JP6844398B2 - How to separate glass wool - Google Patents

Description

The present invention relates to a method for separating glass wool used when recycling heat insulating materials for refrigerators and the like.

Since the heat insulating performance of refrigerators and freezers is directly linked to the energy saving performance, high-performance heat insulating materials are being actively developed. Urethane heat insulating materials mainly made of rigid urethane foam (urethane foam) have been used as heat insulating materials for refrigerators. However, a considerable thickness is required to obtain the required heat insulating performance with urethane heat insulating material, and when applied to the wall of the refrigerator, the wall of the refrigerator becomes thick, and there is a limit to securing sufficient internal capacity. It was.

In recent years, a vacuum heat insulating material in which a core material made of glass wool is vacuum-packed with a packaging material such as aluminum foil has been developed for the purpose of improving the heat insulating performance of the refrigerator and ensuring sufficient internal capacity. It is used as a material. The amount of vacuum heat insulating material used in the total heat insulating material of the refrigerator tends to increase year by year, which contributes to the improvement of the energy saving performance of the refrigerator.

On the other hand, from the viewpoint of home appliance recycling, recycling of refrigerators and the like using urethane heat insulating materials and vacuum heat insulating materials in combination has many problems in terms of recycling cost and recycling efficiency. Generally, when recycling waste home appliances in a recycling factory, the waste home appliances are crushed by a crusher and processed into crushed products. After that, through separation and sorting processes such as wind power sorting and specific gravity difference sorting, the crushed material is sorted by material (metal, plastic, etc.) and reused as a recycled material. At that time, in the separation and sorting process, it is necessary to improve the purity of each material as much as possible in order to increase the added value of the recycled material. However, in a refrigerator in which the urethane heat insulating material and the vacuum heat insulating material are used in combination, the crushed material is a mixture of urethane foam and glass wool. There is a problem that it is difficult to separate and sort the crushed product in which urethane foam and glass wool are mixed into urethane foam and glass wool.

As a method of separating and sorting a crushed product in which urethane foam and glass wool are mixed into urethane foam and glass wool, there is a method of selecting glass wool from the crushed product by using magnetic force using iron powder mixed in the glass wool (for example). , Patent Document 1).

Further, a method of separating dust and the like adhering to glass wool by washing the glass wool with water containing a surfactant is disclosed (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2006-7712 (page 8, FIG. 4) International Publication WO 2005/035098 Pamphlet (pages 8-9, Fig. 1)

In the conventional method of sorting glass wool from crushed material using magnetic force, iron powder mixed in glass wool from other iron members when processing waste home appliances into crushed material is used. However, it is unavoidable that iron powder is mixed with members other than glass wool, and it is difficult to separate glass wool with high purity. Further, iron powder cannot be expected to be mixed in the crushed material obtained by separating and recovering only the heat insulating material from the refrigerator and crushing the heat insulating material, and glass wool cannot be selected from the crushed material containing only the heat insulating material.

Further, in the method of separating the dust and the like adhering to the glass wool by washing the glass wool with water containing a surfactant, the dust adhering to the surface layer of the glass wool can be removed. However, foreign matter entangled between the fibers of glass wool cannot be efficiently removed.

The present invention has been made to solve the above-mentioned problems, and it is possible to sort glass wool from crushed material having only a heat insulating material, and to efficiently remove foreign substances entangled between fibers of glass wool. It is an object of the present invention to provide a method for separating glass wool.

The method for separating glass wool according to the present invention is
A method for separating glass wool from a mixture of glass wool and urethane foam.
When a dispersion was prepared by dispersing the glass wool mixture in a solvent containing water and a dispersant and the weight of the dispersion was 100% by weight, the solid content concentration of the glass wool mixture was 3% by weight or more and 10% by weight or less. Dispersion liquid adjustment process and
A stirring process that stirs the dispersion and
A dilution step of adding water to the stirred dispersion to reduce the solid content concentration to 1% by weight or less, and
A vibration process in which ultrasonic vibration is applied to the diluted dispersion , and
It is provided with a separation step of separating the suspended matter and the sediment by allowing the dispersion liquid to stand after the vibration step.

The present invention comprises a stirring step of stirring a dispersion having a solid content concentration of 3% by weight or more and 10% by weight or less, and a dilution step of adding water to the stirred dispersion to bring the solid content concentration to 1% by weight or less. Since it is equipped with a vibration step of applying ultrasonic vibration to the diluted dispersion and a separation step of allowing the dispersion after the vibration step to stand still to separate suspended matter and sediment, only the heat insulating material is provided. Glass wool can be sorted from the crushed material of the glass wool, and even foreign substances entangled between the fibers of the glass wool can be efficiently removed.

It is a schematic diagram of the glass wool separation method which concerns on Embodiment 1 of this invention. It is a flowchart of the glass wool separation method which concerns on Embodiment 1 of this invention. It is a schematic diagram of the glass wool separation method which concerns on Embodiment 1 of this invention. It is a schematic diagram of the glass wool separation method which concerns on Embodiment 1 of this invention. It is a characteristic diagram of the glass wool which concerns on Embodiment 1 of this invention.

Embodiment 1.
The method for separating glass wool according to the first embodiment for carrying out the present invention will be described. In the present embodiment, a method of separating glass wool from a mixture of urethane foam and glass wool generated in the recycling process of the refrigerator will be described as an example.

In the refrigerator recycling process, the refrigerator is crushed. This crushed crushed product contains metal, plastic, and the like. This crushed material is separated into metals, plastics, etc. through specific gravity difference sorting and wind power sorting. When a refrigerator using both a urethane heat insulating material and a vacuum heat insulating material is crushed, a crushed product is produced in which the heat insulating material containing urethane foam as a main component and the heat insulating material containing glass wool as a main component are crushed at the same time. Therefore, some of the crushed products separated as plastics are a mixture of urethane foam and glass wool. The crushed product in which urethane foam and glass wool are mixed contains not only relatively large urethane foam but also fine urethane foam entwined between the fibers of the glass wool mass. The present embodiment is a method of separating glass wool from a crushed product in which urethane foam and glass wool are mixed.

The method for separating glass wool according to the present embodiment utilizes a floating / sink sorting method in water that utilizes the difference between the specific gravity of urethane foam and the specific gravity of glass wool. The true specific gravity of urethane is 1.1 to 1.2, but since urethane foam contains a large amount of air layer inside, the apparent specific gravity is 0.2 to 0.3. On the other hand, the specific gravity of glass wool is 2.2 to 2.6. Therefore, urethane foam floats in water having a specific gravity of 1, whereas glass wool settles in water.

FIG. 1 is a schematic view for explaining a method for separating glass wool in the present embodiment. In FIG. 1, the glass wool mixture 1 contains a coarse urethane foam 2 and a glass wool lump 5 containing the glass wool 3 and the fine urethane foam 4 entwined between the fibers of the glass wool 3. The glass wool mass 5 further contains bubbles (air layer) 6 between the fibers. In FIG. 1, the glass wool mixture 1 is dispersed in a solvent 7 containing water and a dispersant. The dispersion liquid 8 in which the glass wool lump 5 is dispersed in the solvent 7 is stored in the container 9 and is stirred by the stirring propeller 10. When the weight of the dispersion liquid 8 is 100% by weight, the solid content concentration of the glass wool mixture 1 is adjusted to 3% by weight or more and 10% by weight or less.

FIG. 2 is a flowchart for explaining a method for separating glass wool in the present embodiment. As shown in FIG. 2, in S1, as a dispersion liquid adjusting step, the glass wool mixture 1 is dispersed in a solvent containing water and a dispersant, and the solid content concentration of the glass wool mixture 1 is adjusted to 3% by weight or more and 10% by weight or less. adjust.

Next, in S2, the dispersion liquid is stirred as a stirring step. The state of the glass wool mixture 1 and the like in the steps of S1 and S2 is as shown in FIG.

Next, in S3, as a dilution step, water is added to the dispersion liquid, and when the weight of the dispersion liquid 8 is 100% by weight, the solid content concentration of the glass wool mixture 1 is adjusted to 1% by weight or less.

Next, in S4, ultrasonic vibration is applied to the dispersion liquid as a vibration step. FIG. 3 is a schematic view of a process of applying ultrasonic vibration to the dispersion liquid. In FIG. 3, ultrasonic vibration is applied to the dispersion liquid by placing the container 9 on the ultrasonic vibrator 11. By applying ultrasonic vibration to the diluted dispersion, fine urethane foam 4 entwined between the fibers of the glass wool mass is discharged to the outside of the glass wool, and bubbles (air layer) 6 between the fibers of the glass wool mass are discharged. Infiltrate water.

Next, in S5, as a separation step, after stopping the ultrasonic vibration, the dispersion liquid is allowed to stand to separate the suspended matter and the sedimented matter. FIG. 4 is a schematic view when the dispersion liquid is allowed to stand. As shown in FIG. 4, the coarse urethane foam 2 and the fine urethane foam 4 float because the apparent specific gravity is 0.2 to 0.3, which is smaller than that of water, and the glass wool 3 has a specific gravity of 2.2 to 2.6. Since it is larger than water, it sinks. By recovering this sediment, the glass wool 3 can be separated and recovered from the glass wool mixture 1.

The dispersant in the S1 step is not particularly limited as long as it can be used for an aqueous slurry, and those known in the art can be used. Examples of dispersants include alkyl sulphates, polyoxyethylene alkyl ether sulphates, polycarboxylic acids, alkylbenzene sorbates, reactive surfactants, fatty acids, naphthalen sulphonate formalin condensates and other anions. Sexual surfactants; cationic surfactants such as alkylamine salts, quaternary ammonium salts, amphoteric surfactants alkylbetaine, alkylamine oxides; polyoxyethylene alkyl ethers, polyoxyalkylene derivatives, sorbitan fatty acid esters , Polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene distyrene phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid castor oil, polyoxyethylene alkylamine, alkyl alkanolamide Nonionic surfactants such as. These dispersants may be used alone or in combination of two or more. The amount of the dispersant to be added is not particularly limited, but is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of water.

In the present embodiment, the glass wool mixture 1 is dispersed in a solvent 7 in which a dispersant is previously mixed with water, but the dispersant is mixed after the glass wool mixture 1 is dispersed in a water-only solvent. You may.

The reason why the dispersant is used in the S1 step is as follows. The new glass wool has relatively good wettability to water because the surface is free of dirt and the like. However, the glass wool contained in the glass wool mixture is subjected to a crushing treatment and a sorting process of a refrigerator, so that stains such as organic substances adhere to the surface of the glass wool and the wettability to water is lowered. Therefore, in order to improve the wettability of glass wool and water and allow water to permeate between the glass wool fibers, it is necessary to add a dispersant.

In the S2 step, the stirring propeller 10 was used as the stirring method, but another stirring method may be used. For example, a kneading mixer, an attritor, a stirrer stirrer, and the like can be mentioned. The purpose of stirring in the S2 step is to allow water to permeate into the bubbles (air layer) 6 inside the glass wool mass 5 contained in the glass wool mixture 1. Therefore, it is necessary to apply a shearing force to the glass wool mass 5. In order to apply a shearing force to the glass wool lumps 5, it is necessary for the glass wool lumps 5 to repeatedly collide with each other in the stirring step. Therefore, the solid content concentration of the glass wool mixture 1 in the S2 step needs to be adjusted to 3% by weight or more and 10% by weight or less. When the solid content concentration is less than 3% by weight, the frequency of collisions between the glass wool lumps 5 in the stirring step is significantly reduced. On the other hand, when the solid content concentration exceeds 10% by weight, the glass wool lumps 5 move in synchronization with the stirring in the stirring step due to the small amount of the solvent component, and the glass wool lumps 5 do not collide with each other.

If the glass wool fibers are stirred for an excessively long time while applying a shearing force, the glass wool fibers may be finely pulverized and it may take a long time to settle in water. Therefore, the stirring time is preferably 10 seconds or more and 10 minutes or less.

In the step S3, water is added to the dispersion to adjust the solid content concentration of the glass wool mixture 1 to 1% by weight or less for the following reasons. When the solid content concentration is less than 1% by weight, the amount of the solvent is smaller than the amount of the solid content, so that the interval between the floating urethane foam 4 and the precipitated glass wool 3 in the dispersion is shortened, and the glass wool 3 is separated. There is a high possibility that urethane foam 4 will be mixed in when only the solvent is separated and recovered. If the solid content concentration of the glass wool mixture 1 in the dilution step is too low, the amount of water to be added becomes larger than necessary. Therefore, the solid content concentration of the glass wool mixture 1 is preferably 0.3% by weight or more in practical use.

In the step S4, the container 9 is placed on the ultrasonic vibrator 11 as a method of applying the ultrasonic vibration, but another method may be used. For example, a method in which an ultrasonic generator is put into a container 9 containing a dispersion liquid 8 and ultrasonic waves are applied can be mentioned. Examples of the ultrasonic generator include an ultrasonic cleaner, an ultrasonic homogenizer, an ultrasonic defoamer, a throw-in type ultrasonic vibrator, an ultrasonic cleaning tank with a vibrator, and the like. The frequency of the ultrasonic wave is not particularly limited, and a frequency known in the art can be used. Examples of frequencies include the frequency domain from 25 kHz to 1000 kHz. Any one frequency in this frequency domain may be used, or a plurality of frequencies may be used. When a plurality of frequencies are used, a plurality of ultrasonic generators having different transmission frequencies may be used, or one ultrasonic generator whose frequency can be switched may be used.

The purpose of applying ultrasonic vibration in the S4 step is to separate the fine urethane foam 4 entwined with the glass wool lump 5 from the glass wool 3 by ultrasonic cavitation. The impact force due to cavitation is closely related to the frequency of ultrasonic waves, and generally, the lower the frequency, the stronger the impact force. Therefore, in order to efficiently separate the fine urethane entangled between the fibers of the glass wool mass, it is preferable to select a low frequency, and it is preferable to use a frequency of 25 kHz or more and 48 kHz or less.

As an example of the method of separating and recovering the glass wool 3 which is the sediment after the S5 step, there is the following method. For example, a method of scooping urethane foam floating near the water surface of the dispersion liquid with a net, a method of recovering the supernatant liquid containing urethane foam by decantation, and a method of adding more water to the dispersion liquid to make urethane foam Urethane foam is removed by a method such as overflowing the supernatant liquid containing the above from the container, and the settled glass wool is recovered.

The urethane foam and glass wool separated and recovered in this way are used as materials for reuse by the following steps. For example, when the recovered urethane foam is reused as a solid fuel, the recovered urethane foam is dried by evaporating water using a dryer or the like. When the recovered glass wool is reused as a non-woven fabric, the recovered glass wool is put into a wet papermaking process in a state of being dispersed in a dispersion liquid.

By applying the glass wool separation method configured in this way, the glass wool can be selected from the crushed material containing only the heat insulating material, and even foreign substances entangled between the fibers of the glass wool can be efficiently removed.

Next, a mock test for verifying the effect of the glass wool separation method according to the present embodiment will be described. As a glass wool mixture for the mock test, 25 g of urethane foam and 75 g of glass wool were prepared. The glass wool mixture that has undergone the actual crushing process contains urethane foam of various sizes, and contains coarse urethane foam that does not get entangled with the glass wool mass and fine foam urethane that easily gets entangled with the glass wool mass. Therefore, in order to simulate the glass wool mixture that has undergone the crushing step, the urethane foam is a mixture of 20 g of coarse urethane foam of ^{8 mm 3} or more and 5 g of fine urethane foam of less than ^{8 mm 3.} The glass wool was made by entwining single fibers having a fiber diameter of about 3 μm and a length of about 10 mm, and was made into an aggregate of cotton-like glass wool lumps every about 2 g. These urethane foam and glass wool were mixed using a mixer to obtain 100 g of a glass wool mixture for a mock test. In this glass wool mixture for the mock test, fine urethane foam is entangled between the fibers of the glass wool mass. In the following examples, S1 to S5 are shown together with the parts corresponding to the steps in the flowchart shown in FIG.

[Example 1]
Using a dispersant of a nonionic surfactant, 63.9 g of the above-mentioned glass wool mixture was dispersed in 1 liter (1,000 g) of a solvent containing 0.015% by weight of water as a main component. To prepare a dispersion (S1). At this time, the solid content concentration of the glass wool mixture is 6% by weight.

This dispersion was stirred for 3 minutes using a propeller stirrer (S2). Next, water was additionally added to the stirred dispersion and diluted so that the solid content concentration became 0.5% by weight (S3). Ultrasonic waves were applied to the diluted dispersion for 3 minutes using an ultrasonic cleaner (frequency: 48 kHz) (S4). Subsequently, the dispersion liquid after applying ultrasonic waves was allowed to stand for 5 minutes to separate the urethane foam floating near the water surface and the precipitated glass wool (S5).

Next, urethane floating near the surface of the water was removed by scooping it with a wire mesh, and glass wool was taken out from the remaining dispersion. The removed glass wool was dried in an oven at 120 ° C. for 5 hours, and the glass wool was collected.

[Example 2]
A dispersion was prepared by dispersing 31 g of the glass wool mixture in 1 liter of the solvent. At this time, the solid content concentration of the glass wool mixture is 3% by weight. In the subsequent steps, glass wool was recovered in the same manner as in Example 1.

[Example 3]
A dispersion was prepared by dispersing 111.2 g of a glass wool mixture with respect to 1 liter of the solvent. At this time, the solid content concentration of the glass wool mixture is 10% by weight. In the subsequent steps, glass wool was recovered in the same manner as in Example 1.

[Example 4]
In Example 1, the amount of additional water to be added was adjusted so that the solid content concentration when diluted was 0.3% by weight. Other than that, glass wool was collected in the same manner as in Example 1.

[Example 5]
In Example 1, the amount of additional water to be added was adjusted so that the solid content concentration when diluted was 1.0% by weight. Other than that, glass wool was collected in the same manner as in Example 1.

[Comparative Example 1]
A dispersion was prepared by dispersing 20.5 g of a glass wool mixture with respect to 1 liter of the solvent. At this time, the solid content concentration of the glass wool mixture is 2% by weight. In the subsequent steps, glass wool was recovered in the same manner as in Example 1.

[Comparative Example 2]
Glass wool was recovered in the same manner as in Example 1 except that the solvent was only water and no dispersant was added.

[Comparative Example 3]
Except that the dispersion was not agitated, glass wool was recovered in the same manner as in Example 1.

[Comparative Example 4]
Glass wool was recovered in the same manner as in Example 1 except that ultrasonic waves were not applied to the diluted dispersion.

[Comparative Example 5]
A dispersion was prepared by dispersing 136.5 g of the glass wool mixture with respect to 1 liter of the solvent. At this time, the solid content concentration of the glass wool mixture is 12% by weight. In the subsequent steps, glass wool was recovered in the same manner as in Example 1.

[Comparative Example 6]
Glass wool was recovered in the same manner as in Example 1 except that the solid content concentration of the diluted dispersion was 1.2% by weight.

The purity of the glass wool recovered in Examples 1 to 5 and Comparative Examples 1 to 6, respectively, was measured using the amount of weight loss due to heating described below.

The recovered glass wool was sufficiently dried and its mass was measured. The glass wool after the mass measurement was placed in an alumina crucible and heated at 500 ° C. for 3 hours using an electric furnace. The heated glass wool was taken out from the crucible, and the mass of the heated glass wool was measured. The purity (%) of the glass wool was determined from the weight ratio of the glass wool after heating to the weight of the glass wool before heating.

Urethane foam decomposes and burns at about 350 ° C. On the other hand, the melting point of glass wool is 800 ° C. or higher. Therefore, the urethane foam mixed in the recovered glass wool is completely burned down by heating at 500 ° C. for 3 hours, and only the glass wool is left after heating.

FIG. 5 is a list showing the characteristics of Examples and Comparative Examples in the glass wool separation method according to the present embodiment. In FIG. 5, the parameters of each Example and Comparative Example and the corresponding steps are shown together.

In FIG. 5, from Examples 1 to 5, Comparative Example 1 and Comparative Example 5, in S1, the solid content concentration in the dispersion liquid adjusting step needs to be 3% by weight or more and 10% by weight or less. Within this range, the purity of glass wool after separation and recovery is 95% or more.

When the solid content concentration is less than 3% by weight (Comparative Example 1), the frequency of collisions between glass wool lumps is significantly reduced in the stirring step of S2. On the other hand, when the solid content concentration exceeds 10% by weight (Comparative Example 5), the glass wool lumps move in synchronization with the stirring in the stirring step of S2 due to the small amount of the solvent component, and the glass wool lumps do not collide with each other. As a result, it becomes difficult to apply a shearing force to the glass wool mass in any of the comparative examples. As a result, a large amount of fine urethane foam remains in the recovered glass wool, and the purity of the recovered glass wool is lowered to 80% or less.

In Comparative Example 2, since the dispersant was not added to the solvent in the S1 step, water did not sufficiently permeate the inside of the glass wool mass, and fine urethane foam entangled between the fibers of the glass wool mass was present on the outside of the glass wool mass. The amount discharged is reduced. As a result, a large amount of fine urethane foam remains in the recovered glass wool, and the purity of the recovered glass wool is reduced to 56%.

In Comparative Example 3, since the stirring was not performed in the S2 step, the fine urethane foam entwined between the fibers of the glass wool mass is not discharged to the outside of the glass wool mass. In addition, water cannot sufficiently permeate the bubbles remaining between the fibers of the glass wool mass. As a result, fine urethane foam remains in the recovered glass wool, and the purity of the recovered glass wool is reduced to 53%. Further, since the bubbles remain in the glass wool lump, the apparent specific gravity of the glass wool lump becomes light and does not settle sufficiently, and a part of the glass wool may be removed as urethane foam in the S5 step. In this case, the purity of the urethane foam separated and recovered will decrease.

In Comparative Example 4, since ultrasonic waves were not applied in the S4 step, the fine urethane foam entwined between the fibers of the glass wool mass was not discharged to the outside of the glass wool mass. As a result, fine urethane foam remains in the recovered glass wool, and the purity of the recovered glass wool is reduced by 73%.

In Comparative Example 6, since the solid content concentration exceeds 1.0% by weight in the S3 step, the urethane foam separated from the glass wool and floated in the S5 step cannot be completely separated and recovered. As a result, unrecovered urethane foam is mixed and remains in the recovered glass wool, and the purity of the recovered glass wool is reduced by 76%.

From the above results, the method for separating glass wool in the present embodiment includes a stirring step of stirring a dispersion having a solid content concentration of 3% by weight or more and 10% by weight or less, and adding water to the stirred dispersion. A dilution step of reducing the solid content concentration to 1% by weight or less, a vibration step of applying ultrasonic vibration to the diluted dispersion, and a standing dispersion after the vibration step to separate suspended matter and sediment. It is necessary to have a separation process. By using the glass wool separation method configured in this way, the glass wool can be recovered with a purity of 95% or more.

1 Glass wool mixture, 2 Coarse urethane foam, 3 Glass wool, 4 Fine urethane foam, 5 Glass wool mass, 6 Bubbles (air layer), 7 Solvent, 8 Dispersion, 9 Containers, 10 Stirring propeller

Claims (2)

A method for separating glass wool from a mixture of glass wool and urethane foam , which is a method for separating the glass wool.
A dispersion in which the glass wool mixture is dispersed in a solvent containing water and a dispersant is prepared, and when the weight of the dispersion is 100% by weight, the solid content concentration of the glass wool mixture is 3% by weight or more and 10% by weight. The dispersion liquid adjustment process to be% or less, and
A stirring step of stirring the dispersion and
A dilution step of adding water to the stirred dispersion to bring the solid content concentration to 0.3% by weight or more and 1% by weight or less.
A vibration step of applying ultrasonic vibration to the diluted dispersion , and
A method for separating glass wool, which comprises a separation step of separating the suspended matter and the sediment by allowing the dispersion liquid to stand after the vibration step. The method for separating glass wool according to claim 1, wherein the glass wool mixture is obtained by simultaneously crushing a heat insulating material containing urethane foam as a main component and a heat insulating material containing glass wool as a main component.

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