JPS5964564A - Manufacture of natural glass foam bead - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing foamed natural glass particles with excellent foamability.1 Generally, expandable natural glasses such as obsidian, nacre, rosinite, and shirasu are heated to 800 to 1300°C. This is known to result in foaming and expansion.

Conventionally, foaming was carried out by placing the material in an atmosphere maintained at 800 to 1300° C., but the foaming ratio (volume of foamed particles after foaming/volume of raw stone before foaming) was about 20 times.

For example, even obsidian, which is said to have relatively high foaming properties, has a
When heated and foamed at 00°C, the foaming ratio is 20 to 3.
It is 0 times.

The present invention has been made in view of the above, and its purpose is to improve the foamability of natural glass particles and to provide a method for producing expanded particles suitable for use as a heat-insulating lightweight aggregate and the like.

As a result of studies on the foamability of natural glass particles, the present inventors have discovered that high foamability can be achieved using a new manufacturing method, and have completed the present invention.

That is, in the present invention, when producing foamed beads by heating and foaming foamable natural glass grains, in advance.

This is a method for producing foamed natural glass beads, which is characterized in that natural glass beads are treated with steam at a temperature of 600 to 900°C, and then heated and foamed.

According to this manufacturing method, foamed granules exhibiting a high expansion ratio that could not be obtained by conventional manufacturing methods can be obtained. for example.

The foaming ratio can be improved by 501 points or more compared to the conventional foaming ratio1, and if a foaming ratio comparable to that of the conventional foaming ratio is to be obtained, it is possible to lower the temperature or shorten the time for heating and foaming.

The reason for the improved perspiration properties is that the water vapor treatment at high temperatures changes the water content on the surface of the raw stone, causing a change in viscosity when melted.

Alternatively, it is thought that the internal stress of the natural glass is relaxed and stress concentration is avoided.

The natural glass grains of the present invention include obsidian, perlite, rosinite, whitebait, etc., and especially when black stone grains are used as a raw material, the effect is remarkable.

What is particularly important in the present invention is the steam treatment conditions.
>ru. That is, the temperature conditions in the steam treatment of the present invention are limited to 6006C to 900C. At temperatures below 600°C, the improvement in foamability is small compared to conventional foaming properties, and no great effect can be expected; at temperatures above 900°C, a large proportion of the raw ore already begins to foam, resulting in a difference in the yield of treated raw ore. The temperature is preferably 700°C to 850'C. In addition, the processing time is determined by the processing method and water vapor pressure, but usually 5 minutes to 1
It is 50 minutes. If the time is less than 5 minutes, sufficient foaming properties cannot be expected.
Even though it takes a long time and a lot of time for 150 minutes or more, the foaming property is low.

More preferably, the time is 10 to 90 minutes.

In carrying out the steam treatment of the present invention, the effects of the present invention can be exhibited by injecting the steam into a high-temperature rotary kiln or tunnel furnace. Naturally, steam treatment is not limited to these facilities.

The present invention will be explained below with reference to Examples and Comparative Examples.

(Example 1) Particle size 3.0-4. Crushed to Ottrm, sifted, fc Kurokuroishi stone grains approximately 200? 'i Stainless steel box (200 mm (length) x
The box was placed in a Matsufuru furnace whose temperature had already been raised to 750° C., and steam was passed through the steam inlet and discharge pipe. After processing in that state for 90 minutes, take out the rough stones in the box, and place the extracted rough stones in another Matsufuru furnace for 1ooo
When heated and foamed at 'c' for 5 minutes, the foaming ratio of the foamed beads obtained was approximately 42 times.

(Example 2) Kuroishi stone grains crushed and sieved to a particle size of 4.5 to 5.5 mm were fed into a horizontal rotary kiln that was continuously supplied with steam and maintained at 800°C. After processing for 30 minutes, the raw stone taken out was heated and foamed at 1000° C. for 5 minutes, resulting in expanded beads with a 5 expansion ratio of about 50 times.

(Comparative Example 1) The same Kuroishi stone grains as in Example 1 were put into a Matsufuru furnace that had already been heated to 1000°C, using the conventional manufacturing method, and
Heating for a minute? As a result, the foaming ratio of the foam particles obtained was approximately 22 times.

(Comparative Example 2) Using the same raw stone and processing equipment as in Example 2, a material treated at 550°C for 100 minutes only in the temperature section was heated and foamed at 1000°C for 5 minutes, resulting in an expansion ratio Q of approximately 25. It was double that.

(Comparative Example 3) After processing using the same raw stone, treatment equipment, and temperature condition Y as in Example 1, only for a treatment time of 200 minutes, the extruded raw stone was heated and foamed at 1000° C. for 5 minutes. The expansion ratio of the obtained expanded beads was approximately 28 times.

As described above, the present invention enhances the foamability of natural glass particles,
It is possible to obtain foamed granules with a low bulk density that cannot be obtained using conventional manufacturing methods, and even when used in U: heat-insulating lightweight aggregate, etc., it is possible to obtain foamed granules that are thick and have excellent value at first glance. can do.

Patent applicant Asahi Kasei? Ita, ceremony company

Claims (1)

[Claims] A method for producing foamed natural glass granules, which comprises heating and foaming expandable natural glass granules to produce foamed granules.