KR20000045712A - Dried materials using phosphate wasted sludge and production method thereof - Google Patents

Abstract

PURPOSE: Dried materials like wet tiles, aggregates or so on are provided which are light in weight, low in absorption rate, high in compression strength and solidity and recycle wasted sludge to reduce cost and environmental contamination. CONSTITUTION: A production method of dried materials is as follows: a first step which mixes 30-50 wt% of wasted sludge and 20-80 wt% of stabilized agent to form a mixture; a second which dries and forms the mixture; and a third which fires the mixture at 1000-1200°C. The wasted sludge including phosphates with about 20 wt% of water content is more than one selected from sludge groups discharged from silicone wafer production factory, semiconductor factory, liquid crystal display factory and phosphate film painting factory.

Description

Construction Materials Using Phosphate Wastewater Sludge and Manufacturing Method Thereof

The present invention relates to a method for manufacturing building and civil construction materials using wastewater sludge containing phosphate as a raw material, and to a building and civil engineering construction material manufactured as described above, and more particularly, to a silicon wafer manufacturing plant or a silicon wafer processing plant. , After treating the wastewater containing phosphate discharged from the manufacturing plant of the LCD, or the coating plant for the phosphate coating process, can be used as a substitute for gravel during wet tiles or concrete construction by using the by-product sludge The present invention relates to a method of manufacturing building and civil construction materials such as aggregates (stone materials), and to building and civil construction materials manufactured according to the same method.

Conventionally, tiles have been manufactured using natural minerals as raw materials, and these tiles have been attached to the exterior walls of buildings. In this case, however, the heavy weight of the tiles slows down the speed of constructing the tiles on the exterior walls of the building, and the heavy weight of the tiles themselves makes it very likely that the tiles will fall off the exterior walls of the building. In order to prevent the separation of the tiles, the weight of the tiles must be light. In addition, the gravel used as aggregate in the construction of concrete, the lighter weight can reduce the load of the building and brings the effect of extending the life of the building.

In general, wastewater discharged from a silicon wafer manufacturing plant, a silicon wafer processing plant, a liquid crystal display manufacturing plant, or a phosphate film coating plant contains a large amount of phosphate and silica (SiO ₂ ), and the wastewater is treated and included in the wastewater. The wastewater is treated using slaked lime, iron salts, aluminum salts, or organic coagulants to bring the phosphate to below statutory limits. Sludge which is by-produced during the treatment of wastewater containing phosphate is produced by sedimentation and flocculation by the wastewater treatment agent. Since such sludge contains calcium phosphate, silica, alumina, iron oxide, sodium, potassium, magnesium, etc., when the sludge is heated at a high temperature, it is thermochemically unstable, so that the shrinkage is not constant, and color development is unstable. There is.

In order to prevent this phenomenon, minerals such as clay, white clay, kaolin, feldspar, pottery stone or feldspar are usually added in a predetermined amount, and then crushed, filtered, molded, dried and fired, and dried materials such as brick or wet tile are processed. It can manufacture. However, various problems arise when these minerals are added to the sludge. For example, when red clay is used, the shrinkage rate decreases, but the strength and hardness of the fired body decrease, the absorption rate becomes excessively large, and the color of the fired body is colored red or reddish purple due to the iron oxide contained in the red clay. It is difficult to manufacture building materials. In addition, white clay, kaolin to feldspar, etc. are white and have high fire resistance, so that the building materials having various colors can be manufactured by utilizing the inherent colors of sludge, but the strength and hardness of the sintered body are lowered, and the absorption rate is so large that the exterior There is a problem that is not suitable for the manufacture of construction materials used as. In general, feldspar and pottery stone are similar to clay, so they are not suitable for the production of dry materials based on the sludge, but among them, feldspar including apatite crystals used for the production of glaze or magnetic tiles has excellent characteristics. Have However, these apatite feldspars are too expensive to be suitable for application to bricks or wet tiles used as building materials for exterior construction of buildings.

To date, due to the problems described above, wastewater sludge, which is rich in minerals and has soil-like characteristics, is not recycled and is mostly buried. As the landfill wastewater sludge is re-dissolved and penetrated into the soil, there is a problem of becoming a secondary source of pollution not only of soil and groundwater but also of rivers and coasts. Moreover, the enormous cost is applied to the treatment of the wastewater sludge described above, which is a factor in raising the manufacturing cost. Therefore, there is a great demand for recycling the wastewater sludge for use in construction and civil engineering construction materials.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to add a stabilizer to the by-product sludge during the treatment of wastewater in a plant treating wastewater containing phosphate, so that low absorption rate, light weight and Construction such as aggregates from wet tiles including apatite crystals having high compressive strength to wet tiles containing apatite (10CaO · 3P ₂ O ₃ ) crystals, which are components of human teeth, having various colors; It is to provide a construction material such as wet tiles or aggregates manufactured by the same method of manufacturing civil engineering construction materials and the same method.

The sludge discharged from the silicon wafer manufacturing plant, the semiconductor factory processing the semiconductor wafer, the liquid crystal display manufacturing plant, and the phosphate coating plant contains a large amount of phosphoric acid. Therefore, when the sludge is fired at a high temperature, calcium and phosphorus react and react. Apatite crystals, which constitute constituents, precipitate, but have weaknesses in strength and hardness and too high water absorption. In order to achieve the object of the present invention, the present inventors have repeatedly studied the wet tiles and wet type with excellent absorption, compressive strength and hardness by combining appropriate stabilizers to improve these disadvantages and to produce a wet tile having a variety of colors. An aggregate was developed in which tiles were crushed into gravel.

1 is an X-ray diffraction diagram of a silicon wafer sludge fired product fired at 1100 ° C. for 1 hour.

2 is an X-ray diffraction diagram of a phosphate-coated sludge calcined product calcined at 1100 ° C. for 1 hour.

In order to achieve the above object, the present invention comprises the steps of mixing about 30 to 50% by weight of wastewater sludge containing phosphate and about 20 to 80% by weight of a stabilizer to form a mixture, drying and molding the mixture, and It provides a method for producing building and civil engineering construction materials comprising the step of firing the mixture at about 1000 ~ 1200 ℃ and building and civil construction materials such as wet tiles and aggregates produced in the same manner.

The wastewater sludge containing phosphate may be at least one selected from the group consisting of wastewater sludge having a water content of about 20% by weight discharged from a silicon wafer manufacturing plant, a semiconductor manufacturing plant, a liquid crystal display manufacturing plant, and a phosphate film coating plant. use. Preferably, the stabilizer is any one or more selected from the group consisting of clay, clay, feldspar, foundry sand, holding sludge and glaze sludge. Pulverizing the mixture for about 3 hours using a ball mill before the drying of the mixture, wherein drying the mixture is performed at about 110 ° C. for about 48 hours, and calcining the mixture. The temperature rise time to the maximum temperature at about 3 hours, the holding time at the maximum temperature is about 30 minutes, and further comprising the step of cooling to room temperature for about 3 hours after the step of firing the mixture.

Hereinafter, the present invention will be described based on a method of manufacturing a wet tile.

First, phosphate wastewater sludge and glaze sludge, sewage sludge, clay and white clay are mixed in an appropriate ratio, and then put into a ball mill to undergo a grinding process for about 3 hours, and then put into a filter press to obtain a dehydrated cake. Subsequently, after press molding in the shape of a wet tile, the molded body is dried at a temperature of about 100 ° C. for 24 to 48 hours, and then fired at a high temperature of about 1100 to 1200 ° C. to produce a wet tile. In this case, the order for the crystal structure of 10CaO and 3P ₂ O ₅ of the apatite calcium (Ca): it is possible to obtain a stable apatite crystals have to be about a 6: the molar ratio is 10 (P). However, most of the phosphate wastewater sludge components have a large amount of phosphorus (P), so to stabilize them, a small amount of sludge discharged from a brown tube manufacturing plant or a glass tube manufacturing plant containing a large amount of free calcium may form apatite crystals. Can be.

In the present invention, stabilizers that can be used include clay, feldspar, feldspar, pottery stone, kaolin, clay, fly ash, silica, waste foundry sand, glaze sludge and soy sludge, among which glaze sludge must be contained. In addition, three or more kinds may be mixed depending on the firing temperature and the color of the fired product. Based on the case where the water content of the wastewater sludge is 20% by weight, the amount of the stabilizer added is about 5 to 10% by weight of clay, about 20 to 50% by weight of clay, and about 10 to 40 is about glaze sludge. About 10% by weight, and about 10-50% by weight of the sludge is preferable. When the amount of clay added is more than 10% by weight, the hardness of the wet tile is weak and the absorption is large. This red color makes it extremely difficult to produce wet tiles with various colors. If the amount of glaze sludge is less than 10% by weight, the hardness of the wet tile is weak and the absorption rate is large, and when the amount is more than 40% by weight, the fire resistance of the tile is low, which is not suitable. Base sludge is a raw material used in the manufacture of tiles, sanitary ware or insulators, so the tiles can be manufactured by themselves, and when used in combination with wastewater sludge, the amount of addition is not limited. However, since some of the glaze sludge is mixed and discharged, the addition of more than 10% by weight of the sludge to the combination consisting of clay, clay, glaze sludge and wastewater sludge significantly increases the properties of the wet tile, but more than 50% by weight. When added, the refractory degree of the tile decreases and melting occurs.

In the present invention, the firing temperature for producing the wet tile is preferably 1000 to 1200 ℃. When the tile is fired at 1000 ° C. or less, a complete sintering reaction does not occur. When the firing temperature exceeds 1200 ° C., the wet tiles are fused to each other and red iron oxide is changed into reddish purple.

Generally, companies that discharge phosphate-containing wastewater include silicon wafer manufacturing plants, semiconductor factories handling silicon wafers, painting factories for coating phosphate coatings, or liquid crystal display devices for cleaning glass substrates using phosphoric acid. Etc. can be mentioned. The present invention measured the components of the representative wastewater sludge by-produced during the treatment of wastewater in order to utilize the sludge of the wastewater containing the phosphate using an atomic absorption spectrometer, the chemical content of the measured wastewater sludge is shown in Table 1 below. Shown in

Chemical composition of wastewater sludge (unit: mol%) Discharge Silicon Wafer Manufacturing Plant Silicon Wafer Processing Plant Phosphate Coating Plant LCD Display Manufacturing Plant ingredient Si 2.91 8.01 4.67 0.85 Al 1.47 14.82 27.84 11.95 P 35.97 26.70 42.65 37.34 Ca 54.96 28.34 15.37 47.14 Cu - - 0.89 - Mg 3.61 6.80 - - Fe - 1.43 2.18 - Na - 1.12 - - Ce - - - 2.57

Referring to Table 1, in a silicon wafer manufacturing plant, a semiconductor factory, and a liquid crystal display device manufacturing plant, phosphoric acid and acetic acid to nitric acid (or hydrofluoric acid) are etched to etch the surface of a substrate made of silicon (Si) to keep the surface of the substrate flat. Mixed acid), in which case phosphoric acid accounts for most of the concentration. The mixed acid is used in an etching process several times, and when the concentration of the mixed acid becomes thin, it is sent to a wastewater treatment plant for disposal. In a phosphate coating factory, a film composed of an aluminum phosphate suspension is coated on an iron plate, and then the suspension is sent to a wastewater treatment plant for disposal. In order to process the discarded mixed acid and the phosphoric acid contained in the suspension, calcined lime is added and precipitated with calcium phosphate and then removed. In addition, aluminum (Al) salt or iron (Fe) salt is added to remove the trace components remaining in the wastewater and aggregate the precipitate, and then, an organic coagulant is added thereto to separate the wastewater into water and sludge.

In Table 1, silicon, phosphorus (P) and cerium (Ce) are the components discharged from the process of etching the surface of the silicon substrate, aluminum, calcium, iron, magnesium and sodium, etc. are added to treat the phosphate wastewater Derived from precipitants and flocculants. Compounds that can be produced from such wastewater sludge include Ca ₃ (PO ₄ ) ₂ , Ca (OH) ₂ , CaF ₂ , Al (OH) ₃ , SiO ₂ , Fe based on conventional wastewater treatment processes. (OH) ₃ , Na ₂ SO _4, or Mg (OH) ₂ , and the like, and when they are heated at a high temperature, they change to the most stable compound. These sludges are sludges produced through physical and chemical reactions by adding additives such as precipitates such as slaked lime, flocculants such as aluminum sulfate to iron salts, and settling agents such as polyacrylamide, to the wastewater containing phosphate. Although it was fine but fired at a temperature of about 1100 to 1200 ° C., no cracking or bending phenomenon occurred in the fired body, but the hardness of the fired body was weak and its absorption was so large that its practicality as a building material is poor.

In order to prevent this phenomenon, glaze sludge discarded from the process of spraying glaze on products such as tiles, insulators or sanitary ware, and soot sludge discarded from tiles, insulators and sanitary ware factories are added at a high rate of about 1100 ℃ When firing at, the strength and hardness of the fired body not only increased, but also the water absorption tended to decrease significantly. For example, the glaze sludge discarded from the process of manufacturing interior wall tiles is melted at a temperature of about 1000 ° C. because of its low fire resistance, and the glaze sludge discharged from the process of manufacturing exterior tiles and floor tiles is about 1050 ° C. The glaze sludge melted at the temperature of about degree, and discharged from the insulator factory tended to melt at the temperature of about 1100 ℃, and the body of about 1200 ℃. Therefore, since the melting temperature of the glaze sludge and the holding sludge are different from each other, various problems occur when the wet sludge is added to the phosphate wastewater sludge as it is.

Therefore, in the present invention, it is possible to manufacture wet tiles by mixing minerals, such as phosphate wastewater sludge and clay to clay, in glaze sludge and sewage sludge discharged from various processes and baking them in a temperature range of about 1100 to 1200 ° C. To do so. This phenomenon is believed to be due to the fact that glaze sludge having a relatively low melting temperature is melted and diffused into the apatite crystals, thereby decreasing the fire resistance of the apatite. However, when mixing glaze sludge and phosphate wastewater sludge only, although the strength and hardness of the fired body are increased and the water absorption is greatly improved, the shrinkage rate is too large, making it unsuitable for building materials. This problem was found to be solved by adding an appropriate amount of clay, which can increase the degree of fire resistance and shrinkage, and the clay which can increase the viscosity of the sludge and plastic body.

In addition, when the wet tile is manufactured using minerals and sludge containing 5% by weight or more of free calcium, the volume of the fired product is changed into Ca (OH) ₂ by reacting with the moisture contained in the wet tile. Increases, causing the sinter to collapse slowly. In the presence of such free calcium, when calcium phosphate sludge was mixed and calcined at a high temperature, excess phosphorus (P) reacted with free calcium to be converted into stable apatite crystals, thereby reducing free calcium.

As described above, when manufacturing the building materials for construction and civil engineering using phosphate wastewater sludge according to the present invention, not only can prevent environmental pollution, but also in terms of price and quality compared to conventional wet tiles used for building exteriors. There is an advantage to gain an edge. In addition, building materials that are difficult to use as external tiles have the advantage that they can be used as aggregates for gravel at the time of concrete construction by grinding them.

When the phosphate wastewater sludge is recycled as a wet tile according to the present invention, the deformation of the wet tile is not high due to the high fire resistance of the wet tile, but the strength and hardness of the wet tile are below the standard, and the absorption rate becomes too large, so that the glaze sludge and the base sludge By mixing the clay, clay, and the like at an appropriate ratio, it is possible to produce wet tiles having various colors such as apatite crystals that cannot be produced using conventional minerals. In addition, in the present invention, the wet tile and the aggregate can be produced by the same method. Thus, the following examples focus on wet tiles.

According to the present invention, it is possible to manufacture dry materials such as wet tiles and aggregates used for construction and civil engineering using wastewater sludge which is by-produced after treating phosphate wastewater, and these wet tiles and aggregates are light, low absorption rate and compressed Due to its excellent properties of high strength and hardness, wastewater sludge can be recycled to reduce waste disposal costs and to significantly reduce environmental pollution. Therefore, when the wet tile having a natural stone shape is manufactured, it is possible to greatly improve the difficulty of construction and aesthetics of the building appearance by replacing the tile using the conventional mineral, which has a lot of difficulty in construction due to its heavy weight. In addition, when the aggregate according to the present invention is used as a substitute for the conventional gravel, since the bonding strength with the cement and has improved durability, not only can reduce the load of the building itself, but also can extend the life of the building. Furthermore, the wet tile manufactured according to the present invention has apatite crystal structure, which is a component constituting the difference of the human body, and thus also serves as a bio-ceramic.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are not intended to limit or limit the present invention.

Example 1

Characteristics of Sludge

Sintered sludge discharged from the typical silicon wafer manufacturing plant among the plants that etch silicon wafers and glass substrates using phosphoric acid, acetic acid and nitric acid is fired at about 1100 ° C for about 1 hour to produce a fired product. It was. Components of the fired product were examined through an X-ray diffraction test (using D / Max. IIA, Rigaku's X-ray diffractometer), and the results are shown in FIGS. 1 and 2. Referring to FIG. 1, it can be seen that the sludge discharged from the silicon wafer manufacturing plant is composed of apatite crystals which are stable at high temperature. As shown in FIG. 2, the sludge discharged from the phosphate coating plant was found to be composed of apatite crystals and AlPO ₄ crystals (which have a melting point of about 1840 ° C.) having excellent fire resistance.

The sludge discharged from each plant was dried at about 110 ° C. for about 4 hours to have a water content of about 2% by weight or less. Subsequently, about 1.5 g of sludge was produced in the shape of a disk having a diameter of about 2 cm, and then dried at about 110 ° C. for about 10 hours. Subsequently, the molded body was maintained at 1000 ° C., 1100 ° C., and 1200 ° C. for about 30 minutes at a heating rate of about 3 ° C./min, respectively, to prepare a fired product, and then weight loss and shrinkage were measured. The results are shown in Table 2 below.

Weight loss (wt%) and shrinkage rate (%) according to the type of sludge and firing temperature Firing temperature and characteristics 1000 ℃ 1100 ℃ 1200 ℃ Type of sludge Weight loss Shrinkage Weight loss Shrinkage Weight loss Shrinkage Silicon Wafer Manufacturing Plant 15 5 16 6 16 6 Phosphate Film Manufacturing Plant 18 8 19 10 19 10

Referring to Table 2, the decomposition of the compound existing in the form of water and organic matter and precipitate occurs up to 1000 ℃, it was found that the weight loss of the sludge is almost completed at 1100 ℃. At 1200 ° C, the sludge discharged from the silicon wafer manufacturing plant maintained the white color as at 1000 ° C and 1100 ° C, but the sludge discharged from the phosphate coating factory contained iron (Fe) and thus 1000 ° C and 1100 ° C. The color of red is different from red, which is the color of Esau.

From these results, even though the two types of sludge alone precipitate apatite crystals that are stable at high temperature, the sludge has a high stability, but has a disadvantage in that the absorption rate of the fired product is large and the hardness is small.

Example 2

Preparation of Wet Tile Added Stabilizer

The sludge discharged from the silicon wafer manufacturing plant, the sludge discharged from the silicon wafer processing steel, and the sludge discharged from the liquid crystal display manufacturing plant have similar characteristics, and all of the sludge discharged from the silicon wafer manufacturing process is produced in this embodiment. This section describes a method for producing wet tiles based on sludge discharged from sludge and phosphate coating factory.

Since the sludge discharged from the silicon wafer manufacturing plant is thermally stable, but the hardness is too weak and the absorption is too high, it is very important to add a suitable stabilizer to produce a good quality exterior tile with a beautiful appearance. In this embodiment, wet tiles were prepared using clay, clay, glaze sludge, and base sludge as the stabilizer.

First, various combinations of clay, clay, glaze sludge and beef sludge were added to sludge having a water content of about 20% by weight, and then ground in a ball mill for about 3 hours. Subsequently, after the filtration process, the mold was formed into a tile having a length, a width, and a thickness of about 20 cm × 5 cm × 2.5 cm, and then dried at about 110 ° C. for about 48 hours. Subsequently, the molded body was put into an electric furnace, and then calcined at 1000 ° C, 1050 ° C, 1100 ° C, 1150 ° C, and 1200 ° C, respectively, and then cooled. In this case, the temperature increase time to the maximum temperature increase temperature is about 3 hours, the holding time at the maximum temperature is about 30 minutes, and the cooling time to room temperature was adjusted to about 3 hours.

In the measurement of the compressive strength of the tiles, a surface having a length and width of 20 cm × 5 cm was used as the pressing surface, and the pressing surface was uniformly pressed with a paper spatula, and the pressing speed was 10 kgf / cm ² per ^second . The maximum load when the sample was broken was measured. As for the hardness of the tile, the hardness of the surface of the tile was measured using a morse hardness tester. In addition, the absorption is measured by drying the tile at about 120 ° C. for about 24 hours, then heating it in boiling water for about 3 hours, allowing it to cool to room temperature, and then immediately wipe the surface of the tile with a wet towel and weigh it. Absorption was measured by calculating the difference from the previous weight. Subsequently, it was immersed in water for about 10 days in order to measure the stability against hydration (hydration), and then examined for an increase in volume, and an acetic acid solution having a concentration of about 4% to observe durability against acid rain. After soaking for 24 hours, the eluted calcium (Ca) and silicon (Si) components were analyzed using an atomic absorption spectrometer.

When the tile without glaze sludge was fired at any temperature below 1050 ℃, the compressive strength was less than 100kgf / cm ² , the absorption was more than 5%, the morse hardness was less than 4, and no hydration occurred. The components eluted in the acid were eluted from the calcium and silicon components from the tile fired at 1000 ° C and 1050 ° C. However, when the firing temperature was raised to 1200 ℃, the compressive strength of the tile was increased to 150kgf / cm ² , the absorption rate was less than 3%, the morse hardness was 7, hydration and no leaching to acid occurred.

In order to improve these characteristics, 10 to 30% by weight of glaze sludge in a combination consisting of 5 to 10% by weight of clay, 20 to 50% by weight of clay, 30 to 50% by weight of silicon wafer sludge, and 5 to 10% by weight of sludge sludge. The tiles were prepared by firing at the respective temperatures according to the method described above.

As the amount of added clay increases, the fire resistance of the tiles increases, but the hardness decreases and the absorption rate increases. The most suitable addition amount of clay was about 5% by weight. As the amount of clay is increased, the color of the tile is changed to red, making it difficult to manufacture tiles having various colors. In view of this point, the most suitable amount of clay was 20 to 30% by weight. In addition, when the amount of added phosphate wastewater sludge is 60% by weight or more, as in the case of clay, characteristics such as absorption rate, hardness, and strength of the tile are lowered, so that the amount of added wastewater sludge is fixed at 50% by weight. In consideration of these properties, the results are obtained by combining as follows and calcining at 1150 ° C. to measure various physical properties.

(1) T1 combination: 5% by weight of clay, 30% by weight of clay, 5% by weight of sewage sludge, 50% by weight of wastewater sludge, 10% by weight of glaze sludge.

(2) T2 combination: 5% by weight of clay, 25% by weight of clay, 5% by weight of sewage sludge, 50% by weight of wastewater sludge, 15% by weight of glaze sludge.

(2) T3 combination: 5% by weight of clay, 20% by weight of clay, 5% by weight of sewage sludge, 50% by weight of wastewater sludge, 20% by weight of glaze sludge.

Characteristics of Tiles Baked at 1150 ℃ (Silicon Wafer Wastewater Sludge) Characteristics Absorption rate (%) Compressive strength (kgf / cm ² ) Morse Hardness Sign Language Acid resistance Number T1 4 158 6.2 none Good T2 2 162 6.5 none Good T3 0 167 6.7 none Good

As shown in Table 3, the characteristics of the T3 combination with the addition of 20% by weight of glaze sludge are the best, but the T3 combination has a problem of bending due to the slight melting of the surface of the tile at 1150 ° C. Was not suitable. Therefore, T2 combination with 15 wt% glaze sludge showed the best overall physical properties. The wet tile fired at 1150 ℃ by adding 15 wt% of glaze sludge showed a light pink color, and the absorption rate and compressive strength were sufficient to be used as a wet tile. The physical properties were also excellent but the firing temperature was also lower. In the above combinations, when the amount of wastewater sludge was added, the characteristics such as absorption rate, acid resistance and compressive strength were better, and no hydration occurred, but the firing temperature was higher than 1150 ° C.

Since the weight of the wet tile manufactured by the method according to the present embodiment is about 280 g, which is much lighter than the weight of the tile made of the conventional mineral (about 340 g), the mineral in the preparation of the wet tile having the shape of natural stone The difficulty in construction due to the self-weight of the used wet tile has the advantage that it is significantly reduced when the wet tile according to the present invention is replaced.

The wastewater sludge discharged from the phosphate coating factory was mixed at the same ratio as T1, T2 and T3, and calcined at 1150 ° C. As a result, the color of the calcined product was colored red, and the characteristics of the silicon wafer wastewater sludge shown in Table 3 were as follows. Similar results were shown. However, no melting occurred in the T3 combination of wastewater sludge discharged from the phosphate coating plant. This phenomenon is thought to be due to the fact that the wastewater sludge discharged from the phosphate coating factory contains a lot of AlPO ₄ components with high refractory properties. Tended to be better. In addition, when the glaze sludge was added to about 20% by weight without adding the clay, it was confirmed that the glaze sludge should not be added more than 25% by weight because some melting phenomenon appeared on the surface of the tile.

Example 3

Manufacture of aggregate (stone material)

Aggregate that can be used as a substitute for gravel in concrete construction should be light and have similar characteristics to wet tile. Conventional building using gravel is heavy because its load is heavy on the ground, and the life of the building is shortened in recent years, the development of lightweight aggregates that can lighten the load of the building has been promoted. The wet tiles manufactured according to the present invention are light, have low absorption rates, and have high strength, so that when used as a substitute for conventional gravel by pulverizing a plastic having an external shape that is difficult to be used as a wet tile, binding strength with cement is strong and improved. Because of its durability, it can be used as an excellent aggregate.

According to the present invention, it is possible to manufacture dry materials such as wet tiles and aggregates used for construction and civil engineering using wastewater sludge which is by-produced after treating phosphate wastewater, and these wet tiles and aggregates are light, low absorption rate and compressed Due to its excellent properties of high strength and hardness, wastewater sludge can be recycled to reduce waste disposal costs and to significantly reduce environmental pollution. Therefore, when the wet tile having a natural stone shape is manufactured, it is possible to greatly improve the difficulty of construction and aesthetics of the building appearance by replacing the tile using the conventional mineral, which has a lot of difficulty in construction due to its heavy weight. In addition, when the aggregate according to the present invention is used as a substitute for the conventional gravel, since the bonding strength with the cement and has improved durability, not only can reduce the load of the building itself, but also can extend the life of the building. Furthermore, the wet tile manufactured according to the present invention has apatite crystal structure, which is a component constituting the difference of the human body, and thus also serves as a bio-ceramic.

Claims (6)

Mixing about 30-50% by weight of wastewater sludge containing phosphate and about 20-80% by weight of a stabilizer to form a mixture; Drying and molding the mixture; And And firing the mixture at about 1000 to 1200 ° C. The method of claim 1, wherein the wastewater sludge containing phosphate is any one or more selected from the group consisting of wastewater sludge discharged from a silicon wafer manufacturing plant, a semiconductor manufacturing plant, a liquid crystal display device manufacturing plant and a phosphate film coating plant. Method for manufacturing building and civil engineering construction materials. The method of claim 1, wherein the stabilizing agent is any one or more selected from the group consisting of clay, clay, feldspar, foundry sand, holding sludge and glaze sludge. The method of claim 1, wherein the wastewater sludge containing phosphate has a water content of about 20% by weight. The method of claim 1, further comprising grinding the mixture using a ball mill for about 3 hours before drying the mixture, wherein drying the mixture is performed at about 110 ° C. for about 48 hours. The temperature increase time to the maximum temperature in the step of firing the mixture is about 3 hours, the holding time at the highest temperature is about 30 minutes, further comprising the step of cooling to room temperature for about 3 hours after the step of firing the mixture Method of manufacturing building materials for construction and civil engineering, characterized in that. Construction materials for construction and civil engineering, such as wet tiles and aggregates prepared according to the method of claims 1 to 5.