JPH0143695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glass powder from glass fiber waste.

Glass fiber spinning and winding process, glass fiber fabric,
Glass fiber waste is generated from many glass fiber manufacturing processes, such as the manufacturing process of sleeves, as well as the manufacturing process of chopped strands or mats as substrates for reinforced plastics.

Generally, the glass fiber waste generated in the above manufacturing and processing steps is roughly classified into the following two types.

(1) Relatively thick debris generated during the process of turning glass into fibers, ranging in size from approximately 20μ to several hundred μ.

These are generated during the formation of glass fibers, have little organic matter attached to them, are relatively small in bulk, and are thick and brittle, making them easy to crush.
It is possible to reuse it by grinding it into pieces smaller than mm and returning it to the glass melting furnace after removing the moisture.

It is common knowledge that bottle glass manufacturers etc. crush glass waste and reuse it as a raw material, but this waste can be easily reused just like bottle glass waste and does not pose any particular problem.

(2) Scraps of sufficiently fine fibers, usually 3~
These include 17μ filaments, strands that are aggregates of filaments, chopped strands processed from these, mats, glass cloth, etc.

These products are sized with starch or similar substances, or plastic-based organic substances, and the above sizing agents also contain many softening and smoothing agents, so they are often flexible. .

Therefore, it is generally difficult to cut or crush it into small pieces for easy handling, and even if it is cut, it is difficult to reuse it as a raw material because the sizing agent is still attached, and in many cases It had been discarded.

The present invention relates to a method of processing and reusing the latter fiber waste, which is difficult to recycle, using relatively inexpensive equipment.

This glass fiber waste is characterized by being bulky and also comes in various shapes.

In the present invention, first, this bulky glass fiber waste is compressed as necessary, or without compression, and then fired for 10 to 20 minutes at a temperature gradient of about 350°C at the inlet and about 800°C at the outlet. Pass through the furnace on a conveyor belt. Through this firing process, the sizing agent is completely burned out, and the glass fiber waste becomes brittle and stiff, and is crushed by a crusher.
Easily crushed into ~5cm chips. The glass fiber waste thus chipped is easily ground into powder of 200 mesh or less using, for example, a vibration mill.

Although the above-mentioned continuous processing method is preferable in terms of high processing efficiency, it goes without saying that the batch method can also be used.

The reason why the glass fiber waste is compressed here is to reduce the bulk and at the same time to equalize the density and eliminate uneven firing. However, compression is not an essential condition, and in some cases, such as with pine waste, bulkier materials may prevent uneven burning. This is probably because chopped strand pine waste has about 5% of organic matter attached to it and therefore requires a large amount of oxygen, so it would be better to leave it bulky to avoid uneven firing.

The reason why the inlet temperature of the kiln was set at approximately 350°C is because if the glass fiber waste was suddenly heated to high temperatures of 700°C or 800°C, the sizing agent would carbonize, making it impossible to reuse it as a raw material for glass. On the contrary, about
If the temperature is below 350°C, the sizing agent has the disadvantage of being difficult to burn completely.

The reason for keeping the temperature at the exit of the firing furnace to approximately 800°C is approximately
This is because glass fiber waste softens and becomes lumpy at high temperatures of 800°C or higher. On the other hand, if the temperature is lower than about 800°C, a disadvantage arises in that it takes a long time for the glass fiber debris to become brittle.

In addition, the time taken to pass through the firing furnace was set to 10 to 20 minutes.
If the sizing agent is passed through at high speed for less than 1 minute, it will enter the high temperature region before it is completely combusted and carbide will be generated.
Also, since the glass fiber waste is not treated at a sufficiently high temperature, it suffers from insufficient embrittlement, and on the other hand, if it is allowed to pass slowly for more than 20 minutes, the glass fiber waste softens and becomes lumpy.

Hereinafter, the present invention will be specifically described with reference to Examples.

In the attached drawing, various glass fiber scraps 1 mixed with cake scraps, chopped strand selvage scraps, leftover yarn scraps, etc. are placed on a belt conveyor 3 that is carried into a firing furnace 2 to eliminate uneven firing. It is compressed by the compression conveyor 4 so that the inlet temperature is
It was heated by passing through a firing furnace 2 having a temperature gradient of 400°C and an outlet temperature of 800°C for 15 minutes. By compressing, the organic matter adhering to the glass fiber waste generates internal heat and self-combusts, accelerating firing, and the glass fiber waste is sufficiently embrittled without carbonization in 15 minutes. I was disappointed.

This fired and embrittled glass fiber waste is then fed into the crusher 5, where it is heated for 3 minutes and 1 hour.
Shredded into ~5cm chips. The chipped fiber waste 6 was fed into a vibrating mill 8 using a screw feeder 7, where it could be ground into powder of 200 mesh or less in 10 seconds.

The glass powder thus treated was very easy to handle, and even when mixed with glass raw materials (referred to as batches), there was no adverse effect on operation or glass quality.

Note that 9 is a heat exhaust facility, and this heat is reused.

For comparison, glass fiber waste that was not subjected to the above-mentioned firing process was crushed using a crusher.
It takes 12 minutes to crush into chips of 1 to 5 cm.
It takes four times as long as the present invention, and it takes 200
It takes 100 seconds to grind to a powder of less than mesh size,
It took 10 times longer than the present invention, and since the sizing agent remained attached, it was not possible to mix it with the glass raw material and reuse it as it was.

The present invention can easily pulverize glass fiber waste using relatively simple equipment as described above, and therefore has great economic effects in addition to resource and energy saving effects.

[Brief explanation of drawings]

The accompanying drawings are schematic explanatory diagrams of an apparatus for carrying out the method of the invention.

Claims (1)

[Claims] 1 Before crushing the glass fiber waste with a crusher and powdering it with a mill, the glass fiber waste is heated from about 350℃ to about 800℃.
A method for producing glass powder, which comprises heating for 10 to 20 minutes in a heating furnace that gradually raises the temperature to ℃.