A preparation process for recovering cuprous chloride from copper-containing etching solution

Abstract

The application relates to a preparation process for recovering cuprous chloride from copper-containing etching solution, which comprises the following steps: S1, mixing the copper-containing etching solution with an extractant to perform extraction, and collecting a copper-containing organic phase through liquid separation; S2, back-extracting the copper-containing organic phase collected in the step S1 with hydrochloric acid, collecting a back-extraction liquid and a raffinate through liquid separation; S3, adding sodium sulfite into the back-extraction liquid collected in the step S2 to generate a cuprous chloride precipitate through reaction, collecting a cuprous chloride crude product and a filtrate through solid-liquid separation; S4, washing the cuprous chloride crude product collected in the step S3 with ethanol, and obtaining a cuprous chloride product after washing; and S5, adding liquid alkali into the filtrate collected in the step S3 to make residual copper ions precipitate, filtering and collecting the solid, dissolving the solid with copper-containing etching solution, and then entering the step S1 for reaction and utilization. Through the whole-process system of "extraction-back extraction-reduction-purification-residual liquid closed loop recycling", the application realizes efficient enrichment and extreme recovery of copper resources.

Description

Technical Field

[0001] This application relates to the field of waste liquid treatment technology, and in particular to a preparation process for recovering cuprous chloride from copper-containing etching solutions. Background Technology

[0002] Copper-containing etching solutions are one of the main waste liquids generated during the manufacturing of printed circuit boards. They have high copper ion concentrations and their annual production continues to increase. Direct discharge of these solutions causes both heavy metal pollution and wastes copper resources. Cuprous chloride, as an important chemical raw material, is widely used in organic synthesis catalysts, dye industries, and other fields. Using copper-containing etching solutions as raw materials to prepare cuprous chloride can achieve the dual goals of waste liquid resource utilization and the production of high-value-added products.

[0003] Currently, methods for recovering copper from copper-containing waste liquid mainly include chemical precipitation, displacement, electrolysis, and solvent extraction. Chemical precipitation is simple but produces low-purity products; displacement is easy to operate but produces poor-purity products and generates secondary waste liquid; electrolysis produces high-purity products but consumes a lot of energy and requires high investment; solvent extraction has good selectivity but the extractant is expensive, easily lost, and requires further treatment of organic matter in the raffinate, resulting in a long overall process chain. In the preparation of cuprous chloride, existing technologies mostly employ direct reduction precipitation, which requires high purity of the raw material solution. Impurities in the etching solution easily co-precipitate with the product, affecting quality. Furthermore, residual copper ions in the filtrate after reduction are often directly discharged or simply treated, resulting in resource loss. Existing technology CN115928078B discloses a system for neutralizing and precipitating cuprous chloride through acid-base etching waste liquid and achieving waste liquid recycling. However, this scheme relies on production scenarios with both acidic and alkaline etching waste liquids, limiting its applicability, and it does not further recover residual copper ions from the filtrate.

[0004] Therefore, how to improve the applicability of raw materials, reduce impurity interference, and optimize the comprehensive recovery rate of copper resources while ensuring the quality of cuprous chloride products remains a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] To optimize the overall recovery rate of copper resources, this application provides a preparation process for recovering cuprous chloride from copper-containing etching solutions.

[0006] A preparation process for recovering cuprous chloride from copper-containing etching solution includes the following steps: S1. Mix the copper-containing etching solution with the extractant and extract, then separate and collect the copper-containing organic phase. S2. The copper-containing organic phase collected in step S1 is back-extracted with hydrochloric acid, and the back-extracted liquid and raffinate are collected by separation. S3. Add sodium sulfite to the back-extraction solution collected in step S2. The reaction produces cuprous chloride precipitate. After solid-liquid separation, collect crude cuprous chloride and filtrate. S4. Wash the crude cuprous chloride collected in step S3 with ethanol to obtain the cuprous chloride product. S5. Add liquid alkali to the filtrate collected in step S3 to precipitate the residual copper ions, filter and collect the solid, dissolve the solid with copper-containing etching solution, and then proceed to step S1 for reaction and utilization.

[0007] This application first utilizes an extractant to efficiently enrich copper into the organic phase from a copper-containing etching solution, followed by deep back-extraction with hydrochloric acid to obtain a high-purity copper-rich solution. Then, sodium sulfite is added to the solution to precisely reduce divalent copper to cuprous chloride precipitate. After solid-liquid separation, the crude product is washed with ethanol to remove impurities and prevent oxidation, ultimately yielding a high-purity cuprous chloride product. Simultaneously, the process involves adding alkali to the filtrate after precipitation to recover residual copper, which is then dissolved and reused in the initial etching solution. Combined with the recycling of the raffinate, a complete green zero-emission system of "extraction-back-extraction-reduction-purification-residual liquid closed-loop recycling" is constructed, achieving the ultimate high-value recovery of copper resources.

[0008] In one specific implementation, the extractant in step S1 includes a copper extractant and kerosene; more preferably, the copper extractant is selected from one or both of N902 and LIX84I; more preferably, the copper extractant includes N902 and LIX84I, and the mass ratio of N902 to LIX84I is 1:(1-3).

[0009] The inventors discovered that in traditional acidic copper chloride etching solutions, copper is mainly present as [CuCl4]. 2- Copper oxime exists in isochloride complex form and is chemically stable. While conventional single aldoxime extractants (such as N902) offer high extraction capacity, subsequent hydrochloric acid back-extraction is extremely difficult due to the strong complexing competition of chloride ions and the high stability of the copper aldoxime complex. This often requires extremely high acid concentrations and results in incomplete back-extraction, leading to copper accumulation in the organic phase and decreased circulation efficiency. On the other hand, while ketoxime extractants (such as LIX84I) offer excellent back-extraction performance and fast kinetics, they suffer from lower extraction capacity, relatively weaker selectivity for copper, and a low extraction equilibrium constant at low acidity, resulting in low extraction rates. This makes them unsuitable for handling large volumes of high-concentration etching solutions, and their use alone is costly.

[0010] Experiments have verified that when N902 (an aldoxime-based copper extractant) and LIX84I (a ketoxime-based copper extractant) are compounded in the aforementioned mass ratio and dissolved in kerosene, a significant kinetic synergistic extraction effect is observed. N902, containing hydroxyl and oxime groups, forms a stable five-membered ring chelate structure with copper ions, providing high extraction capacity and selectivity. LIX84I, a ketoxime, has a short alkyl chain and low steric hindrance, facilitating rapid coordination and dissociation with copper ions. In the compounding process, the rigid chelate structure of N902 ensures selective extraction, while the flexible structure of LIX84I provides a channel for rapid mass transfer. Furthermore, during the hydrochloric acid back-extraction stage, high concentrations of LIX84I, with its large back-extraction equilibrium constant, effectively break the stable "chlorine-copper-aldexime" complex structure in the copper chloride system. Specifically, the complex formed by LIX84I and copper exhibits lower stability, significantly lower than the formation constant of N902. When both extractants coexist, copper ions rapidly exchange between them, significantly reducing the total activation energy of the back-extraction reaction and substantially improving the back-extraction efficiency. Kerosene, as an inert diluent, not only adjusts the viscosity of the extractant to improve two-phase flowability and prevent emulsification, but also further optimizes the spatial configuration of the extractant through solvation, allowing N902 and LIX84I to be uniformly dispersed in the organic phase, forming a dynamically balanced mixed micelle structure. This effectively increases the contact area between the two phases and improves mass transfer efficiency.

[0011] When the proportion of N902 is too high, the proportion of ketoxime extractants is too low, which cannot effectively reduce the back-extraction barrier, resulting in a significant decrease in the back-extraction rate and the problem of copper accumulation in the organic phase is not fundamentally solved. When the proportion of LIX84I is too high, the proportion of ketoxime extractants is too high. Although the back-extraction performance is good, the overall extraction capacity decreases significantly. Moreover, due to the poor selectivity of LIX84I for iron, the iron ion content in the product increases, affecting product quality. At the same time, the cost of extractants increases significantly, and the economic efficiency decreases.

[0012] In one specific implementation, the raffinate collected in step S2 is used as an extractant and recycled in step S1.

[0013] In traditional extraction-back-extraction processes, the organic phase after back-extraction is typically treated as waste liquid or requires complex regeneration processes, resulting in high extractant consumption and operating costs. This application discovers that the extractant in the raffinate obtained after hydrochloric acid back-extraction retains its complete chelating activity, and its chemical structure has not undergone irreversible changes, allowing it to be directly reused in the extraction process. By constructing a closed loop of "extraction-back-extraction-organic phase reuse," the recycling of the extractant is achieved, significantly reducing extractant consumption and the generation of waste organic phase.

[0014] In one specific implementation scheme, the concentration of hydrochloric acid used in the back-extraction process in step S2 is controlled at 120-180 g / L, and the pH value of the back-extraction solution after back-extraction is less than 1.0.

[0015] The essence of the back-extraction process is to disrupt the chelate structure formed between the extractant and copper ions, thereby competitively displacing Cu²⁺ through a high concentration of H⁺. When the hydrochloric acid concentration is controlled at 120-180 g / L, the pH value of the back-extraction solution can drop below 1.0. At this point, the H⁺ activity in the system is extremely high, which can effectively break the stable "chlorine-copper-extractant" complex structure in the copper chloride system, allowing the back-extraction reaction (CuR₂ + 2H⁺ ⇌ 2RH + Cu²⁺) to proceed smoothly. 2+ Proceed entirely to the right.

[0016] In one specific implementation, the amount of sodium sulfite added in step S3 is 10-30 wt% of the total amount of the back-extraction solution.

[0017] The reaction equation for the reduction of Cu²⁺ to CuCl by sodium sulfite is: 2Cu²⁺ + SO₃²⁻ + 2Cl⁻ + H₂O → 2CuCl↓ + SO₄²⁻ + 2H⁺. Theoretical calculations show that 0.5 moles of sodium sulfite are required to reduce 1 mole of copper ions (i.e., the molar ratio of sodium sulfite to copper ions is 0.5:1). However, in the actual reaction process, due to the potential oxidation of sodium sulfite by oxygen in the air and the presence of other oxidizing substances in the system, an appropriate excess is needed to ensure complete reduction of copper ions. When the amount of sodium sulfite added is 10-30 wt% of the total amount of the back-extraction solution, its molar amount is approximately 1.0-2.0 times the molar amount of copper ions in the back-extraction solution, which is precisely the optimal balance point between the theoretical requirement and the safety margin. On the one hand, this ensures that the copper ions in the back-extraction solution are fully reduced to cuprous chloride precipitate; on the other hand, it avoids reagent waste and side reactions caused by excessive sodium sulfite.

[0018] In one specific implementation scheme, the sodium sulfite described in step S3 is added to the back-extraction solution in equal amounts in 2-4 batches, with an interval of 5-15 minutes between each batch.

[0019] The crystal growth process of cuprous chloride precipitate is significantly affected by the reduction reaction rate. If all sodium sulfite is added at once, the reaction proceeds rapidly, resulting in an excessively fast crystal nucleation rate. This leads to small, unevenly distributed cuprous chloride crystals, making filtration and washing difficult, and the fine crystals easily penetrate the filter cloth, causing product loss. By adding equal amounts of sodium sulfite in 2-4 batches, with each batch spaced 5-15 minutes apart, the reduction reaction proceeds gradually, allowing the crystals to grow uniformly over a longer period, forming larger, denser cuprous chloride crystals. This significantly improves the product's filtration performance and final purity.

[0020] In one specific feasible implementation, the reaction temperature of step S3 is 20-80°C.

[0021] While ensuring the reaction rate, the risk of high-temperature oxidation is avoided. Too low a temperature (<20°C) results in slow reaction kinetics and incomplete crystal growth; too high a temperature (>80°C) accelerates the disproportionation reaction of monovalent copper ions in acidic solutions and their oxidation by air, leading to black copper oxide impurities in the product and reducing whiteness and purity. The wide temperature range of 20-80°C balances production efficiency and product quality.

[0022] In one specific implementation, the washing liquid generated from washing the crude cuprous chloride product with ethanol in step S4 is then recovered by distillation, and the recovered ethanol is reused in step S4.

[0023] When crude cuprous chloride is washed with ethanol, the main components of the washing solution are more than 90% ethanol, 5-10% water, and trace amounts of impurities such as cuprous chloride and cuprous chloride. Since ethanol and water form an azeotrope, ethanol and water can be effectively separated through distillation. The ethanol recovered by distillation has a stable concentration and can be reused in the washing step, which can effectively reduce ethanol consumption, lower costs, realize resource recycling, and help optimize the comprehensive recovery rate of copper resources.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. This application achieves efficient enrichment and ultimate recovery of copper resources by adopting a complete process system of "extraction-back-extraction-reduction-purification-closed-loop reuse of residual liquid".

[0025] 2. This application, by adopting a combined extractant system of N902 and LIX84I, produced a significant synergistic effect, taking into account high extraction capacity, high selectivity and easy back-extraction characteristics, effectively improving the purity and recovery rate of nitrite products.

[0026] 3. This application achieves multiple benefits of energy reduction and environmental protection by optimizing processes such as low-temperature reduction, stepwise addition of sodium sulfite, and distillation and reuse of ethanol washing liquid. Attached Figure Description

[0027] Figure 1 This is a flowchart of the preparation process for recovering cuprous chloride from copper-containing etching solution according to this application. Detailed Implementation

[0028] The present application will be further described in detail below with reference to embodiments and comparative examples: Some of the raw materials used in the examples and comparative examples: N902 (Product name: Copper extractant N902, item number: lbw8566, purchased from Hubei Langbowan Biomedical Co., Ltd.); LIX84I (Product name: Copper extractant LIX84I, model: 5541471, purchased from Hubei Maidehao Biotechnology Co., Ltd.).

[0029] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available products.

[0030] The copper-containing etching solution in this application has the following composition: CuCl2 is 1.790 mol / L and HCl is 3.114 mol / L. Example

[0031] Example 1 A preparation process for recovering cuprous chloride from copper-containing etching solution includes the following steps: S1. 80L of copper-containing etching solution (containing 1.790mol / L CuCl2, 143.2mol of Cu²⁺ (equivalent to 9.10kg of copper), and 3.114mol / L HCl) was mixed with 400L of extraction solvent (a mixture of N902, LIX84I, and kerosene in a mass ratio of 1:2:12) for extraction. The mixture was stirred and extracted for 10 minutes, allowed to stand for phase separation, and the copper-containing organic phase was collected by separation. S2. The copper-containing organic phase collected in step S1 is back-extracted with 150 g / L hydrochloric acid for 10 minutes. After standing and phase separation, the back-extract and raffinate are collected separately. The raffinate is used as an extractant in step S1 for recycling. The pH of the back-extract after back-extraction is <1.0.

[0032] S3. Add sodium sulfite to the back-extraction solution collected in step S2, with the amount of sodium sulfite being 20 wt% of the total back-extraction solution. Add the sodium sulfite in three equal batches, with an interval of 10 minutes between each batch. Control the reaction temperature at 45°C. During the reaction, a white cuprous chloride precipitate will form. After the reaction is complete, separate the solid and liquid phases, and collect the crude cuprous chloride product and the filtrate. S4. Wash the crude cuprous chloride collected in step S3 with ethanol three times, each time using twice the amount of ethanol as the crude product. After washing, the cuprous chloride product is obtained. The washing liquid generated during washing is distilled to recover ethanol. The temperature at the top of the distillation column is controlled at 80°C and the temperature at the bottom of the column is controlled at 105°C. The concentration of the recovered ethanol is ≥95%. The recovered ethanol is reused in step S4.

[0033] S5. Add 30% liquid alkali to the filtrate collected in step S3, adjust the pH to 8, so that the residual copper ions precipitate, filter and collect the solid, dissolve the solid in 16L of copper-containing etching solution, and then proceed to step S1 for reaction and utilization.

[0034] In this embodiment, a total of 96L of copper-containing etching solution was used, and 16.96kg of cuprous chloride product was obtained. The purity of the product was determined to be 99.92% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 99.71%.

[0035] Example 2 The only difference between Example 2 and Example 1 is that in step S1 of Example 2, the 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:2:12) is replaced with 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 2:1:12).

[0036] In this embodiment, a total of 96L of copper-containing etching solution was used, and 16.72kg of cuprous chloride product was obtained. The purity of the product was determined to be 99.45% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 98.29%.

[0037] Example 3 The only difference between Example 3 and Example 1 is that in step S1 of Example 3, the 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:2:12) is replaced with 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:4:20).

[0038] In this embodiment, a total of 96L of copper-containing etching solution was used, and 16.85kg of cuprous chloride product was obtained. The purity of the product was determined to be 99.85% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 99.06%.

[0039] Example 4 The only difference between Example 4 and Example 1 is that in step S1 of Example 4, the 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:2:12) is replaced with 400L extractant (a mixture of N902 and kerosene in a mass ratio of 1:4).

[0040] In this embodiment, a total of 96L of copper-containing etching solution was used, and 16.25kg of cuprous chloride product was obtained. The purity of the product was determined to be 99.15% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 95.52%.

[0041] Example 5 The only difference between Example 5 and Example 1 is that in step S1 of Example 5, the 400L extractant (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:2:12) is replaced with 400L extractant (a mixture of LIX84I and kerosene in a mass ratio of 1:4).

[0042] In this embodiment, a total of 96L of copper-containing etching solution was used, and 16.05kg of cuprous chloride product was obtained. The purity of the product was determined to be 99.05% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 94.36%.

[0043] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not recycle the filtrate collected in step S3, and the 80L copper-containing etching solution in step S1 was replaced with 96L copper-containing etching solution. The preparation process is as follows: S1. 96L of copper-containing etching solution (containing CuCl2 concentration of 1.790mol / L, total Cu²⁺ content of 143.2mol, equivalent to copper mass of 9.10kg, and HCl concentration of 3.114mol / L) was mixed with 400L of extraction solvent (a mixture of N902, LIX84I and kerosene in a mass ratio of 1:2:12) for extraction. The mixture was stirred and extracted for 10 minutes, allowed to stand for phase separation, and the copper-containing organic phase was collected by separation. S2. The copper-containing organic phase collected in step S1 is back-extracted with 150 g / L hydrochloric acid for 10 minutes. After standing and phase separation, the back-extract and raffinate are collected separately. The raffinate is used as an extractant in step S1 for recycling. The pH of the back-extract after back-extraction is <1.0.

[0044] S3. Add sodium sulfite to the back-extraction solution collected in step S2, with the amount of sodium sulfite being 20 wt% of the total back-extraction solution. Add the sodium sulfite in three equal batches, with an interval of 10 minutes between each batch. Control the reaction temperature at 45℃. During the reaction, a white cuprous chloride precipitate will form. After the reaction is complete, separate the solid and liquid phases, and collect the crude cuprous chloride product and the filtrate. S4. Wash the crude cuprous chloride collected in step S3 with ethanol three times, each time using twice the amount of ethanol as the crude product. After washing, the cuprous chloride product is obtained. The washing liquid generated during washing is distilled to recover ethanol. The temperature at the top of the distillation column is controlled at 80°C and the temperature at the bottom of the column is controlled at 105°C. The concentration of the recovered ethanol is ≥95%. The recovered ethanol is reused in step S4.

[0045] In this embodiment, a total of 96L of copper-containing etching solution was used, and 15.88kg of cuprous chloride product was obtained. The purity of the product was determined to be 98.20% by high performance liquid chromatography and chemical analysis, and the total yield based on copper was 93.36%.

[0046] The purity and yield of cuprous chloride products measured under the preparation processes of each embodiment and comparative example are summarized in the table below: Table 1. Record of purity and yield data for cuprous chloride products. Group Cuprous chloride - purity % Cuprous chloride - Yield % Example 1 99.92 99.71 Example 2 99.45 98.29 Example 3 99.85 99.06 Example 4 99.15 95.53 Example 5 99.05 94.36 Comparative Example 1 98.20 93.36 As can be seen from Examples 1-5 and Table 1, the composition and compounding ratio of the extractant have a decisive influence on the purity and yield of the cuprous chloride product. In Example 1, the extractant used was a compound of N902 and LIX84I in a preferred mass ratio, which produced a significant synergistic effect: N902 provided high extraction capacity and high selectivity, ensuring efficient and high-purity extraction of copper from the etching solution; LIX84I, with its characteristics of low steric hindrance, fast reaction kinetics, and large back-extraction equilibrium constant, effectively broke the stable "chlorine-copper-aldehyde oxime" complex structure in the copper chloride system, significantly reducing the back-extraction energy barrier. When the compounding ratio deviated from the preferred range, if the proportion of LIX84I was too low, back-extraction became difficult, leading to copper accumulation in the organic phase; the total concentration of the extractant decreased, resulting in a decrease in extraction capacity; single aldehyde oxime extractants were difficult to back-extract; and single ketone oxime extractants had low extraction capacity and poor selectivity. This indicates that the extractant must simultaneously satisfy the requirements of "aldexamethasone and ketoxime combination" and have its mass ratio controlled within an optimal range in order to achieve a synergistic balance between high extraction capacity and easy back-extraction characteristics.

[0047] Combining Example 1 and Comparative Example 1, and referring to Table 1, it can be seen that the filtrate reuse step plays a crucial role in improving the overall recovery rate of copper resources. In Example 1, residual copper ions were precipitated by adding liquid alkali to the filtrate after reduction precipitation, and then dissolved in copper-containing etching solution before being reused in the extraction process, thus constructing a "closed-loop recovery system for residual copper ions." In contrast, Comparative Example 1 did not perform filtrate reuse treatment, and the residual copper ions in the filtrate were directly discharged, resulting in copper resource loss. This indicates that by reusing the filtrate through sedimentation, trace amounts of copper ions in the filtrate after reduction precipitation can be completely recovered, which is a key guarantee for achieving ultimate copper resource recovery.

[0048] This application constructs a synergistic system of "high extraction capacity and easy back-extraction" by combining N902 and LIX84I as extractants. The synergistic system constructs a closed-loop recovery path for residual copper ions by adding alkali to the filtrate for sedimentation and dissolving and reusing copper-containing etching solution. This effectively improves the high-value recovery level of copper resources in copper-containing etching solution. While ensuring the high purity of the product, it achieves the ultimate recovery of copper resources and achieves a balance between economic and environmental benefits.

[0049] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A preparation process for recovering cuprous chloride from copper-containing etching solution, characterized in that, Includes the following steps: S1. Mix the copper-containing etching solution with the extractant and extract, then separate and collect the copper-containing organic phase. S2. The copper-containing organic phase collected in step S1 is back-extracted with hydrochloric acid, and the back-extracted liquid and raffinate are collected by separation. S3. Add sodium sulfite to the back-extraction solution collected in step S2. The reaction produces cuprous chloride precipitate. After solid-liquid separation, collect crude cuprous chloride and filtrate. S4. Wash the crude cuprous chloride collected in step S3 with ethanol to obtain the cuprous chloride product. S5. Add liquid alkali to the filtrate collected in step S3 to precipitate the residual copper ions, filter and collect the solid, dissolve the solid with copper-containing etching solution, and then proceed to step S1 for reaction and utilization.

2. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, The extractant mentioned in step S1 includes copper extractant and kerosene.

3. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 2, characterized in that, The copper extractant is selected from one or both of N902 and LIX84I.

4. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 3, characterized in that, The copper extractant comprises N902 and LIX84I, wherein the mass ratio of N902 to LIX84I is 1:(1-3).

5. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, The raffinate collected in step S2 is used as an extractant and then recycled in step S1.

6. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, In step S2, the concentration of hydrochloric acid used in the back-extraction process is controlled at 120-180 g / L, and the pH value of the back-extraction solution after back-extraction is less than 1.

0.

7. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, The amount of sodium sulfite added in step S3 is 10-30 wt% of the total amount of the back-extraction solution.

8. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, In step S3, sodium sulfite is added to the back-extraction solution in equal amounts in 2-4 batches, with an interval of 5-15 minutes between each batch.

9. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, The reaction temperature in step S3 is 20-80°C.

10. The preparation process for recovering cuprous chloride from copper-containing etching solution according to claim 1, characterized in that, In step S4, the washing liquid generated by washing the crude cuprous chloride product with ethanol is then recovered by distillation, and the recovered ethanol is reused in step S4.

Images