Method for resource utilization of copper-containing waste etching solution and production of high-purity copper hydroxide

Abstract

The invention discloses a method for resource utilization of copper-containing waste etching liquid and production of high-purity copper hydroxide, and belongs to the field of green cyclic recycling of copper-containing waste liquid. The method for preparing the high-purity copper hydroxide by using the copper-containing etching waste liquid comprises the following steps: mixing the copper-containing etching waste liquid with a crystal form inducer solution, adjusting the pH value to 3.0-8.0, then reacting, carrying out solid-liquid separation to obtain a solid-phase separated substance and filtrate, and carrying out aging treatment on the solid-phase separated substance to obtain a basic copper chloride precipitate; and adding ammonia water and a crystal form transforming agent into the basic copper chloride precipitate, then carrying out aging treatment, and carrying out solid-liquid separation to obtain the high-purity copper hydroxide powder. The prepared copper chloride hydroxide and copper hydroxide powder are large in particle size, the average particle size of the copper chloride hydroxide collection substance is 20-200 microns, and the average particle size of the copper hydroxide powder is 10-100 microns.

Description

Technical Field

[0001] This invention relates to the field of green recycling and reuse of copper-containing waste liquid, and in particular to a method for the resource utilization of copper-containing etching waste liquid and the production of high-purity copper hydroxide. Background Technology

[0002] Etching solutions, as crucial chemical materials, are essential in numerous fields, including electronics, semiconductors, printed circuit boards (PCBs), and metal processing. The PCB industry is a major source of copper-containing etching wastewater, which is highly hazardous to the environment and rich in copper ions. If this wastewater is discharged into water bodies or soil without proper treatment, it will cause serious environmental pollution. Furthermore, direct discharge of copper-containing etching solutions also results in a significant waste of copper resources. Therefore, developing utilization pathways for copper-containing etching wastewater, such as using it to produce copper products, is of great importance for environmental protection and the sustainable use of copper resources.

[0003] In the prior art, CN111333099A discloses a method for preparing nano-copper hydroxide by directly reacting acidic copper chloride etching waste liquid with a precipitant. The prepared copper hydroxide has a fibrous morphology with an average diameter between 40-100 nm and an average length between 1-2.5 μm. CN110342565A provides a method for preparing diatomaceous earth-based nano-copper hydroxide by directly reacting an alkaline precipitant with an acidic etching solution. The obtained product has a purity of 93.6% and a particle size of 45 nm after vacuum drying. CN110422872A provides a method for preparing copper hydroxide from an alkaline etching solution. The preparation process requires first converting the alkaline etching solution into copper sulfate, then into a tetraammonium hydroxide copper complex solution, and finally obtaining amorphous nano-powder copper hydroxide by evaporating ammonia. The average particle size of the obtained copper hydroxide powder is 46 nm. Although the above patents have prepared copper hydroxide using etching waste liquid, they still have limitations such as harsh product separation and drying conditions, small product particle size, low purity, and complex process flow. They are still difficult to meet the needs of large-scale industrial treatment of etching waste liquid and need further improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the resource utilization of copper-containing etching waste liquid and the production of high-purity copper hydroxide, thereby solving the aforementioned problems in the background art. The basic copper chloride and copper hydroxide powders prepared by this invention have relatively large particle sizes, with the average particle size of the basic copper chloride collection being 20-200 μm and the average particle size of the copper hydroxide powder being 10-100 μm. Therefore, the prepared basic copper chloride and copper hydroxide can be easily separated in a solution system, and washing is simple and rapid, saving significant time and water resources.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid is provided, comprising the following steps: (1) Mix copper-containing etching waste liquid with crystal inducing agent solution, adjust pH value to 3.0-8.0, then react, and separate solid and liquid to obtain solid phase and filtrate. Then, age the solid phase to obtain basic copper chloride precipitate. (2) Add ammonia and crystal conversion agent to the basic copper chloride precipitate, then age it, and separate the solid and liquid to obtain the high-purity copper hydroxide powder.

[0006] Preferably, the crystal form inducing agent in the crystal form inducing agent solution is one or more of sodium chloride, potassium chloride, and ammonium chloride.

[0007] Preferably, the amount of crystal form inducer added to the crystal form inducer solution is 0.1-8 wt% of the copper-containing etching waste liquid; the amount of solvent added to the crystal form inducer solution is 5-100 wt% of the copper-containing etching waste liquid.

[0008] More preferably, the solvent of the crystal form inducing agent solution comprises one or more of the following: the filtrate after solid-liquid separation in step (1), the filtrate after solid-liquid separation in step (2), and water.

[0009] The filtrate obtained in steps (1) and (2) of this invention can also be used as a solvent for crystal inducing agents to achieve water recycling.

[0010] Preferably, the crystal form inducing agent solution is prepared by raising the solvent temperature to 50-90℃, then adding the crystal form inducing agent, and stirring for 10-100 min to obtain the crystal form inducing agent solution.

[0011] Preferably, in step (1): the reaction time is 10-200 min; the aging treatment temperature is 20-60℃ and the time is 1-50 h.

[0012] Preferably, the amount of ammonia added is 40-200 wt% of the basic copper chloride precipitate; and the concentration of the ammonia is 20-29 wt%.

[0013] Preferably, the crystal form conversion agent is one or more of polyacrylamide, polyvinylpyrrolidone, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium aluminosilicate, crystalline cellulose, potassium ferrocyanide, lignin, and talc; the amount of the crystal form conversion agent added is 0.01-1 wt% of the basic copper chloride precipitate.

[0014] Preferably, in step (2), the aging treatment time is 10-200 min.

[0015] Preferably, the copper-containing etching waste liquid comprises acidic copper-containing etching waste liquid and / or alkaline copper-containing etching waste liquid; the copper content of the copper-containing etching waste liquid is ≥20g / L.

[0016] Preferably, the copper-containing etching waste liquid is one of the following: a mixture of acidic copper-containing etching waste liquid and ammonia, a mixture of alkaline copper-containing etching waste liquid and hydrochloric acid, or a mixture of acidic and alkaline copper-containing etching waste liquid.

[0017] Preferably, the high-purity copper hydroxide powder is a polycrystalline secondary particle with a copper hydroxide content (calculated as Cu(OH)2) ≥98wt% and an average particle size of 10-100μm.

[0018] Preferably, the basic copper chloride precipitate has a monoclinic crystal system with a regular hexagonal prism structure.

[0019] The crystal form inducer added in this invention can induce the prepared basic copper chloride to form a regular hexagonal monoclinic crystal system through a seed crystal induction effect. This crystal form has a high copper content and high thermal stability, making it an ideal crystal form for the production process of this invention. Furthermore, by forming a monoclinic basic copper chloride intermediate, the precipitation of impurity ions in copper-containing wastewater is avoided, thus ensuring that the final product, copper hydroxide, has an extremely high copper content.

[0020] The crystal conversion agent in this invention can function in the strongly alkaline environment of ammonia water, assisting ammonia water in the complete conversion of basic copper chloride to copper hydroxide, thereby reducing the chlorine content in the product and increasing the copper content of the copper hydroxide product. Furthermore, the added crystal conversion agent can aggregate copper hydroxide crystals into secondary particles through methods such as trapping, entanglement, bridging, and adsorption, promoting the separation and washing efficiency of copper hydroxide precipitate, improving the thermal stability of copper hydroxide, and inhibiting the oxidation of copper hydroxide during the drying process.

[0021] The beneficial technical effects of the present invention are as follows: 1. The basic copper chloride and copper hydroxide powders prepared by this invention have relatively large particle sizes, with the average particle size of the basic copper chloride collection being 20-200 μm and the average particle size of the copper hydroxide powder being 10-100 μm. Therefore, the prepared basic copper chloride and copper hydroxide can be easily separated in the solution system, and the washing is simple and fast, which can save a lot of time and water resources. Moreover, the technical solution of this invention has a copper recovery rate of over 95% in etching waste liquid.

[0022] 2. The basic copper chloride and copper hydroxide prepared by this invention contain fewer impurities, have a loose structure, good thermal stability, and are very easy to dry. They are not easily oxidized to copper oxide or cuprous oxide during the drying process. The obtained basic copper chloride and copper hydroxide have high purity, wherein the basic copper chloride (with Cu...) 2+The content of copper hydroxide (calculated as Cu(OH)2) is not less than 58 wt%, and the content of copper hydroxide (calculated as Cu(OH)2) is not less than 98 wt%, which can be used directly as a feed additive.

[0023] 3. This invention designs a method for the resource utilization of copper-containing etching waste liquid and the production of high-purity copper hydroxide. It can utilize both acidic and alkaline copper-containing etching waste liquid. The filtrate generated in the process can be recycled. Furthermore, the copper hydroxide preparation process is simple and easy to operate, and the equipment used is conventional and common. Therefore, the technical solution of this invention has the characteristics of good economy, high efficiency, green and low carbon, and suitability for industrial application. It helps to promote the resource utilization, reduction, high-value recycling and regeneration of copper-containing etching waste liquid. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the 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.

[0025] Figure 1 This is a schematic diagram of the process for preparing high-purity copper hydroxide using copper-containing etching waste liquid according to the present invention.

[0026] Figure 2 This is a macroscopic photograph of the high-purity copper hydroxide prepared in Example 6.

[0027] Figure 3 The image shows the XRD pattern of basic copper chloride prepared in Example 7.

[0028] Figure 4 The image shows a SEM image of the basic copper chloride prepared in Example 7. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0030] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.

[0032] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0033] This invention discloses a method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Mix copper-containing etching waste liquid with crystal inducing agent solution, adjust pH value to 3.0-8.0, and then react for 10-200 min; after the reaction, use centrifuge or filter press to separate solid and liquid, wash the solid phase separation with water 1-4 times, and then age at 20-60℃ for 1-50 h to obtain basic copper chloride precipitate; (2) Add ammonia and crystal conversion agent to the basic copper chloride precipitate, and then age for 10-200 min to completely convert the basic copper chloride intermediate into copper hydroxide precipitate; use a centrifuge or filter press to separate the solid and liquid, separate the formed copper hydroxide precipitate, wash the precipitate with water 1-3 times, and dry it at 30-80℃ for 1-50 h to obtain blue high-purity copper hydroxide powder.

[0034] Furthermore, the crystal form inducing agent in the crystal form inducing agent solution is one or more of sodium chloride, potassium chloride, and ammonium chloride.

[0035] Furthermore, the amount of crystal form inducer added to the crystal form inducer solution is 0.1-8 wt% of the copper-containing etching waste liquid.

[0036] Furthermore, the amount of solvent added to the crystal form inducing agent solution is 5-100 wt% of the copper-containing etching waste liquid.

[0037] Furthermore, the solvent in the crystal form inducing agent solution comprises one or more of the following: the filtrate after solid-liquid separation in step (1), the filtrate after solid-liquid separation in step (2), and water.

[0038] Furthermore, the crystal form inducing agent solution is prepared by raising the solvent temperature to 50-90℃, then adding the crystal form inducing agent, and stirring for 10-100 min to obtain the crystal form inducing agent solution.

[0039] Furthermore, the amount of ammonia added is 40-200 wt% of the basic copper chloride precipitate; the concentration of the ammonia is 20-29 wt%.

[0040] Further, the crystal form conversion agent is one or more of polyacrylamide, polyvinylpyrrolidone, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium aluminosilicate, crystalline cellulose, potassium ferrocyanide, lignin and talc; the amount of the crystal form conversion agent added is 0.01-1 wt% of the basic copper chloride precipitate.

[0041] Furthermore, the basic copper chloride precipitate has a monoclinic crystal system with a regular hexagonal prism structure.

[0042] Furthermore, the high-purity copper hydroxide powder is a polycrystalline secondary particle with a copper hydroxide content (calculated as Cu(OH)2) ≥98wt% and an average particle size of 10-100μm.

[0043] Unless otherwise specified, "room temperature" in this invention refers to 10-30°C.

[0044] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0045] Example 1 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 50 kg of mother liquor to the reactor, heat to 60°C, then add 0.8 kg of potassium chloride and stir for 10 min to dissolve it completely to obtain a crystal inducing agent solution; (2) 450 kg of acidic copper-containing etching waste liquid and 350 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of etching waste liquid, the pH of the solution was adjusted to 4.4-4.6. After the reaction continued for 60 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water once and then aged at 40°C for 10 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 50 kg of ammonia water and 20 g of nonionic polyacrylamide with a molecular weight of 7 million at room temperature, and age the precipitate for 50 min at room temperature to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids three times with water and then dry them in an oven at 60°C for 10 hours to obtain blue high-purity copper hydroxide powder.

[0046] Example 2 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 50 kg of mother liquor and 30 kg of water to the reaction vessel, heat to 50°C, then add 0.8 kg of sodium chloride and stir for 30 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 500 kg of acidic copper-containing etching waste liquid and 300 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of etching waste liquid, the pH of the solution was adjusted to 3.9-4.1. After the reaction was continued for 200 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then age them at 25°C for 20 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 80 kg of ammonia water and 500 g of 12 million molecular weight anionic polyacrylamide at room temperature, and age the mixture at room temperature for 10 min to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids three times with water and then dry them in an oven at 40°C for 10 hours to obtain high-purity copper hydroxide powder.

[0047] Example 3 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of mother liquor to the reactor, heat to 70°C, then add 0.8 kg of ammonium chloride and stir for 20 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 550 kg of acidic copper-containing etching waste liquid and 250 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of etching waste liquid, the pH of the solution was adjusted to 3.4-3.6. After the reaction was continued for 30 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water three times and then aged at 50°C for 2 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 100 kg of ammonia water and 200 g of 15 million molecular weight anionic polyacrylamide at room temperature, and age the mixture at room temperature for 80 min to obtain a reaction solution containing copper hydroxide. (5) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water three times and then dried in an oven at 70°C for 15 hours to obtain high-purity copper hydroxide powder.

[0048] Example 4 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of mother liquor to the reactor, heat to 80°C, then add 5 kg of ammonium chloride and stir for 80 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 600 kg of acidic copper-containing etching waste liquid and 200 kg of ammonia water were added to the crystal inducing agent solution. During the addition of the etching waste liquid, the pH of the solution was adjusted to 4.9-5.1. After the reaction continued for 60 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water three times and then aged at 60°C for 2 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 120 kg of ammonia water and 500 g of polyvinylpyrrolidone at room temperature, and age it at room temperature for 100 min to obtain a reaction solution containing copper hydroxide. (5) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water three times and then dried in an oven at 80°C for 10 hours to obtain high-purity copper hydroxide powder.

[0049] Example 5 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 150 kg of mother liquor to the reactor, heat to 90°C, then add 5 kg of potassium chloride and stir for 100 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 550 kg of acidic copper-containing etching waste liquid and 250 kg of ammonia water were added to the crystal inducing agent solution. During the addition of the etching waste liquid, the pH of the solution was adjusted to 5.4-5.6. After the reaction was continued for 100 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then age them at 30°C for 50 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 150 kg of ammonia water and 800 g of sodium dodecyl sulfonate at room temperature, and after aging reaction at room temperature for 50 min, a reaction solution containing copper hydroxide is obtained. (5) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water 4 times and then dried in an oven at 50°C for 20 hours to obtain high-purity copper hydroxide powder.

[0050] Example 6 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 150 kg of mother liquor to the reaction vessel, heat to 90°C, then add 5 kg of sodium chloride and stir for 100 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 300 kg of acidic copper-containing etching waste liquid and 500 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of etching waste liquid, the pH of the solution was adjusted to 6.0-6.1. After the reaction was continued for 150 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids once with water and then age them at 40°C for 30 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 200 kg of ammonia water and 500 g of sodium aluminosilicate at room temperature, and age it at room temperature for 100 min to obtain a reaction solution containing copper hydroxide. (5) Solid-liquid separation is carried out using a plate and frame filter press to obtain solid phase and filtrate (filtrate is recovered and used as mother liquor). The solid phase is washed with water 4 times and then dried in an oven at 50°C for 20 hours to obtain high-purity copper hydroxide powder.

[0051] Example 7 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 150 kg of mother liquor to the reactor, heat to 50°C, then add 7 kg of sodium chloride and stir for 100 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 250 kg of acidic copper-containing etching waste liquid and 550 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of etching waste liquid, the pH of the solution was adjusted to 6.4-6.6. After the reaction was continued for 200 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids once with water and then age them at 40°C for 50 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 40 kg of ammonia water and 100 g of lignin at room temperature, and age the precipitate at room temperature for 150 min to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids once with water and then dry them in an oven at 70°C for 30 hours to obtain high-purity copper hydroxide powder.

[0052] Example 8 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of mother liquor to the reaction vessel, heat to 50°C, then add 2 kg of sodium chloride and stir for 20 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 200 kg of hydrochloric acid solution and 600 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of the etching waste liquid, the pH of the solution was adjusted to 7.0-7.1. After the reaction continued for 80 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then age them at 40°C for 10 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 100 kg of ammonia water and 150 g of crystalline cellulose at room temperature, and age the precipitate at room temperature for 50 min to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then dry them in an oven at 80°C for 20 hours to obtain high-purity copper hydroxide powder.

[0053] Example 9 A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of water to the reactor, heat to 60°C, then add 2 kg of ammonium chloride and stir for 30 min to dissolve it completely to obtain a crystal inducing agent solution; (2) 150 kg of hydrochloric acid solution and 650 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of the etching waste liquid, the pH of the solution was adjusted to 7.4-7.6. After the reaction continued for 60 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then age them at 40°C for 20 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 60 kg of ammonia water and 400 g of potassium ferrocyanide at room temperature, and age the precipitate at room temperature for 200 min to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids three times with water and then dry them in an oven at 80°C for 5 hours to obtain high-purity copper hydroxide powder.

[0054] Comparative Example 1 (Omitted crystal form conversion agent) A method for preparing copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of mother liquor to the reactor, heat to 60°C, then add 2 kg of ammonium chloride and stir for 30 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 200 kg of hydrochloric acid solution and 600 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. The pH of the solution was kept stable at 7.0 during the addition of the etching waste liquid. After the reaction was continued for 100 min, a reaction solution containing basic copper chloride precipitate was obtained. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids twice with water and then age them at 40°C for 20 hours to obtain basic copper chloride precipitate. (4) Take 100 kg of aged basic copper chloride precipitate, add 60 kg of ammonia water at room temperature, and age the precipitate at room temperature for 100 min to obtain a reaction solution containing copper hydroxide. (5) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids three times with water and then dry them in an oven at 80°C for 5 hours to obtain copper hydroxide powder.

[0055] Comparative Example 2 (one-step method, lacking the intermediate step of basic copper chloride) A method for preparing copper hydroxide using copper-containing etching waste liquid, comprising the following steps: (1) Add 100 kg of mother liquor to the reactor, heat to 60°C, then add 2 kg of ammonium chloride and stir for 30 min to completely dissolve it to obtain a crystal inducing agent solution; (2) 50 kg of hydrochloric acid solution and 750 kg of alkaline copper-containing etching waste liquid were added to the crystal inducing agent solution. During the addition of the etching waste liquid, the pH of the solution was stabilized at 13.0. 400 g of potassium ferrocyanide was added and the reaction was continued for 120 min to directly form a reaction solution containing copper hydroxide precipitate. (3) Use a centrifuge to separate solids and liquids to obtain solids and filtrate (the filtrate is recovered and used as mother liquor). Wash the solids three times with water and then dry them in an oven at 80°C for 5 hours to obtain copper hydroxide powder.

[0056] Effect verification The particle size of the copper hydroxide powder obtained in the above embodiments and comparative examples was determined by scanning electron microscopy, and the copper content and copper recovery rate were determined by inductively coupled plasma atomic emission spectrometry. The specific results are shown in Table 1.

[0057] Table 1. Results of particle size and copper content determination of copper hydroxide powder Table 1 shows that pH value, crystal form conversion agent, and the intermediate step of basic copper chloride are the main factors affecting the copper hydroxide product. According to Comparative Examples 1 and 2, the copper content of the copper hydroxide product prepared without a crystal form conversion agent (Comparative Example 1) or without the intermediate step of basic copper chloride (Comparative Example 2) is lower than 98%. Furthermore, due to the small particle size and difficulty in separation, the copper recovery rate from the etching solution in Comparative Examples 1 and 2 is also low. All embodiments of this invention yielded high-purity copper hydroxide powder with high particle size; in contrast, the copper hydroxide powder obtained in Examples 4-9 with a pH of 4.9-7.6 had a relatively larger grain size and a relatively higher copper content.

[0058] Figure 1 This is a schematic diagram of the process for preparing high-purity copper hydroxide using copper-containing etching waste liquid according to the present invention.

[0059] Figure 2 This is a macroscopic photograph of the high-purity copper hydroxide prepared in Example 6.

[0060] Figure 3 The image shows the XRD pattern of basic copper chloride prepared in Example 7.

[0061] Figure 4 The image shows a SEM image of the basic copper chloride prepared in Example 7.

[0062] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing high-purity copper hydroxide using copper-containing etching waste liquid, characterized in that, The method comprises the following steps: (1) mixing copper-containing etching waste liquid with a crystal form inducing agent solution, adjusting the pH value to 3.0-8.0, then reacting, solid-liquid separation to obtain a solid-phase separation and a filtrate, and then aging treatment of the solid-phase separation to obtain a basic copper chloride precipitate; (2) adding ammonia water and a crystal form conversion agent to the basic copper chloride precipitate, then aging treatment, solid-liquid separation to obtain the high-purity copper hydroxide powder.

2. The method of claim 1, wherein, The crystal form inducing agent in the crystal form inducing agent solution is one or more of sodium chloride, potassium chloride and ammonium chloride.

3. The method of claim 1, wherein, The addition amount of the crystal form inducing agent in the crystal form inducing agent solution is 0.1-8wt% of the copper-containing etching waste liquid; and the addition amount of the solvent in the crystal form inducing agent solution is 5-100wt% of the copper-containing etching waste liquid.

4. The method of claim 3, wherein, The preparation method of the crystal form inducing agent solution is: increasing the temperature of the solvent to 50-90℃, then adding the crystal form inducing agent, and stirring for 10-100min to obtain the crystal form inducing agent solution; and the solvent of the crystal form inducing agent solution comprises one or more of the filtrate after the solid-liquid separation in step (1), the filtrate after the solid-liquid separation in step (2) and water.

5. The method of claim 1, wherein, In step (1), the reaction time is 10-200min; and the aging treatment temperature is 20-60℃ and the time is 1-50h.

6. The method of claim 1, wherein, The addition amount of the ammonia water is 40-200wt% of the basic copper chloride precipitate; and the concentration of the ammonia water is 20-29wt%.

7. The method of claim 1, wherein, The crystal form conversion agent is one or more of polyacrylamide, polyvinylpyrrolidone, sodium dodecyl sulfonate, sodium dodecyl sulfate, sodium aluminosilicate, crystalline cellulose, potassium ferrocyanide, lignin and talc powder; and the addition amount of the crystal form conversion agent is 0.01-1wt% of the basic copper chloride precipitate.

8. The method of claim 1, wherein, In step (2), the aging treatment time is 10-200min.

9. The method of claim 1, wherein, The copper-containing etching waste liquid comprises acidic copper-containing etching waste liquid and / or alkaline copper-containing etching waste liquid; and the copper content of the copper-containing etching waste liquid is ≥20g / L.

10. The method of claim 1, wherein, The high-purity copper hydroxide powder is a polycrystalline secondary particle, the copper hydroxide content is ≥98wt%, and the average particle size is 10-100μm.

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