WO1998011033A1

WO1998011033A1 - The process of manufacturing ceramics using wastes

Info

Publication number: WO1998011033A1
Application number: PCT/KR1997/000172
Authority: WO
Inventors: Se-Lin Lee
Original assignee: Lee Se Lin
Priority date: 1996-09-16
Filing date: 1997-09-13
Publication date: 1998-03-19
Also published as: KR100237349B1; KR19980024175A; AU4400897A

Abstract

The present invention provides the process of manufacturing ceramics using coal ashes and all sort of wastes (Process I). Also, the present invention provides the process of manufacturing permeable ceramics by forming pores into the ceramic structure by further process following Process I (Process II). Furthermore, the present invention provides the process of manufacturing ceramics from 100 % coal ashes only (Process III). The process in accordance with the present invention basically comprises incinerating wastes, admixing, press-molding, and sintering.

Description

THE PROCESS OF MANUFACTURING CERAMICS USING WASTES

Technical Field

The present invention relates to manufacturing ceramics using wastes, and in particularly the ceramics not only having an identical quality with the others manufactured from the general raw materials but also overcome the existing problems prior art have.

Background Art

Up to now, most of the general wastes excluding recyclables are buried or the ashes of burn up are buried without any practical usage, which has been causing a serious environmental contamination and the shortage of landfill problems.

The study of recycling coal ashes to cements, bricks and light construction raw materials has been carried out, but the consumption of recycling coal ashes is less than 10% of the total coal ashes occurring and rest of the coal ashes are filled in seashore.

Also the product of admixed coal ashes and cements is having problems like, when they are eroded for 5-10 years due to the reaction of acidic and alkalic component, toxic products to human such as sulfur compounds may occur.

Ceramics, a generic term of non-metallic inorganic compound generally the utility enhanced by high thermal treatment, are applied in many field of industries such as tiles, porcelain, bricks, paving, grinding stone in building construction, cornerstone, boundary stone and light construction raw materials.

A typical prior art of manufacturing ceramics is carried out by the process of press-molding and sintering at high temperature of the admixing powder constitute more than 12— 17 different component such as feldspar, pottery stone, loess, clay and dolomite.

Such a process of prior art have required many different sort of raw materials to be supplied in time and had a complex manufacturing process, which have been indicated as a disadvantage in production cost side when compared with concrete or cement usually used in construction materials, bricks and pavings.

Since bricks and pavings are generally made of cement, it is also disadvantageous that they are heavy to handle in construction and not strong enough to stand for a long period, (for example, pavings need to be replaced for 3-5 years)

Also the ceramics manufactured by prior art are not having a permeability therefore, unsuitable to use where the permeability is required, like pavings.

It is therefore an object of the present invention to provide the ceramics manufactured from ashes of wastes, and contribute the environmental conservation by the substitution of natural resources it is another object of the present invention to provide non-toxic products, ceramics from wastes by the process of sintering at high temperature wherein the toxic sulfur compound is removed and fully sterilized.

It is another object of the present invention to provide a ceramics made of wastes which having a identical quality with the others made by general raw materials, furthermore overcome the disadvantages of prior art such as no permeability and high production cost.

It is also another object of the present invention to provide a ceramics improved in appearance, lighter in weight and more solid, which will substitute for existing construction materials such as cements and concretes.

Disclosure of Invention

In accordance with the present invention, the serial process of manufacturing ceramics includes incinerating wastes to ashes, adding silicates mixture with the ashes, press-molding and sintering process( hereinafter referred to as 'Process I'): supplementary process is carried out further on the ceramics prepared in accordance with Process I to manufacture permeable ceramics (hereinafter referred to as 'Process II'); the process of using lOOse ashes only for manufacturing ceramics (hereinafter referred to as 'Process III ' ) Detai led each process is expl ained in the fol l owing.

Process I

Process I comprises, (i) incinerating wastes to obtain fine powder of ashes; (ii) admixing the ashes with the silicates mixture which mainly contains sodium silicate; (iii) press-molding process by using hydraulic molding press; and (iv) sintering process to manufacture ceramics. Detailed each step of the process is given as below.

(i) Wastes Incineration

Fine powder of ashes are prepared from the complete incineration of wastes. Coal ashes (usually from thermal power plant), domestic wastes, industrial wastes, sewage wastes and all sort of wastes can be used as a raw material of ceramics. The waste for using as a raw materials should be complete burned up to form into fine particle of ashes.

(ii) admixing with silicates mixture

The silicates mixture contains mainly sodium silicate(more than 50%), small portion of pottery stone and glass is added to the ashes and well admi ed.

The silicates mixture containing sodium silicate, pottery stone and glass is worked as a binder, especially through the sintering process at thermal condition (higher than 1100'C). sodium silicate is melted and consolidate the binding between ashes while reforming.

From the silicates mixture, finely grinded pottery stone having more than

300 meshes of particle is used. Not like a normal round shapes of stone particle, such a particle having undulated appearance provides the strong binding effect.

Glass is also melted and consolidate the binding between ashes when reforming during the sintering process.

In the mixture, pigment of preferred colour can be admixed additionally to produce the variety colours of ceramics.

The ratio of adding 3 —10 parts by weight of the silicates mixture in 100 parts by weight of ashes is preferred.

Also clay and feldspar can be admixed in ashes(i) besides said mixture to produce variety sort of ceramic product. Adding ratio can be adjusted depond on the product required and preferred adding ratio in 100 parts by weight of the ashes is 10-30 parts by the weight of the clay, 5-20 parts by the weight of the feldspar respectively.

Furthermore, kaolin, talc can be admixed for the variety. Admixing is carried out throughoutly by using proper mixer.

(iii) press-molding

The admixture of ashes and silicates mixture is placed in the mold and pressed within the range betrween 400~~2000kgf/cm of pressure by using hydraulic molding press.

Different shape of the mold is selected depend on the product to be manufactured such as tiles, porcelain, bricks, pavings, grinding stone in building construction and cornerstones.

The pressure of the press-molding is also varied depend on ceramic products, usually thin ceramic such as tile is pressed at 400kgf/cm², paving is pressed at lOOOkgf/cm , thick ceramic such as cornerstone is pressed at 2000kgf/cm of high pressure.

The said ceramic paving pressed as above will normally possess about

220kgf/cm of compression strength when normal concrete and red bricks have about 80kgf/cm , lOkgf/cm of compression strength respectively.

(iv) sintering

Expected ceramic is manufactured finally after aforementioned mold is sintered for 3~4 hours in the sintering kiln at the temperature of 1100 -1400TJ. Preferred sintering temperature range is 1160~1280'C for 3 —4 hours.

Process II

To manufacture permeable ceramics, (v) Crushing ceramics obtained from Process I to small particle, then admixing with prescribed silicates mixture; (vi) press molding process by using hydraulic molding press; and (vii) sintering process is carried out additionally following the aforementioned serial process (i) to (iv).

However, uniform mold can be used in process (iii) of Process II regardless of the final product. Consequently, process (i) to (iv) is carried out to manufacture the ceramics which is not required to be permeable and additional process (v) to (vii) is further carried out to manufacture the permeable ceramics. Ceramics carrying an excellent permeability is prepared as numerous fine pores are formed during the additional process of (v) to (vii) Detailed each step of the additional process is given as below.

(v) admixing sodium silicate with the crushed ceramic

The ceramic prepared by aforementioned process (i) to (iv) is crushed, then admixed with prescribed silicates mixture. The size of crushed particle will vary the size of pores formed inside the structure of permeable ceramic. Although higher permeability will be obtained from larger particle size, particle size is adjusted within less than 10mm depend on permeability requirement since over-large particle size is not suitable for strong binding and desirable appearance.

Prescribed silicates mixture is identical with the one used in process (ii), which contains mainly sodium silicate(more than 50%), small portion of pottery stone and glass, and served as a binder as described before. The preferable adding ratio is 3 —10 parts by weight of the silicates mixture in 100 parts by weight of the crushed ceramic.

(vi ) press-molding

In accordance with the process (v), the admixture of ceramic particle and the silicates mixture is positioned in the mold and pressed within the range of 1000—2000kgf/cm by using hydraulic molding press The mold is selected depend on the product to be manufactured such as tiles, porcelain, bricks, pavings, grinding stone in building construction and cornerstones.

(vii ) sintering

Expected ceramic is manufactured finally after aforementioned mold is sintered for 3 —4 hours in the sintering kiln at temperature of 1100— 1400TJ. Most preferred sintering temperature range is between 1160 — 1280 TJ for 3 —4 hours. Process III

The process of using 100% ashes only for manufacturing ceramics comprising, (a) crushing coal ashes to fine powder; (b) admixing 100 parts by weight of crushed coal ashes with 8 — 11 parts by weight of water; (c) press-molding process by using hydraulic molding press; and (iv) sintering process at 1200—1240'C. Detailed each step of the process is given as below.

(a) crushing coal ashes

Completely burned coal ashes are crushed to fine powder. As a wastes source, coal ashes are only used in Process III.

(b) mixing with water

Fine powder, 100 parts by weight, prepared in process (a) is completely mixed with 3—10 parts by weight of water. It is recommended to use high spinning disc mixer to bring the complete agitation.

(c) press-molding

The admixture of coal ashes containing moisture prepared by process (b)

' 7 is pressed at pressure higher than I200kgf/cm by using hydraulic molding press.

(d) sintering

The mold prepared by process (c) is sintered for 3—4 hours at temperature of 1200-1240J in the kiln.

The ceramics manufactured by the Process I to 111 have an identical quality with the others manufactured from the general raw materials and can be used in many field of industries such as tiles, porcelain, bricks, paving, grinding stone in building industry, cornerstone, boundary stone and light construction raw materials.

Furthermore, the advantages of . the present invention is that the production cost of the ceramics, especially of Process III, is much reduced when compared with the prior art, more than 1.7 times stronger than normal cement construction materials, more than 1.5 times stronger than normal stone materials and the specific gravity is less than 30% than normal cement materials, which provide much easier construction work.

The production can be diversified by using various addition such as pigments, clay, feldspar, kaolin and talc during the manufacturing Process I or II.

Brief Description of Drawings

The nature and mode of operation of preferred embodiments of the present invention will now be fully described in the following detailed description, taken with the accompanying drawings wherein:

Figure 1 is a block diagram of the manufacturing ceramics in accordance with the Process I of the present invention;

Figure 2 is a block diagram of the manufacturing ceramics in accordance with the Process II of the present invention; and

Figure 3 is a block diagram of the manufacturing ceramics in accordance with the Process III of the present invention.

Best Mode for Carrying out the Invention

Example 1 - manufacturing ceramic brick from wastes

General wastes were burned up and lOOOg of fine particle of ashes were prepared, then admixed with 60g of silicates mixture (sodium silicate 50g + 5g of pottery stone grinded more 300 meshes + glass 5g) by using mixer. The admixture was placed into the brick mold and pressed with lOOOkgf/cm of pressure by using hydraulic molding press. Ceramic brick was obtained after sintered for 3 hours at 1200TJ in the kiln

Example Z - manufacturing ceramic cornerstone from wastes

General wastes were burned up and lOOOg of fine particle of ashes were prepared, then admixed with 60g of silicates mixture (sodium silicate 50g + 5g of pottery stone grinded more 300 meshes + glass 5g), clay 200g, feldspar lOOg by using mixer. The admixture was placed into the brick mold and pressed with lOOOkgf/cm of pressure by using hydraulic molding press. Ceramics brick was obtained after sintered for 3 hours at 1240'C in the ki ln.

Example 3: manufacturing ceramic cornerstone from wastes

General wastes were burned up and lOOOg of fine particle of ashes were prepared, then admixed with the 70g of silicates mixture (sodium silicate 60g + 5g of pottery stone grinded more 300 meshes + glass 5g), feldspar 200g by using mixer. The admixture was placed into the cornerstone mold and pressed with 2000kgf/cm of pressure by using hydraulic molding press. Ceramics cornerstone was obtained after sintered for 4 hours at 1280J in the kiln.

Example 4 '- manufacturing permeable ceramic tile from wastes

General wastes were burned up and lOOOg of fine particle of ashes were prepared, then admixed with the 60g of silicates mixture (sodium silicate 50g + 5g of pottery stone grinded more 300 meshes + glass 5g), clay 200g, feldspar lOOg by using mixer. The admixture was placed into the mold and pressed with 400kgf/cm of pressure by using hydraulic molding press, then sintered for 3 hours at 1280'C in the kiln. The product was crushed into 3mm in the crusher, thereafter lOOg of the crushed ceramic particle was admixed with 60g of the said silicates mixture again, then placed into the tile mold and pressed with 500kgf/cm of pressure by using hydraulic molding press. Permeable ceramics tile was obtained after sintered for 3 hours at 1280VJ in the kiln.

Example 5- manufacturing permeable ceramic paving brick from wastes

General wastes were burned up and lOOOg of fine particle of ashes were prepared, then well admixed with the 70g of silicates mixture (sodium silicate 60g + 5g of pottery stone grinded more 300 meshes + glass 5g), clay 300g by using mixer. The admixture was placed into the mold and pressed with lOOOkgf/cm of pressure by using hydraulic molding press, then sintered for 3 hours at 1280TJ in the kiln. The product was crushed into 4mm in the crusher, thereafter lOOg of the crushed ceramic particle was admixed with 70g of the said silicates mixture again, then placed into the paving brick mold and pressed with 1200kgf/cm of pressure by using hydraulic molding press. Permeable ceramics paving brick was obtained after sintered for 3 hours at 1280TJ in the kiln. Example 6: manufacturing ceramic brick by using 100% wastes only

Completely burned coal ashes were crushed and lOOOg of fine particle of ashes were prepared, then well admixed with water lOOg by using high spinning disc mixer. The admixture was placed into the brick mold and pressed with 1200kgf/cm of pressure by using hydraulic molding press. Ceramic brick was obtained after sintered for 3 hours at 1240TJ in the kiln.

Example ! '• Compression strength comparison

The Compression strength of the ceramics manufactured by following the aforementioned examples was tested by the method of Korean Standard KSF4004-95 and the result was illustrated as below on table 1

TABLE 1

Tested materials Compression strength

Example 1 242 ks /

Example 2 205 kgf/cπr

Example 3 249 kgf/cm"

Example 4 194 kgf/cm"

Example 5 203 kgf/cm"

Example 6 240 kgf/cπr

The result was clearly shown that the ceramics prepared in accordance with the present invention were superior to the normal cement bricks (about 80kgf/cm²) in compression strength.

Example 8- Permeability comparison

The Permeability of the ceramics manufactured by following the aforementioned example 4 & 5 was tested by the method of Korean Standard KSF4004-95 and the result was illustrated as below on table 2

TABLE 2

Tested materials Permeability (%)

Example 4 24

Example 5 26

The result was clearly shown that the ceramics prepared in accordance with the present invention were superior to the normal cement bricks (about 10%) in permeability

Therefore, the present invention would contribute the environmental conservation by recycling the wastes and provide non-toxic recycled ceramics from the process of sintering at high thermal wherein the toxic compounds is removed and fully sterilized.

Furthermore, the production cost of the ceramics, especially 100% wastes used in Process III, is much reduced when compared with the prior art and still maintaining identical quality by reducing the number raw materials and their cost.

Accordingly, the ceramics manufactured in accordance with the present invention is lighter in weight, better in appearance and more solid, which will substitute for existing construction materials.

The present invention will provide the permeable ceramics by additional process for the industry where the permeable ceramics such as paving bricks are required

This invention may be embodies in other specific forms without departing from the spirit or essential characteristic thereof. The present exemples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which become within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

What is Claimed is;

1. The process of manufacturing ceramics using wastes which comprises; (i) incinerating wastes completely to obtain fine powder of ashes;

(ii) admixing 100 parts by weight of the ashes with 3—10 parts by weight of the silicates mixture which contains more than 50% of sodium silicate, small amount of pottery stone and glass;

(iii) putting the admixture of the ashes into the mold then press-molding within the range between 400—2000kgf/cm² of pressure by using hydraulic molding press; and

(iv) sintering the said mold for 3 —4 hours at 1100 — 1400'C in the kiln.

2. The process of claim 1, wherein the sintering is conducted for 3—4 hours at 1160-1280TJ.

3. The process of claim 1, wherein the admixture( ii ) additionally employ 10—30 parts by weight of the clay and/or 5—20 parts by weight of the feldspar in 100 parts by weight of the ashes.

4. The process of manufacturing permeable ceramics using wastes which comprises;

(i) incinerating wastes completely to obtain fine powder of ashes;

(ii) admixing 100 parts by weight of the ashes with 3 —10 parts by weight of the silicates mixture which contains more than 50% of sodium silicate and small amount of pottery stone and glass ;

(iii) putting the admixture of the said ashes in the mold then press the molding within the range between 400~2000kgf/cm of pressure by using hydraulic molding press;

(iv) sintering the said mold for 3—4 hours at 1100 — 1400j in the kiln;

(v) crushing the product obtained from the sintering(iv) to less than

10mm. thereafter admixing 100 parts by weight of the crushed particle with 3 —10 parts by weight of said silicates mixture of (ii);

(vi) putting the admixture of the ceramics and silicates mixture into the mold then press-molding within the range between 1000—2000kgf/cm² of pressure by using hydraulic molding press; and

(vii) sintering the said mold for 3 —4 hours at 1100 — 1400TJ in the kiln;

5. The process of claim 4, wherein the sintering is conducted for 3 —4 hours at H60~1280t.

6. The process of claim 4, wherein the admixing(ii) additionally employ 10—30 parts by weight of the clay and/or 5 —20 parts by weight of the feldspar in 100 parts by weight of the ashes.

7. The process of manufacturing ceramics using 100% wastes only which comprises;

(a) crushing completely burned coal ashes to obtain fine powder of the ashes;

(b) mixing 100 parts by weight of the ashes(a) with 8 — 11 parts by weight of water and mixing throughout by using high spinning disc mixer;

(c) putting the admixture containing moisture into the mold then press-molding at 1200kgf/cm of pressure by using hydraulic molding press; and

(d) sintering the said mold(c) for 3-4 hours at 1200-1240TJ in the kiln.