JPS5860634A - Preparation of granular air-bubble glass - Google Patents

Abstract

PURPOSE:To obtain light granular air-bubble glass having improved heat insulating properties and high strength, by using limestone powder as a blowing agent to be blended with glass powder, granulating a mixture of the glass powder and the blowing agent, subjecting it to expansion treatment at high temperature. CONSTITUTION:A raw material obtained by blending glass powder with 1.0- 10.0wt% limestone powder as a blowing agent is granulated, and heated at 810- 960 deg.C to give granular air-bubble glass. When amount of the imestone is below the lower limit, the expansion is insufficient, and when it is above the upper limit, the limestone is reacted with the glass, crystallized, and the shape of the expansion is not kept with ease. Glass powder not crystallizing at 810-960 deg.C and having such a viscosity range as to cause the melting at least at the surfaces of the particles and causing sintering of the particles with each other is preferred. Any granulation method is applied, the granulation is preferably carried out with water glass, etc. and the diameters of the particles are preferably <= about 10mm. because of rapid heating and cooling. When the expansion temperature is below the lower limit, the porosity ratio of the product is low, and when it is above the upper limit, the viscosity of the glass is reduced excessively and a light weight product is not obtd.

Description

[Detailed description of the invention] The present invention relates to a method for producing granular foam glass.

Foam glass is a glass material with uniform, independent or continuous cells in the glass matrix, and is a useful industrial material due to its light weight, nonflammability, heat insulation, and heat-adding properties. Used as non-combustible insulation material. especially,
In recent years, it has been increasingly used for insulating walls and floors at extremely low temperatures due to its good thermal insulation properties and moisture absorption resistance at low temperatures.

Conventional foam glass manufacturing involves mixing glass powder with a foaming agent and placing it in a mold because of its hygroscopic nature. A method is adopted in which a molded product is formed by firing and foaming in a heating furnace, and then slowly cooled.

The biggest problem with this manufacturing method is the gradual cooling of the foam glass product after foam molding. Since the fired foam glass itself is an insulating material, it takes a long time to slowly cool it, and it is said that thicker glass requires annealing time of 24 hours or more. It requires formwork of
This also has the disadvantage that the manufacturing cost becomes very high.

” = The disadvantages noted above can be resolved by reducing the volume of the product being manufactured. That is, when the final product is shaped into small particles, there is no problem with slow cooling after foaming and no mold is required, so the manufacturing cost can be reduced. In addition, it can be used as an insulating material by simply making holes large enough to allow the granular foam glass to pass through the walls, floors, or ceilings of buildings that have already been constructed. It will spread further. moreover,
By making a composite material by mixing granular foam glass with cement etc. as an aggregate, it is possible to obtain a material that is lightweight and has excellent heat and sound insulation properties. Particularly in this case, when conventional lightweight aggregates such as perlite grains are mixed with mortar, the strength of the pearlite grains is insufficient, causing the grains to break, but granular foam glass has sufficient strength. can.

The purpose of the present invention is to provide a method for producing granular foam glass that is lightweight, has excellent heat insulation properties, and has high strength at a low cost. This is a method for producing granular foam glass, which is characterized by granulating raw materials blended at a ratio of 0.0% by weight and heating the granulated material at a temperature of 10°C to 20°C.

Limestone has the chemical formula caco3, and is produced in large quantities in Japan. Note that limestone may contain a small amount of dolomite, but this does not pose a problem for the present invention. Limestone varies depending on the production area, but it is mostly
The reaction begins with carbon, and the decomposition reaction rapidly increases at around 00°C.

That is, at temperatures above this temperature, the decomposition reaction occurs rapidly and is completed within a very short period of time. Additionally, limestone has a higher decomposition temperature than other carbonate ceramic raw materials, such as dolomite. This means that the raw material can be maintained without decomposition at higher temperatures, and therefore, by heating at high temperatures, the glass powder in the raw material can be sufficiently sintered before foaming begins. ,
Since no gas escapes in the unsintered state, the foaming efficiency is increased, and since the glass phase is sufficiently sintered, the strength can also be increased. In addition, limestone is cheaper than dolomite, and there are abundant sources of it.

If it exceeds it, it will react with the glass and crystallize, making it difficult to maintain the foamed shape. As a glassy powder, za10~q40'
Any composition may be used as long as there is no substantial crystallization in the heating temperature range of C, at least the surface portion of the glass powder particles melts, and the viscosity range is sufficient for sintering of the particles. .

Preferably, soda lime glass such as pin glass or plate glass is preferred in terms of cost and durability. Also glass powder,
The finer the particle size of limestone powder, the better.
It is preferable that S is thinner than 3 s mesh.

Regardless of the granulation method, from the viewpoint of the strength of the granular raw materials, in the case of room temperature granulation, it is preferable to add pineapple such as water glass. A granulation method that yields large particles is preferred. The diameter of the granulated particles is preferably 10 mm or less since heating and cooling are performed rapidly.

The reason why the heating temperature is limited to the above range is as follows.

In other words, at temperatures below 0'C, the decomposition reaction of limestone is slow, requiring a longer treatment time, and the sintering of the glass powder is also slow, allowing gas to escape from the gaps between the glass powder particles. The porosity of the product after foaming is reduced.

Furthermore, since the glass powders are not sufficiently sintered during treatment at such temperatures, the strength of the spherical foam glass produced at such temperatures is low. 9 g O'
If the glass powder exceeds C, the viscosity of the glass powder decreases too much and the generated gas cannot be trapped, resulting in a product that is not lightweight. In addition, since the granular raw material to be heated is relatively small, a short heating time is sufficient to reach the foaming temperature inside the glass, and on the other hand, heating for a long time will reduce the viscosity of the glass to the inside, so a heating time of 73 minutes or less is preferable. .

Examples using the manufacturing method of the present invention are shown below.

Example/ Ordinary architectural sheet glass powder as a vitreous powder.

Commercially available limestone powder was used as a blowing agent. After grinding both powders until they pass through a 100 Mesosie standard sieve,
A raw material powder was prepared by mixing 5% by weight of glass powder and 5% by weight of limestone powder in an alumina ball mill for 2 hours. This was granulated at room temperature using a pan-shaped granulator with a diameter of -o am. At that time, the pine heat sufficiently reaches the foaming temperature to the inside, and there is no need for slow cooling after foaming, and since the heating is for a short time, the inside temperature is maintained at a temperature convenient for foaming while the surface layer is heated. Since the foamed glass can be heated to a higher temperature and only the surface portion of the foamed glass can be made of glass without any pores, the foamed glass can have an extremely low water absorption rate.

Claims (2)

[Claims] (1) After granulating the raw material, which is a mixture of glass powder and 80-10.0% limestone powder by weight, 1r10-q40'C.
A method for producing granular foam glass, characterized by heating it at (2) The method according to claim 1, wherein the heating time is within 75 minutes.