阅读说明：本技术 一种试剂级二水合氯化铜晶体的制备方法 (Preparation method of reagent-grade copper chloride dihydrate crystal ) 是由 高东瑞 周国立 于 2020-12-30 设计创作，主要内容包括：本发明属于二水合氯化铜晶体的制备方法技术领域,提供了一种试剂级二水合氯化铜晶体的制备方法,该方法先对线路板酸性蚀刻废液进行预处理,然后用萃取剂萃取酸性蚀刻废液中的氯化铜,萃余液补充添加剂后调配成再生蚀刻液回用线路板蚀刻生产线,萃取剂携带的氯化铜用纯水反萃得到氯化铜溶液,氯化铜溶液通过深度净化除杂、调整pH值、蒸发、浓缩、冷却结晶、离心分离、低温干燥等工序得到试剂级二水合氯化铜晶体。利用线路板酸性蚀刻废液生产试剂级二水合氯化铜晶体,在降低试剂级二水合氯化铜晶体生产成本的同时也避免了蚀刻废液外运处置二次污染环境的风险,具有良好的生态环境与经济效益。(The invention belongs to the technical field of a preparation method of copper chloride dihydrate crystals, and provides a preparation method of reagent-grade copper chloride dihydrate crystals. The reagent-grade copper chloride dihydrate crystal is produced by utilizing the acidic etching waste liquid of the circuit board, the production cost of the reagent-grade copper chloride dihydrate crystal is reduced, the risk of secondary environmental pollution caused by outward transportation and disposal of the etching waste liquid is avoided, and the ecological environment and economic benefits are good.)

1. A preparation method of reagent-grade copper chloride dihydrate crystals is characterized by comprising the following steps: the method comprises the following steps:

step one, pretreatment of acidic etching waste liquid: filtering the etching waste liquid overflowing from the printed circuit board acidic etching line, collecting the etching waste liquid to an oxidant destruction reactor, and adding low-valence copper to perform a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain a pretreated etching waste liquid with acidity of 2.0-2.5 mol/L;

step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain raffinate with copper ion content of 5-10g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is (2-3): 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, and the volume fraction of the pyridine carboxylic ester is 10-35%;

step three, deeply purifying the copper chloride solution: adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step for impurity removal, and then filtering to obtain a copper chloride purified solution;

step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the step three, then cooling, crystallizing, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at low temperature to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and (4) mixing the copper chloride mother liquor obtained in the step four with the raffinate obtained in the step two, supplementing additives, and then preparing into a regenerated acidic etching solution for recycling to an acidic etching production line.

2. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the low-valence copper in the first step is one of metal copper powder, metal copper sheet and cuprous chloride and cuprous oxide.

3. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the oxidation-reduction potential of the etching waste liquid in the first step is 450-500 mV.

4. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the filtration treatment in the first step is carried out by adopting one mode of a folding filter element with the aperture of 0.1-5 mu m, a cotton core and a silicon carbide filter element.

5. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the method for deeply purifying the copper chloride solution in the third step comprises the following steps: firstly heating a copper chloride solution to 40-80 ℃, adding 30% hydrogen peroxide according to the volume ratio of 1-5% to react for 30-60min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding 1-5% of activated carbon according to the volume ratio to react for 30-60min, and finally filtering the copper chloride solution after impurity removal to obtain the deeply purified copper chloride solution.

6. The method for preparing reagent-grade copper chloride dihydrate crystal according to claim 1 or 5, characterized in that: the oxygen-containing copper compound in the third step is one of basic copper chloride, copper carbonate, copper hydroxide and copper oxide.

7. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: in the fourth step, the temperature of the copper chloride solution is reduced and evaporated to 70-90 ℃, the cooling crystallization temperature is 26-42 ℃, and the drying temperature is 60-70 ℃.

8. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the additive in the fifth step is a mixture of sodium chloride and hydrogen peroxide, and the content of the sodium chloride is 100-200 g/L.

9. The method for preparing reagent-grade copper chloride dihydrate crystals according to claim 1, characterized in that: the oxidation-reduction potential of the regenerated acidic etching solution in the fifth step is 500-550mV, and the acidity of the regenerated acidic etching solution is 2.0-2.5 mol/L.

Technical Field

The invention relates to the technical field of preparation methods of copper chloride dihydrate crystals, in particular to a preparation method of reagent-grade copper chloride dihydrate crystals.

Background

In the life of people, all automatically controlled products, such as spacecrafts, airplanes, high-speed rails, automobiles and steamships, computers, mobile phones and even pedometers carried by a plurality of people, need to be transmitted by a circuit board (PCB) to achieve automatic control. The PCB is a support body of electronic product components and is the most basic hardware carrier of the current information society, the PCB industry is the pillar industry of the Chinese electronic information industry, and the growth rate of the PCB industry is the same as that of the electronic information industry. PCB production processes have improved greatly over decades of PCB production practices. The method for preparing the circuit diagram of the PCB still uses a subtractive process, namely the copper-clad plate is manufactured into the circuit diagram through the working procedures of cutting, pasting, pattern transferring, developing, inner layer etching, film stripping and the like, and then the circuit board production is completed through the working procedures of pressing, drilling, copper electroplating, outer layer manufacturing and the like. In the inner layer etching step, an acid etching method is adopted, the oxidation-reduction potential and the copper ion concentration in the etching solution are kept in a certain area, the etching rate is maintained, an oxidant and hydrochloric acid are continuously added in the etching process, meanwhile, the overflowing etching solution is changed into etching waste liquid, the main components of the acid etching waste liquid are copper chloride and hydrochloric acid (containing about 10% of copper), according to the fact that environmental protection workers consider the facts that the situation is equal to 2018, in 3 months, in volume 8, 2 of environmental engineering journal, a paper, namely, current situation and management strategy research of treating and utilizing industry of copper-containing etching waste liquid in Jiangsu province is published, and a PCB enterprise only in Jiangsu province in 2016 is claimed to generate 52 million tons of PCB copper-containing etching waste liquid. The annual production amount of the copper-containing waste liquid of the PCB in China is more than million tons, the copper-containing waste liquid is more than 10 million tons, and on the other hand, the annual demand amount of the electrolytic copper of the domestic circuit board (PCB) industry for phosphor copper balls, copper oxide and copper sulfate is more than 10 million tons compared with that of metal copper.

At present, PCB copper-containing waste liquid is generally sold to enterprises with hazardous waste treatment qualification by circuit board enterprises at a lower price for treatment, the hazardous waste treatment enterprises comprehensively recycle the collected etching waste liquid and use copper in the etching waste liquid to prepare copper salt products, and the waste water is subjected to harmless treatment and then is discharged after reaching the standard. The invention CN103693673B granted by Chinese patent discloses a method for producing electroplating-grade copper sulfate by using acidic copper-containing etching waste liquid, the method generates high-purity copper oxide by reacting clear water or copper oxide production mother liquid or the copper sulfate production mother liquid with the acidic copper-containing etching waste liquid and mixed alkali liquor, the temperature of a reaction system is controlled to be 70-90 ℃, the pH value is 8.5-9, the mixed alkali liquor is formed by mixing strong base, weak acid salt and strong base, and the mass ratio is 1:6-1: 8; and adding the prepared high-purity copper oxide and concentrated sulfuric acid into clear water or plating-grade copper sulfate production mother liquor, and controlling the pH value of the reaction to be 0.1-3 to prepare plating-grade copper sulfate. Although the process can prepare the electroplating-grade copper sulfate (high-purity copper sulfate still needs further purification treatment to reduce impurities such as sodium ions) compared with the prior art that the acidic etching waste liquid is neutralized by ammonia water, no ammonia nitrogen is introduced, but the process still has a large amount of high-salt waste water (sodium chloride) to be discharged, and the environment pollution can be caused by improper treatment. In view of the influence of the traditional process on the environment, the on-line recycling and regenerating process of the acidic etching waste liquid is developed in the industry in recent years.

Chinese granted utility model patent CN202492581U discloses a device for recycling acidic etching solution for printed circuit boards, which comprises an etching waste liquid storage tank, a composite diaphragm electrolytic tank, an etching solution transfer tank and a regenerated etching solution preparation tank, wherein the composite diaphragm electrolytic tank is divided into an anode chamber and a cathode chamber by a composite diaphragm; one end of the etching solution transfer groove is communicated with the etching cylinder, and the other end of the etching solution transfer groove is communicated with the cathode chamber; one end of the etching waste liquid storage tank is communicated with the etching cylinder, and the other end of the etching waste liquid storage tank is communicated with the cathode chamber; wherein the anode chamber is communicated with the etching cylinder by a regenerative etching solution tank. The device solves the technical problem that an oxidant is additionally added to oxidize cuprous ions in the prior art, reduces the generation cost, does not add impurities into the regenerated etching solution, and ensures the consistency of the regenerated etching solution and the fresh etching solution; the device can recycle cathode copper with high purity, no waste water is discharged, clean production of an etching process is realized, the device can recycle acidic etching solution, but chlorine generated in an anode chamber of a diaphragm electrolytic cell is difficult to be completely absorbed, a common treatment method at present uses liquid caustic soda for absorption, the cost of the liquid caustic soda is high, even though the chlorine is absorbed by multiple stages, the chlorine still has a leakage risk, the cathode copper recycled by the device has high purity but poor physical performance, can reach the standard of industrial application after being treated by a smelting furnace again, and the selling price of the cathode copper is low.

Copper chloride dihydrate is a crystal of a blue-green orthorhombic system, is mainly used as an electroplating additive, a chemical reaction catalyst, a deodorizing, desulfurizing and purifying agent in the petroleum industry, a printing and dyeing mordant, an oxidant of aniline dye and the like, and the production method is mainly a hydrochloric acid method, namely, a certain amount of copper oxide is gradually added into a reactor containing hydrochloric acid while stirring for acidolysis reaction to generate copper chloride, and then the copper chloride is evaporated, concentrated, cooled, crystallized, centrifugally separated and dried to obtain a finished product of the copper chloride.

Chinese patent CN110980794A discloses a method for preparing SiO₂A method for preparing high-purity copper chloride dihydrate by regulating and controlling copper-containing sludge. Drying, grinding and sieving the copper-containing sludge, adding SiO into the copper-containing sludge according to a certain proportion₂And hydrochloric acid, and stirring uniformly; roasting the obtained mixture in a flowing air atmosphere at the temperature of 700-1200 ℃, and condensing the product after volatilization to obtain CuCl₂·2H₂And O. The method can be used for recovering 95-97% of copper in the copper-containing sludge, and the purity of the prepared product is about 95%. The method has simple process, small secondary pollution and high product application value, is a great breakthrough in the technical field of heavy metal waste residue recycling, overcomes the problems of complex process, high cost, large secondary pollution and the like of the copper extraction technology of the copper-containing sludge, provides a new idea for preparing copper chloride dihydrate and recovering heavy metals from other heavy metal waste residues, and has remarkable environmental and economic benefits, but the equipment investment is obviousThe product purity is only about 95 percent, and the product purity can not reach the standard of reagent-grade copper chloride dihydrate.

Disclosure of Invention

In order to solve the problems, the invention provides a preparation method of reagent-grade copper chloride dihydrate crystals, which reduces the production cost of the reagent-grade copper chloride dihydrate crystals, avoids the risk of secondary environmental pollution caused by outward transportation and disposal of etching waste liquid, and has good ecological environment and economic benefit, and the contents of the preparation method are as follows:

the invention aims to provide a preparation method of reagent-grade copper chloride dihydrate crystals, which has the technical points that: the method comprises the following steps:

step one, pretreatment of acidic etching waste liquid: filtering the etching waste liquid overflowing from the printed circuit board etching line, collecting the etching waste liquid to an oxidant breaking reactor, and adding metal copper to perform a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain pretreated etching waste liquid with acidity of 2.0-2.5 mol/L;

step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain raffinate with copper ion content of 5-10g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is (2-3): 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, and the volume fraction of the pyridine carboxylic ester is 10-35%;

step three, deeply purifying the copper chloride solution: adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step for impurity removal, and then filtering to obtain a copper chloride purified solution;

step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the step three, then cooling, crystallizing, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at low temperature to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and (4) mixing the copper chloride mother liquor obtained in the step four with the raffinate obtained in the step two, supplementing additives, and then preparing into a regenerated acidic etching solution for recycling to an acidic etching production line.

In an embodiment of the invention, the low-valence copper in the first step of the preparation method of the reagent-grade copper chloride dihydrate crystal is one of copper metal powder, copper metal sheet and cuprous chloride and cuprous oxide.

In an embodiment of the invention, in the step one of the preparation method of the reagent-grade copper chloride dihydrate crystal, the oxidation-reduction potential of the pretreated etching waste liquid is 450-500 mV.

In an embodiment of the invention, in the first step of the preparation method of the reagent-grade copper chloride dihydrate crystal, the filtration treatment is performed by using one of a folded filter element with a pore size of 0.1-5 μm, a cotton core and a silicon carbide filter element.

In an embodiment of the present invention, the method for deeply purifying the copper chloride solution in the third step of the preparation method of the reagent-grade copper chloride dihydrate crystal comprises: firstly heating a copper chloride solution to 40-80 ℃, adding 30% hydrogen peroxide according to the volume ratio of 1-5% to react for 30-60min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding 1-5% of activated carbon according to the volume ratio to react for 30-60min, and finally filtering the copper chloride solution after impurity removal to obtain the deeply purified copper chloride solution.

In an embodiment of the invention, in the third step of the preparation method of the reagent-grade copper chloride dihydrate crystal, the oxygen-containing copper compound is one of basic copper chloride, copper carbonate, copper hydroxide and copper oxide.

In an embodiment of the present invention, in the fourth step of the preparation method of the reagent-grade copper chloride dihydrate crystal, the temperature of the copper chloride solution is evaporated under reduced pressure and is 70-90 ℃, the cooling crystallization temperature is 26-42 ℃, and the drying temperature is 60-70 ℃.

In an embodiment of the invention, in the fifth step of the preparation method of the reagent-grade copper chloride dihydrate crystal, the additive is a mixture of sodium chloride and hydrogen peroxide, and the content of the sodium chloride is 100-200 g/L.

In an embodiment of the invention, in the fifth step of the preparation method of the reagent-grade copper chloride dihydrate crystal, the oxidation-reduction potential of the regenerated acidic etching solution is 500-550mV, and the acidity of the regenerated acidic etching solution is 2.0-2.5 mol/L.

Compared with the prior art, the invention has the beneficial effects that:

according to the preparation method of the reagent-grade copper chloride dihydrate crystal, the reagent-grade copper chloride dihydrate crystal is prepared by utilizing the circuit board acidic etching waste liquid, the production flow is short, the production cost is low, the product purity is high, the regeneration of the circuit board acidic etching waste liquid is realized while the reagent-grade copper chloride dihydrate crystal is produced at low cost, the risk of secondary environmental pollution caused by the outward transportation and disposal of the etching waste liquid is avoided, and the preparation method has good ecological environment and economic benefits.

Drawings

FIG. 1 is a flow chart of a method for preparing reagent-grade copper chloride dihydrate crystals according to the present invention.

Detailed Description

A preparation method of reagent-grade copper chloride dihydrate crystals comprises the following steps:

step one, pretreatment of acidic etching waste liquid: the waste etching solution overflowing from the printed circuit board etching line is filtered and collected to an oxidant breaking reactor, and the filtering treatment is carried out by adopting one mode of a folding filter element with the aperture of 0.1-5 mu m, a cotton core and a silicon carbide filter element. Adding low-valence copper (one of metal copper powder, metal copper sheet and cuprous chloride and cuprous oxide) to perform a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain a pretreated etching waste liquid with the acidity of 2.0-2.5mol/L, wherein the oxidation-reduction potential of the pretreated etching waste liquid is 450-500mV, the purpose of reducing the oxidation-reduction potential is to prevent residual oxidant in the etching waste liquid from damaging the extractant to cause emulsification, and the purpose of filtering is to prevent membrane slag and the like in the etching liquid from polluting the extractant to cause difficulty in layering of an organic phase and a water phase.

Step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain raffinate with copper ion content of 5-10g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is (2-3): 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, the volume fraction of the pyridine carboxylic ester is 10-35%, and the pyridine carboxylic ester is preferably AcorgaDS5443(CLX 50).

Step three, deeply purifying the copper chloride solution: and (3) purifying the copper chloride solution to remove residual trace extraction oil, iron ions and the like in the solution, adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step to remove impurities, and filtering to obtain a copper chloride purified solution. The method for deeply purifying the copper chloride solution comprises the following steps: firstly heating a copper chloride solution to 40-80 ℃, adding 30% hydrogen peroxide according to the volume ratio of 1-5% for reaction for 30-60min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding 1-5% of activated carbon according to the volume ratio for reaction for 30-60min, and finally filtering the copper chloride solution after impurity removal to obtain the copper chloride solution after deep purification, wherein the oxygen-containing copper compound is one of basic copper chloride, copper carbonate, copper hydroxide and copper oxide.

Step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the step three at the temperature of 70-90 ℃, then cooling and crystallizing at the temperature of 26-42 ℃, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at the temperature of 60-70 ℃ to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and mixing the copper chloride mother liquor obtained in the fourth step with the raffinate obtained in the second step, adding an additive to prepare a regenerated acidic etching solution with the oxidation-reduction potential of 500-550mV and the acidity of 2.0-2.5mol/L, wherein the additive is a mixture of sodium chloride and hydrogen peroxide, the content of the sodium chloride is 100-200g/L, and recycling the regenerated acidic etching solution to an acidic etching production line.

The technical solutions in the embodiments of the present invention will be clearly and completely described below so that those skilled in the art can better understand the advantages and features of the present invention, and thus the scope of the present invention will be more clearly defined. The embodiments described herein are only a few embodiments of the present invention, rather than all embodiments, and all other embodiments that can be derived by one of ordinary skill in the art without inventive faculty based on the embodiments described herein are intended to fall within the scope of the present invention.

In the preparation method of the reagent-grade copper chloride dihydrate crystal, the used raw material is production waste liquid used in a PCB etching process of a P Circuit Board (PCB) production enterprise, the copper content of the acidic etching waste liquid is 160g/L, the hydrochloric acid content is 2.0-2.5mol/L, and the hydrogen peroxide is hydrogen peroxide with the mass concentration of 30 wt%.

Example 1

A preparation method of reagent-grade copper chloride dihydrate crystals comprises the following steps:

step one, pretreatment of acidic etching waste liquid: and collecting the etching waste liquid overflowing from the printed circuit board etching line to an oxidant destruction reactor after filtering treatment, wherein the filtering treatment adopts a folding filter element with the aperture of 0.1 mu m. And adding copper powder to perform a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain the pretreated etching waste liquid with the acidity of 2.5mol/L, wherein the oxidation-reduction potential of the pretreated etching waste liquid is 450 mV.

Step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain a raffinate with a copper ion content of 10g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is 3: 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, and the volume fraction of the pyridine carboxylic ester is 35%.

Step three, deeply purifying the copper chloride solution: adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step for impurity removal, and then filtering to obtain a copper chloride purified solution. The method for deeply purifying the copper chloride solution comprises the following steps: firstly heating a copper chloride solution to 40 ℃, adding hydrogen peroxide with the mass concentration of 30% according to the volume ratio of 1% for reaction for 60min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding active carbon according to the volume ratio of 2% for reaction for 60min, and finally filtering the copper chloride solution after impurity removal to obtain the copper chloride solution after deep purification, wherein the oxygen-containing copper compound is copper oxide.

Step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the third step at the temperature of 80 ℃ until the specific gravity is 1.32g/mg, then cooling and crystallizing at the temperature of 28 ℃, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at the temperature of 60 ℃ to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and (3) mixing the copper chloride mother liquor obtained in the fourth step with the raffinate obtained in the second step, adding an additive, and then preparing the mixture into a regenerated acidic etching solution with the oxidation-reduction potential of 500-500mV and the acidity of 2.0-2.5mol/L, wherein the additive is a mixture of sodium chloride and hydrogen peroxide, the content of the sodium chloride is 150g/L, and recycling the mixture to an acidic etching production line.

Example 2

A preparation method of reagent-grade copper chloride dihydrate crystals comprises the following steps:

step one, pretreatment of acidic etching waste liquid: and filtering the etching waste liquid overflowing from the printed circuit board etching line, collecting the etching waste liquid to an oxidant breaking reactor, wherein the filtering treatment is carried out by adopting a silicon carbide filter element with the aperture of 5 mu m, and carrying out a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain the pretreated etching waste liquid with the acidity of 2.1mol/L, and the oxidation-reduction potential of the pretreated etching waste liquid is 480 mV.

Step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain a raffinate with a copper ion content of 7g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is 2: 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, the volume fraction of the pyridine carboxylic ester is 15%, and the pyridine carboxylic ester is preferably AcorgaDS5443(CLX 50).

Step three, deeply purifying the copper chloride solution: adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step for impurity removal, and then filtering to obtain a copper chloride purified solution. The method for deeply purifying the copper chloride solution comprises the following steps: firstly heating a copper chloride solution to 80 ℃, adding hydrogen peroxide with the mass concentration of 30% according to the volume ratio of 5% for reaction for 30min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding active carbon according to the volume ratio of 5% for reaction for 40min, and finally filtering the copper chloride solution after impurity removal to obtain the copper chloride solution after deep purification, wherein the oxygen-containing copper compound is copper carbonate.

Step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the third step at the temperature of 70 ℃ until the specific gravity is 1.35g/mg, then cooling and crystallizing at the temperature of 40 ℃, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at the temperature of 70 ℃ to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and (3) mixing the copper chloride mother liquor obtained in the fourth step with the raffinate obtained in the second step, adding an additive, and blending to prepare a regenerated acidic etching solution with the oxidation-reduction potential of 520mV and the acidity of 2.4mol/L, wherein the additive is a mixture of sodium chloride and hydrogen peroxide, the content of the sodium chloride is 200g/L, and recycling the solution to an acidic etching production line.

Example 3

A preparation method of reagent-grade copper chloride dihydrate crystals comprises the following steps:

step one, pretreatment of acidic etching waste liquid: and filtering the waste etching solution overflowing from the printed circuit board etching line, and collecting the waste etching solution to an oxidant destruction reactor, wherein the filtering is performed by adopting a cotton core with the aperture of 0.5 mu m. Adding copper powder, and carrying out a reaction for reducing the oxidation-reduction potential of the etching waste liquid to obtain the pretreated etching waste liquid with the acidity of 2.0mol/L, wherein the oxidation-reduction potential of the pretreated etching waste liquid is 500 mV.

Step two, separating copper chloride in the acidic etching waste liquid: adding an extractant into the solution obtained in the first step for carrying out copper chloride extraction reaction to obtain a raffinate with a copper ion content of 5g/L and a loaded organic phase, carrying out back extraction on the loaded organic phase by using pure water to obtain a copper chloride solution and the extractant, wherein the volume ratio of the extractant to the etching waste liquid is 2.5: 1, the extractant is a mixture of pyridine carboxylic ester and sulfonated kerosene, the volume fraction of the pyridine carboxylic ester is 10%, and the pyridine carboxylic ester is preferably AcorgaDS5443(CLX 50).

Step three, deeply purifying the copper chloride solution: adding hydrogen peroxide, activated carbon and an oxygen-containing copper compound into the copper chloride solution obtained by the second treatment step for impurity removal, and then filtering to obtain a copper chloride purified solution. The method for deeply purifying the copper chloride solution comprises the following steps: firstly heating a copper chloride solution to 60 ℃, adding hydrogen peroxide with the mass concentration of 30% according to the volume ratio of 3% for reaction for 40min, then adding an oxygen-containing copper compound to adjust the pH value of the copper chloride solution to 2.0, then adding active carbon according to the volume ratio of 3% for reaction for 40min, and finally filtering the copper chloride solution after impurity removal to obtain the copper chloride solution after deep purification, wherein the oxygen-containing copper compound is copper hydroxide.

Step four, preparing copper chloride dihydrate crystals: carrying out reduced pressure evaporation concentration on the purified copper chloride solution obtained in the third step at the temperature of 90 ℃ until the specific gravity is 1.33g/mg, then cooling and crystallizing at the temperature of 35 ℃, carrying out centrifugal separation to obtain copper chloride crystals and copper chloride mother liquor, and further drying the copper chloride crystals at the temperature of 65 ℃ to obtain reagent-grade copper chloride dihydrate crystals;

step five, preparing the regenerated acidic etching solution: and (3) mixing the copper chloride mother liquor obtained in the fourth step with the raffinate obtained in the second step, adding an additive, and blending to prepare a regenerated acidic etching solution with the oxidation-reduction potential of 550mV and the acidity of 2.1mol/L, wherein the additive is a mixture of sodium chloride and hydrogen peroxide, the content of the sodium chloride is 200g/L, and recycling the solution to an acidic etching production line.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.