Method for preparing copper oxide by synergistically recovering waste etching liquid and crude copper powder of waste circuit board

Abstract

The invention belongs to the field of resource recovery treatment, and discloses a method for preparing copper oxide by synergistically recovering waste etching liquid and waste circuit board crude copper powder, which comprises the following steps: adding the waste circuit board crude copper powder and a leaching complexing agent water-soluble chlorine salt into the waste etching liquid, stirring, leaching, filtering and separating to obtain a copper-chlorine complex solution; adding a reducing agent ascorbic acid into the copper chloride complex solution for reaction, filtering and separating to obtain CuCl precipitate; uniformly mixing the CuCl precipitate with auxiliary dechlorination salt, performing controlled atmosphere roasting, and washing a roasted product to obtain copper oxide or cuprous oxide; the auxiliary dechlorination salt is at least one of sodium carbonate, sodium bicarbonate and sodium hydroxide; wherein when the roasting atmosphere is an oxidizing atmosphere, the roasted product is washed with water after roasting to obtain copper oxide; and when the roasting atmosphere is inert atmosphere, washing the roasted product after roasting to obtain cuprous oxide. According to the method, the coarse copper powder of the waste circuit board and the etching waste liquid are subjected to cooperative treatment, and harmless treatment and resource recycling of the two kinds of copper-containing waste are achieved at the same time.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology, and in particular relates to a method for the co-recycling of etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide. Background Technology

[0002] The rapid development of the printed circuit board (PCB) industry has led to a surge in PCB production. This process generates various copper-containing hazardous wastes, including etching wastewater and waste PCBs (waste copper-clad laminates). Direct discharge of these wastes severely pollutes the environment and wastes secondary copper resources. Typical etching wastewater is a high-copper, high-chlorine, and high-acid solution. Current recycling methods primarily involve alkali neutralization, multiple precipitation separations to remove impurities, and concentration and crystallization to produce copper sulfate or further calcination of basic copper carbonate to prepare copper oxide. However, these methods consume large amounts of reagents and have lengthy production processes. Waste PCBs or copper-clad laminate cutting scraps are often physically crushed and hydraulically screened to obtain coarse copper powder for direct sale, or further processed through wet leaching to extract copper resources. This process also suffers from long processes, high consumption of acid and alkali reagents, and low economic value. Therefore, developing a short-process, resource-efficient, synergistic recycling process for copper oxide powder materials is crucial for the harmless disposal and high-value utilization of etching wastewater and waste PCBs, offering significant environmental and economic benefits.

[0003] Patent document CN117902615A discloses a method for preparing octahedral cuprous oxide using PCB etching waste liquid. Specifically, it discloses mixing alkaline and acidic PCB etching waste liquids, adjusting the pH value, precipitating, filtering, and removing impurities. After impurity removal, the liquid is reduced by adding hydroxylamine hydrochloride solution. The solution is continuously stirred, heated, and air is continuously bubbled in. The precipitate is washed with ethanol and water, centrifuged, and vacuum dried to obtain octahedral cuprous oxide. Patent document CN120463229A discloses a method for preparing electronic-grade copper oxide using acidic PCB etching waste liquid. Specifically, it discloses removing impurities from the acidic PCB etching waste liquid, concentrating and crystallizing, performing a salt-alkali reaction, and washing to obtain crude copper hydroxide. The crude copper hydroxide is dissolved and recrystallized to obtain refined copper hydroxide. The refined copper hydroxide is dissolved and adsorbed in ammonia carbide water for further purification. The purified solution is spray-dried after adding surfactants and zinc salt additives to obtain modified basic copper carbonate. The modified basic copper carbonate is selectively etched with dilute acid and then calcined to obtain electronic-grade copper oxide powder. While the aforementioned methods yield cuprous oxide or electronic-grade copper oxide, they generally suffer from lengthy reaction processes and complex procedures. Patent document CN112139201A discloses a method for the resource recycling of waste circuit boards. Specifically, it involves crushing waste circuit boards into particles, mixing them with additives, and then subjecting them to anaerobic pyrolysis to obtain pyrolysis gas and solid products. The pyrolysis products are then sieved to obtain various coarse products such as copper foil, carbon powder, and glass cloth, which are subsequently further separated. Although this method achieves resource recovery of waste circuit boards, it does not yield fine chemical products; only coarse products are used, resulting in low economic efficiency. Therefore, there is a need to develop a method for the short-process co-recycling of etching waste liquid and waste circuit boards, and for the preparation of high-value material powders. 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 background art above, and to solve the problems of long process, large reagent consumption and low product added value of etching waste liquid and waste circuit board in the prior art. The present invention provides a short process, low cost and high value copper oxide preparation method for the co-recycling of etching waste liquid and coarse copper powder from waste circuit boards.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A method for co-recovering etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide includes the following steps: (1) Add the coarse copper powder from the waste circuit board and the leaching complexing agent to the etching waste liquid, stir and leach, filter and separate to obtain a copper chloride complex solution and waste resin residue; the leaching complexing agent is a water-soluble chloride salt; (2) Add a reducing agent to the copper chloride complex solution and dilute with water, then react and filter to obtain CuCl precipitate and acidic filtrate; the reducing agent is ascorbic acid; the solution maintains a high acidity throughout the leaching process. If alkali is added for neutralization, Cu will be lost as basic copper chloride precipitate (pH>3.5) and cannot be effectively separated from impurity metal ions. Therefore, the acidic reducing agent ascorbic acid is more effective. (3) The CuCl precipitate is mixed evenly with the auxiliary dechlorination salt and roasted under controlled atmosphere. The roasting product is washed to obtain copper oxide or cuprous oxide. The auxiliary dechlorination salt is at least one of sodium carbonate, sodium bicarbonate and sodium hydroxide. When the roasting atmosphere is an oxidizing atmosphere, the roasting product is washed with water after roasting to obtain copper oxide. When the roasting atmosphere is an inert atmosphere, the roasting product is washed with water after roasting to obtain cuprous oxide.

[0006] In the above-mentioned method for co-recovering copper oxide from etching waste liquid and crude copper powder from waste circuit boards, preferably, in step (1), the water-soluble chloride salt is selected from at least one of sodium chloride, potassium chloride, and magnesium chloride, and the amount of water-soluble chloride salt added is controlled to ensure that the molar ratio of chloride to copper ions in the leaching system is not less than 2.5. The addition of water-soluble chloride salt increases the chloride ion concentration in the leaching system, and the chloride ions complex with the cuprous ions in the leaching system to form cuprous polychloride ions, thus avoiding the precipitation of CuCl and insufficient separation of waste resin and copper.

[0007] In the above-mentioned method for co-recovering copper oxide from etching waste liquid and coarse copper powder from waste circuit boards, preferably, in step (1), the leaching temperature is 40-80 ℃, the liquid-to-solid ratio in the leaching process is 10-50, the ratio unit is mL / g, and the leaching time is 0.5-2 h. Within the leaching temperature and time range of the present invention, effective copper leaching can be achieved. If the leaching temperature is too low, the copper leaching reaction will be slow, affecting the leaching rate, and the copper-chlorine complexation effect will be weakened, making CuCl easy to precipitate; if the leaching temperature is too high, the energy consumption of the reaction process will be increased. If the leaching time is too long, it will affect production efficiency; if the leaching time is too short, it will lead to incomplete copper leaching.

[0008] In the above-mentioned method for co-recovering copper oxide from etching waste liquid and crude copper powder from waste circuit boards, preferably, in step (2), the molar ratio of ascorbic acid to divalent copper ions in the copper chloride complex solution is (0.5-1.2):1, the reaction time is 0.5-1 h, and the reaction temperature is room temperature. If the amount of reducing agent ascorbic acid is insufficient, it will lead to an increase in Cu in the solution. 2+ Incomplete reduction or excessive use of reducing agent will increase reagent costs.

[0009] In the above-mentioned method for co-recovering copper oxide from etching waste liquid and crude copper powder from waste circuit boards, preferably, in step (2), the copper chloride complex solution is diluted 2-5 times with deionized water. When the dilution ratio is low or not diluted, the cuprous polychloride ions do not fully disintegrate and are difficult to fully convert into CuCl precipitate. If the dilution ratio is too high, the amount of wastewater to be treated will increase.

[0010] In the above-mentioned method for co-recycling copper oxides from etching waste liquid and coarse copper powder from waste circuit boards, preferably, in step (3), the molar ratio of sodium ions in the auxiliary dechlorination salt to chloride ions in CuCl is (1-2):1.

[0011] In the above-mentioned method for co-recycling copper oxides from etching waste liquid and coarse copper powder from waste circuit boards, preferably, in step (3), the calcination temperature is 300-500 ℃ and the calcination time is 1-3 h.

[0012] If the calcination temperature is too low or the amount of auxiliary dechlorination salt is insufficient, CuCl cannot be fully converted into copper oxide powder. If the temperature is too high or the amount of auxiliary dechlorination salt is increased, energy consumption and reagent costs will increase.

[0013] In the above-mentioned method for co-recycling copper oxides from etching waste liquid and coarse copper powder from waste circuit boards, preferably, in step (3), the product is controlled by adjusting the roasting atmosphere during the roasting process. When the roasting atmosphere is an oxidizing atmosphere such as oxygen or sufficient air, the roasted product is washed with water, filtered and dried to obtain copper oxide; when the roasting atmosphere is an inert atmosphere, the roasted product is washed with water, filtered and dried to obtain cuprous oxide.

[0014] In the above-mentioned method for co-recovering etching waste liquid and waste circuit board coarse copper powder to prepare copper oxide, preferably, the waste circuit board coarse copper powder is the crushed powder of the edge scraps from the circuit board production and processing process, without electronic components, and its main chemical composition includes copper > 60 wt%, main metallic impurity components Fe < 2 wt%, Zn < 2 wt%, Ni < 2 wt%, Al < 2 wt%.

[0015] In the above-mentioned method for co-recovering copper oxide from etching waste liquid and coarse copper powder from waste circuit boards, preferably, the etching waste liquid is a high-chlorine, copper-containing acidic etching waste liquid generated during the etching process of circuit board production and processing, with a pH value of -1.5 to 2, and its main chemical composition includes a copper content of 20 to 120 g / L, a chlorine content of 50 to 200 g / L, and main metallic impurities of Fe < 0.8 g / L, Zn < 0.5 g / L, Ni < 0.5 g / L, and Al < 0.5 g / L.

[0016] The chemical reactions that occur in each step of this invention include: (1) The crude copper powder from the waste circuit board undergoes a dissolution reaction and dissolves in the etching waste liquid with added complexing agent. Cuprous ions form cuprous polychloride complex ions under the complexing action of sufficient chloride ions and enter the solution. The waste resin enters the slag phase for separation. Cu + Cu 2+ + 2Cl - = 2CuCl↓ CuCl + nCl - = [CuCl n+1 ] n– 2Cu + O2 + 4H + = 2Cu 2+ + 2H2O 4[CuCl n+1 ] n- + 4H + +O2= 4Cu 2+ + (4n+4)Cl - + 2H2O (2) Add a reducing agent to the leaching solution containing cuprous polychloride complex ions to reduce the unreduced Cu in the leaching solution. 2+ And dilute to reduce Cl in the solution - The concentration of Cu makes it easier for Cu to precipitate as sparingly soluble CuCl, and filtration achieves deep separation from impurity elements such as Fe, Zn, Ni, and Al in the solution. 2Cu 2+ + 2Cl - + C6H8O6 = 2CuCl↓ + 2H + + C6H6O6 [CuCl n+1 ] n– = CuCl↓+ nCl - (3) After uniformly mixing CuCl with auxiliary dechlorination salts such as Na2CO3, calcining is carried out under an oxidizing or inert atmosphere to transform CuO and NaCl, or Cu2O and NaCl. The calcined product is washed with deionized water, filtered, precipitated, and dried to obtain copper oxide or cuprous oxide. 2CuCl + Na2CO3= Cu2O + 2NaCl + CO2↑ 4CuCl + 2Na2CO3+ O2= 4CuO + 4NaCl + 2CO2↑.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention co-processes waste circuit board crude copper powder and etching waste liquid, and simultaneously achieves the harmless disposal and resource recycling of two types of copper-containing waste. The metallic copper in the crude copper powder reacts with the divalent copper in the etching waste liquid to generate cuprous ions, which are then complexed with sufficient chloride ions and separated from the waste resin in the solution. The copper in the solution is mostly cuprous polychloride complex ions, which reduces the amount of reducing agent consumed in the subsequent reduction and decomplexing process and lowers the processing cost.

[0018] (2) This invention utilizes CuCl and cuprous polychloride ions ([CuCl... n+1 ] n– By controlling the process, selective extraction of Cu resources and one-step deep removal of impurity metal ions are achieved. Then, deep dechlorination is achieved through a simple process of low-temperature salt roasting and water washing. Therefore, the conventional long process of generating electronic-grade copper oxide from etching waste liquid through multiple precipitation, dissolution and impurity removal is greatly shortened and simplified, reducing reagent consumption, energy consumption and production costs, and improving production efficiency.

[0019] (3) The present invention can achieve deep dechlorination and simultaneous oxidation by controlling the roasting atmosphere during the CuCl salt-assisted roasting process. It can prepare two types of high-value copper oxide powder products: cuprous oxide or electronic-grade copper oxide powder. The process is flexible and adjustable, which can better meet market demand.

[0020] In summary, this invention co-processes etching waste liquid and crude copper powder from waste circuit boards, recovers cuprous chloride and prepares copper oxide powder by calcination. This enables the co-processing of etching waste liquid and crude copper powder from waste circuit boards, as well as the recovery of copper resources. It significantly shortens the impurity removal steps in current mainstream production processes, and has advantages such as low reagent consumption and low energy consumption. It can control the yield of cuprous oxide or electronic-grade copper oxide powder, with high product purity, good activity and dispersibility, meeting the requirements of corresponding products. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a process flow diagram of the co-recycling of etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide according to the present invention.

[0023] Figure 2 These are XRD diffraction patterns of the products obtained in various embodiments and comparative examples of the present invention. Detailed Implementation

[0024] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0027] The waste copper powder processed in the following examples and comparative examples is the crushed powder of the edge scraps from the circuit board manufacturing process, without electronic components. Its main chemical composition includes: Cu 87.91 wt%, Fe 0.50 wt%, Al 0.48 wt%, Zn 0.03 wt%, Ni 0.02 wt%. The main chemical composition of the etching waste liquid includes: Cu 40 g / L, Cl 150 g / L, Fe 140 mg / L, Zn 40 mg / L, Ni 30 mg / L, Al 20 mg / L, and pH value -1.18.

[0028] Example 1: A method for co-recovering etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide according to the present invention is shown in the process flow diagram below. Figure 1 As shown, the specific steps include: (1) 10 g of crude copper powder from waste circuit boards and 12.44 g of leaching complexing agent NaCl were added to 200 mL of etching waste liquid. The molar ratio of chloride to copper ions in the leaching system was controlled to be approximately 4:1. The mixture was then stirred and leached at 60 °C for 1 h. After filtration and separation, a copper chloride complex solution and waste resin powder residue were obtained. Cu in the copper chloride complex solution was detected. + With Cu 2+ The concentrations were 63.5 g / L and 21.5 g / L, respectively; (2) Add Cu to the copper chloride complex solution obtained in step (1) 2+ Add 0.9 molar amounts of ascorbic acid and stir. Simultaneously, dilute the copper chloride complex solution with 2 volumes of deionized water. React at room temperature for 1 hour. Filter and wash to separate CuCl precipitate and acidic filtrate. The Cu recovery rate was 98.5% by detection and calculation. The contents of Fe, Ni, Zn and Al in CuCl were all <0.001%. The wastewater was treated with alkali neutralization. (3) Take 10 g of CuCl precipitate obtained in step (2) and mix it with 5.35 g of Na2CO3 (sodium and chloride ion molar ratio of 1:1). Place the mixture in a tube furnace and calcine at 400 °C for 2 h. During the calcination process, introduce air atmosphere of 0.5 L / min into the tube furnace. Wash the calcined product with deionized water, filter the precipitate, and dry it to obtain copper oxide. The filtrate after filtration can replace part of the leaching complexing agent for recycling.

[0029] Example 2: A method for co-recovering etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide according to the present invention is shown in the process flow diagram below. Figure 1 As shown, the specific steps include: (1) 20 g of crude copper powder from waste circuit boards and 21.27 g of leaching complexing agent NaCl were added to 200 mL of etching waste liquid. The molar ratio of chloride to copper ions in the leaching system was controlled to be 3:1. The mixture was then stirred and leached at 60 °C for 1 h. After filtration and separation, a copper chloride complex solution and waste resin powder residue were obtained. Cu in the copper chloride complex solution was detected. + With Cu 2+ The concentrations were 92.9 g / L and 35.0 g / L, respectively; (2) Add Cu to the copper chloride complex solution obtained in step (1) 2+ Add 1 molar amount of ascorbic acid and stir. At the same time, dilute the copper chloride complex solution with 3 times the volume of deionized water. React at room temperature for 1 hour. Filter and wash to separate CuCl precipitate and acidic filtrate. The Cu recovery rate was 98.9% by detection and calculation. The contents of Fe, Ni, Zn and Al in CuCl were all <0.001%. The wastewater was treated with alkali neutralization. (3) Take 10 g of CuCl precipitate obtained in step (2) and mix it with 8 g of Na2CO3 (sodium and chloride ion molar ratio of 1.5:1). Place it in a tube furnace and calcine at 350℃ for 1 h. During the calcination process, introduce air atmosphere of 0.5 L / min into the tube furnace. Wash the calcined product with deionized water, filter the precipitate, dry it, and obtain copper oxide. The filtrate after filtration can replace part of the leaching complexing agent for recycling.

[0030] Example 3: A method for co-recovering etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide according to the present invention is shown in the process flow diagram below. Figure 1 As shown, the specific steps include: (1) 10 g of crude copper powder from waste circuit boards and 21.61 g of leaching complexing agent NaCl were added to 300 mL of etching waste liquid. The molar ratio of chloride to copper ions in the leaching system was controlled to be 5:1. The mixture was then stirred and leached at 80 °C for 1 h. After filtration and separation, a copper chloride complex solution and waste resin powder residue were obtained. Cu in the copper chloride complex solution was detected.+ With Cu 2+ The concentrations were 74.3 g / L and 53.2 g / L, respectively; (2) Add Cu to the copper chloride complex solution obtained in step (1) 2+ Add 0.7 molar amounts of ascorbic acid and stir. Simultaneously, dilute the copper chloride complex solution with 2 volumes of deionized water. React at room temperature for 1 hour. Filter and wash to separate CuCl precipitate and acidic filtrate. The Cu recovery rate was 98.1% by detection and calculation. The contents of Fe, Ni, Zn and Al in CuCl were all <0.001%. The wastewater was treated with alkali neutralization. (3) Take 10 g of CuCl precipitate obtained in step (2) and mix it with 8 g of Na2CO3 (sodium and chloride ion molar ratio of about 1.5:1). Place it in a tube furnace and calcine at 400℃ for 2 h. During the calcination process, introduce 0.5 L / min argon atmosphere into the tube furnace. Wash the calcined product with deionized water, filter the precipitate, and dry it to obtain cuprous oxide. The filtrate after filtration can replace part of the leaching complexing agent for recycling.

[0031] Comparative Example 1: The difference between this comparative example and Example 1 is that the leaching complexing agent NaCl will not be added in step (1). Everything else is the same as in Example 1. The results show that the copper in the crude copper powder cannot be fully leached, and the waste resin residue contains precipitated CuCl, which affects the separation and extraction of Cu.

[0032] Comparative Example 2: Three comparative experiments were conducted in this comparative example. The difference from Example 1 was that in step (2), ascorbic acid was replaced with an equimolar amount of sodium sulfite, sodium thiosulfate, or glucose, respectively. Other processes and parameters were the same as in Example 2. The results showed that when sodium sulfite, sodium thiosulfate, and glucose were used as reducing agents, the Cu recovery rates were only 25.6%, 33.2%, and 24.2%, respectively. This is because the above reducing agents cannot effectively exert their reducing effect under acidic conditions.

[0033] Comparative Example 3: The difference between this comparative example and Example 1 is that in step (2), the amount of ascorbic acid added is reduced to Cu. 2+ The copper chloride complex solution was diluted with 0.4 times the molar amount of deionized water, and the rest was the same as in Example 1. The results showed that the Cu recovery rate was 75.3%.

[0034] Comparative Example 4: The difference between this comparative example and Example 1 is that the deionized water dilution operation is omitted in step (2), while the rest is the same as Example 1. The results show that the Cu recovery rate is 30.5%.

[0035] Comparative Example 5: The difference between this comparative example and Example 2 is that in step (3), the roasting temperature is reduced to 250 °C. Other processes and parameters are the same as in Example 2. The results show that the product after roasting and washing with water is a mixture of copper oxide and basic copper chloride.

[0036] Comparative Example 6: The difference between this comparative example and Example 2 is that in step (3), the amount of sodium carbonate is reduced to adjust the molar ratio of sodium to chloride ions to about 0.75:1. Other processes and parameters are the same as in Example 2. The results show that the product after calcination and washing with water is a mixture of copper oxide and basic copper chloride.

[0037] Comparative Example 7: The difference between this comparative example and Example 2 is that in step (3), the roasting temperature is reduced to 200°C. Other processes and parameters are the same as in Example 2. The results show that the product after roasting and washing with water is a mixture of cuprous chloride, cuprous oxide and basic copper chloride.

[0038] Comparative Example 8: Treatment of etching waste liquid (traditional method): Take 300 mL of etching waste liquid, add 2.5 g of sodium chlorate (0.75 times the theoretical molar amount of copper content in the etching waste liquid) to fully oxidize and remove cuprous ions. Then, add 50% sodium hydroxide solution to adjust the pH to 5 to precipitate basic copper chloride. The basic copper chloride is washed with 20% ammonia water (20% ammonia water:basic copper chloride mass ratio of 1.2) for 1 h to obtain copper hydroxide. The copper hydroxide is washed with an equal mass of deionized water, filtered, dried at 70℃, and calcined in a muffle furnace at 400℃ for 2 h to obtain copper oxide. The results show that the copper recovery rate is only about 80%, and the purity of copper oxide is 98.21%, which is difficult to meet the requirements of electronic-grade copper oxide powder.

[0039] Treatment of crude copper powder from waste circuit boards (traditional solution): Because crude copper powder from waste circuit boards has poor acid solubility, it needs to be leached in a high acid and strong oxidant environment. Currently, it is often directly treated as enriched copper material and smelted by fire according to the copper smelting process. The recycling process is long, so no corresponding comparison was made.

[0040] The products obtained in Examples 1-3 and Comparative Examples 1-8 were analyzed to determine the phase composition and CuO purity. The results are as follows: Figure 2 As shown in Table 1.

[0041] Table 1. Phase composition and purity of the products from each example and comparative example.

[0042] As shown in Table 1, the CuO or Cu2O content of the products prepared in Examples 1-3 and Comparative Examples 1-4 of this invention is >99 wt%, and the impurity content is extremely low, meeting the purity requirements of electronic-grade copper oxide powder or industrial cuprous oxide.

[0043] The comparison of Example 1 and Comparative Examples 1 to 4 shows that when the amount of leaching complexing agent NaCl is insufficient, the copper in the crude copper powder cannot be fully leached, and CuCl easily precipitates into the waste resin residue, affecting the separation and extraction of Cu. When the reducing agent is replaced with sodium sulfite, sodium thiosulfate, or glucose, or when the amount of ascorbic acid added as the reducing agent is insufficient or the dilution ratio with deionized water is low, the Cu extraction rate also decreases.

[0044] The comparison of Example 2, Comparative Example 5 and Comparative Example 6 shows that when the calcination temperature is too low or the amount of sodium carbonate added is insufficient, it is difficult to achieve a full conversion of CuCl to CuO phase, and the dechlorination transformation is incomplete.

[0045] As can be seen from the comparison between Example 3 and Comparative Example 7, Cu2O can be obtained by calcination in an inert atmosphere followed by water washing. However, when the calcination temperature is low, it is also impossible to achieve a full transformation of CuCl into the target phase.

[0046] As can be seen from the comparison between Example 3 and Comparative Example 8, this method has significant advantages over traditional etching waste liquid treatment processes in terms of shortening the treatment process, reducing reagent input, copper recovery rate, and copper oxide purity. At the same time, it co-processes coarse copper powder from waste circuit boards, which can reduce carbon emissions during processing compared to pyrometallurgical smelting processes and produce high-value products.

Claims

1. A method for the co-recovery of etching waste liquid and crude copper powder from waste circuit boards to prepare copper oxide, characterized in that, The method comprises the following steps: (1) adding waste circuit board crude copper powder and leaching complexing agent into etching waste liquid to stir and leach, and then filtering and separating to obtain copper chloride complex solution and waste resin residue; the leaching complexing agent is a water-soluble chlorine salt; (2) adding a reducing agent into the copper chloride complex solution and diluting with water, and then performing reaction, filtering and separating to obtain CuCl precipitate and acidic filtrate; the reducing agent is ascorbic acid; (3) uniformly mixing the CuCl precipitate with an auxiliary dechlorination salt, and then performing controlled atmosphere roasting, and then washing the roasting product to obtain copper oxide or cuprous oxide; the auxiliary dechlorination salt is at least one of sodium carbonate, sodium bicarbonate and sodium hydroxide; when the roasting atmosphere is an oxidizing atmosphere, the roasting product is washed with water after roasting to obtain copper oxide; when the roasting atmosphere is an inert atmosphere, the roasting product is washed with water after roasting to obtain cuprous oxide.

2. The method for the preparation of copper oxide from etching waste solution and waste circuit board copper powder according to claim 1, wherein, In step (1), the water-soluble chlorine salt is at least one of sodium chloride, potassium chloride and magnesium chloride, and the addition amount of the water-soluble chlorine salt is controlled to be not less than 2.5 in terms of the molar ratio of chlorine to copper ions in the leaching system. ​ 3. The method for the synergic recovery of copper oxides from etching waste solutions and waste circuit board copper powder according to claim 1, characterized in that, In step (1), the leaching temperature is 40-80 ℃, the liquid-solid ratio of the leaching process is 10-50 (mL / g), and the leaching time is 0.5-2 h.

4. The method for the preparation of copper oxide from etching waste solution and waste circuit board copper powder according to claim 1, characterized in that, In step (2), the molar ratio of ascorbic acid to divalent copper ions in the copper chloride complex solution is (0.5-1.2):1, the reaction time is 0.5-1 h, and the reaction temperature is room temperature.

5. The method for co-recovering and preparing copper oxide from etching waste liquid and crude copper powder from waste circuit boards as described in claim 1, characterized in that, In step (2), the copper chloride complex solution is diluted with deionized water by 2-5 times.

6. The method for co-recovering and preparing copper oxide from etching waste liquid and crude copper powder from waste circuit boards as described in claim 1, characterized in that, In step (3), the molar ratio of sodium ions in the auxiliary dechlorination salt to chlorine ions in CuCl is (1-2):

1.

7. The method for co-recovering and preparing copper oxide from etching waste liquid and crude copper powder from waste circuit boards as described in claim 1, characterized in that, In step (3), the roasting temperature is 300-500 ℃, and the roasting time is 1-3 h.

8. The method for co-recovering and preparing copper oxide from etching waste liquid and crude copper powder from waste circuit boards as described in claim 1, characterized in that, The waste circuit board crude copper powder is a frame and corner crushed powder in the production and processing process of circuit boards, and does not contain electronic components, and the main chemical components thereof include copper > 60 wt%, main metal impurities Fe < 2 wt%, Zn < 2 wt%, Ni < 2 wt% and Al < 2 wt%.

9. The method for co-recovering and preparing copper oxide from etching waste liquid and crude copper powder from waste circuit boards as described in claim 1, characterized in that, The etching waste liquid is a high-chlorine copper-containing acidic etching waste liquid generated in the etching process of circuit board production and processing, and has a pH value of -1.5-2, and the main chemical components thereof include copper content of 20-120 g / L, chlorine content of 50-200 g / L, main metal impurities Fe < 0.8 g / L, Zn < 0.5 g / L, Ni < 0.5 g / L and Al < 0.5 g / L.

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