Method for recovering copper from copper-containing solid waste and preparing cuprous chloride

Abstract

The invention relates to the technical field of solid waste treatment, in particular to a method for recovering copper from copper-containing solid waste and preparing cuprous chloride, which comprises the following steps: (1) taking the copper-containing solid waste residue, and dissolving by using an acid solution; (2) adjusting the pH value of the copper-containing solution obtained in the step (1) to 3-3.5 by using an adjusting agent, and carrying out an adjusting reaction; (3) extracting by using an extracting agent and a stripping agent; and (4) adding an additive, a reducing agent and a template agent to obtain a mixture, reacting the mixture for 5-8 hours under the condition that the pH value is equal to 2-2.5, after the reaction is finished, carrying out solid-liquid separation to obtain a white solid, and rinsing and drying the white solid to obtain cuprous chloride. According to the method provided by the invention, the purity of the prepared cuprous chloride can reach 99% through a multi-step impurity removal process, the problems of more impurities and low purity of a traditional process product are solved, and the strict requirement of the high-end field on the purity of the cuprous chloride is met.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a method for recovering copper from copper-containing solid waste and preparing cuprous chloride. Background Art

[0002] In today's industrial landscape, with the continued expansion of copper-containing product production and processing, the amount of copper-containing solid waste generated is growing rapidly, making its efficient treatment and resource recovery a critical issue that needs to be addressed. Cuprous chloride, a key inorganic compound widely used in industries such as organic synthesis, petrochemicals, electroplating, and metallurgy, is experiencing steady market demand. Traditional cuprous chloride preparation processes primarily include hydrolysis precipitation, waste copper oxidation, and solvothermal reduction.

[0003] The hydrolysis precipitation method typically dissolves waste copper oxide in a mixture of hydrochloric acid and sodium chloride, then adds a reducing agent such as oxalic acid and copper powder to generate H[CuCl2] and Na[CuCl2]. This is then diluted with water to obtain a cuprous chloride precipitate. While this method, such as that employed in patent CN115367784A, can achieve a certain level of production, it consumes significant amounts of water resources. The resulting filtrate contains numerous impurity ions, a complex composition, and a relatively low concentration. Subsequent processing steps are complex and costly, and can easily lead to secondary pollution, posing a potential threat to the environment.

[0004] The scrap copper oxidation method uses scrap copper as raw material, directly oxidizing it with chlorine to produce copper ions. This reaction then causes the copper to react with the copper ions to form cuprous chloride. While suitable for large-scale production, the use of chlorine places extremely stringent demands on equipment materials, sealing, and safety features. The process is complex, and parameter control is challenging. This method faces numerous limitations in actual production, increasing equipment investment and operational risks for companies.

[0005] The solvothermal reduction method uses copper sulfate or copper chloride as the starting material, adding sodium chloride and a reducing agent to produce cuprous chloride. Taking patent CN109626411A as an example, although the process steps are relatively simple, impurities in the solution significantly affect the reaction, making it difficult to achieve a high purity level of the produced cuprous chloride product. This limits product quality, significantly reduces its economic value in the market, and fails to meet the strict purity requirements of cuprous chloride in high-end applications, resulting in a certain degree of resource waste and economic loss.

[0006] In summary, existing technologies for preparing cuprous chloride from copper-containing solid waste have significant shortcomings in terms of cost control, environmental performance, production efficiency, and product purity improvement, making it difficult to achieve an organic balance of economic, environmental, and resource recovery benefits. Therefore, developing an innovative, efficient, and environmentally friendly method for recovering copper from copper-containing solid waste and preparing high-purity cuprous chloride is of great practical significance and urgency, becoming a research hotspot and key breakthrough direction in the field of industrial solid waste resource utilization.

[0007] Therefore, the present application provides a method for recovering copper from copper-containing solid waste and preparing cuprous chloride. Summary of the Invention

[0008] In order to overcome the shortcomings of the existing technology, the present invention provides a method for recovering copper from copper-containing solid waste and preparing cuprous chloride. Through a multi-step impurity removal process, especially the extraction and stripping steps, a large amount of impurities are effectively removed, so that the purity of the prepared cuprous chloride can reach 99%. This overcomes the problems of high impurities and low purity of traditional process products and meets the strict requirements of high-end fields for the purity of cuprous chloride.

[0009] The technical solution adopted by the present invention to solve its technical problem is: A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: (1) Taking copper-containing solid waste residue, using acid solution to dissolve it, adding oxidant during the dissolution process, and performing solid-liquid separation after the dissolution is completed to obtain copper-containing solution and copper residue. The copper-containing solution enters the next process, and the copper residue is returned to continue dissolution; (2) using a regulator to adjust the pH of the copper-containing solution obtained in step (1) to 3-3.5, performing a regulation reaction, and after the reaction is completed, performing solid-liquid separation to obtain a regulated solution; (3) extracting the adjusted solution obtained in step (2) with an extractant, separating the extracted solution to obtain an organic phase; and stripping the organic phase with a stripping agent to obtain a stripping solution; (4) Adding an additive, a reducing agent, and a template to the stripping solution obtained in step (3) to obtain a mixture, and reacting the mixture at a pH of 2-2.5 for 5-8 hours. After the reaction is completed, solid-liquid separation is performed to obtain a white solid, which is rinsed and dried to obtain cuprous chloride.

[0010] In some specific embodiments, in step (1), the acid solution is a sulfuric acid solution, and the liquid-to-solid ratio of the acid solution to the copper-containing solid waste residue is controlled at 2-7:1 during the dissolution process, and the dissolution time is 1-3 hours.

[0011] In some specific embodiments, in step (1), the oxidant is any one of hydrogen peroxide, oxygen, chlorine, and sodium hypochlorite.

[0012] In some specific embodiments, in step (2), the regulator is any one of sodium hydroxide solution, calcium hydroxide solution, copper hydroxide, and copper oxide.

[0013] In some specific embodiments, in step (3), the extractant is formed by combining any one of a LIX extractant, a P507 extractant, and an N902 extractant with sulfonated kerosene.

[0014] In some specific embodiments, in step (4), the additive is any one of sodium chloride and potassium chloride.

[0015] In some specific embodiments, in step (4), the reducing agent is any one of sodium sulfite, sodium bisulfite, vitamin C, copper powder, and hydroxylamine hydrochloride.

[0016] In some specific embodiments, in step (4), the mixture is adjusted to pH=2-2.5 using sulfuric acid.

[0017] In some specific embodiments, in step (4), the template is polyvinyl pyrrolidone; the mixture is reacted at pH = 2-2.5 and 85-90°C for 5-8h.

[0018] In some specific embodiments, in step (3), the stripping agent is sulfuric acid.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The method described in the present application uses copper-containing solid waste as a copper source, uses an acid solution to dissolve soluble substances such as metallic copper and copper oxide therein, then uses an extractant to enrich the copper ions in the organic phase, and then strips the organic phase into a stripping solution. The stripping solution has a high copper ion concentration and very few impurity ions, and the purity of the prepared cuprous chloride can reach 99%.

[0020] The method described in the present application has a simple process, strong controllability, and a wide range of applications. It can be used to recover copper from various copper-containing solid wastes and prepare cuprous chloride with high economic value without generating secondary pollution, thereby realizing resource utilization of copper.

[0021] The method described in the present application can prepare micro-nano-level cuprous chloride, and the cuprous chloride has good stability, is not easily oxidized, and is very easy to store or transport. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings and examples.

[0023] Figure 1 This is a process flow chart of a method for recovering copper from copper-containing solid waste and preparing cuprous chloride as described in this application. DETAILED DESCRIPTION

[0024] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the embodiments. The contents mentioned in the embodiments are not intended to limit the present invention.

[0025] As used herein, the term "and / or" includes all combinations of any one or more of the associated listed items. The terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It is further understood that "including", when used in this specification, specifies the stated features, integers, steps, operations, elements and / or components, but does not preclude the existence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It is further understood that terms, such as those defined in commonly used dictionaries, are interpreted in accordance with their meanings in the context of the relevant art and are not idealized or overly formalized unless expressly defined otherwise herein.

[0027] The exemplary inventions described herein may suitably lack any one or more element limitations not specifically disclosed herein. Therefore, terms such as "comprises," "includes," "contains," and the like should be understood broadly and non-restrictively. In addition, the terminology used herein is used as a description, not a limitation, and it is unintentional to use these terminology expressions that do not include any equivalent characteristics, but only describe a portion of their characteristics, but various modifications are possible within the scope of the invention according to the rights. Therefore, although the present invention has been specifically disclosed through preferred embodiments and optional features, the modifications disclosed herein to embody the changes of the invention may be recorded by those skilled in the art, and such modifications and changes will be considered to be within the scope of the invention.

[0028] Explanation of terms: The LIX type extractant is mainly composed of ketoxime groups; the ketoxime groups in the LIX type extractant can form stable chelates with copper ions to generate extractants that are easily soluble in the organic phase, thereby achieving the extraction of copper ions.

[0029] P507 extractant, primarily composed of di(2-ethylhexyl)phosphoric acid, is an acidic phosphorus-based extractant. The phosphate groups in its molecules react with copper ions to form a stable copper phosphate extractant. Under acidic conditions, the copper ions' coordination capacity is enhanced, making them more likely to bind to the phosphate groups in P507, thereby transferring the copper ions from the aqueous phase to the organic phase.

[0030] N902 extractant, whose main component is 2-hydroxy-5-nonyl salicylaldoxime, belongs to the aldoxime family of extractants. The aldoxime group in N902 extractant can form a stable complex with copper ions. Under appropriate acidity conditions, the d-orbital electrons of the copper ions interact with the lone pair electrons of the aldoxime group to form a chelate that is easily soluble in the organic phase, achieving the extraction of copper ions.

[0031] The O / A ratio refers to the volume ratio of the organic phase to the aqueous phase.

[0032] like Figure 1 The method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: (1) Taking copper-containing solid waste residue, using acid solution to dissolve it, adding oxidant during the dissolution process, and performing solid-liquid separation after the dissolution is completed to obtain copper-containing solution and copper residue. The copper-containing solution enters the next process, and the copper residue is returned to continue dissolution; (2) using a regulator to adjust the pH of the copper-containing solution obtained in step (1) to 3-3.5, performing a regulation reaction, and after the reaction is completed, performing solid-liquid separation to obtain a regulated solution; (3) extracting the adjusted solution obtained in step (2) with an extractant, separating the extracted solution to obtain an organic phase; and stripping the organic phase with a stripping agent to obtain a stripping solution; (4) Adding an additive, a reducing agent, and a template to the stripping solution obtained in step (3) to obtain a mixture, and reacting the mixture at a pH of 2-2.5 for 5-8 hours. After the reaction is completed, solid-liquid separation is performed to obtain a white solid, which is rinsed and dried to obtain cuprous chloride.

[0033] Specifically, the copper-containing solid waste used in step (1) is one or more of dust from the steel industry, copper-containing slag produced by electroplating and chemical industries, and copper-containing tailings produced by hydrometallurgical processes; the acid solution used is a sulfuric acid solution, the concentration of the acid solution used is 1-4 mol / L, the liquid-solid ratio is maintained at 2-7:1 during the dissolution process, the dissolution temperature is room temperature, and the dissolution time is 1-3 h; the oxidant used is any one of oxygen, sodium hypochlorite, calcium hypochlorite, and hydrogen peroxide, and the molar amount of the oxidant added is 1%-10%.

[0034] In step (1), the acidity and oxidizing properties of the acid solution are used to dissolve metallic copper and copper oxide in the copper-containing solid waste. At the same time, the addition of an oxidant (such as oxygen, chlorine, sodium hypochlorite, etc.) can further promote the oxidation and dissolution of copper, so that more copper is converted into copper ions and enters the solution.

[0035] More specifically, in step (1), if the liquid-to-solid ratio is too large (exceeding 7:1), it will lead to excessive use of acid solution, increase costs, increase the volume of solution for subsequent treatment, and increase the burden of extraction and other processes, which may affect the overall production efficiency and economic benefits; at the same time, the copper ion concentration may be relatively reduced due to the dilution effect of the solution, which is not conducive to subsequent reactions.

[0036] If the liquid-solid ratio is too small (less than 2:1), the copper-containing solid waste cannot fully contact the acid solution and oxidant, resulting in incomplete dissolution of copper, reduced copper recovery rate, waste of raw materials, and reduced final cuprous chloride production.

[0037] If too much oxidant is added (more than 10%), it may trigger an over-oxidation reaction, producing excessive high-valent copper ions or other by-products, increasing the difficulty of subsequent impurity removal and affecting the purity of cuprous chloride; it may also cause waste of oxidant and increase costs.

[0038] If the amount of oxidant added is too small (less than 1%), the copper in the copper-containing solid waste cannot be fully oxidized, resulting in incomplete copper dissolution, reduced copper recovery rate, and affected the yield of cuprous chloride.

[0039] Specifically, in step (2), the regulator used is any one of sodium hydroxide solution, calcium hydroxide solution, copper hydroxide, and copper oxide, the concentration of the sodium hydroxide solution and calcium hydroxide solution used is 0.1-1 mol / L, and the stirring time is 0.5-1.5 h.

[0040] Specifically, in step (3), the extractant is formed by combining any one of LIX extractant, P507 extractant, and N902 extractant with sulfonated kerosene.

[0041] The O / A ratio used in the extraction is 2-7:1, the number of extraction stages is 3-6, the extraction method is cascade countercurrent extraction, the extraction temperature is 15-25°C, and the extraction time is 5-15 minutes; the stripping agent used in the back extraction is sulfuric acid, and the concentration of the stripping agent is 1-2 mol / L; the O / A ratio used in the back extraction is 2-8:1, the number of back extraction stages is 3-6, the back extraction temperature is 15-25°C, and the back extraction time is 5-15 minutes.

[0042] In this application, sulfuric acid is selected as the stripping agent. Sulfuric acid is a strong acid that can provide sufficient H + , these H + It can destroy the stability of the chelate, promote its dissociation, and transfer the copper ions from the organic phase back to the aqueous phase. In addition, sulfuric acid can effectively dissolve the copper ions and will not introduce other impurity ions during the stripping process, thus maintaining the purity of the solution. If hydrochloric acid is used as the stripping agent, hydrochloric acid will introduce a large amount of Cl -ions, which may form complex complexes with copper ions, affecting the effective separation and purification of copper. In addition, excessive Cl - Ions may cause side reactions and reduce the purity of the final product.

[0043] Specifically, in step (4), the additive is any one of sodium chloride and potassium chloride. The reducing agent is any one of sodium sulfite, sodium bisulfite, vitamin C, copper powder, and hydroxylamine hydrochloride. The pH of the mixture is adjusted to 2-2.5 using sulfuric acid. The template is polyvinyl pyrrolidone; and the mixture is reacted at a pH of 2-2.5 and a temperature of 85-90°C for 5-8 hours.

[0044] Solid-liquid separation is carried out by vacuum filtration or filtration under an inert atmosphere (nitrogen, argon, etc.). The rinsing liquid used is any one of water, methanol, ethanol, isopropanol, and acetone. The rinsing times are 1-2 times. The equipment used for drying is a vacuum drying oven, the drying temperature is 60-90°C, and the drying time is 3-5h.

[0045] In this application, sulfuric acid is used to adjust the pH to 2-2.5. Under acidic conditions, copper ions (Cu 2+ ) is more easily reduced to monovalent copper ions (Cu + ), which helps to form cuprous chloride (CuCl), and the acidic environment provided by sulfuric acid helps to maintain a suitable redox potential and promote the reaction.

[0046] In this application, an additive (such as sodium chloride, NaCl) is added. NaCl increases the ionic strength of the solution, helps inhibit nonspecific adsorption, and provides the chloride ions necessary for the formation of cuprous chloride without interfering with the formation of CuCl. The absence of NaCl may lead to nonspecific adsorption of certain impurity ions, affecting the purity of CuCl.

[0047] In this application, a reducing agent (such as sodium sulfite Na2SO3) is added to reduce part of the Cu 2+ Reduction to Cu + , and then form CuCl. The selection of a suitable reducing agent is crucial to maintain an appropriate redox potential, which directly affects the formation rate and quality of CuCl. Without sufficient reducing agent, Cu 2+ Cannot be completely converted into Cu + , resulting in a decrease in CuCl production and even the appearance of other forms of copper compounds.

[0048] In this application, the addition of a template (such as polyvinylpyrrolidone PVP) Reason: PVP, as a high-molecular compound, can adsorb onto the growing CuCl crystal surfaces in solution, preventing particle aggregation and maintaining a small particle size distribution in the final product. PVP also provides physical isolation, reducing oxygen contact with the CuCl surface and improving its antioxidant properties. Without the PVP template, the CuCl particles may become larger and more irregular, prone to agglomeration, and affect the micro- and nanostructure properties of the product.

[0049] In this application, the reaction temperature is set at 85-90°C. This temperature ensures sufficient thermal energy to promote the reaction rate, but is not too high to cause rapid particle growth or aggregation. This moderate temperature also helps maintain the stability and controllability of the reaction system. Too low a temperature will slow the reaction rate and prolong the reaction time; too high a temperature may lead to increased particle size or abnormal morphology.

[0050] The reaction time is set to 5-8 hours. This period is sufficient for the CuCl to fully precipitate without causing the particle size to increase or the morphology to change due to excessive reaction time. Insufficient reaction time will result in insufficient precipitation of the CuCl; excessive reaction time may lead to unnecessary side reactions, affecting product quality.

[0051] The following examples and comparative examples further illustrate the method for recovering copper from copper-containing solid waste and preparing cuprous chloride described in the present application. Example 1

[0052] A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: The composition of copper-containing solid waste from a steel plant is shown in Table 1.

[0053] Table 1 Composition of copper-containing solid waste from a steel plant

[0054] Step (1) The copper-containing solid waste shown in the table above was dissolved using a 2 mol / L sulfuric acid solution. The liquid-solid ratio was maintained at 4:1 during the dissolution process. The dissolution temperature was room temperature and the dissolution time was 2 h. Hydrogen peroxide was added as an oxidant during the dissolution process. The amount of hydrogen peroxide was 5%. After the reaction was completed, solid-liquid separation was performed to obtain a copper-containing solution and copper slag. The copper-containing solution entered the next step, and the copper slag was returned for further dissolution. The composition of the copper-containing solution is shown in Table 2 below.

[0055] Table 2 Composition of copper-containing solution

[0056] Step (2) Take the copper-containing solution shown in the above table, use copper oxide to adjust the pH of the system to 2, stir the reaction for 0.5h, and then perform solid-liquid separation to obtain a regulated solution.

[0057] Step (3) extracting the copper ions in the regulating solution using an extractant, wherein the extractant is composed of N902 and sulfonated kerosene, wherein the mass concentration of N902 is 30%, the extraction O / A ratio is 2:1, the number of extraction stages is 3, the extraction method is cascade countercurrent extraction, the extraction temperature is 15°C, and the extraction time is 5 minutes, to obtain an organic phase; The organic phase was stripped using sulfuric acid as the stripping agent at a concentration of 1 mol / L, an O / A ratio of 2:1, three stripping stages, a stripping temperature of 15°C, and a stripping time of 5 minutes. The composition of the resulting stripping solution is shown in Table 3 below.

[0058] Table 3 Composition of stripping solution

[0059] Step (4) Take the stripping solution shown in Table 3, adjust the pH to 2-2.5 with sulfuric acid, add sodium chloride as an additive, and stir evenly before adding reducing agents sodium sulfite and polyvinyl pyrrolidone, and stir until the molar ratio of sodium sulfite to the molar ratio of copper ions in the solution is 0.5:1. The amount of polyvinyl pyrrolidone added is 3% of the weight of sodium sulfite. After the addition is completed, react at 85°C for 8 hours. After the reaction was completed, a vacuum filter was used to perform solid-liquid separation to obtain cuprous chloride. After filtration, the composition of the filtrate was shown in Table 4 below. The obtained cuprous chloride was rinsed once with water and once with anhydrous ethanol. The rinsed solid was placed in a vacuum drying oven and dried at 60° C. for 3 h to obtain the cuprous chloride product.

[0060] Table 4 Composition of filtrate Example 2

[0061] A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: The composition of copper-containing solid waste from a steel plant is shown in Table 5 below.

[0062] Table 5 Composition of copper-containing solid waste from a steel plant

[0063] Step (1) The copper-containing solid waste shown in the table above was dissolved using a 1 mol / L sulfuric acid solution. The liquid-solid ratio was maintained at 2:1 during the dissolution process. The dissolution temperature was room temperature and the dissolution time was 1 hour. Hydrogen peroxide was added as an oxidant during the dissolution process. The amount of hydrogen peroxide was 1%. After the reaction was completed, solid-liquid separation was performed to obtain a copper-containing solution and copper slag. The copper-containing solution entered the next step, and the copper slag was returned for further dissolution. The composition of the copper-containing solution is shown in Table 6 below.

[0064] Table 6 Composition of copper-containing solution

[0065] Step (2) Take the copper-containing solution shown in the table above, use copper oxide to adjust the pH of the system to 3, stir the reaction for 1 hour, and then perform solid-liquid separation to obtain a regulated solution.

[0066] Step (3) extracting the copper ions in the conditioning solution using an extractant, wherein the extractant is composed of N902 and sulfonated kerosene, wherein the mass concentration of N902 is 40%, the extraction O / A ratio is 4:1, the number of extraction stages is 4, the extraction method is cascade countercurrent extraction, the extraction temperature is 20°C, and the extraction time is 10 min; The loaded organic phase was stripped using sulfuric acid solution as the stripping agent. The stripping agent concentration was 3 mol / L, the O / A ratio was 5:1, the number of stripping stages was four, the stripping temperature was 20°C, and the stripping time was 10 min. The composition of the resulting stripping solution is shown in Table 7 below.

[0067] Table 7 Composition of stripping solution

[0068] Step (4) Take the stripping solution shown in Table 7, adjust the pH to 2-2.5 with sulfuric acid, add sodium chloride as an additive, and stir evenly before adding reducing agents sodium sulfite and polyvinyl pyrrolidone, and stir until the molar ratio of sodium sulfite to the molar ratio of copper ions in the solution is 1.5:1. The amount of polyvinyl pyrrolidone added is 3% of the weight of sodium sulfite. After the addition is completed, react at 88°C for 6 hours. After the reaction is completed, a vacuum filter is used to separate the solid and liquid to obtain cuprous chloride. After filtration, the composition of the filtrate is shown in Table 8 below. The obtained cuprous chloride is rinsed twice with a 2 mol / L hydrochloric acid solution and twice with anhydrous ethanol. The rinsed solid is placed in a vacuum drying oven and dried at 70° C. for 4 h to obtain the cuprous chloride product.

[0069] Table 8 Composition of filtrate Example 3

[0070] A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: The composition of copper-containing solid waste from a steel plant is shown in Table 9 below.

[0071] Table 9 Composition of copper-containing solid waste from a steel plant

[0072] Step (1) The copper-containing solid waste shown in the table above was dissolved using a 4 mol / L sulfuric acid solution. The liquid-solid ratio was maintained at 7:1 during the dissolution process. The dissolution temperature was room temperature and the dissolution time was 3 h. Hydrogen peroxide was added as an oxidant during the dissolution process. The amount of hydrogen peroxide was 10%. After the reaction was completed, solid-liquid separation was performed to obtain a copper-containing solution and copper slag. The copper-containing solution entered the next step, and the copper slag was returned for further dissolution. The composition of the copper-containing solution is shown in Table 10 below.

[0073] Table 10 Composition of copper-containing solution

[0074] Step (2) Take the copper-containing solution shown in the above table, use copper oxide to adjust the pH of the system to 3.5, stir the reaction for 1.5 hours, and then perform solid-liquid separation to obtain a regulated solution.

[0075] Step (3) extracting the copper ions in the conditioning solution using an extractant, wherein the extractant is composed of N902 and sulfonated kerosene, wherein the mass concentration of N902 is 60%, the extraction O / A ratio is 7:1, the number of extraction stages is 6, the extraction method is cascade countercurrent extraction, the extraction temperature is 25°C, and the extraction time is 15 minutes; The loaded organic phase was stripped using sulfuric acid as the stripping agent at a concentration of 6 mol / L, an O / A ratio of 8:1, six stripping stages, a stripping temperature of 25°C, and a stripping time of 15 minutes. The composition of the resulting stripping solution is shown in Table 11.

[0076] Table 11 Composition of stripping solution

[0077] Step (4) Take the stripping solution shown in Table 7, adjust the pH to 2-2.5 with sulfuric acid, add sodium chloride as an additive, and stir evenly before adding reducing agents sodium sulfite and polyvinyl pyrrolidone, and stir until the molar ratio of sodium sulfite to the molar ratio of copper ions in the solution is 2:1. The amount of polyvinyl pyrrolidone added is 3% of the weight of sodium sulfite. After the addition is completed, react at 90°C for 5 hours. After the reaction is completed, a vacuum filter is used to separate the solid and liquid to obtain cuprous chloride. After filtration, the composition of the filtrate is shown in Table 12 below. The obtained cuprous chloride is rinsed twice with a 3 mol / L hydrochloric acid solution and twice with anhydrous ethanol. The rinsed solid is placed in a vacuum drying oven and dried at 90° C. for 5 h to obtain the cuprous chloride product.

[0078] Table 12 Composition of filtrate

[0079] Comparative Example 1 A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: In step (4), concentrated hydrochloric acid is used to adjust the pH of the stripping solution to 2-2.5; the other conditions are the same as those in Example 1.

[0080] Table 13 Components of the filtrate

[0081] Comparative Example 2 A method for recovering copper from copper-containing solid waste and preparing cuprous chloride comprises the following steps: In step (4), no template is added; the remaining conditions are the same as those in Example 1.

[0082] Table 14 Filtrate composition

[0083] The cuprous chloride prepared in Example 1-3 and Comparative Example 1-2 was analyzed by a laser particle size analyzer to determine the particle size, and the cuprous chloride content was determined by (HG / T2960-2000). The cuprous chloride sample was placed in an environment with a temperature of 45±5°C and a humidity of 75±5% for 15 minutes, and the color change of the cuprous chloride sample was observed; the copper ion resource utilization rate was calculated as follows: (1-initial concentration of copper ions in the stripping solution / concentration of copper ions in the filtrate) × 100%. The above results are summarized in Table 15 below.

[0084] Table 15 Test results

[0085] As can be seen from Table 15, the average particle sizes of Examples 1-3 are 15 μm, 18 μm, and 21 μm, respectively. These values indicate that the cuprous chloride prepared by this method has a particle size of micro-nano level.

[0086] The cuprous chloride contents of Examples 1-3 are 99.3%, 99.5% and 99.8%, respectively, indicating that the prepared cuprous chloride products are of very high purity and can meet the strict requirements of high-end fields for the purity of cuprous chloride.

[0087] Before and after the test, the color of cuprous chloride was white without significant change, which indicates that the prepared cuprous chloride has good antioxidant properties and is not easily oxidized and discolored.

[0088] The resource utilization rates of copper ions in Examples 1-3 reached 96.07%, 96.25% and 96.91%, respectively, indicating that most of the copper ions were effectively converted into cuprous chloride, and the resource recovery efficiency was high.

[0089] Comparative Example 1, average particle size: 56 microns, cuprous chloride content: 78.6%, color change: white before the test, turned light green after the test; copper ion resource utilization rate: 76.06%. It can be seen that the cuprous chloride product in Comparative Example 1 is significantly lower in purity and antioxidant performance than Example 1. Its average particle size is larger and it is prone to oxidation discoloration under high temperature and high humidity environments. Therefore, the main difference between Comparative Example 1 and Example 1 is that concentrated hydrochloric acid is used instead of sulfuric acid when adjusting the pH. Concentrated hydrochloric acid may introduce more impurities or cause the reaction conditions to be less stable than sulfuric acid, thereby affecting the purity and particle size of the final product; in addition, concentrated hydrochloric acid may cause excessive Cl in the solution. - ions, which may promote the occurrence of side reactions and reduce the production efficiency and purity of cuprous chloride.

[0090] Comparative Example 1: Average particle size: 89 microns, cuprous chloride content: 97.5%, color change: light green before testing, yellow-green after testing; copper ion resource utilization rate: 92.82%. It can be seen that although the cuprous chloride product in Comparative Example 2 has a higher purity, it is still lower than that of Example 1, and its antioxidant properties are poor, with a significant color change under high temperature and high humidity conditions. Furthermore, the product's particle size is much larger than that of Example 1.

[0091] Therefore, the main difference between Comparative Example 2 and Example 1 is that no template agent (such as polyvinyl pyrrolidone) is added. The function of the template agent is to control crystal growth and prevent particle aggregation, thereby obtaining smaller and evenly distributed particles. The lack of a template agent will lead to uncontrolled crystal growth and the formation of larger particles. It will also increase the tendency of agglomeration between particles and reduce the antioxidant properties of the product. The absence of a template agent not only affects the particle size of cuprous chloride, but also has a negative impact on its antioxidant properties and purity.

[0092] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the scope of protection of the present invention.

Claims

1. A method for recovering copper from copper-containing solid waste and preparing cuprous chloride, characterized in that: The following steps are involved: (1) Taking copper-containing solid waste residue, using acid solution to dissolve it, adding oxidant during the dissolution process, and performing solid-liquid separation after the dissolution is completed to obtain copper-containing solution and copper residue. The copper-containing solution enters the next process, and the copper residue is returned to continue dissolution; (2) using a regulator to adjust the pH of the copper-containing solution obtained in step (1) to 3-3.5, performing a regulation reaction, and after the reaction is completed, performing solid-liquid separation to obtain a regulated solution; (3) extracting the adjusted solution obtained in step (2) with an extractant, separating the extracted solution to obtain an organic phase; and stripping the organic phase with a stripping agent to obtain a stripping solution; (4) Adding an additive, a reducing agent, and a template to the stripping solution obtained in step (3) to obtain a mixture, and reacting the mixture at a pH of 2-2.5 for 5-8 hours. After the reaction is completed, solid-liquid separation is performed to obtain a white solid, which is rinsed and dried to obtain cuprous chloride.

2. The method according to claim 1, characterized in that In step (1), the acid solution is a sulfuric acid solution, and the liquid-solid ratio of the acid solution to the copper-containing solid waste is controlled at 2-7:1 during the dissolution process, and the dissolution time is 1-3 hours.

3. The method according to claim 1, characterized in that In step (1), the oxidant is any one of oxygen, chlorine, and sodium hypochlorite.

4. The method according to claim 1, wherein In step (2), the regulator is any one of sodium hydroxide solution, calcium hydroxide solution, copper hydroxide, and copper oxide.

5. The method according to claim 1, wherein In step (3), the extractant is formed by combining any one of LIX extractant, P507 extractant, and N902 extractant with sulfonated kerosene.

6. The method according to claim 1, characterized in that In step (4), the additive is any one of sodium chloride and potassium chloride.

7. The method according to claim 1, characterized in that In step (4), the reducing agent is any one of sodium sulfite, sodium bisulfite, vitamin C, copper powder, and hydroxylamine hydrochloride.

8. The method according to claim 1, characterized in that In step (4), the mixture is adjusted to pH=2-2.5 using sulfuric acid.

9. The method according to claim 1, characterized in that In step (4), the template agent is polyvinyl pyrrolidone; the mixture is reacted at pH = 2-2.5 and 85-90°C for 5-8h.

10. The method according to claim 1, characterized in that In step (3), the stripping agent is sulfuric acid.

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