阅读说明：本技术 一种三氯化铁含铜蚀刻废液提铜再生方法 (Regeneration method for extracting copper from ferric trichloride copper-containing etching waste liquid ) 是由 邓炳林 樊文星 罗恒 丁雯 华蔓 于 2020-12-03 设计创作，主要内容包括：本发明公开了一种三氯化铁含铜蚀刻废液提铜再生方法,采用铁粉还原-膜电解联合工艺,使用先进的阳极盒,优化阳极液循环方式,提高传质效率,获得了纯度高、易剥离的铜板和再生蚀刻液产品,且大幅降低了三氯化铁含铜蚀刻液提铜再生的成本,本发明工艺简短,成本低,产品价值高,具有良好的环境和经济效益；解决了现有蚀刻废液处理成本高、电解能耗高、回收的铜纯度低且不易处理等缺陷。(The invention discloses a regeneration method for extracting copper from copper-containing etching waste liquid of ferric trichloride, which adopts an iron powder reduction-membrane electrolysis combined process, uses an advanced anode box, optimizes the circulation mode of anolyte, improves the mass transfer efficiency, obtains a copper plate and a regenerated etching liquid product which have high purity and are easy to strip, and greatly reduces the cost for extracting copper from the copper-containing etching liquid of ferric trichloride; the defects that the existing etching waste liquid treatment cost is high, the electrolysis energy consumption is high, the purity of the recovered copper is low, the treatment is difficult and the like are overcome.)

1. A regeneration method for extracting copper from ferric trichloride copper-containing etching waste liquid is characterized by comprising the following steps:

s010, transferring the etching waste liquid into a stirring reduction cylinder, adding iron powder, and adding Fe³⁺Reduction to Fe²⁺；

S011, filtering after the reaction is finished to obtain a high-copper ferrous chloride solution, wherein the solution components of the high-copper ferrous chloride solution are controlled to be Cu²⁺％2－6％，TFe％8－15％，Fe³⁺＜1％；

S012, mixing the high-copper ferrous chloride solution with the low-copper ferrous chloride in the low-copper ferrous chloride tank, and then introducing the mixture into a cathode chamber of an electrolytic tank, wherein a feed inlet and a discharge outlet of the cathode chamber of the electrolytic tank are connected with a feed inlet and a discharge outlet of the low-copper ferrous chloride tank through a pipeline, and a liquid phase circulating system is established; electrolyzing to deposit copper ions on the cathode plate to obtain a copper plate;

s013, connecting a feed inlet and a discharge outlet of the anode chamber of the electrolytic cell with a feed inlet and a discharge outlet of the low-copper ferric trichloride cell through pipelines, and establishing a liquid phase circulating system;

s014, the anolyte in the anode chamber of the electrolytic cell is a mixed solution of low-copper ferrous chloride in a tail gas absorption tower and low-copper ferric trichloride in a low-copper ferric trichloride tank; electrolyzing to obtain a ferric trichloride solution with high ORP;

s015, mixing: and (4) mixing the high-OPR ferric trichloride solution from the electrolysis anode with the high-copper ferric trichloride solution obtained in the step S10 according to a certain proportion, and mixing to obtain a regenerated etching solution suitable for the requirements of etching lines.

2. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 1, wherein the method comprises the following steps: the adding amount of the iron powder in the S010 is determined by Fe in the etching waste liquid³⁺Content, in terms of molar ratio n (Fe)³⁺): n (fe) ═ 2-3: 1 in a ratio of 1.

3. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 2, wherein the method comprises the following steps: the electrolysis reaction condition in S012 is current density 1.5-2.5ASD, temperature 20-50 ℃.

4. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 3, wherein the method comprises the following steps: an ORP detector is arranged on a return pipe of the cathode chamber of the electrolytic cell in S012, and the ORP is controlled by the return pipe: 300mv-500mv, Cu²⁺＜1％。

5. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 4, wherein the method comprises the following steps: an ORP detector is arranged on a return pipe of the anode chamber of the electrolytic cell in S013, and the ORP is controlled by the return pipe: ORP800mv-1100mv, Cu²⁺＜1％，TFe：8％－15％。

6. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 5, wherein the method comprises the following steps: in S015, the volume ratio of the high OPR ferric trichloride solution to the high copper ferric trichloride solution is (3-10): 1, the effluent standard of the regenerated etching solution is as follows: ORP: 500-1000mv, Fe²⁺＜1％，TFe：8％－14％，Cu²⁺＜2％。

7. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to any of claims 1 to 6, wherein: the low-copper ferrous chloride and the low-copper ferric trichloride are Cu²⁺< 1% solution.

8. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to any of claims 1 to 6, wherein: the electrolytic cell anode chamber is provided with an anode box, two sides of the anode box are provided with anion membranes which are separated from the cathode chamber, a plating anode plate is arranged in the anode box, and air is introduced into the bottom of the anode box in a mode of directly facing the anode plate to inject liquid and bubble air so as to enhance the mass transfer speed of the anode liquid on the anode plate.

9. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 8, wherein the method comprises the following steps: an air inlet groove is formed in the bottom of the anode box, a plurality of air exposure ports are formed in the air inlet groove, and an air inlet communicated with the air inlet groove is formed in the side wall of the anode box; the bottom of the anode box is provided with a liquid inlet pipe, the liquid inlet pipe is provided with a plurality of liquid outlets, and the side wall of the anode box is provided with a liquid inlet communicated with the liquid inlet pipe.

10. The method for recovering copper from the copper-containing etching waste liquid of ferric trichloride according to claim 9, wherein the method comprises the following steps: the position of the liquid inlet pipe is higher than that of the air inlet groove.

Technical Field

The invention relates to the technical field of printed circuit board waste liquid recycling, in particular to a copper extraction regeneration method of ferric trichloride copper-containing etching waste liquid.

Background

Ferric trichloride is used as an important chemical reagent and chemical raw material, and is mainly used as a water purifying agent and a sewage treatment flocculating agent of drinking water, a printed circuit board, a stainless steel etching agent and the like.

Printed Circuit Boards (PCBs) are important components in electronic devices. With the full development of the electronic industry, China also becomes the largest production country and use market of PCBs, PCBs also become highly competitive industries, and the requirements of the industries are reduced. FeCl₃The etching solution has strong oxidation corrosion effect on metals such as Fe, Cu and the like, and in addition, the etching solution has lower price and higher etching speed than other etching solutions such as copper chloride etching solution, so FeCl₃The etching solution is still widely used in the etching process of the PCB. However, a large amount of FeCl is generated during the etching process₃Waste etching solution with strong corrosivity and a large amount of Fe³⁺、Cu²⁺The direct discharge of the metal ions can cause resource waste and environmental pollution. In recent years, with the development of PCB and shortage of metal resources in China, FeCl is regenerated₃The use of waste etching solutions and the recovery of copper have become a major problem in the fields of metal resource recovery and environmental protection.

Currently, iron powder replacement regeneration, ferrous sulfide precipitation, solvent extraction, crystal electrolysis and ion membrane electrolysis are commonly used for regenerating FeCl₃Spent etching solution and recycled copper product, but the use of these methods presents a number of problems. For example, the purity of copper recovered by the iron powder displacement regeneration method is not high, and the first reduction and second oxidation processes not only waste expensive iron powder but also increase the consumption of chlorine. The ferrous sulfide precipitation method needs iron powder and sulfur powder to generate ferrous sulfide, but the reaction is violent, and secondary pollution is easy to cause. Although the extraction regeneration method realizes good separation of iron and copper, the process is complex, and the purity of the regeneration liquid is reduced by introducing an extracting agent. The purity of the metal recovered by the electrolytic regeneration method is very high, but most of the recovered copper products are in a state of copper powder, copper sludge or the like and are not easy to handle. Meanwhile, the energy consumption in the electrolytic process is very high, and a large amount of toxic gas chlorine is easily generated nearby the anode. In the ion membrane electrolysis process, FeCl may be generated in the anode compartment₃The etching solution is exhausted, and Cu is removed²⁺The catholyte may then be returned to the anode chamber for oxidative regeneration. Although it is used forThe ionic membrane electrolysis method is environment-friendly, but the high power consumption limits the wide application of the process.

Disclosure of Invention

The invention aims to provide a regeneration method for extracting copper from copper-containing etching waste liquid of ferric trichloride, which adopts an iron powder reduction-membrane electrolysis combined process, uses an advanced anode box, optimizes an anolyte circulation mode, improves mass transfer efficiency, obtains a copper plate and a regenerated etching liquid product which have high purity and are easy to strip, and greatly reduces the cost for extracting copper from the copper-containing etching liquid of ferric trichloride; the defects that the existing etching waste liquid treatment cost is high, the electrolysis energy consumption is high, the purity of the recovered copper is low, the treatment is difficult and the like are overcome.

In order to achieve the purpose, the invention adopts the following technical scheme:

s010, transferring the etching waste liquid into a stirring reduction cylinder, adding iron powder and mechanically stirring, and adding Fe³⁺Reduction to Fe²⁺The ion equation for the major reactions is as follows:

2Fe³⁺+Fe＝3Fe²⁺

wherein the amount of the added iron powder is determined according to the Fe content in the etching waste liquid³⁺Content, in terms of molar ratio n (Fe)³⁺): n (Fe) ═ (2-3):1 in the proportion

Wherein, the high-copper ferrous chloride solution is obtained after the reaction is finished, and the solution components are controlled as follows: cu²⁺％2-6％，TFe％8-15％，Fe³⁺＜1％；

S011, performing plate-and-frame filter pressing on the solution after the reaction in the S010 step to finish solid-liquid separation to obtain a high-copper ferrous chloride solution, and transferring the filtrate to the next step;

s012 is an electrolytic reaction system which comprises an electrolytic cell, an anode chamber, a cathode chamber, an anion membrane, a cathode plate, an anode plate and a rectification power supply system;

the catholyte is a mixed solution of the high-copper ferrous chloride and the low-copper ferrous chloride from the low-copper ferrous chloride tank in the step S011, and the reaction conditions are that the current density is 1.5-2.5ASD and the temperature is 20-50 ℃;

the cathode mainly reacts:

2HCl+2e-＝H₂↑+2Cl-

CuCl₂+2e-＝Cu↓+2Cl-

Fe³⁺+e-＝Fe²⁺

and (4) electrodepositing a copper plate on the negative plate, and directly stripping the copper plate after the negative plate is taken out to obtain the product copper plate.

The anode chamber is an independent optimal anode box, the anion membranes are arranged on two sides of the anode box and are separated from the cathode chamber, the plating anode plate is arranged in the anode box, and the mass transfer rate of the anode liquid on the anode plate is greatly enhanced by adopting a mode of directly jetting the liquid into the anode plate and bubbling air at the bottom of the anode box.

The anolyte is a mixed solution of low-copper ferrous chloride from a tail gas absorption tower and low-copper ferric trichloride from a low-copper ferric trichloride tank. The main reaction of the anode chamber:

FeCl₂-e-+Cl-＝FeCl₃

2Cl^--2e-＝Cl₂↑

s013 is a low-copper ferrous chloride groove, is connected with a feed inlet and a discharge outlet of a cathode chamber of the electrolytic cell through pipelines, a liquid phase circulating system is established, an ORP detector is arranged on a backflow pipeline, and an ORP is controlled through a backflow pipe: 300mv-500mv, Cu²⁺＜1％；

S014 is a low copper ferric trichloride tank, which is connected with the feed inlet and the discharge outlet of the anode chamber of the electrolytic cell by a pipeline, a liquid phase circulating system is established, an ORP detector is also arranged on a backflow pipeline, and the backflow pipeline controls ORP: ORP800mv-1100mv, Cu²⁺＜1％，TFe：8％-15％；

S015 is the tail gas absorption tower, and low copper ferrous chloride solution passes through the tail gas absorption tower earlier, absorbs a small amount of chlorine that the electrolysis trough produced and ferrous chloride is oxidized into ferric chloride simultaneously, and the absorption liquid is being sent to the electrolysis trough positive pole, and the tail gas both can discharge to reach standard and can reduce the electrolysis energy consumption, and the main reaction equation of emergence is as follows:

Cl₂+2FeCl₂＝2FeCl₃

s016 is a mixing tank, the ferric trichloride solution with high ORP from the electrolysis anode is mixed with the original ferric trichloride etching waste liquid after physical filtration according to a certain proportion, and the regenerated etching liquid which is suitable for the requirement of an etching line is mixed and sent to an etching production line.

Wherein, the mixing ratio of the effluent of the anode chamber of the electrolytic cell and the filtered stock solution is as follows: volume ratio (3-10): 1, the standard of the regenerated etching solution is as follows: ORP: 500-1000mv, Fe²⁺＜1％，TFe：8％-14％，Cu²⁺＜2％。

The invention provides a copper extraction regeneration method of ferric trichloride copper-containing etching waste liquid, compared with the prior art, the method has good environmental and economic benefits, and the advantages are as follows:

adding iron powder into the waste etching solution through pretreatment, and adding Fe in the waste etching solution in advance³⁺The content is reduced to a certain degree, and the requirement of reducing Fe electrically in the electrolytic process of the cathode chamber of the electrolytic cell³⁺The content of (2) reduces the whole energy consumption;

by adjusting the current density, copper is deposited on the negative plate to be a fine compact plate-shaped structure, the purity is high, and the copper can be directly sold after being stripped from the negative plate; the recovery process is convenient and fast, and the economic value is higher;

by improving the anode box, Fe is accelerated²⁺The mass transfer rate in the solution reduces the chlorine gas generated by the chlorine evolution reaction of the side reaction, reduces the cell voltage and further reduces the electrolysis energy consumption.

Drawings

FIG. 1 is a flow chart of a regeneration method for extracting copper from a copper-containing etching waste liquid of ferric trichloride;

fig. 2 is a schematic structural diagram of a preferred anode box of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, but the technical solutions do not limit the scope of the present invention.

Referring to the attached figures 1-2, the invention provides a method for extracting copper from a ferric trichloride copper-containing etching waste liquid and regenerating the copper, which comprises the following steps:

s010, transferring the etching waste liquid into a stirring reduction cylinder, adding iron powder and mechanically stirringMixing, wherein the amount of the added iron powder is determined according to the Fe in the etching waste liquid³⁺Content, in terms of molar ratio n (Fe)³⁺): n (fe) ═ 2-3: 1 is added in a proportion of;

s011, filtering after the reaction is finished to obtain a high-copper ferrous chloride solution, wherein the solution components are controlled as follows: cu²⁺％2－6％，TFe％8－15％，Fe³⁺＜1％；

And S012 is an electrolysis reaction system which comprises an electrolytic bath, an anode chamber, a cathode chamber, an anion membrane, a cathode plate, an anode plate and a rectification power supply system. The reaction conditions are that the current density is 1.5-2.5ASD and the temperature is 20-50 ℃;

wherein, the catholyte is the mixed solution of the high-copper ferrous chloride and the low-copper ferrous chloride from the step S011, and the liquid inlet mode of the catholyte is as follows: the high copper ferrous chloride pipeline and the low copper ferrous chloride tank cathode chamber pipeline are converged and then enter the cathode chamber, and the pipeline is provided with a flow meter and an adjusting valve.

The anode chamber is an independent preferred anode box, an anion membrane is arranged on two sides of the anode box and is separated from the cathode chamber, and a plating anode plate is arranged in the anode box. The bottom of the anode box adopts a mode of directly facing the anode plate to inject liquid and bubble air, so that the mass transfer rate of the anolyte on the anode plate is enhanced.

The inlet and outlet of the anode box are shown in fig. 2, which is marked as: a liquid outlet 10, an aeration port 11, a liquid inlet pipe 12, an air inlet groove 13, a liquid inlet 14 and an air inlet 15.

The anolyte is a mixed solution of low-copper ferrous chloride from a tail gas absorption tower and low-copper ferric trichloride from a low-copper ferric trichloride tank. The liquid inlet mode of the anode box is as follows: the pipeline from the absorption tower is converged with a pipeline from the low-copper ferric trichloride tank to the anode chamber and then enters the anode chamber, and a flowmeter and an adjusting valve are arranged on the pipeline.

S013 is a low-copper ferrous chloride groove, is connected with a feed inlet and a discharge outlet of a cathode chamber of the electrolytic cell through pipelines, a liquid phase circulating system is established, an ORP detector is arranged on a backflow pipeline, and an ORP is controlled through a backflow pipe: 300mv-500mv, Cu²⁺＜1％；

S014 is a low copper ferric trichloride tank, and a feed inlet and a discharge outlet of an anode chamber of an electrolytic tankThe ORP detector is also arranged on the return pipeline, and the return pipe controls ORP: ORP800mv-1100mv, Cu²⁺＜1％，TFe：8％－15％；

S015 is a tail gas absorption tower, the low-copper ferrous chloride solution passes through the tail gas absorption tower firstly, a small amount of chlorine generated by the electrolytic cell is absorbed, meanwhile, ferrous chloride is oxidized into ferric chloride, the absorption solution is sent to the anode of the electrolytic cell, and the tail gas can reach the standard and be discharged and the electrolysis energy consumption can be reduced;

s016 is a mixing tank, the ferric trichloride solution with high ORP from the electrolysis anode is mixed with the original ferric trichloride etching waste liquid after physical filtration according to a certain proportion, and a regenerated etching liquid which meets the requirement of an etching line is mixed and sent to an etching production line;

wherein, the mixing ratio of the effluent of the anode chamber of the electrolytic cell and the filtered stock solution is as follows: volume ratio (3-10): 1, the standard of the regenerated etching solution is as follows: ORP: 500-1000mv, Fe²⁺＜1％，TFe：8％－14％，Cu²⁺＜2％。

Example 1

The method is adopted to treat the ferric trichloride copper-containing etching waste liquid generated by a certain PCB enterprise, and the etching waste liquid contains 9.34 percent of acidity (calculated by HCl) and Cu²⁺：6.4％，TFe：7.44％，Fe³⁺: 5.86 percent and the specific gravity of 1.297g/cm³(ii) a According to the method of the invention, the processing steps are as follows:

s010, adding iron powder into the etching waste liquid stock solution according to the Fe content in the etching waste liquid³⁺In a molar ratio n (Fe)³⁺): n (fe) ═ 2-3: adding iron powder at the ratio of 1 to react and stirring.

And S011, performing plate and frame filter pressing, and then enabling the filtrate to enter the next step.

S012, controlling the current density of the electrolysis system to be 1.5ASD for electrolysis at 30 ℃. Copper ions are deposited on the negative plate to form a copper plate, and the copper plate is stripped to obtain an electrolytic copper plate, wherein the mass fraction of the electrolytic copper plate is 99.5%.

S013, a low-copper ferrous chloride groove is connected with a feed inlet and a discharge outlet of a cathode chamber of the electrolytic cell through pipelines, a liquid phase circulating system is established, an ORP detector is arranged on a backflow pipeline, and an ORP is controlled through a backflow pipe:430mv，Cu²⁺＜1％。

s014, connecting a low-copper ferric trichloride tank with a feed inlet and a discharge outlet of an anode chamber of an electrolytic cell by a pipeline, establishing a liquid phase circulating system, and arranging an ORP detector on a return pipeline. The anode chamber is an independent preferred anode box, an anion membrane is arranged on two sides of the anode box and is separated from the cathode chamber, and a plating anode plate is arranged in the anode box. The bottom of the anode box adopts a mode of directly injecting liquid inlet to the anode plate and bubbling air, so that the mass transfer rate of the anolyte on the anode plate is greatly enhanced. The anolyte is a mixed solution of low-copper ferrous chloride and low-copper ferric trichloride from a tail gas absorption tower, and an ORP (oxidation-reduction potential) of an anolyte return pipe is controlled to be 700 mv.

S016, a mixing tank, wherein the ferric trichloride solution with high ORP from the electrolysis anode and the original ferric trichloride etching waste liquid after physical filtration are mixed according to the volume ratio of 8: 1, mixing the raw materials in a ratio of 1, mixing the raw materials to obtain regenerated etching solution which meets the requirements of an etching line, and conveying the regenerated etching solution to an etching production line.

Thus, the copper-containing etching waste liquor of ferric trichloride of example 1 was treated to obtain a 99.5 mass percent electrolytic copper plate product and ORP: 564mv, Fe³⁺：9.52％，Fe²⁺：0.43％，Cu²⁺: 1.56% regenerated ferric chloride etched liquid product.

Wherein, the energy consumption comparison under the treatment of the two methods is as follows:

processing method	Anode	Current Density/ASD	Average voltage/V	Copper/kg	Power consumption/kw.h.t-1
						Direct electrolysis	Common anode box	1.5	3.18	86.2	7070.15
The method of the invention	Preferred anode box	1.5	2.21	80.5	4031.01

Compared with direct electrolysis, the method of the invention reduces the cell voltage from 3.18V to 2.21V and the power consumption per ton of copper from 7070.15kw.h to 4031.01 kw.h.

Example 2

The method is adopted to treat the ferric trichloride copper-containing etching waste liquid generated by a certain PCB enterprise, and the etching waste liquid contains 2.38 percent of acidity (calculated by HCl) and Cu²⁺％6.19％、TFe％13.46％、Fe³⁺% 5.15% gravity 1.564; according to the method of the invention, the processing steps are as follows:

s010, adding iron powder into the etching waste liquid stock solution according to the Fe content in the etching waste liquid³⁺In a molar ratio n (Fe)³⁺): n (fe) ═ 2-3: adding iron powder at the ratio of 1 to react and stirring.

And S011, performing plate and frame filter pressing, and then enabling the filtrate to enter the next step.

S012, controlling the current density of the electrolysis system to be 2.0ASD for electrolysis at the temperature of 40 ℃. Copper ions are deposited on the negative plate to form a copper plate, and the copper plate is stripped to obtain an electrolytic copper plate, wherein the mass fraction of the electrolytic copper plate is 99.6%.

S013, a low-copper ferrous chloride groove is connected with a feed inlet and a discharge outlet of a cathode chamber of the electrolytic cell through pipelines, a liquid phase circulating system is established, an ORP detector is arranged on a backflow pipeline, and an ORP is controlled through a backflow pipe: 350mv, Cu²⁺＜1％。

S014, connecting a low-copper ferric trichloride tank with a feed inlet and a discharge outlet of an anode chamber of an electrolytic cell by a pipeline, establishing a liquid phase circulating system, and arranging an ORP detector on a return pipeline. The anode chamber is an independent preferred anode box, an anion membrane is arranged on two sides of the anode box and is separated from the cathode chamber, and a plating anode plate is arranged in the anode box. The bottom of the anode box adopts a mode of directly injecting liquid inlet to the anode plate and bubbling air, so that the mass transfer rate of the anolyte on the anode plate is greatly enhanced. The anolyte is a mixed solution of low-copper ferrous chloride and low-copper ferric trichloride from a tail gas absorption tower, and an ORP (oxidation-reduction potential) of an anolyte reflux pipe is controlled to be 1000 mv.

S016, a mixing tank, wherein the ferric trichloride solution with high ORP from the electrolysis anode and the original ferric trichloride etching waste liquid after physical filtration are mixed according to the volume ratio of 4: 1, mixing the raw materials in a ratio of 1, mixing the raw materials to obtain regenerated etching solution which meets the requirements of an etching line, and conveying the regenerated etching solution to an etching production line.

Thus, the ferric trichloride copper-containing etching waste liquid obtained in example 2 is treated by the method to obtain a plate-shaped copper product with the mass fraction of 99.6%, and the obtained parameter is Fe³⁺％：13.23％，Fe²⁺％：1.03％，Cu²⁺Percent: 1.32% regenerated ferric chloride etching liquid product

Wherein, the energy consumption comparison under the treatment of the two methods is as follows:

while the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.