KR101149984B1 - Method for preparing high purity copper sulfate pentahydrate containing a trace amount of impurity from waste copper etchant - Google Patents

Abstract

The present invention relates to a method for producing high purity and low chlorine copper sulfate pentahydrate through an insoluble intermediate having low impurities obtained from a waste copper etching solution generated in an etching process for forming a PCB pattern.

The present invention includes a foreign material removal step of separating impurities by removing an impurity from a waste copper etching solution using a filter and then passing an anion exchange resin; An intermediate generation step of reacting the purified waste copper etching solution with an alkali chemicals to obtain an intermediate of high purity; A dehydration washing step of dehydrating the intermediate and washing with pure water; A chlorine component reducing step of neutralizing the wastewater generated during dehydration with a waste copper etching solution to recover copper hydroxide and then re-dissolving it in the waste copper etching solution to reduce the chlorine content of the waste copper etching solution; A copper sulfate generation step of reacting the intermediate with a sulfuric acid solution to produce a copper sulfate pentahydrate solution in a supersaturated state; A copper sulfate filtration step of removing impurities by precisely filtration of the copper sulfate pentahydrate solution with a filter; A copper sulfate crystal precipitation step of cooling the filtered copper sulfate pentahydrate solution to precipitate copper sulfate pentahydrate crystals; It is characterized in that it comprises a; a dehydration drying step of removing water by injecting a solution containing copper sulfate pentahydrate crystals into the dehydrator and at the same time by injecting hot air into the dehydrator.

Etching, Waste Solution, Waste Copper Etching Solution, Copper Sulfate, Copper Sulfate Pentahydrate, Intermediates, Heavy Metals, Filtration

Description

Method for preparing high purity copper sulfate pentahydrate containing a trace amount of impurity from waste copper etchant}

The present invention relates to a method for preparing copper sulfate hydrate of high purity and low chlorine from waste copper etching solution. The present invention relates to a method for producing high purity and low chlorine through an insoluble intermediate having low impurities obtained from waste copper etching solution generated in an etching process for forming a PCB pattern. A method for producing copper sulfate pentahydrate.

In general, a printed circuit board (PCB) undergoes a process of etching a copper plate to form a pattern. In such an etching process, a copper copper etching solution such as waste copper etching solution or waste alkali etching solution containing harmful components is used. Is generated.

In order to prevent water pollution, the waste copper etching solution is discharged after removing harmful components by a reaction, extraction, or purification method, and may be regenerated as copper compounds usable in various industrial fields.

The waste copper etching solution is about 10% copper containing copper chloride (CuCl ₂ ), about 8% ghhh hydrochloric acid (HCl), about 71% water (H ₂ O) and dozens to hundreds of ppm It is a copper compound containing heavy metals, and the waste alkaline etching solution contains alpine (Cu (NH ₃ ) ₄ Cl ₂ ) containing about 10% copper, 1 to 2% ammonium chloride (NH ₄ Cl), and 1 to A copper compound containing 2% aqueous ammonia (NH ₄ OH), 70 to 75% water (H ₂ 0) and tens to hundreds of ppm heavy metals.

In the present invention, a method for producing high purity and low chlorine copper sulfate used as a raw material for high quality plating or animal medicine from waste copper etching solution.

As a method for producing copper sulfate from waste copper etching solution, Korean Patent Nos. 796818, 745355, and 620112 have been proposed. The proposed methods separate waste copper chloride etching solution by solvent extraction or evaporative concentration. It is a method of refining pure copper or product, which has high energy cost or secondary pollutants, difficult to operate, unstable quality, low copper recovery rate of raw materials, high cost of using expensive raw materials, In particular, the high chlorine content has a disadvantage in that it can not be used as a high-quality plating raw material or animal drug raw material required in the high value-added industry.

The present invention was created in order to solve the problems associated with the conventional method for producing copper sulfate from the conventional copper copper etching solution as described above, to produce an intermediate with a low content of chlorine and heavy metals from the copper copper etching solution and then obtain a high yield from the intermediate. By providing a high-purity and low-chlorine copper sulphate pentahydrate manufacturing method, the recovery rate can be excellent at a low cost, and completed with the focus of the technical problem.

The present invention for realizing the above technical problem is to remove impurities using a waste copper etching solution using a filter and then to remove the foreign matter by removing the heavy metals through an anion exchange resin; An intermediate generation step of obtaining a high purity intermediate by reacting the waste copper etching solution purified in the step of removing foreign substances and heavy metals with alkali chemicals; A dehydration washing step of dehydrating the intermediate and washing with pure water; A chlorine component reduction step of neutralizing the wastewater generated during dehydration in the dehydration washing step with waste copper etching solution to recover copper hydroxide, and then dissolving the recovered copper hydroxide in the waste copper etching solution to reduce the chlorine content of the waste copper etching solution; ; A copper sulfate generation step of reacting the intermediate that has undergone the dehydration step with a sulfuric acid solution to produce a copper sulfate pentahydrate solution in a supersaturated state at a high temperature; A copper sulfate filtration step of removing impurities by precisely filtration of the copper sulfate pentahydrate solution produced in the copper sulfate generation step with a filter; A copper sulfate crystal precipitation step of precipitating copper sulfate pentahydrate crystals by cooling the copper sulfate pentahydrate solution in a supersaturated state filtered through the copper sulfate filtering step; And a dehydration drying step of removing water by injecting the solution containing the copper sulfate pentahydrate crystals generated in the copper sulfate crystal precipitation step into a dehydrator and simultaneously injecting hot air into the dehydrator.

The present invention is capable of producing intermediates with low chlorine concentration by re-dissolving copper compounds obtained by purifying waste copper etching solution and recycling waste water in waste copper etching solution, and minimizing foreign substances and chlorine in heavy metals contained in waste copper etching solution. By making high and low chlorine intermediates and using them as raw materials for copper sulfate pentahydrate, high purity and low chlorine copper sulfate pentahydrate can be produced at low cost, and copper sulfate pentahydrate is rapidly produced with high yield of more than 95%. It can work.

The present invention is to produce a high purity / low chlorine copper sulfate pentahydrate from waste copper etching solution which is a waste solution generated in the etching process for forming a pattern on a printed circuit board,

Removing foreign substances by using a filter to filter out the waste copper etching solution, and then removing the foreign metals by passing through an anion exchange resin to remove and purify heavy metals; An intermediate generation step of obtaining a high purity intermediate by reacting the waste copper etching solution purified in the step of removing foreign substances and heavy metals with alkali chemicals; A dehydration washing step of dehydrating the intermediate and washing with pure water; A chlorine component reduction step of neutralizing the wastewater generated during dehydration in the dehydration washing step with waste copper etching solution to recover copper hydroxide, and then dissolving the recovered copper hydroxide in the waste copper etching solution to reduce the chlorine content of the waste copper etching solution; ; A copper sulfate generation step of reacting the intermediate that has undergone the dehydration step with a sulfuric acid solution to produce a copper sulfate pentahydrate solution in a supersaturated state at a high temperature; A copper sulfate filtration step of removing impurities by precisely filtration of the copper sulfate pentahydrate solution produced in the copper sulfate generation step with a filter; A copper sulfate crystal precipitation step of precipitating copper sulfate pentahydrate crystals by cooling the copper sulfate pentahydrate solution in a supersaturated state filtered through the copper sulfate filtering step; And a dehydration drying step of removing water by injecting the solution containing the copper sulfate pentahydrate crystals generated in the copper sulfate crystal precipitation step into a dehydrator and simultaneously injecting hot air into the dehydrator.

In the foreign matter removal step, the waste copper etching solution is filtered with a precision filter of 10 μm or less to remove particulate foreign matter, and then passed through a strong base anion exchange resin to separate and remove heavy metals, which are soluble impurities, and flow rate of about 5B / V per hour. It is preferable to pass through the anion exchange resin, and more than 95% of the heavy metal can be removed.

The intermediate generation step is a step of injecting the waste copper etching solution purified in the foreign material removal step into the alkaline chemicals mixed with caustic soda and sodium carbonate and then reacting at high temperature to produce a high purity intermediate, injecting the waste copper etching solution into the alkaline chemicals It is ideal to inject slowly over 60 minutes at 80 ~ 90 ℃ condition, and after the reaction of the waste copper etching solution and alkali chemicals at a high temperature is preferably aged for 30 minutes at 90 ~ 100 ℃. At this time, a high purity intermediate may be produced, and the intermediate solution including the produced intermediate has a structure that is easy to dehydrate and wash.

The scheme is as follows.

Waste Chloride Reaction Formula

3CuCl2 + 2Na2CO3 + 2NaOH + H2O-> CuCO3-Cu (OH) 2 + CuO + 6NaCl + CO2 ↑

Waste Alkaline Solution Scheme

2Cu (NH3) 4Cl2 + 2NaOH + Na2CO3-> 2CuO + 4NaCl + H2O + CO2 ↑ + 8NH3 ↑

The dehydration washing step is a process of dehydrating the intermediate solution produced in the intermediate generation step and washing with pure water.When the waste copper etching solution is completed until the foreign substance removal step, intermediate generation step and dehydration washing step, the chlorine concentration is 99% or more, heavy metal 98 High quality intermediates with more than% removal can be obtained.

The chlorine component reduction step is a step of reusing the dehydrated wastewater generated in the dehydration washing step, in order to recover a large amount of alkali chemicals remaining in the wastewater, the wastewater is neutralized and dehydrated with waste copper etching solution and recovered and recovered with copper hydroxide. Re-dissolving copper in the waste copper etching solution reduces the chlorine content of the waste copper etching solution.

Existing dewatering wastewater treatment method is to inflow dewatering wastewater into the wastewater treatment plant to neutralize it using a large amount of acidic chemicals and discharge it by removing heavy metals. On the contrary, the dewatering wastewater treatment method according to the present invention is very economical and efficient by recovering the expensive alkaline components flowing into the wastewater and also reducing the chlorine concentration of the waste copper etching solution by 30% or more. .

The reaction scheme is as follows.

2Na2CO3 + 2NaOH + 3CuCl2 + H20-> CuCO3-Cu (HO) 2 + Cu (OH) 2 + 6NaCl + CO2

CuCO3 ~ Cu (OH) 2 + Cu (OH) 2 + CuCl2 + 6HCl-> 4CuCl2 + 5H2O + CO2

The copper sulfate generation step is to produce copper sulfate pentahydrate from the intermediate that passed through the dehydration step, the sulfuric acid solution and 1 ratio of diluted sulfuric acid and a mixture of pure sulfuric acid and a concentrated ratio of about 5 to 1 in a reactor including a stirring device Ideally, the intermediate is injected to produce copper sulfate pentahydrate, and the temperature in the reactor is preferably maintained at about 60 to 80 ° C. using the heat of dilution generated when diluting pure water and concentrated sulfuric acid.

The scheme is as follows.

CuCO3? Cu (OH) 2 + 2H2SO4 + 7H2O-> 2CuSO4? 5H2O + CO2

CuO + H2SO4 + 4H2O-> CuSO4? 5H2O

In the reaction, when the intermediate is high in chlorine and heavy metal, it has a turbid blue or green color, whereas the intermediate of high purity / low chlorine according to the present invention has a clear and transparent blue color.

In the copper sulfate filtration step, the solution containing the copper sulfate pentahydrate obtained in the copper sulfate generation step is precisely filtered with a 10 μm filter at a high temperature to remove unreacted substances or impurities remaining in the copper sulfate pentahydrate solution. In order to prevent crystal precipitation, it is preferable to use a filtration device made of FRP (Fibre Reinfored Polymer) having high heat retention and corrosion resistance.

The copper sulfate crystal precipitation step is a step of transferring the copper sulfate pentahydrate solution finely filtered in the copper sulfate filtration step to a crystal reaction tank equipped with a stirring device and a cooling device to precipitate crystals, at a stirring speed of 30 to 60 rpm in 10 to 15 hours. By cooling slowly to 10-20 degreeC, copper sulfate pentahydrate of supersaturation state can be precipitated and it can crystallize.

It is desirable to be able to control the crystal grain size in accordance with the use in the crystallization process, it is possible to adjust the crystal grain state by installing an inverter control device to adjust the stirring speed to 30rpm to 60rpm.

The dehydration drying step is a process of separating the solid solution from the copper sulfate pentahydrate solution crystallized in the copper sulfate crystal precipitation step in a centrifugal dehydrator, removing water, and drying the water, and directly injecting air hot air heated to 60 to 80 ° C. after dehydration. By drying quickly in a few minutes, water is efficiently removed.

Conventional drying method is costly and time-consuming by drying the dehydrated crystals in a separate drying device is uneconomical and low productivity, but the drying method according to the present invention can be quickly dried in a few minutes and very cost-effective It is economical.

Through the following examples and comparative examples will be described in detail the present invention. However, it is obvious that the scope of the present invention is not limited only to these examples.

≪ Example 1 >

In the case of manufacturing copper sulfate pentahydrate by recycling waste copper etching solution, which is a waste solution generated in PCB manufacturing process, the intermediate obtained by purifying waste copper etching solution can be used to obtain high quality copper sulfate pentahydrate with high purity and low chlorine yield. It is very economical because it is high, and heavy metals are dissolved in waste copper etching solution, and when used without refining raw materials, the purity of the final product is lowered and the recovery rate is low.

In the pretreatment process, the soluble heavy metal material was selectively removed using a strong basic anion exchange resin.

First, the waste copper etching solution was filtered with a 10㎛ precision filter to remove foreign substances, and the filtered waste copper etching solution was passed through an ion exchange tower filled with a strong basic anion exchange resin (MP1800) at a flow rate of 5 B / V per hour. The heavy metals were purified by removing more than 95%.

The purified copper copper etching solution was used in the copper sulfate pentahydrate reaction to make an intermediate of high purity and low chlorine content under the following conditions.

Dissolve 100g of sodium carbonate in 1000g of water, filter it with 10㎛ GFC filter paper, put into a 2L reactor with temperature control, mix 20g of caustic soda with 25-50% content, and 500g waste copper etching solution (10.5% copper) at 80 ℃ Insoluble intermediates were prepared over 60 minutes while maintaining to 90 ° C., and aged for 30 minutes while maintaining 90 ° C. to 100 ° C.

The solution containing the insoluble intermediate was filtered with NO.2 filter paper (ADVANTEC) and washed three times with 500 ml of pure water to obtain an intermediate crystal.

Analysis of the filtered crystals showed that the chlorine content is 30ppm, heavy metal content is within 10ppm.

The intermediate obtained in the reaction was used as a raw material of copper sulfate pentahydrate. Details are as follows.

1L of pure water is injected into a 2L reactor, and 250g of sulfuric acid (98%) is added while stirring to prepare a 17% sulfuric acid solution.

300 g of the washed intermediate prepared above was added to the sulfuric acid solution to conduct a copper sulfate pentahydrate reaction. At this time, the reaction temperature was raised to 60 ~ 80 ℃ by the heat of dilution, and due to the increase in solubility, copper sulfate pentahydrate was dissolved in a supersaturated state, the solution containing copper sulfate pentahydrate was clear blue.

The clear blue solution was filtered through No. 2 filter support (ADVANTEC) to remove unreacted material or foreign matter and slowly cooled to 10 ° C. to 20 ° C. over 10 to 15 hours while stirring at a speed of 30 rpm to 60 rpm in a water bath.

As cooling progressed, crystals precipitated due to the difference in solubility, and the reaction solution in which the crystals were precipitated was filtered in a vacuum using No. 2 filter paper. In order to remove residual moisture, the filter was sealed and hot air of 60 ° C. to 80 ° C. was blown to remove residual moisture of the copper sulfate pentahydrate.

Finally, the obtained copper sulfate pentahydrate was light blue in color, and the component was analyzed by TITRATOR (titrator) to confirm that the purity was 99.99% and chlorine was 3 ppm. In addition, the analysis of heavy metal impurities with atomic absorption spectrophotometer showed that most of them were less than 1 ppm or not detected.

Therefore, the present invention can produce a high purity and low chlorine copper sulfate pentahydrate of extremely low heavy metal content at low cost, and can realize a high yield of more than 95%.

Comparative Example 1

In Example 1, a waste copper etching solution was added to a caustic soda solution without purification of the waste copper etching solution to prepare an intermediate. As a result of analyzing the components with a titrator, the intermediate metal concentration of the intermediate obtained was 300 ppm or more, and the final copper sulfate obtained The heavy metal content of the pentahydrate was 30 ppm or more.

<Remarks Example 2>

Purifying the waste copper etching solution in Example 1, adding the waste copper etching solution to 50% caustic soda and reacting the components with a titrator, the chlorine content was more than 10000ppm and the heavy metal was more than 50ppm. The chlorine content of copper sulfate pentahydrate was higher than 500 ppm and the concentration of heavy metal impurities was higher than 5 ppm.

Claims (4)

Removing foreign particles by filtering the waste copper etching solution, which is a waste liquid generated in the etching process, through a filter, and then passing through an anion exchange resin to separate and purify heavy metals, which are soluble impurities, to remove the foreign substances; An intermediate generation step of producing a high purity intermediate by reacting the waste copper etching solution purified in the step of removing foreign substances and heavy metals with an alkali chemical agent mixed with sodium carbonate and caustic soda; A dehydration washing step of washing the intermediate with dehydration and pure water; Neutralizing and dehydrating the wastewater generated during dehydration in the dehydration washing step with waste copper etching solution to recover copper hydroxide, and then reusing the recovered copper hydroxide in waste copper etching solution to reduce the chlorine content of the waste copper etching solution. Steps; A copper sulfate generation step of reacting the intermediate obtained through the dehydration washing step with a sulfuric acid solution mixed with pure water and sulfuric acid to produce a copper sulfate pentahydrate solution in a supersaturated state; A copper sulfate filtration step of microfiltration of the copper sulfate pentahydrate solution produced in the copper sulfate generation step to remove unreacted substances or impurities remaining in the copper sulfate pentahydrate solution; A copper sulfate crystal precipitation step of precipitating copper sulfate pentahydrate crystals by cooling the copper sulfate pentahydrate solution in a supersaturated state filtered through the copper sulfate filtering step; Dehydration drying step of removing the water by adding a solution containing the copper sulfate pentahydrate crystals produced in the copper sulfate crystal precipitation step in the dehydrator, and at the same time by injecting hot air into the dehydrator; The reaction of the waste copper etching solution and the alkali chemicals of the intermediate production step is made at 80 ~ 90 ℃; And further comprising a aging step of reacting the waste copper etching solution and the alkali chemicals in the intermediate production step, and then aged for 10 minutes at 90 to 100 ℃; The copper sulfate pentahydrate solution of the supersaturated state filtered through the copper sulfate filtration step is gradually cooled to 10-20 ° C. over 10 to 15 hours. How to. delete delete delete