Method for preparing cupric sulfate pentahydrate by using a two-liquid type acidic etching solution

Abstract

The present application relates to the technical field of recovery of double-liquid type acidic etching solution in PCB industry, and specifically discloses a method for preparing copper sulfate pentahydrate from double-liquid type acidic etching solution. The method for preparing copper sulfate pentahydrate from double-liquid type acidic etching solution comprises the following steps: 1) adding double-liquid type acidic etching solution into sodium hydroxide solution with a temperature of 75-85 DEG C, and after 2-3 hours of reaction, performing primary filtration to obtain crude copper oxide, and then washing the crude copper oxide to obtain pure copper oxide; 2) after the pure copper oxide is reacted with sulfuric acid solution, electroplating grade copper sulfate pentahydrate is prepared through cold crystallization; wherein, the sodium hydroxide solution in step 1-1 is a 10wt%-12wt% sodium hydroxide solution; the volume ratio of the sodium hydroxide solution to the double-liquid type acidic etching solution is (2-2.5):1. The present application has the characteristics of simple process, low cost, green environmental protection, and high purity of copper sulfate pentahydrate.

Description

TECHNICAL FIELD

[0001] The application relates to a recovery technology of a double-liquid type acidic etching liquid in the PCB industry, in particular to a method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid. BACKGROUND

[0002] Copper sulfate pentahydrate (CuSO4.5H2O) is also called blue vitriol and vitriol of Glauber, which is widely used in the fields of pesticides, medicines and electronics, and is a very important inorganic compound.

[0003] At present, with the rapid development of the PCB industry, the amount of the double-liquid type acidic etching liquid generated also increases year by year. In the prior art, the method for preparing copper sulfate pentahydrate from the double-liquid type acidic etching liquid mainly includes the following steps: a neutralization and precipitation reaction is generated between the double-liquid type acidic etching liquid and alkali to generate basic copper chloride, or the double-liquid type acidic etching liquid is subjected to multi-effect evaporation and crystallization separation into dilute hydrochloric acid and copper chloride crystals, and then the copper chloride is used as an intermediate to generate copper sulfate. Such a method will cause a certain amount of chloride ions to remain in the copper sulfate solution, so that the quality of the copper sulfate pentahydrate crystals produced is not high, and it is difficult to reach the electroplating grade.

[0004] In view of the above related technologies, it is necessary to further improve the process for producing copper sulfate pentahydrate from the double-liquid type acidic etching liquid, so as to improve the purity of the copper sulfate pentahydrate. SUMMARY

[0005] In order to improve the purity of the copper sulfate pentahydrate, the electroplating grade copper sulfate pentahydrate can be obtained through one-time crystallization. The application provides a method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid. The application first prepares pure copper oxide solid, and then reacts the pure copper oxide with a sulfuric acid solution to obtain a copper sulfate solution. The amount of other impurity ions, especially chloride ions, remaining in the copper sulfate solution prepared by such a method is significantly reduced. The copper sulfate solution is used to obtain the electroplating grade copper sulfate pentahydrate through one-time freezing crystallization. Such a preparation method will not further produce harmful substances such as acid gas, and will not further cause environmental pollution. The method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid provided by the application has the characteristics of simple process, low cost, green environmental protection and high purity of the copper sulfate pentahydrate.

[0006] The method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid provided by the application adopts the following technical scheme: a method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid, the method for preparing copper sulfate pentahydrate from a double-liquid type acidic etching liquid comprises the following steps:

[0007] Step 1: preparing pure copper oxide solid;

[0008] Step 1-1: Add the dual-liquid acidic etching liquid to the sodium hydroxide solution at a temperature of 75-85℃, and after 2-3h of reaction, obtain a primary filtrate and crude copper oxide solid through primary filtration;

[0009] Step 1-2: Wash and centrifuge the crude copper oxide solid to obtain pure copper oxide solid;

[0010] Step 2: Prepare electroplating-grade copper sulfate pentahydrate;

[0011] Step 2-1: Take an appropriate amount of sulfuric acid and pure water and add them to the pure copper oxide solid obtained in Step 1 to obtain a copper sulfate solution;

[0012] Step 2-2: Perform primary freeze crystallization on the copper sulfate solution obtained in Step 2-1 to obtain a primary cooled copper sulfate solution and copper sulfate pentahydrate crystals, which are electroplating-grade copper sulfate pentahydrate;

[0013] In the method for preparing copper sulfate pentahydrate using the dual-liquid acidic etching liquid, the sodium hydroxide solution in Step 1-1 is a 10-12wt% sodium hydroxide solution;

[0014] The volume ratio of the sodium hydroxide solution to the dual-liquid acidic etching liquid is (2-2.5):1;

[0015] The primary filtration refers to high-speed centrifugation at a separation factor of 1000-1200;

[0016] The washing refers to washing with pure water having a tds of <5mg / L until the tds of the washing filtrate is <50mg / L.

[0017] In the above technical method, the sodium hydroxide solution is heated to 75-85℃, and then the dual-liquid acidic etching liquid is added. The copper ions in the dual-liquid acidic etching liquid first generate copper hydroxide, and then generate copper oxide precipitate, avoiding the generation of basic copper chloride in a neutral and weakly alkaline reaction system. In the process, copper oxide is generated in one step. Further, the generated copper oxide is washed with pure water until the tds of the washing filtrate is <50mg / L. In this washing process, a large amount of impurity ions, especially chloride ions, are removed from the surface of the copper oxide, obtaining pure copper oxide solid, laying a purity foundation for further preparation of electroplating-grade copper sulfate pentahydrate, and significantly reducing the impurity ion content in the subsequent production of copper sulfate solution. Further, through the reaction of copper oxide and sulfuric acid solution, a copper sulfate solution is generated, and then primary freeze crystallization is performed on the copper sulfate solution to obtain electroplating-grade copper sulfate pentahydrate. This method for preparing copper sulfate pentahydrate has the characteristics of simple process, low cost, green environmental protection, and high purity of copper sulfate pentahydrate.

[0018] The present application further limits the sodium hydroxide solution to 10wt%-12wt% sodium hydroxide solution, limits the volume ratio of the sodium hydroxide solution and the double-liquid type acidic etching solution to (2-2.5):1, and matches the temperature range of the sodium hydroxide solution at 75-85°C, so as to ensure that the sodium hydroxide solution can fully react with the double-liquid type acidic etching solution to generate copper oxide in one step, ensure the purity of the copper oxide, and avoid the doping of copper hydroxide in the copper oxide, especially, limiting the volume ratio of the sodium hydroxide solution and the double-liquid type acidic etching solution to (2-2.5):1, not only avoids the generation of basic copper chloride due to too little sodium hydroxide, but also avoids the waste of reagents and the too high pH value of the solution due to too much sodium hydroxide, further saving the production cost and reducing the residual of chloride ions.

[0019] Preferably, the method for preparing copper sulfate pentahydrate by the double-liquid type acidic etching solution further comprises step 3: preparing high-purity reagent grade copper sulfate pentahydrate crystals.

[0020] Step 3-1: taking the electroplating grade copper sulfate pentahydrate obtained in step 2, dissolving in pure water to obtain a copper sulfate solution, and performing secondary freezing crystallization on the copper sulfate solution to obtain a secondary cooling copper sulfate solution and copper sulfate pentahydrate crystals, wherein the copper sulfate pentahydrate crystals are high-purity reagent grade copper sulfate pentahydrate crystals.

[0021] Step 3-2: the secondary cooling copper sulfate solution is circulated back to step 3-1 and is used to dissolve the electroplating grade copper sulfate pentahydrate obtained in step 2 together with pure water.

[0022] In the above technical solution, the purity of the copper sulfate pentahydrate crystals is further improved by performing secondary freezing crystallization on the electroplating grade copper sulfate pentahydrate, and high-purity reagent grade copper sulfate pentahydrate crystals are obtained.

[0023] The present application also uses the secondary cooling copper sulfate solution to dissolve the electroplating grade copper sulfate pentahydrate by recycling the secondary cooling copper sulfate solution, further reduces the production cost, reduces the production waste, and achieves the purpose of environmental protection.

[0024] Preferably, step 1 in the method for preparing copper sulfate pentahydrate by the double-liquid type acidic etching solution further comprises step 1-3: performing secondary filtration on the primary filtrate obtained in step 1-1 by a plate and frame filter press under a pressure of 0.1-0.5 mps to obtain a secondary filtrate and crude copper oxide solids.

[0025] In the above technical solution, the present application further extracts the copper oxide solids in the primary filtrate by further performing plate and frame filter pressing on the primary filtrate, more fully utilizes the copper ions in the double-liquid type acidic etching solution, reduces the production waste, and saves the production cost.

[0026] The secondary filtrate of the application is mainly sodium chloride, which can be used in other industrial production, further saving the production cost and realizing the recycling of resources.

[0027] Preferably, step 2 in the method for preparing copper sulfate pentahydrate from the dual-liquid type acid etching liquid further comprises step 2-3: circulating the primary cooled copper sulfate solution back to step 2-1 to dissolve the pure copper oxide solid obtained in step 1.

[0028] In the above technical solution, the primary cooled copper sulfate solution is recycled to dissolve copper oxide, further reducing production cost and waste, and achieving the purpose of environmental protection.

[0029] Preferably, the copper ion concentration in the reaction system of step 2-1 is controlled within 130-150 g / L, the sulfate ion concentration in the reaction system of step 2-1 is controlled within 200-240 g / L, and the temperature of the reaction system in step 2-1 is controlled within 70-75℃.

[0030] In the above technical solution, by controlling the copper ion concentration in the reaction system of step 2-1 within 130-150 g / L, the sulfate ion concentration within 200-240 g / L, and the temperature of the reaction system within 70-75℃, the solubility of copper sulfate can be maximized, the yield of copper sulfate pentahydrate in the subsequent primary freezing crystallization process can be maximized, the yield of copper sulfate pentahydrate can be ensured, the production efficiency can be improved, and the production cost can be saved.

[0031] Preferably, the temperature of the primary freezing crystallization is 0-5℃, and the primary freezing crystallization time is 4-5h.

[0032] In the above technical solution, by limiting the temperature of the primary freezing crystallization to 0-5℃ and the primary freezing crystallization time to 4-5h, the copper sulfate pentahydrate is more likely to crystallize and precipitate, further promoting the formation of copper sulfate pentahydrate and reducing the adhesion of impurities.

[0033] Preferably, the copper ion concentration in the copper sulfate solution in step 3-1 is controlled within 130-150 g / L, the temperature of the copper sulfate solution in step 3-1 is controlled within 70-75℃, the temperature of the secondary freezing crystallization in step 3-1 is 0-5℃, and the secondary freezing crystallization time is 4-5h.

[0034] In the above technical solution, by limiting the copper ion concentration in the copper sulfate solution to 130-150 g / L and by controlling the temperature of the copper sulfate solution to 70℃-75℃, the solubility of copper sulfate can be maximized, the yield of copper sulfate pentahydrate can be maximized in the subsequent secondary freeze crystallization process, the yield of copper sulfate pentahydrate can be further guaranteed, the production efficiency can be improved, and the production cost can be saved.

[0035] Preferably, the purity of the high-purity reagent-grade copper sulfate pentahydrate crystals obtained in step 3 is above 99.5%.

[0036] In summary, compared with the prior art, this application has at least one of the following beneficial technical effects:

[0037] 1. The method for preparing copper sulfate pentahydrate using the two-component acidic etching solution of this application produces copper sulfate pentahydrate with high purity and very low impurity content, especially chloride ion content.

[0038] 2. The production process is environmentally friendly and simple, with low equipment investment and operating costs, which is conducive to large-scale industrial production.

[0039] 3. This application has a high resource utilization rate and realizes the recycling of resources. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0041] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0042] This application has discovered through research that by limiting the concentration of sodium hydroxide solution to 10wt% to 12wt% and the volume ratio of sodium hydroxide solution to two-component acidic etching solution to (2 to 2.5): 1, heating the sodium hydroxide solution to between 75°C and 85°C, and reacting the sodium hydroxide solution with the two-component acidic etching solution for 2 to 3 hours, copper oxide solid can be generated in one step. After washing and centrifugation, most of the chloride ions can be removed, resulting in pure copper oxide. This application has found that the chloride ion concentration in the copper sulfate solution obtained after reacting such pure copper oxide with sulfuric acid solution is less than 500 mg / L, which can significantly reduce the residual chloride ion content in the prepared pentahydrate copper sulfate.

[0043] According to some embodiments of this application, the concentration of sodium hydroxide solution in step 1-1 is 10wt% to 12wt%, for example, the concentration can be selected as 10wt%, 11wt%, 12wt%, etc.

[0044] According to some embodiments of the present application, the temperature of the sodium hydroxide solution in step 1-1 ranges from 75℃ to 85℃, for example, the optional temperature is 75℃, 77℃, 80℃, 82℃, 85℃, etc.

[0045] According to some embodiments of the present application, the volume ratio of the sodium hydroxide solution and the double-liquid type acidic etching solution in step 1-1 is (2-2.5):1, for example, the optional volume ratio is 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, etc.

[0046] According to some embodiments of the present application, the reaction time in step 1-1 is 2-3h, for example, the optional time is 2h, 2.5h, 3h, etc.

[0047] According to some embodiments of the present application, the centrifugal method in step 1-2 is high-speed centrifugation, and the separation factor is 1000-1200, for example, the optional separation factor is 1000, 1100, 1200, etc.

[0048] According to some embodiments of the present application, the washing method in step 1-2 is to wash the crude copper oxide with pure water with tds<5mg / L until the tds of the washing filtrate is <50mg / L.

[0049] According to some embodiments of the present application, the first-stage filtrate in step 1-3 is subjected to secondary filtration by a plate-and-frame filter press under a pressure of 0.1-0.5mps, for example, the optional pressure is 0.1mps, 0.2mps, 0.3mps, 0.4mps, 0.5mps, etc.

[0050] According to some embodiments of the present application, the sulfuric acid in step 2-1 can be a sulfuric acid solution or 98wt% concentrated sulfuric acid, but the amount added should be appropriate to control the sulfate ion concentration of the reaction system in step 2-1 within the range of 200-240g / L.

[0051] According to some embodiments of the present application, the temperature of the reaction system in step 2-1 is controlled within 70℃-75℃ to ensure that the copper sulfate has good solubility, for example, the optional temperature is 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, etc.

[0052] According to some embodiments of the present application, the copper ion concentration in the reaction system in step 2-1 is controlled within the range of 130-150g / L to maximize the precipitation of copper sulfate pentahydrate in subsequent freezing crystallization, for example, the applicable concentration is 130g / L, 135g / L, 140g / L, 145g / L, 150g / L, etc.

[0053] According to some embodiments of the present application, the sulfate ion concentration in the reaction system in step 2-1 is controlled in the range of 200-240 g / L, so as to maximize the precipitation of copper sulfate pentahydrate in the subsequent freeze crystallization, for example, the applicable concentration is 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, etc.

[0054] According to some embodiments of the present application, the first freeze crystallization in step 2-2 is to deliver the copper sulfate solution to a crystallization kettle, and the temperature of the crystallization kettle is in the range of 0-5°C, for example, the optional temperature range of the crystallization kettle is 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, etc.

[0055] According to some embodiments of the present application, the time range of the first freeze crystallization in step 2-2 is 4-5 h, for example, the optional freeze crystallization time range is 4 h, 4.5 h, 5 h, etc.

[0056] According to some embodiments of the present application, the first cooling copper sulfate solution in step 2-3 is circulated back to step 2-1, and then the pure copper oxide solid is dissolved, and then the sulfuric acid solution is delivered to control the temperature of the reaction system to 70-75°C, the copper ion concentration is controlled in the range of 130-150 g / L, and the sulfate ion concentration is controlled in the range of 200-240 g / L.

[0057] According to some embodiments of the present application, the system temperature of the copper sulfate solution in step 3-1 is controlled in the range of 70-75°C, so as to ensure the maximum solubility of copper sulfate, for example, the optional temperature is 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, etc.

[0058] According to some embodiments of the present application, the copper ion concentration of the copper sulfate solution in step 3-1 is controlled in the range of 130-150 g / L, so as to maximize the precipitation of copper sulfate pentahydrate in the subsequent freeze crystallization, for example, the applicable concentration is 130 g / L, 135 g / L, 140 g / L, 145 g / L, 150 g / L, etc.

[0059] According to some embodiments of the present application, the second freeze crystallization in step 3-1 is to deliver the copper sulfate solution to a crystallization kettle, and the temperature of the crystallization kettle is in the range of 0-5°C, for example, the optional temperature range of the crystallization kettle is 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, etc.

[0060] According to some embodiments of the present application, the time range of the second freeze crystallization in step 3-1 is 4-5 h, for example, the optional freeze crystallization time range is 4 h, 4.5 h, 5 h, etc.

[0061] According to some embodiments of the present application, the secondary cooling copper sulfate solution in step 3-2 is circulated back to step 3-1 to dissolve the electroplating grade copper sulfate pentahydrate with pure water, the temperature of the reaction system is controlled at 70-75℃, and the copper ion concentration is controlled within the range of 130-150g / L.

[0062] Example 1

[0063] A method for preparing copper sulfate pentahydrate by a double-liquid type (hydrochloric acid + sodium chlorate system) acidic etching solution, comprising the following steps:

[0064] Step 1: Preparation of pure copper oxide solid.

[0065] Step 1-1: 15000L of 10wt% sodium hydroxide solution is heated to 75℃, 6000L of double-liquid type acidic etching solution is added, and after 2h of reaction, primary filtration (high-speed centrifugation, separation factor 1000) is performed to obtain primary filtrate and crude copper oxide solid.

[0066] Step 1-2: The crude copper oxide solid is washed and centrifuged (high-speed centrifugation, separation factor 1000), washed with pure water with tds<5mg / L until the tds of the washing filtrate is <50mg / L to obtain pure copper oxide solid.

[0067] Step 1-3: The primary filtrate obtained in step 1-1 is subjected to secondary filtration by a plate and frame filter press under a pressure of 0.5mps to obtain secondary filtrate and crude copper oxide solid, the secondary filtrate is sodium chloride solution which can be used for other industrial production, and the crude copper oxide solid obtained in step 1-1 is mixed with the crude copper oxide solid obtained in step 1-1 and then subjected to step 1-2 to obtain pure copper oxide solid.

[0068] Step 2: Preparation of electroplating grade copper sulfate pentahydrate.

[0069] Step 2-1: An appropriate amount of 98wt% concentrated sulfuric acid and pure water are added to the pure copper oxide solid obtained in step 1, and the two react to obtain a copper sulfate solution, the amount of sulfuric acid solution is controlled to ensure that the pure copper oxide solid is completely dissolved, the temperature of the reaction system is controlled at 70℃, the copper ion concentration is controlled within the range of 130-150g / L, and the sulfate ion concentration is controlled within the range of 200-240g / L.

[0070] Step 2-2: The copper sulfate solution obtained in step 2-1 is subjected to primary freezing crystallization, the freezing crystallization temperature is 5℃, and the freezing crystallization time is 4h to obtain primary cooling copper sulfate solution and electroplating grade copper sulfate pentahydrate.

[0071] Step 2-3: The primary cooling copper sulfate solution is circulated back to step 2-1 to dissolve the pure copper oxide solid obtained in step 1.

[0072] Step 3: Preparation of high-purity reagent grade copper sulfate pentahydrate crystals.

[0073] Step 3-1: Take the electroplating grade copper sulfate pentahydrate obtained in Step 2, control the reaction system temperature to be 70°C, add pure water to dissolve, control the amount of pure water, obtain a copper sulfate solution with a copper ion concentration in the range of 130-150 g / L, and perform secondary cooling crystallization on the copper sulfate solution, the temperature of the cooling crystallization is 5°C, and the time of the cooling crystallization is 4 h, to obtain a secondary cooling copper sulfate solution and high-purity reagent grade copper sulfate pentahydrate crystals.

[0074] Step 3-2: The secondary cooling copper sulfate solution is circulated back to Step 3-1 and dissolved with the electroplating grade copper sulfate pentahydrate obtained in Step 2 and pure water to obtain a copper sulfate solution with a copper ion concentration in the range of 130-150 g / L.

[0075] Example 2

[0076] The electroplating grade copper sulfate pentahydrate obtained in Step 2 of Example 1 was subjected to quality detection, and the results are shown in Table 1.

[0077] Table 1:

[0078]

[0079] As can be seen from Table 1, the method for preparing copper sulfate pentahydrate from the dual-liquid type acidic etching solution according to the present application only needs one cooling crystallization to make the generated copper sulfate pentahydrate be electroplating grade copper sulfate pentahydrate.

[0080] The chloride content of the electroplating grade copper sulfate pentahydrate according to the present application is only 0.002%, and the residual amount of chloride is extremely low.

[0081] Example 3

[0082] The high-purity reagent grade copper sulfate pentahydrate obtained in Step 3 of Example 1 was subjected to quality detection, and the results are shown in Table 2.

[0083] Table 2:

[0084]

[0085]

[0086]

[0087] As can be seen from Table 2, the method for preparing copper sulfate pentahydrate from the dual-liquid type acidic etching solution according to the present application only needs two cooling crystallizations to make the generated copper sulfate pentahydrate be high-purity reagent grade copper sulfate pentahydrate, which reduces the equipment investment cost and production operation cost and is suitable for large-scale industrial production.

[0088] The embodiments are only illustrative of the present application, and are not intended to limit the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing copper sulfate pentahydrate from a two-liquid type acidic etching solution, characterized by, The method for preparing copper sulfate pentahydrate from the double-liquid type acidic etching solution comprises the following steps: Step 1: preparing pure copper oxide solid; Step 1-1: adding the double-liquid type acidic etching solution into the sodium hydroxide solution with a temperature of 75-85 DEG C, and after 2-3 hours of reaction, performing primary filtration to obtain primary filtrate and crude copper oxide solid; Step 1-2: washing and centrifuging the crude copper oxide solid to obtain pure copper oxide solid; Step 1-3: performing secondary filtration on the primary filtrate obtained in step 1-1 by using a plate and frame filter press under a pressure of 0.1-0.5 mps to obtain secondary filtrate and crude copper oxide solid; Step 2: preparing electroplating grade copper sulfate pentahydrate; Step 2-1: adding a proper amount of sulfuric acid and pure water into the pure copper oxide solid obtained in step 1 to obtain copper sulfate solution; Step 2-2: performing primary refrigeration crystallization on the copper sulfate solution obtained in step 2-1, the temperature of the primary refrigeration crystallization is 0-5 DEG C, and the crystallization lasts for 4-5 hours to obtain primary cooled copper sulfate solution and copper sulfate pentahydrate crystals, and the copper sulfate pentahydrate crystals are electroplating grade copper sulfate pentahydrate; Step 2-3: circulating the primary cooled copper sulfate solution back to step 2-1 to dissolve the pure copper oxide solid obtained in step 1; Step 3: preparing high-purity reagent grade copper sulfate pentahydrate crystals; Step 3-1: dissolving the electroplating grade copper sulfate pentahydrate obtained in step 2 in pure water to obtain copper sulfate solution, and performing secondary refrigeration crystallization on the copper sulfate solution, the temperature of the secondary refrigeration crystallization is 0-5 DEG C, and the crystallization lasts for 4-5 hours to obtain secondary cooled copper sulfate solution and copper sulfate pentahydrate crystals, and the copper sulfate pentahydrate crystals are high-purity reagent grade copper sulfate pentahydrate crystals; Step 3-2: circulating the secondary cooled copper sulfate solution back to step 3-1 to dissolve the electroplating grade copper sulfate pentahydrate obtained in step 2 together with pure water; In the method for preparing copper sulfate pentahydrate from the double-liquid type acidic etching solution, the sodium hydroxide solution in step 1-1 is 10-12 wt% sodium hydroxide solution; The volume ratio of the sodium hydroxide solution to the double-liquid type acidic etching solution is (2-2.5):1; The primary filtration refers to high-speed centrifugation in the range of separation factor 1000-1200; The washing refers to washing with pure water with tds less than 5 mg / L until the tds of the washing filtrate is less than 50 mg / L; The purity of the high-purity reagent grade copper sulfate pentahydrate crystals obtained in step 3 is more than 99.5%.

2. The method of claim 1, wherein the method of preparing copper sulfate pentahydrate from a two-solution type acidic etching solution is characterized by, The copper ion concentration in the reaction system in step 2-1 is controlled within 130-150 g / L, the sulfate ion concentration in the reaction system in step 2-1 is controlled within 200-240 g / L, and the temperature of the reaction system in step 2-1 is controlled within 70-75 DEG C.

3. The method of claim 1, wherein the method of preparing copper sulfate pentahydrate from a dual-solution type acidic etching solution is characterized by, The copper ion concentration in the copper sulfate solution in step 3-1 is controlled within 130-150 g / L, and the temperature of the copper sulfate solution in step 3-1 is controlled within 70-75 DEG C.

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