阅读说明：本技术 一种碱性蚀刻液循环再生方法 (Cyclic regeneration method of alkaline etching solution ) 是由 欧阳锋 邰康乾 龙正 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种碱性蚀刻液循环再生方法,所公开的碱性蚀刻液再生循环技术采用溶剂萃取-电解还原法,从失效蚀铜液中分离回收铜,同时通过补加药剂,使失效蚀铜液得到有效回收并循环使用。本发明公开的碱性蚀刻液循环再生方法具有操作可连续自动化、设备新颖、成本低的特点。(The invention discloses a method for recycling alkaline etching solution, which adopts a solvent extraction-electrolytic reduction method to separate and recover copper from invalid copper etching solution, and simultaneously supplements medicament to effectively recover and recycle the invalid copper etching solution. The method for recycling the alkaline etching solution disclosed by the invention has the characteristics of continuous and automatic operation, novel equipment and low cost.)

1. The method for recycling the alkaline etching solution is characterized by comprising the following steps of:

s1, extracting the alkaline etching waste liquid by using a solvent to obtain a copper-loaded oil phase and a first water phase;

s2, carrying out primary water washing on the copper-loaded oil phase to obtain a second oil phase and a second water phase;

s3, adding a back-extracting agent into the second oil phase to obtain a third oil phase and a third water phase;

s4, electrolyzing the third water phase, depositing copper ions in the third water phase, and exhausting oxygen to obtain an electrodeposited liquid and deposited copper;

s5, combining the third oil phase and the second water phase, and performing secondary washing on the combined mixed solution to obtain a fourth water phase and a fourth oil phase;

and S6, performing membrane treatment fine adjustment or adopting a reduced pressure distillation process on the fourth water phase, and adjusting the pH value to form an alkaline solution.

2. The method for recycling alkaline etching solution according to claim 1, further comprising combining the post-electrodeposition solution with the second oil and performing the stripping step in S3 again after the step S4.

3. The method according to claim 1, further comprising a step of adjusting the composition of the first aqueous phase after step S1, and adding ammonia and ammonium chloride to form a regenerated etching solution.

4. The method of claim 3, further comprising recycling Cu in the recycled etching solution²⁺、NH⁴⁺、Cl^-And measuring the plasma and the pH value, and determining the required added ammonia and ammonium chloride according to the measurement result so as to achieve the accurate control of the component adjustment.

5. The method for recycling alkaline etching solution according to claim 1, further comprising the step of re-performing the fourth oil phase in S1-S5 after the step of S5.

6. The method for recycling alkaline etching solution according to claim 1, wherein the step S6 of using a reduced pressure distillation process specifically includes concentrating the fourth aqueous phase under reduced pressure to obtain distilled water containing hydrochloric acid and a concentrated solution, cooling and crystallizing the concentrated solution, and performing solid-liquid separation to obtain a chloride solid and an acidic solution.

7. The method according to claim 1, wherein the step S1 includes oil-water mixing, clarification and stratification, and oil-water separation;

the main reaction formula of the extraction is as follows: 2RH + Cu²⁺＝CuR₂+2H⁺RH is an extracting agent;

the dissociation reaction formula of the copper complex ion is: CuL_m＝Cu²⁺+ mL, L is NH₃Or Cl^-。

8. The method according to claim 1, wherein the step of back-extracting in step S3 comprises the step of recycling the alkaline etching solutionContaining H₂SO₄The copper sulfate after electrodeposition is fully contacted with the washed copper-loaded stripping agent, so that copper is transferred into a water phase from the stripping agent, and the unloaded stripping agent recovers the extraction function;

the back extraction has a main reaction formula of CuR₂+2H₂SO₄＝CuSO₄+2RH, RH as stripping agent.

9. The method according to claim 1, wherein oxygen is generated at the anode during the copper sulfate electrolysis and deposition in the step S4, the oxygen carries with it sulfuric acid mist, and the spraying tower sprays alkaline water foam to neutralize the sulfuric acid mist, so that the discharged gas meets the standard; the PH value of water in the spray tower is within 8-13.

Technical Field

The invention relates to the technical field of alkaline etching solution recovery, in particular to a method for recycling an alkaline etching solution.

Background

The PCB industry in China has kept a 10% annual growth rate for nearly 20 years. Etching is a process which consumes a large amount of chemical liquid in the production of PCBs and also is a process which generates the largest amount of waste liquid and waste water, and generally, about 2 to 3 liters of etching liquid is consumed per one square meter of a double-sided board having a normal thickness (18 μm) and 2 to 3 liters of waste etching liquid is generated. The PCB industry in China consumes more than 6 million tons of refined copper per month, the total copper content in the produced copper etching waste liquid is more than 5 million tons per month, and serious pollution is caused to water resources and soil in the society, particularly in the peripheral areas of PCB plants.

Copper is a heavy metal element existing in soil and human and livestock bodies, the content of the copper in the soil is about 0.2ppm generally, excessive copper can generate precipitation/complexation reaction with enzymes in the human and livestock bodies, and enzyme poisoning occurs to lose physiological functions. Copper in nature is transferred into human bodies and livestock bodies through water bodies, plants and the like, so that the balance of trace elements in the human bodies and the livestock bodies is destroyed, heavy metals are abnormally accumulated in the human bodies, and results of pathogenic denaturation, carcinogenicity and the like are generated.

The monitoring index of copper in the industrial wastewater discharge standard of China is 0.5ppm, the drinking water standard is 0.03ppm, and the relevant standard of Europe and America is more strict. Because the waste copper etching solution contains dozens to hundreds grams per liter of copper and a large amount of other organic and inorganic pathogenic and denatured compounds, the State general environmental protection administration positions the waste copper etching solution of the PCB as dangerous liquid waste, prescribes on-site treatment and prohibits out-of-bounds transfer.

Therefore, the related technology of recycling the waste etching solution has appeared on the market, however, the current technology still has the phenomenon of waste solution discharge in each process, and the complete recycling of the whole system cannot be realized. As the etching is carried out, the concentration of copper ions in the etching solution is higher and higher, the etching speed is slower and slower, and the etching progress and quality are seriously influenced if the copper ions are not replaced. Alkaline etching waste liquid contains not only a large amount of copper ions but also other valuable chemicals. The manufacturer will essentially handle itself or commission a qualified merchant to the recovery process.

Therefore, a novel system and a method for recycling alkaline etching solution are needed to realize energy-saving, environment-friendly and efficient recycling.

Disclosure of Invention

The invention discloses a cyclic regeneration method of an alkaline etching solution, which aims to meet the actual needs and overcome the defects of the prior art, and comprises the following steps:

s1, extracting the alkaline etching waste liquid by using a solvent to obtain a copper-loaded oil phase and a first water phase:

s2, carrying out primary water washing on the copper-loaded oil phase to obtain a second oil phase and a second water phase;

s3, adding a back-extracting agent into the second oil phase to obtain a third oil phase and a third water phase;

s4, electrolyzing the third water phase, depositing copper ions in the third water phase, and exhausting oxygen to obtain an electrodeposited liquid and deposited copper;

s5, combining the third oil phase and the second water phase, and performing secondary washing on the combined mixed solution to obtain a fourth water phase and a fourth oil phase;

and S6, performing membrane treatment fine adjustment or adopting a reduced pressure distillation process on the fourth water phase, and adjusting the pH value to form an alkaline solution.

As a further improvement of the embodiment of the present invention, the step S4 further includes combining the post-electrodeposition solution with the second oil, and performing the back-extraction step in S3 again.

As a further improvement of the embodiment of the present invention, after the step S1, the method further includes performing composition adjustment on the first aqueous phase, and accordingly adding ammonia and ammonium chloride to form a regenerated etching solution.

As a further improvement of the embodiment of the invention, the method further comprises the step of adding Cu to the regenerated etching solution²⁺、NH⁴⁺、Cl^-And measuring the plasma and the pH value, and determining the required added ammonia and ammonium chloride according to the measurement result so as to achieve the accurate control of the component adjustment.

As a further improvement of the embodiment of the present invention, the step S5 is followed by further performing the steps in S1-S5 on the fourth oil phase again.

As a further improvement of the embodiment of the present invention, the step S6 of adopting the reduced pressure distillation process specifically includes performing reduced pressure concentration on the fourth aqueous phase to obtain distilled water containing hydrochloric acid and a concentrated solution, cooling and crystallizing the concentrated solution, and performing solid-liquid separation to obtain a chloride solid and an acidic solution.

As a further improvement of the embodiment of the present invention, the step S1 specifically includes oil-water mixing, clarification and stratification, and oil-water separation;

the main reaction formula of the extraction is as follows: 2RH + Cu²⁺＝CuR₂+2H⁺RH is an extracting agent;

the dissociation reaction formula of the copper complex ion is: CuL_m＝Cu²⁺+ mL, L is NH₃Or Cl^-。

As a further improvement of the embodiment of the present invention, the back-extraction step in the step S3 specifically comprises using H-containing solution₂SO₄The copper sulfate after electrodeposition is fully contacted with the washed copper-loaded stripping agent, so that copper is transferred into a water phase from the stripping agent, and the unloaded stripping agent recovers the extraction function;

the back extraction has a main reaction formula of CuR₂+2H₂SO₄＝CuSO₄+2RH, RH as stripping agent.

As a further improvement of an embodiment of the present invention, the volume ratio of the copper-loaded oil phase and the first aqueous phase in S1 is 2: 1.

As a further improvement of the embodiment of the invention, in the step S4, sulfuric acid is added into the post-electrodeposition solution for back extraction, and the volume ratio of the third oil phase to the sulfuric acid is 1: 1.5.

As a further improvement of the embodiment of the present invention, in the step S4, oxygen is generated at the anode during the copper sulfate electrolysis and deposition, the oxygen carries with the sulfuric acid mist, and the spraying tower sprays alkaline water foam to neutralize the sulfuric acid mist, so that the discharged gas meets the standard; the PH value of the water in the spray tower is within 8-13.

The invention has the following beneficial effects:

the alkaline etching solution recycling system adopts a solvent extraction-electrolytic reduction method by controlling the alkaline etching solution recycling technology of the electrolytic etching solution to separate and recover copper from the failed copper etching solution, and simultaneously, the failed copper etching solution is effectively recovered and recycled by replenishing the medicament.

Drawings

FIG. 1 is a flow chart of a method for recycling alkaline etching solution according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an oxygen sulfuric acid mist absorption system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to meet the actual needs and overcome the defects of the prior art, the invention discloses a cyclic regeneration method of an alkaline etching solution, which comprises the following steps as shown in figure 1:

s1, extracting the alkaline etching waste liquid by using a solvent to obtain a copper-loaded oil phase and a first water phase;

s2, carrying out primary water washing on the copper-loaded oil phase to obtain a second oil phase and a second water phase;

s3, adding a back-extracting agent into the second oil phase to obtain a third oil phase and a third water phase;

s4, electrolyzing the third water phase, depositing copper ions in the third water phase, and exhausting oxygen to obtain an electrodeposited liquid and deposited copper;

s5, combining the third oil phase and the second water phase, and performing secondary washing on the combined mixed solution to obtain a fourth water phase and a fourth oil phase;

and S6, performing membrane treatment fine adjustment or adopting a reduced pressure distillation process on the fourth water phase, and adjusting the pH value to form an alkaline solution.

Step S4 is followed by combining the post-electrodeposition solution with the second oil phase and performing the back-extraction step in S3 again.

Step S1 is followed by adjusting the composition of the first aqueous phase to form a regenerated etching solution by adding ammonia and ammonium chloride.

For Cu of regenerated etching solution²⁺、NH⁴⁺、Cl^-Plasma and pH value measurement, and determining the required amount of ammonia and ammonium chloride to achieve accurate control of component adjustment.

Step S5 is followed by subjecting the fourth oil phase to the steps of S1-S5 again.

The vacuum distillation process adopted in step S6 specifically includes vacuum concentrating the fourth aqueous phase to obtain distilled water containing hydrochloric acid and a concentrated solution, cooling and crystallizing the concentrated solution, and performing solid-liquid separation to obtain a chloride solid and an acidic solution.

Step S1 includes oil-water mixing, clarifying and layering, and oil-water separation;

the main reaction formula of the extraction is as follows: 2RH + Cu²⁺＝CuR₂+2H⁺RH is an extracting agent;

the dissociation reaction formula of the copper complex ion is: CuL_m＝Cu²⁺+ mL, L is NH₃Or Cl^-。

The stripping step in step S3 specifically comprises using a catalyst containing H₂SO₄The copper sulfate after electrodeposition is fully contacted with the washed copper-loaded stripping agent, so that copper is transferred into a water phase from the stripping agent, and the unloaded stripping agent recovers the extraction function;

the back extraction has a main reaction formula of CuR₂+2H₂SO₄＝CuSO₄+2RH, RH as stripping agent.

Further, the volume ratio of the copper-loaded oil phase and the first aqueous phase in S1 is 2: 1.

Step S4 adding sulfuric acid into the solution after electrodeposition for back extraction, wherein the volume ratio of the third oil phase to the sulfuric acid is 1: 1.5.

In step S4, oxygen is generated at the anode during the electrolysis and deposition of copper sulfate, the oxygen carries sulfuric acid mist, and as shown in fig. 2, alkaline water foam is sprayed by the spray tower to neutralize the sulfuric acid mist, so that the discharged gas meets the standard; the PH value of the water in the spray tower is within 8-13.

The invention has the following beneficial effects:

the alkaline etching solution recycling system adopts a solvent extraction-electrolytic reduction method by controlling the alkaline etching solution recycling technology of the electrolytic etching solution to separate and recover copper from the failed copper etching solution, and simultaneously, the failed copper etching solution is effectively recovered and recycled by replenishing the medicament.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the inventive concept of the present invention, which falls into the protection scope of the present invention.