the pre-treated powdered neodymium iron boron waste and fine granular electronic waste with slagging agent and solid reducing agent. Use the feeding system to add the mixture to the top blown smelting furnace from the top feeding port. S2. Using a smelting lance, reducing gas and process air are introduced into the smelting furnace to control the furnace temperature at 1300℃~1600℃. The mixed material floats from the top to the bottom of the furnace in a highly dispersed floating state. During this process, the reducing atmosphere is controlled to keep the oxygen partial pressure of the smelting system below 10. -20 In the process of ATM, the copper and iron oxides are mostly reduced to metallic copper and metallic iron during the falling process. These two metals then form copper-iron precious metal alloys with gold and silver in electronic waste. Rare earth oxides are not reduced and form rare earth slag phases with slag-forming agents. When the high-temperature melt obtained from the reduction in the smelting furnace falls to the bottom of the furnace, it is quickly drawn into the molten pool under the strong stirring of the gas flow from the smelting lance outlet. It is fully mixed with the solid reducing agent inside the molten pool. By controlling the amount of solid reducing agent and the ratio of reducing gas to process air, bubbles are generated inside the reduced slag, which further enhances the kinetic conditions of the reduction reaction. This allows a small portion of the unreduced copper and iron oxides to be further reduced to metallic copper and metallic iron, and the gold and silver precious metals in the slag are captured to form copper-iron precious metal alloys. S3. After the reduction process is completed, stop adding materials and reducing agents, remove the smelting torch from the molten pool for heat preservation, allow the slag to stand and separate, and discharge the copper-iron precious metal alloy melt and rare earth slag from the metal outlet and slag outlet respectively. The neodymium iron boron waste has a particle size of 50 mesh or less, and the electronic waste has a block size of 10 mm to 50 mm; The reducing atmosphere is characterized by a ratio of reducing gas to process air volume of 1:10 to 1:15, and a residual oxygen concentration of 1% to 4% in the flue gas. After reduction, the smelting flue gas passes through a secondary combustion system, a waste heat recovery system, a flue gas quenching system, an activated carbon injection system, a dust removal system, and a desulfurization system before being discharged in compliance with standards.

2. The method according to claim 1, characterized in that, The electronic waste refers to discarded electronic or electrical equipment and its components.

3. The method according to claim 1, characterized in that, The slag-forming agent is at least one of SiO2 and CaO, and its particle size is 1mm to 10mm.

4. The method according to claim 3, characterized in that, The mass fraction of iron w(Fe) in the mixture is 15%–30%, the mass fraction of silicon dioxide w(SiO2) is 25%–40%, and the mass fraction of calcium oxide w(CaO) is 15%–25%. The mixture is added from the top of the furnace at a rate of 2t / h to 6t / h.

5. The method according to claim 1, characterized in that, The reducing gas and solid reducing agent can be used as fuel.

6. The method according to claim 5, characterized in that, The reducing gas is one or more of carbon monoxide, hydrogen, natural gas, and shale gas.

7. The method according to claim 5, characterized in that, The solid reducing agent is at least one of coke and coal.

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