KR20140013268A - Fabrication of artificial light-weight aggregates of uniform bloating properties using a temperature-raising sintering method - Google Patents

Abstract

Disclosed are a manufacturing method of artificial light-weight aggregates which have an uniformed foaming property of the inside of the aggregates, and artificial light-weight aggregates by using a material which comprises reject ash by controlling the inserting temperature, heating speed, sintering temperature, and having low specific gravity and absorptance without adding separate blowing agent, fusing agent. The present invention relates to a manufacturing method of artificial light-weight aggregates by using a material which comprises reject ash and temperature elevation sintering method which comprises: (a) a step of inserting a material to a preheated firing furnace; (b) a step of elevating the temperature of the furnace in which the material is inserted; (c) a step of maintaining in the optimum elevated temperature after finishing the elevation of the temperature; (d) discharging the material which is finished sintering after maintaining for a predetermined time. [Reference numerals] (AA) Embodiment 1-4; (BB) Embodiment 5-8; (CC) Embodiment 9-12; (DD) Comparison example 1-4

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an artificial lightweight aggregate having a uniform foaming property by a heating-

The present invention relates to an artificial lightweight aggregate, and more particularly, to an artificial lightweight aggregate having lightweight, structural uniformity and low water absorption using a backbone which is required to be recycled, and a manufacturing method thereof.

The present invention was derived from research carried out as part of a project supported by the Korea Science and Engineering Foundation in 2009.

[Project Assignment Number: 2009-0077077, Title of Study: Basic research among general researchers]

Korea's thermal power plant uses 37.78 million tons of imported coal per year and produces 37% of the electricity used in Korea. In this process, 8.35 million tons of fly ash is generated annually. Fly ash is divided into fly ash and bottom ash according to the characteristics, with 6.4 million tons of fly ash per year and 1.51 million tons of bottom ash. Fly ash is called "reject ash" because it has a small particle size and excellent composition and is mostly recycled. However, it is not recycled because it has a large carbon content and large particle size.

On the other hand, it is generally known that in order to produce a lightweight ceramic aggregate having a specific gravity of 1.0 or less, suitable bubble forming and liquid phase generating components must be present in the raw material (Non-Patent Document 1). In addition, it is common to use direct flame-directing method in which the furnace is directly heated to a furnace heated to a firing temperature. The cross-sectional structure of the aggregate produced therefrom includes a so-called black core in black, A typical pattern consists of a shell of color. However, there is a problem that the pore size in the black core is different from that of the pores existing in the shell, and the pore size distribution is not uniform in the entire specimen (Non-Patent Documents 1 to 4).

A prior art disclosed to date on the production of a lightweight aggregate using such fly ash or soda ash has been disclosed in Japanese Patent Laid-Open No. 1998-0033800, which discloses the production of a lightweight aggregate by mixing and firing fly ash, However, there is a problem in that the pore size distribution of the aggregate is not uniform using the above-mentioned direct method, and no mention is made as to use of the lightweight aggregate as a raw material.

Open Patent Application No. 2011-0109706 discloses the use of the artificial lightweight aggregate containing fly ash, but also uses a direct method to form a black core inside the aggregate, There is one problem.

In addition, in Patent Publication No. 0886801, there is disclosed the production of a cement composition utilizing a residual society, but the introduction of a simple application method as a building material of the underground society and the use of a foamed lightweight aggregate are not mentioned .

As described above, although recycling of the solids is particularly demanded, even when additional foaming agent or flux is added to the artificial lightweight aggregate by using the solids so far, due to the limitation of the manufacturing method, unevenness of the pores in the aggregate , And it has been difficult to develop an artificial lightweight aggregate having lightweight properties in terms of specific gravity and water absorption.

[Non-Patent Document]

Non-Patent Document 1: C. R. Austin et al., "Basic Factors Involved in Bloating of Clays ", Am. Ins. Min. and Metal. Eng., Technical Publication, 1486, 1-11 (1942)

Non-Patent Document 2: K. D. Kim, "A Study on Application and Fabrication of Functional Ceramics for Constructing Materials using Ecofriendly Waste Recycling Process ", pp.25-35, Ph. D. Thesis, Kyonggi University, Suwon, 2010

Non-Patent Document 3: W. E. Brownell, "Black Coring in Structural Clay Products ", J. Am. Ceram. Soc., 40 [6] 179-87 (1957)

Non-Patent Document 4: C. M. Riley, "Relation of Chemical Properties to the Bloating of Clays ", J. Am. Ceram. Coc., 34 [4] 121-28 (1951)

Accordingly, the present invention relates to a method for producing an artificial lightweight aggregate using a material made of a glass material, which has a low specific gravity and a low water absorption rate without adding a foaming agent, a flux, etc. by controlling the injection temperature, the heating rate, The present invention relates to an artificial lightweight aggregate and a method of manufacturing the same, and more particularly, to provide an artificial lightweight aggregate having a uniform foaming property inside the aggregate and a manufacturing method thereof.

According to an aspect of the present invention, there is provided a method for manufacturing an artificial lightweight aggregate using a material made of reject ash, the method comprising the steps of: (a) introducing the material into a preheated firing furnace; (b) heating the fired furnace into which the material is introduced; (c) maintaining the temperature at a final temperature elevation temperature after the completion of the heating; And (d) discharging the sintered material from the sintering furnace after the sintering is completed for a predetermined period of time. The present invention also provides a method for manufacturing an artificial lightweight aggregate using the sintering method.

The method for manufacturing an artificial lightweight aggregate using the elevated temperature firing method is characterized in that the preheating temperature in the step (a) is 800 to 1000 ° C.

The method of manufacturing an artificial lightweight aggregate using the elevated temperature firing method is characterized in that the step (b) is performed at a heating rate of 1 to 30 ° C / min.

Also, the method of manufacturing an artificial lightweight aggregate using the elevated temperature firing method is characterized in that the temperature rise in the step (b) is performed at a heating rate of 5 to 20 ° C / min.

Also, the method of manufacturing an artificial lightweight aggregate using the elevated temperature firing method is characterized in that the temperature rise in the step (b) is performed at a heating rate of 10 to 15 ° C / min.

The final temperature elevation temperature of step (c) is 1200 to 1300 ° C. The method of manufacturing artificial lightweight aggregate using the elevated temperature firing method is provided.

In addition, the present invention provides a method for manufacturing an artificial lightweight aggregate using the elevated temperature firing method, wherein the final temperature elevation temperature in the step (c) is 1250 to 1275 ° C.

Also, the present invention provides a method for manufacturing an artificial lightweight aggregate using the elevated temperature firing method, wherein the predetermined time of the step (c) is 1 to 30 minutes.

Also, the present invention provides a method for manufacturing an artificial lightweight aggregate using the elevated temperature firing method, wherein the predetermined time of the step (c) is 5 to 15 minutes.

The present invention also relates to an artificial lightweight aggregate formed by heating and firing a material made of reject ash, wherein the iron oxide component present in the interior of the artificial lightweight aggregate is reduced And the inner surface is not present in the adjacent portion of the outermost surface of the artificial lightweight aggregate, and the whole interior is oxidized and foamed.

Also, the artificial lightweight aggregate has a specific gravity (KS F 2503) of 1.0 to 1.5.

Also, the artificial lightweight aggregate has a specific gravity (KS F 2503) of 1.0 to 1.2.

Also, the artificial lightweight aggregate has a water absorption rate (KS F 2503) of 0 to 18%.

Also, the artificial lightweight aggregate has a water absorption rate (KS F 2503) of 0 to 1%.

According to the present invention, by forming the artificial lightweight aggregate by heating and firing a material composed of a glass body, the lightweight aggregate formed by the conventional direct firing method without the addition of any foaming agent or flux, It is possible to provide an artificial lightweight aggregate having excellent lightweight characteristics showing water absorption.

In addition, by providing a lightweight aggregate exhibiting excellent lightweightness and structural uniformity by using the reusable societies, it can be utilized in various applications such as lightweight concrete, contaminated soil, bio-carrier for water purification, and smart light aggregate .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing components constituting a residual solid which can be used in the present invention,
2 is a graph showing specific gravity measurement results of the artificial lightweight aggregate produced according to Examples 1 to 12 and Comparative Examples 1 to 4 according to the temperature raising rate and the final heating temperature,
FIG. 3 is a graph showing the water absorption rate measurement results of the artificial lightweight aggregate produced according to Examples 1 to 12 and Comparative Examples 1 to 4 according to the heating rate and the final heating temperature,
4 is a graph showing the results of measuring the specific gravity of the artificial lightweight aggregate produced according to Examples 9 to 20 according to the preheating temperature of the present invention,
FIG. 5 is a graph showing the water absorption rate measurement results of the artificial lightweight aggregate produced according to Examples 9 to 20 of the present invention according to the preheating temperature. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Also, throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The inventors of the present invention have found that when producing artificial lightweight aggregate using a material made from a coarse material, foaming agent, flux and the like are added to the coal fly ash in the prior art and the foaming characteristics are uneven in the firing by the direct firing method, Unlike the direct method, by adopting a series of elevated temperature firing method through specific injection temperature, heating rate and firing temperature, it is found that the problem can be drastically improved only by the material consisting essentially of the residual sphere without adding any additives. It came to the invention. Hereinafter, the process for producing the artificial lightweight aggregate using the elevated temperature firing method according to the present invention will be described in detail.

The present invention relates to an artificial lightweight aggregate formed by heating and firing a material composed of a residual sphere, wherein an iron oxide component present in the interior of the artificial lightweight aggregate is not reduced, A lightweight aggregate of artificial lightweight aggregate which is free from an internal interface and which is oxidized and foamed in its entirety, wherein the artificial lightweight aggregate is made of a material consisting of (a) injecting the material into a preheated firing furnace; (b) heating the fired furnace into which the material is introduced; (c) maintaining the temperature at a final temperature elevation temperature after the completion of the heating; And (d) discharging the baked material from the baking furnace after the baking for a predetermined period of time.

Firstly, coal residues used in the present invention can be coal reject ash, for example, those originating from a domestic 'Y' thermal power plant. Table 1 shows the results of XRF (ZSX-100e, Rigaku, Japan) analysis of an example of the chemical composition of the solids used in the present invention. As shown in Table 1, the composition oxides can be divided into a frame oxide, a neutral oxide, and a fluxing oxide, which form a frame based on a conventional ceramic classification method. The acidic oxide is a non-metal oxide belonging to the RO ₂ group and is representative of SiO _{2. The} neutral oxide is an amphoteric element oxide belonging to the R ₂ O ₃ group and Al ₂ O ₃ is a typical oxide. Also, the flux oxide belongs to RO or R ₂ O group as a group 1 or group 2 metal oxide. These acidic oxides, neutral oxides and fluxes form a ceramic three-component system.

FIG. 1 is an explanatory view showing a ceramic three-component graph according to the present invention. FIG. Degrees (shown as "SiO _2") in the first structure (acid) oxide, were the sum of the neutral oxide (indicated by _{"Flux") ( "Al 2} O 3" shown as) and flux oxides to '100', and other The oxides (TiO ₂ , P ₂ O ₅ ), carbon (C) and ignition loss (Ig) components are excluded. As the raw materials, the main components are SiO ₂ and Al ₂ O ₃ , respectively, and 60.1 wt% and 19.1 wt%, respectively. Particularly, the carbon content is 9.1 wt% and the ignition loss value is 4.9 wt%. It can be seen as an easy composition. However, since the surface of the unburned carbon is hydrophobic, the raw material having a high unburned carbon content is difficult to be mixed with water, so that the molding is difficult. The restraint used in the embodiment of the present invention to be described later is the same as that obtained without ignition loss experiment.

Here, the Riley's blooming zone shown in FIG. 1 shows Riley as an effective composition for blooming at 110 to 1300 ° C, which is the production temperature of a lightweight aggregate by a general firing calcination method Patent Document 4). In Figure 1, the composition of the remainder is shown as "●" (R / A), which is outside the foaming composition area as claimed by Riley, indicating that foaming is difficult with conventional manufacturing methods.

Therefore, in the present invention, it is generally required to use the above-described composition of the above-mentioned composition as a raw material, but it is a new method that does not depend on the conventional firing firing method, that is, And a method of manufacturing an artificial lightweight aggregate through a series of processes.

First, in the present invention, the step of introducing the raw material into the pre-heated firing furnace is a step of introducing the raw material into the firing furnace preheated to a specific temperature in consideration of the rate of temperature rise to the final firing temperature. The most suitable preheating temperature for the heating rate is 800 to 1000 占 폚, preferably 800 to 900 占 폚.

Thereafter, the baking furnace into which the raw material is charged is heated and fired. In the present invention, the furnace is uniformly foamed by keeping the furnace at a temperature elevation temperature and a final temperature elevating temperature for a certain time. That is, unlike the direct firing method in which the sintering is performed from the beginning at the final firing temperature, the firing can be performed at an elevated temperature, so that the entire material can be oxidized without distinguishing between the surface and the interior of the material. On the other hand, in the case of the direct firing method, a black core phenomenon in which a black portion appears inside the reducing atmosphere inside the material during firing appears, so that uniform foaming characteristics do not appear. Specifically, the reason why the black core is shown in the cross-sectional structure of the flame-fired material is that the material is directly introduced into the firing furnace heated to the firing temperature without raising the temperature to form a liquid phase on the surface of the material rapidly, So that the iron oxide remaining in the material is reduced to form a black core and a black core is formed. At this time, promoting the reduction of iron oxide is a carbon oxidation reaction, and the carbon dioxide gas generated thereby promotes foaming of the specimen. On the other hand, the specimen produced by the temperature elevation firing method generates gas before the liquid phase is formed and escapes out of the specimen, so that the inner iron oxide is not reduced and the black core is not formed.

In the present invention, the temperature rise can be performed at a rate of 1 to 30 ° C / min, preferably 5 to 20 ° C / min, more preferably 10 to 15 ° C / min. When the temperature raising rate is slower than 1 ° C / min, it is possible to have a very uniform foaming property, but the gas inside the material tends to escape from the specimen, so that the specific gravity may be relatively high, which may be disadvantageous in terms of thermal efficiency. When the temperature raising rate is higher than 30 ° C / min, the internal gas is hardly escaped from the specimen, so that the foaming performance is improved, so that relatively large pores are distributed. However, There is a possibility that a black core is formed due to the reduction of iron oxide by inducing a reducing atmosphere inside.

The heating can be performed until the final temperature is 1200 to 1300 ° C, preferably 1250 to 1275 ° C, and the final heating temperature is maintained for 1 to 30 minutes, preferably 5 to 15 minutes. Can be completed. In the case where the temperature of the final temperature is relatively low or the firing holding time is short, the gases generated by combustion of the unburned carbon and the organic compounds in the temperature raising process can sufficiently escape from the specimen. Also, Densification can be performed, but the specific gravity can be relatively increased, and the amount of liquid phase formed on the surface can be decreased, so that the water absorption rate can be increased. In addition, when the final temperature rise temperature is relatively high or the firing holding time is long, the specimen undergoes viscoelastic behavior due to the formation of a liquid phase in the specimen due to high-temperature firing, which causes the generated gases to swell out of the specimen The specific gravity can be lowered and the amount of liquid phase formed on the surface can be increased to decrease the water absorption rate, but it may be disadvantageous in terms of thermal efficiency and specimen strength.

Example  One

A 15% by weight aqueous solution of polyvinyl acetate (PVA) was added in an amount of 15 to 20 wt% in order to prepare the solids representing the composition of Table 1 and to improve the molding ability of the solids. From this, a spherical shaped body having a diameter of 8 mm . The formed body was dried at 110 ° C. for 24 hours, put into a preheated firing furnace at 800 ° C., heated and fired at a heating rate of 5 ° C./min, calcined at a final temperature of 1200 ° C. for 10 minutes, And the artificial lightweight aggregate was produced.

Example 2

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the final temperature elevation temperature was adjusted to 1225 캜 in Example 1.

Example  3

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the final temperature elevation temperature was adjusted to 1250 캜.

Example  4

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the final temperature elevation temperature was adjusted to 1275 캜 in Example 1.

Example  5

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the heating rate was controlled at 10 ° C / min in Example 1.

Example  6

An artificial lightweight aggregate was prepared in the same manner as in Example 5, except that the final temperature elevation temperature was adjusted to 1225 캜 in Example 5.

Example  7

An artificial lightweight aggregate was prepared in the same manner as in Example 5, except that the final temperature elevation temperature was adjusted to 1250 캜.

Example  8

An artificial lightweight aggregate was prepared in the same manner as in Example 5, except that the final temperature elevation temperature was adjusted to 1275 캜 in Example 5.

Example  9

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the temperature raising rate was controlled at 15 ° C / min in Example 1.

Example  10

An artificial lightweight aggregate was prepared in the same manner as in Example 9, except that the final heating temperature was adjusted to 1225 캜.

Example  11

An artificial lightweight aggregate was prepared in the same manner as in Example 9, except that the final temperature elevation temperature was adjusted to 1250 캜.

Example  12

An artificial lightweight aggregate was prepared in the same manner as in Example 9, except that the final heating temperature was adjusted to 1275 캜 in Example 9.

Example  13

An artificial lightweight aggregate was prepared in the same manner as in Example 9, except that the preheating temperature was adjusted to 900 캜 in Example 9.

Example  14

An artificial lightweight aggregate was prepared in the same manner as in Example 10, except that the preheating temperature was adjusted to 900 캜 in Example 10.

Example  15

An artificial lightweight aggregate was prepared in the same manner as in Example 11, except that the preheating temperature was adjusted to 900 캜 in Example 11.

Example  16

An artificial lightweight aggregate was prepared in the same manner as in Example 12, except that the preheating temperature was adjusted to 900 캜 in Example 12.

Example  17

An artificial lightweight aggregate was prepared in the same manner as in Example 9, except that the preheating temperature was adjusted to 1000 캜 in Example 9.

Example  18

An artificial lightweight aggregate was prepared in the same manner as in Example 10, except that the preheating temperature was adjusted to 1000 캜 in Example 10.

Example  19

An artificial lightweight aggregate was prepared in the same manner as in Example 11, except that the preheating temperature was adjusted to 1000 캜 in Example 11.

Example  20

An artificial lightweight aggregate was prepared in the same manner as in Example 12, except that the preheating temperature was adjusted to 1000 캜 in Example 12.

Comparative Example  One

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the firing was carried out at 1200 ° C for 10 minutes in Example 1.

Comparative Example  2

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the firing was carried out at 1,225 ° C for 10 minutes in Example 1.

Comparative Example  3

An artificial lightweight aggregate was prepared in the same manner as in Example 1 except that the direct fired at 1250 ° C for 10 minutes in Example 1.

Comparative Example  4

An artificial lightweight aggregate was prepared in the same manner as in Example 1, except that the firing was carried out at 1275 캜 for 10 minutes in Example 1.

Experimental Example  One

In order to confirm the internal structure of the specimen and the specific gravity characteristics of the artificial lightweight aggregate produced according to the present invention in accordance with the temperature raising rate and the final temperature rise temperature, the artificial lightweight aggregate produced according to Examples 1 to 12 and Comparative Examples 1 to 4, (DCS-105, Sometech Vision, Korea). The results are shown in Table 2 below. The specific gravity (KS F 2503) was measured and compared with FIG. 2.

Referring to FIG. 2, the specimens prepared using the temperature elevation firing method according to the present invention showed a slight specific gravity difference according to the heating rate, but the specimens prepared at the final temperature elevation temperature of 1225 ° C. 2, 6, and 10), and the specific gravity of the specimens prepared at the final elevated temperature (Examples 3, 4, 7, 8, 11, and 12) was drastically decreased. The high specific gravity of the specimens (Examples 1, 2, 5, 6, 9, 10) that were fired at a relatively low temperature of 1200 ~ 1225 ℃ was due to the combustion of unburned carbon and organic compounds And the oxide particles are expected to be densified by heating and firing. However, in the specimens (Examples 3, 4, 7, 8, 11, and 12) in which the final temperature elevation temperature is higher than 1250 ° C. (Examples 3, 4, 7, 8, 11 and 12), viscoelastic behavior of the specimen is shown As the generated gases swell without being able to escape from the specimen, the specific gravity value is lowered.

This phenomenon is described with reference to Table 2 above. In the specimens fired at 1200 to 1225 ° C (Examples 1, 2, 5, 6, 9 and 10), foaming was relatively weak, The specimens (Examples 3, 4, 7, 8, 11 and 12) which were fired at a temperature of 1250 ° C or higher (Examples 3, 4, 7, 8, 11 and 12) exhibited a so-called honeycomb structure . It can also be seen that the specimens fired at a heating rate of 15 DEG C / min (Examples 9 to 12) have larger pore sizes than the specimens fired at different heating rates (Examples 1 to 8).

On the other hand, referring to Table 2, another characteristic of the cross-sectional structure of the aggregate manufactured by the temperature elevation firing method is that all specimens are oxidized without distinguishing between the surface and the interior regardless of the heating rate and the final firing temperature. That is, it can be confirmed that the black portion fired in the reducing atmosphere does not appear in the specimen.

In contrast, referring to FIG. 2, in the case of specimens prepared by the direct firing method, the specific gravity value tends to decrease slowly as the firing temperature increases, but does not show a large change within the range of 1.2 to 1.3 . Compared with the specimens manufactured by the heating and firing method, the specimens fired at a specific gravity value of 1200 to 1225 ° C (Comparative Examples 1 and 2) were as low as 24 to 38%, and the fired specimens (Comparative Examples 3 and 4) are similar or somewhat higher.

Also, referring to Table 2, it is generally determined whether or not a black core is formed in the case of the ceramic aggregate sintered by the direct firing method. In the specimen fired at 1200 ° C (Comparative Example 1) Thus, it can be seen that foaming has occurred. As a result, the specific gravity of the flame-fired specimen is lower than that of the high-temperature firing specimen even at the same firing temperature. As described above, the reason why the black core is shown in the cross-sectional structure of the flame-fired test piece is that the material is directly put into the furnace heated to the firing temperature without a temperature rise process. That is, the liquid phase is rapidly formed on the surface of the material, and the inside is blocked with the outside air to become the reducing atmosphere, and the iron oxide remaining in the inside is reduced to form the black core and the black core. At this time, promoting the reduction of iron oxide is an oxidation reaction of carbon, and the generated carbon dioxide gas promotes foaming of the specimen. On the other hand, the specimens fired by the temperature elevation firing method generate gas before the liquid phase is formed and escape out of the specimen, so that the inner iron oxide is not reduced and the black core is not formed. Therefore, as shown in Table 2, the specimens produced by the flame firing had black cores generated at all sintering temperatures and exhibited a foam behavior, and in the case of specimens manufactured at a sintering temperature of 1200 to 1225 DEG C, specific gravity was equal to Which is lower than that of the specimen prepared at the final temperature elevation temperature.

Experimental Example  2

In order to confirm the absorption rate characteristics of the artificial lightweight aggregate produced according to the present invention in accordance with the heating rate and the final heating temperature, the surface of the artificial lightweight aggregate produced according to Examples 1 to 12 and Comparative Examples 1 to 4 was observed with an optical microscope (DCS-105, Sometech Vision, Korea). The results are shown in Table 3, and the results of measurement of water absorption rate (KS F 2503) are shown in FIG.

As shown in FIG. 3, in the case of the specimen manufactured using the temperature-elevation firing method according to the present invention, the specimen fired at 1200 ° C. (Examples 1, 5, and 9) exhibited an absorption rate of 15 to 18% (Examples 3, 4, 7, 8, 11, and 12) at the firing temperature were drastically decreased to 0 to 1% in the specimens fired at 1225 ° C (Examples 2, 6, It can be seen that there is almost no change in absorption rate. The specimens fired at 1225 ℃ were sufficiently densified and the absorptivity decreased sharply. The specimens fired at temperatures higher than 1225 ℃ showed near 0% absorptivity due to the magnetization behavior.

This phenomenon is shown in Table 3 above. In the test pieces fired at 1200 ° C (Examples 1, 5 and 9), no liquid phase was observed on the surface, but the liquid phase amount formed on the surface increased as the firing temperature was higher . That is, as the amount of liquid on the surface increases, the open pore of the surface is filled up, and the absorption rate is rapidly decreased.

In contrast, FIG. 2 shows that the specimen manufactured by the direct firing method had a higher overall absorption rate than the specimen manufactured by the temperature-elevation firing method. The specimens fired at 1200-1225 ° C (Comparative Examples 1 and 2) had a water uptake of 22%, but the specimens fired at 1250 ° C (Comparative Example 3) increased to 28% and the specimens fired at 1275 ° C Comparative Example 4) slightly decreased to 25%.

As described above, the reason why the water absorption rate during the direct firing is high is considered in connection with the cross-sectional microstructure shown in Table 2. There are pores larger in the shell of the specimen than in the black core portion, (Open pore), and thus the absorption rate is high. On the other hand, the absorption rate of the fired specimen (Comparative Example 4) at the highest temperature of 1275 ° C was lower than that of the specimen fired at 1250 ° C (Comparative Example 3) because a relatively large amount of surface liquid phase As shown in Table 3, the surface of the specimen fired at 1275 ° C (Comparative Example 4) had more liquid phase than the specimen fired at 1250 ° C (Comparative Example 3) .

Experimental Example  3

In order to confirm the specific gravity and the water absorption characteristics according to the preheating temperature (sintering furnace injection temperature) of the artificial lightweight aggregate produced in accordance with the present invention, the specific gravity (KS F 2503) and moisture The absorption rate (KS F 2503) was measured and the results are shown in comparison with FIGS. 4 and 5. The results for the artificial lightweight aggregate prepared according to Examples 9 to 12 are also shown for comparison.

First, referring to FIG. 4, it can be seen that the specific gravity of the specimen is the same regardless of the preheating temperature. That is, the specific gravity of the specimens fired at 1225 ° C (Examples 10, 14 and 18) was higher than that of the specimens fired at 1200 ° C (Examples 9, 13 and 17) The specimens fired at 1275 ° C (Examples 12, 16 and 20) exhibited a lightweight property with a specific gravity close to 1.0, regardless of the preheating temperature, in particular, in Examples 11, 12, 15, 16, 19 and 20 As shown in Fig.

Here, the specific gravity of the specimens (Examples 10, 14 and 18) fired at a temperature of 1225 ° C is higher than that of the specimens fired at 1200 ° C (Examples 9, 13 and 17) And the oxide particles become dense during the heating and firing process. However, in the case of specimens fired at a temperature of 1225 ° C or higher, the specimens exhibit viscoelastic behavior due to high-temperature firing, so that the internal gases are swollen and the specific gravity is lowered.

Also, referring to FIG. 5, it can be seen that the absorption rate of the specimen showed the same tendency in all specimens regardless of the preheating temperature. That is, in the specimens fired at 1200 ° C. (Examples 9, 13 and 17), the water absorption rate was 12 to 15%, but in the specimens fired at 1225 ° C. (Examples 10, 14 and 18) (Examples 11, 12, 15, 16, 19, and 20) showed almost no change in the water absorption rate.

According to the results of specific gravity and water absorption of the artificial lightweight aggregate according to the above preheating temperature, it is possible to manufacture an artificial lightweight aggregate having satisfactory physical properties without a large change in the preheating temperature range of 800 to 1000 캜 according to the present invention, It can be confirmed that the change in the preheating temperature is not an important factor when the liquid forming temperature is lower than 1225 ° C.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (14)

A method of manufacturing an artificial lightweight aggregate using a material made of reject ash,
(a) injecting the material into a preheated kiln;
(b) heating the kiln into which the material is introduced;
(c) maintaining a predetermined time at the final elevated temperature after completion of the elevated temperature; And
(d) discharging the fired material from the firing furnace after the predetermined period of time has elapsed;
And a method of manufacturing an artificial lightweight aggregate using the elevated temperature firing method. The method of claim 1,
The preheating temperature of step (a) is artificial light aggregate production method using a temperature rising firing method, characterized in that 800 ~ 1000 ℃. 3. The method of claim 2,
The step of (b) the temperature rise is artificial lightweight aggregate manufacturing method using an elevated temperature firing method, characterized in that carried out at a temperature increase rate of 1 ~ 30 ℃ / min. 3. The method of claim 2,
The step of (b) the temperature rise is artificial lightweight aggregate production method using a temperature rising firing method, characterized in that carried out at a temperature increase rate of 5 ~ 20 ℃ / min. 3. The method of claim 2,
The step of (b) the temperature rise is artificial lightweight aggregate manufacturing method using a temperature rising firing method, characterized in that carried out at a temperature increase rate 10 ~ 15 ℃ / min. The method of claim 3,
The final elevated temperature of step (c) is artificial light aggregate production method using a temperature rising firing method, characterized in that 1200 ~ 1300 ℃. The method of claim 3,
The final elevated temperature of step (c) is an artificial lightweight aggregate manufacturing method using an elevated temperature firing method, characterized in that 1250 ~ 1275 ℃. The method according to claim 6,
The predetermined time of step (c) is artificial light aggregate manufacturing method using a temperature rising firing method, characterized in that 1 to 30 minutes. The method according to claim 6,
The predetermined time of step (c) is artificial lightweight aggregate manufacturing method using a temperature rising firing method, characterized in that 5 to 15 minutes. An artificial lightweight aggregate formed by heating and calcining a material composed of a reject ash, and based on an internal cross section of the artificial lightweight aggregate, an iron oxide component present therein is not reduced, so that an adjacent portion of the outermost surface of the artificial lightweight aggregate is not reduced. An artificial light weight aggregate formed by foaming by oxidizing the whole inside without the internal interface. 11. The method of claim 10,
The artificial light weight aggregate is artificial light weight, characterized in that the specific gravity (KS F 2503) is 1.0 ~ 1.5. 11. The method of claim 10,
The artificial light weight aggregate is artificial light weight, characterized in that the specific gravity (KS F 2503) is 1.0 ~ 1.2. 11. The method of claim 10,
The artificial lightweight aggregate is artificial lightweight aggregate, characterized in that the water absorption rate (KS F 2503) is 0 to 18%. 11. The method of claim 10,
The artificial lightweight aggregate is artificial lightweight aggregate, characterized in that the water absorption rate (KS F 2503) is 0 ~ 1%.

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