A method for efficiently and directionally separating valuable components from waste printed circuit board pyrolysis products

Abstract

The application discloses a kind of valuable components of waste circuit board pyrolysis product high-efficiency directional separation methods, comprising the following steps: waste circuit board pyrolysis-alkali liquor spray separation oil gas mixture-pyrolysis residue crushing and hydrocyclone classification-pyrolysis residue coarse / fine particle mixture sorting-metal enrichment body fine grinding-sulfuration-flotation.The application plays a promoting role for the high-value recycling of waste circuit board, and is a high recycling rate, small environmental pollution, high-efficiency separation technology, with wide application prospect.

Description

Technical Field

[0001] This invention relates to a method for the directional separation of valuable components from waste circuit boards, belonging to the field of comprehensive recycling of valuable components from typical waste composite materials. In particular, it relates to an efficient directional separation method for recovering copper from waste circuit board pyrolysis slag through crushing, hydrocyclone classification, eddy current separation, shaking table separation, and sulfide flotation. Background Technology

[0002] Waste printed circuit boards (PCBs) are the fastest-growing type of solid waste composite material in municipal solid waste. Domestic and international research institutions have conducted extensive research on the resource recovery and utilization of waste PCBs. Currently, the mainstream recycling methods include physical sorting, pyrometallurgical processing, and hydrometallurgical processing. For example, Umicore in Belgium uses ISA smelting technology to process waste PCBs and copper concentrate, while Porden in Sweden uses smelting technology and smelting furnaces to recycle waste PCBs. However, different recycling methods still have several problems that need to be solved. For instance, the crushing process in physical sorting methods easily generates polluting gases, causing environmental pollution, and the separation efficiency of metals and non-metals is relatively low. While hydrometallurgical processing has a high metal recovery rate, it easily causes environmental pollution, requiring the search for low-toxicity leaching agents. Pyrometallurgical direct smelting technology easily generates polluting gases, has low utilization of valuable components, and easily pollutes the environment, requiring large amounts of exhaust gas treatment equipment, resulting in high costs.

[0003] In contrast, pyrolysis has significant advantages in recycling waste circuit boards, enabling the high-value recovery and reuse of all valuable components, such as metals, resins, and glass fibers. However, pyrolysis for waste circuit board processing currently lacks large-scale industrial application, primarily due to the difficulty in separating valuable metals and non-metals after pyrolysis, resulting in low metal recovery rates and the inability to recycle non-metals at high value. The presence of organic matter such as epoxy or phenolic resins leads to a layer of fine carbon particles adhering to the surface of the solid product after pyrolysis, making metal and carbon separation difficult. Direct calcination not only oxidizes the metals but also renders the calorific value of the carbon unusable.

[0004] To address the problems of low metal and non-metal recycling rates, environmental pollution, difficulty in separating valuable components, and inability to utilize valuable products at high value in the current waste circuit board pyrolysis process, this invention proposes a highly efficient directional separation method for waste circuit board pyrolysis slag, which involves crushing, hydrocyclone classification, eddy current separation, shaking table separation, and sulfide flotation. This method not only achieves directional separation of metals and non-metals in the pyrolysis slag but also separates the main metal, copper, from other metals in the waste circuit boards, achieving the goals of low environmental pollution, high organic component recycling rate, and simple and easy-to-implement process. Summary of the Invention

[0005] This invention provides a highly efficient and directional separation method for valuable components in the pyrolysis products of waste circuit boards, solving the problems of difficult recovery and separation of valuable products in traditional mechanical processing methods for waste circuit boards. The pyrolysis method enables the directional separation and recovery of organic matter in waste circuit boards, and the high-value recovery of pyrolysis gas and pyrolysis oil. The pyrolysis residue mainly contains metal mixtures such as copper, iron, and lead, and non-metal mixtures such as glass fiber and carbon. The pyrolysis gas can be reused in the pyrolysis stage of waste circuit boards, and the heat generated during the pyrolysis of the steel strip furnace can be used in the hydrothermal sulfidation stage of the pyrolysis residue and the spraying stage of the oil-gas mixture. A drum ball mill is used to crush the pyrolysis residue, reducing the particle size of the waste circuit board particles. A hydrocyclone is used for classification, separating the coarse particle underflow from the fine particle overflow. The fine particle mixture is subjected to eddy current separation, and the coarse particle mixture is subjected to shaking table separation to obtain non-metallic enriched group 1 (fine particle resin powder, carbon, etc.), metal enriched group 1 (copper, iron, lead, etc.), and non-metallic enriched group 2 (coarse particle resin powder, etc.). Metal-rich aggregate 1 was finely ground using a horizontal ball mill to obtain metal-rich aggregate 2 after particle size reduction. The metal-rich aggregate 2 was then subjected to hydrothermal sulfidation with the addition of a sulfidation accelerator (MBT). Water glass, Z200, and No. 2 oil were then added for flotation to obtain metallic copper and metal-rich aggregate 3 (iron, lead, etc.). This process of directional separation of valuable components from waste circuit boards enables the high-value recovery and utilization of organic matter in waste circuit boards, and also allows for the directional separation of metallic copper from other metals, significantly improving the high-value recovery rate and directional separation efficiency of valuable components.

[0006] The raw materials used in the above scheme include: rinsing solution—NaOH, vulcanization accelerator—MBT (2-mercaptobenzothiazole), modifier—water glass, collector—Z200 (ethyl thiocyanate), and foaming agent—No. 2 oil.

[0007] This invention provides a method for efficient and directional separation of valuable components from waste circuit board pyrolysis products, comprising the following steps:

[0008] (1) Waste circuit board pyrolysis: Waste circuit boards are processed using a continuous feed steel strip pyrolysis furnace. N2 is introduced into the pyrolysis furnace as a protective gas. The heating temperature and heating rate are controlled to pyrolyze the waste circuit boards, resulting in pyrolysis residue and an oil-gas mixture containing pyrolysis gas and pyrolysis oil.

[0009] Preferably, the pyrolysis furnace uses natural gas and pyrolysis gas generated by the system as fuel, and the generated flue gas is sent to the boiler for cooling and heat recovery from the pyrolysis flue gas.

[0010] Preferably, the initial pyrolysis temperature is 150–250°C, the final temperature is 450–550°C, and the pyrolysis time is 100–150 min. A three-stage zoned temperature control heating method is employed: zone one at 150–250°C, zone two at 250–450°C, and zone three at 450–550°C. In this invention, the circuit board pyrolysis temperature range is 150–550°C. The zoned heating method improves the pyrolysis effect, achieving an organic matter pyrolysis rate of 97%–99% after the three-stage zoned pyrolysis.

[0011] The pyrolysis slag is mainly composed of a mixture of metals such as copper, iron, and lead, and a mixture of non-metals such as glass fiber and carbon. The main components of the pyrolysis gas include lower aliphatic hydrocarbons, low molecular weight aromatic hydrocarbons, hydrogen bromide, carbon monoxide, and carbon dioxide. The main components of the pyrolysis oil include phenols such as phenol, 4-isopropylphenol, and 2-isopropylphenol.

[0012] (2) Alkali spray separation of oil and gas mixture: The oil and gas mixture generated after the pyrolysis of waste circuit boards is sent to the alkaline spray tower for condensation. The acidic gas hydrogen bromide is absorbed by the alkaline solution. After condensation, oil and gas separation is carried out. The gaseous products are passed through the oil replenisher to finally obtain pyrolysis gas, pyrolysis oil and sodium bromide.

[0013] Preferably, the alkaline solution used is a NaOH solution with a mass concentration of 3% to 10%.

[0014] During the alkaline spraying process, acidic gases (such as HBr) in the oil-gas mixture are absorbed by the NaOH solution to produce NaBr. The NaBr solution is then evaporated by the heat from the flue gas boiler to obtain NaBr. At the same time, pyrolysis oil and pyrolysis gas are separated, and the pyrolysis oil replenishment rate ranges from 96% to 99%.

[0015] (3) Pyrolysis residue crushing and hydrocyclone classification: The pyrolysis residue is crushed by a drum ball mill, and the crushed products are classified by a hydrocyclone. The feed pressure and hydrocyclone parameters are determined. The underflow obtains a coarse particle mixture, and the overflow obtains a fine particle mixture.

[0016] Preferably, the particle size of the crushed product is 0.05–20 mm, the overflow pipe diameter of the hydrocyclone is 170–240 mm, the feed pressure is 0.05–0.2 MPa, and the sand discharge nozzle diameter is 85–150 mm. The parameter settings of the hydrocyclone affect the particle size distribution of the mixture of coarse and fine particles, and the above parameters, within a certain range, help to separate coarse and fine particles.

[0017] Preferably, the coarse particle mixture has a particle size range of 2.0 mm to 20 mm, and the fine particle mixture has a particle size range of 0.05 mm to 2.0 mm. The coarse particle mixture and the fine particle mixture have the same composition, both being pyrolysis slag.

[0018] (4) Sorting of coarse / fine pyrolysis residue mixture: The coarse pyrolysis residue mixture is sorted by shaking table sorting method and the fine pyrolysis residue mixture is sorted by eddy current sorting method. The metals obtained by the two sorting methods are mixed to obtain a metal enrichment 1 containing metals such as Cu, Fe, Pb, and Pd, and a non-metal enrichment 1 containing SiO2 and C is obtained at the same time.

[0019] Since shaking table separation is a type of gravity separation, it is suitable for separating coarse particles; therefore, shaking table separation is used to separate coarse particle mixtures. Eddy current separation is suitable for separating fine particles; therefore, eddy current separation is used to separate fine particle mixtures. These separation methods can separate metals and non-metals. Standard settings for the separation parameters are sufficient.

[0020] (5) Fine grinding-sulfidation-flotation of metal enrichment: Metal enrichment 1 is finely ground using a horizontal ball mill to reduce particle size and obtain metal enrichment 2. A sulfidation accelerator is added to metal enrichment 2 for hydrothermal sulfidation, and a modifier, collector and frother are added for flotation to recover copper and obtain metal Cu and metal enrichment 3.

[0021] Preferably, a horizontal ball mill is used to finely grind the metal enrichment 1, the particle size of the metal enrichment 2 is in the range of 0.03 mm to 0.1 mm, and the slurry concentration of the metal enrichment 2 is 25% to 35%.

[0022] Preferably, the vulcanization accelerator is MBT, the modifier is water glass, the collector is Z200, and the foaming agent is No. 2 oil.

[0023] Preferably, the concentration range of the sulfidation accelerator MBT is 100-200 g / t, the concentration range of the modifier water glass is 50-300 g / t, the concentration range of the collector Z200 is 120-320 g / t, the concentration range of the foaming agent No. 2 oil is 20-100 g / t, and the copper recovery rate is 85%-92%.

[0024] The present invention has the following beneficial effects:

[0025] Waste circuit boards are typical organic-inorganic composite solid waste. Based on the pyrolysis characteristics of their organic components, a chain-type continuous pyrolysis furnace is used to pyrolyze high-molecular-weight organic materials such as epoxy resin. The resulting pyrolysis oil-gas mixture is further processed to obtain sodium bromide, and the generated pyrolysis gas can continuously supply energy to the system. For the pyrolysis slag, methods such as crushing, hydrocyclone classification, fine grinding, hydrothermal sulfidation, and flotation are used to separate metallic copper from other metal mixtures, achieving efficient and targeted recovery and utilization of valuable components from the pyrolysis products.

[0026] Compared with traditional processes, this method achieves efficient and directional separation of copper, the main metal in waste circuit boards. The heat generated by pyrolysis flue gas is reused in the hydrothermal sulfidation stage and the alkaline spraying stage, saving a lot of energy and avoiding a large amount of pollutants generated by traditional incineration processes. At the same time, it realizes the high-value recycling and utilization of different valuable components in waste circuit boards. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart of the efficient directional separation method for valuable components in waste circuit board pyrolysis products according to the present invention. Detailed Implementation

[0029] The examples used the same batch of waste circuit boards (computer motherboards). Elemental analysis showed that the mass percentages of Cu, C, H, and Br were 31.32%, 20.82%, 2.18%, and 4.78%, respectively; industrial analysis showed that the mass percentages of ash, volatile matter, moisture, and fixed carbon were 64.28%, 25.23%, 0.06%, and 10.43%, respectively. Specific examples are shown below:

[0030] Example 1

[0031] Waste circuit boards were fed into a continuous feed steel strip pyrolysis furnace, and N2 was introduced as a protective gas. The initial pyrolysis temperature was set to 200℃ and the final temperature to 550℃. The continuous feed steel strip pyrolysis furnace was heated in three stages with zoned temperature control: zone one at 200℃, zone two at 350℃, and zone three at 550℃, with a pyrolysis time of 120 minutes. After pyrolysis, an oil-gas mixture and pyrolysis residue were obtained. The organic matter pyrolysis rate after the three-stage zoned pyrolysis was 97.9%.

[0032] The oil-gas mixture was fed into a condensation spray tower. The NaOH solution used had a mass concentration of 6%. After spraying, the pyrolysis gas and pyrolysis oil were separated, and NaBr was obtained simultaneously. The pyrolysis oil replenishment rate was 96%.

[0033] The pyrolysis residue is crushed, and the particle size range after crushing is 0.05-16mm. The overflow pipe diameter in the hydrocyclone is 200mm, the feed pressure is 0.1Mpa, and the sand discharge nozzle diameter is 120mm. The underflow yields a coarse particle mixture, and the overflow yields a fine particle mixture.

[0034] The coarse particle mixture and the fine particle mixture were separated by shaking table separation method and eddy current separation method, respectively, to obtain metal-rich mass 1, non-metal-rich mass 1, and non-metal-rich mass 2.

[0035] Metal enrichment 1 was finely ground using a horizontal ball mill to obtain metal enrichment 2 with a particle size range of 0.03 mm to 0.1 mm and a slurry concentration of 30%. Metal enrichment 2 was then subjected to hydrothermal sulfidation with MBT (150 g / t) as a sulfidation accelerator. The concentrations of water glass (200 g / t), collector Z200 (220 g / t), and frother No. 2 oil (50 g / t) were also included. The copper recovery rate was 88.6%.

[0036] Example 2

[0037] Waste circuit boards were fed into a continuous feed steel strip pyrolysis furnace, and N2 was introduced as a protective gas. The initial pyrolysis temperature was set to 180℃ and the final temperature to 550℃. The continuous feed steel strip pyrolysis furnace was heated in three stages with zoned temperature control: zone one at 180℃, zone two at 320℃, and zone three at 550℃, with a pyrolysis time of 150 minutes. After pyrolysis, an oil-gas mixture and pyrolysis residue were obtained. The organic matter pyrolysis rate was 97% after the three-stage zoned pyrolysis.

[0038] The oil-gas mixture was fed into a condensation spray tower. The NaOH solution used had a mass concentration of 10%. After spraying, the pyrolysis gas and pyrolysis oil were separated, and NaBr was obtained simultaneously. The pyrolysis oil replenishment rate was 99%.

[0039] The pyrolysis residue is crushed, and the particle size range after crushing is 0.05-20mm. The overflow pipe diameter in the hydrocyclone is 220mm, the feed pressure is 0.15Mpa, and the sand discharge nozzle diameter is 150mm. The underflow yields a coarse particle mixture, and the overflow yields a fine particle mixture.

[0040] The coarse particle mixture and the fine particle mixture were separated by shaking table separation method and eddy current separation method, respectively, to obtain metal-rich mass 1 and non-metal-rich mass 1 and non-metal-rich mass 2.

[0041] Metal enrichment 1 was finely ground using a horizontal ball mill to obtain metal enrichment 2 with a particle size range of 0.03 mm to 0.1 mm and a slurry concentration of 30%. Metal enrichment 2 was then subjected to hydrothermal sulfidation with MBT (180 g / t) as a sulfidation accelerator. The concentrations of water glass (150 g / t), collector Z200 (300 g / t), and frother No. 2 oil (50 g / t) were also included. The copper recovery rate was 92%.

[0042] Example 3

[0043] Waste circuit boards were fed into a continuous feed steel strip pyrolysis furnace, and N2 was introduced as a protective gas. The initial pyrolysis temperature was set to 180℃ and the final temperature to 520℃. The continuous feed steel strip pyrolysis furnace was heated in three stages with zoned temperature control: zone one at 180℃, zone two at 400℃, and zone three at 520℃, with a pyrolysis time of 150 minutes. After pyrolysis, an oil-gas mixture and pyrolysis residue were obtained. The organic matter pyrolysis rate after the three-stage zoned pyrolysis was 98.2%.

[0044] The oil-gas mixture was fed into a condensation spray tower. The NaOH solution used had a mass concentration of 8%. After spraying, the pyrolysis gas and pyrolysis oil were separated, and NaBr was obtained simultaneously. The pyrolysis oil replenishment rate was 97.5%.

[0045] The pyrolysis slag is crushed, and the particle size range after crushing is 0.05-20mm. The overflow pipe diameter in the hydrocyclone is 180mm, the feeding pressure is 0.15Mpa, and the sand discharge nozzle diameter is 130mm. The underflow yields a coarse particle mixture, and the overflow yields a fine particle mixture.

[0046] The coarse particle mixture and the fine particle mixture were separated by shaking table separation method and eddy current separation method, respectively, to obtain metal-rich mass 1, non-metal-rich mass 1, and non-metal-rich mass 2.

[0047] Metal enrichment 1 was finely ground using a horizontal ball mill to obtain metal enrichment 2 with a particle size range of 0.03 mm to 0.1 mm and a slurry concentration of 28%. Metal enrichment 2 was then subjected to hydrothermal sulfidation with the addition of sulfidation accelerator MBT at a concentration of 160 g / t. The concentrations of water glass as a modifier were 100 g / t, collector Z200 at 180 g / t, and frother No. 2 oil at 60 g / t. The copper recovery rate was 90.1%.

[0048] Example 4

[0049] Waste circuit boards were fed into a continuous feed steel strip pyrolysis furnace, and N2 was introduced as a protective gas. The initial pyrolysis temperature was set to 240℃ and the final temperature to 550℃. The continuous feed steel strip pyrolysis furnace was heated in three stages with zoned temperature control: zone one at 240℃, zone two at 390℃, and zone three at 550℃. The pyrolysis time was 130 minutes. After pyrolysis, an oil-gas mixture and pyrolysis residue were obtained. The organic matter pyrolysis rate was 99% after the three-stage zoned pyrolysis.

[0050] The oil-gas mixture was fed into a condensation spray tower. The NaOH solution used had a mass concentration of 10%. After spraying, the pyrolysis gas and pyrolysis oil were separated, and NaBr was obtained simultaneously. The pyrolysis oil replenishment rate was 99%.

[0051] The pyrolysis residue is crushed, and the particle size range after crushing is 0.05-18mm. The overflow pipe diameter in the hydrocyclone is 190mm, the feeding pressure is 0.2Mpa, and the sand discharge nozzle diameter is 150mm. The underflow yields a coarse particle mixture, and the overflow yields a fine particle mixture.

[0052] The coarse particle mixture and the fine particle mixture were separated by shaking table separation method and eddy current separation method, respectively, to obtain metal-rich mass 1, non-metal-rich mass 1, and non-metal-rich mass 2.

[0053] Metal enrichment 1 was finely ground using a horizontal ball mill to obtain metal enrichment 2 with a particle size range of 0.03 mm to 0.1 mm and a slurry concentration of 35%. Metal enrichment 2 was then subjected to hydrothermal sulfidation with the addition of sulfidation accelerator MBT at a concentration of 170 g / t. The concentrations of water glass as a modifier were 280 g / t, collector Z200 at 300 g / t, and frother No. 2 oil at 70 g / t. The copper recovery rate was 91.1%.

[0054] Comparative Example 1

[0055] Comparative Example 1 and Example 1 have basically the same process steps, except that the three-stage zoned temperature control heating was not used in step 1). The specific heating method is as follows: the temperature inside the pyrolysis furnace is maintained at 400°C, the pyrolysis time is 120 min, and after pyrolysis, an oil-gas mixture and pyrolysis residue are obtained. The pyrolysis rate of organic matter is 80.4%.

[0056] The pyrolysis oil replenishment rate was 90.2%;

[0057] The copper recovery rate was 85.0%.

[0058] Compared with Example 1, since the three-stage zoned temperature control heating was not used, the pyrolysis rate of organic matter in Comparative Example 1 decreased significantly, resulting in more long-chain components remaining in the pyrolysis oil. These components were not easy to replenish during the condensation stage, and therefore the replenishment rate of the pyrolysis oil also decreased significantly.

[0059] Comparative Example 2

[0060] Comparative Example 2 is basically the same as Example 1 in terms of process steps, except that the hydrocyclone setting parameters in step 3) are different. The specific parameters are: overflow pipe diameter is 300mm, feeding pressure is 0.1Mpa, and sand discharge nozzle diameter is 200mm.

[0061] The copper recovery rate was 76.6%.

[0062] Compared with Example 1, the copper recovery rate of Comparative Example 2 was significantly reduced due to the change in hydrocyclone settings and incomplete separation of coarse and fine particles.

[0063] Comparative Example 3

[0064] Comparative Example 3 is basically the same as Example 1 in terms of process steps, except that the separation method of coarse and fine particle mixture in step 4) is different. Specifically, both coarse and fine particle mixtures are separated by shaking table separation method.

[0065] The copper recovery rate was 80.4%.

[0066] Compared with Example 1, the copper recovery rate of Comparative Example 3 was significantly reduced because the fine particles were not completely separated due to the appropriate sorting method used for the mixture of coarse and fine particles.

[0067] Comparative Example 4

[0068] Comparative Example 4 is basically the same as Example 1 in terms of process steps, except that in step 5), the sulfurizing agent MBT and collector Z200 are not added. The specific parameters are: water glass concentration is 200g / t, and foaming agent No. 2 oil concentration is 50g / t.

[0069] The copper recovery rate was 60.4%.

[0070] Compared to Example 1, the copper recovery rate of Comparative Example 4 was significantly lower due to the absence of sulfiding agents and collectors.

[0071] Compared with traditional waste circuit board recycling processes, this invention proposes a novel and highly efficient method for separating pyrolysis products from waste circuit boards. For example... Figure 1 As shown, this method can effectively separate metals and non-metals from waste circuit boards, and also separate the main metal, copper, from other metals. Through pyrolysis, high-molecular-weight organic materials such as epoxy resin or phenolic resin are converted into a mixture of solid carbon and oil-gas under anaerobic high temperature. The pyrolysis slag is then classified through crushing and hydrocyclone processes, separating the coarse and fine particle mixtures. The overflow contains a large amount of fine carbon particles, while the heavier metals and coarse particle mixture enter the underflow. The fine particle mixture is further separated into metals and non-metals by eddy current separation, while the coarse particle mixture is separated into metals and non-metals by shaking table separation. The mixed metal mixture is hydrothermally vulcanized by adding a vulcanization accelerator, and copper is recovered by flotation with the addition of modifiers, collectors, and frothers. Simultaneously, the pyrolysis gas is reused to continuously power the pyrolysis system, and the pyrolysis heat is recycled to the hydrothermal vulcanization stage and the oil-gas mixture washing stage. Through the pyrolysis and separation process, efficient and directional separation and enrichment of different valuable components of the waste circuit board pyrolysis products are achieved. Therefore, this invention promotes the high-value recycling of waste circuit boards and is a technology with high recycling rate, low environmental pollution, and high separation efficiency, with broad application prospects.

[0072] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this invention, and these modifications or substitutions should all be covered within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. A method for efficient directional separation of valuable components from waste printed circuit board pyrolysis products, characterized in that, It consists of the following steps: (1) Waste circuit board pyrolysis: using a continuous feeding type steel belt pyrolysis furnace to treat waste circuit boards, the pyrolysis furnace is connected with N2 as protective gas, so that the waste circuit boards are pyrolyzed, and pyrolysis residue and oil gas mixture containing pyrolysis gas and pyrolysis oil are obtained; In step (1), the initial pyrolysis temperature is 150-250℃, the end temperature is 450-550℃, and the pyrolysis time is 100-150min; three-stage partition temperature control heating is adopted, one partition temperature is 150-250℃, two partition temperature is 250-450℃, and three partition temperature is 450-550℃; (2) Alkaline solution spraying separates oil gas mixture: the oil gas mixture is sent into an alkaline solution spraying tower for condensation, and the acidic gas hydrogen bromide is absorbed by the alkaline solution, and after condensation, oil gas separation is carried out, the gas phase product passes through an oil supplement device, and finally pyrolysis gas, pyrolysis oil and sodium bromide are obtained; (3) Pyrolysis residue crushing and hydrocyclone classification: a drum-type ball mill is used to crush the pyrolysis residue, and the crushed product is classified by a hydrocyclone, the underflow obtains a coarse particle mixture, and the overflow obtains a fine particle mixture; In step (3), the particle size of the crushed product is 0.05-20mm, the overflow pipe diameter of the hydrocyclone is 170-240mm, the feed pressure is 0.05-0.2Mpa, and the sand discharge nozzle diameter is 85-150mm; the particle size range of the coarse particle mixture is 2.0mm-20mm, and the particle size range of the fine particle mixture is 0.05mm-2.0mm; (4) Pyrolysis residue coarse / fine particle mixture separation: the coarse particle mixture is separated by a shaking table separation method, and the fine particle mixture is separated by an eddy current separation method, the metals obtained by the two separation methods are mixed to obtain a metal concentrate 1 containing Cu, Fe, Pb and Pd metals, and a non-metallic concentrate containing SiO2 and C is also obtained; (5) Fine grinding-sulfidation-flotation of metal concentrate: a horizontal ball mill is used to finely grind the metal concentrate 1 to reduce the particle size, and a metal concentrate 2 is obtained, a sulfidation promoter is added to the metal concentrate 2 for hydrothermal sulfidation, and an adjusting agent, a collector and a foaming agent are added to float and recover copper to obtain metal Cu and a metal concentrate 3; In step (5), the metal concentrate 1 is finely ground by a horizontal ball mill, and the particle size range of the metal concentrate 2 is 0.03mm-0.1mm; In step (5), the pulp concentration of the metal concentrate 2 is 25%-35%, the sulfidation promoter is MBT, and the concentration range is 100-200g / t; the adjusting agent is water glass, and the concentration range is 50-300g / t; the collector is Z200, and the concentration range is 120-320g / t; the foaming agent is No.2 oil, and the concentration range is 20-100g / t; the copper recovery rate range is 85%-92%.

2. The method of claim 1, wherein, In step (1), the pyrolysis furnace uses natural gas and pyrolysis gas generated by the system as fuel, and the flue gas is sent to a boiler for cooling and recovering heat from the pyrolysis flue gas.

3. The method of claim 1, wherein, In step (2), the alkaline solution used is NaOH solution with a mass concentration of 3%-10%.

4. The method of claim 1, wherein, In step (2), the pyrolysis oil make-up rate is in the range of 96% to 99%.

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