JP3013552B2 - Regeneration method of ferric chloride etching waste liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating ferric chloride etching waste liquid generated in a step of etching a lead frame used as an electronic component.

[0002]

2. Description of the Related Art As a method of manufacturing a lead frame used as an electronic component, a punching method by stamping or a processing method by etching is employed. In the etching method, usually, a ferric chloride solution is used to dissolve an alloy material such as iron, nickel, or copper, and pattern processing is performed. With a narrower pitch width, finer and more accurate processing is required. Since this etching solution is used repeatedly, the management of the etching solution is one of the important factors to keep the processing accuracy constant.

[0003] The control items of the etching ability include the specific gravity of the solution, the oxidation-reduction potential, and the like. Therefore, the solution is managed by diluting the solution or oxidizing Fe ²⁺ with chlorine gas. However, even if the etching solution is managed by such a method, the heavy metal used for the lead frame material dissolves into the solution, and eventually the etching process cannot be performed. Such a solution
At present, it is neutralized with alkali and disposed of as hydroxide sludge, but it generates new pollution as waste. Therefore, it is desired to recycle and recycle the etching solution by separating only heavy metals other than iron in the etching solution.

As a method for regenerating the waste ferric chloride etching solution, for example, 13.9% by weight of iron and 17.2 g of nickel are used.
l, to a strongly acidic etching waste liquid containing chromium, copper, etc., add a lump of metallic iron of about 2 cm square having projections with a large surface area, heat to a temperature of 50 to 80 ° C., and stir for 1 hour or more to remove nickel. Except for this, there is a method of blowing chlorine gas into the post-treatment liquid (Japanese Patent Publication No. 61-44814). However, this method requires a large amount of metallic iron in order to remove nickel and the like other than iron in the etching waste liquid, and requires a reaction time of one hour or more to increase the removal rate of nickel and the like. There was a problem of becoming.

[0005]

SUMMARY OF THE INVENTION The present invention provides a simple and inexpensive regeneration of an etching solution by removing nickel ions contained in a ferric chloride etching waste solution using a small amount of iron source in a short time. It is the purpose.

[0006]

According to the present invention, porous iron powder is added to a ferric chloride etching waste liquid containing nickel ions at a temperature of 50 ° C. or more, and nickel is added to the nickel weight in the ferric chloride etching waste liquid. After reducing and depositing the nickel ions by adding 1.5 times or more, the solids in the ferric chloride etching waste liquid are separated, and then the oxidation and concentration of the ferric chloride etching waste liquid are performed. Features.

[0007] As porous iron powder, mill scale or high-purity iron ore produced during hot rolling of steel is used as a raw material, reduced with coke and pulverized sponge iron.
There are mill-scale reduced iron powder, ore-reduced iron powder, etc. obtained by finishing reduction in decomposed ammonia gas.

[0008]

According to the method of the present invention, nickel ions contained in the ferric chloride etching waste liquid are subjected to an oxidation-reduction reaction using a porous iron powder, whereby the nickel ions are easily deposited as metal on the iron powder. I have found it.

The reason why the etching waste liquid is heated to 50 ° C. or more before adding the iron powder to the etching waste liquid is that the temperature is 50 ° C.
If the temperature is lower than 0 ° C., the oxidation-reduction reaction is slow, and as a result, the nickel ion removal rate decreases as shown in FIG.

Further, the iron powder added to the etching waste liquid needs to be porous, as shown in FIG. 2, because the amount of iron powder required to precipitate nickel ions is smaller than that of non-porous electrolytic iron powder. This is because the amount is small and the precipitation of nickel ions is completed in a short time as shown in FIG. The amount of porous iron powder required to reduce nickel ions and precipitate them as metal is at least 1.5 times, preferably at least 2.5 times, the amount of nickel contained in the etching waste liquid. When copper ions and the like are contained in the etching waste liquid, the copper ions and the like can be removed by increasing and adding the amount of iron powder necessary for reductively depositing the copper ions and the like.

[0011]

【Example】

Example 1 Iron 10% by weight, nickel 77 g / l, specific gravity 1.48,
100 ml of ferric chloride etching waste liquid having an oxidation-reduction potential (hereinafter referred to as ORP) of 629 mV was collected in a 500 ml tall beaker, and heated to temperatures of 20 ° C and 50 ° C. While stirring the heated etching waste liquid at 200 rpm, ²⁰ g of porous iron ore reduced iron powder (manufactured by Hennegas) having a specific surface area of 0.17 m ² / g was added. After adding iron powder
Every 5, 10, 20, 30, and 40 minutes, an analysis sample was collected from the etching waste liquid by micropepit so that no solid matter was mixed therein, diluted 1000 times, and then inductively coupled plasma emission spectroscopy ( ICP) was used to measure the concentration of nickel ions.

The relationship between the elapsed time and the nickel ion removal rate was determined, and the results are shown in FIG. From FIG. 1, it can be seen that the temperature before the addition of iron powder of the etching waste liquid is 50 ° C. or more, and the nickel ion removal rate is good.

To the waste etching solution at a temperature of 50 ° C., 20 g of porous iron powder was added, reacted for 40 minutes, and immediately filtered. Chlorine gas was flowed into the filtrate at a rate of 1 l / min for 5 minutes to regenerate the etching solution. The regenerated etching solution contained 14.5% by weight of iron, 0.3g / L of nickel,
Specific gravity was 1.47 and ORP was 734 mV. This etching solution was concentrated until the specific gravity became 1.52, and a lead frame material (Fe 58% by weight, N 2
i 42% by weight), the etching rate was the same as that of the new solution.

Example 2 100 ml of an etching waste liquid having the same composition as in Example 1 was added to 5
After heating to 0 ° C., the same porous iron powder as in Example 1 was mixed with Fe /
10, 12, 14, 16, and 20 g were added so that the Ni ratio was 1.3, 1.6, 1.8, 2.1, and 2.6. The nickel ion concentration in the etching waste liquid 40 minutes after the addition of the iron powder was measured by the same method as in Example 1, and the relationship between the amount of the added iron powder and the nickel ion removal rate was determined, and is shown in FIG.

Comparative Example In Example 2, the porous iron powder was prepared by adding 0.15 m ² /
g of electrolytic iron powder (manufactured by Toho Zinc Co., Ltd.) so that the Fe / Ni ratio becomes 1.3, 2.6, 3.9, 5.2, and 6.5.
The same procedure was carried out except that 0, 20, 30, 40 and 50 g were added, and the results are shown in FIG. FIG. 2 shows that the porous iron powder can remove nickel ions in a smaller amount than the electrolytic iron powder having an Fe / Ni ratio of 1.5 or more.

EXAMPLE 3 100 ml of an etching waste liquid having the same composition as in Example 1 was added to 5
After heating to 0 ° C., 20 g of the same porous iron powder as in Example 1,
20 g and 30 g of the same electrolytic iron powder as in the comparative example were added.
After the addition of the iron powder, the nickel ion concentration in the etching waste liquid was measured at the same elapsed time as in Example 1 by the same method as in Example 1, and the relationship between the elapsed time and the nickel ion removal rate was determined. The result is shown in FIG. FIG. 3 shows that the porous iron powder can remove nickel ions faster than the electrolytic iron powder.

[0017]

According to the present invention, nickel ions in a ferric chloride etching waste liquid can be efficiently removed in a short time. Since the powder is used, it is possible to regenerate the ferric chloride etching waste liquid with less impurities.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the elapsed time after the addition of iron powder and the nickel ion removal rate in the method of the present invention.

FIG. 2 is a graph showing the relationship between the amount of iron powder added and the nickel ion removal rate in the method of the present invention and a comparative example.

FIG. 3 is a graph showing the relationship between the elapsed time after the addition of iron powder and the nickel ion removal rate in the method of the present invention and a comparative example.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C01G 49/10 C01G 49/14

Claims (1)

(57) [Claims] 1. A ferric chloride etching waste liquid containing nickel ions at a temperature of 50 ° C. or more, and a porous iron powder added to the ferric chloride etching waste liquid at least 1.5 times the weight of nickel in the ferric chloride etching waste liquid. Then, after the nickel ions are reduced and precipitated, a solid substance in the ferric chloride etching waste liquid is separated, and then the ferric chloride etching waste liquid is oxidized and concentrated. How to regenerate etching waste liquid.