KR20040033146A - The recovery equipment and method of copper sulfate from spent soft etching solution for recycling etching solution - Google Patents

Abstract

PURPOSE: A method and an apparatus for recovering molten copper sulfate for recycling waste soft etchant are provided to recycle waste etchant generated in various soft etching processes during fabrication of printing circuit boards by recovering copper sulfate molten in waste etchant and enabling the waste etchant to be reused. CONSTITUTION: The apparatus for recovering molten copper sulfate for recycling waste soft etchant comprises an evaporating and concentrating tank(30) connected to an etching tank(10) for performing soft etching of printing circuit boards to remove moisture and stench of the waste etchant flown in from the etching tank and evaporate and concentrate the waste etchant; first cooling tank(21) for first cooling the waste etchant flown in after being evaporated and concentrated in the evaporating and concentrating tank; second cooling tank(22) for second cooling the waste etchant flown in after being first cooled in the first cooling tank; a cooler(50) connected to the first and second cooling tanks through cooling line(51) to cool the waste etchant of the cooling tanks; a seed injection port(23) formed at one side of an upper part of the second cooling tank; a crystal recovery unit(24) connected to the center of a lower part of the second cooling tank to recover copper sulfate crystal precipitated; a recycling tank(40) connected to the second cooling tank so that the recycling tank injects the prepared etchant into the etching tank again after preparing an etchant by adding sulfuric acid, hydrogen peroxide and water to the waste etchant as much as the copper sulfate recovered after an etchant from which the copper sulfate crystal is recovered is flown into the recycling tank; and a line heater(70) formed on connection line of the etching tank and recycling tank to recover temperature of the cooled etchant again.

Description

The recovery equipment and method of copper sulfate from spent soft etching solution for recycling etching solution}

The present invention relates to a method and apparatus for recovering dissolved copper lactate for recycling of soft etching waste liquid, and more particularly, to recovering dissolved copper dissolved in etching waste liquid in order to recycle etching waste liquid generated in various soft etching processes in PCB manufacturing. The present invention relates to a method and apparatus for recovering dissolved copper lactate for the recycling of soft etching waste liquid.

In general, a printed circuit board (PCB) used in all electronic products is a thin board in which integrated circuits and electrical components such as resistors or switches are introduced. The order in which a normal printed circuit board is made is as follows. After coating a copper film on a thin substrate made of epoxy or bakelite resin as an insulator, a corrosion resistant paint is printed on the desired circuit wiring. When etching is carried out to immerse the printed substrate in a copper-melting corrosive solution, the corrosion-free paint is corroded, and then the corrosion-resistant paint is removed, leaving only the prescribed circuitry in which the copper film is drawn in the desired shape. Will be. When the corrosion operation is repeated several times, the copper concentration in the etching solution is increased, and when the copper concentration is 50 g / l or more, the etching function is degraded and the quality of the product is degraded, thereby treating the etching solution. However, the etching waste solution to be disposed of waste water is generated, causing serious environmental pollution, the production cost is increased, such a situation that there is an urgent need for a recycling method of the etching waste liquid.

Recycling methods conventionally used include a method of regenerating copper and lactic acid copper using aluminum (Al), such as Chinese patent 1087389 filed by Yang et al. In 1992, and PCT / JP 95, filed by Shuji Hosoda and 3 others in 1995. / 01673 (Registration No .: Patent-0264446) to recover the etching waste liquid using alkaline cupric chloride etchant to extract the extraction solvent, the method of cooling the etching waste liquid with air to precipitate the copper lactate, etc. As a method currently performed by domestic and foreign companies, the copper sulfate (CuSO ₄ ) concentration of the etching solution is measured during etching, and when the copper concentration is increased, sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ) are added to the etching solution. Soft etching is performed by adjusting the concentration, and the amount of etching waste liquid that has been replenished is requested by a waste company for processing. There are many problems such as environmental pollution caused by the waste.

The present invention is created to solve the above conventional problems,

The purpose of the method is to recover the dissolved lactate copper for recycling the soft etching waste liquid to recover the dissolved copper dissolved in the etching waste liquid in order to recycle the etching waste liquid generated in various soft etching processes during PCB manufacturing and to reuse the etching waste liquid. To provide a device.

The present invention provides an etching tank for soft etching a printed circuit board, an evaporation concentration tank for removing moisture and odors of an etching waste liquid, and an evaporation concentration liquid for evaporating and concentrating the etching waste liquid, and an etching introduced after evaporation and concentration in the evaporation concentration tank. A primary cooling tank for primary cooling of the waste liquid, a secondary cooling tank for secondary cooling of the etching waste liquid introduced after the first cooling in the primary cooling tank, and a seed inlet formed at an upper side of the secondary cooling tank And a crystal recovery device connected to the lower center of the secondary cooling tank to recover the precipitated lactate copper crystals, and connected to the secondary cooling tank to recover the lactate copper crystals and inject the remaining etching waste solution into sulfuric acid, hydrogen peroxide, and water. Re-produce a certain concentration of the etching solution by adding a recycling tank for storing the etching solution that can be reused, formed on the connection line of the etching tank and the recycling tank and cooled And dissolved copper sulfate recovery system for the recycling of soft etching waste liquid, characterized in that the line consists of a heater to recover to the temperature of the etching solution,

Moving the etching waste liquid subjected to various soft etching processes from the etching tank to the evaporation concentration tank, removing the moisture and odor of the etching waste liquid introduced into the evaporation concentration tank, and then moving the etching waste liquid to the primary cooling tank; The step of cooling the etching waste flowed into the cooling tank to the secondary cooling tank by first cooling the cooling device, and adding a seed of lactic acid copper (etched) to the etching waste flowed into the secondary cooling tank (secondary cooling) Recovering the lactic acid copper crystals precipitated in the secondary cooling tank with a crystal recovery device, moving the etching copper liquid from which the lactic acid copper crystals have been recovered to a recycling tank, and depositing the copper copper crystals in the moved etching liquid Reducing sulfuric acid, hydrogen peroxide, and water to a predetermined concentration by reducing the amount of sulfuric acid, and returning the etching liquid reduced to a predetermined concentration to the etching tank. The object pursued by the present invention can be achieved by providing a method for recovering dissolved copper lactate for recycling of the soft etching waste liquid, characterized in that the step of recycling.

1 is an apparatus configuration diagram for recycling of the soft etching waste liquid of the present invention,

2 is a block diagram of an evaporation concentrator of the present invention;

3 is a key plan diagram related to the recycling method of the etching waste liquid of the present invention;

4 is a copper concentration change during precipitation of lactic copper in an embodiment of the present invention,

5 is a lactic acid copper crystal picture of an embodiment of the present invention,

6 is a lactic acid copper crystal picture of the embodiment of the present invention,

Figure 7 is a change in copper concentration of the solution after the evaporation concentration time and crystallized copper lactate crystal of the present invention.

<Description of the symbols for the main parts of the drawings>

(10): etching tank (20): cooling tank

(21): primary cooling tank (22): secondary cooling tank

(23): seed inlet (24): crystal recovery device

(30): evaporative concentration tank (31): circulation pump

(32): bubble generator 33: heater

(34): thermometer (35): water level sensor

(36): blower (37): capture tank

38: propeller 40: recycling tank

(50) Cooling device (51): Cooling line

60, 61, 62: Pump 70 Line Heater

The construction and the operation of the embodiment of the present invention to accomplish the object as described above and to solve the problems in the prior art will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an apparatus for recycling the soft etching waste solution of the present invention, FIG. 2 is a block diagram of an evaporation concentrating device of the present invention, and FIG. 3 is a key plan diagram of a recycling method of the etching waste solution of the present invention. As illustrated, an etching tank 10 for soft etching a printed circuit board and an etching waste liquid introduced by the pump 60 connected to the etching tank 10 to remove moisture and odor contained in the etching waste liquid. The evaporation concentrator 30, the primary cooling tank 21 for cooling the etching waste liquid moved after being concentrated in the evaporation concentrator 30 to 15 ~ 20 ℃, and the primary cooling tank 21 2) a secondary cooling tank 22 for recooling the etching waste liquid cooled at 0) to 0-4 ° C to precipitate lactic acid copper crystals, a seed inlet 23 formed at an upper side of the secondary cooling tank, and the secondary cooling. The crystal recovery device 24 connected to the lower end of the tank, and the secondary cooling tank 22 After the crystals have been recovered, the remaining etching waste liquid is introduced by the pump 61 to add a sulfuric acid and hydrogen peroxide to the amount of the recovered copper lactate to maintain a predetermined etching solution concentration, and the recycling tank 40 A pump 62 for reflowing the etchant into the etching tank 10, a line heater 70 formed at a connection line between the etching tank 10 and the recycling tank 40 to restore the temperature of the etchant again; , A cooling device 50 for cooling the etchant through the cooling line 51 formed in the cooling tank 20.

The evaporative concentration tank 30, the primary cooling tank 21, the secondary cooling tank 22 is configured in a batch type.

The evaporation concentration tank 30 has an etching tank 10 and a collecting tank 37 connected to the upper portion, a primary cooling tank 21 is connected to the lower portion, and a heater 33 for heating the etching waste liquid therein. ) And an air bubble generator (32), and a circulation pump (31) for crushing the etching waste liquid in the form of a mist using a propeller (38) above the surface of the etching waste liquid, and measuring the level of the etching waste liquid therein. Is attached to the water level control sensor 35 for controlling the operation of the pump 60, and comprises a blower 36 for sending the moisture and odor evaporated from the evaporation tank to the collection tank 37.

The apparatus as described above moves the etching waste liquid subjected to various soft etching processes from the etching tank 10 to the evaporation concentration tank 30, and removes the moisture and odor of the etching waste liquid introduced into the evaporation concentration tank 30. Moving the primary cooling tank 21 to the primary cooling tank 21, and the secondary cooling tank 22 by primary cooling the etching waste liquid introduced into the primary cooling tank 21 to 20 to 25 ° C. using the cooling device 50. The step of moving to, and the step of putting the lactic acid copper seed (seed) in the etching waste liquid introduced into the secondary cooling tank 22, and secondary cooling and left at 0 ~ 4 ℃, and the secondary cooling tank 22 Recovering the lactic acid copper crystals deposited in the crystal recovery apparatus 24, moving the etching copper liquid from which the lactic acid copper crystals have been recovered to the recycling tank 40, and reducing the precipitated copper crystals in the transferred etching liquid. Add sulfuric acid, hydrogen peroxide, and water as needed to return to a predetermined etching solution concentration. Step and operates as a step in recycling send a reduced etching solution to a predetermined concentration back to the etching tank 10 to.

The step of removing the moisture and odor of the etching waste liquid in the evaporation concentration tank 30 is the step of heating the etching waste liquid introduced into the evaporation concentration tank 30 to 50 ~ 80 ℃ with the heater 33, the heated etching Generating bubbles with the air bubble generator 32 in the waste liquid, pulverizing the generated etching waste liquid bubbles with the circulation pump 31 and the propeller 38, and evaporating the particles; Sucks into the blower 36 to be collected in the collecting tank 37.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

<Example 1>

In manufacturing a printed circuit board (PCB), in the soft etching process, the etching waste liquid in which lactate copper is dissolved is cooled to 20 to 25 ° C. in the primary cooling tank 21, and then moved to the secondary cooling tank 22 to obtain the temperature of the etching waste liquid. It is left to cool to 0 ~ 4 ℃. The copper concentration of the etching waste solution is measured by time while observing the precipitation of crystals on the bottom of the secondary cooling tank 22. The results are shown in <Table 1>.

As can be seen from Table 1, there was no crystal precipitation until 6 hours passed, but it can be seen that crystal growth starts after 12 hours and the crystal growth rate is increased. It can be seen that the copper concentration and crystallization rate of the etching waste liquid have almost no change in concentration after 24 hours, which indicates that the supersaturated copper precipitates and remains in equilibrium as the etching waste liquid is cooled. Able to know.

<Table 1> Copper concentration according to the standing time

Idle time (hrs) One 3 6 12 18 24 36 Copper concentration (g / ℓ) 55 55 52 46 40 38 37

<Example 2>

As in <Example 1>, injecting a copper sulfate crystal powder as a crystallization seed (seed) in the secondary cooling tank 22, and the etching waste liquid to 0 ~ 4 ℃ in the same manner as in <Example 1> Cool. The results are shown in <Table 2>.

As can be seen in Table 2 below, the crystals grow quickly after a period of time after the crystals are grown in a short time compared to the crystal growth state without the addition of a lactic acid copper crystal seed, and thus the copper concentration of the etching solution. It can be seen that is rapidly decreasing. The copper concentration in the etching waste solution was almost unchanged after 12 hours. Compared with the crystal growth without seeding, the etching waste solution containing pre-acid copper crystals had a copper concentration of 55 g / l after 6 hours. It can be seen that the amount is reduced to 40 g / ℓ precipitated many copper lactate crystals.

<Table 2> Copper Concentrations (Incorporation of Crystallized Seeds)

Idle time (hrs) 0 One 3 6 12 18 24 36 Copper concentration (g / ℓ) 55 50 48 40 38 35 34 34

FIG. 4 shows the change in copper concentration during lactic acid precipitation of the present invention by arranging the results of <Example 1> and <Example 2>, and adding a lactic acid copper seed to facilitate precipitation of the lactic acid copper crystals. It shows the copper concentration change of the etching waste liquid when (○) and when it is not added (●). As can be seen in Figure 4, when the seed (seed) is added, the crystal growth proceeds rapidly from the beginning of the standing time, the copper concentration of the etching waste is sharply reduced, and after 12 hours the copper concentration does not change, the equilibrium state It can be seen that it is maintained. On the other hand, when the copper lactate seed (seed) is not added, it can be seen that the copper concentration becomes constant only after 36 hours, and as shown in FIG. 4, the addition of the lactate copper seed (seed) greatly contributes to the crystal growth of the lactate copper. Able to know.

<Example 3>

After cooling the etching waste to 0 ~ 4 ℃ while changing the seed amount into the etching waste in the secondary cooling tank, the size of precipitated lactate copper crystals was observed according to the standing time. The results are shown in <Table 3>.

As shown in FIG. 5, the seed size is in the range of 1 to 2 g / l, and the size of the crystal rapidly grows as the time to leave increases, and after 24 hours, the crystal grows into a large crystal close to 15 mm or more in diameter. It can be seen that it has grown. However, as shown in FIG. 6, in the range of 5-10 g / l of seed injected, small crystals were produced in the range of 2 to 3 mm in diameter, and the number of seeds was passed over time. As it increased rapidly.

<Table 3> The amount of crystallized copper is added according to the amount and time left

Size of Lactic Acid Copper Crystal Diameter

(Unit: mm)

Amount of Lactic Acid Copper Crystals per 1 L of Etching Solution 3 6 18 24 0g 0 One 2 6 1 g 1.5 5 10 17 2 g 2 5 10 15 5 g One One 1 to 2 2-3 10 g One One 1 to 2 2-3

<Example 4>

In order to shorten the supersaturation time of the dissolved lactic acid copper by effectively removing the moisture of the preliminary waste liquid and to promote the precipitation of the crystal, an evaporation concentrator 30 as shown in FIG. 2 was introduced and the etching waste liquid was evaporated and concentrated.

The etching waste liquid was bubbled by the air bubble generator 32 while being heated by the heater 33 and supersaturated lactic acid copper concentration of the etching waste liquid was removed by forcibly evaporating water through the blower 36.

7 shows the change in copper concentration according to the evaporation concentration of the etching waste liquid and the change in copper concentration of the solution after the precipitated copper crystals. The copper concentration of the initial etching waste solution was 38.9 g / l, which is very low compared to 55 g / l, which is the initial copper concentration of <Examples 1 and 2>. After this, the supersaturation was maintained at 55.6 g / l. In addition, when comparing the copper concentration after the precipitated copper crystals, in FIG. 7, after 18 hours, 28.6 g / L was shown, indicating that a large amount of copper was precipitated compared to 35 to 40 g / L of <Examples 1 and 2>. Can be. It is thought that the supersaturated state of lactic acid copper is maintained by removing a large amount of water by using an evaporation concentrator, so that many crystals are precipitated and the water removal method of the evaporation concentrator is very effective.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Of course, such changes will fall within the scope of the claims.

As described above, the present invention is a method for recovering the dissolved lactate copper in the soft etching process during the PCB manufacturing, by cooling the temperature of the etching waste liquid to inject the copper lactate crystals as seeds (seed) to promote crystal precipitation and crystal growth according to the difference in solubility By dissolving the dissolved lactate copper in the sedimentation tank effectively and recovering the precipitated lactose copper, and reuse the remaining etchant, the remaining etching liquid is added again to the predetermined etching solution to maintain the predetermined concentration of the etching solution and sent back to the etching tank to reuse It is possible to greatly reduce the amount of etching waste generated than the treatment method, which is economical due to the reduction of the treatment cost of the etching waste liquid, and can greatly contribute to the prevention of environmental pollution due to the etching waste liquid, which is a very useful invention in terms of environment friendliness.

Claims (6)

An evaporation concentration tank 30 connected to an etching tank 10 for soft etching a printed circuit board to remove moisture and odor of the etching waste liquid introduced from the etching tank and to evaporate and concentrate the etching waste liquid; A primary cooling tank 21 in which the etching waste liquid introduced after the evaporation and concentration in the evaporation concentration tank 30 is first cooled, A secondary cooling tank 22 in which the etching waste liquid introduced after the first cooling in the primary cooling tank 21 is secondly cooled; A cooling device 50 connected to the primary and secondary cooling tanks through a cooling line 51 to cool the etching waste liquid of the cooling tank; A seed inlet 23 formed at an upper side of the secondary cooling tank 22; A crystal recovery device 24 connected to the lower center of the secondary cooling tank 22 to recover the precipitated lactose crystals; The etching waste liquid, which is connected to the secondary cooling tank 22 and flows in the crystallized copper lactate, is introduced into the etching waste liquid by adding sulfuric acid, hydrogen peroxide, and water to the etching waste liquid by the amount of the recovered copper lactate. A recycling tank 40 to be introduced, Dissolved lactic acid copper recovery device, characterized in that consisting of a line heater 70 is formed in the connection line of the etching tank 10 and the recycling tank 40 to recover the temperature of the cooled etching liquid again. The method of claim 1, The evaporation concentration tank 30 is an etching tank 10 is connected to the upper portion, the primary cooling tank 21 is connected to the lower, the circulation pump for crushing the bubble by operating the propeller 38 provided therein With 31, An air bubble generator 32 provided below the inner one side of the evaporation concentration tank to generate bubbles, and a heater 33 to heat the etching waste liquid; A thermometer 34 formed at one side of the evaporation concentration tank to control the heater 33 by measuring the temperature of the etching waste liquid; A water level control sensor 35 attached to one side of the evaporation concentration tank to control the pump 60 to adjust the level of the etching waste liquid; A blower 36 for extracting moisture and odor particles generated in the evaporation concentration tank; Dissolved lactic acid copper recovery device, characterized in that consisting of a collecting tank (37) for collecting the moisture and bad smell sucked by the blower (36). Moving the etching waste liquid subjected to various soft etching processes from the etching tank 10 to the evaporation concentration tank 30; Removing the moisture and odor of the etching waste liquid introduced into the evaporation concentration tank 30 and moving to the primary cooling tank 21; First cooling the etching waste liquid introduced into the primary cooling tank 21 by the cooling device 50 to move to the secondary cooling tank 22; Adding a seed of lactic acid copper to the etching waste liquid introduced into the secondary cooling tank 22, and performing secondary cooling and leaving, and Recovering the crystallized copper crystal deposited in the secondary cooling tank 22 to a crystal recovery device 24; Moving the etching waste liquid from which the copper sulfate crystals have been recovered to a recycling tank 40; Reducing the amount of sulfuric acid, hydrogen peroxide, and water reduced by the precipitation of the copper lactate crystal to the predetermined etching solution concentration to the transferred etching waste liquid; Dissolving the copper lactate copper recovery method comprising the step of recycling the etching solution reduced to a predetermined concentration back to the etching tank (10). The method of claim 3, wherein The primary cooling is cooled to 20 ~ 25 ℃, secondary cooling is cooled to lactic acid copper recovery method characterized in that the cooling to 0 ~ 4 ℃. The method of claim 3, wherein Dissolved lactic acid copper recovery method characterized in that to stand for 16-18 hours after seeding the lactic acid copper in the secondary cooling tank. The method of claim 3, wherein The step of removing the moisture and odor of the etching waste liquid in the evaporation concentration tank 30 is the step of heating the etching waste liquid introduced into the evaporation concentration tank 30 to the heater 33 to 50 ~ 80 ℃, Generating bubbles with an air bubble generator (32) in the heated etching waste liquid; Pulverizing the generated etching waste liquid bubble into a circulation pump 31 and a propeller 38 to evaporate, The evaporation and concentration method of the etching waste liquid, characterized in that the step of collecting the evaporated moisture and odor particles in the blower (36) collecting tank (37).