JPH1176980A - Treatment of printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate and recover metals and nonmetals in a waste printed board by heating a waste printed board to generate gas from resinous materials in the board and to weaken component-integrating functions in the board, and then, mechanically crushing the resulting weakly-integrated waste printed board by applying external force to the board. SOLUTION: In this treatment, a waste printed board 1 is charged into a board heating device 2 to heat the board 1, wherein, although the board heating temp. somewhat depends on the kind of the board 1, as this temp., any temp. within the range of 270 to 450 deg.C may be adopted. In this board heating device 2, resinous materials in the board 1 are converted, and concurrently, gas is generated from the resinous materials and discharged as waste gas 7. Accordingly, in the waste printed board 1 thus heat-treated, the integration of metallic components such as gold platings, copper foils and copper wires, with nonmetallic inorganic materials such as glass wool is weakened. However, sometimes, copper through-holes formed by plating, or the like, fine copper wires, etc., and these different kinds of materials are bound to each other. Therefore, the heat-treated waste printed board 1 is further crushed by a crusher 3 to easily separate metals and nonmetallic inorganic materials from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a waste printed circuit board, and more particularly to a method for separating and recovering metals and nonmetals from a waste printed circuit board.

[0002]

2. Description of the Related Art What is important in recycling and recycling is separation and sorting of materials to be recycled by material. However,
It is difficult to sort waste printed circuit boards made of metals, non-metallic inorganic substances and resins by material. Therefore, waste printed circuit boards are conventionally shredded with electronic components and harmful solder attached, and are mostly landfilled at final disposal sites.Therefore, there is little recovery of metals such as gold and copper. There is hardly any effective recycling. Generally, the following is known as recycling of a waste printed circuit board.

The first problem is that, as described in Japanese Patent Application Laid-Open No. 2-88725, a waste printed circuit board is supplied with air at a temperature from 800 ° C. or higher to the melting temperature of copper so that the resin component is ignited to carbon. And then pulverize to separate and collect copper.

[0004] As described in JP-A-6-228667, printed circuit boards are crushed in coarse and fine crushing steps.
This is a method in which the obtained pulverized material is separated into a portion containing a large amount of a metal component and a portion made of a resin, a filler, or the like by specific gravity separation and collected.

[0005] No. 3 is that, as described in JP-A-6-256863, the printed circuit board is placed in a reducing atmosphere at 450 ° C to 1 ° C.
Dry distillation in a temperature atmosphere of 000 ° C, cool the residue to a temperature where it is not rapidly oxidized even if it comes into contact with the atmosphere, and then pulverize. It is a method of separating

No. 4, as disclosed in Japanese Patent Application Laid-Open No. 6-296957, discloses a structure in which a waste printed board on which components are mounted is heated in an atmosphere containing oxygen to oxidize a metal component, and finely pulverized by a pulverizing process. This method is used as a filler in materials, building materials and insulating materials.

No. 5 discloses a method of cutting a waste copper-clad laminate as described in Japanese Patent Application Laid-Open No. 7-75771, and colliding with each other in a floating state while heating and holding the resin in a temperature range where the resin returns to its original state when heat is removed. Then, it is a method of separating into copper and other components.

[0008]

However, each of the above methods has the following problems.

The method 1 heats to a high temperature of 800 ° C. or more, which consumes a large amount of energy. In this temperature range, metals such as gold and copper are reinforced by non-metals such as glass fibers in a substrate. Reacts with materials and vitrifies. Re-smelting vitrified metals requires high energy consumption and low recovery efficiency.

In the method described in No. 2, since the non-metallic material such as metal or glass wool is in close contact with the resin, the strength of the object to be pulverized is high, and it is very difficult to finely pulverize the substrate. difficult. Therefore, it is necessary to use a special crusher, which increases the processing cost. In addition, since metal materials such as gold and copper are tightly adhered to resin and glass fiber, many metals do not separate from resin even when finely pulverized, so the recovery rate is low, and the metal and resin are separated even after recovery. Need to be performed.

The method of the third method consumes a large amount of energy similarly to the method of the first method, and the metal reacts with the glass in the above temperature range to vitrify, so that the recovery efficiency is low.

The method described in No. 4 uses a finely pulverized material as it is as a filler without recovering the metal, and the field of application is limited.

The method shown in No. 5 is difficult to cut because it is left untreated, and it is necessary to use a special cyclone to collide with each other in a floating state. Further, this method is to separate metals by the energy of collision between cut substrates without applying a mechanical external force. The cut substrate is light, and with wind power alone, it is questionable that even if the cut substrates are caused to collide with each other in a cyclone, energy is applied to separate the metal from the substrate.

[0014]

SUMMARY OF THE INVENTION A waste printed board processing method according to the present invention is directed to a waste printed board formed of a resin, a metal, and a nonmetallic inorganic substance. In order to recycle waste, it is convenient to separate each component material.However, on printed circuit boards, various inorganic substances including metals and resins are integrated by physical and chemical bonding. And cannot be separated by ordinary methods.

In the present invention, it has been found that the most reliable and efficient separation of constituent materials in such a printed circuit board is to separate metal and nonmetal, and furthermore, a method for realizing this idea has been found. .

The point of waste printed circuit board separation lies in the resin. The resin integrates the entire printed circuit board. However, by heating at an appropriate temperature according to the present invention, the resin itself generates gas and changes irreversibly. When the resin changes in this manner, the action of integrating the resin can be reduced, and the separation of the waste printed circuit board becomes easy. At the same time, the resin strength enhancing component contained in the resin is gasified, thereby greatly reducing the resin strength. The gasification of the resin may be performed in an air atmosphere or an inert atmosphere such as nitrogen. The heating temperature is important.
The heating temperature according to the present invention is preferably from 270 to 450 ° C. If the heating temperature is lower than the optimum temperature, no gas is generated from the resin, which is not preferable. Above 450 ° C., copper in the printed circuit board and a nonmetallic inorganic substance such as glass wool react to form a compound, which makes separation of metal and nonmetallic inorganic substance extremely difficult, which is not preferable. It should be noted that the reaction and compounding of the metals constituting the printed circuit board do not adversely affect the recovery of the metal.

When the waste printed circuit board having a reduced integration function is mechanically subjected to external force and crushed by the above-described optimal heating, metal and nonmetallic inorganic substances in the waste printed circuit board are efficiently separated and recovered. It becomes possible. Inside the printed circuit board, there are a large number of small copper pipes, copper fine wires, and copper foils that constitute through holes, and these are geometrically intricately intertwined as a combination of a nonmetallic inorganic material such as glass wool and a different material. . For separating metals, a force for cutting and loosening them is necessary, and crushing by mechanically applying external force is this force. For example, mass processing can be performed by crushing with a cutter. Since the heat treatment reduces the integration power and strength of the waste printed circuit board, crushing by a cutter which usually has a large power and low productivity can be extremely smoothly crushed in the present invention. When crushing is not performed by applying a mechanical external force from outside the waste printed circuit board, the separation force is low, and the separation rate is lowered, which is not preferable. In order to crush by applying an external force mechanically, the temperature must be 250 ° C. or less. If the temperature is higher than 250 ° C., the crushing ability of the crusher for applying an external force is not sufficiently exhibited, so that the separation performance is inferior.

Various methods can be used to sort the separated crushed product by mechanically applying an external force to the waste printed circuit board.
In particular, it is preferable to use at least one or more of the three types of screening methods, namely, the sieving method, the wind power screening method, and the eddy current screening method. In the crushing by the heat treatment and the application of the external force according to the present invention, it has been found that the crushing size is different, that is, the smaller the metal and the non-metal are, the less the ductility is based on the ductility of the material. Therefore, the sieving method is an effective method. Further, in the present invention, since the metal and the non-metal of the waste printed circuit board are separated, the properties that the metal has a higher specific gravity than the non-metal and that the metal is selectively separated by eddy current can be applied. Sorting by the sorting method and the eddy current sorting method is possible. This is an effect of the present invention that aims at separation of metal and nonmetal. Therefore, the wind sorting method and the eddy current sorting method using the specific gravity difference are important parts in the present invention.

In the heat treatment, the resin constituting the printed circuit board changes to generate gas. Since the gasification component contains a resin reinforcing component, the resin is simultaneously softened to facilitate the subsequent crushing treatment. Halogen compound gas containing bromine and the like in the gasification component can be neutralized with an alkaline solution when heated to a temperature at which hydrocarbon components in the gas are almost decomposed.

If the above-mentioned invention is systemized, it becomes possible to efficiently treat a waste printed circuit board. Further, in the case of processing many products and parts, when a difficult-to-process object such as a printed circuit board is included, the presence thereof makes the processing of the products and parts itself difficult. However, if the system according to the present invention is provided during processing of many products and parts, many products and parts can be effectively processed. This is the solution intended by the present invention. Therefore, a processing system for processing the entire product or component including the waste printed circuit board including the system according to the present invention also corresponds to the present invention.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments.

FIG. 1 shows a waste printed circuit board processing system process according to an embodiment of the present invention. The configuration of the process shown in FIG. 1 includes a waste printed circuit board 1, a substrate heating device 2, a crusher 3, a wind separator 4 attached to the crusher 3, a wind separator 11, a blower 11a, a collecting pot 5, and a collected pot. Copper foils 5a, recovered gold-plated portion 5b, recovery pot 6 centered on non-metallic inorganic material 6, recovered glass wool material 6
a, recovered resin residue 6b, exhaust gas 7, exhaust gas heating device 8, neutralization treatment device 9, neutralization treatment tank 9a, neutralization solution collection tank 9b, neutralization solution 9c, neutralization solution circulation pump 9d, It comprises a shower nozzle 9e, an exhaust pump 9f, harmless exhaust gas 10, and an exhaust port 12.

As shown in FIG. 3, the printed circuit board is composed of a non-metallic inorganic substance such as glass wool, an epoxy resin, a copper foil serving as a conductor circuit, and the like in a complicated manner.
It also has a number of copper pipes that make up through holes.

The waste printed board 1 is put into a board heating device 2. Here, the substrate heating temperature may be 270 ° C. or more and 450 ° C. or less, though it depends on the type of the substrate. 270 ° C
If the temperature is lower than this, the reaction and change rate of the resin in the substrate are extremely slow, which is not practical. On the other hand, if the temperature exceeds 450 ° C., the metal in the substrate and the glass wool material start reacting, and the metal is vitrified. Is not suitable because the recovery rate is significantly reduced.
The resin content in the waste printed board 1 is changed by the board heating device 2 and gas is generated at that time. These are exhausted as exhaust gas 7, and the waste printed circuit board 1 is less integrated with metal parts such as gold plating, copper foil and copper wire and nonmetallic inorganic substances such as glass wool. However, copper through-holes and thin copper wires formed by plating or the like may combine these different materials. Here, when the waste printed circuit board 1 is subjected to the crusher 3, metals and nonmetallic inorganic substances are easily separated.
Here, as the crusher 3, for example, the one shown in FIG. 2 is preferable. When there are many through holes, a crusher using a cutter is convenient. When a large number of electronic components are mounted on the substrate, it is also preferable to use a coarse crusher in the preceding stage. Most nonmetallic inorganic substances are glass wool. The metal parts are mostly gold-plated copper wire and copper foil, copper foil, copper fine wire, and copper through-hole pipe. Most of the glass wool is collected in a collection pot 6 by a wind separation device 4 using a wind generated at the time of crushing. Separates that are not collected in the collection pot 6 are applied to the wind separation device 11, whereby the wind is blown by the blower 11 a, so that mainly the metal is collected in the collection pot 5 and the nonmetallic inorganic substance is mainly collected in the collection pot 6. Further, the exhaust gas 7 generated by the reaction and change of the resin component in the waste printed board 1 in the board heating device 2 is at least a hydrocarbon-based gas, but is formed by the reaction of the flame retardant in the waste printed board 1. Because it contains halogenated hydrocarbons such as methyl bromide and ethyl bromide,
This is heated in an atmosphere containing oxygen in the exhaust gas heating device 8 to cause all unburned hydrocarbons to react, and then introduced into the neutralization tank 9a. In the neutralizing solution tank 9a, the neutralizing solution 9c in the neutralizing solution collecting tank 9b is sucked by the neutralizing solution circulating pump 9d and jetted from the shower nozzle 9e. Here, the exhaust gas introduced from the exhaust gas heating device 8 is neutralized by the neutralizing solution injected from the shower nozzle 9e,
It is sucked by the exhaust pump 9f and discharged from the exhaust port 12. As the type of the neutralizing solution 9c, for example, there is an alkaline aqueous solution such as sodium hydroxide and calcium hydroxide. By doing so, the halogenated hydrocarbon becomes halogen, hydrogen halide, carbon dioxide and water.
For heating the exhaust gas, use of a heating furnace, an afterburner, or the like is conceivable. Exhaust gas from the exhaust gas heating device 8 is recovered in a neutralization treatment device 9 to make the gas harmless, and harmless exhaust gas 10 is released. By processing the printed circuit board by such a process, the metal can be efficiently separated and recovered.

Next, the experimental results will be described.

(1) Experiment 1 A sample from which solder and electronic components had been removed in advance from the waste material of a glass cloth epoxy resin printed board was heated from room temperature to 550 ° C. by differential thermal analysis, and the rate of weight loss was examined. FIG. 4 shows the results. Here, the weight loss corresponds to the amount of resin gasified by the resin. No weight loss is observed up to 260 ° C. Gas evolves from 270 ° C. and loses weight. 500
Above ℃, almost no gas was generated and the weight was reduced.

(2) Experiment 2 A sample obtained by removing solder and electronic components from waste glass cloth epoxy resin printed circuit boards having a size of 3 cm × 3 cm was used as a sample.
The sample was heated from 10 ° C. to 500 ° C. at 30 ° C. intervals for 30 minutes, each sample after heating was carefully decomposed, and the amount of metal reacted with glass wool was measured. FIG. 5 shows the results. No reaction was observed up to 450 ° C., but at 460 ° C. or higher, a reaction between the metal and glass wool was observed, and the amount increased with increasing temperature.

(3) Experiment 3 After removing solder and electronic components from waste materials of a glass cloth epoxy resin printed circuit board having a size of 23 cm × 19 cm in advance,
The substrate was heated in an air atmosphere at each temperature for 30 minutes using an electric furnace. Thereafter, an external force was mechanically applied to the substrate by a cutter type crusher, and thereafter, wind separation was performed, and the ratio of the metal constituting the substrate collected in the collection pot 5 was determined. Table 1 shows the results. At a heating temperature of 260 ° C., the resin in the substrate hardly changed even after heating for 30 minutes, and the substrate was cut by a cutter-type crusher, but the metal and the nonmetallic inorganic substance were not separated. However, if the heating temperature is 270
At ℃, the resin generated a large amount of gas and changed greatly. When crushed by a cutter-type crusher after heating, some of the nonmetallic inorganic substances were recovered in the recovery pot 5 because the copper wool and the through-hole part could not be separated from the glass wool, but most metals were recovered. It was able to be collected in the collection pot 5. At 300 ° C. and 400 ° C., the mixing ratio of the nonmetallic inorganic substance collected in the collection pot 5 was reduced. At 450 ° C,
Although the amount of metal collected in the collection pot 5 is slightly reduced, 90
% Metal recovery is possible. Here, the plated gold was partially peeled off by heating at 450 ° C., so that the recovery rate was reduced.

When the heating temperature reaches 460 ° C., which is higher,
The reaction of the metal with the glass wool begins, and the reaction starts to vitrify the metal. Therefore, the collection pot 6
Also begins to mix metal. As a result, the amount of metal collected in the collection pot 5 decreases. In addition, the non-metal mixing ratio in the collection pot 5 also increases. In particular, the gold-plated portion is peeled off and becomes together with the glass wool, and the amount collected in the collection pot 6 increases.

[0030]

[Table 1]

(4) Experiment 4 Next, an experiment concerning neutralization of exhaust gas generated during substrate heating was performed. After removing solder and electronic components from the waste material of the glass cloth epoxy resin printed circuit board having a size of 20 cm × 20 cm, the temperature is reduced from room temperature to 35 ° C. in an air atmosphere using an electric furnace.
Heated to 0 ° C. After air was added to the gas generated in this heating process, the gas was introduced into an exhaust gas heating furnace maintained at various temperatures, heated, and after heating, a 5-unit containing 0.1 N aqueous sodium hydroxide solution was heated. It was introduced into a gas washing bottle and neutralized.
Methyl bromide in the gas after exhaust gas heating and the gas after neutralization,
Brominated hydrocarbons such as ethyl bromide, and bromine and hydrogen bromide were quantitatively analyzed. Table 2 shows the results. The main component of the exhaust gas after the substrate is heated is a hydrocarbon-based gas, and bromine added to the substrate resin as a flame retardant is also discharged as a brominated hydrocarbon such as methyl bromide and ethyl bromide. This brominated hydrocarbon is hardly neutralized when passed through an alkaline solution. If this brominated hydrocarbon is completely burned into bromine and hydrogen bromide, it can be neutralized with an alkaline solution. However, at exhaust gas heating temperatures of 750 ° C. and 800 ° C., methyl bromide and ethyl bromide remained in the gas before neutralization, and were not neutralized. However, when the exhaust gas heating temperature was 850 ° C. or higher, methyl bromide and ethyl bromide almost completely became bromine and hydrogen bromide, and could be neutralized with an aqueous sodium hydroxide solution.

[0032]

[Table 2]

[0033]

As described above, according to the present invention, there is provided a waste printed board processing method capable of efficiently separating and recovering metal and non-metal from a waste printed board formed of at least a metal, a resin, and a nonmetallic inorganic substance. can do.

[Brief description of the drawings]

FIG. 1 is a view showing a waste printed board processing system process according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a crusher used in the processing method of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a printed circuit board.

FIG. 4 is a diagram illustrating a relationship between a heating temperature of a waste printed circuit board and weight reduction.

FIG. 5 is a diagram showing a reaction amount of metal and glass wool on a waste printed circuit board.

[Explanation of symbols]

1 ... waste printed circuit board, 2 ... substrate heating device, 3 ... crusher,
4 ... Wind sorting device, 5, 6 ... Recovery pot, 7 ... Exhaust gas, 8 ... Exhaust gas heating device, 9 ... Neutralization treatment device, 11 ...
Wind separator, 11a ... blower.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshio Yamashita 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. No. 1 Inside the Hitachi Research Laboratory, Hitachi, Ltd.

Claims (5)

[Claims] 1. A method of heating and treating waste printed circuit boards comprising a resin, a metal and a non-metallic inorganic substance, followed by pulverization to separate and recover the metal and the non-metallic inorganic substance. A method for treating a printed circuit board, wherein the method is performed at a temperature at which a gas is generated and the metal and the nonmetallic inorganic substance do not form a compound to generate a gas from the resin, and then crushed by a crusher. 2. The method according to claim 1, wherein the heating temperature of the printed board is set to 270 ° C. or more and 450 ° C. or less. 3. The method according to claim 1, wherein the temperature of the printed circuit board is reduced to 250 ° C. or less during the crushing. 4. The method according to claim 1, wherein a gas generated from the resin by heating the printed circuit board is recovered,
A process for heating a gas in an oxygen-containing atmosphere to decompose hydrocarbons contained in the gas, and then neutralizing a halogen compound remaining in the gas with an aqueous alkali solution. Method. 5. The method according to claim 1, wherein after the printed circuit board is crushed by the crusher, the metal is separated from the metal by using at least one of a sieving method, a wind screening method and an eddy current screening method. A method for treating a printed circuit board, wherein the method is for separating metal and inorganic substances.