JP2010221088A - Method of recycling waste material having metal plating layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recycling a waste material having a metal plating layer which enables recovering, individually with high efficiency, a target substrate and metal components of a metal plating formed on the surface of the target substrate and recycling them without excessive costs for treatment and equipment so as to utilize resources. <P>SOLUTION: The method is for recycling the waste material in which a metal plating layer is formed on the surface of a metal-, ceramic- or plastic-made substrate, and includes an acid pickling process of treating the waste with hydrochloric acid to remove metal compounds on the surface of the metal plating layer, and a plating layer removal process of dissolving the metal plating layer of the acid-pickled waste by using a solution of ferric chloride optionally added with hydrochloric acid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention separately collects and reuses metal, plastic, or ceramic target substrates and the metal components of the metal plating applied to the surfaces of the target substrates from the waste material subjected to metal plating. The present invention relates to a method for recycling a waste material on which a plating layer is formed.

Conventionally, parts or products that have been subjected to metal plating on the surface of a metal, plastic, or ceramic target substrate that has been molded into the shape of the final product (that is, a metal plating work or a composite material with metal plating) ) Is often used (see, for example, Patent Documents 1 to 3).
When the target substrate is made of metal, used parts and products are dissolved and reused, and when the target substrate is made of plastic or ceramics, they are discarded by incineration or landfill. In addition, when the surface of the metal plating layer is further coated, the coating may be dissolved and removed using a solvent.

JP 2004-285552 A Japanese Patent Laid-Open No. 2005-200687 JP 2005-336614 A

However, when a metal target substrate is dissolved and reused, the metal plating is also dissolved together with the target substrate, and the components of the metal plating are mixed into the target substrate and become an impurity component. For example, high-purity parts and products There was a fear that it could not be used as a raw material. In addition, in order to improve purity, it can also refine | purify in a some process process, However In this case, processing cost increased and it was not economical.

Moreover, when discarding the target substrate made of plastic or ceramics, not only the metal constituting the metal plating but also plastics and ceramics, which are resources, are discarded, so that effective use of resources cannot be achieved.
In addition, about the object base made of plastic, it can be considered that the metal plating is peeled off and reused. However, if the surface of the metal plating is coated, This could damage the plastic and reduce the quality. In addition, equipment for treating the solvent is required, and there is a problem that equipment cost and processing cost are required.

Therefore, the present applicant has intensively studied a technique for removing the plated metal from the target substrate made of plastic or ceramic using a ferric chloride solution or a ferric chloride solution to which hydrochloric acid is added. However, when a metal compound is formed on the surface due to oxidation of a part of the plating layer formed on the object, the metal compound is dissolved only by treatment with ferric chloride solution. It was found that the ferric chloride solution passed through the defective portion of the outermost surface layer of the plating layer, reached the metal plating layer, contacted the plating metal, and the dissolution of the plating metal proceeded. Therefore, this process determines the overall dissolution rate, and a sufficient dissolution rate of the plated metal cannot be obtained. Moreover, the undissolved part remains in the surface layer of the plating layer, and the subsequent cleaning process still has a problem that requires a large amount of cleaning liquid and labor.

The present invention has been made in view of such circumstances, and removes the target substrate and the metal component of the metal plating applied to the surface of the target substrate, even if there is a metal compound on the surface, processing costs. To provide a method for recycling waste materials with a metal plating layer that can be collected and reused individually with high efficiency and can effectively use resources without excessive costs and equipment costs Objective.

The recycling method of the waste material in which the metal plating layer according to the first invention according to the above object is formed is a recycling method of the waste material in which the metal plating layer is formed on the surface of a metal, ceramic, or plastic substrate. A method of
The waste material is treated with hydrochloric acid to remove a metal compound (including oxides and hydroxides of the plating metal) on the surface of the metal plating layer, and the waste material subjected to the pickling treatment is chlorinated. A plating layer removing step of dissolving the metal plating layer using a ferric chloride solution (ferric chloride solution) or a ferric chloride solution to which hydrochloric acid is added.
In addition, although sulfuric acid, nitric acid, etc. are applicable instead of hydrochloric acid, in the case of hydrochloric acid, since neutralization is easy and the post-treatment of a waste liquid is very easy, it was used as a liquid for removing a metal compound. Moreover, it is good to employ | adopt the density | concentration of hydrochloric acid 10 mass% or more (preferably 10 or 15 mass% or more and 35 mass% or less).

Further, a method for recycling waste material in which a metal plating layer according to the second invention is formed is a method for recycling waste material in which a metal plating layer is formed according to the first invention, wherein the substrate is made of metal. The metal base is one or more of iron, steel, copper, zinc, aluminum, magnesium, and alloys thereof.

A method for recycling waste material in which a metal plating layer according to a third invention is formed is a method for recycling waste material in which a metal plating layer is formed according to the first invention, wherein the substrate is made of plastic. The plastic substrate is made of nylon, polyacetal, modified polyphenylene ether, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyamide, polyether sulfone, liquid crystal polymer, polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin , Acrylonitrile styrene copolymer resin, MBS resin, and any one or more of these polymer alloys or polymer blends.

The waste material recycling method in which the metal plating layer according to the fourth invention is formed is the waste material recycling method in which the metal plating layer according to the first to third inventions is formed. The plating metal is recovered from the ferric chloride solution recovered in step 1 or the ferric chloride solution to which hydrochloric acid is added.

A waste material recycling method in which the metal plating layer according to the fifth invention is formed is a waste material recycling method in which the metal plating layer according to the fourth invention is formed, wherein the metal component of the metal plating layer is Iron powder is added to the dissolved waste liquid, the chloride dissolved in the waste liquid is replaced, and the metal component is separated and recovered.

And the recycling method of the waste material in which the metal plating layer which concerns on 6th invention was formed is the said metal plating in the recycling method of the waste material in which the metal plating layer which concerns on 1st-5th invention was formed. The surface of the layer is further coated with a paint or film, and after removing the paint or film with high-pressure water, the metal plating layer is removed. The water pressure of the high-pressure water is preferably 50 MPa or more and 400 MPa or less.

The method for recycling a waste material on which a metal plating layer according to the first to sixth inventions is formed is an acid that treats the waste material with hydrochloric acid to remove metal compounds (including other compounds) on the surface of the metal plating layer. A washing step and a plating layer removing step of dissolving the pickled waste material using a ferric chloride solution or a ferric chloride solution to which hydrochloric acid is added. The metal compound formed on the surface is removed with hydrochloric acid to expose the metal plating layer, and then the metal plating layer is dissolved with a ferric chloride solution.
Accordingly, the entire processing time can be shortened, and cleaning after removal of the metal plating layer is facilitated. In addition, the metal compound on the surface of the metal plating layer also dissolves in hydrochloric acid as metal ions and is easy to recover.

Furthermore, since the metal plating layer is removed from the surface of the substrate (same as the “target substrate”), a high-purity material in which the metal component of the metal plating layer is not mixed when the substrate is reused can be obtained. For this reason, for example, in order to obtain a high-purity material, it is not necessary to purify the material in a plurality of processing steps, so that the processing cost can be reduced and the workability can be improved.

In particular, in the method for recycling waste materials in which the metal plating layers according to the fourth and fifth inventions are formed, the base material from which the metal plating layers have been removed can be recovered, and ferric chloride solution or hydrochloric acid is added. Since the plating metal can be individually recovered and reused from the ferric chloride solution waste solution, resources can be effectively used.

And the recycling method of the waste material in which the metal plating layer which concerns on 6th invention is formed, before the metal plating layer is removed, when the surface of the metal plating layer is further coated or coated, Alternatively, since the film is previously removed with high-pressure water, it is possible to prevent impurities from being mixed into the base and the metal component of the metal plating layer. As a result, a high-purity target substrate and metal components can be obtained, and post-treatment of each material becomes unnecessary. In particular, even when a plastic target substrate is coated, it is not necessary to use a solvent for dissolving the coating, so that the quality of the target substrate can be prevented from being lowered and reused.

It is explanatory drawing of the recycling method of the waste material in which the metal plating layer which concerns on one embodiment of this invention was formed. It is explanatory drawing of the metal plating installation thing which concerns on an Example.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIG. 1, the method for recycling a waste material on which a metal plating layer is formed according to an embodiment of the present invention treats the waste material on which metal plating has been performed with hydrochloric acid to treat metal on the surface of the metal plating layer The pickling process which removes a compound, and the plating layer removal process which dissolves a metal plating layer using the ferric chloride liquid or the ferric chloride liquid to which hydrochloric acid was added to the pickled waste material. These will be described in detail below.

Recycled metal plating work (hereinafter also referred to simply as plating work) is a used part or product. For example, a defective product (for example, a non-inspected product) generated in the manufacturing process of the part or product. Acceptable products) and remaining materials. Specifically, the substrate (target substrate) from which the metal plating layer has been removed is made of metal, ceramic, plastic, or a mixture thereof.

Examples of metal target substrates include iron, steel, copper, zinc, aluminum, magnesium, and alloys of these metals (alloys containing the above metals as a main component, that is, 80% by mass or more, and further 90% by mass or more). 1) or two or more.
In addition, the ceramic target substrate is made of any one or more of alumina, silica, magnesia, mullite, and zirconia, for example.
The target base material made of plastic is (1) engineering plastic or super engineering plastic, (2) polyolefin resin (s), (3) polymer alloy or polymer blend of these plastics, and the like. In addition, what was comprised by any 1 or 2 or more of these (1)-(3) may be used.

The above (1) engineering plastic or super engineering plastic includes (a) nylon, polyacetal, modified polyphenylene ether, polycarbonate, (b) polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, (c) polyamide, polyether sulfone, Liquid crystal polymer, etc.
(2) Polyolefin resin (s) includes (a) polyethylene, polypropylene, polyvinyl chloride, polystyrene, (b) acrylonitrile butadiene styrene copolymer resin (ABS resin), (c) acrylonitrile styrene copolymer resin, methyl And methacrylate butadiene styrene copolymer resin (MBS resin).

Of the above-mentioned plastics, particularly preferred are rubber-containing styrene resins such as rubber-reinforced polystyrene (HI resin), ABS resin, MBS resin, etc. using the above-mentioned polystyrene, and ABS resin is particularly advantageous. . This is because metal plating is easy, moldability is good, and it is widely used as an inexpensive general-purpose resin with appropriate physical properties (for example, hobby entertainment related products such as pachinko and throttle machines). It is because it is easy to collect.
The purpose of metal plating on plastic is to obtain the hardness, luster, thermal conductivity, high-quality feeling, etc. of the metal that plastic originally does not have. , Door handles, grills, foil caps, emblems, etc.

The surface of these target substrates is subjected to metal plating composed of a single metal, two or more metals, or a metal component of an alloy.
Here, the single or two or more kinds of metals include, for example, copper, nickel, chromium, tin, lead, ruthenium, aluminum, or indium. The two or more kinds of metals are, for example, the case where two or more kinds of metals are laminated and plated in a plurality of layers as in the case of performing electroless plating of copper and further electroplating nickel. Metal is included.
Examples of the alloy include an alloy mainly composed of copper, nickel, chromium, tin, lead, or ruthenium (for example, 80% by mass or more, and further 90% by mass or more).
These metal platings may be formed using any of the conventionally known electroplating and electroless plating methods, and are formed using CVD (chemical vapor deposition), PVD (physical vapor deposition), or the like that does not use a plating bath. It may be done.

A method for removing the metal plating layer (that is, the plating metal) from the surface of the target substrate described above will be described with reference to FIG.
First, as shown in FIG. 1, a metal plating work (waste material) subjected to metal plating is washed with water to remove dust and dirt attached to the surface of the metal plating layer.
In addition, although the metal plating construction object to which metal plating was given may be wash-processed as it is, it is good to put it in a basket. In this case, when the target substrate is made of plastic, for example, using a conventionally known crusher, it is preferable to perform crushing treatment (coarse crushing) in advance so that one side has a size of about 10 cm, for example. .

When the surface of the metal plating layer is coated (or a film is affixed), the coating (film) is removed with high-pressure water and then washed. The water pressure of the high-pressure water refers to the pressure after the pressure is increased by a pump or the like, for example, 50 MPa or more and 400 MPa or less (preferably, the lower limit is 100 MPa, the upper limit is 300 MPa, and further 220 MPa). Hereinafter, the result of adjusting the water pressure to 100 to 180 MPa and performing a paint removal test will be described.

When the coating was a single color such as black or white, the coating could be easily peeled off by setting the water pressure to 100 MPa. In particular, in the case of white, peeling was possible even at 100 MPa or less.
On the other hand, in the case of metallic (silver, peach, ocher), the coating could be peeled off by setting the water pressure to 120 MPa or more.
The shape of the cleaning nozzle that ejects high-pressure water may be any of a conventionally known sector shape, eccentric rotation, center rotation, and the like. Using these various nozzles, we were able to confirm that the coating on the surface of the metal plating could all be removed by setting the water pressure of the high pressure water, the distance to the metal plating construction, and the spraying time of the high pressure water, respectively ( Above, water washing process, step S1).

Thereafter, the washed metal plating construction is immersed in a hydrochloric acid solution. As the hydrochloric acid solution, a solution containing 10 to 35% by mass (more preferably 15 to 35% by mass) hydrochloric acid is preferably used, but the present invention can be applied even when the concentration is higher.
Thereby, the metal compound formed on the surface of the metal plating layer can be dissolved and removed. Here, sulfuric acid or nitric acid can be used in place of hydrochloric acid, but hydrochloric acid is easier to post-treat. In this case, the pickling time with hydrochloric acid is preferably about 4 to 10 minutes at room temperature, but varies depending on the concentration (pickling step, step S2).

Next, the washing (pickling) -treated metal plating construction object is immersed in a ferric chloride solution or a ferric chloride solution to which hydrochloric acid is added, and the metal plating is dissolved in the ferric chloride solution. In addition, when dissolving metal plating in a ferric chloride solution, it is preferable to immerse (for example, about 8 to 30 minutes) a metal plating construction that has been cleaned in the ferric chloride solution. The metal plating layer on the surface of the plating work may be continuously sprayed with ferric chloride liquid or continuously contacted (dropping or flowing liquid).

Here, the concentration of ferric chloride (FeCl ₃ ) in the ferric chloride solution to be used may be approximately 10% by mass or more (preferably 30% by mass or more), but 60% by mass in consideration of economy. % Or less (preferably 55% by mass or less).
Further, hydrochloric acid (HCl) can be further added to the ferric chloride solution. In this case, the concentration of hydrochloric acid is preferably 5% by mass or more and 20% by mass or less. In addition, adding hydrochloric acid to the ferric chloride solution increases the overall cost of the treatment liquid and increases the amount of the post-treatment liquid. For plating metals that can be easily removed only with a ferric chloride solution, It is preferable to omit it.

The ferric chloride solution and the ferric chloride solution to which hydrochloric acid has been added include a newly produced new solution (including a regenerated solution) and a waste solution after using the new solution (for example, copper chloride or Either a solution in which nickel chloride is dissolved or a solution in which ferrous chloride is present can be used.
As a result, various metals in the metal plating form chlorides and dissolve in the ferric chloride solution.

Specifically, copper is copper chloride (CuCl ₂ ), nickel is nickel chloride (NiCl ₂ ), chromium is chromium chloride (CrCl ₃ ), tin is tin chloride (SnCl ₂ ), lead is lead chloride (PbCl ₂ ), Ruthenium is ruthenium chloride (RuCl ₃ ), aluminum is aluminum chloride (AlCl ₃ ), and indium is indium chloride (InCl ₃ ). In this way, by dissolving the metal plating in the ferric chloride solution, a target substrate free of metal plating is obtained (the plating layer removing step, step S3).
If the target substrate from which the metal plating layer has been removed is plastic, then it is washed with a weak acid and washed with water to remove the adhering ferric chloride solution (step S4). If necessary, the target substrate is dehydrated (step S5) and the crushing process is performed.

Here, when the target substrate is made of metal, for example, after removing the ferric chloride solution, it can be dissolved and reused as a raw material (step S8). Depending on the type of metal (for example, iron-based metal), after removing the metal plating, the liquid draining process may be performed as it is, and then the dissolution process may be performed.
In the case of ceramics, after the dehydration treatment after the water washing treatment, for example, the damaged portion can be repaired with a ceramic material, or pulverized and mixed with other raw materials (step S9).
In the case of plastic, for example, it is pulverized to an appropriate size of 1 to 10 mm and separated and used as it is as a raw material, or mixed with an appropriate amount of virgin material (unused material), and further heated. And can be melted into pellets (step S7).

On the other hand, the metal component of the metal plating dissolved in the ferric chloride solution is precipitated and recovered from this ferric chloride solution (waste solution). As this method, a conventionally known method can be used. For example, when the metal component of the metal plating contains copper and nickel, for example, the method described in JP-A-6-127946 can be used. The same method can be used for tin, silver, indium, and the like. Note that chromium and aluminum are recovered as hydroxides.
Since this specific method is described in the publication, it will be briefly described below.

Iron powder is added to the ferric chloride solution containing the above-described metal components to replace copper chloride (chloride) dissolved in the ferric chloride solution, and copper is deposited and separated and recovered. If ferric chloride remains in the ferric chloride solution, it is preferable to add iron powder and reduce it to ferrous chloride first, because the copper recovery efficiency is improved. .
Next, iron powder is added to the copper removal liquid from which copper has been removed, and the iron ion concentration is controlled to precipitate and separate and recover nickel.
Thereby, copper and nickel can be recovered from the ferric chloride solution.
By recovering the target substrate and the metal components of the metal plating by the above method, these can be reused, so that resources can be effectively used.

Next, examples carried out for confirming the effects of the present invention will be described.
Here, as shown in FIG. 2, copper and nickel are plated on the surface of the base material 10 made of ABS resin as a plastic metal plating work 10a (specifically, an example of a front grill for automobiles and waste materials). (Or copper plating) 11 is formed. A nickel base plating 12 is further formed thereon, and a chromium plating 13 is further formed thereon. The copper and nickel plating is formed on the surface of the target substrate 10 by electroless plating and electroplating, respectively. A metal compound 14 is formed on the surface of the chromium plating 13.

200 kg of the metal plating construction object 10a on which the metal plating layer is formed as described above is put in a basket, and the concentration is 10% by mass or more (in this example, 30 to 35% by mass). Soaked to the extent (5 minutes in this example). Thereby, the metal compound formed on the surface of the chromium plating was dissolved in hydrochloric acid and removed. In addition, although this process was performed at normal temperature, you may heat.

Next, the pickled metal plating work 10a is immersed in a ferric chloride solution having a temperature from room temperature to 60 ° C. (55 ° C. in this embodiment) as it is, and the metal plating is made into a ferric chloride solution. Dissolved. This test was performed a total of 8 times. The ferric chloride concentration of the ferric chloride solution used was 40-50% by mass (average of 8 times is 45% by mass), and the immersion time in the ferric chloride solution was 8-15 minutes (average 10). Minutes).

Next, the target substrate was taken out of the ferric chloride solution, and the ferric chloride solution adhering to the surface of the target substrate was removed in the order of washing with water, washing with hydrochloric acid, and washing with water. In addition, hydrochloric acid washing | cleaning was performed for 6 minutes per time using the washing | cleaning liquid whose hydrochloric acid concentration is 10 mass%. In addition, washing was performed to such an extent that water was evenly flowed over the surface of the target substrate.
Thereby, the object substrate without metal plating adhesion was obtained. It was confirmed that the surface accuracy and physical properties (tensile strength, tensile elongation, Izod impact strength) of this target substrate were equivalent to those of unused ABS resin.

[Comparative example]
Next, an experiment of removing the metal plating layer with only ferric chloride solution was performed by omitting the step of first washing the metal plating construction object 10a with hydrochloric acid.
The same ferric chloride solution (45% by mass) as that used in the example was used. However, when the immersion time was about 10 minutes, it was difficult to remove the metal plating layer. As a result, the metal plating layer was largely removed, but a large amount of undissolved residue remained in the ferric chloride solution. The main component of this unmelted residue is presumed to be a metal oxide.

From the above, by using the recycling method of the waste material in which the metal plating layer of the present invention is formed, the object substrate and the metal plating can be removed from the metal plating construction work without excessive processing costs and equipment costs. It was confirmed that metal components can be collected and reused individually, and resources can be used effectively. That is, hydrochloric acid is highly soluble in oxides and hydroxides, but the plating metal has low solubility. In addition, ferric chloride solution has low solubility in oxides and hydroxides (that is, it is difficult to erode), but it has been found that it has a high dissolving power for plated metal, and this is used as a metal-plated waste material. Apply and separate each.

In addition, although it showed about the case where a ferric chloride liquid was used here, it has confirmed that a favorable result was obtained also when the ferric chloride liquid to which hydrochloric acid was added was used. However, if hydrochloric acid and ferric chloride are separated, each solution can be used repeatedly independently, which is more efficient.
Moreover, although the case where the object base material recycled the product of plastic was demonstrated, it has confirmed that a favorable result was obtained also about the product comprised from the metal or ceramics.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, the case where the waste material recycling method in which the metal plating layer of the present invention is formed by combining a part or all of the above-described embodiments and modifications is included in the scope of the right of the present invention.

10: object substrate (ABS resin), 10a: metal plating construction, 11: copper and nickel plating, 12: nickel base plating, 13: chromium plating, 14: metal compound

Claims (6)

A method for recycling waste material in which a metal plating layer is formed on the surface of a metal, ceramic, or plastic substrate,
A pickling process in which the waste material is treated with hydrochloric acid to remove a metal compound on the surface of the metal plating layer;
A metal plating layer characterized by having a plating layer removing step of dissolving the metal plating layer using the ferric chloride solution or the ferric chloride solution to which hydrochloric acid is added to the waste material subjected to the pickling treatment Recycling method for waste materials that have been formed. 2. The method for recycling waste material according to claim 1, wherein the base is made of metal, and the base is made of iron, steel, copper, zinc, aluminum, magnesium, and the like. A method for recycling a waste material on which a metal plating layer is formed, wherein the metal plating layer is any one or more of these alloys. 2. The method for recycling waste material according to claim 1, wherein the substrate is made of plastic, and the plastic substrate is made of nylon, polyacetal, modified polyphenylene ether, polycarbonate, polyethylene terephthalate, poly Butylene terephthalate, polyphenylene sulfide, polyamide, polyether sulfone, liquid crystal polymer, polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin, acrylonitrile styrene copolymer resin, MBS resin, and any of these polymer alloys or polymer blends 1 or 2 or more, A method for recycling a waste material having a metal plating layer formed thereon. In the recycling method of the waste material in which the metal plating layer of any one of Claims 1-3 was formed, the ferric chloride liquid collect | recovered at the said plating layer removal process or the ferric chloride liquid to which hydrochloric acid was added A method of recycling waste material on which a metal plating layer is formed, characterized in that the plating metal is recovered from the waste liquid. 5. The method of recycling waste material with a metal plating layer formed thereon according to claim 4, wherein iron powder is added to the waste liquid in which the metal component of the metal plating layer is dissolved, and chloride dissolved in the waste liquid is replaced. Separating and recovering the metal component, and a method for recycling waste material having a metal plating layer formed thereon. 6. The method for recycling waste material on which a metal plating layer according to claim 1 is formed, wherein the surface of the metal plating layer is further coated with a coating or film, and the coating or film is subjected to high pressure. A method for recycling waste material on which a metal plating layer is formed, wherein the metal plating layer is removed after removing with water.

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