CA1129183A - Brick making - Google Patents
Brick makingInfo
- Publication number
- CA1129183A CA1129183A CA352,213A CA352213A CA1129183A CA 1129183 A CA1129183 A CA 1129183A CA 352213 A CA352213 A CA 352213A CA 1129183 A CA1129183 A CA 1129183A
- Authority
- CA
- Canada
- Prior art keywords
- weight
- clay
- powdered glass
- brick
- based body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B33/00—Clay-wares
- C04B33/02—Preparing or treating the raw materials individually or as batches
- C04B33/13—Compounding ingredients
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Dispersion Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In a method of making brick wherein a clay-based body is formed to a desired shape and subsequently kiln burned to maturity, the improvement comprising intimately admixing powdered glass in an amount in the range of about 0.25 to about 12.5% by weight with said clay-based body prior to said step of forming. The powdered glass typically has a particle size of about -65 mesh or less. The invention provides a kiln burned brick of increased compressive strength, decreased water absorption and lowered apparent specific gravity, relative to a kiln burned brick lacking powdered glass intimately admixed with the clay-based body from which it is produced.
In a method of making brick wherein a clay-based body is formed to a desired shape and subsequently kiln burned to maturity, the improvement comprising intimately admixing powdered glass in an amount in the range of about 0.25 to about 12.5% by weight with said clay-based body prior to said step of forming. The powdered glass typically has a particle size of about -65 mesh or less. The invention provides a kiln burned brick of increased compressive strength, decreased water absorption and lowered apparent specific gravity, relative to a kiln burned brick lacking powdered glass intimately admixed with the clay-based body from which it is produced.
Description
1~29183 The present invention relates to an improvement in brick making.
More specifically, the present invention relates to the addition of specified amounts of a synthetic prefired flux material, namely powdered glass, to a clay-based body prior to forming and kiln burning to maturity to yield a brick of increased compressive strength, decreased water absorption and lowered apparent specific gravity, relative to a kiln burned brick lacking powdered glass in the clay-based body from which it is produced.
The present invention is particularly useful in the production of the lightweight GIANT~ through-the-wall bricks disclosed and claimed in Canadian Patent No. 986,288, issued March 30, 1976, and in the water passage resistant DRILINE~ bricks disclosed and claimed in Canadian Patent No.
962,852, issued February 18, 1975.
While the lightweight GIANT~ through-the-wall bricks are conventionally produced by the dry press process, the present invention is generally applicable to all burned clay products, including those produced by the stiff mud process.
Market acceptance of burned clay bricks depends largely upon two factors. First, the burned clay colour of the bricks must be aesthetically pleasing. Second, the bricks must satis~y all technical specification requirements of appllcable regulatory bodies, the most important requirement typically being a given minimum compressive strength.
~nlike the stiff mud process, the dry press process of manufacture requires constant and diligent quality control l~Z'g~83 surveillance to ensure ~hat every brick manufactured has adequate end-product strength to satisfy the minimum applicable technical specifications. By way of explanation, in the dry press process compressive strength is proportional to density and density is directly related to applied pressure. It is thus common practice to operate dry press machines at near - maximum pressing capacity to ensure that every brick produced has the required density value to develop adequate end-- product strength when kiln burned to maturity. Despite this, normal variances in composition of the naturally occurring clay and shale components employed in the clay-based body make it impossible to absolutely predict the physical properties of each individual brick manufactured.
The prior art provides two methods of increasing compressive strength of burned clay bricks. First, the addition of a natural fluxing mineral, for example nepheline syenite or feldspar, to the clay-based body. Second, the addition of a ballmilled fraction of the clay itself back into the clay-based body. Both of these methods are well known in the brick industry and both have the same shortcomings, namely that in the dry press process at least a 15% by weight addition is requisite to absolutely guarantee the minimum physical properties of every brick. This is expensive to the point of being uneconomical on a mass production basis. More i~portantly from a market standpoint, such a level of addition drastically alters the burned clay colour of the brick.
The present invention, by the addition of the powdered glass, inexpensively provides sufficient low viscosity ~1/ -2-- ~ ' . ~ ' :, " ~::
highly reactive flux within the clay matrix during kiln burning to afford a significant increase in compressive strength, a lowering of water absorption and a lowering of apparent specific gravity, without a recognizable, or at least unnacceptable, change in colour of the burned clay brick. Thus, while maintaining colour characteristics prerequisite to market acceptance, elaborate and expensive quality control during the manufacturing process can be minimized with assurance that all bricks produced will possess at least a given minimum compressive strength.
Supplementary, but attractive, advantages which can accrue from the present invention include an ability to potentially employ reduced forming pressures in the dry press machines, thereby lowering machine maintenance costs, and an ability to potentially reduce kiln burning temperatures, with attendant energy savings, dependent upon the particular clay-based body employed and the requisite end-product characteristics.
The use of powdered glass in the manufacture of ceramic articles is taught in Canadian Patent No. 968,813, issued June 3, 1975. The patent however teaches the use of from about 25% to 45% by weight of powdered glass, an amount significantly beyond that contemplated or acceptable for use in the present invention, in the manufacture of dense ceramic artlcles such as lamp bases. The patent further teaches, on lines 12/13 of Disclosure Page 9, that the ceramic bodies display a shrinkage of from about 8% to 12% between the pressed and fired states, a shrinkage factor totally unacceptable ~1/ -3-~2~8~
in the brick industry due to a resultant cull rate estimated to run as high as 40% of total production.
Thus, in a broad aspect the present invention pr~vides in a method of making brick wherein a clay-based body is formed to a desired shape and subsequently kiln burned to maturity, the improvement comprising intimately admixing powdered glass in an amount in the range of about 0.25 to about 12.5% by weight with said clay-based body prior to said step of forming.
The preferred powdered glass employed in the pres~nt invention is of the readily available soda-lime silicate type i.e. reclaimed ~aste glass, bottles, plate etc., of the following typical chemical composition, in ~ by weight:
sio260.00 - 80.00 A1203 0.10 - 5.00 Na2O5.00 - 18.00 K 2 ; - : 5-00 Fe203 0 .01 - ; 1.00 MgO0.01 - 5.00 20 CaO3.00 - 15.00 As 23 Optional Trace Amount cr23Optional Trace Amount B203Optional Trace Amount Co304 Optional Trace Amount Sb 2 3 Optional Trace Amount TiO 2 Optional Trace Amount Other low melting point glasses can also be employed, fox example lime and lead glasses.
The glass characterist~cally becomes pyroplastic at about 130QF and begins to form a li~uid melt abo~e about 1400F, bm: ~.
1129~8:~
the ~iscosity of which decreases with increased temperature.
The powdered glass is added to the clay-based body prior to forming and intimately admixed to ensure even - dissemination. Powdered glass of a particle size of about -65 mesh has been found satisfactory.
Since clay-based bodies are typically kiln burned to maturity, subsequent to forming to desired shape, at a temperature in the range of about 1750 to 2400F, that is about 450 to about 1100F above the softening point of the powdered glass, the addition of the powdered glass, even in relatively small amounts, provides increased intermediate strength, due to reaction wi~h the clay matrix, at temperatures where the clay is at its weakest because of break-down of the clay molecule and lack of ceramic bond formation. The use of the powdered glass thus tends to decrease production lc~ssess inithe form of culls during the kiln burning.
The amount of powdered glass intimately admixed with thé clay-based body can range from about 0.25 to about 12.5 % by weight. The upper limit is primarily dictated by the extent of colour degradation acceptable, and will vary somewhat according to thé particular composition of the c~ay-based body. A preferred amount of powdered glass is in the range of from about 0.5 to about 5.0 % by weight.
The clay-based bodies can additionally include an ~au~t of about 5.0 to a~out 80.0% by weight of a particulate shrinkage control agent to reduce green to fired shrinkage to an acceptab~e magnitude, ty-pically to a shrinkage of ab-out a maximum of 3~. The particulate shrinkage control agent is generally one or more members selec-ted from the 3~ yroup consisting of calcined refractory clay, naturally hrn~
9~83 occurring aggregate or sand, calcined non-refrac~ory clay or shale and grog.
In the stiff mud process, an amount of about 5.0 to 65.0% by weight of the shrinkage control agent is typically employed, prefèrably ground to ~4 mesh or finer.
In the dry press process, an amount of about 5.0 to about ~0.0% byweight of the shrinkage control agent is typically employed, preferably ground to -4 mesh or finer.
The advantages of the present invention will become apparent from the following Tables, the tests of which were all conducted in accordance with CSA and ASTM Standard Test Methods.
Table I compares the properties of dry press bricks produced from a control clay-based body, Mix IA, against those of bricks produced from the clay-based body having
More specifically, the present invention relates to the addition of specified amounts of a synthetic prefired flux material, namely powdered glass, to a clay-based body prior to forming and kiln burning to maturity to yield a brick of increased compressive strength, decreased water absorption and lowered apparent specific gravity, relative to a kiln burned brick lacking powdered glass in the clay-based body from which it is produced.
The present invention is particularly useful in the production of the lightweight GIANT~ through-the-wall bricks disclosed and claimed in Canadian Patent No. 986,288, issued March 30, 1976, and in the water passage resistant DRILINE~ bricks disclosed and claimed in Canadian Patent No.
962,852, issued February 18, 1975.
While the lightweight GIANT~ through-the-wall bricks are conventionally produced by the dry press process, the present invention is generally applicable to all burned clay products, including those produced by the stiff mud process.
Market acceptance of burned clay bricks depends largely upon two factors. First, the burned clay colour of the bricks must be aesthetically pleasing. Second, the bricks must satis~y all technical specification requirements of appllcable regulatory bodies, the most important requirement typically being a given minimum compressive strength.
~nlike the stiff mud process, the dry press process of manufacture requires constant and diligent quality control l~Z'g~83 surveillance to ensure ~hat every brick manufactured has adequate end-product strength to satisfy the minimum applicable technical specifications. By way of explanation, in the dry press process compressive strength is proportional to density and density is directly related to applied pressure. It is thus common practice to operate dry press machines at near - maximum pressing capacity to ensure that every brick produced has the required density value to develop adequate end-- product strength when kiln burned to maturity. Despite this, normal variances in composition of the naturally occurring clay and shale components employed in the clay-based body make it impossible to absolutely predict the physical properties of each individual brick manufactured.
The prior art provides two methods of increasing compressive strength of burned clay bricks. First, the addition of a natural fluxing mineral, for example nepheline syenite or feldspar, to the clay-based body. Second, the addition of a ballmilled fraction of the clay itself back into the clay-based body. Both of these methods are well known in the brick industry and both have the same shortcomings, namely that in the dry press process at least a 15% by weight addition is requisite to absolutely guarantee the minimum physical properties of every brick. This is expensive to the point of being uneconomical on a mass production basis. More i~portantly from a market standpoint, such a level of addition drastically alters the burned clay colour of the brick.
The present invention, by the addition of the powdered glass, inexpensively provides sufficient low viscosity ~1/ -2-- ~ ' . ~ ' :, " ~::
highly reactive flux within the clay matrix during kiln burning to afford a significant increase in compressive strength, a lowering of water absorption and a lowering of apparent specific gravity, without a recognizable, or at least unnacceptable, change in colour of the burned clay brick. Thus, while maintaining colour characteristics prerequisite to market acceptance, elaborate and expensive quality control during the manufacturing process can be minimized with assurance that all bricks produced will possess at least a given minimum compressive strength.
Supplementary, but attractive, advantages which can accrue from the present invention include an ability to potentially employ reduced forming pressures in the dry press machines, thereby lowering machine maintenance costs, and an ability to potentially reduce kiln burning temperatures, with attendant energy savings, dependent upon the particular clay-based body employed and the requisite end-product characteristics.
The use of powdered glass in the manufacture of ceramic articles is taught in Canadian Patent No. 968,813, issued June 3, 1975. The patent however teaches the use of from about 25% to 45% by weight of powdered glass, an amount significantly beyond that contemplated or acceptable for use in the present invention, in the manufacture of dense ceramic artlcles such as lamp bases. The patent further teaches, on lines 12/13 of Disclosure Page 9, that the ceramic bodies display a shrinkage of from about 8% to 12% between the pressed and fired states, a shrinkage factor totally unacceptable ~1/ -3-~2~8~
in the brick industry due to a resultant cull rate estimated to run as high as 40% of total production.
Thus, in a broad aspect the present invention pr~vides in a method of making brick wherein a clay-based body is formed to a desired shape and subsequently kiln burned to maturity, the improvement comprising intimately admixing powdered glass in an amount in the range of about 0.25 to about 12.5% by weight with said clay-based body prior to said step of forming.
The preferred powdered glass employed in the pres~nt invention is of the readily available soda-lime silicate type i.e. reclaimed ~aste glass, bottles, plate etc., of the following typical chemical composition, in ~ by weight:
sio260.00 - 80.00 A1203 0.10 - 5.00 Na2O5.00 - 18.00 K 2 ; - : 5-00 Fe203 0 .01 - ; 1.00 MgO0.01 - 5.00 20 CaO3.00 - 15.00 As 23 Optional Trace Amount cr23Optional Trace Amount B203Optional Trace Amount Co304 Optional Trace Amount Sb 2 3 Optional Trace Amount TiO 2 Optional Trace Amount Other low melting point glasses can also be employed, fox example lime and lead glasses.
The glass characterist~cally becomes pyroplastic at about 130QF and begins to form a li~uid melt abo~e about 1400F, bm: ~.
1129~8:~
the ~iscosity of which decreases with increased temperature.
The powdered glass is added to the clay-based body prior to forming and intimately admixed to ensure even - dissemination. Powdered glass of a particle size of about -65 mesh has been found satisfactory.
Since clay-based bodies are typically kiln burned to maturity, subsequent to forming to desired shape, at a temperature in the range of about 1750 to 2400F, that is about 450 to about 1100F above the softening point of the powdered glass, the addition of the powdered glass, even in relatively small amounts, provides increased intermediate strength, due to reaction wi~h the clay matrix, at temperatures where the clay is at its weakest because of break-down of the clay molecule and lack of ceramic bond formation. The use of the powdered glass thus tends to decrease production lc~ssess inithe form of culls during the kiln burning.
The amount of powdered glass intimately admixed with thé clay-based body can range from about 0.25 to about 12.5 % by weight. The upper limit is primarily dictated by the extent of colour degradation acceptable, and will vary somewhat according to thé particular composition of the c~ay-based body. A preferred amount of powdered glass is in the range of from about 0.5 to about 5.0 % by weight.
The clay-based bodies can additionally include an ~au~t of about 5.0 to a~out 80.0% by weight of a particulate shrinkage control agent to reduce green to fired shrinkage to an acceptab~e magnitude, ty-pically to a shrinkage of ab-out a maximum of 3~. The particulate shrinkage control agent is generally one or more members selec-ted from the 3~ yroup consisting of calcined refractory clay, naturally hrn~
9~83 occurring aggregate or sand, calcined non-refrac~ory clay or shale and grog.
In the stiff mud process, an amount of about 5.0 to 65.0% by weight of the shrinkage control agent is typically employed, prefèrably ground to ~4 mesh or finer.
In the dry press process, an amount of about 5.0 to about ~0.0% byweight of the shrinkage control agent is typically employed, preferably ground to -4 mesh or finer.
The advantages of the present invention will become apparent from the following Tables, the tests of which were all conducted in accordance with CSA and ASTM Standard Test Methods.
Table I compares the properties of dry press bricks produced from a control clay-based body, Mix IA, against those of bricks produced from the clay-based body having
2.5% by weight powdered glass added, ~ix IB, and bricks produced from the clay-based body having 5.0% by weight powdered glass added, Mix TC.
brn:)~
llZ9183 TABLE I
Mix, % by weightIA (Control) IB IC
Buff Fireclay 56 56 56 Fireclay 14 14 14 Calcined Fireclay25 25 25 Grog (Buff) 5 5 5 Powdered Glass % by weight Over ~ Above 0.0 2.5 5 Moisture Content as Pressed, % 6.0 6.0 6.0 Forming Pressure, psi 2415 2415 2415 Burning Temperature, F 2290 2290 2290 Modulus of Rupture, psi 1645 2044 2180 Net Area Compressive Strength, psi 8259 10690 13960 Apparent Porosity, % 20.7 18 12.5 Water Absorption, % 10.0 8.6 6.0 Bulk Dengity, pc~142.7 142.0 130.6 Apparent Specific Gravity 2.62 2.55 2.39 Colour Standard Standard Slight Darkening Golden Golden of Golden Buff Buff BuffColour Colour Colour i1/ -7-~lZ9183 It may be noted from Table I that the bricks produced from Mix IB display a significant increase in compressive strength over bricks produced from the Control, and that the bricks produced from Mix IC display an even more marked increase in compressive strength.
It may further be noted from Table I that the bricks produced from Mix IB display a decrease, and the bricks produced from Mix IC a greater decrease, in water absorption over bricks produced from the Control, indicative of increased resistance to penetration and passage of moisture, liquid and vapour through the bricks.
It may additionally be noted from Table I that the bricks produced from Mix IB display a decrease, and the bricks produced from Mix IC a greater decrease, in apparent specific gravity over bricks produced from the Control.
Decrease of apparent specific gravity is indicative of an increase in the percentage of sealed pores within the brick and, in addition to leading to the reduced water absorption, tends to lower thermal conductivity values.
Table II is similar to Table I, and compares the properties of dry press bricks produced from another control clay-based body, Mix IIA, against those of bricks produced from the clay-based body having 2.5% by weight powdered glass added, Mix IIB, and bricks produced from the clay-based body having 5.0% by weight powdered glass added, Mix IIC.
jl/ -8-~9183 TABLE II
Mix, % by weightIIA (Control)IIB IIC
Buff Fireclay 25 25 25 Red Shale 42 42 42 Calcined Fireclay28 28 28 Grog 5 5 5 Powdered Glass % by Weight Over ~ Above 0.0 2.5 5.0 -Moisture Content as Pressed, % 6.0 6.0 6.0 Forming Pressure, psi 2415 2415 2415 Burning Temperature, F 2090 2090 2090 Modulus of Rupture, psi 1446 1924 2379 Net Area Compressive Strength, psi 7183 10030 13790 Apparent Porosity, % 17.3 14.0 10.4 Water Absorption, % 8.2 6.5 4.8 Bulk Density, pcf143.1 143.0 139.9 Apparent Specific Gravity 2.572.50 2.39 Colour .Standard Standard Slight Darkening Autumn Leaf Autumn of Autumn Leaf Colour Leaf Colour As in the case of Table I, the bricks produced from the powdered glass-containing mixes, Mixes IIB and IIC, display increased compressive strength, decreased water absorption and decreased apparent specific gravity over bricks produced from the Control.
Table III compares the properties of dry press bricks produced from a further clay-based body having gradiated amounts ranging from 0.25% to 1.00% by weight of powdered glass added, Mixes IIIA through IIID, against bricks produced from a control clay-based body, Mix IIIE. Since the powdered glass ~ lt _g_ llZ~83 is most reactive with low refractoriness dry press clay matrices, an impure red burning shale based mix was employed to illustrate the effectiveness of even small amounts of the powdered glass.
TABLE III
Mix, % by weight IIIA IIIB IIIC IIID IIIE
~Control) Red Shale 51 51 51 51 51 Buff Fireclay 8 8 8 8 8 Calcined Fireclay 27 27 27 27 27 Grog (Red) 14 14 14 14 14 Powdered Glass Z by Weight Gver & Above1.000.75 0.50 0.25 0.00 Modulus of Rupture, psi 806 761 686 635 600 Net Area Compressive Strength, psi 3535 3272 2770 2785 2440 Water Absorption, %11.4 11.7 11.6 11.6 12.1 Bulk Density, pcf125.0 124.9 125.3 125.5 125.9 Green-Fired Shrinkage, % 1.85 1.83 1.76 1.72 1.76 Colour Standard Standard Standard Standard Standard Colour Coloor Colour Colour Colour j ],/ ~10 1~29~3 It may be noted from Table III that the bricks produced from Mixes IIIA through IIID all display improvement, albeit modest in the bricks produced from Mix IIID, of all properties re~ative to the bricks produced from the Control.
Table IV compares the properties of dry press bricks produced from another Control clay-based body, Mix IVA, against those of bricks produced from the clay-based body - having gradiated amounts ranging from 5.0% to 15% by weight of powdered glass added, Mixes IVB through IVD. Since the .-powdered glass is least reactive with high refract~riness dry press clay matrices, a high purity buff burning Cone 34 kaolinitic clay was employed to illustrate the effects . of relatively large additions of powdered glass.
TABLE IV
.
Mix, % by weight IVA (Control) IVB IVC IVD
Kaolinitic Clay 100 95 90 85 Powdered Glass % by Weight Over & Above - 5 10 15 Modulus of Rupture, psi 165721602460 1585 Net Area Compressive Strength, psi 6115 9942 15062 6005 Water Absorption, % 6.3 4.5 5.0 8.2 Bulk Derlsity, pcf 140.7 138.0 133.5 124.6 Wet--Fired Shrinkage, % 11.2310.068.63 6.82 Colour Clean Clean Slightly Dark Buff Buff Greying Grey &
Colour Colour of Clean Bloated BufE
Colour
brn:)~
llZ9183 TABLE I
Mix, % by weightIA (Control) IB IC
Buff Fireclay 56 56 56 Fireclay 14 14 14 Calcined Fireclay25 25 25 Grog (Buff) 5 5 5 Powdered Glass % by weight Over ~ Above 0.0 2.5 5 Moisture Content as Pressed, % 6.0 6.0 6.0 Forming Pressure, psi 2415 2415 2415 Burning Temperature, F 2290 2290 2290 Modulus of Rupture, psi 1645 2044 2180 Net Area Compressive Strength, psi 8259 10690 13960 Apparent Porosity, % 20.7 18 12.5 Water Absorption, % 10.0 8.6 6.0 Bulk Dengity, pc~142.7 142.0 130.6 Apparent Specific Gravity 2.62 2.55 2.39 Colour Standard Standard Slight Darkening Golden Golden of Golden Buff Buff BuffColour Colour Colour i1/ -7-~lZ9183 It may be noted from Table I that the bricks produced from Mix IB display a significant increase in compressive strength over bricks produced from the Control, and that the bricks produced from Mix IC display an even more marked increase in compressive strength.
It may further be noted from Table I that the bricks produced from Mix IB display a decrease, and the bricks produced from Mix IC a greater decrease, in water absorption over bricks produced from the Control, indicative of increased resistance to penetration and passage of moisture, liquid and vapour through the bricks.
It may additionally be noted from Table I that the bricks produced from Mix IB display a decrease, and the bricks produced from Mix IC a greater decrease, in apparent specific gravity over bricks produced from the Control.
Decrease of apparent specific gravity is indicative of an increase in the percentage of sealed pores within the brick and, in addition to leading to the reduced water absorption, tends to lower thermal conductivity values.
Table II is similar to Table I, and compares the properties of dry press bricks produced from another control clay-based body, Mix IIA, against those of bricks produced from the clay-based body having 2.5% by weight powdered glass added, Mix IIB, and bricks produced from the clay-based body having 5.0% by weight powdered glass added, Mix IIC.
jl/ -8-~9183 TABLE II
Mix, % by weightIIA (Control)IIB IIC
Buff Fireclay 25 25 25 Red Shale 42 42 42 Calcined Fireclay28 28 28 Grog 5 5 5 Powdered Glass % by Weight Over ~ Above 0.0 2.5 5.0 -Moisture Content as Pressed, % 6.0 6.0 6.0 Forming Pressure, psi 2415 2415 2415 Burning Temperature, F 2090 2090 2090 Modulus of Rupture, psi 1446 1924 2379 Net Area Compressive Strength, psi 7183 10030 13790 Apparent Porosity, % 17.3 14.0 10.4 Water Absorption, % 8.2 6.5 4.8 Bulk Density, pcf143.1 143.0 139.9 Apparent Specific Gravity 2.572.50 2.39 Colour .Standard Standard Slight Darkening Autumn Leaf Autumn of Autumn Leaf Colour Leaf Colour As in the case of Table I, the bricks produced from the powdered glass-containing mixes, Mixes IIB and IIC, display increased compressive strength, decreased water absorption and decreased apparent specific gravity over bricks produced from the Control.
Table III compares the properties of dry press bricks produced from a further clay-based body having gradiated amounts ranging from 0.25% to 1.00% by weight of powdered glass added, Mixes IIIA through IIID, against bricks produced from a control clay-based body, Mix IIIE. Since the powdered glass ~ lt _g_ llZ~83 is most reactive with low refractoriness dry press clay matrices, an impure red burning shale based mix was employed to illustrate the effectiveness of even small amounts of the powdered glass.
TABLE III
Mix, % by weight IIIA IIIB IIIC IIID IIIE
~Control) Red Shale 51 51 51 51 51 Buff Fireclay 8 8 8 8 8 Calcined Fireclay 27 27 27 27 27 Grog (Red) 14 14 14 14 14 Powdered Glass Z by Weight Gver & Above1.000.75 0.50 0.25 0.00 Modulus of Rupture, psi 806 761 686 635 600 Net Area Compressive Strength, psi 3535 3272 2770 2785 2440 Water Absorption, %11.4 11.7 11.6 11.6 12.1 Bulk Density, pcf125.0 124.9 125.3 125.5 125.9 Green-Fired Shrinkage, % 1.85 1.83 1.76 1.72 1.76 Colour Standard Standard Standard Standard Standard Colour Coloor Colour Colour Colour j ],/ ~10 1~29~3 It may be noted from Table III that the bricks produced from Mixes IIIA through IIID all display improvement, albeit modest in the bricks produced from Mix IIID, of all properties re~ative to the bricks produced from the Control.
Table IV compares the properties of dry press bricks produced from another Control clay-based body, Mix IVA, against those of bricks produced from the clay-based body - having gradiated amounts ranging from 5.0% to 15% by weight of powdered glass added, Mixes IVB through IVD. Since the .-powdered glass is least reactive with high refract~riness dry press clay matrices, a high purity buff burning Cone 34 kaolinitic clay was employed to illustrate the effects . of relatively large additions of powdered glass.
TABLE IV
.
Mix, % by weight IVA (Control) IVB IVC IVD
Kaolinitic Clay 100 95 90 85 Powdered Glass % by Weight Over & Above - 5 10 15 Modulus of Rupture, psi 165721602460 1585 Net Area Compressive Strength, psi 6115 9942 15062 6005 Water Absorption, % 6.3 4.5 5.0 8.2 Bulk Derlsity, pcf 140.7 138.0 133.5 124.6 Wet--Fired Shrinkage, % 11.2310.068.63 6.82 Colour Clean Clean Slightly Dark Buff Buff Greying Grey &
Colour Colour of Clean Bloated BufE
Colour
3~
JL/
l~Z9183 The bricks produced from both Mixes IVB and IVC
display significant improvements in properties relative to the bricks produced from the Control, although a slight, but acceptable, greying in tonal colour was evident in the bricks produced from Mix IVC. Interpolation of the results of Table IV suggests a maximum addition of powdered glass of about 12.5% by weight, although as stated earlier the maximum amount is in practice dictated by the extent of colour degradation acceptable, and will vary according to the particular composition of the clay-based body.
Table V compares the significance of grog content to the reactivity of powdered glass in dry press clay-based body mixes. Comparat;ve experiments were conducted to determine whether the powdered glass was preferentially reacting with high grog content clay-based body mixes.
TABLE V
Mix, % by weight Y~ (Control? VB VC (control) VD
Red Shale 51 51 51 51 Buff Fireclay 8 8 44 44 Calcines & Grog41 41 5 5 Pcwdered Glass ~ by Weight Over & Akove 0,0 2 5 o~o ~ ~ 2 5 .. .
~bdulus of Rupture~ psi 600 908 1169 1372 Net Area Compressive Strength, psi 2440 3592 5257 6469 Water Absorption~ % 12.1 11 3 9 7 9 4 Bulk Density, pcf 125 9 126 2 131 3 131 4 Wet-Fired Shrinka~e~ % lt76 2 02 1 96 2 12 Colour Standard Standard Standard Standard Colour Colour ColourColour bm~
~129183 Table V indicates that the addition of the powdered glass leads to property improvement of the bricks regardless of grog content. The grog content does however influence the degree of improvement since high grog content mixes always tend to be more open textured and have lower compressive strength than low grog content mixes, and thus display a ~more pronounced improvement upon addition of the powdered glass.
Table VI compares the properties of bricks, all produced by the stiff mud process, from a Control clay-based body, - Mix VIA, agains~ those of bricks produced from the clay-based body having 2.5% by weight powdered glass added, Mix :~ VIB, and bricks produced from the clay-based body having 5.0% by weight powdered glass added, Mix VIC.
TABLE VI
Mix, % by weightVIA (Control)VIB VIC
Red Shale 51 51 51 Buff Shale 44 44 44 Grog 5 5 5 Powdered GlasR % by Weight Over & Above 0.0 2.5 5.0 ModuluR of Rupture, psi 3197 - 3840 3119 Net Area Compressive Strength, psi12505 20032 15069 Water Absorption, % 4.7 4.4 4.2 Bulk Density, pcf 141.6 140.0 138.6 Wet-Fired Shrinkage, % 8.7 8.8 8.S
Colour Standard Standard Slight Colour ColourDarkening of Standard Colour jl/ -13-~129'183 As in the case of Tables I and II, the bricks produced from the powdered glass-containing mixes, Mixes VIB and VIC, display recogni~able improvements in properties over those of bricks produced from the Control. However, since brick manufacture by the stiff mud process generally produces products of lower porosity and higher compressive streng~h than those manufactured by the dry press process, the degree of improvement is relatively lower.
In summary, the inclusion of powdered glass in an amount in the range of about 0.25 to about 12.5% by weight intimately admixed in the clay-based body from which a kiln burned brick is produced, whether by the dry press process or the stiff mud process, results in a brick of increased compressive strength, decreased water absorption and lower apparent specific gravity, relative to a kiln burned brick lacking powdered glass intimately admixed with the clay-based body from which it is produced.
Of significance, the inexpensively obtained, marked increase in compressive strength in bricks produced by the power press process, while maintaining the prerequisite colour characteristics, permits minimi~ation of elaborate and expensive quality control with assurance that all bricks produced will possess a predictable minimum compressive strength.
Modifications falling within the true broad spirit and scope of the invention will be readily apparent to those skilled in the art.
JL/
l~Z9183 The bricks produced from both Mixes IVB and IVC
display significant improvements in properties relative to the bricks produced from the Control, although a slight, but acceptable, greying in tonal colour was evident in the bricks produced from Mix IVC. Interpolation of the results of Table IV suggests a maximum addition of powdered glass of about 12.5% by weight, although as stated earlier the maximum amount is in practice dictated by the extent of colour degradation acceptable, and will vary according to the particular composition of the clay-based body.
Table V compares the significance of grog content to the reactivity of powdered glass in dry press clay-based body mixes. Comparat;ve experiments were conducted to determine whether the powdered glass was preferentially reacting with high grog content clay-based body mixes.
TABLE V
Mix, % by weight Y~ (Control? VB VC (control) VD
Red Shale 51 51 51 51 Buff Fireclay 8 8 44 44 Calcines & Grog41 41 5 5 Pcwdered Glass ~ by Weight Over & Akove 0,0 2 5 o~o ~ ~ 2 5 .. .
~bdulus of Rupture~ psi 600 908 1169 1372 Net Area Compressive Strength, psi 2440 3592 5257 6469 Water Absorption~ % 12.1 11 3 9 7 9 4 Bulk Density, pcf 125 9 126 2 131 3 131 4 Wet-Fired Shrinka~e~ % lt76 2 02 1 96 2 12 Colour Standard Standard Standard Standard Colour Colour ColourColour bm~
~129183 Table V indicates that the addition of the powdered glass leads to property improvement of the bricks regardless of grog content. The grog content does however influence the degree of improvement since high grog content mixes always tend to be more open textured and have lower compressive strength than low grog content mixes, and thus display a ~more pronounced improvement upon addition of the powdered glass.
Table VI compares the properties of bricks, all produced by the stiff mud process, from a Control clay-based body, - Mix VIA, agains~ those of bricks produced from the clay-based body having 2.5% by weight powdered glass added, Mix :~ VIB, and bricks produced from the clay-based body having 5.0% by weight powdered glass added, Mix VIC.
TABLE VI
Mix, % by weightVIA (Control)VIB VIC
Red Shale 51 51 51 Buff Shale 44 44 44 Grog 5 5 5 Powdered GlasR % by Weight Over & Above 0.0 2.5 5.0 ModuluR of Rupture, psi 3197 - 3840 3119 Net Area Compressive Strength, psi12505 20032 15069 Water Absorption, % 4.7 4.4 4.2 Bulk Density, pcf 141.6 140.0 138.6 Wet-Fired Shrinkage, % 8.7 8.8 8.S
Colour Standard Standard Slight Colour ColourDarkening of Standard Colour jl/ -13-~129'183 As in the case of Tables I and II, the bricks produced from the powdered glass-containing mixes, Mixes VIB and VIC, display recogni~able improvements in properties over those of bricks produced from the Control. However, since brick manufacture by the stiff mud process generally produces products of lower porosity and higher compressive streng~h than those manufactured by the dry press process, the degree of improvement is relatively lower.
In summary, the inclusion of powdered glass in an amount in the range of about 0.25 to about 12.5% by weight intimately admixed in the clay-based body from which a kiln burned brick is produced, whether by the dry press process or the stiff mud process, results in a brick of increased compressive strength, decreased water absorption and lower apparent specific gravity, relative to a kiln burned brick lacking powdered glass intimately admixed with the clay-based body from which it is produced.
Of significance, the inexpensively obtained, marked increase in compressive strength in bricks produced by the power press process, while maintaining the prerequisite colour characteristics, permits minimi~ation of elaborate and expensive quality control with assurance that all bricks produced will possess a predictable minimum compressive strength.
Modifications falling within the true broad spirit and scope of the invention will be readily apparent to those skilled in the art.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a method of making brick wherein a clay-based body is formed to a desired shape and subsequently kiln burned to maturity, the improvement comprising intimately admixing powdered glass in an amount in the range of about 0.25 to about 12.5% by weight with said clay-based body prior to said step of forming.
2. A method according to Claim 1 wherein the powdered glass has a particle size of about -65 mesh or less.
3. A method according to Claim 2, wherein the clay-based body includes a particulate shrinkage control agent in an amount of about 5.0 to about 80.0% by weight to reduce green to fired shrinkage, said agent being comprised of one or more members selected from the group consisting of calcined refractory clay, naturally occurring aggregate or sand, calcined non-refractory clay or shale and grog.
4. A method according to Claim 1, 2 or 3, wherein the powdered glass is of a chemical composition of about 60.0 to 80.0% by weight SiO2, about 0.1 to 5.0% by weight A12O3, about 5.0 to 18.0% by weight Na2O, about 0.0 to 5.0% by weight K2O, about 0.01 to 1.0% by weight Fe2O3 about 0.1 to 5.0% by weight MgO and about 5.0 to 15.0% by weight CaO.
5. A method according the Claim 1, 2 or 3, wherein the powdered glass is of a chemical composition of about 60.0 to 80.0% by weight SiO2, about 0.1 to 5.0% by weight A12O3, about 5.0 to 18.0% by weight Na2O, about 0.0 to 5.0% by weight K2O, about 0.01 to 1.0% by weight Fe2O3 about 0.1 to 5.0% by weight MgO, about 5.0 to 15.0% by weight CaO, and a trace amount of one or more members selected from the group consisting of AS2O3, Cr2O3, B2O3 Co3O4 Sb2O3 and TiO2.
6. A method according to Claim 1, 2 or 3, wherein the brick is formed by the stiff mud process.
7. A method according to Claim 1, 2 or 3, wherein the brick is formed by the stiff mud process, and wherein the clay-based body includes a particulate shrinkage control agent, ground to -4 mesh or finer, in an amount of about 5.0 to about 65.0% by weight to reduce green to fired shrinkage, said agent being comprised of one or more members selected from the group consisting of calcined refractory clay, naturally occurring aggregate or sand, calcined non-refractory clay or shale and grog.
8. A method according to Claim 1, 2 or 3, wherein the brick is formed by the dry press process
9, A method according to Claim 1, 2 or 3, wherein the brick is formed by the dry press process, and wherein the clay-based body additionally includes a particulate shrinkage control agent, ground to -4 mesh or finer, in an amount of about 5.0 to about 80.0% by weight to reduce green to fired shrinkage, said agent being comprised of one or more members selected from the group consisting of calcined refractory clay, naturally occurring aggregate or sand, calcined non-refractory clay or shale and grog.
10. A method according to Claim 1, 2 or 3, wherein the powdered glass is employed in an amount in the range of about 0.5 to about 5.0% by weight,
11. A method according to Claim 1, 2 or 3, wherein said powdered glass is employed in an amount of about 2.5% by weight.
12. A kiln burned brick of increased compressive strength, decreased water absorption and lowered apparent specific gravity, relative to a kiln burned brick lacking powdered glass intimately admixed with the clay-based body from which it is produced, prepared according to the method of Claim 1, 2 or 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA352,213A CA1129183A (en) | 1980-05-20 | 1980-05-20 | Brick making |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA352,213A CA1129183A (en) | 1980-05-20 | 1980-05-20 | Brick making |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129183A true CA1129183A (en) | 1982-08-10 |
Family
ID=4116989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA352,213A Expired CA1129183A (en) | 1980-05-20 | 1980-05-20 | Brick making |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1129183A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2379658A (en) * | 2001-09-15 | 2003-03-19 | Terry Palmer | Ceramic composition with frost resistance |
-
1980
- 1980-05-20 CA CA352,213A patent/CA1129183A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2379658A (en) * | 2001-09-15 | 2003-03-19 | Terry Palmer | Ceramic composition with frost resistance |
| GB2379658B (en) * | 2001-09-15 | 2005-04-13 | Terry Palmer | Frost resistant ceramic |
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