WO2006137626A1

WO2006137626A1 - Glaze-free stone tile and manufacturing method thereof

Info

Publication number: WO2006137626A1
Application number: PCT/KR2005/003631
Authority: WO
Inventors: Boo-Soo Choi
Original assignee: Boo-Soo Choi
Priority date: 2005-06-21
Filing date: 2005-10-31
Publication date: 2006-12-28

Abstract

The present invention relates to a method of manufacturing a glaze-free stone tile, comprising the steps of (a) blending 65 to 75 weight parts of natural rock and 25 to 35 weight parts of clay as raw materials with each other; (b) finely pulverizing the raw materials blended in step (a) by a wet type pulverizer; (c) removing iron from the raw materials pulverized in step (b); (d) spray-drying the iron-removed raw materials obtained in step (c); (e) removing iron from the raw materials dried in step (d); (f) mixing the iron-removed raw materials obtained in step (e) using a mixer; (g) molding the mixed raw materials into a molded product in the form of a tile by applying a pressure of 300 to 400kgf/cm2 to the raw materials mixed in step (f) by means of a press; and (h) heating the molded product obtained in step (g) to a temperature of 1,200 to 1,350° C. A stone tile of the present invention has superior waterproof property, high strength, and an absorbency of 1% or less in a finished product even though it is not subjected to glaze treatment, and can prevent discoloration generated due to oxidation of iron contained in the finished product, so that the stone tile can be used as construction materials by substituting for a natural rock.

Description

GLAZE-FREE STONE TILE AND MANUFACTURING

METHOD THEREOF

Technical Field

[1] The present invention relates to a stone tile, and more particularly, to a glaze-free stone tile that is not deformed or discolored, has high surface strength even without glaze treatment and shows stone texture, and a manufacturing method thereof.

[2]

Background Art

[3] A natural rock such as granite is widely used for decorating the interior and the exterior of a building. Since the natural rock can be used for construction after being processed in advance into a predetermined shape corresponding to the structure or installation specification of a building, there are problems in that much manpower and time are required for processing the natural rock, the unit cost of a natural rock product is very high, it is difficult to purchase raw materials due to depletion of natural rocks, and environment is disrupted by indiscreet collection of natural rocks.

[4] Accordingly, imitation stones have been conceived to substitute for natural rocks. A conventional imitation stone is manufactured by kneading Portland cement or white cement using water, adding powder and pieces of granite or marble as seed stone materials and loess or Bengala (red oxide of iron) as a pigment to the kneaded cement, and molding the mixture into a plate shape. However, the imitation stone has problems in that a construction process thereof is cumbersome, the imitation stone is often cracked and broken due to external impact or vibration, it is difficult to perform construction operations due to frequent separation thereof from a target surface, and the like.

[5] Furthermore, there is a problem in that the conventional imitation stone absorbs moisture and thus is stained with oxides of iron contained in the material of the imitation stone.

[6] Meanwhile, in a case where a general ceramic tile is used as outdoor flooring for stairs and the like, there are problems in that aesthetic appearance of the ceramic tile is deteriorated since a glaze-treated portion of the ceramic tile is damaged by walking or the like thereon, and in that to prevent a bending phenomenon and the like during baking thereof, the ceramic tile cannot be manufactured to conform to the size of the stairs.

[7]

Disclosure of Invention Technical Problem

[8] Accordingly, the present invention is conceived to solve the aforementioned problems. An object of the present invention is to provide a glaze-free imitation stone tile (which is not subjected to glaze treatment) that is manufactured by mixing natural rocks with clay, removing iron from the mixture twice, press-molding the iron- removed mixture at a pressure of 300kgf/cm or more, and baking the press-molded material at a temperature of l,220°C or more so that the stone tile cannot be discolored and deformed and give a feeling of a natural stone material, and a manufacturing method thereof.

[9]

Technical Solution

[10] A glaze-free stone tile according to the present invention for achieving the object is manufactured by blending 65 to 75 weight parts of natural rock and 25 to 35 weight parts of clay as raw materials with each other, finely pulverizing the blended raw materials by a wet type crusher, spray-drying the pulverized raw materials, removing iron from the pulverized raw materials using magnetic rollers before and after the drying, press-molding the iron-removed raw materials into a molded product in the form of a tile at a pressure of 300 to 400kgf/cm , and baking the molded product at a temperature of 1,200 to l,350°C.

[11] Meanwhile, a method of manufacturing a glaze-free stone tile according to the present invention for achieving the object comprises the steps of (a) blending 65 to 75 weight parts of natural rock and 25 to 35 weight parts of clay as raw materials with each other; (b) finely pulverizing the raw materials blended in step (a) by a wet type pulverizer; (c) removing iron from the raw materials pulverized in step (b); (d) spray- drying the iron-removed raw materials obtained in step (c); (e) removing iron from the raw materials dried in step (d); (f) mixing the iron-removed raw materials obtained in step (e) using a mixer; (g) molding the mixed raw materials into a molded product in the form of a tile by applying a pressure of 300 to 400kgf/cm to the raw materials mixed in step (f) by means of a press; and (h) heating the molded product obtained in step (g) to a temperature of 1,200 to l,350°C.

[12] Preferably, steps (c) and (e) are performed by removing iron from the raw materials using magnetic rollers.

[13] The natural rock may comprise 20 to 30 weight parts of feldspar, 20 to 25 weight parts of pottery stone, 20 to 25 weight parts of agalmatolite, 1.5 to 1.9 weight parts of mica, and 0.1 to 0.5 weight parts of pigment in a total of 100 weight parts of the raw materials.

[14] Step (d) may be performed by spray-drying the raw materials using a spray dryer such that the raw materials contain 2 to 5 weight parts of moisture. [15] Preferably, the method further comprises the step of aging the raw materials by storing the iron-removed raw materials obtained in step (e) in a silo tank so that the raw materials can be better mixed after the blending. [16] The molded product obtained in step (g) preferably has a thickness of 1.3cm to

2.0cm. [17]

Advantageous Effects

[18] With the manufacturing method of the glaze-free stone tile according to the present invention, there is provided a stone tile which has superior waterproof property, high strength, and an absorbency of 1% or less in a finished product even though it is not subjected to glaze treatment, and can prevent discoloration generated due to oxidation of iron contained in the finished product, so that the stone tile can be used as construction materials by substituting for a natural rock.

[19] Furthermore, since the glaze-free stone tile of the present invention can be molded to have a size applicable to stairs of apartments and the like, it can substitute for natural stone.

[20]

Brief Description of the Drawings

[21] Fig. 1 is a flowchart illustrating a stone tile manufacturing process according to the present invention.

[22] Fig. 2 is a view showing an iron removal process of Fig. 1.

[23]

[24] **Explanation of reference numerals for designating main components in the drawings**

[25] 10: Raw material powder 20: Conveyor belt

[26] 30: Magnetic roller

[27]

Best Mode for Carrying Out the Invention

[28] A plurality of embodiments of the present invention may exist, and a preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings. The object, features and advantages of the present invention will be better understood from the preferred embodiment.

[29]

[30] Fig. 1 is a flowchart schematically illustrating a manufacturing process of a glaze- free stone tile according to an embodiment of the present invention, and Fig. 2 is a view schematically showing an iron removal process. [31]

[32] A general ceramic tile is manufactured through a glazing process of applying glaze to a base material of the ceramic tile and baking the glaze-applied material, resulting in increased strength and absorbency removal. On the contrary, a glaze-free stone tile of the present invention can satisfy requirements for surface strength and absorbency even without the glazing process.

[33] As illustrated in Fig. 1, the glaze-free stone tile of the present invention is manufactured through a blending process, a pulverizing process, a first iron-removal process, a drying process, a second iron-removal process, an aging process, a mixing process, a molding process, a cleaning process, and a blast furnace processing process.

[34] First, the blending process (S 10) is a process of blending raw materials of a stone tile, in which clay such as kaolin is blended with a natural rock such as feldspar, pottery stone, agalmatolite and mica at a blending ratio of raw materials.

[35] In case of a ceramic tile, 10 to 20 weight parts of clay in total weight is generally blended, while in case of a glaze-free stone tile of the present invention, 25 to 35 weight parts of clay in total weight is blended. Although increase in the content ratio of the clay prolongs heating time to cause a disadvantage of increased manufacturing costs, it enhances cohesive force. Thus, the blending ratio of the clay is increased by 15 weight parts as compared with a general ceramic tile.

[36] According to the content ratio of the clay, 65 to 75 weight parts of natural rock in total weight is blended. The composition of the clay and the natural rock is as follows. That is, assuming that total weight is 100, the composition preferably comprises 20 to 30 weight parts of feldspar, 20 to 25 weight parts of pottery stone, 20 to 25 weight parts of agalmatolite, 25 to 35 weight parts of clay (kaolin) and 1.5 to 1.9 weight parts of mica. The composition preferably comprises 0.1 to 0.5 weight parts of pigment to impart a color to a completed tile. Clay gives plasticity to the tile, pottery stones function to adjust baking shrinkage and refractoriness, and feldspars are molten to become a strong melt during heating and is not crystallized but remains in a free state during cooling so that the feldspars can enter grain boundaries between crystal grains of a sintered body to remove pores and to function as a binder.

[37] The raw material pulverizing process (S20) is performed by pulverizing the raw materials using a wet type pulverizer such as a ball mill in order to finely pulverize the blended raw materials according to the purpose of use thereof. In case of a conventional glazed ceramic tile, pulverization is performed to obtain a particle size of about 220 to 230 mesh, while in case of the glaze-free stone tile of the present invention, pulverization is performed to obtain a particle size of about 300 to 320 mesh, thereby showing the texture of a natural stone.

[38] The first iron-removal process (S30) is performed by primarily removing iron from the finely pulverized raw materials using magnetic rollers. As shown in Fig. 2, while a conveyor belt 30 for transferring raw materials 10 that are pulverized and come out of the ball mill passes above magnetic rollers 20, iron contained in the raw materials 10 is separated from powder of the raw materials 10 by magnetic forces of the magnetic rollers 20. Since the raw materials have been pulverized through the wet type pulverizing process, the raw materials that have passed through the ball mill are in a state where particles of the rock and clay are dispersed in liquid. Therefore, iron particles are separated from the raw materials when the conveyor belt passes above the magnetic rollers.

[39] The drying process (S40) is a process of drying the iron-removed raw materials through spray nozzles by using a spray dryer so that the iron-removed raw materials have a moisture content and a particle size required in the molding process. At this time, the raw materials are preferably dried such that the raw materials contain about 2 to 5 weight parts of moisture.

[40] The second iron-removal process (S50) is a process of sufficiently removing iron from the dried powder-like raw materials by passing a conveyor belt for transferring the dried powder-like raw materials above magnetic rollers 20 to remove iron from the raw materials once again. Though the iron-removal processes before and after the drying process, iron is completely removed from the raw materials, thereby preventing discoloration in a finished product, which may be produced if iron is contained in a finished product.

[41] The aging process (S60) is a process of aging the raw materials by storing the raw materials in a silo tank or the like so that the raw materials can be better mixed after the blending.

[42] The mixing process (S70) is a process of mixing the aged raw materials using a mixer or the like.

[43] The molding process (S80) is a process of molding the raw materials into a tile with a desired shape by inputting the mixed raw materials into a mold and applying a pressure of 300 to 400kgf/cm to the raw materials. That is, the aged raw materials are input into a cavity defined in the mold, the mold arranged with an area of 4,000 to 4,800cm is pressed by a press arm of 1,500 to 1,800 tons. The raw materials that have received a pressure of about 300 to 400kgf/cm are molded to conform to the shape of the cavity defined in the mold. This is a process of forming the raw materials composed through the aforementioned processes (SlO to S70) into a tile with a desired shape and is performed by means of press molding or compression molding in which the raw materials are pressed into a tile with a designed shape by using a mold. The press-molded product is formed to have a thickness of 1.3 to 2.0cm, thereby preventing the molded product from being bent or distorted in a baking process at high temperature. If the molded product has a thickness smaller than the range of thickness, there is a problem in that the molded product may be distorted during the baking process. Since the molding process is performed using a press at a high pressure of 300kgf/cm or more, air can be sufficiently vented outside the raw materials, thereby forming a molded-product with a uniform and high filling density, a low moisture content, and stickiness. Furthermore, baking shrinkage and absorbency of a molded product can be reduced at the same time.

[44] The cleaning process (S90) is a process of removing impurities from the molded product through cleaning prior to baking thereof.

[45] The baking process (SlOO) is a process of imparting strength by baking the molded product. The molded product is baked while being passed through a blast furnace rail at a high temperature of 1,200 to l,350°C. Since the molded product does not have its own strength at a temperature of less than l,220°C, it is desirable to bake the molded product at a temperature of l,220°C or more. Since stone is molten during the baking process, natural beauty is expressed on the surface of a finished product. Although a conventional stone tile is subjected to a glazing process, the glaze-free stone tile of the present invention does not undergo glaze treatment and thus requires higher wear resistance, higher chemical resistance and the like. Therefore, it is preferred that the glaze-free stone tile be baked at temperature higher than that in the conventional stone tile. A conventional glazed tile undergoes heat treatment at a temperature of 1,100 to l,150°C, and has a problem in that upon heating thereof at a temperature of l,200°C, the conventional glazed tile is distorted during baking if the thickness thereof is 1.5cm or less. However, since a molded product obtained according to the present invention has a high filling density while passing through the pressing process using a press at high pressure, the molded product can be molded to have a thickness of 1.5cm or less and can be baked at a temperature of l,200°C or more.

[46] Since stone is molten during the baking process upon manufacture of the stone tile according to the present invention, the texture of a natural stone or granite is formed on the surface of the stone tile, and a finished stone tile product has high compression strength, a low surface wear rate and a low absorbency of 0.1% or less.

[47]

[48] <Example 1>

[49] Raw materials were blended at a blending ratio of 24 weight parts of feldspar, 23 weight parts of pottery stone, 23 weight parts of agalmatolite, 28 weight parts of kaolin, 0.2 weight parts of pigment and 1.8 weight parts of mica, and the blended raw materials were finely pulverized using a ball mill. The finely pulverized raw materials were passed above magnetic rollers 20 to primarily remove iron. The iron-removed raw materials were dried using a spray dryer such that they contain about 2 to 5 weight parts of moisture. The dried raw materials were passed above the magnetic rollers 20 again to secondarily remove iron therefrom, and the iron-removed raw materials were stored and aged in a silo tank. The aged raw materials were mixed using a mixer and then input into a cavity of a mold to form them into a tile. The mold was arranged with an area of 4,000cm , and then pressed by a press arm of 1,600 tons so as to apply a pressure of 400kgf/cm . The mold was designed to allow a molded product to have a thickness of 1.5cm, a length of 60cm and a width of 35cm, and the molded product was subjected to a cleaning process to remove impurities and was then baked. The molded product was subjected to the baking process by being baked at a baking temperature of l,220°C. Test results are shown in Table 1 below.

[50] Table 1

[51] [52] As can be seen from the results shown in Table 1, which are test results of Korea Institute of Construction Materials on July 15, 2005, contrary to conventional stone tile, a glaze-free stone tile of the present invention is press-molded at a pressure of 350kgf/cm , can be formed to have a thickness of 15mm or less even though baking is performed at a temperature of l,220°C, and does not suffer from a distortion phenomenon during baking even though it is molded to have a size larger than 60cm in length and 34cm in width. That is, although the conventional tile has been manufactured to have a specification of 15cm x 15cm due to a distortion phenomenon, the glaze-free stone tile of the present invention can be manufactured to have a size larger than 60cm x 34cm with a thickness of 13mm while a distortion phenomenon does not occur during baking and a bending strength can be maintained above a reference value. Therefore, the glaze-free stone tile of the present invention can substitute for conventional stone in stairs of apartments and the like.

[53] Since the glaze-free stone tile of the present invention is baked at a high temperature of l,200°C or more, it has a low moisture absorbency of 0.1% or less without glazing treatment that is commonly performed for general tiles. Thus, damage due to moisture absorption can be prevented.

[54] Furthermore, since the stone tile of the present invention undergoes the iron- removal process twice as described above, it solves the problem of discoloration in a finished product due to oxidation of iron contained in the product after the product is used for construction, and shows good properties beyond Korean Standard values in view of all items including bending strength, absorbency, wear resistance, crack resistance, chemical resistance and frost resistance.

[55] The glaze-free stone tile of the present invention can substitute for a natural rock and be used for construction of indoor and outdoor stairs, indoor and outdoor wall surfaces and floors of buildings as well as flooring of outdoor parking lots.

[56]

Industrial Applicability

[57] As described above in detail, a manufacturing method of a glaze-free stone tile according to the present invention provides a stone tile which has superior waterproof property, high strength, and an absorbency of 1% or less in a finished product even though it is not subjected to glaze treatment, and can prevent discoloration generated due to oxidation of iron contained in the finished product, so that the stone tile can be used as construction materials by substituting for a natural rock.

[58] Furthermore, since the glaze-free stone tile of the present invention can be molded to have a size applicable to stairs of apartments and the like, it can substitute for natural stone.

[59]

[60]

Claims

[1] A method of manufacturing a glaze-free stone tile, comprising the steps of:

(a) blending 65 to 75 weight parts of natural rock and 25 to 35 weight parts of clay as raw materials with each other;

(b) finely pulverizing the raw materials blended in step (a) by a wet type pulverizer;

(c) removing iron from the raw materials pulverized in step (b);

(d) spray-drying the iron-removed raw materials obtained in step (c);

(e) removing iron from the raw materials dried in step (d);

(f) mixing the iron-removed raw materials obtained in step (e) using a mixer;

(g) molding the mixed raw materials into a molded product in the form of a tile by applying a pressure of 300 to 400kgf/cm to the raw materials mixed in step

(f) by means of a press; and

(h) heating the molded product obtained in step (g) to a temperature of 1,200 to l,350°C.

[2] The method as claimed in claim 1, wherein steps (c) and (e) are performed by removing iron from the raw materials using magnetic rollers.

[3] The method as claimed in claim 1, wherein the natural rock comprises feldspar, pottery stone, agalmatolite and mica.

[4] The method as claimed in claim 1, wherein the raw materials comprises 20 to 30 weight parts of feldspar, 20 to 25 weight parts of pottery stone, 20 to 25 weight parts of agalmatolite, 25 to 35 weight parts of kaolin, 1.5 to 1.9 weight parts of mica, and 0.1 to 0.

5 weight parts of pigment. [5] The method as claimed in claim 1, wherein step (d) is performed by spray-drying the raw materials using a spray dryer such that the raw materials contain 2 to 5 weight parts of moisture.

[6] The method as claimed in claim 1, further comprising the step of aging the raw materials by storing the iron-removed raw materials obtained in step (e) in a silo tank so that the raw materials can be better mixed after the blending.

[7] The method as claimed in claim 1, wherein the molded product obtained in step

(g) has a thickness of 1.3cm to 2.0cm.

[8] The method as claimed in claim 1, wherein the fine pulverization of step (b) is performed to obtain a particle size of 300 to 320 mesh. [9] A glaze-free stone tile manufactured by a method according to any one of claims

I to 8.