Regeneration method of ferric trichloride etching solution

Abstract

The invention discloses a regeneration method of a ferric trichloride etching solution, and relates to the field of etching solutions. When the regenerated ferric trichloride etching solution is prepared, the scrapped etching solution and iron powder are uniformly mixed and then are subjected to solid-liquid separation to prepare filter residue copper sponge and filtrate; treating the filtrate with sodium hydroxide to obtain a ferrous chloride solution; uniformly mixing a ferrous chloride solution with hydrochloric acid, and introducing the oxygen-enriched micro-nano bubbles to prepare the regenerated ferric trichloride etching solution. The ferric trichloride etching solution prepared by the invention has excellent high efficiency and environmental protection property.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of etching solution, in particular to a regeneration method of ferric chloride etching solution. BACKGROUND

[0002] With the rapid development of electronic industry, the demand for ferric chloride etching solution is gradually increasing. The current ferric chloride etching solution will be scrapped when the trivalent iron content decreases to a certain level (such as 6%~8%), which leads to a significant decrease in etching ability. In the etching process, a large amount of failed ferric chloride etching solution is inevitably discharged from the production line. The waste liquid contains not only high concentration of valuable metal copper ions, but also chromium, nickel, zinc and other toxic and harmful heavy metals. If it is directly discharged, it will pose a serious threat to the environment. If the etching waste liquid can be treated and recycled, the research results not only can reduce the treatment cost of etching waste liquid, but also can increase the considerable economic benefits of enterprises.

[0003] Currently, the traditional bubble oxidation process is widely used in the field of ferric chloride preparation at home and abroad, which has problems such as low oxygen mass transfer efficiency, long reaction period, high energy consumption and environmental risk. Some international researches have explored to improve the gas-liquid reaction process by enhancing the dispersion efficiency of oxygen, such as using high-speed stirring, pressurized reaction or introducing new catalysts, but the mass transfer bottleneck has not been fundamentally solved. Micro-nano bubble technology has been applied in the fields of environment and aquaculture due to its large specific surface area, long residence time and high mass transfer efficiency, but it has not been applied in the process of chemical reaction intensification, especially in the preparation of ferric chloride. Therefore, the present application provides a high-efficiency and environmentally-friendly regeneration method of ferric chloride etching solution. SUMMARY

[0004] The purpose of the present application is to provide a regeneration method of ferric chloride etching solution to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions:

[0006] A regeneration method of ferric chloride etching solution, the regenerated ferric chloride etching solution is prepared by mixing ferrous chloride solution and hydrochloric acid and then introducing oxygen-rich micro-nano bubbles.

[0007] As an optimization, the ferrous chloride solution is obtained by treating the filtrate with sodium hydroxide.

[0008] As an optimization, the filtrate is prepared by mixing the scrapped etching solution and iron powder and then separating the solid and liquid.

[0009] As an optimization, the scrapped etching solution comes from a printed circuit board factory in Yunfu City, Guangdong Province.

[0010] A regeneration method of ferric trichloride etching solution, comprising the following preparation steps:

[0011] (1) mixing the scrap etching solution and iron powder uniformly, wherein the mass of the iron powder is 1.1-1.3 times of the mass of copper in the scrap etching solution, hydrochloric acid is added to adjust the pH to 1-3, and the stirring is continued at 45-55 DEG C and 100-200 rpm until the mass of the precipitate is unchanged, then iron powder with a mass of 0.4-0.6 times of the mass of trivalent iron in the scrap etching solution is added, hydrochloric acid is added to adjust the pH to 1-2, and the stirring is continued for 1-3 h before filtration to obtain sponge copper and a filtrate;

[0012] (2) taking the filtrate, adding sodium hydroxide to adjust the pH of the solution to 7-8, stirring at 40-50 DEG C and 1000-1200 r / min for 1-3 h before filtration to obtain a ferrous chloride solution;

[0013] (3) mixing the ferrous chloride solution and a hydrochloric acid solution with a mass fraction of 36%-38% according to a mass ratio of 1:(0.5-1.5), adjusting the pH of the solution to 0.3-0.5, under the conditions of 60 DEG C-100 DEG C and 0.1 MPa-0.3 MPa, introducing oxygen-rich micro-nano bubbles with a particle size of 0.05-0.3 mu m, adding sodium nitrite with a mass of 0.001-0.005 times of the mass of the filtrate ferrous chloride solution, and using a Venturi jet to carry out turbulent reaction for 1-2 h to obtain regenerated ferric trichloride etching solution.

[0014] As an optimization, the reaction equation of the sponge copper in step (1) is:

[0015] Cu 2+ +Fe 0 →Cu 0 ↓+Fe 2+ .

[0016] As an optimization, the reaction equation of the reduced trivalent iron in step (1) is:

[0017] 2Fe 3+ +Fe 0 →3Fe 2+ .

[0018] As an optimization, the reaction equation of the regenerated ferric trichloride etching solution in step (3) is:

[0019] 4FeC2+O2+4HCl→4FeCl3+2H2O.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] In preparing the regenerated ferric chloride etching solution, the waste etching solution and iron powder are mixed and then separated into solid and liquid components to obtain filter residue, sponge copper, and filtrate. The filtrate is treated with sodium hydroxide to obtain ferrous chloride solution. The ferrous chloride solution and hydrochloric acid are mixed and then passed through oxygen-enriched micro-nano bubbles to obtain the regenerated ferric chloride etching solution.

[0022] First, the waste etching solution and iron powder are mixed and then separated into solid and liquid components to obtain filter residue sponge copper and filtrate. The filtrate is then treated with sodium hydroxide to obtain ferrous chloride solution. The resulting filter residue sponge copper product can be resold to copper smelters, effectively recovering copper and reducing environmental pollution. The copper residue in the solution can act as a catalyst to improve the production efficiency of the ferric chloride etching solution. Iron powder is used to replace the ferric chloride solution, increasing the iron content and the concentration of ferric iron, thereby improving the etching effect of the regenerated ferric chloride etching solution. The heavy metal sludge generated during filtration can be further recycled and reused without secondary pollution, achieving complete recovery of the waste etching solution.

[0023] Secondly, a regenerated ferric chloride etching solution is prepared by mixing ferrous chloride solution and hydrochloric acid and then introducing oxygen-enriched micro-nano bubbles. The oxygen-enriched micro-nano bubbles with a particle size of 0.05μm~0.3μm increase the contact area with the liquid. Simultaneously, the slow rising speed of the micro-nano bubbles allows sufficient time for oxygen to dissolve and participate in the reaction, increasing the gas-liquid mass transfer area and efficiency. Combined with a Venturi jet injector to create intense turbulence within the reactor, a dual-path oxygen supply is established, improving oxygen utilization, shortening reaction time, reducing reaction pressure, and increasing the production efficiency of the ferric chloride etching solution. Attached Figure Description

[0024] Figure 1 This is a process diagram of the regeneration of the ferric chloride etching solution described in this invention.

[0025] Figure 2 This is a diagram of the regenerated product of the ferric chloride etching solution described in this invention.

[0026] Figure 3 This is a test image of the regenerated product of the ferric chloride etching solution described in this invention. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] The raw materials used in the following examples and comparative examples are all commercially available:

[0029] The discarded etching solution came from a printed circuit board factory in Yunfu City, Guangdong Province.

[0030] Example 1

[0031] A regeneration method of ferric trichloride etching solution, the regeneration method of ferric trichloride etching solution comprises the following preparation steps:

[0032] (1) mix the scrap etching solution and iron powder, wherein the mass of the iron powder is 1.2 times the mass of copper in the scrap etching solution, add hydrochloric acid to adjust the pH to 2, stir at 50℃ and 150rpm until the mass of the precipitate does not change, add iron powder with a mass of 0.5 times the mass of ferric iron in the scrap etching solution, add hydrochloric acid to adjust the pH to 1.5, continue to stir for 2h, then filter to obtain sponge copper and a filtrate;

[0033] (2) take the filtrate, add sodium hydroxide to adjust the pH of the solution to 7.8, stir at 45℃ and 1100r / min for 2h, then filter to obtain a ferrous chloride solution;

[0034] (3) mix the ferrous chloride solution and a 37% mass fraction hydrochloric acid solution according to a mass ratio of 1:1, adjust the pH of the solution to 0.4, under the conditions of 80℃ and 0.2MPa, introduce oxygen gas with a particle size of 0.15μm, add sodium nitrite with a mass of 0.003 times the mass of the filtrate ferrous chloride solution, and use a Venturi jet to perform turbulent reaction for 1.5h to obtain regenerated ferric trichloride etching solution.

[0035] Comparative Example 1

[0036] A regeneration method of ferric trichloride etching solution, the regeneration method of ferric trichloride etching solution comprises the following preparation steps:

[0037] (1) mix the scrap etching solution and iron powder, wherein the mass of the iron powder is 1.2 times the mass of copper in the scrap etching solution, add hydrochloric acid to adjust the pH to 2, stir at 50℃ and 150rpm until the mass of the precipitate does not change, add iron powder with a mass of 0.5 times the mass of ferric iron in the scrap etching solution, add hydrochloric acid to adjust the pH to 1.5, continue to stir for 2h, then filter to obtain sponge copper and a filtrate;

[0038] (2) take the filtrate, add sodium hydroxide to adjust the pH of the solution to 7.8, stir at 45℃ and 1100r / min for 2h, then filter to obtain a ferrous chloride solution;

[0039] (3) mix the ferrous chloride solution and a 37% mass fraction hydrochloric acid solution according to a mass ratio of 1:1, adjust the pH of the solution to 0.4, under the conditions of 80℃ and 0.2MPa, introduce oxygen gas with a particle size of 0.15μm, add sodium nitrite with a mass of 0.003 times the mass of the filtrate ferrous chloride solution, and use a Venturi jet to perform turbulent reaction for 1.5h to obtain regenerated ferric trichloride etching solution.

[0040] Comparative Example 2

[0041] A regeneration method of ferric trichloride etching solution, the regeneration method of ferric trichloride etching solution comprises the following preparation steps:

[0042] (1) mix the scrap etching solution and iron powder uniformly, wherein the mass of the iron powder is 1.2 times of the mass of copper in the scrap etching solution, hydrochloric acid is added to adjust the pH to 2, and the stirring is continued at 50 DEG C and 150 rpm until the mass of the precipitate is unchanged, then iron powder with a mass of 0.5 times of the mass of ferric iron in the scrap etching solution is added, hydrochloric acid is added to adjust the pH to 1.5, and the stirring is continued for 2 hours, then the filter residue sponge copper and ferrous chloride solution are obtained;

[0043] (2) mix the ferrous chloride solution and a 37% mass fraction hydrochloric acid solution uniformly according to a mass ratio of 1:1, adjust the pH of the solution to 0.4, under the conditions of 80 DEG C and 0.2 MPa, oxygen-rich micro-nano bubbles with a particle size of 0.15 microns are introduced, sodium nitrite with a mass of 0.003 times of the mass of the filter solution ferrous chloride solution is added, and the solution is reacted for 1.5 hours by using a Venturi jet to generate turbulence, then regenerated ferric trichloride etching solution is obtained.

[0044] Test Example 1: Environmental protection

[0045] Test method: the mass fraction of each component of the raw ferric trichloride etching solution obtained in the example and the scrap etching solution used in the example is measured according to the GB / T1621 standard.

[0046] Table 1: Environmental protection test result statistics

[0047] Examples Spent etching solution Comparative Example 1 Comparative Example 2 Fe 2+ mass fraction of the quality 0.02% 10.5% 8.2% 0.02% Mass fraction of zinc 0.01% 0.46% 0.01% 0.21% Mass fraction of chromium 0.005% 0.09% 0.05% 0.07% Mass fraction of lead 0.0009% 0.031% 0.0009% 0.023%

[0048] From Table 1 and Figure 3 It can be seen that the regenerated ferric trichloride etching solution obtained in the example of the application meets the GB / T1621 standard. And the by-products generated by the regeneration method of the ferric trichloride etching solution described in the example of the application can be recycled as resources, and the scrap etching solution is fully utilized.

[0049] Test Example 2: High efficiency

[0050] Test method: the mass fraction of Fe 3+ in the raw ferric trichloride etching solution obtained in the example and Comparative Example 1 is measured according to the GB / T1621 standard.

[0051] Table 2: High efficiency test result statistics

[0052] Fe 3+ mass fraction of Fe Fe 3+ mass fraction of Fe Examples 13.8% Comparative Example 1 5.6% Spent etching solution 4.2% Comparative Example 2 13.8%

[0053] Comparative Example 2 does not use oxygen-rich micro-nano bubbles with a particle size of 0.05 microns to 0.3 microns, and from Table 2, it can be seen that the Fe 3+The mass fraction is lower than that of the embodiment, which shows that the contact area between the gas and the liquid is increased, the residence time of the gas in the water is prolonged, and the gas-liquid mass transfer area and efficiency are improved by the oxygen-rich micro-nano bubbles; the severe turbulence is formed in the reaction kettle by the Venturi jet device, a double oxygen supply is formed, the oxygen utilization rate is improved, and the efficient regeneration of the ferric chloride etching solution is realized.

[0054] The above specific embodiments further explain the purpose, technical solutions and advantages of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for regenerating ferric chloride etching solution, characterized in that, The regenerated ferric chloride etching solution is prepared by mixing ferrous chloride solution and hydrochloric acid and then passing it through oxygen-rich micro-nano bubbles. The ferrous chloride solution was obtained by treating the filtrate with sodium hydroxide. The filtrate is obtained by mixing waste etching solution and iron powder and then separating the solid and liquid components.

2. The method for regenerating ferric chloride etching solution according to claim 1, characterized in that, The preparation steps include the following: (1) Mix the scrap etching solution and iron powder, wherein the mass of the iron powder is 1.1 to 1.3 times the mass of copper in the scrap etching solution. Add hydrochloric acid to adjust the pH, stir at 45 to 55°C and 100 to 200 rpm until the mass of the precipitate remains unchanged, add iron powder of 0.4 to 0.6 times the mass of trivalent iron in the scrap etching solution, add hydrochloric acid to adjust the pH to 1 to 2, continue stirring for 1 to 3 hours and then filter to obtain copper sponge filter residue and filtrate. (2) Add sodium hydroxide to the filtrate to adjust the pH of the solution, stir at 40~50℃ and 1000~1200r / min for 1~3h and then filter to obtain ferrous chloride solution; (3) Mix ferrous chloride solution and hydrochloric acid solution at a mass ratio of 1:(0.5~1.5), adjust the pH of the solution to 0.3~0.5, and introduce oxygen-enriched micro-nano bubbles under the conditions of 60℃~100℃ and 0.1MPa~0.3MPa. Add sodium nitrite at 0.001~0.005 times the mass of the filtrate ferrous chloride solution, and react with turbulent flow using a Venturi jet for 1~2h to obtain regenerated ferric chloride etching solution.

3. The method for regenerating ferric chloride etching solution according to claim 2, characterized in that, The pH value in step (1) is 1 to 3.

4. The method for regenerating ferric chloride etching solution according to claim 2, characterized in that, The pH value in step (2) is 7-8.

5. The method for regenerating ferric chloride etching solution according to claim 2, characterized in that, The hydrochloric acid solution in step (3) has a mass fraction of 36% to 38%.

6. The method for regenerating ferric chloride etching solution according to claim 2, characterized in that, The particle size of the oxygen-rich micro-nano bubbles in step (3) is 0.05μm~0.3μm.

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