KR20050065030A - A reusing method of waste water comprising copper and hydrochloric acid as etching solution and cucl powder - Google Patents

Abstract

The present invention relates to a method for diffusing dialysis of copper and hydrochloric acid containing waste liquids and recycling them into an etching solution and cuprous chloride powder. Filtering the waste liquid containing copper and hydrochloric acid to remove solid sludge; Recovering hydrochloric acid and diffusing dialysis such that the free acid concentration in the remaining copper solution is 20 g / l or less and the copper ion concentration is 50 g / l or more; Recycling the waste solution containing copper and hydrochloric acid into the hydrochloric acid etching solution and cuprous chloride powder, comprising: electrolytically collecting the copper solution from which hydrochloric acid is recovered at a current density of 150 to 450 A / m ² . A method is provided.

Description

A Reusing Method of Waste Water Comprising Copper and Hydrochloric Acid as Etching Solution and CuCl Powder}

The present invention relates to a method of recycling dialysis copper and hydrochloric acid-containing waste liquid into an etching solution and cuprous chloride powder.

More specifically, the present invention is to filter the solid sludge in the hydrochloric acid and copper-containing etching waste solution containing copper and hydrochloric acid generated in the etching process of the copper circuit board, recover the hydrochloric acid by diffusion dialysis and from the remaining copper solution by electrolytic extraction method It relates to a method for recycling hydrochloric acid and copper-containing waste liquor by preparing cuprous chloride powder.

Hydrochloric acid and copper-containing waste liquids generated during etching of copper circuit boards are generally treated by neutralization precipitation or by raising the pH by alkali addition to precipitate copper hydroxide, filtered and heated to produce copper oxide.

However, in the neutralization process, caustic soda, an expensive neutralizing agent, must be used in a large amount and then subjected to several steps of water treatment or copper oxide production. This treatment process is very expensive and there is a problem that the secondary wastewater and a large amount of sludge occurs.

On the other hand, hydrochloric acid and copper-containing etching waste liquids usually contain high concentrations of hydrochloric acid in excess of 200 g / l, and copper or higher temperatures of 100 g / l or more. Therefore, when treated by neutralization precipitation method, a large amount of caustic soda in proportion to the amount of hydrochloric acid is required, and a large amount of expensive copper is discarded as waste.

Therefore, it is required to develop an economical and environmentally friendly technology for recovering and recycling valuable components from hydrochloric acid and copper-containing etching waste liquid generated in the etching process of copper circuit boards.

Accordingly, an object of the present invention is to provide a method for recycling waste liquid containing copper and hydrochloric acid into hydrochloric acid etching solution and cuprous chloride (CuCl) powder.

Another object of the present invention is to filter solid sludge in an etching waste liquid containing copper and hydrochloric acid generated in the etching process of a copper circuit board, recover hydrochloric acid by diffusion dialysis, and cuprous chloride powder by electrolytic extraction from the remaining copper solution. The present invention relates to a method for recycling copper and hydrochloric acid-containing etching waste liquid.

According to the invention,

Filtering the waste liquid containing copper and hydrochloric acid to remove solid sludge;

Recovering hydrochloric acid and diffusing dialysis such that the free acid concentration in the remaining copper solution is 20 g / l or less and the copper ion concentration is 50 g / l or more; And

Electrolytically collecting the copper solution from which hydrochloric acid is recovered at a current density of 150 to 450 A / m ² to obtain cuprous chloride powder;

There is provided a method of recycling copper and hydrochloric acid-containing waste liquid with an etchant hydrochloric acid and cuprous chloride powder.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the present invention, a waste solution containing hydrochloric acid and copper (hereinafter referred to as hydrochloric acid / copper waste liquid) contains a large amount of hydrochloric acid and copper ions, and the hydrochloric acid and copper ions can be separated and recycled as valuable resources. It was conceived in that it exists.

That is, in the present invention, the acid recovered from the hydrochloric acid / copper waste solution by diffusion dialysis is recycled to hydrochloric acid etching solution, and the hydrochloric acid is removed and the copper solution containing a large amount of copper (hereinafter referred to as 'copper solution'). By producing cuprous chloride powder by electrolytic extraction, the hydrochloric acid / copper waste liquid is recycled into hydrochloric acid etching solution and cuprous chloride powder.

Examples of the hydrochloric acid and copper-containing waste liquid include hydrochloric acid and copper-containing etching waste liquid generated in the etching process of the copper circuit board. The composition ranges of the hydrochloric acid and the copper-containing etching waste liquid generated in the etching process of the copper circuit board are shown in Table 1 below.

TABLE 1

As can be seen from Table 1, the composition of hydrochloric acid and copper-containing etching waste liquid generated in the etching process of the copper circuit board has a very high hydrochloric acid concentration of 200 g / l or more and a copper ion concentration of 90 g / l or more. The other components are contained in a small amount.

However, in the case of treating such a high concentration of hydrochloric acid waste solution by neutralization precipitation, which is a conventional method, a large amount of neutralizing agent is added and heavy metal sludge is generated.

Therefore, in the present invention, the solid sludge in the copper and hydrochloric acid-containing etching waste liquid generated in the etching process of the copper circuit board is filtered, hydrochloric acid is recovered by diffusion dialysis, recycled as an etching solution, and cuprous chloride by electrolytic extraction from the remaining copper solution. Powders can be prepared.

The hydrochloric acid / copper waste liquor is first filtered to remove solid sludge components in the waste liquor. The solid sludge component can be filtered using, for example, a micro cartridge filter. The solid sludge component is filtered to remove the dialysis membrane from contamination in the next step of diffusion dialysis.

The filtered hydrochloric acid / copper waste liquid is diffusely dialyzed to recover hydrochloric acid, and the free acid concentration and copper ion concentration in the hydrochloric acid / copper waste liquid are controlled so as to be suitable for obtaining cuprous chloride by electrolytic extraction.

The hydrochloric acid recovered from the diffusion dialysis is recycled to the etching solution. On the other hand, diffusion dialysis is performed by diffusion dialysis in a copper solution remaining after hydrochloric acid recovery so that the free acid is 20 g / l or less and the copper ion concentration is 50 g / l or more. In addition, the electrolytic extraction should be carried out while maintaining the concentration of free acid in the copper solution at 20 g / l or less and the copper ion concentration at 50 g / l or more.

When the concentration of free acid in the electrolyte exceeds 20 g / l in the electrolytic extraction process, which is a subsequent process, it is difficult to work such as requiring a separate gas treatment device due to the high hydrogen generation. It is difficult to collect electrolytic copper powder. The smaller the concentration of free acid remaining in the copper solution after Hanfen and diffusion dialysis, the easier it is to obtain cuprous chloride in the subsequent electrolytic extraction. In addition, as the concentration of free acid remaining in the copper solution decreases, more acid is preferably recovered.

In addition, the copper ion concentration of 50 g / l or more should be secured to enable the production of cuprous chloride powder by electrowinning. Hydrochloric acid is recovered by diffusion dialysis, and the higher the concentration of copper ions in the remaining copper solution is, the better the electrolytic extraction for obtaining cuprous chloride. Therefore, the higher the concentration of copper ions in the copper solution, the higher is 50g / l or more is preferable.

Hydrochloric acid is recovered during diffusion dialysis, and the cuprous chloride powder is prepared by electrolytically collecting the remaining copper solution at a current density of 150 to 450 A / m ² . Other electrochemical harvesting conditions and related electrochemical factors except current density can be properly adjusted under general conditions.

The current density is the most influential factor in obtaining cuprous chloride powder by the electrolytic extraction method. When electrolytic extraction is carried out by applying a current density exceeding 450 A / m ² , CuCl and Cu are mixed and precipitated, and Cu is mixed. CuCl is not recyclable. In the case of electrowinning at a current density of less than 150 A / m ² , a complex of CuCl, Cu, and Cu ₂ (OH) ₃ Cl is precipitated, and thus recycling is impossible. In the case of electrowinning at a current density of 150 to 450 A / m ² , mud-type CuCl powder is precipitated.

CuCl powders are pigments (raw material of phthalocyanine blue), chemicals (catalyst of organic compound reaction), petrochemical (catalyst, bleach, desulfurization agent), cellulose (denitrification agent), pesticide raw material, chlorination catalyst, temperature change measurement, It is used in insecticides, acetylene tablets, CO absorbers, acrylonitrile, brighteners, bleaching agents, soldering solvents, and electric batteries.

By recovering and recycling hydrochloric acid and cuprous chloride powder from hydrochloric acid and copper-containing waste liquid by the method of the present invention, waste resources can be efficiently recycled.

Hereinafter, the present invention will be described through examples.

EXAMPLE

The treatment capacity was 2000 ml / min, and the copper and hydrochloric acid-containing etching waste liquid generated in the etching process of the copper circuit board was filtered by using a pretreatment filtration device composed of an acid resistant cartridge filter and an acid resistant magnet pump.

In order to prevent membrane fouling in the post-diffusion diffusion dialysis process, it was adjusted to SDI 4 or less. SDI (Silt Density Index) was measured using Millipore's SDI Kit.

As a diffusion dialysis apparatus, a diffusion dialysis apparatus equipped with an AFX dialysis membrane of Tokuyama Soda Co. having a treatment capacity of 500 ml / hr was used. In the case of hydrochloric acid and copper-containing etching waste, the acid recovery yield was 85% or more based on the free acid and the metal ion leakage rate was 20% or less.

In the electrode, STS 316 or Cu, which is stainless steel, can be used as the cathode. IrO ₂ coated Ti is used as the anode. Acid pumps, thermostats, rectifiers (constant current, constant voltage) and busbars (Cu) are used. , Electrolyte circulation electrolytic apparatus was used.

Electrodeposits were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS).

Diffusion dialysis test results are shown in Table 2. The concentration of free acid in the copper chloride etching waste liquid from the etching process of the copper circuit board was 116.g / l. The concentration of free acid in copper chloride solution was 1.1 g / l and the recovered hydrochloric acid was released. The concentration of acid was 102.2 g / l.

Diffusion dialysis was performed at room temperature at a flow rate of 0.8-1.0 l / m 2.

By diffusion dialysis, more than 99% of the free acid in the waste liquid was recovered. In addition, diffusion dialysis is preferable because the less the free acid content in the residual solution, the more advantageous it is to electrolytic extraction. Meanwhile, copper ions leaked 26.3 g / l into the recovered hydrochloric acid from the hydrochloric acid and the copper-containing etching waste liquid.

TABLE 2

Diffusion Dialysis Test Results for Copper Chloride Etching Waste

After diffusion dialysis, the copper solution from which the acid was recovered and removed was electrowinned. Electrolyzing was applied to the electrolytic conditions so as to precipitate in the form of CuCl powder when electrodeposited to the anode using a complex bonding state of copper ions and chlorine ions in the copper solution.

Cu plate as cathode and IrO ₂ coated Ti plate as anode, 100A / m ² , 200A / m ² at 20 ~ 25 ℃ and pH 0 ~ 1.0, 1.7V voltage and 200mS / cm conductivity, respectively Electrolytic harvesting was performed at current densities of, 500 A / m ² and 1000 A / m ² . The concentration of copper ions in the copper solution was maintained at 50 g / l or more during the electrowinning.

The electrodeposited materials such as CuCl, Cu, and copper salts deposited on the surface of the cathode according to the change of the reduction current density by electrolytic extraction under the above conditions were investigated. 1A to 4A are XRD analysis graphs of electrodeposits deposited on the cathode according to current density changes, and FIGS. 1B to 4B are surface photographs of electrodeposits deposited on the cathode according to current density changes.

As shown in FIGS. 1A and 2A, a large amount of copper is mixed in a cathode precipitate in a high current density region of 500 A / m ² or more, and a precipitate in FIG. 4A having a current density of 100 A / m ² includes CuCl, Cu, Cu ₂ (OH) 3 Cl In the mixed case, pure CuCl powder was precipitated in the case of FIG. 3A having a current density of 200 A / m ² .

This kind of precipitate can also be seen in the surface photograph. As shown in FIGS. 1B and 2B, in the high current density region of 500 A / m ² or more, the negative electrode precipitates had a high copper content and exhibited a typical copper color as a mixture of metal and powder. As shown in FIG. 3b, when the current density was lowered to 200 A / m ² , dark gray cuprous chloride precipitated in the form of a powder mass. When the current density was lowered to 100 A / m ² as in FIG. 4B, the powder disappeared and precipitated as a gray metal film.

In addition, SEM photographs and EDS analysis graphs of precipitates deposited at current densities of 100 A / m ² and 200 A / m ² are shown in FIGS. 5A, 5B, 6A, and 6B, respectively.

According to the EDS analysis, when electrolytically collected at a current density of 100 A / m ² , 55.1% Cu atoms and 44.9% Cl atoms in the precipitates were present as impurities in the precipitates (see FIG. 5B). FIG. 5A is a SEM photograph (magnification × 1000) of precipitated precipitate at 100 A / m ² in water during the washing process.

In the current collection of 200A / m ² , the presence of Cu was not detected at all by XRD analysis, and the EDS analysis showed that almost all precipitates were CuCl with 49% Cu and 51% Cl (see FIG. 6B). ). 6A is a SEM photograph (magnification × 1000) of CuCl powder (white) precipitated at 200 A / m ² in water during the washing process.

The etching liquid and CuCl powder can be recovered from the waste liquid containing hydrochloric acid and copper and recycled. In addition, not only the treatment cost required for water treatment or recycling of the hydrochloric acid and copper-containing etching waste liquid can be reduced, but the waste resources can be recycled as valuable resources. The sludge landfill problem generated in the conventional water treatment or recycling process of the etching waste solution is not only solved, but it is also advantageous in terms of environment because secondary contamination by the malignant waste liquid containing heavy metals is prevented.

1A and 1B are XRD analysis graphs and surface photographs of electrodeposits deposited on the negative electrode during the electrochemical extraction at a current density of 1000 A / m 2, respectively.

2A and 2B are XRD analysis graphs and surface photographs of electrodeposits deposited on the negative electrode during electrolysis at a current density of 500 A / m 2, respectively.

3A and 3B are XRD analysis graphs and surface photographs of electrodeposits deposited on the cathode during electrolysis at a current density of 200 A / m 2, respectively.

4A and 4B are XRD analysis graphs and surface photographs of electrodeposits deposited on the negative electrode during electrolysis at a current density of 100 A / m 2, respectively.

5A and 5B are SEM photographs and EDS analysis graphs of the electrodeposited precipitates during electrowinning at current densities of 100 A / m 2, respectively.

6A and 6B are SEM photographs and EDS analysis graphs of the electrodeposited precipitates during electrowinning at current densities of 200 A / m 2, respectively.

Claims (3)

Filtering the waste liquid containing copper and hydrochloric acid to remove solid sludge; Recovering hydrochloric acid and diffusing dialysis such that the free acid concentration in the remaining copper chloride solution is 20 g / l or less and the copper ion concentration is 50 g / l or more; And Electrolytically collecting the copper solution from which hydrochloric acid is recovered at a current density of 150 to 450 A / m ² to obtain cuprous chloride powder; A method for recycling copper and hydrochloric acid-containing waste liquid by etching hydrochloric acid and cuprous chloride powder comprising a. The method of claim 1, wherein the concentration of the free acid in the copper solution is 20 g / l or less and the copper ion concentration is 50 g / l or more. The method of claim 1, wherein the copper and hydrochloric acid-containing waste liquid is hydrochloric acid and copper-containing etching waste liquid generated during a copper circuit board manufacturing process.