KR102721947B1 - Clay Brick composition and method of manufacturing the same - Google Patents

Abstract

The present invention provides a method for manufacturing clay bricks, comprising the steps of: a) mixing 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 6 parts by weight of bentonite with respect to 100 parts by weight of bauxite residue; b) crushing the mixture to 1 to 0.5 mm; c) kneading the crushed mixture so that it is evenly distributed to manufacture a clay composition; d) extruding the clay composition using a vacuum clay molder (J.C. Steele & Sons. INC); e) drying the extruded molded body for 72 to 88 hours, placing it in a kiln, preheating and firing it at 800°C to 1,150°C for 15 to 25 hours, and then cooling the clay bricks and packaging them.

Description

{Clay Brick composition and method of manufacturing the same}

The present invention relates to an eco-friendly clay brick composition utilizing bauxite residue, which is an alkaline solid waste generated in the alumina smelting industry, and to a method for manufacturing eco-friendly clay bricks using the same. More specifically, the present invention relates to an eco-friendly clay brick composition which is composed of clay, clay, bottom ash, and bentonite in a specific ratio with bauxite residue, which is a natural raw material, without adding cement, thereby having no cracks, a smooth surface, a high far-infrared ray emissivity, excellent antibacterial and deodorizing effects, vivid color, sufficient flexural strength, and low water permeability, and a method for manufacturing clay bricks using the same.

Bricks used as building materials or flooring materials are classified into clay bricks, sand-lime bricks, refractory bricks, and refractory insulating bricks depending on their materials, firing conditions, and intended use. Clay bricks are building materials made mainly of clay and baked at high temperatures. Since they are mainly made of soil, they have functions such as insulation, moisture control, and far-infrared ray emission, and are widely used as finishing materials for the exterior and interior walls of houses. Compared to cement bricks made mainly of cement, they have higher temperature and humidity control functions and are known to be beneficial to health.

Meanwhile, the amount of bauxite residues, which are industrial wastes generated during aluminum smelting, is rapidly increasing in industrial sites. However, landfill, which was the main method of waste disposal in the past, has reached its limits due to the difficulty of securing landfill sites and environmental pollution caused by landfill. In addition, considering that most wastes can be recycled in some form, landfilling is not a desirable method of disposal as it is a huge waste of available resources. Therefore, various studies are being conducted on clay bricks using wastes that maximize the efficacy of clay, etc., without losing the purity of the clay while utilizing the waste. For example, Korean Patent Publication No. 10-2004-0075842 discloses a method for manufacturing clay bricks by mixing, cutting, and thermally firing a composition including waste gypsum, which is a by-product of an industrial organization, and recycling waste gypsum to produce bricks. Korean Patent Registration No. 10-0664567 discloses a method for manufacturing fired clay bricks by recycling waste rock powder and waste sludge generated from quarries, sewage treatment plants, and incinerators. The method comprises mixing waste such as waste rock powder and waste sludge with a certain amount of clay, mixing a binder with the mixture, bonding and fixing the clay and waste by the binder, and extruding and firing the mixture to produce clay bricks. Korean Patent Registration No. 10-2559127 discloses a method for manufacturing recycled fired clay bricks by mixing a) waste polymer nanofiber nonwoven fabric and soil raw materials including sand, clay, clay, clay, and feldspar. A method for manufacturing an eco-friendly clay brick, comprising the steps of: a) preparing a raw material mixture including: a) adding water to the raw material mixture and maturing it to prepare a maturing mixture; c) molding and drying the maturing mixture to prepare a molded body; and d) firing the molded body to manufacture a clay brick, is disclosed. Korean Patent No. 10-1887089 discloses a method for manufacturing an eco-friendly clay brick, comprising the steps of: first maturing soil generated at a construction site for 6 months or longer; crushing the first-mature soil; and second maturing the crushed soil in a silo for 20 to 40 days. A method for manufacturing clay bricks using soil is disclosed, which comprises the steps of obtaining a clay brick composition by mixing the above-mentioned second-aged soil and an inorganic binder, forming the composition to manufacture a molded article, drying the molded article, and firing the dried molded article. Korean Patent No. 10-0949056 discloses a method for manufacturing a high-strength clay sintered body by adding red mud to a clay composition. Korean Patent No. 10-1510825 discloses a composition for manufacturing clay bricks comprising 30-40 wt% of clay, 10-20 wt% of kaolin, 18-30 wt% of sand, and 20-30 wt% of quartz. Korean Patent No. 10-1127530 discloses a method for manufacturing clay bricks by adding slaked lime produced by processing limestone to yellow soil or kaolin, which has functions such as humidity control, odor removal, and insulation, and a firing temperature and A method for manufacturing multi-colored clay bricks that display different colors depending on the mixing ratio is disclosed, and Korean Patent No. 10-1081908 discloses a clay brick having an antibacterial function by providing an antibacterial function in the glaze of the clay brick, so that the clay brick has antibacterial and antifungal properties by treating the clay molded body with an antibacterial glaze and then firing it without a separate process during the molding of the clay brick. However, it has been difficult to implement an eco-friendly brick composition with excellent durability.

Accordingly, the inventors of the present invention have completed the present invention by confirming that a brick manufactured using a brick composition mixed in a ratio of a step of mixing 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 5 to 6 parts by weight of bentonite with respect to 100 parts by weight of bauxite residue, which is a waste generated from the alumina smelting industry, has no cracks, a smooth surface, a high far-infrared ray emissivity, excellent antibacterial and deodorizing effects, vivid color, sufficient flexural strength, low water permeability, and excellent durability.

Domestic Publication Patent No. 10-2004-75842 Domestic registered patent No. 10-0664567 Domestic registered patent No. 10-2559127 Domestic registered patent No. 10-1887089 Domestic registered patent No. 10-0949056 Domestic registered patent No. 10-1510825 Domestic registered patent No. 10-1127530 Domestic registered patent No. 10-1081908

The purpose of the present invention is The purpose is to provide a clay composition recycled from bauxite residues, which are waste generated from the aluminum smelting industry, etc.

Another object of the present invention is to provide an excellent brick having a high far-infrared ray emissivity, excellent antibacterial and deodorizing effects, vivid color, sufficient flexural strength and low water permeability by combining bauxite residues, clay, clay, bottom ash and bentonite in a specific ratio.

In order to achieve the above object, the present invention provides a method for manufacturing clay bricks, including the steps of: a) mixing 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 5 to 6 parts by weight of bentonite with respect to 100 parts by weight of bauxite residue; b) crushing the mixture into 1-0.5 mm pieces; c) kneading the crushed mixture so that it is evenly mixed to manufacture a clay composition; d) extruding the clay composition using a vacuum kiln (J.C. Steele & Sons. INC); e) drying the extruded molded body for 72 to 88 hours, placing it in a kiln, preheating and firing it at 800°C to 1,150°C for 15 to 25 hours, and then cooling the clay bricks and packaging them.

The clay brick according to the present invention, despite containing bauxite residue, which is an alkaline industrial waste, has some harmful substances neutralized by clay and white clay, and further, alkaline components are decomposed by preheating and firing at 800℃ to 1150℃ for 15 to 25 hours, so that it is harmless to the environment, and not only has no cracks, has a smooth surface, and has a high far-infrared ray emissivity by adding bentonite, has excellent antibacterial and deodorizing effects, and has excellent functional characteristics as a clay brick with a vivid color, high compressive strength, low water permeability, and an attractive appearance.

All terms used herein, including technical or scientific terms described in the present invention, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the contextual meaning of the relevant technology, and should not be interpreted in an ideal or overly formal meaning that is not explicitly defined in this application. In addition, when describing the present invention, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

The present invention provides a method for manufacturing a clay brick, comprising the steps of: a) mixing 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 5 to 6 parts by weight of bentonite with respect to 100 parts by weight of bauxite residue; b) crushing the mixture to 1 to 0.5 mm; c) kneading the crushed mixture so that it is evenly mixed to manufacture a clay composition; d) extrusion-molding the clay composition using a vacuum kiln (J.C. Steele & Sons. INC); e) drying the extrusion-molded molded body for 72 to 88 hours, placing it in a kiln, preheating and firing it at 800°C to 1,150°C for 15 to 25 hours, and then cooling the clay brick and packaging it. The clay brick composition may further include a pigment. It is preferable to use an inorganic pigment as the pigment, and as the inorganic pigment, pigments commonly used in the ceramics industry such as bricks, tiles, and porcelain can be used. Representative examples include manganese dioxide and manganese tetroxide. It is preferable to include 0.1 to 0.2 wt% of the total weight of the clay brick composition including the pigment.

In addition, the above clay, white clay, and bottom ash can be processed using a conventional crusher, and it is preferable to crush the mixture to a particle size of 0.5 to 1 mm. In this range, pores with a smaller size can be formed in the clay brick, and the porosity can also be lowered. On the other hand, if the particle size of the mixture is crushed to less than 0.5 mm, the crushing efficiency may decrease although the efficiency of improving the physical properties is minimal, and if the particle size of the mixture is crushed to exceed 1 mm, the pore size increases, the porosity increases, the absorption rate increases, and the strength decreases.

The above bentonite is an aggregate of fine colloidal substances, exhibits high viscosity, and has a higher cation exchange capacity than other clay minerals, so it acts as a natural binder and has excellent functions as a deodorizing and absorbent agent for indoor and outdoor hazardous substances due to its adsorptive properties. It was also confirmed that it has a high far-infrared ray emissivity.

It is preferable to process the above bentonite into powder form and use 5 to 6 parts by weight. If the bentonite is used in amounts less than 5 parts by weight, the effect of the above-mentioned bentonite is minimal, and if it is used in amounts greater than 6 parts by weight, shrinkage or cracking may occur, so it is preferable to use 5 to 6 parts by weight.

The characteristics of each composition component used in the present invention are as follows.

The above bauxite is also called iron ore. _{Its chemical composition is Al2O32H2O ,} its specific gravity is 2.0, and it comes in colors such as gray, red, brown, and yellow, and is usually lusterless. Bauxite coexists with clay minerals _such as limonite, quartz, feldspar, halloysite, kaolinite, and nontronite. It is produced in laterite, which is formed by the weathering of aluminum-rich rocks in tropical regions, or in terra rossa, which is formed by the weathering of limestone containing aluminum. This bauxite is the most important raw material ore for aluminum.

Bauxite residue is an alkaline solid waste generated in the alumina refining industry. Typically, 1 to 2 tons of bauxite residue is generated per ton of alumina produced. The amount of bauxite residue varies depending on the grade of the bauxite and the production process. However, because it has a high alkaline and heavy metal content, not only does it require a large area of land for long-term storage, but the water that may be seeped out during storage can contaminate the surrounding soil and groundwater, causing various environmental problems. In addition, because the particle size is very fine, it is easy for dust to be generated by the wind, which can cause damage to the surrounding area. Therefore, recycling of bauxite residue has been minimal up to now.

Clay contains fine particles and a lot of oxygen, and has excellent purifying ability and deodorizing and degreasing properties. When not heated, it is similar to ordinary soil, but once heated (over 60℃), the far-infrared radiation (5-15㎛) is outstanding, approaching the energy curve that is most beneficial to the human body. It helps relieve fatigue by maintaining the body temperature of 35℃ in the central part of the human body and increasing blood flow, promoting metabolism. As the functions and efficacy of yellow soil have become widely known, it is being widely used in various fields such as civil engineering and building materials, various health devices, and food.

White clay, also called kaolin, refers to soil that is created when rocks or stones are broken down by chemical reactions such as water or carbonic acid. It is also called kaolin, kaolinite, or china clay, and its main components are kaolinite Al ₂ O ₃ ·2SiO ₂ ·2H ₂ O and halloysite Al ₂ O · SiO ₂ ·4H ₂ O. White clay is easy to manufacture into a paste, and when solidified, each particle maintains a finely divided state that does not coagulate, so it easily drains moisture. It is also known to have special utility according to each use, such as radiating far infrared rays and negative ions that are useful to the human body, but it is mainly used to manufacture pottery, etc.

Bottom ash is the ash component with large lumps or particles that fall to the bottom of the boiler when coal is burned in a thermal power plant. It accounts for about 10% of the amount of coal ash generated. Since the total amount of coal ash generated from domestic thermal power plants is about 6 million tons per year, about 600,000 tons are generated as industrial waste, and active research and development is being conducted to reuse it for lightweight aggregate, sand substitute, filler, road base material, road anti-slip material, embankment and backfill material, lightweight bricks and blocks, etc.

Bentonite is a colloidal hydrous silicon aluminum, with montmorillonite as the main component, accounting for about 90%. It also contains quartz, cristobalite, feldspar, mica, zeolite, calcite, and dolomite. Bentonite is insoluble in organic solvents, but in water, it absorbs water between its thin plate-like crystal layers, swells, and is dispersed in water to create a colloidal dispersion exhibiting high structural viscosity. When the bentonite concentration is increased, it forms a sticky gel like agar. In particular, it is widely used for the purposes of viscosity control, stability improvement, and texture adjustment in emulsified and dispersed products because it improves spreadability and film formation with a refreshing feel without the stickiness or stickiness like organic thickeners. In addition, when used together with other water-soluble polymers, it is excellent in preventing discoloration of pigments, so it is often used in colored products.

Hereinafter, the method for manufacturing clay bricks of the present invention using the above components will be described in detail through examples.

<Example 1>

A clay composition was prepared by crushing 100 kg of bauxite residue, 60 kg of clay, 60 kg of white clay, 10 kg of bottom ash, and 6 kg of bentonite to 0.7 mm and mixing the mixture so that it was evenly distributed.

The above clay composition was extruded using a vacuum molder (J.C. Steele & Sons. INC) to produce a molded body, dried for 75 hours, placed in a kiln, preheated and fired at 1100°C for 20 hours, and then cooled to form a clay brick.

<Examples 2 and 3 and Comparative Examples 1 and 2>

As described in [Table 1] below, all processes were carried out in the same manner as in Example 1, except that each component of the clay composition was changed.

Bauxite
Residue (Kg) clay
(Kg) White clay
(Kg) Bottom Ash
(Kg) Bentonite
(Kg) Example 2 100 65 60 10 6 Example 3 100 60 65 10 5 Comparative Example 1 100 0 10 0 15 Comparative Example 2 80 5 0 0 0

The present invention utilizes bauxite residues discarded as waste, and when the mixing ratio of bauxite residues and clay, bentonite, clay, and bottom ash is appropriately adjusted, clay bricks with high strength and excellent color can be manufactured. The results of analyzing the chemical compositions of clay, bauxite residues, and clay used in the present invention are shown in [Table 2] below.

SiO ₂ Fe ₂ O ₃ Al ₂ O ₃ MgO CaO _Na2O TiO ₂ Bauxite residue 8.0 40.1 27.5 1.1 7.2 8.0 8.7 clay 65.3 3.5 12.0 2.5 1,3 1.6 0.5 White clay 68.5 1.5 11.3 1.7 1.2 0.5 1.0

The above bauxite residue contains a large amount of sodium and iron, so that when red bricks are manufactured in a single phase, there are problems such as excessive shrinkage, warping, reduced strength, and poor firing. However, since the alkaline ions _Na2O and CaO, etc. are contained in a high content compared to clay or white clay used as a raw material for the clay composition, a molten glass liquid phase can be easily formed. The formation of the above molten glass liquid phase promotes fluidity and sintering between particles, and has the effect of solving the above problems. In addition, the color of the clay sintered body can be variously adjusted by inducing various natural coloring without additives such as pigments depending on the addition of bottom ash and bentonite. As described in the above <Example 1> and [Table 1], tests were conducted on the compressive strength, flexural strength, absorption rate, and apparent porosity of the clay bricks manufactured by the methods of the examples and comparative examples of the present invention. The test results are as shown in [Table 3].

Compressive strength (MPa) Flexural strength (MPa) Absorption rate (%) Apparent porosity (vol%) KS standard 24.4 and above 5.0 and below 10.0 and below - Example 1 45.2 7.1 5 9.5 Example 2 46.2 7.0 4.9 9.8 Example 3 42.1 6.5 5.0 13.5 Comparative Example 1 34.1 7.0 7.8 22.0 Comparative Example 2 41.0 4.5 8.2 12.5

As can be seen from the above [Table 3], the compressive strength, flexural strength, absorption rate, and apparent porosity of the clay bricks manufactured according to the examples of the present invention were found to be very excellent. In particular, when bauxite was used, the compressive strength was found to be excellent, and in the case of Comparative Examples 1 and 2 where bauxite was not used, the compressive strength was found to be low. Therefore, it was confirmed that the compressive strength, flexural strength, absorption rate, and apparent porosity can all be improved only when the combination of components and the appropriate mixing ratio suggested in the present invention are all satisfied.

Claims (3)

A clay brick using a clay composition, wherein 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 5 to 6 parts by weight of bentonite are mixed in a ratio of 100 parts by weight of bauxite residue, the mixture is ground to 1 to 0.5 mm, and the mixture is kneaded so as to be evenly distributed, and the clay brick has a compressive strength of 42.1 to 46.2 MPa, a flexural strength of 6.5 to 7.1 MPa, and an absorption rate of 4.9 to 5.0%. a) A step of mixing 60 to 65 parts by weight of clay, 60 to 65 parts by weight of white clay, 10 parts by weight of bottom ash, and 5 to 6 parts by weight of bentonite with respect to 100 parts by weight of bauxite residue;
b) a step of grinding the mixture into 1 - 0.5 mm;
c) a step of preparing a clay composition by mixing the above-mentioned crushed mixture so that it is evenly mixed;
d) A step of extruding the above clay composition using a vacuum molder (JCSteele & Sons. INC).
e) a step of drying the extruded molded body for 72 to 88 hours, placing it in a kiln, preheating and firing it at 800°C to 1,150°C, and then cooling it; a method for manufacturing a clay brick, characterized in that the clay brick has a compressive strength of 42.1 to 46.2 MPa, a flexural strength of 6.5 to 7.1 MPa, and an absorption rate of 4.9 to 5.0%. In the second paragraph,
A method for manufacturing clay bricks, characterized in that the extruded molded body is preheated and fired for 15 to 25 hours and then cooled.