KR100230179B1 - Manufacturing method of light-weight material using a clay - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for producing a porous defect building material based on clay.

2. The technical problem to be solved by the invention

The present invention has a uniform pore distribution by directly using low-grade natural clay, which is difficult to separate or remove particulate impurities, in the manufacture of lightweight building materials without undergoing separate purification process and has high compressive strength and excellent thermal insulation and light weight. An object of the present invention is to provide a method for producing a porous lightweight building material using clay.

3. Summary of Solution to Invention

The present invention for achieving the above object "70 to 90 parts by weight of primary firing in 10 to 60 minutes by heating up to 780 to 820 ℃ at a heating rate of 5 to 20 ℃ / min, feldspar 5 to 20 weight Part, and 5 to 10 parts by weight of alumina is mixed and pulverized to 30 µm or less, and then 20 to 30 parts by weight of water are added and stirred to form a suitable size, followed by drying sufficiently and again at 1200 ± 5 ° C for 28 to 32 minutes. It provides a method for producing a porous building material using clay of the method of "baking".

4. Important uses of the invention

The present invention has a use as a building material.

Description

Manufacturing method of lightweight building material using clay

The present invention relates to a method for producing a porous lightweight building material based on clay. More specifically, the present invention relates to a method for producing a porous lightweight building material using clay which can exhibit homogeneous pore size and excellent strength characteristics by preventing pore breakage due to rapid foaming of clay during firing.

In recent years, with the rapid increase in the construction of large buildings, the purpose is to reduce the self-load load of these building structures and to give them high functionality such as heat insulation and sound insulation. There is a growing interest in the method of using a lightweight building material, which gives porosity by firing ceramics with properties, as a building material such as aggregate, and research on this is being actively conducted.

In this regard, Japanese Special Raids No. 62-25620 or Specialty Nos. 62-24370 introduce a method for manufacturing artificial lightweight aggregates which are fired and foamed after the addition of shale powder using fly ash as a main raw material. 62-12186 discloses a method for producing a lightweight aggregate which is calcined in a state in which minerals such as rhyolite or petroleum are used as a main raw material, but a foaming agent and a pressure-sensitive adhesive are mixed, but the above description requires a very expensive organic solid agent. This causes not only a large increase in manufacturing costs, but also a difficulty in smooth supply and demand of fly ash, rhyolite or petroleum, etc., which are used as a raw material, which makes it difficult to mass-produce as a building material.

Separately, Korean Patent Publication No. 94-7221 provides a method for manufacturing a building material in which diatomaceous earth, bentonite or clay is mixed with other minerals such as pearlite and the like. By using clay that can be easily supplied, mass production as a building material is possible.

However, in the above technology, diatomaceous earth mixed as a blowing agent is sensitive to temperature, which may cause pore breakage at high temperature firing, and for this reason, the compressive strength of the manufactured fired body has an average compressive strength of 40 because it can only be fired at a relatively low temperature of 850 to 950 ° C. There is a problem of appearing as low as 45kg / ㎠.

In addition, since most of the used clays are low-grade natural clays buried in domestic mountains, pore breakage may occur due to rapid foaming at high temperature firing without separate separation and purification treatment. The phenomenon is particularly severe when the shale, dolomite, and the like, which are generally used as foaming aids, are fired together with clay, so that desirable results can be obtained in terms of physical properties such as heat insulation, light weight, and strength of the final product. There is no problem.

The present invention is to solve the above problems, it is possible to reduce the manufacturing cost by directly using low-grade natural clay difficult to separate or remove particulate impurities in the manufacturing of lightweight building materials without undergoing a separate separation and purification process In addition, the method of manufacturing a porous lightweight building material using clay, which can have a uniform pore distribution by preventing pore destruction by rapid expansion of the glass contained in the clay during high temperature firing, and can exhibit high compressive strength and excellent heat insulation and light weight. The purpose is to provide.

1 is a TGA-DTA curve measuring the hot change and the weight loss according to the heat treatment temperature of clay.

2 is a diagram showing a chemical composition of clay having good foamability at a high temperature firing of 1000 to 1300 ℃.

Figure 3 is an electron micrograph showing the pore state of the specimen prepared from Example 1.

Figure 4 is an electron micrograph showing the pore state of the specimen prepared from Example 2.

Figure 5 is an electron micrograph showing the pore state of the specimen prepared from Example 3.

Figure 6 is an electron micrograph showing the pore state of the specimen prepared from Comparative Example 1.

7 is an electron micrograph showing the pore state of the specimen prepared from Comparative Example 2.

8 is an electron micrograph showing the pore state of the specimen prepared from Comparative Example 3.

9 is an electron micrograph showing the pore state of the specimen prepared from Comparative Example 4.

The present invention for achieving the above object is heated to 780 to 820 ℃ at a temperature increase rate of 5 to 20 ℃ / min 70 to 90 parts by weight of clay first baked for 10 to 60 minutes, and feldspar 5 to 20 parts by weight Then, 5 to 10 parts by weight of alumina is mixed and pulverized to 30 μm or less, and then 20 to 30 parts by weight of water is added and stirred to form a suitable size, followed by drying sufficiently and again at 1200 ± 5 ° C. for 28 to 32 minutes. Provided is a method for producing a porous building material using clay of a firing method.

The clay in the natural state used in the present invention has a composition as shown in Table 1 below, although there are some differences depending on the extraction region.

As shown in Table 1, it can be seen that the natural clay used in the present invention has a large loss of ignition of about 11 wt%, which means that the excess moisture and organic matter contained in the clay at high temperature baking are H ₂ O and It is decomposed into gas such as CO ₂ .

As such, gases such as H ₂ O and CO ₂ generated when the clay is fired at a high temperature may expand the glassy film formed by melting SiO ₂ in the clay due to high temperature during firing, and thus may be lightened as porous as a foam core. Can be increased by rapidly heating the temperature at the time of firing to 1000 ° C. or higher to overlap the melt softening of clay and generation of gas.

However, since the clay is not subjected to separate purification process of organic matter and water, porous light weight construction having homogeneous pores due to breakage of pores due to rapid foaming and expandability by gas decomposition due to decomposition of these materials during firing. The manufacture of the material was not possible.

For this reason, in the present invention, by firing the clay at a temperature of 780 to 820 ° C before firing the clay at a temperature higher than 1000 ° C, it was possible to prevent rapid foaming at a later high temperature firing.

FIG. 1 shows that the clay calcined to natural temperature and 800 ° C in a differential thermal analyzer (Rigaku, PCT-10) using α-alumina as a standard sample was fired to 1200 ° C at a temperature increase rate of 10 ° C per minute. It shows TGA-DTA curve which measured the hot change and weight loss according to the heat treatment temperature at the time, and it is physically applied to the two types of clays at 80 ~ 150 ℃ on the DTA (Differential Thermal Analysis) curve. The endothermic peak was observed due to the desorption of adsorbed water, and the exothermic peak was observed due to the combustion of organic matter in the clay at 300 ~ 700 ° C. At 850 ° C., the exothermic peak was the transition of silica contained in the clay ( ? -Quartz to? -Quartz).

In addition, the weight loss of about 11wt% was observed in the range of 80 ~ 150 ℃ and 30 ~ 700 ℃ on the TGA (Thermal Gravity Analysis) curve due to the escape of adsorbed water and the combustion of organic matter in the thickening clay. This is consistent with the ignition loss measurement result of Table 1.

However, the clay calcined at 800 ± 20 ℃ was significantly reduced in exothermic peaks due to the burning of organic matters compared to the uncalcined coarse clay, and the weight loss of about 3wt% was shown on the TGA curve. In the case of clay, it was found that rapid foaming due to the organic combustion gas can be prevented even at high heating temperatures of 1000 ° C. or higher.

In general, Conley chemical composition of this preferred clay foamed at a high temperature sintering of 1000 to 1300 ℃ manufacturing lightweight aggregate According presented by the like (Conley) is Al ₂ on SiO _2, as shown in the diagram shown in FIG. 2 The ratio of O ₃ should be balanced, but the clay used in the present invention has an Al ₂ O ₃ : SiO ₂ ratio of 1: 4 and a relatively high composition ratio of SiO ₂ . In this invention, the glass is produced by increasing the ratio of Al ₂ O ₃ to SiO ₂ by adding alumina together with clay. Reduces the amount and viscosity of the melt and raises the melting point to suppress foaming by spilling the amount to the outside of the gas formed inside the specimen during heat treatment Kill number would by to get the pores of a uniform size, so that this case can not be obtained when the addition proportion of Al ₂ O ₃ added is less than 5 parts by weight to the mood 70 to 90 parts by weight of clay being preferred viscosity reducing effect 10 When added in excess of parts by weight, the viscosity decrease proceeds more than necessary, it is preferable to add 5 to 10 parts by weight because adversely affects the foamability due to the formation of open pores and breakage of the pores.

In the high temperature calcining treatment of alumina, feldspar and clay calcined primarily at 800 ° C. at a high temperature in the above-mentioned ratio, the higher the firing temperature and the firing time, the higher the glass melt is generated and the absorption rate of the calcined body is remarkably improved. Although it is effective, if the firing temperature exceeds 1200 ± 5 ℃ or the firing time exceeds 28 to 32 minutes, there is a problem that the glass melt is formed excessively, the pores formed by foaming are lost and thus the specific gravity is increased. It is preferable to bake for 28 to 32 minutes at a temperature of 1200 ± 5 ℃.

The feldspar used in the present invention is soda feldspar, which is embedded in a dark vein inside the granite having excellent whiteness and is present in the form of granular sand, which is mostly weathered by assembling or neutralizing, and its component is generally Na ₂ O 11.8wt%. , Al ₂ O ₃ 19.5wt%, SiO ₂ 68.7wt%.

When the feldspar is heated, it melts itself to form a glassy substance and remains in a glass state without crystallization even when cooled, and lowers the melting temperature of the material added together to promote a solid phase reaction generated during firing upon firing. It is preferable to add 5 parts by weight or more, but it is not necessary to add 20 parts by weight or more.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Experimental Examples.

Example 1

Clay collected from Jeongwon-gun, Gangwon-do, charged into a tubular furnace with an inner diameter of 60 mm and a length of 400 mm, and then heated to 800 ° C. at a heating rate of 10 ° C./min, and maintained for 30 minutes. Then, 500 g of Anyang feldspar and 500 g of alumina were mixed and ground to an average particle size of 30 μm or less using a ball mill grinder.

Subsequently, 2.5 liters of water was added thereto, and the mixture was sufficiently stirred to form a 15 mm spherical specimen at room temperature for 7 days, followed by drying at 110 ° C. for 72 hours using a drying oven.

The specimen thus prepared was charged into a tubular furnace heated at 1200 ° C., and then calcined for 30 minutes to prepare a porous building material of the present invention.

Example 2

In the same manner as in Example 1, the amount of primary calcined clay was 8 kg and the amount of anyang feldspar and alumina was 1 kg, respectively.

Example 3

In the same manner as in Example 1, the amount of primary calcined clay was 7 kg, the amount of anyang feldspar was 2 kg, and the amount of alumina was 1 kg.

Comparative Example 1

In the same manner as in Example 1, but using a natural clay 10kg omission of the first calcination process at 800 ℃ was not added yangyang feldspar and alumina.

Comparative Example 2

In the same manner as in Example 1, 3 kg of shale was added in place of natural clay 7 kg, anyang feldspar, and alumina, which omitted the first step of calcination at 800 ° C.

Comparative Example 3

In the same manner as in Example 1, 3 kg of dolomite sludge was added in place of 7 kg of natural clay and anyang feldspar and alumina, which omitted the process of calcination first at 800 ° C.

[Comparative Example 4]

In the same manner as in Example 3, as the clay used was used a natural clay that was omitted the process of calcination first at 800 ℃.

Experimental Example

Using the specimens prepared in Examples 1 to 3 and Comparative Examples 1 to 4, the specific gravity was measured by the method according to KSL 3304, the absorption rate was measured by the method according to KSF 2533, and the compressive strength by the method according to KSL 3305. Was measured and the results are shown in Table 2 below.

In addition, the cross-sections of the specimens prepared from Examples 1 to 3 and Comparative Examples 1 to 4 were observed by electron microscopy to observe the formation of pores, and the results are shown in FIGS. 3 to 9, respectively.

As shown in Table 1, in the case of Examples 1 to 3 of the present invention using the clay, alumina and feldspar firstly calcined at 800 ° C., compared to Comparative Examples 1 to 4 using clay, which omitted the primary calcining process In general, it shows very excellent properties in strength, especially when compared with Comparative Examples 2 to 3 using shale or dolomite which is used as a conventional blowing agent as a material added with clay, and is significantly higher by about 46.1% to 50.7%. It can be seen that the improved strength characteristics are shown, and the overall weight is very good light weight as the specific gravity or 0.83g / ㎝ or less. In addition, the absorption rate was 1.5% or less, showing excellent resistance to freeze-thawing or very good.

3 to 5 are cross-sectional images of specimens prepared in Examples 1 to 3 of the present invention by electron microscopy. The pores are homogeneous and the pores destroyed by rapid foaming cannot be observed. In addition, it can be seen that excellent results can be obtained in thermal insulation, but in the case of specimens prepared from Comparative Examples 1 to 4 shown in FIGS. 6 to 9, the pore sizes are not homogeneous as a whole, and the interface of the pores is destroyed. There were many parts.

Compared with Comparative Examples 1 to 4 in the above table, Examples 1 to 3 of the present invention showed relatively poor results in volume specific gravity and water absorption. This is a comparative example of the glassy melt contained in clay during high temperature firing. Due to the increase in the amount of increase in glass nitriding on the surface of the specimen, the absorption rate is slightly lower, and also the volume specific gravity is also lowered as the pores formed by the rapid foaming during firing and the size thereof are irregularly enlarged.

The present invention has a uniform pore distribution by directly using low-grade natural clay, which is difficult to separate or remove particulate impurities, in the manufacture of lightweight building materials without undergoing separate purification process and has high compressive strength and excellent thermal insulation and light weight. It is a useful invention to provide a method for producing a porous lightweight building material using clay.

Claims (1)

70 to 90 parts by weight of clay, firstly calcined for 10 to 60 minutes, 5 to 20 parts by weight of feldspar, and 5 to 10 parts by weight of alumina were heated to 780 to 820 ° C. at a heating rate of 5 to 20 ° C./min. After pulverizing to 30 ㎛ or less and added to 20 to 30 parts by weight of water and stirred to form a suitable size, then dried sufficiently and then secondly baked at 1200 ± 5 ℃ 28 to 32 minutes, characterized in that porous Method of manufacturing building materials.

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