CA1241350A - Light ceramic materials for building purposes and methods for their production - Google Patents
Light ceramic materials for building purposes and methods for their productionInfo
- Publication number
- CA1241350A CA1241350A CA000477488A CA477488A CA1241350A CA 1241350 A CA1241350 A CA 1241350A CA 000477488 A CA000477488 A CA 000477488A CA 477488 A CA477488 A CA 477488A CA 1241350 A CA1241350 A CA 1241350A
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- Prior art keywords
- weight
- clay
- parts
- process according
- temperature
- 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
- 238000000034 method Methods 0.000 title claims abstract description 18
- 229910010293 ceramic material Inorganic materials 0.000 title claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 title description 4
- 239000004927 clay Substances 0.000 claims abstract description 34
- 239000004566 building material Substances 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910001868 water Inorganic materials 0.000 claims abstract description 12
- 238000001035 drying Methods 0.000 claims abstract description 11
- 239000006260 foam Substances 0.000 claims abstract description 9
- 238000000465 moulding Methods 0.000 claims abstract description 9
- 238000010304 firing Methods 0.000 claims abstract description 5
- 238000005187 foaming Methods 0.000 claims abstract description 5
- 239000011810 insulating material Substances 0.000 claims abstract description 5
- 239000004094 surface-active agent Substances 0.000 claims abstract description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052572 stoneware Inorganic materials 0.000 claims description 6
- 239000011449 brick Substances 0.000 claims description 5
- 239000004568 cement Substances 0.000 claims description 5
- 239000005995 Aluminium silicate Substances 0.000 claims description 4
- 235000012211 aluminium silicate Nutrition 0.000 claims description 4
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims description 4
- 229910021532 Calcite Inorganic materials 0.000 claims description 3
- 239000006004 Quartz sand Substances 0.000 claims description 3
- 239000000440 bentonite Substances 0.000 claims description 3
- 229910000278 bentonite Inorganic materials 0.000 claims description 3
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 3
- 239000011230 binding agent Substances 0.000 claims description 3
- 239000003245 coal Substances 0.000 claims description 3
- 239000010459 dolomite Substances 0.000 claims description 3
- 229910000514 dolomite Inorganic materials 0.000 claims description 3
- 239000010433 feldspar Substances 0.000 claims description 3
- 230000009974 thixotropic effect Effects 0.000 claims description 3
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 claims description 2
- 229910052901 montmorillonite Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 description 13
- 239000008187 granular material Substances 0.000 description 6
- 239000000725 suspension Substances 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000007792 addition Methods 0.000 description 4
- 239000007767 bonding agent Substances 0.000 description 3
- 239000004567 concrete Substances 0.000 description 3
- 238000012216 screening Methods 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- -1 montmorlllonite Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 235000019830 sodium polyphosphate Nutrition 0.000 description 2
- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical compound [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- 229920006329 Styropor Polymers 0.000 description 1
- 241000030538 Thecla Species 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 244000309464 bull Species 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 235000012255 calcium oxide Nutrition 0.000 description 1
- 229940087373 calcium oxide Drugs 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 235000011007 phosphoric acid Nutrition 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229960001866 silicon dioxide Drugs 0.000 description 1
- XJKVPKYVPCWHFO-UHFFFAOYSA-N silicon;hydrate Chemical compound O.[Si] XJKVPKYVPCWHFO-UHFFFAOYSA-N 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Abstract
ABSTRACT
The invention provides a process for producing a lightweight ceramic material for use in building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace building materials and/or refractory building materials, having a bulk density of 300 to 700 g/liter, which comprises forming a starting mixture containing 45 to 80 parts by weight of clay, 0 to 50 parts by weight of an aggregate, 15 to 30 parts by weight of water, 0,01 to 0,03 parts by weight of a deflocculant and 0,001 to 0,01 parts by weight of a surfactant; foaming the starting mixture at a pressure of 1 to 10 bar by compressed air at a temperature between ambient temperature and 95°C to form a foam; molding and drying the foam to give a dried clay blank;
and firing the dried clay blank at a product temperature between 600 and 1400°C.
The invention provides a process for producing a lightweight ceramic material for use in building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace building materials and/or refractory building materials, having a bulk density of 300 to 700 g/liter, which comprises forming a starting mixture containing 45 to 80 parts by weight of clay, 0 to 50 parts by weight of an aggregate, 15 to 30 parts by weight of water, 0,01 to 0,03 parts by weight of a deflocculant and 0,001 to 0,01 parts by weight of a surfactant; foaming the starting mixture at a pressure of 1 to 10 bar by compressed air at a temperature between ambient temperature and 95°C to form a foam; molding and drying the foam to give a dried clay blank;
and firing the dried clay blank at a product temperature between 600 and 1400°C.
Description
l3~
The invention relates to a light ceramic material usable, for example, for building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace buildiny materials and/or refactory building materials and to a method for producing the said material.
Light structural materials, based upon lime and cement, are already known as so-called "porous concrete or "foam concreten. To this end, mixtures of calcium-oxide, silicon-dioxide and water, with the addition of foaming agents, or in the oamed condition, are hardened in an autoclave.
Although existing porous light structural materials, as known, for example, from European Patent 0 007 585, have satisfactory strength and other properties important for building purposes, they may be too costly to produce for many applications.
It is the purpose of the invention to provide a new light ceramic material which can be used as a light-weight aggregate and also for producing moulded objects, such as bricks, for heat and/or sound-insulating purposes in particular, and also for refractory building purposes, in the form of light compression-proof mouldings, made from simple initial substances, by an economical method.
According to the invention, is provl~ed a process for producing a lightweight ceramic material for use in building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace building materials and/or refractory building materials, having a bull density of 300 to 700 g/liter, which comprises forming a starting mixture containing 45 to 80 parts by weight of clay, 0 to 50 parts by weight of an aggregate, 15 to 30 parts by weight of water, 0 9 01 to 0,03 parts by weight of a deflocculant and 0,001 to 0,01 parts by weight of a surfactant; foaming the starting mixture at a pressure of 1 to 10 bar by compressed air at a temperature between ambient temperature and 95C to form a foam; molding and drying the foam to give a dried clay blank; and firing the dried clay blank at a product temperature between 600 and 1400C.
In this connection it is particularly desirable to use, as aggregate, calcite, quartz sand, dolomite, feldspar, chamotte, sawdust and coal.
If, for production reasons, a product is required with particularly high green strength, as may be the case with products larger than bricks, a hydraulic binder, such as cement, may be added. One special advantage of the method according to the invention is that the clay used may be simple brick-clay, but Westerwalder stoneware clay, fine stoneware clay, kaolin, montmorlllonite, bentonite or marl may also be used.
It is of special interest, from an economical point of view, that, according to the invention, any mouldings that are unsatisfactory after drying or, where granules are used, any fine granular material separated by screening, can be returned, without further treatment, directly to the initial mixture, since they have merely been dried, not fired, and are therefore still fully reactive.
The method according to the invention usually proceeds in such a manner that the cla~v is stirred up with water and the deflocculating agent to form a thixotrophic suspension containing little moisture. To produce a foam-suspension from the clay suspension, surfactant is added and foaming is carried out in a dispersing unit with the addition of compressed air.
.5~
It is possible to make use of conventional dispersing units, as sold by Messrs. Hansa-Mixer, Bremen, under the trade mark ~ansa-~ixer~ which add specific amounts of compressed air under pressure (1 to 10 bars). The dispersing unit has an additional precision-metering pump by means of which fluid may be added before and, if necessary, during the foaming operation. During the execution of the method according to the invention, it is desirable to use a suhstance opposing the action of the deflocculating agent, a deflocculant-counteracting agent, for example dilute hydrochloric acid, this makes it possible to produce highly viscous, thixotropic, inherently stable foam-suspensions.
The inherently stable, thixotropic foam-suspension is then dried, the water-vapour emerglng readily through the pores because of the high porosity of the material. In this connection it is particularly beneficlal if the mixture of initial materials contains a relatively small amount of water.
The dried material is usually obtained in lengths of about 1 cm.
in diameter, the drying times being not more than 5 minutes at temperatures of 200C This dried material is crushed into granules prior to firing.
Due to the porosity of the material, and above all in the case of objects of small dimensions, very favourable processing is possible, such as drying. With a furnace-temperature of between 1000C and 1400C, corresponding to amaterial-temperature of between 800 and 1000C, it is possible to produce light ceramic materials for building purposes with a firing time of less than 5 minutes, including heating-up and cooling-down times. Treatment at an elevated temperature is particularly desirable if the product is to be used for building purposes, since this mazes it possible to obtain particularly satisfactory strength propertles.
The invention also relates to the use of the light ceramic material in the form of a solid and/or granules as a heat and/or sound-insulating material for building purposes, also as an aggregate for high-temperature building materials such as structural materials for furnaces, refractory building materials, and the like.
The aggregates normally used for refractory building materials for example are, of course, also used accordingly, i.e. additions of clay, maynesite, quartz and the like, as required by the particular application.
The light ceramic material may be characterized in that the mixture preferably contains between 60 and 75 parts by weight of clay, 15 to 20 parts by weight of water, 10 to 20 parts by weight of aggregate; 0.001 to 0.01 parts by weight of surfactant, and 0.01 to 0.03 parts by weight of deflocculating agent.
The invention may be further characterized in that the clay blank is dried at a temperature between ambient temperature and 200C.
Further characteristics and advantages of the `nvention may be gathered from the following description, in which examples embodying the invention are explained in detail in conjunction with the diagrammatical drawing attached hereto, which shows a flow-chart of a method according to the invention.
Thus, 45 to 80 parts by weight of clay, 15 to 30 parts by weight of water, if necessary 0 to 50 parts by weight of an aggregate, and 0.01 to 0.03 parts by weight of a deflocculating agent, possibly with an appropriate amount of a hydraulic bonding agent, are mixed together in a conventional mixer. The following may be used as clay, for example: brick clay, Westerwalder stoneware clay, fine stoneware clay, kaolin, montmorillonite, bentonite or marl. Calcite, quartz sand, dolomite, feldspar, chamotte and/or organic materials such as sawdust or coal may be used as the aggregate. Examples of deflocculating agents are: water-glass, ca:Lcium polyphosphate, sodium polyphosphate, phosphoric acid, chlorides or sulphates, Preferably cement may be added as the hydraulic bonding agent in order to achieve higher green strength The mixture made out of the foregoing constituents, and containing little water, is foamed so as to have a litre-weight of between 30 and 80 g/l, and is dried in moulds or by means of a moulding device. Drying may, if necessaryJ be accelerated by establishing a vacuum or by the use of a drying oven. Drying is extremely simple and rapid because of the high porosity of the material to be dried. The dried products are then placed in a furnace having a temperature of between 1000 and 1400C, corresponding to a product temperature of between about ~00 and 1000C, and are fired. In producing light additives, as used in building concrete and the like, it is desirable to use granular material; this may be obtained by passing the dried products through a crusher and a screening unit which retains the preferred grain-size range and discards the fines; the latter may then be returned to the mixer, as shown in the drawing.
500 kg of marl, 400 kg of crushed, dried foamed clay (produced by crushing rejected, dried and not yet flred foamed clay mouldings), 200 litres of water, 120 g of sodium polyphosphate (deflocculating agent), and 100 g of sodium dodecyl-sulphonate (dispersing agent), were foamed in a dispersing unit made by Messrs. Hansa-Mixer, of Bremen, at a pressure of 3 bars, with compressed air. The foamed product was cast in moulds, passed to a drying oven, and dried at 200C for 10 minutes. The dried, foamed-clay mouldings were removed from the moulds, and were fired for 7 minutes in a corlventional furnace and in the usual way, at a furnace-temperature ox about 1400C corresponding to a product temperature of about 1000C.
This produced yellowish-brown light ceramic panels having the following characteristics:
pH value: 7 - 8 pore diameter: 1 mm.
bulk-density: about 0.6 g/cm3 Products made in this way have good heat- and sound-insulating properties and low hygroscopicity. Panels or bricks made in this way may replace glass-fibre wool, asbestos-fibre, rock-wool or styropor for thermal insulation; they may also be used for facing panels or for light partitions, if low weight per unit of volume is necessary, because the sub-soil has insufficient load-carrying capacity.
Example II
800 kg of kaolin, 200 kg of pumice-stone crushed to a grain-size of between l and 2.5 mm, 200 litres of water and 100 g of 5% phosphoric acid were mixed and added to 300 g of sodium-lauryl-sulphonate foam (lltre-weight 70 g/l). This was followed by forming into lengths in a forming unit, then by crushing, in a conventional roller-crusher, to a grain size of between and 5 mm diameter, followed by screening. The fines were separated, all material below the said grain-size being discarded. The crushed product was passed to a furnace having a furnace temperature OL 1000C, was fired for 5 minutes, and the resulting granular material was cooled and packaged. The resulting material is particularly suitable for light additives, for example for light concrete, gypsum-panels, and the like, and possessed compressive strength, bulk-density, and heat-conductivity coefficients which made it appear particularly suitable for these applications. The pH value was between 7 and 8 and the bulk-density was in the vicinity ox 0.6 ~/cm3.
The addition ox hydraulic bonding agents, such as cement, increased the strength values without impairing the favourable properties, namely light weight and inexpensive production.
The invention relates to a light ceramic material usable, for example, for building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace buildiny materials and/or refactory building materials and to a method for producing the said material.
Light structural materials, based upon lime and cement, are already known as so-called "porous concrete or "foam concreten. To this end, mixtures of calcium-oxide, silicon-dioxide and water, with the addition of foaming agents, or in the oamed condition, are hardened in an autoclave.
Although existing porous light structural materials, as known, for example, from European Patent 0 007 585, have satisfactory strength and other properties important for building purposes, they may be too costly to produce for many applications.
It is the purpose of the invention to provide a new light ceramic material which can be used as a light-weight aggregate and also for producing moulded objects, such as bricks, for heat and/or sound-insulating purposes in particular, and also for refractory building purposes, in the form of light compression-proof mouldings, made from simple initial substances, by an economical method.
According to the invention, is provl~ed a process for producing a lightweight ceramic material for use in building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace building materials and/or refractory building materials, having a bull density of 300 to 700 g/liter, which comprises forming a starting mixture containing 45 to 80 parts by weight of clay, 0 to 50 parts by weight of an aggregate, 15 to 30 parts by weight of water, 0 9 01 to 0,03 parts by weight of a deflocculant and 0,001 to 0,01 parts by weight of a surfactant; foaming the starting mixture at a pressure of 1 to 10 bar by compressed air at a temperature between ambient temperature and 95C to form a foam; molding and drying the foam to give a dried clay blank; and firing the dried clay blank at a product temperature between 600 and 1400C.
In this connection it is particularly desirable to use, as aggregate, calcite, quartz sand, dolomite, feldspar, chamotte, sawdust and coal.
If, for production reasons, a product is required with particularly high green strength, as may be the case with products larger than bricks, a hydraulic binder, such as cement, may be added. One special advantage of the method according to the invention is that the clay used may be simple brick-clay, but Westerwalder stoneware clay, fine stoneware clay, kaolin, montmorlllonite, bentonite or marl may also be used.
It is of special interest, from an economical point of view, that, according to the invention, any mouldings that are unsatisfactory after drying or, where granules are used, any fine granular material separated by screening, can be returned, without further treatment, directly to the initial mixture, since they have merely been dried, not fired, and are therefore still fully reactive.
The method according to the invention usually proceeds in such a manner that the cla~v is stirred up with water and the deflocculating agent to form a thixotrophic suspension containing little moisture. To produce a foam-suspension from the clay suspension, surfactant is added and foaming is carried out in a dispersing unit with the addition of compressed air.
.5~
It is possible to make use of conventional dispersing units, as sold by Messrs. Hansa-Mixer, Bremen, under the trade mark ~ansa-~ixer~ which add specific amounts of compressed air under pressure (1 to 10 bars). The dispersing unit has an additional precision-metering pump by means of which fluid may be added before and, if necessary, during the foaming operation. During the execution of the method according to the invention, it is desirable to use a suhstance opposing the action of the deflocculating agent, a deflocculant-counteracting agent, for example dilute hydrochloric acid, this makes it possible to produce highly viscous, thixotropic, inherently stable foam-suspensions.
The inherently stable, thixotropic foam-suspension is then dried, the water-vapour emerglng readily through the pores because of the high porosity of the material. In this connection it is particularly beneficlal if the mixture of initial materials contains a relatively small amount of water.
The dried material is usually obtained in lengths of about 1 cm.
in diameter, the drying times being not more than 5 minutes at temperatures of 200C This dried material is crushed into granules prior to firing.
Due to the porosity of the material, and above all in the case of objects of small dimensions, very favourable processing is possible, such as drying. With a furnace-temperature of between 1000C and 1400C, corresponding to amaterial-temperature of between 800 and 1000C, it is possible to produce light ceramic materials for building purposes with a firing time of less than 5 minutes, including heating-up and cooling-down times. Treatment at an elevated temperature is particularly desirable if the product is to be used for building purposes, since this mazes it possible to obtain particularly satisfactory strength propertles.
The invention also relates to the use of the light ceramic material in the form of a solid and/or granules as a heat and/or sound-insulating material for building purposes, also as an aggregate for high-temperature building materials such as structural materials for furnaces, refractory building materials, and the like.
The aggregates normally used for refractory building materials for example are, of course, also used accordingly, i.e. additions of clay, maynesite, quartz and the like, as required by the particular application.
The light ceramic material may be characterized in that the mixture preferably contains between 60 and 75 parts by weight of clay, 15 to 20 parts by weight of water, 10 to 20 parts by weight of aggregate; 0.001 to 0.01 parts by weight of surfactant, and 0.01 to 0.03 parts by weight of deflocculating agent.
The invention may be further characterized in that the clay blank is dried at a temperature between ambient temperature and 200C.
Further characteristics and advantages of the `nvention may be gathered from the following description, in which examples embodying the invention are explained in detail in conjunction with the diagrammatical drawing attached hereto, which shows a flow-chart of a method according to the invention.
Thus, 45 to 80 parts by weight of clay, 15 to 30 parts by weight of water, if necessary 0 to 50 parts by weight of an aggregate, and 0.01 to 0.03 parts by weight of a deflocculating agent, possibly with an appropriate amount of a hydraulic bonding agent, are mixed together in a conventional mixer. The following may be used as clay, for example: brick clay, Westerwalder stoneware clay, fine stoneware clay, kaolin, montmorillonite, bentonite or marl. Calcite, quartz sand, dolomite, feldspar, chamotte and/or organic materials such as sawdust or coal may be used as the aggregate. Examples of deflocculating agents are: water-glass, ca:Lcium polyphosphate, sodium polyphosphate, phosphoric acid, chlorides or sulphates, Preferably cement may be added as the hydraulic bonding agent in order to achieve higher green strength The mixture made out of the foregoing constituents, and containing little water, is foamed so as to have a litre-weight of between 30 and 80 g/l, and is dried in moulds or by means of a moulding device. Drying may, if necessaryJ be accelerated by establishing a vacuum or by the use of a drying oven. Drying is extremely simple and rapid because of the high porosity of the material to be dried. The dried products are then placed in a furnace having a temperature of between 1000 and 1400C, corresponding to a product temperature of between about ~00 and 1000C, and are fired. In producing light additives, as used in building concrete and the like, it is desirable to use granular material; this may be obtained by passing the dried products through a crusher and a screening unit which retains the preferred grain-size range and discards the fines; the latter may then be returned to the mixer, as shown in the drawing.
500 kg of marl, 400 kg of crushed, dried foamed clay (produced by crushing rejected, dried and not yet flred foamed clay mouldings), 200 litres of water, 120 g of sodium polyphosphate (deflocculating agent), and 100 g of sodium dodecyl-sulphonate (dispersing agent), were foamed in a dispersing unit made by Messrs. Hansa-Mixer, of Bremen, at a pressure of 3 bars, with compressed air. The foamed product was cast in moulds, passed to a drying oven, and dried at 200C for 10 minutes. The dried, foamed-clay mouldings were removed from the moulds, and were fired for 7 minutes in a corlventional furnace and in the usual way, at a furnace-temperature ox about 1400C corresponding to a product temperature of about 1000C.
This produced yellowish-brown light ceramic panels having the following characteristics:
pH value: 7 - 8 pore diameter: 1 mm.
bulk-density: about 0.6 g/cm3 Products made in this way have good heat- and sound-insulating properties and low hygroscopicity. Panels or bricks made in this way may replace glass-fibre wool, asbestos-fibre, rock-wool or styropor for thermal insulation; they may also be used for facing panels or for light partitions, if low weight per unit of volume is necessary, because the sub-soil has insufficient load-carrying capacity.
Example II
800 kg of kaolin, 200 kg of pumice-stone crushed to a grain-size of between l and 2.5 mm, 200 litres of water and 100 g of 5% phosphoric acid were mixed and added to 300 g of sodium-lauryl-sulphonate foam (lltre-weight 70 g/l). This was followed by forming into lengths in a forming unit, then by crushing, in a conventional roller-crusher, to a grain size of between and 5 mm diameter, followed by screening. The fines were separated, all material below the said grain-size being discarded. The crushed product was passed to a furnace having a furnace temperature OL 1000C, was fired for 5 minutes, and the resulting granular material was cooled and packaged. The resulting material is particularly suitable for light additives, for example for light concrete, gypsum-panels, and the like, and possessed compressive strength, bulk-density, and heat-conductivity coefficients which made it appear particularly suitable for these applications. The pH value was between 7 and 8 and the bulk-density was in the vicinity ox 0.6 ~/cm3.
The addition ox hydraulic bonding agents, such as cement, increased the strength values without impairing the favourable properties, namely light weight and inexpensive production.
Claims (10)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing a lightweight ceramic material for use in building purposes, particularly as a thermal and/or noise insulating material or as an aggregate for high temperature building materials, furnace building materials and/or refractory building materials, having a bulk density of 300 to 700 g/liter, which comprises forming a starting mixture containing 45 to 80 parts by weight of clay, 0 to 50 parts by weight of an aggregate, 15 to 30 parts by weight of water, 0,01 to 0,03 parts by weight of a deflocculant and 0,001 to 0,01 parts by weight of a surfactant; foaming the starting mixture at a pressure of 1 to 10 bar by compressed air at a temperature between ambient temperature and 95°C to form a foam; molding and drying the foam to give a dried clay blank; and firing the dried clay blank at a product temperature between 600 and 1400°C.
2. A process according to claim 1, wherein a deflocculant-counteracting agent is added to produce a highly viscous, thixotropic, inherently stable foam.
3. The process according to claim 1, wherein the dried clay blank is fired at a product temperature between 800 and 1200°C.
4. The process according to claim 1, wherein the clay blank is dried at a temperature between ambient temperature and 200°C.
5. The process according to claim 1, wherein the dried clay blank is fired in less than 5 minutes at a kiln temperature of between 1000 and 1400°C., corresponding to a product temperature between 800 and 1000°C.
6. The process according to claim 1, further comprising adding a hydraulic binder to the clay mixture prior to the molding and drying step.
7. The process according to claim 6, wherein the hydraulic binder is cement.
8. The process according to claim 1, wherein the mixture has between 60 to 75 parts by weight of clay; 15 to 20 parts by weight of water; and 10 to 20 parts by weight of an aggregate.
9. The process according to claim 1, wherein the clay is selected from the group consisting of brick clay, Westerwalder stoneware clay, fine stoneware clay, kaolin, montmorillonite, bentonite and marl.
10. The process according to claim 1, wherein the aggregate is selected from the group consisting of calcite, quartz sand, dolomite, feldspar, chamotte, sawdust and coal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3414967.8-45 | 1984-04-19 | ||
| DE1496784 | 1984-04-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1241350A true CA1241350A (en) | 1988-08-30 |
Family
ID=5673469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000477488A Expired CA1241350A (en) | 1984-04-19 | 1985-03-26 | Light ceramic materials for building purposes and methods for their production |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1241350A (en) |
-
1985
- 1985-03-26 CA CA000477488A patent/CA1241350A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |