KR100481043B1 - A fine-grained lightweight aggregate by use of the waste glass and the method for producing it - Google Patents

Abstract

The present invention relates to an artificial aggregate using waste glass, the aggregate of the present invention is based on solids 70-95% by weight of waste glass powder, 4-20% by weight foaming agent and 1-10% by weight of organic or inorganic binder as a molding aid It is very valuable in terms of environmental protection and recycling of resources because it is possible to manufacture fine-grained aggregates having a particle size of 1 mm or less as a raw artificial lightweight aggregate of foam-containing compositions, and to use waste glass and inorganic waste by-products as raw materials. And, through this, the use of such lightweight aggregates can be spread to many ships, if applied to military ships is expected to have a great effect.

Description

A fine-grained lightweight aggregate by use of the waste glass and the method for producing it}

The present invention relates to artificial aggregates, and more particularly, to a method for producing fine particulate artificial lightweight aggregates useful as structural materials for decks and high-rise buildings of ships using waste glass and inorganic waste by-products as raw materials.

Concrete is the most widely used material for construction and civil engineering. However, as concrete buildings are getting higher and larger in recent years, efforts have been made to reduce their weight.As a solution to this, many efforts have been made to lighten the aggregates that have the greatest influence on the specific gravity of concrete materials. have. In addition, it is becoming increasingly difficult to supply high-quality concrete aggregates in limited aggregate sources, and shortages of supply and demand for aggregates such as river sand and strong gravel collected from rivers are also appearing. Therefore, in order to solve these problems, interest in artificial lightweight aggregates is increasing, and in particular, many research and developments are being made on artificial lightweight aggregates. In other words, using such lightweight aggregate can be applied to the lightweight concrete (Lightweight Concrete) for structural use, thereby reducing the energy dependence and the dependence of the lack of natural aggregate through the increase of the building and the insulation performance of the building.

In addition, the deck of the ship should be finished with a certain thickness (about 7mm) of unsatisfactory parts such as welded parts. In the past, a thin coating was applied using a material such as polymer cement or polymer which is a nonflammable material. However, cement has a problem of reducing the total weight of the ship due to its high specific gravity, and in the case of polymers, it is not available due to the generation of toxic gas in the fire. Therefore, there is no problem in fire, it is possible to reduce the overall weight of the vessel, in consideration of improving the strength of the construction material it can be said that it is preferable to use a lightweight aggregate, which is an inorganic material in cement as a filler. However, existing lightweight aggregates are so large that they have problems to apply to ships.

Conventionally, artificial light weight aggregates include coal ash (domestic patent publication No. 95-8609), asbestos (domestic patent publication No. 81-123), waste plastic (domestic patent publication No. 80-1056), coal mine waste materials as raw materials. (Domestic Patent Publication No. 80-1054), Shale (Domestic Patent Publication No. 79-1985), Sedimentation of sedimentation basins (Domestic Patent Publication No. 73-166), Red Clay Clay (Domestic Patent Publication No. 71-242) It has been developed mainly for waste raw materials. Using these materials may be desirable in the method of recycling waste, but may not be suitable for the purposes of the present invention.

That is, in the above-mentioned majority of the patents, the weight of the aggregate is large and the waste of the raw material itself is used, so the specific gravity and the shape of the cell are also very heterogeneous. Therefore, these raw materials and methods can not control the particle size of the fine particles, even if the particle size is controlled, because of the very rough and large in the formation of the cell, there are many problems in the production of fine aggregate aggregates, there is a problem in strength even if manufactured Can be.

Therefore, the present invention, in view of all the problems of the prior art as described above, by finely controlling the granularity of the lightweight aggregate and the form of the cells formed therein, the composition of the lightweight aggregate of the fine aggregate different in use and form from the existing materials And to provide a method for producing a lightweight aggregate using the same as a technical problem.

According to the present invention that solved the above problems, the fine particles characterized in that the composition containing 70-95% by weight of the waste glass powder, 4-20% by weight of the blowing agent and 1-10% by weight of the molding aid based on the solid content The artificial light weight aggregate is provided.

In addition, the composition is based on 100 parts by weight of the total amount of waste glass powder, foaming agent and molding aid, the auxiliary additive 0- consisting of one or two or more mixtures selected from the group consisting of diatomaceous earth, fly ash and perlite powder It further comprises 40 parts by weight (solid content) and 0-20 parts by weight (solid content) of sodium hydroxide.

In addition, according to the present invention, by supplying the composition to the rotary kiln and primary molding at a temperature of 300-450 ° C to produce agglomerates, the aggregate is secondary molded at a temperature of 800 ℃ or more and 1100 ° C or less in the rotary kiln There is provided a method for producing particulate artificial light weight aggregate, characterized in that the foaming.

In addition, the method is characterized by recovering and releasing the releasing agent after the addition of the ceramic-based releasing agent sintered at a higher temperature than glass when secondary agglomerates.

Hereinafter, the present invention will be described in more detail.

Essential components in the composition of the artificial light weight aggregate of the present invention are waste glass powder, foaming agent and molding aid.

The waste glass powder is a pulverized product of waste glass such as discarded soda lime glass, borosilicate glass, aluminosilicate glass and the like, with the preferred content of essential components being 70-95% by weight, more preferably 80-90% by weight. If the content of the waste glass is less than 70% by weight, it is difficult to produce the desired lightweight aggregate and there is a fear that the strength is lowered. When it exceeds 95% by weight, it is difficult to control the specific gravity and is not suitable for use as a lightweight aggregate.

The content of the blowing agent in the essential component is preferably 5-20% by weight, more preferably 7-10% by weight based on solids, when the content is less than 5% by weight, the specific gravity may be excessively increased, 20% by weight If it exceeds%, the specific gravity may be excessively lowered and the strength may be lowered. Foaming of glass and ceramics heats the raw material mixed with a suitable blowing agent (which must be decomposed at the temperature at which the material softens) to soften and deform at the same time as the blowing agent is decomposed. However, in order to achieve a homogeneous and desired desired fabric size, the appropriate blowing agent and the appropriate glass are required. Any foaming agent can be used as long as it can decompose gas. However, in order to form a homogeneous foam, a cell of the desired form can be obtained only after the selection of a suitable foaming agent and many experiments.

A blowing agent can be used as long as it releases gaseous components while decomposing at a temperature at which the material softens. Examples of such blowing agents include liquid or solid calcium phosphate (CaO ₃ P ₂ O ₅ H ₂ O), calcium carbonate (CaCO ₃ ), carbon, sodium carbonate (Na ₂ CO ₃ ), iron oxide (Fe ₂ O ₃ ), antimony oxide ( Sb ₂ O ₅ ), arsenic oxide (As ₂ O ₅ ), or mixtures thereof. Particularly preferred blowing agents among them are calcium phosphate alone or a mixture of calcium phosphate and sodium carbonate, and calcium phosphate is more effective in the case of liquid than in the case of solid.

The foaming mechanism of some of the above blowing agents is as follows.

CaCO _3- > CaO + CO ₂ ↑

10CaO ₃ P ₂ O ₅ H ₂ O-> 10CaO ₃ P ₂ O ₅ + H ₂ O ↑

Dissolved SO _3- > S ₂ + CO ↑ + CO ₂ ↑ in carbon + glass

Carbon + As ₂ O _5- > As ₂ O ₃ + CO ₂ ↑

Carbon + Sb ₂ O _5- > Sb ₂ O ₃ + CO ₂ ↑

To obtain a homogeneous and desired size of the fabric, the appropriate blowing agent and the appropriate glass are required. Any foaming agent can be used as long as it can decompose the gas, but in order to form a homogeneous foam, it is necessary to select a suitable foaming agent and support many experiments to obtain a desired foam. In this respect, calcium phosphate is a very suitable blowing agent for producing lightweight aggregates having a suitable strength of less than 1 mm and closed holes. In the case of foaming agents such as carbon and calcium carbonate, the state of the fabric is good, but the shape of the cell is open, which is not preferable as a lightweight aggregate. In the case of Fe ₂ O ₃ , the cell wall is too thick, so the specific gravity is too large. Not preferred for use. In addition, in order to achieve the foaming according to the secondary molding at a lower temperature, it is preferable to use a blowing agent foamed at a low temperature, such as Na ₂ CO ₃ . 1 is an electron micrograph photographing the foaming state of the light weight aggregate obtained by different types of foaming agent, the carbon foaming agent is too large the size of the foam can be weak strength, in the case of CaCO ₃ is good As the shape of the cell is open, it is not suitable as a lightweight aggregate. In the case of Fe ₂ O ₃ , the cell wall is too thick, so the specific gravity is too large to be considered as a foaming agent alone, and the calcium phosphate foaming agent is lightweight. It has been shown to be the best as a blowing agent for aggregates. Figure 2 is an electron microscope photograph taken to increase the magnification to confirm the foam form using calcium phosphate, showing a small and homogeneous foam state. This shows the formation of a fine fabric of about 0.1-0.2mm, which can be controlled smaller by controlling the heat treatment temperature, and is considered to be a suitable foaming agent for producing lightweight aggregates having a suitable strength of less than 1mm and waste holes. .

In addition, the content of the molding aid in the above-mentioned essential components is preferably 1-10% by weight, more preferably 3.5-5% by weight on a solids basis. If the content of the molding aid is too low, the molding is difficult to break, and if the content of the molding aid is too high, self-aggregation and adhesion to the equipment occurs, making molding difficult. The molding aid is preferably an inorganic or organic binder, and examples thereof include an inorganic binder such as sodium silicate (water glass), an organic binder such as an aqueous PVA solution, an aqueous methyl cellulose solution, and the like.

In addition, the artificial light weight aggregate of the present invention may contain sodium hydroxide or an auxiliary additive as an optional component.

The solids content of sodium hydroxide in the optional ingredient is preferably 0-20 parts by weight, more preferably 4-10 parts by weight based on 100 parts by weight of the essential ingredient. Sodium hydroxide is to prevent the poor foaming and the rise of the secondary molding temperature, too high content may cause excessive foaming and strength decrease.

In addition, the solid content of the auxiliary additive in the optional ingredient of the present composition is preferably 0-40 parts by weight, more preferably 0-20 parts by weight based on 100 parts by weight of the essential ingredient. As such, when the auxiliary additive is blended, the strength of the final aggregate product can be effectively improved. Auxiliary additives can be reduced in specific gravity while increasing the strength, but since the bubble wall is thick, it is effective to use in the production of granules of 1 mm or more, and it is preferable not to add the granules of less than 1 mm. If the content of the coadditive is excessively large, the bubble wall may be excessively thick, resulting in poor foaming.

According to the present invention, it becomes possible to produce fine particulate aggregate of 1 mm or less. The interior of the lightweight aggregate made of particles of 1mm or less should be in a state made up of homogeneous cells made of a particle size of at least 0.1mm or less to maintain the strength as a lightweight aggregate.

Therefore, the present invention was able to maintain the strength of the aggregate by establishing a technology for forming fine cells of 0.1 mm or less in lightweight aggregates of 1 mm or less, and since glass is used as a raw material, the absorption rate is also low (absorption shows only absorption on the surface). It can be said that it has a good aspect as a lightweight aggregate.

In addition, the technique of forming the granules of 1mm or less in the molding can also be said to be the effect of the invention, in general, the lightweight aggregate is 5mm or more in size. This can be said that there is no big problem in the primary and secondary molding, but the molding of the present invention is light weight showing the particle size of less than 1mm in the secondary foam molding after mixing the state of the powder with the release agent visually in the primary molding Aggregate is made. Therefore, it can be said that the molding technology is different from the existing molding technology. In addition, the effect of the invention other than by reducing the temperature of the foaming by adding a suitable raw material to reduce the production cost, as well as recycling the waste resources by using waste glass.

In this production method, the soda-lime waste glass and the blowing agent, which are the main raw materials, are preferably mixed and pulverized and mixed into the rotary kiln before being introduced into the rotary kiln for primary molding. If desired, auxiliary additives may be mixed together when mixing waste glass and blowing agent.

Preferably, the finer the particle size of the glass powder added to the primary molding, the better the homogeneity of the primary molding and the fabric. The particle size of the preferred glass powder is about 200 mesh or less.

In addition, the primary molding is preferably molded while spraying the molding aid on the glass mixture powder under the operation of the rotary kiln. The primary molding is suitably carried out at a temperature at which the blowing agent does not decompose, preferably at a temperature of 300-450 ° C. If the primary molding temperature is too low, the cohesive strength is weak and the molding strength is low and can be easily broken. If the primary molding temperature is too high, secondary reactions (foaming) occur between components, making aggregate production impossible.

In this method, the molded article obtained by primary molding (spherical aggregate state) is secondary molded in a rotary kiln and foamed. Preferably, the temperature of the rotary kiln in the secondary molding is set to the temperature at which the glass softens and sinters. In particular, 800-1100 degreeC is suitable. At this secondary molding temperature, the glass softens and sinters, and at the same time, the blowing agent decomposes, releasing gas components, and the released gas forms fine cells in the sintered fine particles. If the temperature is too low at the time of secondary molding, the foaming is not properly made, the specific gravity is excessive and the production of lightweight aggregate is impossible, too high may be difficult to maintain the shape due to excessive liquid production, and may occur in the description. The foaming of glass and ceramic causes the foaming agent to decompose and soften at the softening temperature after being temporarily contracted when the raw material mixed with the appropriate blowing agent is heated to form a fabric.

In this secondary molding, the glass is sintered to allow the aggregates to adhere to each other. In order to prevent this, it is preferable to inject the ceramic-based mold release agent which is not sintered at the glass sintering temperature (approximately 1200 ° C.) together with the aggregate to perform secondary molding. These release agents are recovered and reused after molding. As such a ceramic mold release agent, you may use not only the zircon sand and kaolin used in the Example mentioned later but a low-cost general ceramic powder sintered at higher temperature than glass. For example, alumina powder, silica powder, etc. can also be used. The ceramic mold release agent is suitably added in an amount of preferably 0-40 parts by weight (solid content), more preferably 10-30 parts by weight (solid content) based on 100 parts by weight of the essential component of the present composition. In the second molding, if the release agent is not added or too little is added, coagulation of the composition and adhesion to the equipment may occur, and if the input amount is too large, there is no big problem, but the productivity of the aggregate may be reduced.

Although not particularly limited, the temperature control of the rotary kiln preferably has a temperature and temperature gradient of about three minutes, and it is preferable that the rotational speed of the rotary kiln can be adjusted.

In addition, the primary molding and the secondary molding may be performed in different rotary kilns, or in order to reduce process costs, the secondary molding may be performed after the primary molding in a single rotary kiln.

According to the present invention as described above by using the waste glass has a small particle size and a fine closed cell therein, the particle size of 0.25 ~ 2mm, the density (Bulk Density: Kg / dm 3 ± 10%) of 0.2 ~ 0.3 It is possible to produce fine particulate aggregate having a. Light weight aggregate of the present invention is a light weight aggregate that can be used for the deck of the ship (Deck), there is no problem in the fire, can reduce the overall weight of the ship, considering the strength of the construction material lightweight aggregate, which is an inorganic material in the cement Can be used as a filler.

Features and other advantages of the present invention as described above will become more apparent from the following examples. However, the present invention is not limited to the following examples.

Example 1

86.2 parts by weight of soda-lime waste glass and 8.6 parts by weight of liquid calcium phosphate foaming agent were added to a ball mill and ground at the same time as a solid to prepare a glass mixture having a particle size of 200 mesh or less. The obtained fine particle glass mixture was put into a rotary kiln, and the primary molding process was performed while spraying 5.2 parts by weight (based on solids) of water glass. At this time, the temperature of the rotary kiln was about 300 ~ 450 ℃. Next, 100 parts by weight of aggregates obtained in the primary molding process and 20 parts by weight of zircon sand as an auxiliary additive were supplied to other rotary kilns, and secondly molded at a rotary kiln temperature of 800-1000 ° C. to produce foamed lightweight aggregate.

3 is a photograph taken with an electron microscope of the foaming state according to the secondary molding temperature and time, Figure 3 (a) is 30 minutes at 900 ℃, Figure 3 (b) is 10 minutes at 950 ℃, Figure 3 ( c) is 20 minutes at 950 ℃, Figure 3 (d) is 30 minutes at 950 ℃, Figure 3 (e) is a picture of the foamed state of the aggregate obtained by secondary molding at 1000 ℃ 10 minutes. Homogeneous cell formation can be seen from the photographs at temperatures above 950 ° C.

[Examples 2-1 and 2-2]

In this example, since Example 1 is foamed at a relatively high temperature, it was tested using liquid sodium phosphate and sodium carbonate together as a blowing agent to lower the heat treatment temperature. Experimental conditions of Example 2-1 were the same as those of Example 1, except that 84.7 parts by weight of waste glass was added, 8.5 parts by weight of liquid calcium phosphate, 1.7 parts by weight of sodium carbonate, and 5.1 parts by weight of water glass were added as a blowing agent. In Example 2-2, 82.6 parts by weight of waste glass was added, except that 8.3 parts by weight of liquid calcium phosphate and 4.1 parts by weight of sodium carbonate were added as a blowing agent, and 5.0 parts by weight of water glass was added. Same as

Figure 2 is a photograph taken with an electron microscope of the foaming state according to the secondary molding temperature and time in Example 2-1, Figure 4 (a) at 900 ℃ 10 minutes, Figure 4 (b) at 900 ℃ The foaming state of the aggregate obtained by secondary molding for 20 minutes was photographed. From the photographs, it can be seen that the result of heat treatment at 900 ° C./20 minutes shows the best condition.

3 is a photograph taken with an electron microscope of the foaming state according to the secondary molding temperature and time in Example 2-2, Figure 5 (a) is 20 minutes at 800 ℃, Figure 5 (b) at 850 ℃ 10 (10), Figure 5 (c) is 20 minutes at 850 ℃, Figure 5 (d) is a picture of the foamed state of the aggregate obtained by secondary molding at 850 ℃ for 30 minutes. It can be seen from the above pictures that the specimens exhibited good condition in the specimens heat-treated at 800-850 ° C. lower than Example 2-1.

[Examples 3-1 and 3-2]

This example uses solid calcium phosphate to simplify the experimental process.

The experimental conditions of Example 3-1 were the same as those of Example 2-1 except that solid calcium phosphate was used instead of liquid calcium phosphate, and the experimental conditions of Example 3-2 were solid calcium phosphate instead of liquid calcium phosphate. Except that was used, it was the same as in Example 2-2.

In the case of Example 3-1, a poor foaming state was obtained. In the case of Example 3-2, the state of foaming with secondary molding temperature and time was analyzed by electron microscope, and liquid calcium phosphate was used. It was found to foam at higher temperatures, and because of the thicker walls, the foams exhibited better foaming conditions in the heat-treated specimens at lower temperatures of 800-850 ° C, but the homogeneity of the foams was lower than that of liquid calcium phosphate. (See FIG. 6 (a)-FIG. 6 (f)).

[Examples 4-1 and 4-2]

In this embodiment, diatomaceous earth was added to increase the strength of the lightweight aggregate.

In the experimental conditions of Example 4-1, 76.3 parts by weight of waste glass was added, 7.6 parts by weight of liquid calcium phosphate and 3.8 parts by weight of sodium carbonate were added as a blowing agent, 7.6 parts by weight of diatomaceous earth was added as an auxiliary additive, and 4.6 parts by weight of water glass. Except for the addition, it was the same as in Example 1, and in the case of Example 2-2, 70.9 parts by weight of waste glass was added, 7.1 parts by weight of liquid calcium phosphate and 3.5 parts by weight of sodium carbonate were added as a blowing agent. The same procedure as in Example 1 was repeated except that 14.2 parts by weight of diatomaceous earth and 4.3 parts by weight of water glass were added.

As a result of electron microscopic analysis, it was found that the shell wall was thicker than the case in which diatomaceous earth was not used. Particularly, in Example 4-1, when the heat treatment was performed at 850 ° C. for 30 minutes, the wall was suddenly thickened. 7 (a) to (c)]. In Example 4-2, in which the amount of diatomaceous earth was added, a thicker wall was formed than in Example 4-1.

As described above, the present invention is very valuable in terms of environmental protection and recycling of resources because it enables the production of fine light aggregates having a particle size of 1 mm or less and also uses waste glass and inorganic waste by-products as raw materials. The use of such lightweight aggregates can be spread on ships, and if applied to military ships, it can be said that it is a very useful invention that a great effect is expected.

1 is a photograph taken by electron microscopy of a sample prepared by using a variety of foaming agent fine lightweight aggregate using waste glass,

2 is an electron micrograph taken at a higher magnification of the sample using the liquid calcium phosphate blowing agent in FIG.

3 (a) to (e) are photographs taken with an electron microscope of the state of the sample according to the secondary molding temperature and time changes of Example 1,

4 (a) to (b) are photographs taken with an electron microscope of the state of the sample according to the secondary molding temperature and time change of Example 2-1,

5 (a) to (d) are photographs taken with an electron microscope of the state of the sample according to the secondary molding temperature and time change of Example 2-2,

6 (a) to (f) are photographs taken with an electron microscope of the state of the sample according to the secondary molding temperature and time change of Example 3-2,

7 (a) to (c) are photographs taken with an electron microscope of the state of the sample according to the secondary molding temperature and time change of Example 4-1.

8 is a photograph taken by electron microscope of the state of the sample according to the temperature and time changes at 850 ℃ the secondary molding in Example 4-2

Claims (4)

In artificial light weight aggregate, 70-95% by weight of waste glass powder based on solid content, 4-20% by weight as one or a mixture thereof selected from calcium phosphate, calcium carbonate and carbon as a blowing agent, and an organic or inorganic binder 1 as a molding aid. Fine artificial light weight aggregate using waste glass, characterized in that the foam containing the composition containing -10% by weight. The auxiliary additive according to claim 1, wherein the composition comprises one or two or more mixtures selected from the group consisting of diatomaceous earth, fly ash and perlite powder based on 100 parts by weight of essential components of waste glass powder, foaming agent and molding aid. Granulated artificial lightweight aggregate using waste glass, characterized in that it contains 0-40 parts by weight (solid content) and 0-20 parts by weight (solid content) of sodium hydroxide as optional ingredients. delete delete