CA2110721A1 - Manufacture of ceramic products - Google Patents
Manufacture of ceramic productsInfo
- Publication number
- CA2110721A1 CA2110721A1 CA002110721A CA2110721A CA2110721A1 CA 2110721 A1 CA2110721 A1 CA 2110721A1 CA 002110721 A CA002110721 A CA 002110721A CA 2110721 A CA2110721 A CA 2110721A CA 2110721 A1 CA2110721 A1 CA 2110721A1
- Authority
- CA
- Canada
- Prior art keywords
- ceramic
- ceramic composition
- approximately
- spent
- weight
- 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.)
- Abandoned
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
- C04B33/18—Compounding ingredients for liquefying the batches
-
- 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
- C04B33/132—Waste materials; Refuse; Residues
- C04B33/1324—Recycled material, e.g. tile dust, stone waste, spent refractory material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Dispersion Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
A ceramic composition including: approximately 80 % to 99.9 % by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approximately 0.1 % to 10 % based on the total weight of the ceramic composition of a spent refractory material.
Description
WO ~2/21~i33 PCI~/AU92/00244 MANUFACTURE OF CERAMI C PRODU~TS
The present invention relates to a ceramic composition including a æpent refractory material, and a process for preparing a ceramic article therefrom.
5Refractory materials are used in numerous enqineering applications, for example as liningæ for heating a~pliances such as kilns, furnaces and the like.
For example aluminium is generally produced by electrolysis of aluminas. A reduction pot is used which is lined on its side and bottom with carbonaceous and luminous ceramic materials. During the life of the pot the lining material iæ gradually destroyed by the intake of bath components and due to chemical reactions taking place inside the liner. Eventually the liners fail and have to be replaced.
The spent potlining contains substantial quantities of water soluble fluorides, particularly NaF. In addition, spent potliner contains water soluble cyanides, generally as NaCN. Disposal of spent potlining has posed a problem because of the leaching of fluorides and cyanides into ground water and resultant pollution thereof. On the other hand, spent potlining is a valuable resource with a high content of chemical and calorific values.
Suggestions have been made in the prior art as to how such valuable resources may be esploited. For example, an article in Light Metals 1989 entitled ~The use of spent potlining as a flux in making steel~ describes the utilization of fluoride values contained in spent potlining as a flu~ in open hearth furnaces. Brazilian Patent No. 850 4924 discloses a method wherein the carbon contained in spent potlining is used as a fuel for the firing of clay bricks.
An article in the Journal of Metal, July 1984, entitled ~Disposal of spent potlining by fluid bed combustion~ describes a process by which the carbon con~ent of spent potlining is burnt off at about 800C.
Cyanides are destroyed. The major disadvantage of this method is the high content of water soluble fluoride in the resulting ash with its attendant pollution difficulties. Suitable additives~ have to be added to the W09~2~633 ~ 7 21 PCT/AU92/~U~
ash in order to immobilize the fluorides and to make the ash environmentally safe for disposal. This post-treatment of the ash cancels, to a large e~tent, the weight reduction achieved in the incineration of spent potlining.
It would be a considerable advance in the art if the sodium and fluoride values contained in spent ceramic materials, such as spent aluminium potlining, could be utilised and still avoid the potential pollution difficulties related thereto.
It is accordi~gly an object of the pre~ent invention to overcome, or at l~ast alleviate, one or mor~
of t~e difficulties related to the prior art.
Accordingly in a first aspect of the pre~ent invention there is provided a ceramic composition including approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approsimately 0.1~ to 10% based on the total weight of the ceramic ~omposition of a spent ref ractory ~aterial.
The ceramic composition according to this aspect of the present invention may be utilised in a process for preparing ceramic articles such as bricks, pipes, tiles and the like.
The ceramic feedstock material may be of any suitable type. The ceramic feedstock material may be a clay-based material. A brick clay may be used. A
bentonite clay, kaolinite, or montmorillonite, or mixtures thereof, may be used. The ceramic feedstock material may be present in any suitable amounts. The ceramic feedstock material is present in amounts of from appro~imately 80%
to 99.9% by weight based on the total weight of the ceramic composition. The ceramic feedstock material is preferably present in amounts of from approsimately 85% to 99.5% by weight.
The spent refractory material may be of any suitable type. The spent refractory material may includè
spent liner from a heatin~ appliance such as a kiln, WO~V21633 PCT/AU9~00 ~
-3- ~11 0721 furnace or the like. The spent refractory material may include carbonaceous residues. The spent refractory material may include sodium and fluoride residues. The spent refractory material may include cyanide, for e~ample sodium cyanide NaCN residues. A spent refractory material from an aluminium reduction pot is preferred.
The spent refractory material is present in amounts of from approsimately 0.1% to 10%, preferably 0.5%
to 5% by weight, based on the total weight of the ceramic composition.
The spent refractory material may be provided in the form of an ash. The spent refractory material may be burnt or incinerated to produce an ash in any suitable manner as discussed below. The æpent refractory ash i8 preferred where health and environmental requlations require material which is chemically less active than the spent refractory material. The burning of the spent refractory material may reduce or eliminate water soluble cyanides such as sodium cyanide. The burninq of the spent refractory material also reduces its weiqht, thereby minimising transport and handling costs.
~The spent refractory material may be provided in a -~crushed form. The spent refractory material may be crushed to a size of less than appro~imately 5 mm, preferably less than approsimately 1 mm.
;~Accordingly, in a further preferred aspect of the present invention there is provided a ceramic composition , including approsimately 80~ to 95.5% by weight based on the -~30~ total weight of the ceramic composition of a brick clay;
approsimately 0.5% to 5% by weight of a crushed spent refractory ash including sodium and fluoride ~ ..
~ residues; and , ~ ~
0 to approsimately 19.5% by weight of ceramic compounding materials.
The ceramic composition according to this aspect of the present inven~ion may further include other standard ceramic compounding materials, for esample , fillers such as siliceous materials, such as sand, - ~ .
WO9~21633 2 1 1 ~ 7 2 1 PCT/AU~0K~4 diatomites, silicates and the like; brick waste, cement and the like, metal osides, metal salts, carbonaceous products and the like, and mi2tures thereof. 8uch ceramic compounding ingredients may comprise from 0 to approsimately 25~ by weiqht, preferably 10% by weight, baæed o~ the total weight of the ceramic composition.
As stated above, the ceramic ~omposition may be utilised in the preparation of ceramic articles.
Accordingly, in a further aspect of the present invention there is provided a process for the preparation of a ceramic article, which process includes providing a ceramic composition including approximately 80% to 99.9~ by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approsimately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material; and water;
contacting the c~ramic composition with water and forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the shaped product at reduced temperature to form a ceramic article.
The ceramic article so formed may be selected from a ceramic brick, tile, pipe or the like.
It will be understood that the spent refractory material functions as a flus in the process for the manufacture of the ceramic article. This flus this reduces the firing temperature required, and thus reduces energy costs of the process.
The firing step may further reduce or eliminate any cyanides present in the spent refractory material.
The firing step may further immobilize any water soluble fluorides present in the ceramic matris formed. This then significantly reduces~ environmental hazards whilst WO~U21633 2 1 1 0 7 2 1 PCT/AU9~00~
permitting the utilisation of the sodium and fluoride values as a flux in the spent refractory material.
As stated above, the ceramic feedstock material is preferably a clay-based material, more preferably a brick 5 clay.
The spent ref ractory material may be provided in a crushed form. Accordingly, in a preferred aspect of the present invention the process may include the preliminary step of crushing the spent refractory material.
As stated above, the spent refractory material may be crushed to a size of less than appro~i~ately 5 mm, preferably less than appro~imatsly 1 mm.
In a further pre~erred aspect, the process may include the preliminary step of ~ubjecting the ~rush~d spent refractory material to a heating step to form a spent refractory a h.
The heating or incineration step may be conducted at a temperature of appro~imately 500C to 1500C, preferably appro~imately 700C to 1200C.
The incineratàon of the 8p8nt refractory material may reduce or eliminate water soluble cyanide residues as discussed above. The incineration o the spent refractory material also reduces the weight of the material, thereby mi~imising transport and handling costs. The incineration step may be carrisd out in any suitable manner and utilising any suitable equipment. For .e~ample, a conv~ntional fluid bed combuster, a toroidal fluid bed fur~ace, a rotary kiln, a m~ltiple hearth furnace, a cyclone furnace or like equipment ~ay be used.
The wetting and shape-forming steps in the process according to this aspect of the present invention may take any suitable form. In one form, water may ba added to the ceramic composition after mising of the components thereof, and the mi~ture allowed to stand for a period sufficient to allow penetration of water into the ceramic romposition. The misture may be allowed to stand for a period of 5 to ~4 hours.
The shape-forming step may take the form of an estrusion or moulding operation. Conventional extrusion WO9~21633 PCT/AU92/00~
~1 10 721 -6-or moulding steps as used in the ceramic arts may be used.
The drying step may be of any suita~le type. The formed material may be air dried, for e~ample in a conventional drying kiln. Air drying may continue for a period of approximately 12 to 48 hours. The duration of the drying ætep may be reduced by increasing the temperature ælightly, e.g. to approsimately 35C to 45C.
The firing step according to the process of the present invention may .be conducted in a conventional firing kiln. A gas kiln may be used. The firing may be undertaken at a reduced temperature of from approsimately 750C to 1200C, preferably appro~imately 900C ~o 1100C.
The firing step may continue for a period sufficient to permit th~ ceramic material to be formed. The~ firing step may continue for approximately 24 to 48 hours.
As stated above, firing may be conducted at reduced temperatures relative to the prior art due to the flu~ing action of the sodium and fluoride residues in the spent rsfractory material, thus reducîng eneryy costs.
Accordingly, in a preferred form, the proc~ss for preparing a ceramic article according to the present invention may include providing appro~ima~ely 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
appro~imately 0.5 to S~ by weight of a crushed spent refractory ash including sodium and fluoride residues; and 0 to approximately 19.5% by weight of ceramic compounding materials; and water;
contacting the ceramic composition with water and permitting the misture to stand for a period sufficient to permit the water to penetrate the ceramic composition;
forming the wetted ceramic composition into a desired shape;
- drying the shaped product; and firing the dried shaped product at a reduced~
WO9~21633 PCT/AU92/00 _7- ~?1t 0 7 temperature to form a ceramic article.
The invention will be more fully described with reference to the following examples. It should be understood, however, that the following description is illustrative only and should not be taken in any way as a restriction on the generality of the invention described above.
Spent potlining containing 27~ C, 18% Na, 15~ F, 24% A12O3 and 12% SiO2 was ground to less than 0.6 mm. The ground potlining was added to standard brick clay at 3~ of the total mis. The materials were then mi2ed dry, water was added, and the misture allowed to stand overnight to allow penetration of the water. The misture was then hand wedged, rolled and cut into bars approximately 5 cm x 3 cm ~ 15 cm~ For comparison sample bars were prepared from said clay without the addition of spent potlining. The samples were air dried for 24 hours and then fired in a gas kiln at temperatures between 950C
and 1050C. Firinq time was 30 h.
To assess the strength of the fired sample bars th~
modulus of rupture ~MOR) was determined by breaking the bars, using a span of 72 mm, in a Shimadzu testing machine.
The water absorption of fired samples was determined by soaking sample bars in cold water for 24 hours, then weighing.
The following results were obtained ..
:
WO9~21633 ~ 2 -8- PCTtAU~/00 % spent Firing temperature ~C) potlining in dry mi~ture _ _ _ _ _ _ 950 l000 1050 .
MOR (mega pascals) 12 15.5 17.4 3 water absorption l0.9 9.2 7.5 ~ fired weight) MOR (mega pascals) 7.5 l0.6 . l0.l 0 water absorption 12.4 ll.5 ll.l (% fired weight) A ~uperior sample brick with higher strength and lower water absorption was obtained at lower firing temperature by adding spent potl;ning to the clay.
~XAMPLE 2 Brick æample bars were prepared and processed as described in Esample 1 with spent potlining containing 66%
C, 17% ~a, 16% F, 23% Al2O3 and S~ SiO2. The modulus of rupture (MOR) and water absorption of fired bars : ~ containing 3% of said spent potlinin~ in the total mis are compared with fired br.ick samples without spent potlining.
WO9~21633 PCT/AU~/00~
9 ~ 7 2 1 % spent Firing temperature (C) potlining in dry mi~ture , 950 1000 105~
MOR (mega pascals) 12.3 15.2 15.6 3 water absorption 9.7 8.3 7.3 (% fired weight) ~OR (mega pascals) 7.5 10.6 10~1 0 water absorption 12.4 11.5 11.1 (% fired weiqht) .
As in Esample 1, a superior ~ample bric~ was obtained at lower firin~ temperature by adding spent potlining to the clay misture.
~XAMP~E 3 Spent potlining was calcined in a muffle furnace at 800~C for 4 hrs. The ash containing less than 2~ C, 20%
~a, 16% F, 35% A12O3 and 14% SiO2 was ground to less than 0.6 mm. A clay mi~ture containing 3% of said spent potliner ash was prepared and pro~essed as described in Esample 1.
Fîred sample bars were assessed for stren~th and water absorption as described in E~ample 1. The following results were obtained.
The present invention relates to a ceramic composition including a æpent refractory material, and a process for preparing a ceramic article therefrom.
5Refractory materials are used in numerous enqineering applications, for example as liningæ for heating a~pliances such as kilns, furnaces and the like.
For example aluminium is generally produced by electrolysis of aluminas. A reduction pot is used which is lined on its side and bottom with carbonaceous and luminous ceramic materials. During the life of the pot the lining material iæ gradually destroyed by the intake of bath components and due to chemical reactions taking place inside the liner. Eventually the liners fail and have to be replaced.
The spent potlining contains substantial quantities of water soluble fluorides, particularly NaF. In addition, spent potliner contains water soluble cyanides, generally as NaCN. Disposal of spent potlining has posed a problem because of the leaching of fluorides and cyanides into ground water and resultant pollution thereof. On the other hand, spent potlining is a valuable resource with a high content of chemical and calorific values.
Suggestions have been made in the prior art as to how such valuable resources may be esploited. For example, an article in Light Metals 1989 entitled ~The use of spent potlining as a flux in making steel~ describes the utilization of fluoride values contained in spent potlining as a flu~ in open hearth furnaces. Brazilian Patent No. 850 4924 discloses a method wherein the carbon contained in spent potlining is used as a fuel for the firing of clay bricks.
An article in the Journal of Metal, July 1984, entitled ~Disposal of spent potlining by fluid bed combustion~ describes a process by which the carbon con~ent of spent potlining is burnt off at about 800C.
Cyanides are destroyed. The major disadvantage of this method is the high content of water soluble fluoride in the resulting ash with its attendant pollution difficulties. Suitable additives~ have to be added to the W09~2~633 ~ 7 21 PCT/AU92/~U~
ash in order to immobilize the fluorides and to make the ash environmentally safe for disposal. This post-treatment of the ash cancels, to a large e~tent, the weight reduction achieved in the incineration of spent potlining.
It would be a considerable advance in the art if the sodium and fluoride values contained in spent ceramic materials, such as spent aluminium potlining, could be utilised and still avoid the potential pollution difficulties related thereto.
It is accordi~gly an object of the pre~ent invention to overcome, or at l~ast alleviate, one or mor~
of t~e difficulties related to the prior art.
Accordingly in a first aspect of the pre~ent invention there is provided a ceramic composition including approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approsimately 0.1~ to 10% based on the total weight of the ceramic ~omposition of a spent ref ractory ~aterial.
The ceramic composition according to this aspect of the present invention may be utilised in a process for preparing ceramic articles such as bricks, pipes, tiles and the like.
The ceramic feedstock material may be of any suitable type. The ceramic feedstock material may be a clay-based material. A brick clay may be used. A
bentonite clay, kaolinite, or montmorillonite, or mixtures thereof, may be used. The ceramic feedstock material may be present in any suitable amounts. The ceramic feedstock material is present in amounts of from appro~imately 80%
to 99.9% by weight based on the total weight of the ceramic composition. The ceramic feedstock material is preferably present in amounts of from approsimately 85% to 99.5% by weight.
The spent refractory material may be of any suitable type. The spent refractory material may includè
spent liner from a heatin~ appliance such as a kiln, WO~V21633 PCT/AU9~00 ~
-3- ~11 0721 furnace or the like. The spent refractory material may include carbonaceous residues. The spent refractory material may include sodium and fluoride residues. The spent refractory material may include cyanide, for e~ample sodium cyanide NaCN residues. A spent refractory material from an aluminium reduction pot is preferred.
The spent refractory material is present in amounts of from approsimately 0.1% to 10%, preferably 0.5%
to 5% by weight, based on the total weight of the ceramic composition.
The spent refractory material may be provided in the form of an ash. The spent refractory material may be burnt or incinerated to produce an ash in any suitable manner as discussed below. The æpent refractory ash i8 preferred where health and environmental requlations require material which is chemically less active than the spent refractory material. The burning of the spent refractory material may reduce or eliminate water soluble cyanides such as sodium cyanide. The burninq of the spent refractory material also reduces its weiqht, thereby minimising transport and handling costs.
~The spent refractory material may be provided in a -~crushed form. The spent refractory material may be crushed to a size of less than appro~imately 5 mm, preferably less than approsimately 1 mm.
;~Accordingly, in a further preferred aspect of the present invention there is provided a ceramic composition , including approsimately 80~ to 95.5% by weight based on the -~30~ total weight of the ceramic composition of a brick clay;
approsimately 0.5% to 5% by weight of a crushed spent refractory ash including sodium and fluoride ~ ..
~ residues; and , ~ ~
0 to approsimately 19.5% by weight of ceramic compounding materials.
The ceramic composition according to this aspect of the present inven~ion may further include other standard ceramic compounding materials, for esample , fillers such as siliceous materials, such as sand, - ~ .
WO9~21633 2 1 1 ~ 7 2 1 PCT/AU~0K~4 diatomites, silicates and the like; brick waste, cement and the like, metal osides, metal salts, carbonaceous products and the like, and mi2tures thereof. 8uch ceramic compounding ingredients may comprise from 0 to approsimately 25~ by weiqht, preferably 10% by weight, baæed o~ the total weight of the ceramic composition.
As stated above, the ceramic ~omposition may be utilised in the preparation of ceramic articles.
Accordingly, in a further aspect of the present invention there is provided a process for the preparation of a ceramic article, which process includes providing a ceramic composition including approximately 80% to 99.9~ by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approsimately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material; and water;
contacting the c~ramic composition with water and forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the shaped product at reduced temperature to form a ceramic article.
The ceramic article so formed may be selected from a ceramic brick, tile, pipe or the like.
It will be understood that the spent refractory material functions as a flus in the process for the manufacture of the ceramic article. This flus this reduces the firing temperature required, and thus reduces energy costs of the process.
The firing step may further reduce or eliminate any cyanides present in the spent refractory material.
The firing step may further immobilize any water soluble fluorides present in the ceramic matris formed. This then significantly reduces~ environmental hazards whilst WO~U21633 2 1 1 0 7 2 1 PCT/AU9~00~
permitting the utilisation of the sodium and fluoride values as a flux in the spent refractory material.
As stated above, the ceramic feedstock material is preferably a clay-based material, more preferably a brick 5 clay.
The spent ref ractory material may be provided in a crushed form. Accordingly, in a preferred aspect of the present invention the process may include the preliminary step of crushing the spent refractory material.
As stated above, the spent refractory material may be crushed to a size of less than appro~i~ately 5 mm, preferably less than appro~imatsly 1 mm.
In a further pre~erred aspect, the process may include the preliminary step of ~ubjecting the ~rush~d spent refractory material to a heating step to form a spent refractory a h.
The heating or incineration step may be conducted at a temperature of appro~imately 500C to 1500C, preferably appro~imately 700C to 1200C.
The incineratàon of the 8p8nt refractory material may reduce or eliminate water soluble cyanide residues as discussed above. The incineration o the spent refractory material also reduces the weight of the material, thereby mi~imising transport and handling costs. The incineration step may be carrisd out in any suitable manner and utilising any suitable equipment. For .e~ample, a conv~ntional fluid bed combuster, a toroidal fluid bed fur~ace, a rotary kiln, a m~ltiple hearth furnace, a cyclone furnace or like equipment ~ay be used.
The wetting and shape-forming steps in the process according to this aspect of the present invention may take any suitable form. In one form, water may ba added to the ceramic composition after mising of the components thereof, and the mi~ture allowed to stand for a period sufficient to allow penetration of water into the ceramic romposition. The misture may be allowed to stand for a period of 5 to ~4 hours.
The shape-forming step may take the form of an estrusion or moulding operation. Conventional extrusion WO9~21633 PCT/AU92/00~
~1 10 721 -6-or moulding steps as used in the ceramic arts may be used.
The drying step may be of any suita~le type. The formed material may be air dried, for e~ample in a conventional drying kiln. Air drying may continue for a period of approximately 12 to 48 hours. The duration of the drying ætep may be reduced by increasing the temperature ælightly, e.g. to approsimately 35C to 45C.
The firing step according to the process of the present invention may .be conducted in a conventional firing kiln. A gas kiln may be used. The firing may be undertaken at a reduced temperature of from approsimately 750C to 1200C, preferably appro~imately 900C ~o 1100C.
The firing step may continue for a period sufficient to permit th~ ceramic material to be formed. The~ firing step may continue for approximately 24 to 48 hours.
As stated above, firing may be conducted at reduced temperatures relative to the prior art due to the flu~ing action of the sodium and fluoride residues in the spent rsfractory material, thus reducîng eneryy costs.
Accordingly, in a preferred form, the proc~ss for preparing a ceramic article according to the present invention may include providing appro~ima~ely 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
appro~imately 0.5 to S~ by weight of a crushed spent refractory ash including sodium and fluoride residues; and 0 to approximately 19.5% by weight of ceramic compounding materials; and water;
contacting the ceramic composition with water and permitting the misture to stand for a period sufficient to permit the water to penetrate the ceramic composition;
forming the wetted ceramic composition into a desired shape;
- drying the shaped product; and firing the dried shaped product at a reduced~
WO9~21633 PCT/AU92/00 _7- ~?1t 0 7 temperature to form a ceramic article.
The invention will be more fully described with reference to the following examples. It should be understood, however, that the following description is illustrative only and should not be taken in any way as a restriction on the generality of the invention described above.
Spent potlining containing 27~ C, 18% Na, 15~ F, 24% A12O3 and 12% SiO2 was ground to less than 0.6 mm. The ground potlining was added to standard brick clay at 3~ of the total mis. The materials were then mi2ed dry, water was added, and the misture allowed to stand overnight to allow penetration of the water. The misture was then hand wedged, rolled and cut into bars approximately 5 cm x 3 cm ~ 15 cm~ For comparison sample bars were prepared from said clay without the addition of spent potlining. The samples were air dried for 24 hours and then fired in a gas kiln at temperatures between 950C
and 1050C. Firinq time was 30 h.
To assess the strength of the fired sample bars th~
modulus of rupture ~MOR) was determined by breaking the bars, using a span of 72 mm, in a Shimadzu testing machine.
The water absorption of fired samples was determined by soaking sample bars in cold water for 24 hours, then weighing.
The following results were obtained ..
:
WO9~21633 ~ 2 -8- PCTtAU~/00 % spent Firing temperature ~C) potlining in dry mi~ture _ _ _ _ _ _ 950 l000 1050 .
MOR (mega pascals) 12 15.5 17.4 3 water absorption l0.9 9.2 7.5 ~ fired weight) MOR (mega pascals) 7.5 l0.6 . l0.l 0 water absorption 12.4 ll.5 ll.l (% fired weight) A ~uperior sample brick with higher strength and lower water absorption was obtained at lower firing temperature by adding spent potl;ning to the clay.
~XAMPLE 2 Brick æample bars were prepared and processed as described in Esample 1 with spent potlining containing 66%
C, 17% ~a, 16% F, 23% Al2O3 and S~ SiO2. The modulus of rupture (MOR) and water absorption of fired bars : ~ containing 3% of said spent potlinin~ in the total mis are compared with fired br.ick samples without spent potlining.
WO9~21633 PCT/AU~/00~
9 ~ 7 2 1 % spent Firing temperature (C) potlining in dry mi~ture , 950 1000 105~
MOR (mega pascals) 12.3 15.2 15.6 3 water absorption 9.7 8.3 7.3 (% fired weight) ~OR (mega pascals) 7.5 10.6 10~1 0 water absorption 12.4 11.5 11.1 (% fired weiqht) .
As in Esample 1, a superior ~ample bric~ was obtained at lower firin~ temperature by adding spent potlining to the clay misture.
~XAMP~E 3 Spent potlining was calcined in a muffle furnace at 800~C for 4 hrs. The ash containing less than 2~ C, 20%
~a, 16% F, 35% A12O3 and 14% SiO2 was ground to less than 0.6 mm. A clay mi~ture containing 3% of said spent potliner ash was prepared and pro~essed as described in Esample 1.
Fîred sample bars were assessed for stren~th and water absorption as described in E~ample 1. The following results were obtained.
2 1 1 0 7 ~ 1 PCT/~U92/00~44 .
% spent pot-Firing temperature (C~ liner ash in dry mixture _ MOR (mega pascals) 14.8 18.8 18.9 3 water absorption 10.0 7.5 5.6 (% fired weight) MOR (mega pascals) 7.5 10.6- 10.1 0 water absorption 12.4 11.5 11.1 (% fired weight) As in ~amples 1 and 2 a superior sample brick was obtained at lower fi~ing temperature by the addition of spent potliner aæh.
Water soluble fluoride in spent potlining, spent potliner ash snd fired bricks containing spent potlining or spent potliner ash was determined by treating 1 g of finely ground sample material in 250 mls distilled water at 80C for 30 minutes. After filtering off the residue, was determined in the resulting liguor by ion selective electrode. The following results were obtained.
% wat~r soluble F
of total F
35 Spent potlining 48 Spent potliner ash 36 Fired brick with 3% spent potlining 3 Fired brick with 5% pot~iner ash 3 :
WO ~U21633 ~1 t n 7 21 High immobilization of water soluble F contained in spent potlining and ~pent potliner 2sh was achieved on firing of the clay bricks.
EXAMP~E 5 Cyanide was determined in spent potlining and a fired brick containing 6% spent potlining. The following results were obtained.
Cyanide in spent potlininq (ppm) : 1000 Cyanide in fired brick with 6~
spent potlininy ~ppm~ : <0.~4 Cyanide containea in SP~ was virtually destroyed on firing of the clay brick.
Finally, it is to be understood that various other modifications and/or alterations may be made without departing from the spirit -of the present invention as outlined herein.
% spent pot-Firing temperature (C~ liner ash in dry mixture _ MOR (mega pascals) 14.8 18.8 18.9 3 water absorption 10.0 7.5 5.6 (% fired weight) MOR (mega pascals) 7.5 10.6- 10.1 0 water absorption 12.4 11.5 11.1 (% fired weight) As in ~amples 1 and 2 a superior sample brick was obtained at lower fi~ing temperature by the addition of spent potliner aæh.
Water soluble fluoride in spent potlining, spent potliner ash snd fired bricks containing spent potlining or spent potliner ash was determined by treating 1 g of finely ground sample material in 250 mls distilled water at 80C for 30 minutes. After filtering off the residue, was determined in the resulting liguor by ion selective electrode. The following results were obtained.
% wat~r soluble F
of total F
35 Spent potlining 48 Spent potliner ash 36 Fired brick with 3% spent potlining 3 Fired brick with 5% pot~iner ash 3 :
WO ~U21633 ~1 t n 7 21 High immobilization of water soluble F contained in spent potlining and ~pent potliner 2sh was achieved on firing of the clay bricks.
EXAMP~E 5 Cyanide was determined in spent potlining and a fired brick containing 6% spent potlining. The following results were obtained.
Cyanide in spent potlininq (ppm) : 1000 Cyanide in fired brick with 6~
spent potlininy ~ppm~ : <0.~4 Cyanide containea in SP~ was virtually destroyed on firing of the clay brick.
Finally, it is to be understood that various other modifications and/or alterations may be made without departing from the spirit -of the present invention as outlined herein.
Claims (14)
1. A ceramic composition including:
approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approximately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material.
approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material; and approximately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material.
2. A ceramic composition according to claim 1, wherein the ceramic feedstock material is a clay-based material selected from bentonite clay, kaolinite, montmorillonite, or mixtures thereof.
3. A ceramic composition according to claim 2, wherein the spent refractory material is in the form of an ash.
4. A ceramic composition according to claim 3, wherein the spent refractory material is crushed to a size of less than approximately 5 mm.
5. A ceramic composition including:
approximately 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
approximately 0.5 to 5% by weight of a crushed spent refractory ash including sodium and fluoride residues; and 0 to approximately 19.5% by weight of ceramic compounding materials.
approximately 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
approximately 0.5 to 5% by weight of a crushed spent refractory ash including sodium and fluoride residues; and 0 to approximately 19.5% by weight of ceramic compounding materials.
6. A ceramic composition according to claim 5 wherein the ceramic compounding materials are selected from fillers, brick waste, cement, metal oxides, metal salts, carbonaceous products and mixtures thereof.
7. A process for the preparation of a ceramic article, which process includes:
providing a ceramic composition including approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material;
and approximately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material; and water;
contacting the ceramic composition with water and forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the shaped product at reduced temperature to form a ceramic article.
providing a ceramic composition including approximately 80% to 99.9% by weight based on the total weight of the ceramic composition of a ceramic feedstock material;
and approximately 0.1% to 10% based on the total weight of the ceramic composition of a spent refractory material; and water;
contacting the ceramic composition with water and forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the shaped product at reduced temperature to form a ceramic article.
8. A process according to claim 7, wherein the shaped product is fired at a temperature of from approximately 750°C to 1200°C and continues for approximately 24 to 48 hours.
9. A process according to claim 7 further including the preliminary step of crushing the spent refractory material to a size of less than approximately 5 mm.
10. A process according to claim 9 further including the preliminary step of subjecting the crushed spent refractory material to a heating step at a temperature of approximately 500°C to 1500°C to form a spent refractory ash.
11. A process of preparing a ceramic article including providing a ceramic composition including:
approximately 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
approximately 0.5 to 5% by weight of a crushed spent refractory ash including sodium and fluoride residues;
0 to approximately 19.5% by weight of ceramic compounding materials; and water;
contacting the ceramic composition with water and permitting the mixture to stand for a period sufficient to permit the water to penetrate the ceramic composition;
forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the dried shaped product at a reduced temperature to form a ceramic article.
approximately 80 to 95.5% by weight based on the total weight of the ceramic composition of a brick clay;
approximately 0.5 to 5% by weight of a crushed spent refractory ash including sodium and fluoride residues;
0 to approximately 19.5% by weight of ceramic compounding materials; and water;
contacting the ceramic composition with water and permitting the mixture to stand for a period sufficient to permit the water to penetrate the ceramic composition;
forming the wetted ceramic composition into a desired shape;
drying the shaped product; and firing the dried shaped product at a reduced temperature to form a ceramic article.
12. A ceramic article whenever prepared according to the process of claim 7.
13. A ceramic article according to claim 12 selected from ceramic bricks, tiles and pipes.
14. A process according to claim 7 substantially hereinbefore described with reference to any one of the Examples.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPK6479 | 1991-06-05 | ||
| AUPK647991 | 1991-06-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2110721A1 true CA2110721A1 (en) | 1992-12-10 |
Family
ID=3775446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002110721A Abandoned CA2110721A1 (en) | 1991-06-05 | 1992-05-29 | Manufacture of ceramic products |
Country Status (3)
| Country | Link |
|---|---|
| BR (1) | BR9206090A (en) |
| CA (1) | CA2110721A1 (en) |
| WO (1) | WO1992021633A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ302929B6 (en) * | 2007-01-05 | 2012-01-18 | Palla@Karel | Use of grinding swarfs of conglomerated stone production as an ingredient of clay raw material for brickware, earthenware and similar ceramic products |
| RU2508269C2 (en) * | 2012-01-11 | 2014-02-27 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный аэрокосмический университет имени академика С.П. Королева (национальный исследовательский университет)" (СГАУ) | Ceramic composition for making light brick |
| CN102617167B (en) * | 2012-03-31 | 2013-06-26 | 北京五一环保科技股份有限公司 | Regeneration refractory castable taking used unshaped refractories as main materials |
| RU2502700C1 (en) * | 2012-09-03 | 2013-12-27 | Юлия Алексеевна Щепочкина | Raw material mixture for tile production |
| RU2552246C1 (en) * | 2014-04-08 | 2015-06-10 | Юлия Алексеевна Щепочкина | Ceramic paste for manufacture of facade tiles |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4735784A (en) * | 1986-07-11 | 1988-04-05 | Morrison-Knudsen Company, Inc. | Method of treating fluoride contaminated wastes |
| IT1213929B (en) * | 1987-11-05 | 1990-01-05 | Maurizio Tassara | METHOD OF RECLAMATION OF TOXIC AND HARMFUL INDUSTRIAL WASTE THROUGH GLAZING IN CERAMIC PRODUCTS |
| AU7539491A (en) * | 1990-04-24 | 1991-11-07 | Alcan Australia Limited | Process for treating spent potliner material from an aluminium smelter process and products therefrom |
-
1992
- 1992-05-29 CA CA002110721A patent/CA2110721A1/en not_active Abandoned
- 1992-05-29 BR BR9206090A patent/BR9206090A/en not_active Application Discontinuation
- 1992-05-29 WO PCT/AU1992/000244 patent/WO1992021633A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992021633A1 (en) | 1992-12-10 |
| BR9206090A (en) | 1994-08-02 |
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