KR101052481B1 - Crystalized glass using a coal bottom ash having improved hardness of surface by inducing surface crystallization and preparing process thereof - Google Patents

Abstract

The present invention relates to a crystallized glass using a coal flooring material having improved surface hardness through induction of surface crystallization, and a method of manufacturing the same. The method of manufacturing crystallized glass using a coal flooring material having improved surface hardness through surface crystallization induction of the present invention. on the surface, then is that getting the flooring of certain particles sieved to a certain particle size in a subject to the fired coal bottom ash as main the plastic flooring, melting and vitrification at the lithium oxide (Li ₂ O) a predetermined temperature of the obtained bottom ash It is produced by heat treatment through a polishing process before the surface crystallization of the glass using a predetermined size of abrasive paper.

The crystallized glass using the coal flooring material having improved surface hardness through the surface crystallization induction of the present invention, and the manufacturing method thereof, vitrify the coal flooring material discharged from the coal-fired power plant and use a paper of a predetermined size on the surface Thus, a crystallized glass having a better surface hardness is improved by heat treatment through a polishing process before the surface crystallization of the glass, and a method of manufacturing the same.

Surface Crystallization, Glass-Ceramic, Coal Flooring, Surface Treatment, Beta-Spodumene.

Description

Crystalized glass using a coal bottom ash having improved hardness of surface by inducing surface crystallization and preparing process

The present invention relates to crystallized glass using a coal flooring material having improved surface hardness through induction of surface crystallization, and a method of manufacturing the same. More specifically, vitrified coal flooring material discharged from a thermal power plant is vitrified, and abrasive paper having a predetermined size on the surface. The present invention relates to crystallized glass using a coal flooring material having a better surface hardness by heat treatment through a polishing process prior to the surface crystallization of the glass, and a method of manufacturing the same.

In general, most coal ash, which is a waste of thermal power plants, is produced when the coal is burnt in a pulverized coal mill after drying and pulverizing anthracite, bituminous coal, sub-bituminous coal, lignite, and coal. It is collected in the dust collection equipment or collected at the bottom of the boiler, and the amount generated is collected in the dust collection equipment among the whole coal ash, which is 15 to 45% of the total coal dust, and about 6 million tons of coal ash is produced annually in the Korean thermal power plant. Fly ash and bottom ash from the boiler bottom account for 80% and 20%, respectively.

In the case of the fry ash has been steadily researched since the 1980s and is now made of cement substitutes, commercial bricks, blocks and concrete, and most of them are being recycled. However, in the case of flooring, there was a limit in recycling because it is not uniform in composition and shape. That is, the flooring material is irregular in shape, has a porosity, and the size of the particles are also variously unsuitable for use in aggregate, so the recycling performance is insignificant and most of it is buried. Recently, a lot of researches have been conducted for the use of lightweight concrete and sound absorbing materials using the light weight and porosity of the flooring material, which is a huge amount of waste, but its utilization has not been very good yet.

On the other hand, in recent years, research on glass-ceramic using coal flooring for use as artificial marble tiles and structural materials, but it is still insufficiently performed. Therefore, there is a need for comprehensive research to effectively recycle coal flooring.

The use of such flooring as glass discloses, for example, Korean Patent Application No. 2002-0017459, "Low melting point glass composition, crystallized glass composition and its manufacturing method using thermal power plant fly ash". As the main raw material in the present invention, a crystallized glass which is used for building tiles and artificial marble, and has high strength and wear resistance properties by adding a slight oxide to reinforce the CaO component, which helps to improve hardness and wear resistance, and suitable heat treatment after melting. To provide a composition and a method for producing the same, for this purpose "low melting point glass using coal ash, characterized in that composed of 70 to 90% by weight of coal ash and 10-30% by weight of the shell shell calcined as a source of CaO. Composition ".

However, the above method is not only using fly ash of coal, but also using clam shell as a source of calcium oxide, so that glass having a desired hardness, especially a certain level of surface hardness, cannot be obtained. There is a problem.

Accordingly, an object of the present invention is to analyze the dependence of physical properties on the crystallization behavior by controlling the surface crystallization behavior in the production of glass-ceramic by adding Li ₂ O as a reforming oxidant while effectively recycling it using coal flooring as a main material. Therefore, to provide a method for producing a glass having a superior surface hardness.

In particular, the present invention is to investigate the effect of nucleation sites formed on the surface by polishing on the physical properties of glass-ceramic to provide a method for producing glass having a superior surface hardness.

Another object of the present invention is to provide an easy method for producing crystallized glass using coal flooring having improved surface strength.

The above object of the present invention is that the degree of surface crystallization and the crystallization mechanism is determined by non-isothermal and microstructure analysis on SiO ₂ -Al ₂ O ₃ -Li ₂ O glass whose surface comprises coal bottoms treated with abrasives. Investigation completed. In particular, the present invention is a beta-spodumene solid solution for the major crystal phase, the activation energy and abrami coefficient for growth were calculated from differential thermal analysis, respectively, measured to be 263 kJ / mol and 0.99, thus the surface crystallization is better than the volume crystallization. It was. The nucleation sites generated on the surface by the polishing treatment induced surface crystallization, and the hardness of the surface-treated sample was increased due to finer grains than the lake paper and increased the degree of crystallization. It became.

Method for producing a crystallized glass using the coal flooring material to improve the surface hardness through the surface crystallization induction of the present invention for achieving the above object;

Obtain a flooring of certain particles sieved to a certain particle size in the calcined and the calcined coal bottom ash as main flooring, given this surface, after having been melted and vitrified in a lithium oxide (Li ₂ O) a predetermined temperature of the obtained bottom ash It is prepared by the heat treatment through a polishing process before the surface crystallization of the glass using abrasive paper of the size of.

According to another configuration of the present invention, the predetermined size of the abrasive paper is characterized in that the particles are of a fine high lake.

According to another configuration of the present invention, the predetermined size abrasive paper is characterized in that the number 2000.

Crystallized glass using a coal flooring material having improved surface hardness through the surface crystallization induction of the present invention for achieving the above another object;

Obtain a flooring of certain particles sieved to a certain particle size in the calcined and the calcined coal bottom ash as main flooring, given this surface, after having been melted and vitrified in a lithium oxide (Li ₂ O) a predetermined temperature of the obtained bottom ash It is characterized in that it is produced by heat treatment through a polishing process before the surface crystallization of the glass using abrasive paper of the size of.

The crystallized glass using the coal flooring material having improved surface hardness through the surface crystallization induction of the present invention, and the manufacturing method thereof, vitrify the coal flooring material discharged from the coal-fired power plant and use a paper of a predetermined size on the surface Thus, a crystallized glass having a better surface hardness is improved by heat treatment through a polishing process before the surface crystallization of the glass, and a method of manufacturing the same.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated in detail by preferable embodiment, the scope of the present invention is not limited to this.

Coal bottoms typically consist of SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , CaO and other oxides, and can be melted at high temperatures around 1600 ° C, if suitable reforming oxidants are added to the coal floor. If so, it will be possible to effectively reduce the melting point to provide economic utility. To this end, Li ₂ O was used as the reforming oxidant based on data obtained through numerous experiments. Therefore, in order to achieve the above object of the present invention, by controlling the surface crystallization behavior of the glass ceramic containing the flooring material and Li ₂ O to analyze the dependence of the physical properties on the crystallization behavior of the glass having a superior surface hardness The method was analyzed.

To this end, the present invention used a flooring material obtained from a specific thermal power plant in Korea, and decarbonized for 3 hours at 1,000 ℃ to remove non-burned carbon before use. The constituent oxides of the decarbonized coal bottoms were analyzed by X-ray Fluorescence Spectroscopy (XRF) and the percentages are shown in Table 1 below.

oxide
Precursor group Intermediate group Modifier SiO ₂ P ₂ O ₅ ZrO ₂ TiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Na ₂ O K ₂ O MgO CaO MnO Li ₂ O Fired flooring 58.6 0.1 0.4 1.7 23.9 10.4 0.3 0.6 1.0 2.8 0.1 0 Glass 49.8 0.1 0.3 1.4 20.3 8.8 0.2 0.5 0.9 2.4 0.1 15.0

The calcined flooring material is sieved and collected into fine particles of 45 μm or less, mixed with 15 wt.% Of Li ₂ O and dry polished with zirconia balls for 24 hours. The ground mixture is melted for 20 minutes at 1350 ° C. in an alumina crucible in an electric furnace and then poured into a carbon mold at 500 ° C. to form a cube glass.

Non-isothermal analyzes on glass specimens were performed by using DTA between 25 and 1300 ° C. at various heating rates of 5-20 ° C./min. Data obtained from the DTA was used to determine the process for crystallizing the glass most effectively.

The surface layer of the cubic glass-ceramic was cut into a flat shape using a diamond cutter, and the crystal phase was identified as it is by XRD (X-ray Diffractometer, D / MAX-C, Rigaku Co.). The remaining interior of the sample was crushed into 45 μm powder and analyzed by XRD to investigate the volumetric behavior of the sample. The morphology of the surface of glass and glass-ceramic was observed by FESEM (Field Emission Scanning Electron Microscope, JSM-6500F, JEOL Co.). The micro-hardness of the specimens was measured by applying a 300 g load for 30 seconds using a Vickers micro-hardness tester (MXT-α, Matsuzawa Seiki Co.).

The XRD pattern of the fired bottom and the glass composed of 85 wt% bottom and 15 wt% Li ₂ O is shown in FIG. 1. The main crystalline phases of coal floors are quartz and mullite, while the glass composed of 85 wt% bottoms and 15 wt% Li ₂ O is entirely glassy.

The DTA curves obtained at various heating rates are shown in FIG. 2. The intensity of the exothermic and endothermic peaks increased and the position of the peak moved with the heating rate to a higher temperature. The first endothermic peak of about 500 ° C. was the glass transition temperature (T _g ), and the third exothermic peak (T _c ) appearing in the range of 600 to 850 ° C. was identified as crystallization or crystal phase deformation in the glass. The heat treatment temperatures for crystallization are 668 ° C. (T _c 1), 753 ° C. (T _c 2), 823 ° C. (T _c 3), and 732, the termination temperatures of T _c 1 of the peak from the DTA curve (d) shown in FIG. 2. ° C (T _c 4) is selected.

In general, crystallization for forming glass-ceramics is carried out in a two-step method, that is, the growth step following the nucleation step. In the present invention, however, the effect of scratching by polishing the surface on the crystallization behavior was investigated. Therefore, a separate nucleation step is not considered as a necessary step, but a single step method in which the nucleation and growth process proceeds simultaneously is selected.

3 shows the XRD patterns of the inside and the surface of the glass-ceramic heat treated at various crystallization temperatures for 5 hours. Preliminary experiments on heat treatments varying from 1 to 10 hours indicated that the crystal peak intensity in XRD increased with increasing heating time, but was nearly constant after 5 hours, thus making the isothermal heating time 5 hours.

Heat treatment at crystal peak on (668, 753, and 823 ° C.) degrees of all three samples obtained from the DTA of FIG. 2 indicates that volume crystallization is superior to surface crystallization without surface scratching. However, the sample heat-treated at 732 ° C. at the termination temperature of the first crystal peak in DTA and 64 ° C. above that peak has the highest surface crystal peak intensity compared to other samples heat-treated at the crystal peak temperature shown in the DTA curve in XRD.

As shown in FIG. 3A, all specimens have beta-spodumene solid solution, lithium silicate crystals and esonite inside. Meanwhile, as shown in FIG. 3B, the surface of the glass-ceramic shows only two crystalline phases, beta-spodumene and lithium silicate.

The correlation between the crystal volume fraction (x) and time (t) when the glass is heated was proposed by Johnson-Mehl-Avrami (JMA) as follows:

.............. (1)

.............. (One)

Where α is the heating rate, x is the volume fraction of the crystallized phase at time t, and n is the Abrami constant. Surface crystallization predominates in the crystallization process of n close to 1, while volume crystallization predominates in the vicinity of 3. k is a constant for absolute temperature T and can be described by the following Aurenius type equation;

................. (2)

................. (2)

Where E is the activation energy for crystallization, A is a constant, and N is the number of nuclei per unit volume.

The activation energy for crystallization can be calculated with the Kissinger equation:

.................... (3)

.......... (3)

Where T _c is the crystallization temperature at a predetermined heating rate α and R is the gas constant.

및

의 상관관계는 T_c1(668℃)에 대해 도 4에 그래프로 나타나고, 이 탄젠트로 효과적인 활성화 에너지가 263 kJ/mol로 측정된다.

And

The correlation of is shown graphically in FIG. 4 for T _c 1 (668 ° C.), with this tangent an effective activation energy of 263 kJ / mol.

The Abram constant n is determined from the Augis-Bennett equation:

.................... (4)

.................... (4)

Where ΔT is the width of the exothermic peak at maximum intensity.

The value of n of the glass-ceramic crystallized at 668 ° C. is 0.99, indicating predominant surface crystallization. If the activation energy E is high for some crystals, more energy is needed for the crystal growth and therefore it is difficult for the crystal to grow three-dimensionally. According to Equation (4) derived by Augis-Bennett, the Abramie constant n decreases with the activation energy E, so one-dimensional surface crystal growth is advantageous when E is high.

The surface of the material is unstable due to peripherally directed nodules and these surface instabilities play an important role in creating nucleation sites (dysplastic nucleation mechanisms). When the surface is scratched with abrasive paper, the surface becomes rough and the non-surface area increases, increasing the number of potential nucleation sites.

The glass surface is lightly rubbed with three kinds of abrasive paper (800, 1500 and 2000) before heat treatment. XRD results of the glass-ceramic surface treated and crystallized at 732 ° C. for 5 hours are shown in FIG. 5. As the lake of abrasive paper increased, the intensity of the crystal peaks increased. The microstructures of glass and glass-ceramic treated with abrasive paper are shown in FIG. 6. Increasing the number of abrasive papers resulted in finer scratch lines on glass samples, resulting in smaller crystal sizes.

The hardness of the surface-treated glass-ceramic and glass is shown in FIG. 7. The hardness of glass-ceramic increased with increasing lake of abrasive paper. For example, the hardness of a sample treated with 2000 abrasive paper is 726.8 MPa, which is 1.5 times higher than that of glass.

In addition, the hardness of the glass-ceramic depends on the degree of crystallinity as shown in FIG. 5, so that the hardness of the glass is lower than that of any glass-ceramic.

As can be clearly seen in the microstructure shown in Figure 6, it can be seen that the hardness increases as the number of lakes of abrasive paper rubbing the surface increases because finer particles enhance crystallinity.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such modifications and modifications belong to the appended claims. will be.

1 is a graph showing an XRD pattern of a glass composed of calcined flooring and 85 wt% flooring and 15 wt% Li ₂ O;

2 is a graph showing a DTA curve obtained at various heating rates,

3 shows the XRD patterns of the inside and the surface of the glass-ceramic heat treated at various crystallization temperatures for 5 hours,

및

의 상관관계를 나타내는 그래프이고,4 is heat-treated at T _c 1 (668 ℃)

And

Is a graph showing the correlation between

5 shows the XRD results of the glass-ceramic surface treated and crystallized at 732 ° C. for 5 hours,

6 is a microstructure of glass and glass-ceramic treated with abrasive paper, (a) A800G (b) A800X (c) A1500G (d) A1500X (e) A2000G and (f) A2000X,

7 is a graph showing the hardness of the surface-treated glass-ceramic and glass.

Claims (4)

After the fired coal flooring material as a main material, the fired flooring material is sieved to a certain particle size to obtain a constant particle flooring material. The obtained flooring material is mixed with lithium oxide (Li ₂ O), and then melted and vitrified at a predetermined temperature. A method for producing crystallized glass using a coal flooring material having improved surface hardness through induction of surface crystallization, characterized in that the surface of the surface is crystallized by heat treatment before the surface crystallization of glass using 2000 abrasive paper. Crystallized glass using the coal flooring material which improved the surface hardness through the induction of surface crystallization characterized by the above-mentioned. delete delete

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