FR2499972A1 - PROFILES HAVING HIGH MECHANICAL STABILITY AT HIGH TEMPERATURES, PROCESS FOR THEIR MANUFACTURE AND USE THEREOF - Google Patents

Abstract

PROFILES HAVING GREAT MECHANICAL STABILITY AT HIGH TEMPERATURES, THEIR MANUFACTURING PROCESS AND THEIR USE. THE PROFILES CONCERNED BY THE PRESENT INVENTION ARE MANUFACTURED BY CAREFULLY MIXING CERAMIC FIBERS, OR A MIXTURE WHICH CONSISTS OF 80 BY WEIGHT OF A BAKED FIBROUS GRANULATION AND AT LEAST 20 BY WEIGHT OF FIBERS, WITH CLAY, OF OTHER REFRACTORY PRODUCTS, A PHOSPHATE BINDER, AN ORGANIC BINDER AND WATER, BY COMPACTING THE MIXTURE OBTAINED TO A VOLUME FACTOR OF AT LEAST 3, IF ONLY CERAMIC FIBERS ARE USED, OR AT A VOLUME FACTOR OF ' AT LEAST 1.5, IF USING THE MIXTURE OF FIBROUS GRANULATION AND CERAMIC FIBERS, WHILE MOLDING THIS MIXTURE THEN DRYING THE PROFILE SO MANUFACTURED AND OR CURING AND / OR BAKING IT. USE OF THESE PROFILES AS REFRACTORY SUPPLY PRODUCTS, FOR EXAMPLE.

Description

"Profiles having high mechanical stability at temperatures

  their manufacturing process and their use. "

  The present invention relates to profiles having high mechanical stability at elevated temperatures, a method of

  for their manufacture and use.

  Fibrous ceramic bodies, heat-insulating, consisting of refractory fibers, organic binder or

  which has a reduced strength and a compres-

  high reliability and high values for strength, density and resistance to deformation. Thus, the German patent application filed and accepted in FRG No. 12 74 490 describes a furnace combustion chamber which is formed by forming the fibrous massmixed with binder and in which the binder concentration must decrease through the cross-section. Wall. Suitable binders are clays, alkali silicates,

  aluminum phosphate, colloidal silica with a proportion

  by weight of 5 to 35%, preferably 10%. However, the fibrous body is not suitable to a sufficient extent for high loads because of its thick and hard wall surface.

  and the soft and flexible opposite wall surface.

  In the process according to the German patent application filed and accepted in FRG No. 27 32 387, the mineral fiber plate bonded with an organic synthetic binder must be consolidated by impregnation with an aqueous suspension of a binder clay and then by annealing. In addition, are known from

  European Patent Application 0006362 plates which

  hold in a matrix constituted by a plastic clay,

  mineral fibers of the glass fiber type as fibers

  forçantes. In this case, the amounts of clay are in a range of 29 to 80% by weight and the amount of glass type mineral fibers is in the range of 15 to

X by weight of the plate.

  The object of the present invention is constituted by

  profiles with improved mechanical and thermal properties

  which can be used in particular also as

  replacement products for light refractory plates.

  To achieve this object, profiles having high mechanical stability at high temperatures and good insulating properties and which are prepared from the following composition are used: 100 parts by weight of ceramic fibers or of a mixture consisting of by at least 20% by weight of

  fibers and up to 80% by weight of a

fibrous mixture cui-te,

  2 to 20 parts in clay and / or A 1203 very finely divided

  and / or very finely divided SiO2 and / or very finely divided aluminum hydroxides and / or magnesia and / or very finely divided titanium dioxide

  and / or chromium oxide very finely di-

referred.

  0 to 8 parts by weight of a phosphate binder, calculated as P205, 0 to 10 parts by weight of an organic binder, and 0 to 10 parts by weight of other refractory additives, but o at least 2 parts by weight of binder are present, having a density of 0.5 to 1.8, a hot flexural strength at COOC of at least 0.8 N / rami,

  a thermal shock resistance ('WB) of at least 25 cooled

suddenly in the air.

  Advantageous forms of embodiment of the profiles

  forms of the invention consist in using bentonite com-

  clay; pulverized porcelain, chamotte or corundum in the form of hollow pellets as another additive

  refractory "sodium polyphosphate or α-monophosphate

  luminium as phosphate binding and methylcellulose as

organic binder.

  The manufacture of profiles in accordance with this

  vention is carried out according to the method which consists in the first

  first stage (a) mixing the aforementioned ingredients in the indicated ranges of amounts with water in a mixer and then compacting, by molding, the mixture obtained in step (a) at a volume factor of at least 3 if you use only ceramic fibers or at a factor

  at least 1.5 if a mixture of 80 parts is used.

  by weight of fibrous granules and 20 parts by weight

  weight of ceramic fibers, and (c) drying the profile

  in stage (b) and / or harden and / or cook. Preferred embodiments of this process are characterized by

  because in stage (b) the compaction is effected

  at a factor of 5 to 8 if only

  ceramics or at a factor of 2.5 to 4 if a mixture of 80 parts by weight of fibrous granules and 20 parts by weight of ceramic fibers is used, and this while making fibrous slabs, and by the fact that we use

  fibers prepared as ceramic fibers.

  The profiles according to the invention can be used

  in many areas, particularly as

  placement for known light refractory slabs. In this case, these profiles have the advantage that they present a

  density lower than these slabs and that they have a distribution

  very narrow bution of pore size and size

  low pores. Their thermal conductivity, despite the compaction

  tage is of the same order of magnitude as that of fiberglass profiles1knownnon-compacted during their manufacture,

  which have been manufactured by simple vacuum forming. Opposite-

  In this connection, the profiles according to the invention

  however, a particularly high resistance.

  Due to their high mechanical strength, the profiles according to the invention are particularly suitable as filling materials for expansion joints between the bricks of rotary tubular furnaces. So far, asbestos has been used but the use of asbestos has been

  little because of its dangerous health effects.

  As mineral fibers, all ceramic fibers

  such as mineral wool or silico-based fibers

  aluminum cate containing about 40 to 95% by weight of A1203e

  can be used for the profiles of the present invention.

tion.

  Other refractory additives used in

  yarns according to the present invention have the general additives

  commonly used for fibrous profiles such as porcelain

  pulverized wool, chamotte, corundum in the shape of a ball-shaped

  hollow or vermiculite The binders present in the profiles of the present

  are phosphate binders, for example borophosphorus

  phate, aluminum phosphate or sodium polyphosphate having a degree of polymerization of n> 4 and in particular

from n = 6 to 10.

  The organic binders present in the profiles conforming

  my invention is the binders generally used in refractory or fire-resistant profiles, wedges the starch,

  the sulphite waste liquor, SiIasse, in part

  methylcellulose. The amount of binder indicated is

  calculated by solid organic binder, that is, without the quantity

water.

  Both the phosphate binder and the organic binder can be used both in the dissolved state and in solid form: during the use of methylcellulose. which is generally added in the form of an aqueous solution at 5 X in

  part of this methylcellulose is, however,

  tagely incorporated, especially if large quantities

  are used as an organic binder in a fine solid form

  Otherwise, the amount of water introduced into the composition by such a binder solution would become too great. The clay and / or Al 2 O 3 very finely divided and / or SiO 2 very finely divided and / or the aluminum hydroxides and / or the very finely divided magnesia and / or the titanium dioxide

  very finely divided and / or very finely divided chromium oxide

  Se, present in the composition of the profiles of the present invention, are the constituents used, as is known, in the field of refractories. In the case where the clay is used, it is then a conventional binder clay or even a special clay preferably used, such as for example bentonite. By the term "very finely divided" used herein, in connection with the aforementioned constituents, it is to be understood that these constituents are present in the state finely.

  ground or even in the colloidal state. In particular when using

  of these colloidal materials, such as

  Colloidal SiO2 or colloidal aluminum oxide, it is pos-

  sible to use only small amounts of binder,

  almost to the lower limit of 2 parts by weight of such binder. The binder can consist of only a phosphate binder or only an organic binder, but advantageously a mixture of both the phosphate binder and the organic binder is used, the use of the phosphate binder and methylcellulose as organic binder, quantities

  substantially equal weights, is particularly preferred.

  Advantageously, the composition of the profiles according to the invention contains from 5 to 15 parts by weight of clay or the other constituents mentioned per 100 parts by weight of ceramic fibers. Particularly advantageous is the use of a mixture of clay and in particular of bentonite and from 1 to 3 parts by weight of one of the other constituents mentioned above,

  in particular of colloidal silica.

  During the manufacture of the profiles of the present invention

  tion, a mixture consisting of the ceramic fibers is prepared.

  or the mixture of ceramic fibers and granulation

  fibrous material, clay or other constituents

  the phosphate binder, possibly present, the other

  refractory materials, if any, and the organic binder

  only possibly used, adding water. When the phosphate binder and / or the organic binder already exist in the form of a solution, generally an aqueous solution, the addition of water

  may not be necessary. During manufacture in the sta-

  Of (a) the process of the present invention, generally 5 parts by weight of water per 100 parts by weight of ceramic fibers are in the mixture. The phosphate binder, such as sodium polyphosphate and aluminum monophosphate, as well as the organic binder such as sulphite waste liquor or methylcellulose, can be incorporated in the solid state, but it is also possible to add a part of this binder.

  in the form of a solution and the remainder in solid form.

  The fired fibrous granulation used during manufacture

  cation of the profiles according to the present invention is de-

  is described in detail in the French patent application corresponding to the patent application filed with the applicant P 3105579.6 same day. The preparation of this fibrous granulation is carried out as follows: a) 100 parts by weight of ceramic fibers, 2 to 15 parts by weight of clay and / or of very finely divided Al 2 O 3 and / or of SiO very finely divided and and / or very finely divided aluminum hydroxides and / or magnesia and / or very finely divided titanium dioxide and / or very finely divided chromium oxide, optionally up to parts by weight of other refractory additives and 1 to 8 parts by weight of phosphate binder optionally adding plasticizers are carefully mixed

  with about 2 to 25 parts by weight of water in a mixture of

geur,

  (b) the mixture obtained in stage (a) is

volume of at least 3, and

  (c) the product obtained in stage (b) is

  cooked and cooked at temperatures from 800 to 1550 Cpuis crushed

until the desired granulation.

  Materials: Ceramic fibers, clay or other

  mentioned. refractory additives and the binder

  phosphates, used for the preparation of this granulation

  breusecorrespond to the subjects as they have been

  previously written. As a plasticizer, is preferably used

  methylcellulose. For the preparation of fibrous granulation, compaction in stage (b) can be carried out in an extruder, a rotary press or a lighterBr. The mixture of the constituents in stage (a) for the preparation of this fibrous granulation can be carried out in any suitable mixer, for example in a mixer Drais'. Advantageously, for the preparation of a fibrous granulation of this kind, prepared fibers are used as

  ceramic fibers, such as those which can be used equally

  for the production of the profiles of the present invention.

  Grinding in stage (c) for the preparation of this grading

  fibrous tissue can be performed in any appropriate device

  the maximum grain size is usually 6 mm.

  This grinding can, however, also be adjusted in a specific range, for example a product having a granulatior of between 2 and 3 m can be obtained simply by grinding in the conventional grinding devices and possibly by sieving.

  desired granulations. The granular material thus obtained

  nude has a density of 0.7 to 1.75 g / cm3 and has a pore volume of the order of magnitude of 35 to 75%. The amount of the plasticizer optionally added in step (a) for the preparation of this fibrous granulation depends on the compacting device used in stabe (b). For example, when using methylcellulose and compaction in an extruder, a quantity of 4 parts by weight of methylcellulose is added, half of this amount of methylcellulose

  being in the form of a 5% solution in water and the other me-

  is added as dry methylcellulose. But if the compaction is done in an extruder, the quantity

  water used in stadium (a) can be up to 100

by weight.

  The quantity of water used for the production of

  of the present invention should be kept as low as possible, preferably only up to 15 parts by weight of water per 100 parts by weight of ceramic fibers, and in particular, preferably only 10 parts by weight of water. per 100 parts by weight of ceramic fibers are

  added, so that a pasty mass is obtained.

  The advantage in the use of a fiber mixture

  However, in the manufacture of the profiles according to the invention, only a small amount of water is needed. In this case, the quantity

  of water depends on the proportion of ceramic fibers and granu-

  the fibrous solution cooked in the mixture, the amount of water

  the lower the proportion of granu-

  The fibrous solution cooked in the mixture is larger. The utili-

  of a mixture of 50% by weight of ceramic fibers and 50% by weight of fried fibrous granulation was found to be

particularly advantageous.

  The pasty mass obtained in stage (a) for the manufacture

  in the process step according to the

  present invention loaded into a suitable press, for example

  in a multi-platen press or a bench press or even an isostatic press and is pressed for a time

249; 972

  appropriate depending on the type of press used. In

  multi-platen press, the press duration is ge-

typically 5 to 20 seconds.

  It is essential that in the production of the profile according to the present invention in stage (b) / the compaction is carried out at a volumetric factor of at least 3 if

  Only ceramic fibers are used on a volumetric

  at least 1.5 if a mixture of 30 parts by weight of fired fibrous granulation and 20 parts by weight of ceramic fibers is used. By using a mixture of ceramic fibers and fibrous granulation in other proportions,

  this minimum compaction factor is between 3 and 1.5.

  The preferred value of the compaction factor in the case where only the cm.ram fibers are used is between 5 and 8 and in the case where a mixture of 80 parts by weight of fibrous granulate and 20 parts is used. in weight of ceramic fibers is between 2, 5 and 4. Of course for other proportions of ceramic fibers and granulation

  fibrous firing, in a mixture the compaction factors

  are between the limit values mentioned below.

  above. The maximum compaction volume factor, using only ceramic fibers was about 12 to 14 while

  that using a mixture of 80 parts by weight of granular

  fibrous solution and 20 parts by weight of ceramic fibers,

its value is from 6 to 8.

  In the case where the profiles according to the invention are manufactured in the form of fiber slabs, these may

  have a thickness of 1 to 50 mm.

  After pressing, the profiles in stage (c) of the process of the present invention are dried at elevated temperatures, preferably between 110 and 180 C, and then they can be

  cured at temperatures between 250 C and 6001C or

  I cooked at temperatures between 800 C and 16500C. The maximum cooking temperature as well as the temperature

  However, the limit of use depends mainly on

  ramiques used in the starting mixture, and in a low

  measurement of the other refractory additives possibly present.

  The ceramic fibers are in their state of readiness

  in the form of bulk wool, but they are in particular

  strongly compacted. To allow even better bonding of the fibers per the bind used and a better wetting of the surface by the less concentrated liquids, the fibers

  are advantageously prepared before molding.

  For this purpose, mixing devices comprising heads

  stirrers rotating at high speed, so-called turbo mixers

  can be used, whereby the large agglomerates existing in the fibers in the delivery state are broken down,

  without the fibers being badly crushed

missible.

  In the process of the present invention, it is possible

  In the case where no fried fibrous granulation is used, perform step (a) also in a turbine mixer of this type, that is to say in a mixer comprising rotating nozzle heads. at high speed, which means that the disintegration of the fibers and their mixtures have been carried out

  with the other constituents added in this stage (a), in particular

  with the clay and / or the other constituents mentioned,

  phosphated binder, the other refractory additives

  optionally the organic binder. But in this case, only dry solids are added to achieve on the one hand. the disaggregation of the agglomerated fibers, and secondly, the homogeneous mixing of the added materials. Then, the water and optionally the binder used in the form of a solution, are

  then sprayed into the mixing vessel and mixed.

  But of course, it is also possible to perform the disintegration of the ceramic fibers first in a turbine mixer and then to add to another mixer, by

  example a Drais mixer or a mixerEirich the other additives.

  This procedure is particularly used when using verhiculite or corundum in the form of hollow pellets as another refractory additive, otherwise a crushing of these

  dying occurs, also when using granular

  fibrous ion cooked in the mixture with ceramic fibers.

  The profiles according to the present invention have the particular advantage that, because of their relatively high content of ceramic fibers, they have very good thermal insulation properties and because of the compaction and

  volume factor of at least 3 or 1.5 when manufacturing them

  cation.They exhibit relatively good mechanical stability.

  In addition, their thermal shock resistance (TWIB) is remark-

  quable and amounts to more than 25 cycles.

  The present invention is explained in detail using

following examples.

  In the examples, ceramic fibers of the Al 2 O 3 -SiO 2 system are used and for this purpose fibrous material A having 47% Al 2 O 3 and 53% SiO 2, with working temperature up to 1260 ° C and a fibrous material B suitable for higher processing temperatures having 95%

A1203 and 5% SiO2.

  The mixtures are prepared in part in a turbine mixer which is equipped with a high-speed rotating head (3000 rpm). In this mixer, the material

  fibrous tissue is at first well disintegrated and, moreover, a rich gene-

  very charged with the constituents of the iguable and fluid mixture,

  is formed simultaneously. The mixture consisting of granular

  fibrous lat is transformed into fibrous article during subsequent press treatment having apparent density

  more or less high and a particularly homogeneous structure.

  With a mixer that is equipped with mixing arms function-

  at a relatively low speed, for example a mixture of

  On the other hand, on the other hand, less intense fiber disintegration is achieved and the work of the mixture is not as homogeneous. The 50% aluminum monophosphate solution is introduced into the mixer as a fog in the region of the high speed head. Thus, with the smallest volume of liquid, for example 10% by weight of MP-6.6 liters, a complete wetting of the surface of the agglomerates is

  got. The water is then injected in the same way. Water dis-

  the dry methylcellulose possibly present and entral-

  thus not a good dry resistance of the blanks.

  of molded bodies Preparation of fired fibrous granulations: a) 100 parts by weight of ceramic fibers A, parts by weight of binder clay, containing 35% by weight of Al 2 O 3 and 1.5 parts by weight of methyl cellulose are mixed.

  powder in an Eirich mixer for 10 minutes.

  utes. Next, 10 parts by weight of a 50% by weight solution of aluminum monophosphate and 2 parts by weight of water are pulverized onto the mass in the mixer, while continuing mixing and mixing for a further time.

minutes.

  The product removed from the mixer is pressed in one

  30 mm thick, in a multi-plate press at a pressing pressure of 30 N / mm 2, resulting in compacting at one

factor of 5.5.

  The slab product obtained is then dried at 110 ° C. for 24 hours in an oven and then baked at different temperatures each time for 24 hours.

  then ground to a maximum grain size of 3 mm.

  Granulation has the following properties:

Table I

  Cooking Temperature (C) 800 1350 1510 Bulk Density R (g / cm3) 1.34 1.52 1.77 Specific Gravity S (g / cm3) 2.60 2.70 2.75 Volume of Pore Pg ( % by volume) 47.7 43.7 35.6 b) The procedure of Preparation (a) is repeated, but

  a mixer & turbine is used to break up the fibers.

  The pressing pressure in stage (b) is 10 or N / mm 2, compaction is carried out at a factor of 4 and 5,

respectively.

  After cooking at 1350 C for 24 hours and crushing

  gejon obtains granulation with the following properties

your:

Table II

  Pressing pressure (N / mm) 10 15 R (g / cm) 0.7 1.02 Specific weight (g / cm3) 2.7 2.7 g (% by volume) 74 63 c) The procedure of the Preparation (a) is repeated, but the amount of aluminum monophosphate is then 15 parts by weight and the amount of water is 5 parts by weight, with a mixing time reduced to 20 minutes. After cooking at 1350 ° C. for 24 hours and grinding at the desired granulation, it has the following properties:

Table IiI

  R (g / cm3) 1.29 S (g / cm3) 2.69 μg (% by volume) 53.8 d) The procedure of Preparation (a) is repeated, but 8 parts by weight of flour are added. chamotte in the first stage. In addition, it adds only 8.3

  parts by weight of the 50% by weight solution of mono-

  aluminum phosphate but 4 parts water in the stadium

mixing.

  The pressing pressure in the compaction stage is 30 N / mm2, which gives a compaction to a factor of

volume of 5.2.

  The slab-shaped product is dried at 180 ° C. and the samples are fired at different temperatures indicated in Table IV below. Then, the dried or cooked product is milled to a maximum grain size of 3 mm. The granulation obtained has the following properties:

Table IV

  Processing temperature (C) 180 800 1200 1300 1500 Bulk density, R (g / cm) 1.30 1.26 1.31 1.34 1.48 Specific weight (g / cm3) 2, 60 2.60 2.65 2.68 2.72 Pg (% by volume) 50.0 51.5 50.5 50.0 45.6 The invention is now explained in detail using

  illustrative but nonlimiting examples hereinafter.

EXAMPLE 1

  The following composition is used: Parts by weight Ceramic fibers A (47% by weight of Al 2 O 3) 100 Binder clay (at 35% by weight of Al 2 O 3 Dry methyl cellulose 1.5 Solution of aluminum monophosphate, (50% by weight The ceramic fibers A are loaded with the binder clay and the dry methylcellulose in the Eirich mixer and then treated in this mixer for 20 minutes, so that a homogeneous mixture is obtained. to mix, the solution of aluminum monophosphate then

  water is sprayed and then we continue to mix carefully

  is lying. Then, with a pressing pressure of 30 N / mm2,

* compressed in bricks with dimensions 405 x 135 x 50 mm.

  The compaction factor is 6.0.

  Then, the bricks are dried for 4 hours at C and then baked at different temperatures for different times. The properties measured on the bricks after cooking at different temperatures are as follows:

Table V 800oC / 8h 13500C / 6h 1510oC / 6h R (g / cc) 1.34 1.52 1.77 Pg (% by volume)

  47.7 43.7 35.6 VM '(N / mm2) 1408 1303 5291 KBF (N / mm2) 5.0 4.4 8.2

TWB "> 25> 25 - 25

  HBF ', 1000 C (N / mm2) 4.7 6.6, 11.6 HBF ,. 1200 C (N / mm2) 6.2 5.9 9.6 Withdrawal after 24 h at 1400oC -3.19 -1.89

1500 C -6.94 -3.35 -0.16

  1600oC -10,32 -7,70 -5,45 1350oC / 6h 1510oc / 6h Chemical analysis Al203 (%) 44.7 A203 SiO2 (S) 50.7

P205 (%) 2.95

  Thermal conductivity, WLF (W / m K at 700 C) 0.45 VM = modulus of deformation ^ KBF = resistance to cold bending LTWB = thermal shock resistance "XHBF = resistance to hot bending

EXAMPLE 2

  The same mixture is made by operating in the stirring mixer at a lower pressing pressure and after baking at 1350 ° C., bricks having the following properties are obtained; the properties for a pressing pressure of N / mm 2 indicated are drawn. of Table V for comparison:

Table VI

  Pressing pressure (N / mm2) Compaction factor Baking temperature (C) Cooking time (h) R (g / cm3) Pg (% by volume) KBF (N / mm2) HBF, 1000 C (N / mm2) HBF, 1200 C (N / mm) HBF, 1400 C (N / mm2) WLF, (W / m K at 700 C)

EXAMPLE 3

  The composition xample 1 6.0 1.52 43.7 4.4 6.6, 9 0.45, 4 1.34 58.0 4.1, 6 0.25 Exemp 2

10

4,4 3,5

1350 1350

24 24

1.02 0.7

63.0 74.0

0.9 0.7

2.0 0.8

2.3 0.9

0,20 0,16

  Next: Portions of ceramic fibers A (47% by weight of Al2O3) Binder clay (35% by weight of Al2O3) 8000c / 8h Methylcellulose, dry Aluminum monophosphate (50% by weight solution) Water Parts by weight 1.5 In step (a) of the process of the present invention, an Eirich mixer is used. The dry constituents are first loaded in the mixer "Eirich" then mixed for minutes, then the solution of aluminum monophosphate and water are sprayed. After mixing for a while

  minutes, the mass is removed from the mixer.

  As in Example 1 above, the mixture is trans-

  formed by compression in bricks, in a press at a pressure

  pressing pressure of 30 U / mm2. The compaction factor is 5.2.

  The compacted bricks are dried at 1100C for 4 hours puffed for 6 hours at 1350 C. The properties determined on the bricks obtained are as follows:

Table VII

  R (g / cm3) 1.29 Pg (% by volume) 53.8 HBF at 1000 C (N / mm2) 2.1 KBF (N / mm2) 2.6 WLF (W / m K at 700 C) 0 A comparison of the bricks made according to Examples 1, 2 or 3 shows that, during treatment in a turbine mixer and at equal pressing pressure, profiles having a higher cold flex resistance can be used.

  obtained. With the treatment in a mixer "Eirich, that is

  that is to say without disintegrating the ceramic fibers, it is

  to slightly increase the amount of phosphate binder and also the amount of water, the amount of water to be

  advantageously between 8 and 10%.

  EXAMPLES 4 and 5 The following compositions were used: Ceramic fibers B (95% by weight of Al 2 O 3) Binder clay (at 35% by weight of Al 2 O 3) Dry methylcellulose Aluminum monophosphate solution Parts by weight

100

  1.5 to 50% by weight 12 Water 3 The preparation of the composition is carried out in the

  stage (a) according to the procedure of Example 2, i.e.

  say using a turbine mixer.

  The mixture obtained in stage (a) is compacted into bricks according to the procedure of Example 2 at a pressing pressure of 9 or 20 N / m 2, then the bricks are dried for 4 hours at 110 ° C. and then cooked for 24 hours. at 1350cC. The properties of the bricks thus obtained are as follows:

Table VIII

Example

  R (g / cm) Compaction factor Pg (% by volume KBF (N / mm2) HBF, 900 C (N / mm2 HBF, 1000 C (N / mm) HBF, 1400 C (N / mm2) WLF (W / m K at 700 C)

EXAMPLES 6 to 9

  0.52 3.5 84.2 0.9 0.8 0.7 0.19 The following composition is prepared: Parts 1, 01 6.7 69, 4 1.9 3.4 0.35 by weight Ceramic fibers A (at 47% by weight of Al 2 O 3) Ceramic fibers B (at 95% by weight of Al 2 O 3) Binder clay (at 35% by weight of Al 2 O 3) Very finely ground alumina, L 44 ym Dry methylcellulose Solution of aluminum monophosphate

at 50%

  Water Parts by Weight 1.5 According to the procedure of Example 2, the mixture of Example 6 is processed in a turbine mixer and at the pressing pressure mentioned in Table IX below.

  is compacted into bricks, according to the

  In Examples 7 to 9, an Eirich mixer is used. After drying at 110 ° C. for 4 hours, the bricks

  are cooked for 24 hours at different temperatures

  also in the table. The properties of

  thus obtained are shown in the table.

  Instead of compacting the mixture indicated here in bricks having the dimensions indicated in Example 1, these mixtures are compacted into slabs having the dimensions of 360 x 360 x 18 mm in a multi-plate hydraulic press. These slabs represent remarkable refractory products of charging for example during the cooking of the products of

Fine ceramics or porcelain.

Table IX

  Example 6 Pressing pressure (N / mm2) Compaction factor Drying (C) Cooking temperature (C) Properties: R (g / cm3) Pg (% by volume) KBF (N / mm2) HBF, 1000 C (N / mm2) mm2) HBF, 1400 C (N / mm2) 3.8 0.57 79, 9 0.4 0.8 0, 8, 3 1.22 62.1 3.5 4.5 36 WLF (W / m K) at 700 C) 0.22 0.47

EXAMPLE 10

The following composition is used:

8 9

, 3 1.22 62.2 4.6, 3 1.31 59.3 4.2

4.9 5.6

0.49 0.53

  Fibrous granulation (a) Ceramic fibers B 35% binder clay A1203 Very fine milled alumina, z 44 Mm Very finely ground chromium oxide, C 44 ym Aluminum monophosphate solution (50% by weight) Sodium polyphosphate4Solid Water Parts in Weight 0.5 Fibrous granulation, clay, alumina and chromium oxide are loaded with solid sodium polyphosphate in an Eirich mixer, then 5 parts by weight of water are sprayed and mixed for 5 hours. Then 20 parts by weight of B ceramic fibers are added and then

  mix again for 10 minutes, then the solution of mono-

  Aluminum phosphate is added and mixed again for minutes. The mixture removed from the mixer is comapacted in slabs of 405 x 135 x 15 mm at a pressing pressure of N / mm 2 and then dried for 24 hours at 110 ° C. and the slabs are fired.

  8 hours at 800 C or 1350 C. The product obtained is de-

  completed the following properties:

Paintings

  Cooking Temperature (OC) 800 1350 R (g / cm) 1.8 1.8 Compaction Factor 2.0 2.0 Pg (% by volume) 35.8 35.8 KBF (N / mm2) 2.65 6.4 HBF, 1000 C (N / mm 2) 4.5 7.0 WLF (W / m K at 700 C) 0.70 0.65

EXAMPLE 11

  The following composition is used: Parts by weight Ceramic fibers A 100 Corundum in the form of hollow pellets 3 mm 10 Clay at 35% Al 2 O 3 5 Magnesia 2 Borophosphate solid 4.5 Water 9

  The fibers are first broken up for 10 minutes.

  in a turbine mixer. Then, in an Eirich mixer, the corundum in the form of hollow pellets, the clay and the water are charged, they are mixed for 5 minutes, then

  magnesia and borophosphate are added and mixed

  for another 5 minutes. Then, the disaggregated fibers in the turbine mixer are introduced into the mixer

  "Eirich 'and mixed for another 20 minutes.

  From the mixture obtained, slabs are manufactured according to the procedure of Example 10. These slabs are

  cooked at 800 ° C or 1350 ° C. after drying at 120 ° C.

  The following properties are determined:

Table XI

  Cooking temperature (C) 800 1350 R (g / cm3) 1.15 1.18 Compaction factor 4.1 4.1 Pg (% by volume) 51.9 54.6 HBF, 1000 C (N / mm2) 2.8 4.1 WLF (W / m K at 700 C) 0.63 0.65

EXAMPLE 12

  The following composition is used: Parts by weight Ceramic fibers A 100 Binder clay 10 Dry sulfitic wastewater 9 Water 9 In a mixer Eirich 'ceramic fibers, clay

  and the solid sulphitic waste liquor are mixed during

  10 minutes then the water is sprayed on the mixture and mixed for another 10 minutes. At a pressing pressure of 30 N / mm 2, bricks are compacted as in Example 1. After drying at 110 C for 24 hours, these bricks are fired at 800 C or 1350 C. On bricks, the properties The following are determined: Table XII Cooking temperature (C) 800 1350 R (g / cm3) 1.18 1.28 Compaction factor 5.1 5.1 Pg (% by volume) 54.6 52.6 HBF, 1000 C (N / mm2) 1.5 2.9 WLF (W / m K at 700 C) 0.27 0.28

Claims (10)

  1.- Profile having a high mechanical stability to   high temperatures, prepared from the following composition   100 parts by weight, either of ceramic fibers, or of a mixture consisting of at least 20% by weight of fibers and up to 80% by weight of fired fibrous granulation, 2 to 20 parts by weight of clay and / or very finely divided Al 203 and / or very finely divided SiO 2 and / or very finely divided aluminum hydroxides and / or magnesia and / or very fine titanium dioxide   divided and / or very fine chromium oxide   0 to 8 parts by weight of a phosphate binder, calculated as P205, 0 to 10 parts by weight of an organic binder, and 0 to 10 parts by weight of other refractory additives, but o at least 2 parts by weight Binder weights are present, with a density of 0.5 to 1.8, a hot flexural strength at 1000 ° C of at least 0.8 N / mm 2 a thermal shock resistance of at least 25 cools abruptly in the air.   2. Profile according to claim 1, characterized by   the fact that it contains bentonite as clay.   3. Profile according to claim 1, characterized in that it contains pulverized porcelain, chamotte or corundum in the form of hollow pellets. other refractory additive.   4. Profile according to claim 1, characterized by   the fact that it contains sodium polyphosphate or mono-   aluminum phosphate as phosphate binder.   5. Profile according to claim 1, characterized in that it contains methylcellulose as organic binder. 6. A process for the manufacture of a profile according to claim 1, characterized in that: a) 100 parts by weight, either of ceramic fibers or of a mixture consisting of at least 20% by weight of fibers and up to 80% by weight of a fired fibrous granulation is carefully mixed with 2 to 20 parts by weight of very finely divided clay and / or Al 203 and / or very finely divided SiO 2 and / or hydroxides of aluminum and / or very finely divided magnesia and / or very finely divided titanium dioxide and / or very chromium oxide   finely divided, 0 to 8 parts by weight of a phosphate binder   T, calculated in P205, 0 to 10 parts by weight of an organic binder, but o at least 2 parts by weight of a binder   are present, as well as with 0 to 10 parts by weight of   very refractory additives as well as with water in a mixer, b) the mixture obtained in stage (a) is compacted by molding to a volume factor of at least 3, if the ceramic fibers are used alone, or at a volume factor of at least 1.51 if a mixture of 80 parts by weight of fibrous granulation and 20 parts by weight of ceramic fibers is used, and c) that the profile produced in stage (b) is dried and /or hardened and / or cooked.   7. A process according to claim 6, characterized by   compaction in stage (b) is carried out on a   from 5 to 8, if the ceramic fibers are used alone, or by a factor of 2.5 to 4, if a mixture of 80 parts by weight   fibrous granulation and 20 parts by weight of ramic is used.   8. A process according to claim 6 or 7, characterized in that the compaction in stage (b) is carried out while by making slabs of fibers.   9. A process according to claim 6, characterized by   prepared fibers are used as ceramic fibers. nomic.   10.- Use of the profiles according to any of the   1 to 5, as refractory products,   that is, as supports for the objects to be cooked.