Resource recycling method of circuit board waste

Abstract

The invention belongs to resource recovery, and discloses a resource recycling method of circuit board waste. The resource recycling method comprises the following steps: (1) crushing the circuit board waste into powder, and carrying out hydraulic separation to obtain crude copper powder; (2) adding the crude copper powder into a mixed ammonia solution for oxidation leaching, and filtering and separating to obtain a copper ammonia solution and resin-Fe mixed slag; (3) performing multi-stage extraction and reverse extraction impurity removal purification on the copper ammonia solution, and performing spray pyrolysis to obtain electronic-grade copper oxide powder; and (4) the resin-Fe mixed slag is leached through dilute acid, resin is separated out, and the battery-grade iron phosphate is prepared from leachate through phosphate precipitation. According to the method, the circuit board waste is directly prepared into the electronic-grade copper oxide powder, on one hand, recycling of the solid waste circuit board waste is achieved, on the other hand, the electronic-grade copper oxide powder can be produced without adopting a traditional high-purity electrolytic copper raw material, and the production cost of the electronic-grade copper oxide powder is greatly reduced.

Description

Technical Field

[0001] The invention belongs to resource recovery, and in particular relates to a method for recycling waste circuit board materials. Background Art

[0002] With the rapid development of the electronics industry, the amount of electronic waste is also increasing sharply. According to the United Nations, the total amount of electronic waste generated in the world in 2022 will reach 62 million tons, and the total amount of recycling will only account for 22.3% of the generated amount. By 2030, the total amount of electronic waste in the world is expected to reach 82 million tons. The continued growth of waste circuit boards will not only cause a large amount of metal resources to be wasted, but also cause a series of environmental problems. The realization of resource recycling of waste circuit boards is not only conducive to solving potential environmental pollution problems, but also can bring considerable economic benefits.

[0003] At present, the recycling methods for waste circuit boards are mainly divided into two types: pyrometallurgy and wet leaching. The pyrometallurgy process is to obtain metal alloys by high-temperature smelting of waste circuit boards with slag-making agents. The raw materials are highly universal, the processing volume is large, and the efficiency is high, but the recovery energy consumption is high, the tail gas treatment cost is high, and the smelting products need to be further processed to achieve the separation and recovery of valuable metals. The wet leaching process is to dissolve the waste circuit boards after splitting and crushing into a solution using inorganic acids (H2SO4, HCl, HNO3), and then selectively separate the metal elements in the leachate by methods such as step-by-step precipitation and extraction, and then recover the copper salt product or recover the metal copper by methods such as electrolysis. The patent document with publication number CN112139201A discloses a resource recovery and processing method for waste circuit boards, which specifically discloses that the waste circuit boards are crushed into particles, mixed with additives, and then subjected to anaerobic pyrolysis treatment to obtain pyrolysis gas and pyrolysis solid products. The pyrolysis products are screened to obtain a variety of crude products such as copper foil, carbon powder and glass cloth, and the crude products are further separated later. Although this method realizes the resource recovery of waste circuit boards, no fine chemical products are obtained, and it can only be used as a crude product, with low economic benefits. A method for treating waste circuit boards is disclosed in the patent document with publication number CN118935414A, which specifically discloses that the waste circuit boards are crushed and sent to an incinerator for incineration to enrich valuable metals such as copper and tin in the slag, and then the separation and recovery of metal elements are realized through processes such as alkali roasting, multi-channel leaching, and iron powder replacement. The process flow is complicated and acidic wastewater is generated and needs further treatment. A method for recovering gold and copper from waste gold-plated printed circuit boards is disclosed in the patent document with publication number CN101024864A, which specifically discloses the use of hydrogen peroxide and sulfuric acid to leach gold and copper from waste gold-plated printed circuit boards. Although this method realizes the efficient leaching of copper in waste circuit boards and the stripping of gold, the leached copper solution is used for crystallization to prepare copper sulfate, the product has low economic added value, and fails to realize the comprehensive recovery of other metals in waste circuit board resources. Electronic-grade copper oxide is an indispensable material for manufacturing high-quality electronic components. It plays a key role in PCB manufacturing, especially in the production of complex circuits. The scale of China's electronic-grade copper oxide market has grown from 1.059 billion yuan in 2017 to 2.28 billion yuan in 2023, with a compound annual growth rate of 13.63%, and the market prospects are broad. The current mainstream production processes mostly use high-purity copper such as electrolytic copper and cable copper as raw materials, which have problems such as high raw material costs, long process flow, and high calcination energy consumption. Therefore, it is necessary to develop a method for preparing electronic-grade copper oxide powder by recycling waste circuit board resources with strong raw material adaptability, short preparation process, low reaction energy consumption, and green circulation. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a method for recycling waste circuit board materials.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A method for recycling waste circuit board materials, comprising the following steps: (1) Crushing the waste circuit boards into powder and hydraulically sorting them to obtain crude copper powder; (2) adding the crude copper powder into a mixed ammonia solution for oxidation leaching, filtering and separating to obtain a copper ammonia solution and a resin-Fe mixed slag; (3) subjecting the copper ammonia solution to multi-stage extraction, stripping and impurity removal, and then spray pyrolysis to obtain electronic grade copper oxide powder; (4) The resin-Fe mixed slag is leached with dilute acid to separate the resin, and the leaching solution is precipitated with phosphate to prepare battery-grade iron phosphate.

[0006] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (2), the mixed ammonia solution is dilute ammonia water to which ammonium salt is added, the molar concentration of ammonia in the dilute ammonia water is 0.5-5 mol / L, and the molar amount of ammonium salt added is 1-5 mol / L; the ammonium salt comprises at least one of ammonium bicarbonate and ammonium carbonate.

[0007] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (2), during the leaching process, the leaching temperature is 20-55°C, the liquid-to-solid ratio is 5-20, the ratio unit is mL / g, and the leaching time is 1-4 h. Within the leaching temperature and time range of the present invention, effective leaching of copper can be achieved. If the leaching time is too long, it will affect the production efficiency, and if the leaching time is too short, the copper leaching will not be thorough. If the leaching temperature is too low, the oxidation reaction of copper will be slow, affecting the leaching rate. If the leaching temperature is too high, it will easily lead to a large amount of ammonia volatilization, affecting the copper-ammonia complex and increasing the reagent consumption.

[0008] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (2), during the leaching process, the molar ratio of copper to ammonia ions in the leachate is 1:(3-10), and the oxidative leaching refers to leaching by blowing in an oxidizing atmosphere, wherein the oxygen flow rate of the oxidizing atmosphere is 0.1-0.5 L / min per liter of leachate, and the oxidizing atmosphere includes oxygen or compressed air.

[0009] In the above-mentioned method for recycling waste circuit boards, preferably, in step (3), the extractant used in the extraction process is at least one of Lix973, Lix84, and Lix54, and the diluent is selected from any one of sulfonated kerosene and kerosene; the volume fraction of the extractant in the organic phase is 5%-10%, the ratio of the organic phase to the copper ammonia solution is (1-2):1, and the extraction time is 5-10 min; 2-4 mol / L sulfuric acid is used for stripping; the number of multi-stage extraction stages is 3-6, and the content of Zn and Ni in the raffinate is less than 1 mg / L.

[0010] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (3), the concentration of Cu in the copper ammonia solution after purification is 60-140 g / L, the temperature of spray pyrolysis is 150-600°C, and the spray pressure is 0.1-0.5 MPa. If the pyrolysis temperature is too high, the copper oxide powder will sinter and increase the production energy consumption. If the spray pressure is too high, the copper oxide powder particles will be larger, which is not conducive to use in the copper plating process of integrated circuits. If the temperature is too low, the moisture in the copper oxide product will increase. If the spray pressure is too low, the production efficiency of copper oxide will be affected.

[0011] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (3), the ammonia and carbon dioxide produced in the spray pyrolysis process are absorbed by ammonia water and then returned to step (2) for reuse.

[0012] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (3), the impurity removal and purification removes Zn and Ni metal impurity ions by solvent extraction, resin adsorption, etc.

[0013] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (1), the copper content in the crude copper powder is greater than 85 wt%, and the main metal impurity components are Fe<2 wt%, Zn<1 wt%, and Ni<1 wt%.

[0014] In the above-mentioned method for recycling waste circuit board materials, preferably, in step (4), the dilute acid is any one of sulfuric acid, hydrochloric acid and nitric acid, the dilute acid concentration is 0.5-1 mol / L, the leaching liquid-solid ratio is 5-20, the ratio unit is mL / g, the leaching temperature is 20-60 °C, and the leaching time is 0.5-2 h.

[0015] In the above-mentioned method for recycling waste circuit boards, preferably, in step (4), the phosphate is any one of sodium phosphate and sodium dihydrogen phosphate, and the amount of phosphate added is 1.1 to 1.5 times the molar amount of iron in the leachate; the separated resin is dehydrated and then sold.

[0016] The chemical reactions in each step of the present invention include: (1) PCB waste is dissolved in a mixed ammonia solution under an oxidizing atmosphere. The main metal Cu is complexed with ammonia to form a copper-ammonia solution, and the main impurities Fe and resin enter the slag phase for separation: 2Cu + O2 + 4NH3 + 4NH4 + = 2Cu(NH3)4 2+ + 2H2O 2Me + O2 + 4NH3 + 4NH4 + = 2Me1(NH3)4 2++ 2H2O (Me=Zn, Ni) (2) Lix extractant is used to separate Cu, Zn and Ni impurity ions from the ammonia leachate by multi-stage extraction and sulfuric acid stripping, and a Cu-containing solution is obtained by stripping from the extracted organic phase by washing with dilute sulfuric acid. The copper-containing solution is deeply purified through multi-stage extraction and stripping. The purified copper-ammonia solution is atomized and pyrolyzed in a spray pyrolysis device to prepare electronic-grade copper oxide powder in one step. The ammonia and carbon dioxide generated during the pyrolysis process are absorbed and reused: Cu(NH3)4CO3= CuO + 4NH3↑+ CO2↑ NH3•H2O = NH3↑+ H2O↑ (NH4)2CO3= 2NH3↑+ CO2↑+ H2O↑ (3) The resin-Fe slag obtained by ammonia leaching is separated from the resin by leaching with dilute sulfuric acid. After the iron sulfate solution is purified, sodium phosphate and other phosphates are added to filter and precipitate, wash and dry to obtain the iron phosphate product for battery: Fe2(SO4)3+ 2Na3PO4= 2FePO4↓+ 3Na2SO4.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention directly prepares electronic-grade copper oxide powder from waste circuit boards, which, on the one hand, realizes the recycling of solid waste circuit boards; on the other hand, it can produce electronic-grade copper oxide powder without using traditional high-purity electrolytic copper raw materials, thereby greatly reducing the production cost of electronic-grade copper oxide powder.

[0018] (2) The present invention directly produces high-purity copper oxide powder by one-step spray pyrolysis of the purified copper ammonia solution, thereby simplifying the conventional process steps of "evaporating ammonia to prepare copper salt-high-temperature roasting of copper salt to obtain copper oxide powder". The ammonia and carbon dioxide generated by pyrolysis are absorbed and reused, the reagents are recycled, no waste water is generated, and the energy consumption and production costs are reduced.

[0019] (3) In the present invention, the resin-Fe mixed slag obtained by ammonia leaching is separated by sulfuric acid leaching to obtain resin, and then sodium phosphate solution is added to control selective precipitation to prepare iron phosphate for battery. The resin is dehydrated and then sold to achieve comprehensive recovery of impurity components of circuit board waste.

[0020] (4) Based on the selectivity of the ammonia leaching process, the present invention utilizes a mixed ammonia solution to dissolve the copper and trace amounts of Zn and Ni impurities in the crude copper material of the waste circuit board crushed in an oxidizing atmosphere, thereby achieving a deep separation of the main metal Cu from the main impurities Fe and resin, thereby reducing the pressure of subsequent impurity removal of the leaching solution; the Zn and Ni impurity ions are deeply removed through multi-stage solvent extraction and stripping, thereby achieving deep purification of the copper ammonia solution, which provides a fundamental guarantee for the subsequent preparation of electronic-grade copper oxide powder. In summary, the method for preparing electronic-grade copper oxide powder by recycling waste circuit board materials of the present invention can realize the recycling of waste copper, iron and resin in waste circuit board materials, has strong raw material adaptability, simple production steps, low energy consumption, and friendly production environment, and the prepared copper oxide powder product has high purity, good activity and dispersibility, and meets the requirements of electronic-grade copper oxide powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of recycling waste circuit board resources. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0023] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0025] The chemical composition of the waste circuit board powder treated in the following examples and comparative examples includes: Cu 87.91 wt%, Fe 0.50 wt%, Zn 0.03 wt%, Ni 0.02 wt%.

[0026] Embodiment 1: A method for recycling waste circuit board materials of the present invention has a process flow chart as shown in FIG. Figure 1 As shown, the specific steps include: (1) Crushing the waste PCB into powder and hydraulically sorting it to obtain crude copper powder and resin. The resin is dehydrated and sold.

[0027] (2) 1 mol of ammonium carbonate was added to 2 mol / L ammonia water to fully dissolve it and then the volume was fixed to obtain 500 mL of mixed ammonia solution. 50 g of crude copper powder was weighed and poured into a beaker containing the pre-prepared mixed ammonia solution for ammonia leaching. During the ammonia leaching process, the reaction temperature was controlled to 30 °C, and oxygen was introduced into the reaction container at 0.1 L / min. The reaction leaching was completed for 2 h and filtered to separate the copper-ammonia solution and resin-Fe mixed slag. After detection and analysis, the leaching rate of Cu in the leaching process was 99.75%, the Cu content in the copper-ammonia leaching solution was 87.69 g / L, the Zn and Ni impurity contents were 30 mg / L and 20 mg / L, respectively, and the impurity Fe and resin entered the slag phase for separation.

[0028] (3) The copper ammonia leaching solution was extracted with 5% Lix973-sulfonated kerosene to remove Zn and Ni impurities. The extraction ratio was 1.5:1, the number of extraction stages was 3, the extraction time was 5 min, and 3 mol / L sulfuric acid was used for back extraction. The Zn and Ni impurity contents in the purified copper ammonia solution were both less than 1 mg / L.

[0029] (4) The purified copper ammonia solution is sprayed and pyrolyzed to obtain copper oxide powder, wherein the spray pressure is 0.2 MPa and the pyrolysis temperature is 300 °C. The ammonia and carbon dioxide generated during the spray pyrolysis process are absorbed by ammonia water and reused.

[0030] (5) The resin-Fe mixed slag obtained in step (2) was leached in sulfuric acid concentration of 0.5 mol / L, liquid-to-solid ratio of 10 mL / g, and 40°C for 1 h, and the resin was filtered and separated. The resin was dehydrated and sold. Sodium phosphate with an amount of 1.2 times the theoretical molar amount of iron was added to the leached iron sulfate solution, and then stirred at 40°C for 30 min, and the precipitate was filtered, washed, and dried to obtain battery-grade iron phosphate.

[0031] After testing, the CuO content in the prepared copper oxide powder is 99.63 wt% (≥99 wt%), and the impurity elements Fe, Zn, Ni, and Mg are all ≤0.001 wt%, meeting the requirements of electronic-grade copper oxide powder. The Fe content in iron phosphate is 36.3 wt%, meeting the requirements of battery-grade iron phosphate.

[0032] Comparative Example 1: The method for recycling waste circuit board materials in this comparative example comprises the following steps: (1) Crushing the waste circuit boards into powder and hydraulically sorting them to obtain crude copper powder and resin. The resin is dehydrated and sold; (2) Add 0.1 mol of ammonium carbonate to 2 mol / L ammonia water and fully dissolve it, then adjust the volume to obtain 500 mL of mixed ammonia solution. Weigh 50 g of crude copper powder and pour it into a beaker containing the pre-prepared mixed ammonia solution for ammonia leaching. During the ammonia leaching process, the reaction temperature is controlled to 30 °C, and oxygen is introduced into the reaction container at 0.1 L / min. The reaction leaching is completed for 2 h and filtered to separate, thereby obtaining a copper-ammonia leaching solution and a resin-Fe mixed slag. After detection and analysis, the leaching rate of Cu in the leaching process is 74.36%, the Cu content in the copper-ammonia leaching solution is 60.98 g / L, and the impurity contents of Zn and Ni are 28 mg / L and 18 mg / L, respectively. In addition to impurities Fe and resin, there is also a large amount of Cu in the slag phase. (3) The copper ammonia leaching solution was extracted with 5% Lix973-sulfonated kerosene to remove Zn and Ni impurities. The extraction ratio was 1.5:1, the extraction level was 3, the extraction time was 5 min, and 3 mol / L sulfuric acid was used for stripping. The Zn and Ni impurity contents in the purified copper ammonia solution were both less than 1 mg / L. (4) spraying and pyrolyzing the purified copper ammonia solution to obtain copper oxide powder, wherein the spray pressure is 0.2 MPa and the pyrolysis temperature is 300 °C, and the ammonia and carbon dioxide generated during the spray pyrolysis process are absorbed by ammonia water and reused; (5) Since copper is not fully dissolved during the ammonia leaching process, the mixed slag obtained in step (2) contains a large amount of copper. The ammonia leaching process needs to be repeated to allow Cu to fully dissolve into the leaching solution for separation before the resin and Fe can be further separated and recovered.

[0033] After testing, the CuO content in the product copper oxide powder is 99.25 wt% (≥99 wt%), and the impurity elements Fe, Zn, Ni, and Mg are all ≤0.001 wt%, meeting the requirements of electronic grade copper oxide powder. However, by comparing Example 1 with Comparative Example 1, it can be seen that when the amount of ammonium salt added during the ammonia leaching process is insufficient, the Cu in the circuit board waste cannot be fully dissolved within the expected time, affecting the subsequent separation.

[0034] Embodiment 2: A method for recycling waste circuit board materials of the present invention has a process flow chart as shown in FIG. Figure 1 As shown, the specific steps include: (1) Crushing the waste circuit boards into powder and hydraulically sorting them to obtain crude copper powder and resin. The resin is dehydrated and sold; (2) Add 0.75 mol of ammonium carbonate to 2 mol / L ammonia water and fully dissolve it, then adjust the volume to obtain 500 mL of mixed ammonia solution. Weigh 50 g of crude copper powder and pour it into a beaker containing the pre-prepared mixed ammonia solution for ammonia leaching. During the ammonia leaching process, the reaction temperature is controlled to 30 °C, and oxygen is introduced into the reaction container at 0.1 L / min. The reaction leaching is completed for 2 h and filtered to separate to obtain copper ammonia solution and resin-Fe mixed slag. After detection and analysis, the leaching rate of Cu in the leaching process is 99.21%, the Cu content in the copper ammonia leaching solution is 87.22 g / L, and the impurity contents of Zn and Ni are 30 mg / L and 20 mg / L, respectively. Impurities Fe and resin enter the slag phase for separation. (3) The copper ammonia leaching solution was extracted with 5% Lix973-sulfonated kerosene to remove Zn and Ni impurities. The extraction ratio was 1.5:1, the extraction level was 3, the extraction time was 5 min, and 3 mol / L sulfuric acid was used for back extraction. The impurity contents of Zn and Ni in the purified copper ammonia solution were both less than 1 mg / L. The impurity contents of Zn and Ni in the purified copper ammonia solution were both less than 1 mg / L; (4) spraying and pyrolyzing the purified copper ammonia solution to obtain copper oxide powder, wherein the spray pressure is 0.3 MPa, the pyrolysis temperature is 150 °C, and the ammonia and carbon dioxide generated in the spray pyrolysis process are absorbed by ammonia water and reused; (5) The resin-Fe mixed slag obtained in step (2) was leached in sulfuric acid concentration of 0.5 mol / L, liquid-to-solid ratio of 10 mL / g, and 40°C for 1 h, and the resin was separated by filtration. The resin was dehydrated and sold. Sodium phosphate with an amount of 1.3 times the theoretical molar amount of iron was added to the leached iron sulfate solution, and then stirred at 40°C for 30 min. The precipitate was filtered, washed, and dried to obtain battery-grade iron phosphate.

[0035] After testing, the CuO content in the product's copper oxide powder is 99.61 wt% (≥99 wt%), and the impurity elements Fe, Zn, Ni, and Mg are all ≤0.001 wt%, meeting the requirements of electronic-grade copper oxide powder. The Fe content in iron phosphate is 36.1 wt%, meeting the requirements of battery-grade iron phosphate.

[0036] Comparative Example 2: The method for recycling waste circuit board materials in this comparative example comprises the following steps: (1) Crushing the waste circuit boards into powder and hydraulically sorting them to obtain crude copper powder and resin. The resin is dehydrated and sold; (2) Add 0.75 mol of ammonium carbonate to 2 mol / L ammonia water and fully dissolve it, then adjust the volume to obtain 500 mL of mixed ammonia solution. Weigh 50 g of crude copper powder and pour it into a beaker containing the pre-prepared mixed ammonia solution for ammonia leaching. During the ammonia leaching process, the reaction temperature is controlled to 30 °C, and oxygen is introduced into the reaction container at 0.1 L / min. The reaction leaching is completed for 2 h and filtered to separate to obtain copper ammonia solution and resin-Fe mixed slag. After detection and analysis, the leaching rate of Cu in the leaching process is 99.21%, the Cu content in the copper ammonia leaching solution is 87.22 g / L, and the impurity contents of Zn and Ni are 30 mg / L and 20 mg / L, respectively. Impurities Fe and resin enter the slag phase for separation. (3) The copper ammonia leaching solution was extracted with 5% Lix973-sulfonated kerosene to remove Zn and Ni impurities. The extraction ratio was 1.5:1, the extraction level was 3, the extraction time was 5 min, and 3 mol / L sulfuric acid was used for back extraction. The impurity contents of Zn and Ni in the purified copper ammonia solution were both less than 1 mg / L. The impurity contents of Zn and Ni in the purified copper ammonia solution were both less than 1 mg / L; (4) The purified copper ammonia solution was sprayed and pyrolyzed to obtain copper oxide powder, wherein the spray pressure was 0.05 MPa and the pyrolysis temperature was 120 °C. The ammonia and carbon dioxide generated during the spray pyrolysis process were absorbed and recycled by ammonia water. The prepared copper oxide powder was not fully dried and had a high moisture content. (5) The resin-Fe mixed slag obtained in step (2) was leached in sulfuric acid at a concentration of 0.5 mol / L, a liquid-to-solid ratio of 10 mL / g, and 40°C for 1 h, and the resin was filtered and separated. The resin was dehydrated and sold. Sodium phosphate with an amount of 1.3 times the theoretical molar amount of iron was added to the leached iron sulfate solution, and then stirred at 40°C for 30 min. The precipitate was filtered, washed, and dried to obtain battery-grade iron phosphate.

[0037] After testing, the CuO content in the product copper oxide powder was 98.63 wt%, which did not meet the requirements of electronic grade copper oxide powder.

[0038] By comparing Example 2 and Comparative Example 2, it can be seen that when the spray pressure in the spray pyrolysis process is too small or the spray temperature is too low, the fluidity of the atomizing gas decreases, the moisture content of the obtained copper oxide powder increases, and it is difficult to directly obtain electronic grade copper oxide powder that meets the requirements.

Claims

1. A method for recycling waste circuit board materials, characterized in that: The following steps are involved: (1) Crushing the waste circuit boards into powder and hydraulically sorting them to obtain crude copper powder; (2) adding the crude copper powder into a mixed ammonia solution for oxidation leaching, filtering and separating to obtain a copper ammonia solution and a resin-Fe mixed slag; (3) subjecting the copper ammonia solution to multi-stage extraction, stripping and impurity removal, and then spray pyrolysis to obtain electronic grade copper oxide powder; (4) The resin-Fe mixed slag is leached with dilute acid to separate the resin, and the leaching solution is precipitated with phosphate to prepare battery-grade iron phosphate.

2. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (2), the mixed ammonia solution is dilute ammonia water to which ammonium salt is added, the molar concentration of ammonia in the dilute ammonia water is 0.5-5 mol / L, and the molar amount of ammonium salt added is 1-5 mol / L; the ammonium salt comprises at least one of ammonium bicarbonate and ammonium carbonate.

3. The method for recycling waste circuit board materials according to claim 1, characterized in that: In step (2), during the leaching process, the leaching temperature is 20-55°C, the liquid-to-solid ratio is 5-20, the ratio unit is mL / g, and the leaching time is 1-4 h.

4. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (2), during the leaching process, the molar ratio of copper to ammonia ions in the leachate is 1:(3-10), and the oxidative leaching refers to leaching by blowing in an oxidizing atmosphere, wherein the oxygen flow rate of the oxidizing atmosphere is 0.1-0.5 L / min per liter of leachate, and the oxidizing atmosphere includes oxygen or compressed air.

5. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (3), the extractant used in the extraction process is at least one of Lix973, Lix84, and Lix54, and the diluent is selected from any one of sulfonated kerosene and kerosene; the volume fraction of the extractant in the organic phase is 5%-10%, the ratio of the organic phase to the copper ammonia solution is (1-2):1, and the extraction time is 5-10 min; 2-4 mol / L sulfuric acid is used for back extraction; the number of multi-stage extraction stages is 3-6, and the content of Zn and Ni in the raffinate is less than 1 mg / L.

6. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (3), the Cu concentration in the copper ammonia solution after purification is 60-140 g / L, the temperature of spray pyrolysis is 150-600°C, and the spray pressure is 0.1-0.5 MPa.

7. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (3), ammonia and carbon dioxide generated in the spray pyrolysis process are absorbed by ammonia water and then returned to step (2) for reuse.

8. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (1), the copper content in the crude copper powder is greater than 85 wt%, and the main metal impurity components are Fe<2 wt%, Zn<1 wt%, and Ni<1 wt%.

9. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (4), the dilute acid is any one of sulfuric acid, hydrochloric acid and nitric acid, the dilute acid concentration is 0.5-1 mol / L, the leaching liquid-solid ratio is 5-20, the ratio unit is mL / g, the leaching temperature is 20-60 °C, and the leaching time is 0.5-2 h.

10. The method for recycling waste circuit board materials as claimed in claim 1, characterized in that: In step (4), the phosphate is any one of sodium phosphate and sodium dihydrogen phosphate, and the amount of phosphate added is 1.1 to 1.5 times the molar amount of iron in the leachate; the separated resin is dehydrated and sold.

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